Methods, compositions for treatment, biomarkers, and diagnosis for colorectal cancer

Abstract

Provided herein are methods of treatment, biomarkers, and diagnosis of cancer with monoamine oxidase (MAO) inhibitors and MAO combination therapies. The MAO inhibitor for the disclosed cancer treatment method can be coupled to a near-infrared dye by a linker to increase the potency and selective cytotoxicity of the MAO inhibitor against cancer. The disclosed methods of treating cancer also include administering a therapeutically effective amount of a near-infrared conjugated MAO inhibitor and an immune checkpoint inhibitor. Other aspects of the invention disclosed are methods of identifying subjects suitable for cancer treatment with a monoamine oxidase inhibitor.

Description

METHODS, COMPOSITIONS FOR TREATMENT, BIOMARKERS, AND DIAGNOSIS FOR COLORECTAL CANCERCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of priority under 35 U.S.C. §119(e) of U.S. Provisional Application No. 63 / 455,142, filed March 28, 2023, the contents of which are incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTIONFIELD OF THE INVENTION

[0002] The present disclosure relates generally to cancer and more specifically to the use of monoamine oxidase (MAO) inhibitors for colorectal cancer diagnostics and treatment.BACKGROUND INFORMATION

[0003] Colorectal cancer (CRC) ranks as the third most frequently diagnosed cancer in both men and women, posing a significant challenge to cancer mortality worldwide. The American Cancer Society’s 2023 report projects about 150,000 new CRC cases and 52,550 deaths in the United States alone. Despite advancements in treatments, the prognosis for metastatic CRC, especially for patients with inoperable disease, remains bleak, with a five-year survival rate of about 10%. This stark reality underscores the critical and urgent need for more effective CRC treatments.

[0004] Monoamine oxidases A and B (MAO A and B), key mitochondrial enzymes, play crucial roles beyond the central nervous system, impacting various tissues. Their increased expression has been linked to a higher risk of several cancers, including prostate, glioma, and renal cancers, by promoting processes like reactive oxygen species (ROS) production, epithelial to mesenchymal transition (EMT), and stabilization of hypoxia-inducible factor (HIF) 1, all of which contribute to metastasis. As a result, targeting MAO A has emerged as a promising universal strategy in cancer therapy, transcending the traditional focus on specific cancer types.

[0005] Traditionally, MAO inhibitors have been utilized in treating conditions like depression and Parkinson’s disease. However, research involving colorectal adenocarcinomahas uncovered a significant overexpression of MAO B in CRC tissues, associated with higher recurrence rates and worse prognosis. This revelation underscores the potential of MAO inhibitors, not just in the realm of neurological disorders but as a groundbreaking approach in cancer treatment across various types.

[0006] A significant breakthrough has been the development of new cancer therapeutic by conjugating a near-infrared dye with the MAO A inhibitor clorgyline, known as NMI. This compound specifically targets cancer cells, offering both therapeutic and diagnostic capabilities non-invasively. Patents awarded for the chemical composition and synthesis of these near-infrared dye-conjugated MAO inhibitors, along with the use of NMI and MAO A inhibitors, signal a novel treatment avenue against a spectrum of cancers, including prostate and brain cancers. NCI60 screening has confirmed NMI’s anticancer effects across a broad array of cancer types, underscoring its universal potential.

[0007] The present disclosure unveils a novel therapeutic strategy that, while initially focused on CRC, demonstrates broad applicability to all cancers, including those with microsatellite instability (MSI) or microsatellite stability (MSS) issues. This approach, underpinned by comprehensive research conducted both in vitro and in vivo, leverages NMI in conjunction with inhibitors of MAO A and B. It introduces pioneering opportunities not only in cancer immunotherapy but also in bridging significant gaps across the entire oncology spectrum.

[0008] The emergence of immune checkpoint inhibitors (ICI) has marked a milestone in cancer treatment. Yet, their efficacy in CRC and other cancers is curtailed by resistance mechanisms, particularly in patients with MSS tumors. The advent of NMI, synergized with MAO A and B inhibitors, represents a significant leap forward, enhancing the effectiveness of ICIs and offering a new pathway for surmounting current treatment limitations. This strategy holds promise for metastatic CRC, including the dMMR-MSI-H subset resistant to ICIs and the pMMR-MSI-L CRC tumors, which are traditionally unresponsive to current immunotherapies.

[0009] The development of such innovative therapeutic strategies is imperative to address the evolving treatment needs of not just CRC but all cancers. Concentrating on the pressing need for more effective, versatile, and resistance-defying therapies, the present invention stands to profoundly influence cancer management globally. By setting the stage for futurebreakthroughs in oncology, it underscores the universal potential of the present disclosure against the multifaceted challenges presented by various cancer types and their microsatellite statuses.SUMMARY OF THE INVENTION

[0010] The present invention is based on the seminal discovery that monoamine oxidase inhibitors are effective for treating and diagnosing cancer, for example, colorectal cancer.

[0011] In one embodiment, the invention provides a method of treating colorectal cancer in a subject in need thereof comprising administering a therapeutically effective amount of a monoamine oxidase (MAO) inhibitor to the subject, thereby treating the colorectal cancer.

[0012] In some aspects, the MAO inhibitor is selected from a MAO A inhibitor, a MAO B inhibitor, a MAO A / B inhibitor, or a combination thereof. In some aspects, the method comprises administering the MAO A inhibitor to the subject. In some aspects, the MAO A inhibitor is a near-infrared conjugated monoamine oxidase A inhibitor (NMI), clorgyline, bifemelane, moclobemide, pirlindole, toloxatone, minaprine, or a combination thereof. In some aspects, the MAO A inhibitor is NMI or clorgyline. In some aspects, the MAO A inhibitor is NMI. In some aspects, the NMI is:or an alternate salt, solvate, tautomer, or zwitterion thereof.

[0013] In some aspects, the method comprises administering the MAO B inhibitor to the subject. In some aspects, the MAO B inhibitor is deprenyl, selegiline, rasagiline, pargyline, or a combination thereof. In some aspects, the MAO B inhibitor is deprenyl.

[0014] In some aspects, the method comprises administering the MAO A / B inhibitor to the subject. In some aspects, the MAO A / B inhibitor is phenelzine, tranylcypromine, or a combination thereof.

[0015] In some aspects, the method comprises administering the MAO A inhibitor and the MAO B inhibitor to the subject. In some aspects, the MAO A inhibitor is NMI. In some aspects, the MAO B inhibitor is deprenyl.

[0016] In some aspects, the colorectal cancer comprises colorectal carcinoma, colorectal adenocarcinoma, colorectal melanoma, Dukes primary colorectal lymphoma, gastrointestinal stromal cancer, leiomyosarcoma, or colorectal carcinoid tumors. In one aspect, the colorectal cancer comprises colorectal carcinoma, colorectal adenocarcinoma, or metastatic colorectal cancer. In some aspects, the colorectal cancer comprises colorectal carcinoma, colorectal adenocarcinoma, or metastatic colorectal cancer.

[0017] In some aspects, the cancer exhibits MAO A activity, MAO B activity, or a combination thereof.

[0018] In some aspects, the method further comprising administering an immune checkpoint inhibitor. In some aspects, the immune checkpoint inhibitor is selected from a programmed cell death 1 (PD-1) inhibitor, a programmed cell death ligand 1 (PD-L1) inhibitor, or a CTLA-4 inhibitor.

[0019] In some aspects, the therapeutically effective amount of the MAO inhibitor is between about 1 and 250 mg / kg / day, between about 1 and 25 mg / kg / day, between about 5 and 25 mg / kg / day, between about 5 and 50 mg / kg / day, between about 10 and 50 mg / kg / day, between about 10 and 50 mg / kg / day, between about 10 and 100 mg / kg / day, between about 25 and 100 mg / kg / day, between about 25 and 250 mg / kg / day, or between about 50 and 250 mg / kg / day. In some aspects, the therapeutically effective amount of the MAO inhibitor is about 1 mg / kg / day, about 5 mg / kg / day, about 10 mg / kg / day, about 15 mg / kg / day, about 20 mg / kg / day, about 25mg / kg / day, about 30 mg / kg / day, about 40 mg / kg / day, about 50 mg / kg / day,about 60 mg / kg / day, about 70 mg / kg / day, about 80 mg / kg / day, about 90 mg / kg / day, or about 100 mg / kg / day.

[0020] In an additional embodiment, the invention provides a method for detecting colorectal cancer in a subject comprising administering a near-infrared conjugated monoamine oxidase A inhibitor (NMI) to the subject, measuring an amount of the NMI in a lower digestive tract of the subject, and determining that the subject has colorectal cancer if the amount of the NMI in the lower digestive tract of the subject is above a threshold level, or determining that the subject does not have colorectal cancer if the amount of the NMI in the lower digestive tract of the subject is below a threshold level, thereby detecting colorectal cancer in the subject.

[0021] In some aspects, the measuring comprises near-infrared fluorescence imaging. In some aspects, the method further comprises identifying a tumor in the lower digestive tract of the subject.

[0022] In another embodiment, the present invention provides a method of identifying a subject with colorectal cancer as a candidate for treatment with a monoamine oxidase (MAO) inhibitor comprising measuring MAO activity in a biological sample from the subject and classifying the biological sample as having an MAO activity above a threshold level as a likely responder to the MAO inhibitor, thereby identifying the subject as suitable for treatment with the MAO inhibitor, or classifying the biological sample as having an MAO activity below a threshold level as a likely- non responder to the MAO inhibitor, thereby identifying the subject as unsuitable for treatment with the MAO inhibitor; thereby identifying the subject with colorectal cancer as a candidate for treatment with the MAO inhibitor.

[0023] In some aspects, the biological sample comprises colorectal cancer cells. In some aspects, the biological sample is a tumor sample.

[0024] In some aspects, the measuring comprises a chemiluminescent assay.

[0025] In some aspects, the threshold level is about 10, about 15, about 20, about 25, about 30, about 35, about 40, about 45, about 50, about 55, about 60, about 65, about 70, about 75, about 80, about 85, about 90, about 95, or about 100 relative luminescent units per microgram protein per hour.

[0026] In some aspects, the measuring comprises RNA sequencing.

[0027] In another embodiments, the present invention provides a method of treating a cancer in a subject in need thereof comprising administering a therapeutically effective amount of a near-infrared conjugated monoamine oxidase inhibitor (NMI) and an immune checkpoint inhibitor to the subject, thereby treating the cancer.

[0028] In some aspects, the NMI is:or an alternate salt, solvate, tautomer, or zwitterion thereof.

[0029] In some aspects, the immune checkpoint inhibitor is selected from a programmed cell death 1 (PD-1) inhibitor, a programmed cell death ligand 1 (PD-L1) inhibitor, or a CTLA- 4 inhibitor.

[0030] In some aspects, the cancer is selected from lung cancer, breast cancer, pancreatic cancer, colorectal cancer, melanoma, acoustic neuroma, acute leukemia, acute lymphocytic leukemia, acute myelogenous leukemia, acute T-cell leukemia, basal cell carcinoma, bile duct carcinoma, bladder carcinoma, brain carcinoma, bronchial carcinoma, cervical carcinoma, chondrosarcoma, chordoma, choriocarcinoma, chronic leukemia, chronic lymphocytic leukemia, chronic myelogenous leukemia, colon carcinoma, craniopharyngioma, cystadenocarcinoma, diffuse large B-cell lymphoma, embryonic carcinoma, endometrial carcinoma, endothelioma, ependymoma, epithelial carcinoma, erythroleukemia, esophageal carcinoma, estrogen receptor positive breast carcinoma, primary thrombocythemia, ewing’s tumor, fibrosarcoma, follicular lymphoma, germ cell testicular carcinoma, glioma, glioblastoma, gliosarcoma, head and neck cancer, hemangioblastoma, liver cancer, hepatocellular carcinoma, hormone-insensitive prostate cancer, leiomyosarcoma, liposarcoma,lymphatic endothelial sarcoma, lymphatic sarcoma, lymphoblastic leukemia, lymphoma, T- cell or B-cell derived lymphoid malignancies, myeloid cancer, medulloblastoma, meningioma, mesothelioma, multiple myeloma, myxosarcoma, neuroblastoma, non-small cell lung cancer, oligodendroglioma, oral cancer, osteogenic sarcoma, ovarian cancer, papillary adenocarcinoma, papillary carcinoma, pinealoma, polycythemia vera, prostate cancer, rectal cancer, renal cell carcinoma, retinoblastoma, rhabdomyosarcoma, sebaceous adenocarcinoma, seminoma, skin cancer, small cell lung cancer, gastric cancer, squamous cell carcinoma, synovial sarcoma, sweat gland cancer, thyroid cancer, Waldenstrom’s macroglobulinemia, testicular tumor, uterine cancer, or wilms’ tumor.

[0031] In some aspects, the colorectal cancer comprises colorectal carcinoma, colorectal adenocarcinoma, colorectal melanoma, Dukes primary colorectal lymphoma, gastrointestinal stromal cancer, leiomyosarcoma, or colorectal carcinoid tumors. In some aspects, the colorectal cancer comprises colorectal carcinoma, colorectal adenocarcinoma, or metastatic colorectal cancer.

[0032] In some aspects, the therapeutically effective amount of the NMI is between about 1 and 250 mg / kg / day, between about 1 and 25 mg / kg / day, between about 5 and 25 mg / kg / day, between about 5 and 50 mg / kg / day, between about 10 and 50 mg / kg / day, between about 10 and 50 mg / kg / day, between about 10 and 100 mg / kg / day, between about 25 and 100 mg / kg / day, between about 25 and 250 mg / kg / day, or between about 50 and 250 mg / kg / day.

[0033] In some aspects, the therapeutically effective amount of the NMI is about 1 mg / kg / day, about 5 mg / kg / day, about 10 mg / kg / day, about 15 mg / kg / day, about 20 mg / kg / day, about 25mg / kg / day, about 30 mg / kg / day, about 40 mg / kg / day, about 50 mg / kg / day, about 60 mg / kg / day, about 70 mg / kg / day, about 80 mg / kg / day, about 90 mg / kg / day, or about 100 mg / kg / day.

[0034] In another embodiments, the present invention provides a method of treating colorectal cancer in a subject in need thereof comprising administering a therapeutically effective amount of a near-infrared conjugated monoamine oxidase A inhibitor (NMI) and a programmed cell death 1 (PD-1) inhibitor to the subject, thereby treating the colorectal cancer.

[0035] In some aspect, the NMI is:or an alternate salt, solvate, tautomer, or zwitterion thereof.

[0036] In some aspects, the colorectal cancer comprises colorectal carcinoma, colorectal adenocarcinoma, colorectal melanoma, Dukes primary colorectal lymphoma, gastrointestinal stromal cancer, leiomyosarcoma, or colorectal carcinoid tumors.

[0037] In some aspects, the colorectal cancer comprises colorectal carcinoma, colorectal adenocarcinoma, or metastatic colorectal cancer.

[0038] In some aspects, the therapeutically effective amount of the NMI is between about 1 and 250 mg / kg / day, between about 1 and 25 mg / kg / day, between about 5 and 25 mg / kg / day, between about 5 and 50 mg / kg / day, between about 10 and 50 mg / kg / day, between about 10 and 50 mg / kg / day, between about 10 and 100 mg / kg / day, between about 25 and 100 mg / kg / day, between about 25 and 250 mg / kg / day, or between about 50 and 250 mg / kg / day.

[0039] In some aspects, the therapeutically effective amount of the NMI is about 1 mg / kg / day, about 5 mg / kg / day, about 10 mg / kg / day, about 15 mg / kg / day, about 20 mg / kg / day, about 25mg / kg / day, about 30 mg / kg / day, about 40 mg / kg / day, about 50 mg / kg / day, about 60 mg / kg / day, about 70 mg / kg / day, about 80 mg / kg / day, about 90 mg / kg / day, or about 100 mg / kg / day.BRIEF DESCRIPTION OF THE DRAWINGS

[0040] FIGS. 1A-1D illustrate a dose-dependent inhibition of colony formation with various concentrations of NMI across three colorectal cancer (CRC) cell lines. FIG. 1A andFIG. IB show colony formation in HT 29 cells. FIG. 1C shows colony formation in SW620 cells. FIG. ID shows colony formation in HCT116 cells.

[0041] FIGS. 2A-2B. FIG. 2A is an image of 8-week-old NSG mice injected with HCT cells subcutaneously using IVIS in vivo imaging system. The image on the right indicates the localization of NMI in the tumors of the mice. FIG. 2B is an image of various organs of mice with an indication of the localization of NMI in various organs and a tumor.

[0042] FIGS. 3A-3E. FIG. 3A is a schematic diagram illustrating the experimental schedule for testing the in vivo efficacy of NMI, MAO A inhibitors (Clorgyline), MAO B inhibitors (Deprenyl), and MAO AB inhibitors (Phenelzine) in the MAO A / B high activity human patient derived xenograft (PDX) mouse animal model. FIG. 3B and FIG. 3C are graphs illustrating changes in tumor volume over 21 days after the treatment of the MAO A / B high activity PDX mouse animal model with the indicated treatments. FIG. 3D is an image of the PDX mouse at 24 hours post-NMI treatment using IVIS in vivo imaging system. FIG. 3E is an image of isolated organs of the PDX mouse animal model showing the NMI concentrations in various organs and a tumor using near-infrared fluorescence imaging.

[0043] FIGS. 4A-4C. FIG. 4A is a schematic diagram illustrating the experimental schedule for testing the in vivo efficacy of NMI, MAO A inhibitors (Clorgyline), MAO B inhibitors (Deprenyl), and MAO AB inhibitors (Phenelzine) in the MAO A / B low activity human patient derived xenograft (PDX) mouse animal model. FIG. 4B and FIG. 4C are graphs illustrating changes in tumor volume over 47 days after the treatment of the MAO A / B low activity PDX mouse animal model with the indicated treatments.

[0044] FIGS. 5A-5D. FIG. 5A and FIG. 5B are representative immunohistochemistry (IHC) images of tissue sections of tumors from the MAO A / B high-activity human patient- derived xenograft (PDX) mouse animal model. FIG. 5 A shows IHC images with CD31 staining of MAO A / B high-activity PDX tumor tissues. FIG. 5B shows IHC images with Ki67 staining of MAO A / B high-activity PDX tumor tissues. FIG. 5C is an image of MAO A / B high-activity PDX tumor tissues stained with a tumor invasion marker, MMP9. FIG. 5D is an image of MAO A / B high-activity PDX tumor tissues for apoptosis detection by TUNEL assay.

[0045] FIGS. 6A-6H. FIG. 6A is a schematic diagram illustrating the experimental schedule for testing in vivo efficacy of NMI, MAO A inhibitors, immune checkpoint inhibitor(anti-PD-1) in MSI MC38-C57BL / 6 syngeneic mice model system. FIG. 6B and FIG. 6C are graphs illustrating the efficacy of a decrease in tumor growth in the MSI MC38-C57BL / 6 model after treatment with the indicated regimen. FIG. 6D shows an analysis illustrating the statistical significance of the difference in decreasing tumor growth between the two indicated regimens. FIG. 6E shows graphs illustrating the tumor growth patterns of each mouse in the indicated treatment groups. FIG. 6F and FIG. 6G are graphs illustrating the probability of survival of the MSI MC38-C57BL / 6 model after treatment with the indicated regimen. FIG. 6H shows tables illustrating data related to the survival of the MSI MC38-C57BL / 6 model after treatment with the indicated regimen and a statistical analysis comparing the survival rate between treatment groups.

[0046] FIGS. 7A-7H. FIG. 7A is a schematic diagram illustrating the experimental schedule for testing in vivo efficacy of NMI, MAO A inhibitors, immune checkpoint inhibitor (anti-PD-1) in MSS CT26-BALB / c syngeneic mice model system. FIG. 7B and FIG. 7C are graphs illustrating the efficacy of a decrease in tumor growth in the MSS CT26-BALB / c model after treatment with the indicated regimen. FIG. 7D shows an analysis illustrating the statistical significance of the difference in decreasing tumor growth between the two indicated regimens. FIG. 7E shows graphs illustrating the tumor growth patterns of each mouse in the indicated treatment groups. FIG. 7F and FIG. 7G are graphs illustrating the probability of survival of the MSS CT26-BALB / c model after treatment with the indicated regimen. FIG. 7H shows tables illustrating data related to the survival of the MSS CT26-BALB / c model after treatment with the indicated regimen and a statistical analysis comparing the survival rate between treatment groups.DETAILED DESCRIPTION OF THE INVENTION

[0047] Before the present compositions and methods are described, it is to be understood that this invention is not limited to particular compositions, methods, and experimental conditions described, as such compositions, methods, and conditions may vary. It is also to be understood that the terminology used herein is for purposes of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only to the appended claims.

[0048] As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Thus, forexample, references to “the method” includes one or more methods, and / or steps of the type described herein which will become apparent to those persons skilled in the art upon reading this disclosure and so forth.

[0049] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0050] As used herein, the term “about” in association with a numerical value is meant to include any additional numerical value reasonably close to the numerical value indicated. For example, and based on the context, the value can vary up or down by 5-10%. For example, for a value of about 100, means 90 to 110 (or any value between 90 and 110).

[0051] As used herein and in the claims, the terms “comprising,” “containing,” and “including” are inclusive, open-ended and do not exclude additional unrecited elements, compositional components, or method steps. Accordingly, the terms “comprising” and “including” encompass the comparably more restrictive terms “consisting of’ and “consisting essentially of.”

[0052] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.

[0053] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the invention, it will be understood that modifications and variations are encompassed within the spirit and scope of the instant disclosure. The preferred methods and materials are now described.

[0054] The present invention is based on the seminal discovery that monoamine oxidase (MAO) inhibitors are effective for treating and diagnosing cancer. For example, it was determined herein that MAO activity mediates colorectal tumor growth. While many colorectal cancers exhibit multidrug resistances, it was discovered herein that MAO inhibitors, either alone or in combination with an immune checkpoint inhibitor such as a PD-1 -targetingantibody, can limit colorectal tumor growth irrespective of microsatellite stability and KRAS expression.

[0055] MAO A and MAO B activity are present in colorectal cancer cell lines, and their growth can be inhibited by a near-infrared monoamine oxidase A inhibitor (NMI), MAO A, and MAO B inhibitors. NMI targets tumors specifically and can be visualized noninvasively in vivo and ex vivo. High- and low-MAO activity human patient-derived xenograft (PDX) animal models were compared. Mouse tumors from high MAO PDX grew faster, larger, and had shorter survival compared to those from low MAO PDX. NMI, MAO A inhibitors (e.g., clorgyline), MAO AB inhibitors (phenelzine), and MAO B inhibitors (dephenyl) were shown to effectively inhibit tumor growth, indicating that NMI is an effective new treatment for colorectal cancer and that MAO A and B inhibitors can be repurposed for colorectal cancer treatment. NMI and clorgyline have similar mechanisms of action in which they reduce proliferation, angiogenesis, invasion, and increased apoptosis. In immune checkpoint inhibitor (ICI)-responsive MSI colorectal cancer cells (MC38), NMI alone or in combination with ICI anti-PDl reduces tumor growth and increases survival. This will be a potential new treatment for the subset of 20-30% of MSI-H patients that do not respond to current immunotherapy. In a less responsive MSS colorectal cancer cell CT26 mouse model, NMI enhanced the effects of the ICI anti-PDl antibody in reducing tumor growth and increasing survival. Targeting PD1 using ICI increases immunoediting in the tumor microenvironment. The less immunogenic model CT26 does not show a pronounced immunoediting effect post-ICI treatment. MSS CRC does not benefit from immunotherapy treatment, emphasizing the importance of finding new drugs targeting the immune microenvironment and increasing the efficacy of known ICIs. NMI combined with anti-PDl will fill this unmet need.

[0056] The implications of this invention, however, extend far beyond the realm of colorectal cancers. Through extensive research and application, it has become evident that the effectiveness of monoamine oxidase (MAO) inhibitors in mediating tumor growth is not limited to colorectal cancer alone. This discovery paves the way for the potential application of MAO inhibitors in a wide array of cancer types, including those characterized by microsatellite instability (MSI) or microsatellite stability (MSS). The integration of MAO inhibitors with immune checkpoint inhibitors (ICIs) further accentuates their potential, offering a dual approach that could revolutionize the treatment landscape for cancers traditionally resistant to ICIs. The universal presence of MAO A and MAO B activities across various cancercell lines suggests that the therapeutic benefits of NMI, MAO A, and MAO B inhibitors, in combination with ICIs, could be harnessed for the treatment of diverse cancers. This approach not only targets the fundamental processes driving cancer progression but also modulates the immune environment to enhance the efficacy of ICIs. Preliminary studies and extrapolations based on the underlying mechanisms of action indicate that this invention holds promise for combating an extensive spectrum of cancers, thereby offering a universal approach to cancer therapy and diagnosis. The broader applicability of combining MAO inhibitors with ICIs is underpinned by the fundamental role of MAO activity in cancer cell proliferation and survival, irrespective of the cancer type or microsatellite status. This synergistic combination presents a versatile and powerful tool in the fight against cancer, making this invention a significant leap forward in the development of comprehensive cancer therapies.

[0057] NMI in combination with anti-PD 1 also exhibited potency against the ICI insensitive cells (e.g., CT26). Clorgyline and NMI improved the effect of ICI in MC38 model by reducing tumor growth. In the CT26 model, clorgyline alone or in combination with ICI was equally effective in reducing tumor growth and increasing survival of the host. These results show that MAO A and MAO B inhibitors can be used for colorectal cancer treatment, and in particular that NMI is a new cancer immune therapy and non-invasive diagnosis tool which meets unmet needs for colorectal cancer diagnosis and treatment.

[0058] Leveraging these discoveries, in one embodiment, the invention provides a method of treating colorectal cancer in a subject in need thereof comprising administering a therapeutically effective amount of the monoamine oxidase (MAO) inhibitor to the subject, thereby treating the colorectal cancer. As nonlimiting examples, the MAO inhibitor can be clorgyline, a near-infrared conjugated monoamine oxidase A inhibitor (NMI), deprenyl, selegiline, rasagiline, pargyline, ifemelane, moclobemide, pirlindole, toloxatone, minaprine, phenelzine, tranylcypromine, phenelzine, tranylcypromine. As nonlimiting examples, the therapeutic effective amount of the MAO inhibitor can be between about 1 and 250 mg / kg / day, between about 1 and 25 mg / kg / day, between about 5 and 25 mg / kg / day, between about 5 and 50 mg / kg / day, between about 10 and 50 mg / kg / day, between about 10 and 50 mg / kg / day, between about 10 and 100 mg / kg / day, between about 25 and 100 mg / kg / day, between about 25 and 250 mg / kg / day, or between about 50 and 250 mg / kg / day.

[0059] In another embodiments, the invention provides a method of treating a cancer in a subject in need thereof including administering a therapeutically effective amount of a nearinfrared conjugated monoamine oxidase inhibitor (NMI) and an immune checkpoint inhibitor to the subject, thereby treating the cancer. As nonlimiting examples, the immune checkpoint inhibitor can be a programmed cell death 1 (PD-1) inhibitor, a programmed cell death ligand 1 (PD-L1) inhibitor, or a CTLA-4 inhibitor. As nonlimiting examples, the immune checkpoint inhibitor can be nivolumab (PD-1 inhibitor), pembrolizumab (PD-1 inhibitor), cemiplimab (PD-1 inhibitor), atezolizumab (PD-L1 inhibitor), avelumab (PD-L1 inhibitor), durvalumab (PD-L1 inhibitor), ipilimumab (CTLA-4 inhibitor) or tremelimumab (CTLA-4 inhibitor) or any combination thereof. As nonlimiting examples, the cancer can be lung cancer, breast cancer, pancreatic cancer, colorectal cancer, melanoma, acoustic neuroma, acute leukemia, acute lymphocytic leukemia, acute myelogenous leukemia, acute T-cell leukemia, basal cell carcinoma, bile duct carcinoma, bladder carcinoma, brain carcinoma, bronchial carcinoma, cervical carcinoma, chondrosarcoma, chordoma, choriocarcinoma, chronic leukemia, chronic lymphocytic leukemia, chronic myelogenous leukemia, colon carcinoma, craniopharyngioma, cystadenocarcinoma, diffuse large B-cell lymphoma, embryonic carcinoma, endometrial carcinoma, endothelioma, ependymoma, epithelial carcinoma, erythroleukemia, esophageal carcinoma, estrogen receptor positive breast carcinoma, primary thrombocythemia, Ewing’s tumor, fibrosarcoma, follicular lymphoma, germ cell testicular carcinoma, glioma, glioblastoma, gliosarcoma, head and neck cancer, hemangioblastoma, liver cancer, hepatocellular carcinoma, hormone-insensitive prostate cancer, leiomyosarcoma, liposarcoma, lymphatic endothelial sarcoma, lymphatic sarcoma, lymphoblastic leukemia, lymphoma, T- cell or B-cell derived lymphoid malignancies, myeloid cancer, medulloblastoma, meningioma, mesothelioma, multiple myeloma, myxosarcoma, neuroblastoma, non-small cell lung cancer, oligodendroglioma, oral cancer, osteogenic sarcoma, ovarian cancer, papillary adenocarcinoma, papillary carcinoma, pinealoma, polycythemia vera, prostate cancer, rectal cancer, renal cell carcinoma, retinoblastoma, rhabdomyosarcoma, sebaceous adenocarcinoma, seminoma, skin cancer, small cell lung cancer, gastric cancer, squamous cell carcinoma, synovial sarcoma, sweat gland cancer, thyroid cancer, Waldenstrom’s macroglobulinemia, testicular tumor, uterine cancer, or wilms’ tumor.

[0060] In another embodiments, the invention provides a method of treating colorectal cancer in a subject in need thereof comprising administering a therapeutically effective amountof a near-infrared conjugated monoamine oxidase A inhibitor (NMI) and a programmed cell death 1 (PD-1) inhibitor to the subject, thereby treating the colorectal cancer. As nonlimiting examples, the colorectal cancer can be colorectal carcinoma, colorectal adenocarcinoma, colorectal melanoma, Dukes primary colorectal lymphoma, gastrointestinal stromal cancer, leiomyosarcoma, or colorectal carcinoid tumors.

[0061] The MAO inhibitor can optionally be coupled to a near infrared dye by a linker. As disclosed herein, the near infrared dye can increase the potency and selective cytotoxicity of the MAO inhibitor against colorectal cancer. The near infrared dye can be directly coupled to the MAO inhibitor or can be coupled to the MAO inhibitor by a linker. In some aspectss, the near infrared dye is IR-783, IR-780, IR-786, or MHI-148.

[0062] The MAO inhibitor coupled to the near-infrared dye is clorgyline, in which aspects the complex can be referred to as a near-infrared conjugated monoamine oxidase A inhibitor (NMI). This bifunctional system has the NIR imaging capability for diagnosis as well therapeutic activity to specifically target colorectal cancer. In a particular aspect, the NMI is:or an alternate salt (e.g., paired with a fluoride, chloride, iodide, mesyl, tosyl, or nitrate counterion), solvate, tautomer, or zwitterion thereof.

[0063] As further disclosed herein, an NMI can enable non-invasive cancer diagnostics.Many cancer cells, such as colorectal cancer cell line HCT116 implanted tumors, exhibitenhanced NMI uptake relative to non-cancerous cells, leading the NMI to partition to regions with high cancer cell densities. Following NMI administration, local cancer cell density can be determined by imaging the near-infrared dye of the NMI (e.g., with near-infrared fluorescence imaging). The imaging can identify individual tumors, aggregate tumor burden, cancer stage and progression, cancer spread, or a combination thereof. The imaging can also provide intraoperative visualization margins during surgery. The imaging can be performed directly on a subject, or on a biopsy sample obtained from the subject (e.g., a colon biopsy).

[0064] The following examples are provided to further illustrate the embodiments of the present invention but are not intended to limit the scope of the invention. While they are typical of those that might be used, other procedures, methodologies, or techniques known to those skilled in the art may alternatively be used.EXAMPLES

[0065] Example 1

[0066] Testing of NMI on PDX mouse models for CRC therapy.

[0067] This Example illustrates MAO A and B expression and activity in CRC cell lines, as well as the effect of NMI on CRC cell viability and proliferation. MAO A and B activities were detected in several CRC cell lines, including HCT 116, LoVo, DLD 1 (MSI, KRAS mutant), Caco2 (MSS, KRAS wild type), SW620 (MSS, KRAS mutant), HT29 (MSS, KRAS wild type, BRAF mutant), MC38 (MSI, KRAS wild type), and CT26 (MSS, KRAS mutant). It was observed that NMI could significantly diminish their proliferation.

[0068] The study utilized a patient-derived xenograft (PDX) platform, which accurately reflects the patient’s molecular profile, to generate two distinct PDX mouse models based on MAO A / B activity levels. By implanting tumor samples with either high or low MAO A / B activity into 6-8 week old NSG mice, the resulting MAO low PDX mouse model exhibited significantly reduced tumor growth rates compared to its MAO high counterpart (210 days vs. 66 days). This difference underscores the influence of MAO A / B activity on CRC development.

[0069] To further assess the impact of NMI and MAO A / B inhibitors on tumor growth, the study transplanted tumors from Fl generation PDX mice into a second cohort of 25 NSG mice. These mice were then subjected to a 21 -day treatment regimen involving intraperitoneal injections of: 1) vehicle, 2) MAO A inhibitor (clorgyline), 3) near-infrared dye-conjugatedMAO A inhibitor (NMI), 4) MAO B inhibitor (deprenyl), and 5) a combined MAO A & B inhibitor (phenelzine). The MAO high PDX group displayed a significant reduction in tumor volume following treatment with MAO A inhibitors (clorgyline, p=0.009), NMI (p=0.053), and the MAO B inhibitor deprenyl (p=0.022), alongside a notable decrease in angiogenesis and cell proliferation markers (CD31 and Ki67). Moreover, increased apoptosis was observed in tumors treated with clorgyline and NMI, as evidenced by TUNEL assay. RNA sequencing identified 50 and 171 differentially expressed genes (DEGs) in tumors treated with clorgyline and NMI, respectively, compared to controls (padj <0.05, |fold change] >=1.5).

[0070] Ingenuity Pathway Analysis of the sequencing data pointed to alterations in several key pathways, including oxidative phosphorylation, sirtuin signaling, estrogen receptor signaling, and mitochondrial function. Remarkably, NMI demonstrated comparable efficacy to clorgyline, albeit at tenfold lower doses, without inducing toxicity in the MAO high PDX mouse model. No significant differences in tumor sizes were observed among the treatment groups in the MAO low PDX cohort.

[0071] The comprehensive CRC PDX studies underscore the critical role of MAO A and B in tumor growth, presenting them as promising therapeutic targets. Comparative analyses through immunohistochemistry (IHC) and RNA sequencing (RNA-seq) indicated that MAO A inhibitors and NMI not only share mechanistic pathways but also that NMI is more effective than clorgyline, offering additional diagnostic utility.

[0072] The study further examined MAO A and B expression levels in CRC cell lines through RT-qPCR, as detailed in Table 1. The protocol included extracting total RNA, synthesizing the first strand cDNA, and conducting quantitative PCR assays with SYBR green on a CFX 96 Real-time PCR system, employing specific primers for MAO A and MAO B.

[0073] Table 1 summarizes MAO A and B expression and activity in CRC cell lines. The expression profile of MAO A and B at transcription level in CRC cell lines samples was evaluated using RT qPCR. The catalytic activity of MAO A and B was determined using MAO Gio assay.

[0074] A comparative study across human and mouse CRC cell lines, selected based on clinically relevant molecular characteristics (MSI / MSS status, RAS, and BRAF V600E mutation status), aimed to elucidate any correlation between these features and MAO A / B expression and activity. The results, as presented in Table 1, revealed distinct patterns of MAO A and B expression among the cell lines, with HT29 showing the highest MAO A expression and HCT116 the highest MAO B expression. Notably, both MAO A and B activities were pronounced in HT29 cells and the two mouse cell lines, suggesting that MAO A / B expression and activity are independent of the MSI / MSS status or RAS mutation, highlighting their potential as independent markers or therapeutic targets in CRC.

[0075] Effect of NMI on CRC cell viability.

[0076] A standard MTT assay was utilized to investigate the impact of NMI on CRC cell viability. CRC cells, seeded at a density of 2,000 cells per well in 96-well plates, were treated 24 hours post-seeding with various concentrations of NMI, while DMSO was used as the control, over a 72-hour period. Viability of the cells treated with inhibitors was quantified in accordance with the manufacturer’s protocol for the MTT assay. The results highlighted that NMI exhibited significant anti-cancer activity across diverse human cell lines, irrespective of their baseline molecular characteristics. Specifically, NMI showed the greatest effectiveness in the HCT116 cell line, with an IC50 value of 8.9pM, and was least effective in the Caco2 cellline (IC50: 23.01pM). In comparison between mouse CRC cell lines, NMI was found to be more efficacious in MC38 than in CT26, as detailed in Table 2.

[0077] Table 2 describes an efficacy of NMI (growth inhibition ICso) on CRC cell lines using MTT assay.

[0078] Effect of NMI on CRC cell proliferation.

[0079] A colony assay was conducted to examine NMI’s effect on CRC cell proliferation. Cells were plated at a density of 500 cells per well in six-well plates. After a period of 24 hours, treatments with NMI at concentrations of 5pM, lOpM, and 20pM were administered, with DMSO-treated cells serving as the control. The formation of colonies, occurring between 7-10 days depending on the cell line, was observed. Colonies were fixed with 100% methanol for 20 minutes, then stained with 0.5% crystal violet in 25% methanol for 5 minutes at room temperature. After rinsing off the excess dye, plates were inverted to dry overnight. Colonies, identified as non-overlapping clusters of at least 50 cells, were analyzed under a bright-field microscope, photographed, and counted.

[0080] Significant dose- dependent inhibition of colony formation was observed across three CRC cell lines with varying molecular backgrounds, as illustrated in FIG. 1A to FIG. ID. The 5pM concentration of NMI significantly impacted cell proliferation, most notably in the SW620 cell line (FIG. 1C), and had the least effect on the HT29 cell line (FIG. 1A and FIG. IB). No colonies were formed in the SW620 (FIG. 1C) and HCT116 (FIG. ID) cell lines at concentrations of 10 M and 20pM NMI. These findings, consistent with the MTT assay results, confirm that the efficacy of NMI in inhibiting cell proliferation is independent of theMSI / MSS status or RAS mutation, underscoring its potential as a broad-spectrum anti-cancer agent.

[0081] Example 2

[0082] In vivo efficacy and safety of NMI and MAO inhibitors in CRC.

[0083] This Example illustrates the efficacy and safety of NMI and MAO inhibitors on CRC treatment in human patient derived xenograft (PDX) mouse models. PDX mouse models resemble human cancer biology and predict drug response more accurately than their predecessor cell line models. It has also been demonstrated that the molecular and histopathological profiles of PDX mouse models mimic features of the original tumor from which they were derived, including the retention of aberrations in key driver genes and signaling pathways. To investigate whether specific molecular subtypes of human CRC are more sensitive to targeting the MAO, two PDX mouse models were selected based on MAO A and B activity. Establishing PDX mouse models with high or low MAO A / B activity involved implanting patient’s tumor samples (F0 generation) with high MAO A / B activity (MAO high) or low MAO A / B activity (MAO low) in 8-week-old NSG mice (Fl generation). HCT116 cells were injected subcutaneously in 8-week-old NSG mice. Once the tumors reached 1 cm3, mice were injected with 5 mg / kg. Twenty -four hours post-treatment, mice were imaged using the IVIS system, showing that NMI localized in the tumors in vivo (FIG. 2A). Mice were euthanized, and isolated tumors and organs were imaged ex vivo, revealing significant accumulation of NMI-specific fluor in tumors compared to other organs, suggesting that NMI targets specifically to the tumors. In FIG. 2, it is demonstrated that NMI targets specifically to the tumor, can be used for noninvasive diagnosis, and to monitor the progression of cancer.

[0084] MAO A / B high activity PDX mouse model

[0085] The Fl MAO high PDX mouse model showed substantially faster tumor growth rates compared to the MAO low PDX mouse model (66 days vs. 210 days), suggesting MAO activity increases CRC tumor formation (FIG. 3A and FIG. 4A). F2 generation PDX tumor tissues were used for drug efficacy experiments. The MAO high PDX cohort was given treatment for 21 days. Most of the mice reached the endpoint by the 18th day. Tumor growth (volume) was significantly reduced in all the treatment groups compared to control. On the 18th day of treatment, the MAO high PDX cohort showed significant reduction in tumor volume in mice treated with MAO A inhibitors cl orgyline (p=0.009); NMI (p=0.053) and MAO B inhibitor deprenyl (p=0.022), phenelzine (p= 0.097) when compared to control. The NMIshowed the same efficacy with no toxicity compared to clorgyline even at 10 times lower dose in the MAO high PDX mouse model (FIG. 3B and FIG. 3C). In vivo imaging of the mice, 24 hours post NMI treatment, showed that NMI specifically localizes in tumors (FIG. 3D). Ex vivo imaging of isolated organs showed NMI concentrated mostly in tumors followed by the intestine, colon, and stomach (FIG. 3E).

[0086] MAO A / B low activity PDX mouse model

[0087] MAO low activity tumors grew significantly slower compared to high activity (FIG. 4A). No significant difference in tumor size was found among treatment groups in the MAO low PDX cohort even after 28 days of treatment (FIG. 4B and FIG. 4C). Tumors reached endpoints between day 49 and 108 depending on the treatment groups, while in the high MAO activity PDX cohort, mice reached the endpoint by day 19 of the treatments (Table 3). The clorgyline group was euthanized at day 28 of the treatment due to signs of toxicity. Drug injections were extended to 28 days to observe any treatment effect. The MAO low activity characteristics of the tumor had a dominant effect on tumor growth rather than treatments. Interestingly, no additive or synergistic effect of treatments was seen with the MAO low activity trait of the tumor. The results of testing the in vivo efficacy of NMI, MAO A inhibitors (Clorgyline), MAO B inhibitors (Deprenyl), and MAO AB inhibitor (Phenelzine) in MAO A / B high and low activity PDX mouse models demonstrate that MAO A and B activity can be used as a biomarker for CRC progression.

[0088] Table 3 summarizes a comparison of high MAO PDX versus low MAO PDX

[0089] Measurement of apoptosis, cell proliferation, angiogenesis, and tumor invasion markers in high MAO A / B activity PDX mouse model

[0090] MAO activity has been correlated with tumor growth and progression, angiogenesis, and invasion. Examining the mechanism of action of NMI in high MAO activity tumors involved immunostaining the tumor sections with markers for angiogenesis, cell proliferation, invasion, and apoptosis. Significant reductions in angiogenesis marker CD31 staining of tumor tissues were observed in mice treated with clorgyline and NMI (FIG. 5A). Additionally, Ki-67 staining demonstrated a considerable decrease in cell proliferation (FIG. 5B), and a decrease in invasion marker MMP9 staining (FIG. 5C) followed drug treatments. TUNEL assay (FIG. 5D) exhibited an increase in apoptosis in tumors treated with clorgyline and NMI.

[0091] Example 3

[0092] In vivo efficacy of NMI, MAO A inhibitors, and immune checkpoint inhibitor.

[0093] This Example illustrates the in vivo efficacy of NMI and the MAO A inhibitor clorgyline, either as monotherapies or in combination with the immune checkpoint inhibitor (ICI) anti-PD-1, across two colon cancer models: MC38 (MSI model) and CT26 (MSS model) in syngeneic mice.

[0094] MC38 MSI colon cancer model

[0095] ICIs have shown effectiveness in MSI-H patients, though a subset exhibits innate resistance, underscoring the need for actionable strategies to enhance ICI efficacy. The effects of NMI and clorgyline, alone or in combination with anti-PD-1, were assessed using the MSI MC38-C57BL / 6 syngeneic mouse model (FIG. 6A). Addressing resistance seen in some MSI- H patients to ICIs, the study explored strategies to boost ICI efficacy. In the MC38-C57BL / 6 syngeneic mouse model, clorgyline alone attenuated tumor growth comparably to anti-PD-1 (p=0.0176). The combination of clorgyline with anti-PD-1 suggested a trend towards increased efficacy over the control (p=0.0009) and clorgyline monotherapy (p=0.0089), although it did not significantly exceed anti-PD-1 alone in tumor reduction (FIG. 6B and FIG. 6D). Surprisingly, NMI combined with anti-PD-1 significantly diminished tumor growth beyond the control group (p=0.0019) and NMI alone (p=0.0215), correlating with improved survival outcomes (FIG. 6C and FIG. 6D). Unexpectedly, NMI proved more effective than clorgyline at a tenfold lower concentration, without inducing toxicity, showcasing a significant breakthrough in efficacy and safety. The variations in tumor growth among individual responders and non-responders are detailed in FIG. 6E.

[0096] Survival analysis revealed that combining cl orgy line with anti-PD-1 notably increased survival rates compared to clorgyline alone and the control group (p=0.0010 and p=0.0104, respectively), albeit not outperforming anti-PD-1 monotherapy (FIG. 6F). Conversely, the combination of NMI and anti-PD-1 remarkably enhanced survival over either NMI or anti-PD-1 used singly (p=0.0021) (FIG. 6G). Median survival significantly favored the clorgyline + anti-PD-1 combination over the vehicle (p=0.0023), clorgyline alone (p=0.0497), and NMI alone (p=0.0448). Similarly, NMI + anti-PD-1 significantly extended median survival over the vehicle (p=0.0008), clorgyline alone (p=0.0059), and NMI alone (p=0.0041) (FIG. 6H), though the difference between NMI + anti-PD-1 and clorgyline + anti- PD-1 was not significant.

[0097] In summary, clorgyline did not enhance treatment outcomes. Anti-PDl therapy was more effective as a standalone treatment than when combined with clorgyline. However, the combination of NMI and anti-PDl outperformed other treatment regimens in terms of tumor growth inhibition and survival enhancement. Clorgyline exhibited toxicity at its effective dose (50 mg / kg), while NMI remained effective and non-toxic even at a tenfold lower dose (5 mg / kg). Although the clorgyline and anti-PDl combination showed some promise in reducing tumor growth compared to the control (p=0.0009) and clorgyline monotherapy (p=0.0089), it was less effective than anti-PDl alone and did not improve survival outcomes. Notably, the combination of NMI with anti-PDl significantly reduced tumor growth compared to both the control (p=0.0019) and NMI alone (p=0.0215), mirroring the survival benefits. The most surprising outcome was the effectiveness of NMI at a substantially lower concentration compared to clorgyline, without any observed toxicity.

[0098] CT26 MSS colon cancer model

[0099] Given that MSS CRC tumors do not typically benefit from immunotherapy, there is a pressing need for novel therapeutics to either augment ICI efficacy in this patient subset or target the immune microenvironment. To explore the efficacy of NMI in MSS tumors, the MSS CT26-BALB / c syngeneic mouse model was employed (FIG. 7A). Clorgyline treatment, both alone and in combination with anti-PD-1, reduced tumor size without significant differences between the combination and monotherapy groups (FIG. 7B and FIG. 7D). NMI combined with anti-PD-1 showed a reduction in tumor size compared to the control (p=0.0193) and anti- PD-1 alone (p=0.0272), though NMI monotherapy did not significantly outperform anti-PD-1 (FIG. 7C and FIG. 7D)

[0100] Clorgyline monotherapy or in combination with anti-PD-1 increased survival, with no observed additive or synergistic effect when combined with anti-PD-1 (FIG. 7F). NMI plus anti-PD-1 treatment showed a non-significant trend toward increased survival over control and anti-PD-1 alone (FIG. 7G). NMI monotherapy did not confer a survival advantage. Median survival was improved with NMI + anti-PD-1 compared to control (FIG. 7H). Individual responses are illustrated in FIG. 7E.

[0101] In summary, the combination of clorgyline and anti-PDl did not offer additional benefits over clorgyline alone, showing no significant impact on tumor growth or overall survival. Conversely, NMI, when used in conjunction with anti-PDl, resulted in a notable decrease in tumor size and improved survival rates. This was evidenced by a significant reduction in tumor size compared to the control group (p=0.0193) and to anti-PDl treatment alone (p=0.0272). Moreover, an unexpected finding was that NMI, even at a dose ten times lower than that of clorgyline, was more effective in reducing tumor growth and enhancing survival when combined with anti-PDl.

[0102] The study conclusively demonstrates NMI’s superior efficacy in CRC treatment when compared to the existing MAO A inhibitor, particularly in combination with anti-PDl therapy. The unexpected potency of NMI at lower doses highlights its potential as a more effective and safer alternative in CRC therapy. This discovery suggests that NMI’s targeted delivery could significantly alter the immune tumor microenvironment, offering a promising avenue for future research and potential therapeutic applications.

[0103] Although the invention has been described with reference to the above examples, it will be understood that modifications and variations are encompassed within the spirit and scope of the invention. Accordingly, the invention is limited only by the following claims.

Claims

What is claimed is:

1. A method of treating colorectal cancer in a subject in need thereof comprising administering a therapeutically effective amount of a monoamine oxidase (MAO) inhibitor to the subject, thereby treating the colorectal cancer.

2. The method of claim 1 , wherein the MAO inhibitor is selected from a MAO A inhibitor, a MAO B inhibitor, a MAO A / B inhibitor, or a combination thereof.

3. The method of claim 2, wherein the method comprises administering the MAO A inhibitor to the subject.

4. The method of claim 3, wherein the MAO A inhibitor is a near-infrared conjugated monoamine oxidase A inhibitor (NMI), clorgyline, bifemelane, moclobemide, pirlindole, toloxatone, minaprine, or a combination thereof.

5. The method of claim 4, wherein the MAO A inhibitor is NMI or clorgyline.

6. The method of claim 5, wherein the MAO A inhibitor is NMI.

7. The method of claim 6, wherein the NMI isor an alternate salt, solvate, tautomer, or zwitterion thereof.

8. The method of claim 2, wherein the method comprises administering the MAO B inhibitor to the subject.

9. The method of claim 8, wherein the MAO B inhibitor is deprenyl, selegiline, rasagiline, pargyline, or a combination thereof.

10. The method of claim 9, wherein the MAO B inhibitor is deprenyl.

11. The method of claim 2, wherein the method comprises administering the MAO A / B inhibitor to the subject.

12. The method of claim 11, wherein the MAO A / B inhibitor is phenelzine, tranylcypromine, or a combination thereof.

13. The method of claim 2, wherein the method comprises administering the MAO A inhibitor and the MAO B inhibitor to the subject.

14. The method of claim 13, wherein the MAO A inhibitor is NMI.

15. The method of claim 13, wherein the MAO B inhibitor is deprenyl.

16. The method of claim 1, wherein the colorectal cancer comprises colorectal carcinoma, colorectal adenocarcinoma, colorectal melanoma, Dukes primary colorectal lymphoma, gastrointestinal stromal cancer, leiomyosarcoma, or colorectal carcinoid tumors. In one aspect, the colorectal cancer comprises colorectal carcinoma, colorectal adenocarcinoma, or metastatic colorectal cancer.

17. The method of claim 16, wherein the colorectal cancer comprises colorectal carcinoma, colorectal adenocarcinoma, or metastatic colorectal cancer.

18. The method of claim 1, wherein the cancer exhibits MAO A activity, MAO B activity, or a combination thereof.

19. The method of claim 1, further comprising administering an immune checkpoint inhibitor.

20. The method of claim 19, wherein the immune checkpoint inhibitor is selected from a programmed cell death 1 (PD-1) inhibitor, a programmed cell death ligand 1 (PD-L1) inhibitor, or a CTLA-4 inhibitor.

21. The method of claim 1, wherein the therapeutically effective amount is between about 1 and 250 mg / kg / day, between about 1 and 25 mg / kg / day, between about 5 and 25 mg / kg / day, between about 5 and 50 mg / kg / day, between about 10 and 50 mg / kg / day, between about 10 and 50 mg / kg / day, between about 10 and 100 mg / kg / day, between about 25 and 100 mg / kg / day, between about 25 and 250 mg / kg / day, or between about 50 and 250 mg / kg / day.

22. The method of claim 1, wherein the therapeutically effective amount is about 1 mg / kg / day, about 5 mg / kg / day, about 10 mg / kg / day, about 15 mg / kg / day, about 20 mg / kg / day, about 25mg / kg / day, about 30 mg / kg / day, about 40 mg / kg / day, about 50 mg / kg / day, about 60 mg / kg / day, about 70 mg / kg / day, about 80 mg / kg / day, about 90 mg / kg / day, or about 100 mg / kg / day.

23. A method for detecting colorectal cancer in a subject comprising administering a nearinfrared conjugated monoamine oxidase A inhibitor (NMI) to the subject, measuring an amount of the NMI in a lower digestive tract of the subject, and i) determining that the subject has colorectal cancer if the amount of the NMI in the lower digestive tract of the subject is above a threshold level, or ii) determining that the subject does not have colorectal cancer if the amount of the NMI in the lower digestive tract of the subject is below a threshold level, thereby detecting colorectal cancer in the subject.

24. The method of claim 23, wherein the measuring comprises near-infrared fluorescence imaging.

25. The method of claim 23, wherein further comprising identifying a tumor in the lower digestive tract of the subject.

26. A method of identifying a subject with colorectal cancer as a candidate for treatment with a monoamine oxidase (MAO) inhibitor comprising measuring MAO expression or activity in a biological sample from the subject and i) classifying the biological sample as having an MAO expression or activity above a threshold level as a likely responder to the MAO inhibitor, thereby identifying the subject as suitable for treatment with the MAO inhibitor, or ii) classifying the biological sample as having an MAO expression or activity below a threshold level as a likely-non responder to the MAO inhibitor, thereby identifying the subject as unsuitable for treatment with the MAO inhibitor; thereby identifying the subject with colorectal cancer as a candidate for treatment with the MAO inhibitor.

27. The method of claim 26, wherein the biological sample comprises colorectal cancer cells.

28. The method of claim 27, wherein the biological sample is a tumor sample.

29. The method of claim 26, wherein the measuring comprises a chemiluminescent assay.

30. The method of claim 26, wherein the threshold activity level is about 10, about 15, about 20, about 25, about 30, about 35, about 40, about 45, about 50, about 55, about 60, about 65, about 70, about 75, about 80, about 85, about 90, about 95, or about 100 relative luminescent units per microgram protein per hour.

31. The method of claim 26, wherein the measuring comprises RNA sequencing.

32. A method of treating a cancer in a subject in need thereof comprising administering a therapeutically effective amount of a near-infrared conjugated monoamine oxidase inhibitor (NMI) and an immune checkpoint inhibitor to the subject, thereby treating the cancer.

33. The method of claim 32, wherein the NMI isor an alternate salt, solvate, tautomer, or zwitterion thereof.

34. The method of claim 32, wherein the immune checkpoint inhibitor is selected from a programmed cell death 1 (PD-1) inhibitor, a programmed cell death ligand 1 (PD-L1) inhibitor, or a CTLA-4 inhibitor.

35. The method of claim 32, wherein the cancer is selected from lung cancer, breast cancer, pancreatic cancer, colorectal cancer, melanoma, acoustic neuroma, acute leukemia, acute lymphocytic leukemia, acute myelogenous leukemia, acute T-cell leukemia, basal cell carcinoma, bile duct carcinoma, bladder carcinoma, brain carcinoma, bronchial carcinoma, cervical carcinoma, chondrosarcoma, chordoma, choriocarcinoma, chronic leukemia, chroniclymphocytic leukemia, chronic myelogenous leukemia, colon carcinoma, craniopharyngioma, cystadenocarcinoma, diffuse large B-cell lymphoma, embryonic carcinoma, endometrial carcinoma, endothelioma, ependymoma, epithelial carcinoma, erythroleukemia, esophageal carcinoma, estrogen receptor positive breast carcinoma, primary thrombocythemia, ewing’s tumor, fibrosarcoma, follicular lymphoma, germ cell testicular carcinoma, glioma, glioblastoma, gliosarcoma, head and neck cancer, hemangioblastoma, liver cancer, hepatocellular carcinoma, hormone-insensitive prostate cancer, leiomyosarcoma, liposarcoma, lymphatic endothelial sarcoma, lymphatic sarcoma, lymphoblastic leukemia, lymphoma, T-cell or B-cell derived lymphoid malignancies, myeloid cancer, medulloblastoma, meningioma, mesothelioma, multiple myeloma, myxosarcoma, neuroblastoma, non-small cell lung cancer, oligodendroglioma, oral cancer, osteogenic sarcoma, ovarian cancer, papillary adenocarcinoma, papillary carcinoma, pinealoma, polycythemia vera, prostate cancer, rectal cancer, renal cell carcinoma, retinoblastoma, rhabdomyosarcoma, sebaceous adenocarcinoma, seminoma, skin cancer, small cell lung cancer, gastric cancer, squamous cell carcinoma, synovial sarcoma, sweat gland cancer, thyroid cancer, Waldenstrom’s macroglobulinemia, testicular tumor, uterine cancer, or wilms’ tumor.

36. The method of claim 35, wherein the colorectal cancer comprises colorectal carcinoma, colorectal adenocarcinoma, colorectal melanoma, Dukes primary colorectal lymphoma, gastrointestinal stromal cancer, leiomyosarcoma, or colorectal carcinoid tumors.

37. The method of claim 36, wherein the colorectal cancer comprises colorectal carcinoma, colorectal adenocarcinoma, or metastatic colorectal cancer.

38. The method of claim 32, wherein the therapeutically effective amount is between about 1 and 250 mg / kg / day, between about 1 and 25 mg / kg / day, between about 5 and 25 mg / kg / day, between about 5 and 50 mg / kg / day, between about 10 and 50 mg / kg / day, between about 10 and 50 mg / kg / day, between about 10 and 100 mg / kg / day, between about 25 and 100 mg / kg / day, between about 25 and 250 mg / kg / day, or between about 50 and 250 mg / kg / day.

39. The method of claim 32, wherein the therapeutically effective amount is about 1 mg / kg / day, about 5 mg / kg / day, about 10 mg / kg / day, about 15 mg / kg / day, about 20 mg / kg / day, about 25mg / kg / day, about 30 mg / kg / day, about 40 mg / kg / day, about 50mg / kg / day, about 60 mg / kg / day, about 70 mg / kg / day, about 80 mg / kg / day, about 90 mg / kg / day, or about 100 mg / kg / day.

40. A method of treating colorectal cancer in a subject in need thereof comprising administering a therapeutically effective amount of a near-infrared conjugated monoamine oxidase A inhibitor (NMI) and a programmed cell death 1 (PD-1) inhibitor to the subject, thereby treating the colorectal cancer.

41. The method of claim 40, wherein the NMI isor an alternate salt, solvate, tautomer, or zwitterion thereof.

42. The method of claim 40, wherein the colorectal cancer comprises colorectal carcinoma, colorectal adenocarcinoma, colorectal melanoma, Dukes primary colorectal lymphoma, gastrointestinal stromal cancer, leiomyosarcoma, or colorectal carcinoid tumors.

43. The method of claim 42, wherein the colorectal cancer comprises colorectal carcinoma, colorectal adenocarcinoma, or metastatic colorectal cancer.

44. The method of claim 40, wherein the therapeutically effective amount is between about 1 and 250 mg / kg / day, between about 1 and 25 mg / kg / day, between about 5 and 25 mg / kg / day, between about 5 and 50 mg / kg / day, between about 10 and 50 mg / kg / day, between about 10 and 50 mg / kg / day, between about 10 and 100 mg / kg / day, between about 25 and 100 mg / kg / day, between about 25 and 250 mg / kg / day, or between about 50 and 250 mg / kg / day.

45. The method of claim 40, wherein the therapeutically effective amount is about 1 mg / kg / day, about 5 mg / kg / day, about 10 mg / kg / day, about 15 mg / kg / day, about 20 mg / kg / day, about 25mg / kg / day, about 30 mg / kg / day, about 40 mg / kg / day, about 50 mg / kg / day, about 60 mg / kg / day, about 70 mg / kg / day, about 80 mg / kg / day, about 90 mg / kg / day, or about 100 mg / kg / day.

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