A therapeutic agent for dedifferentiated prostate cancer containing an HDAC9 inhibitor as its active ingredient.

Abstract

The aim is to provide a treatment strategy for castration-resistant prostate cancer that does not respond to conventional HDAC inhibitors. [Solution] This application discloses, as one embodiment of the invention, a preventive and / or therapeutic agent for dedifferentiated prostate cancer containing an HDAC9 inhibitor as an active ingredient.

Description

[Technical Field]

[0001] The present invention relates to a therapeutic agent for dedifferentiated prostate cancer containing an HDAC9 inhibitor as an active ingredient, and is useful, for example, in the medical field. [Background technology]

[0002] Prostate cancer is the most common malignant tumor in men in Japan, with 87,756 cases per year (as of 2020). While endocrine therapy shows an extremely high response rate for metastatic prostate cancer, approximately 20% of patients develop resistance to endocrine therapy during the long course of treatment, resulting in castration-resistant prostate cancer. For such prostate cancers, treatment with novel AR pathway inhibitors and taxane-based anticancer drugs is indicated, but if resistance to these drugs also develops, there is no standard treatment. The function of histone deacetylases (HDACs) has attracted attention as a mechanism of treatment resistance in intractable malignant tumors, including prostate cancer, and inhibitors have been developed. In eukaryotic cells, DNA is folded while wrapped around histones and is stably housed in the nucleus in a structure called chromatin. The amino terminus (histone tail) of histones undergoes post-translational modifications such as acetylation, methylation, phosphorylation, and ubiquitination, and it is known that gene expression is regulated by changes in histone structure. Histone acetyltransferases (HATs) promote the translation of transcription factors by acetylating histone tails and opening up chromatin, while HDACs, conversely, decrease the translation of transcription factors by deacetylating histone tails. In humans, 18 HDAC families have been identified and are divided into four classes based on amino acid sequence homology and the structure of the enzyme domain. In particular, the HDAC family, belonging to Class I (HDAC1, 2, 3, 8) and Class II (HDAC4, 5, 6, 7, 8, 9, 10) with zinc-dependent domains, has been reported to promote cancer cell survival by activating the cell cycle through the aforementioned transcriptional repression effect, thereby reducing the expression of tumor suppressor factors such as p53 / p21 and cell cycle regulatory factors such as CDKs, and by reducing the expression of apoptosis-related genes such as BAX, BIM, and BCL. Accordingly, HDAC inhibitors with this inhibitory effect have been developed, and their efficacy against a wide range of cancer types, including prostate cancer, has been reported in patent documents (Patent Documents 1 and 2). In the case of prostate cancer, it has been shown that there was a correlation between the expression of HDAC1 or 2 and the proportion of high-risk prostate cancer in cases that had not received endocrine therapy or chemotherapy, and that the postoperative recurrence rate was also high in the group with high HDAC2 expression (Non-Patent Document 1). Furthermore, while Phase I and II clinical trials have been conducted for castration-resistant prostate cancer using Class I / II HDAC inhibitors Vorinostat, Belinostat, Panobinostat, and Chidamide, the rate of disease progression has been high in all cases, and currently, these drugs have not been approved for use in prostate cancer. Therefore, despite the pharmacological potential for the administration of HDAC inhibitors to castration-resistant prostate cancer, as described above, there has been a need in the medical field to clarify the reasons why conventionally used HDAC inhibitors do not always produce clinically effective results, and to develop new treatment strategies based on these findings. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] U.S. Patent No. 7399884 [Patent Document 2] Patent No. 6513078 [Non-patent literature]

[0004] [Non-Patent Document 1] Weichert,et al.Br.J.Cancer.2008 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The present inventors aim to provide a treatment strategy for castration-resistant prostate cancer in which conventional HDAC inhibitors are ineffective, in response to the above-mentioned demands in the medical field. [Means for solving the problem]

[0006] Based on the idea that the reason why the efficacy of HDAC inhibitors against castration-resistant prostate cancer has not been demonstrated in clinical trials may be due to inadequate patient stratification, the inventors proceeded to investigate the reason. As will be described in detail later, they found that among castration-resistant prostate cancers, there are those that exhibit the morphology of treatment-induced / related prostate cancer (tNEPC), which has dedifferentiated into neuroendocrine cancer (hereinafter, this cancer will also be referred to as "dedifferentiated prostate cancer"). Furthermore, they obtained new findings that HDAC9 is highly expressed in this "dedifferentiated prostate cancer," and that only HDAC inhibitors that have inhibitory activity against HDAC9 (hereinafter, also referred to as "HDAC9 inhibitors") are effective in suppressing cell proliferation. Based on these findings, the inventors completed the present invention, which aims to use HDAC9 inhibitors for the prevention and / or treatment of dedifferentiated prostate cancer. The present invention will be described below with reference to specific embodiments, but the present invention is not limited to these embodiments.

[0007] [1] A prophylactic and / or therapeutic agent for dedifferentiated prostate cancer, comprising an HDAC9 inhibitor as an active ingredient. [2] HDAC9 inhibitors are expressed by the following formula (I):

[0008] [ka]

[0009] (In the formula, R represents an optional aromatic ring group, and L represents a linker.) A compound represented by or a salt thereof, The preventive and / or therapeutic agents for dedifferentiated prostate cancer as described above [1]. [3] In equation (I), R has 1 to 3 C 1-6 A nitrogen-containing condensed heterocyclic group which may be substituted with an alkyl group, or 1 to 3 carbon atoms. 1-6 An aryl group which may be substituted with an alkyl group, L is an alkylene group whose constituent carbon atoms may be substituted with 1 to 3 groups selected from an amino group and a sulfonyl group, C 1-6 is an alkylene group, The preventive and / or therapeutic agent for dedifferentiated prostate cancer according to the above [2]. [4] The HDAC9 inhibitor is one or two compounds selected from panobinostat and belinostat (wherein each compound may be in the form of a salt), The preventive and / or therapeutic agent for dedifferentiated prostate cancer according to any one of the above [1] to [3]. [5] The dedifferentiated prostate cancer is a treatment-resistant cancer, The preventive and / or therapeutic agent for dedifferentiated prostate cancer according to any one of the above [1] to [4]. [6] The dedifferentiated prostate cancer is an initial cancer, The preventive and / or therapeutic agent for dedifferentiated prostate cancer according to any one of the above [1] to [4].

[0010] [7] A method for preventing and / or treating dedifferentiated prostate cancer, which comprises administering an effective amount of an HDAC9 inhibitor as an active ingredient to a subject in need of the administration. [8] An HDAC9 inhibitor for use in the prevention and / or treatment of dedifferentiated prostate cancer. [9] Use of an HDAC9 inhibitor for manufacturing a medicament for the prevention and / or treatment of dedifferentiated prostate cancer.

Effects of the Invention

[0011] According to the present invention, as one of its embodiments, a therapeutic agent for dedifferentiated prostate cancer containing an HDAC9 inhibitor as an active ingredient is disclosed, and a therapeutic strategy for "dedifferentiated prostate cancer", which is castration-resistant prostate cancer for which conventional types of HDAC inhibitors do not exhibit efficacy, is provided. [Brief Description of the Drawings]

[0012] [Figure 1]Figure 1 shows the concentration-dependent cell proliferation inhibitory effects of panobinostat and belinostat in a drug susceptibility test for histone deacetylase (HDAC) inhibitors using KBO100. [Figure 2] Figure 2 shows the gene expression patterns of the HDAC family in KBO100. [Modes for carrying out the invention]

[0013] The present invention is described in detail below, but unless otherwise specified, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which the invention pertains. Any methods and materials similar to or equivalent to those described herein may be used in the practice or testing of the present invention, but preferred methods and materials are described below. All publications and patents referred to herein are incorporated herein by reference for the purpose of describing and disclosing structures and methodologies described in publications that may be used in connection with the invention described herein. The present invention will be described in detail below based on embodiments, but the present invention is not limited to these. Those skilled in the art can modify embodiments of the present invention in various ways without departing from the meaning of the present invention, and such modifications are also included within the scope of the present invention.

[0014] Embodiments of the present invention include the following embodiments. "[A] A prophylactic and / or therapeutic agent for dedifferentiated prostate cancer containing an HDAC9 inhibitor as an active ingredient." (Embodiment A; hereinafter also referred to as "this therapeutic agent") The above embodiments will be described in detail below.

[0015] (Dedifferentiated prostate cancer) As detailed in the Examples section below, the inventors verified the characteristics of castration-resistant prostate cancer, which is ineffective against conventional HDAC inhibitors, using prostate cancer organoids established from cancer tissue of castration-resistant prostate cancer patients. Organoids are also called mini-organs, and their creation methods are widely known to those skilled in the art. Similar organoids to those established in this invention can be obtained by obtaining cancer tissue from patients with similar pathological conditions to those in the Examples section, applying the specific establishment method described in the Examples section, and selecting according to the selection criteria detailed in the Examples. As described below, immunohistochemical examination of the organoid revealed that both the primary tumor tissue and the organoid exhibited a loss of androgen receptor (AR) and prostate-specific antigen (PSA) expression, while showing elevated expression of the neuroendocrine markers synaptophysin and chromogranin A. This characteristic differs from typical adenocarcinoma and indicates a dedifferentiated prostate cancer (tNEPC: treatment-induced / related prostate cancer) that has evolved into a neuroendocrine carcinoma. Therefore, the organoid serves as a model for dedifferentiated prostate cancer. The construction of this model made it possible to select compounds effective for treating dedifferentiated prostate cancer by evaluating the antitumor effects of candidate compounds on this organoid. As detailed in the Examples section below, HDAC9 was specifically expressed in the organoid, while the expression of other HDAC family members was low. Furthermore, when the antitumor effects of 12 different HDAC inhibitors were examined against the organoid, only the inhibitors with inhibitory activity against HDAC9 showed antitumor effects. Therefore, it has become clear that by using HDAC9 expression as a biomarker to stratify castration-resistant prostate cancer patients and administering an inhibitor with HDAC9 inhibitory activity, it is possible to treat a portion of castration-resistant prostate cancer (dedifferentiated prostate cancer) that could not be treated with conventional HDAC inhibitors. Furthermore, the dedifferentiated prostate cancers targeted by this treatment include both cancers that have already received drug treatment (treatment-resistant dedifferentiated prostate cancer) and cancers that are receiving drug treatment for the first time (newly diagnosed dedifferentiated prostate cancer).

[0016] (HDAC9 inhibitor) (1) The term "HDAC9 inhibitor" in this therapeutic agent broadly encompasses compounds that have inhibitory activity against HDAC9, and its structure is not particularly limited. Furthermore, HDAC9 inhibitors may also have inhibitory activity against subtypes other than HDAC9. It is preferable to use a compound that exhibits high HDAC9 inhibitory activity and high selectivity for HDAC9. Since many compounds are already known as HDAC inhibitors, those skilled in the art can select one as appropriate. (2) The HDAC inhibitors concerned are not limited to the following, but for example, the following formula (I):

[0017] [ka]

[0018] (In the formula, R represents an optional aromatic ring group, and L represents a linker.) Examples include compounds represented by or salts thereof. Preferably, R has 1 to 3 C 1-6 A nitrogen-containing condensed heterocyclic group which may be substituted with an alkyl group, or 1 to 3 carbon atoms. 1-6 An aryl group which may be substituted with an alkyl group, L may have its constituent carbon atoms replaced by 1 to 3 groups selected from amino groups and sulfonyl groups, C 1-6 It is an alkylene group.

[0019] In this specification, "C 1-6Examples of the "alkyl group" include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, 1-ethylpropyl, hexyl, isohexyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 2-ethylbutyl and the like. In the present specification, "C 1-6 Examples of the alkylene group" include -CH2-, -(CH2)2-, -(CH2)3-, -(CH2)4-, -(CH2)5-, -(CH2)6-, -CH(CH3)-, -C(CH3)2-, -CH(C2H5)-, -CH(C3H7)-, -CH(CH(CH3)2)-, -(CH(CH3))2-, -CH2-CH(CH3)-, -CH(CH3)-CH2-, -CH2-CH2-C(CH3)2-, -C(CH3)2-CH2-CH2-, -CH2-CH2-CH2-C(CH3)2-, -C(CH3)2-CH2-CH2-CH2 and the like. In the present specification, examples of the "aromatic ring group" include an "aryl group" and an "aromatic heterocyclic group". In the present specification, the "aryl group" is preferably a "C 6-14 aryl group", and examples thereof include phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl and the like. More preferred is a C 6-14 aryl group, still more preferred is a C 6-10 aryl group. In the present specification, examples of the "aromatic heterocyclic group" include 5- to 14-membered (preferably 5- to 10-membered) aromatic heterocyclic groups containing 1 to 4 heteroatoms selected from nitrogen atoms, sulfur atoms and oxygen atoms in addition to carbon atoms as ring-constituting atoms. Suitable examples of the "aromatic heterocyclic group" include thienyl, furyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, oxazolyl, isoxazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridadinyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,4-thiadiazolyl, 1,3,4-thiadiazolyl, triazolyl, tetrazolyl, triazinyl, and other 5- to 6-membered monocyclic aromatic heterocyclic groups; Benzothiophenyl, benzofuranil, benzimidazolyl, benzoxazolyl, benzoisoxazolyl, benzothiazolyl, benzoisothiazolyl, benzotriazolyl, imidazopyridinyl, thienopyridinyl, phlopyridinyl, pyrrolopyridinyl, pyrazolopyridinyl, oxazolopyridinyl, thiazolopyridinyl, imidazopyridinyl, imidazopyridinyl, thienopyridinyl, phlopyridinyl, pyrrolopyridinyl, pyrazolopyridinyl, oxazolopyridinyl, thiazolopyridinyl Examples of condensed aromatic heterocyclic groups include pyrazolotriazinyl, naphtho[2,3-b]thienyl, phenoxathiinyl, indolyl, isoindolyl, 1H-indazolyl, prinyl, isoquinolyl, quinolyl, phthalazinyl, naphthylidinyl, quinoxalinyl, quinazolinyl, sinnolinyl, carbazolyl, β-carbolinyl, phenanthidinyl, acridinyl, phenazinyl, phenothiazinyl, and phenoxazinyl, and more specifically, 8 to 14-membered condensed polycyclic (preferably 2 or 3-cyclic) aromatic heterocyclic groups. Preferably, an 8- to 14-membered condensed bicyclic aromatic heterocyclic group is used, and more preferably, a nitrogen atom is included as an inner ring component. In this specification, "substituent" refers to a halogen atom, a nitro group, a cyano group, an oxo group, a hydroxyl group, and C 1-6 Alkyl groups are examples. In this specification, "halogen atoms" include, for example, fluorine, chlorine, bromine, and iodine. In this specification, the "linker" is not particularly limited as long as it can link R and the benzene ring, but its constituent carbon atoms may be replaced by, for example, 1 to 3 groups selected from amino groups and sulfonyl groups. 1-6 An example is the alkylene group.

[0020] (3) More preferred HDAC9 inhibitors include panobinostat (also spelled Panobinostat) (structural formula on the left below) and belinostat (also spelled Belinostat) (structural formula on the right below). Both inhibitors are approved and commercially available drugs.

[0021] [ka]

[0022] In the embodiments described above, the "HDAC9 inhibitor" can be used in either its free form or in the form of a salt thereof (preferably a pharmaceutically acceptable salt thereof). Those skilled in the art can appropriately select from both forms to carry out the present invention, taking into account the characteristics of the individual HDAC9 inhibitor used. Examples of salts that are acceptable as pharmaceuticals include salts with inorganic acids such as hydrochloride, hydrobromide, sulfate, and phosphate; salts with acids such as lactate, acetate, fumarate, oxalate, citrate, methanesulfonate, benzenesulfonate, tosylate, and maleate; and salts with bases such as alkali metal salts such as sodium salt and potassium salt, and alkaline earth metal salts such as calcium salt; and salts with amino acids such as glycine salt, lysine salt, arginine salt, ornithine salt, glutamate, and aspartate.

[0023] If an HDAC9 inhibitor has isomers such as optical isomers, stereoisomers, positional isomers, or rotational isomers, it can be used as one of the isomers or as a mixture thereof. If an HDAC9 inhibitor has optical isomers, it is preferable to use the optical isomers separated from the racemate. These isomers can be obtained as individual optical isomers by known synthesis methods, separation methods (e.g., concentration, solvent extraction, column chromatography, recrystallization, etc.), optical resolution methods (e.g., fractional recrystallization, chiral column chromatography, diastereomerization, etc.). HDAC9 inhibitors may be in crystalline form, and may be a single crystalline form or a mixture of crystalline forms. Crystals can be produced by crystallization using known crystallization methods. The HDAC9 inhibitor may be a solvate (e.g., hydrate) or a solvate (e.g., nonhydrate), and either can be used in the embodiment described above.

[0024] HDAC9 inhibitors can also be used in the form of prodrugs. Those skilled in the art can design such prodrugs as appropriate, and such prodrugs can be manufactured by methods known to the art. Such prodrugs may be converted to the target HDAC9 inhibitor under physiological conditions, as described on pages 163 to 198 of "Molecular Design," Volume 7, "Pharmaceutical Development," published by Hirokawa Shoten in 1990.

[0025] "Prevention" includes preventing the onset (or recurrence) of a disease (the entire condition or symptoms, or one or more conditions or symptoms) and delaying the onset (or recurrence) of the disease. "Prophylactic effective dose" means a dose of HDAC9 inhibitor sufficient to achieve this objective.

[0026] "Treatment" includes the cure of a disease (the entire condition or symptoms, or one or more conditions or symptoms), improvement of the disease, and suppression of the progression of the disease's severity. "Therapeutic dose" means a dose of HDAC9 inhibitor sufficient to achieve these objectives.

[0027] (Regarding the target recipients of the treatment) In the embodiments described above, an HDAC9 inhibitor is appropriately selected and used from the viewpoint of efficacy, safety, etc. Therefore, HDAC9 inhibitors can be safely administered to mammals (e.g., humans, monkeys, dogs, horses, etc.) (especially to humans).

[0028] (Regarding the route of administration) HDAC9 inhibitors may be administered orally or parenterally (e.g., intravenously, by infusion, intramuscularly, subcutaneously, intra-organally, intranasally, intradermally, transdermally, ophthalmally, intracerebrally, intrarectally, intravaginally, intraperitoneally, and to the lesion) either alone or as part of a pharmaceutical composition.

[0029] (Regarding dosage) The dosage of HDAC9 inhibitors varies depending on the patient, route of administration, and age and symptoms, but is not particularly limited. For example, the dosage of the active ingredient, the HDAC9 inhibitor, is 0.1 to 2500 mg, preferably 1 to 2000 mg, per oral dose. This dosage can be administered in 1 to 3 divided doses per day. Those skilled in the art can appropriately select and use the dosage according to the characteristics of the HDAC9 inhibitor used. Furthermore, when administered in the form of a sustained-release formulation, it is also possible to administer it every other day or at longer intervals to correspond to the dosage.

[0030] (Regarding the form of administration) HDAC9 inhibitors can be used either alone or in the form of a pharmaceutical composition containing the HDAC9 inhibitor as an active ingredient together with a pharmaceutically acceptable carrier. In this specification, both forms will be collectively referred to as "medicine."

[0031] Examples of such pharmaceutical compositions include tablets (including sugar-coated tablets, film-coated tablets, sublingual tablets, orally disintegrating tablets, buccal tablets, etc.), pills, powders, granules, capsules (including soft capsules and microcapsules), lozenges, syrups, liquids, emulsions, suspensions, controlled-release formulations (e.g., immediate-release formulations, sustained-release formulations, sustained-release microcapsules), aerosols, films (e.g., orally disintegrating films, oral mucosal adhesive films), injections (e.g., subcutaneous injections, intravenous injections (e.g., boluses), intramuscular injections, intraperitoneal injections), drip infusions, transdermal formulations, ointments, lotions, patches, suppositories (e.g., anal suppositories, vaginal suppositories), pellets, nasal formulations, pulmonary formulations (inhalants), eye drops, and the like.

[0032] As "pharmaceutical carriers," various carriers commonly used in the field of pharmaceutical technology can be used. Specific examples of "pharmaceutical carriers" include, for example, in solid dosage forms, excipients (e.g., lactose, sucrose, D-mannitol, starch, corn starch, crystalline cellulose, light anhydrous silicic acid, etc.), lubricants (e.g., magnesium stearate, talc, colloidal silica, etc.), binders (e.g., crystalline cellulose, sucrose, D-mannitol, dextrin, hydroxypropylcellulose, hydroxypropylmethylcellulose, polyvinylpyrrolidone, starch, sucrose, gelatin, methylcellulose, sodium carboxymethylcellulose, etc.) and disintegrants (e.g., starch, carboxymethylcellulose, calcium carboxymethylcellulose, sodium carboxymethyl starch, L-hydroxypropylcellulose, etc.).

[0033] In liquid formulations, solvents (e.g., sterile water for injection, isotonic saline, alcohol, propylene glycol, macrogol, sesame oil, etc.), solubilizers (e.g., polyethylene glycol, propylene glycol, D-mannitol, benzyl benzoate, ethanol, triethanolamine, sodium carbonate, sodium citrate, etc.), suspending agents (e.g., surfactants such as stearyltriethanolamine, sodium lauryl sulfate, laurylaminopropionic acid, lecithin, benzalkonium chloride, glyceryl monostearate; hydrophilic polymers such as polyvinyl alcohol, polyvinylpyrrolidone, sodium carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, hydroxypropylcellulose, etc.), isotonic agents (e.g., glucose, D-sorbitol, sodium chloride, glycerin, D-mannitol, etc.), buffers (e.g., buffers such as phosphates and citrates), and analgesics (e.g., benzyl alcohol, etc.) can be used.

[0034] If necessary, further formulation additives such as preservatives (e.g., parahydroxybenzoic acid esters, chlorobutanol, benzyl alcohol, sorbic acid, etc.), antioxidants (e.g., sulfites, ascorbic acid, α-tocopherol, etc.), colorants, and sweeteners may be added.

[0035] The pharmaceutical composition may vary depending on the dosage form, administration method, carrier, etc., but it can be manufactured by adding an HDAC9 inhibitor at a rate of typically 0.01 to 99% (w / w), preferably 0.1 to 85% (w / w), relative to the total amount of the formulation. The pharmaceutical composition can be manufactured by methods conventional in the field of pharmaceutical technology, depending on its form. The pharmaceutical composition may be formed into a controlled-release formulation such as a rapid-release formulation or a sustained-release formulation containing the active ingredient.

[0036] (Regarding concomitant use with other medications) In implementing the above embodiments, HDAC9 inhibitors can be used in combination with other drugs to prevent or treat the target disease, and excellent preventive and / or therapeutic effects can be expected through combination therapy with other drugs. Furthermore, such combination therapy can be expected to reduce the dosage of other drugs and thereby reduce their side effects. Drugs that can be used in combination with such HDAC9 inhibitors (hereinafter sometimes abbreviated as "combination drugs") can be appropriately selected in consideration of the type of disease the patient has, the severity of its symptoms, etc. For example, combination therapy with docetaxel, cabazitaxel, cisplatin, carboplatin, etoposide, and irinotecan can be considered. The administration method of the concomitant drug is not particularly limited, and the HDAC9 inhibitor and the concomitant drug may be combined at the time of administration. For example, it can be used in the following forms: (1) administration of a formulation containing the HDAC9 inhibitor and the concomitant drug in combination; (2) simultaneous or separate administration of two formulations obtained by separately formulating the HDAC9 inhibitor and the concomitant drug via the same route of administration; or (3) simultaneous or separate administration of two formulations obtained by separately formulating the HDAC9 inhibitor and the concomitant drug via different routes of administration. The preferred form can be appropriately selected according to the actual situation in the medical field. A preparation containing the above-mentioned HDAC9 inhibitor in combination with a concomitant drug can be manufactured by a person skilled in the art in accordance with the pharmaceutical composition containing the HDAC9 inhibitor described above. The dosage of concomitant medications may be appropriately selected based on clinically used doses. Furthermore, the mixing ratio of HDAC9 inhibitors to concomitant medications may be appropriately selected depending on the target disease or symptoms, route of administration, and type of concomitant medication used. Generally, this can be determined appropriately based on the general clinical dose of the concomitant medication used, in accordance with the actual conditions of the medical setting.

[0037] The embodiments of the present invention also include the following embodiments. "[B] A method for the prevention and / or treatment of dedifferentiated prostate cancer, comprising administering an effective dose of an HDAC9 inhibitor as an active ingredient to a subject requiring administration." (Embodiment B; This treatment method) "[C] HDAC9 inhibitors used for the prevention and / or treatment of dedifferentiated prostate cancer." (Embodiment C; this inhibitor) "[D] Use of HDAC9 inhibitors for the manufacture of drugs for the prevention and / or treatment of dedifferentiated prostate cancer." (Implementation D; Use)

[0038] For details regarding the technical aspects that define the above embodiments, such as "HDAC9 inhibitor," "dedifferentiated prostate cancer," "target patient," "dosage," "route of administration," and "form of administration," refer to the corresponding descriptions of the technical aspects in Embodiment A. [Examples]

[0039] The present invention will be described in detail below based on examples, but the present invention is not limited thereto. Those skilled in the art can modify embodiments of the present invention in various ways without departing from the meaning of the present invention, and such modifications are also included within the scope of the present invention.

[0040] 1. Experimental Method (1) Culturing organoids The prostate cancer cells used in this invention are cancer organoids established from tissue derived from prostate cancer patients. A portion of a sample obtained from castration-resistant prostates that underwent transurethral surgery or biopsy at the Department of Urology, Keio University Hospital, was finely sectioned and unicellularized by stirring in a 5 mg / ml collagenase type II (Sigma-Aldrich) and 100 μg / ml DNase I (AppliChem) solution at 37°C for 30 minutes. These cells were seeded on Growth Factor Reduced Matrigel (Corning) and cultured in AdMEM / F12 medium containing 100 ng / ml Wnt3a, 1 μM / ml R-spondin, 1 mM GlutaMAX, 1 × B27, 2 mM N-acetylcysteine, 100 ng / ml IGF1, 50 ng / ml FGF2, 50 ng / ml EGF, 500 nM A83-01, and 10 μM Y-27632 to create organoids.

[0041] (2) Background of patients with organoid-derived organoids The organoid strain KBO100 was established from 10 lines of organoids developed from 10 patients who underwent endocrine therapy but developed enlarged primary tumors, multiple lymph node, bone, and lung metastases, and became castration-resistant. Specifically, it was developed using a specimen resected from a primary prostate cancer tumor in a 71-year-old Japanese male.

[0042] (3) About KBO100 Immunohistochemical examination revealed that KBO100 exhibited characteristics of a dedifferentiated prostate cancer (tNEPC: treatment-induced / related prostate cancer), with the primary tumor's pathological tissue and organoids showing a loss of androgen receptor (AR) and prostate-specific antigen (PSA) expression, while the expression of neuroendocrine markers synaptophysin and chromogranin A was elevated. As mentioned above, clinical trials of class I / II HDAC inhibitors such as Vorinostat for castration-resistant prostate cancer did not confirm sufficient efficacy against prostate cancer. However, the inventors focused on the possibility that the efficacy of HDAC inhibitors could not be accurately confirmed in past clinical trials because PSA response was used as the endpoint. Of the 10 organoid lines established, KBO100, as described above, showed the most typical morphology of dedifferentiated prostate cancer, with abolition of androgen receptor (AR) and prostate-specific antigen (PSA) expression and increased expression of neuroendocrine markers synaptophysin and chromogranin A, and also exhibited the highest proliferative capacity and malignancy. Based on these characteristics, it became clear that KBO100 can serve as an optimal model for dedifferentiated prostate cancer targeted by the present invention and is suitable as an evaluation system for the efficacy of candidate compounds against dedifferentiated prostate cancer. Therefore, the inventors decided to use KBO100 for evaluating the efficacy of the compound in developing a treatment strategy for castration-resistant prostate cancer (i.e., dedifferentiated prostate cancer) in which conventional HDAC inhibitors are ineffective.

[0043] (4) Assessment of drug susceptibility Using KBO100, drug susceptibility testing was performed for 12 types of histone deacetylase (HDAC) inhibitors. Specifically, single-cell KBO100 was seeded in a 384-well plate at a rate of 3000 cells per well, and 40 μl of medium was administered to promote organoid formation. On Day 3, the 12 drugs (Panobinostat, Vorinostat, Belinostat, Entinostat, Citarinostat, Abexinostat, Givnostat, Tucidinostat, Quisinostat, Mocelinostat, Resminostat, Ricolinostat) were administered at final concentrations of 0.5 nM, 5 nM, and 50 nM, respectively. On Day 9, CellTiter-Glo TM We quantified cell viability using the principle of a 3D-based ATP assay and evaluated the antitumor effect of the drug.

[0044] (5) Single-cell RNA analysis of organoids Single-cell RNA analysis was performed on prostate cancer organoids, including KBO100. Each organoid was trypsin-treated to prepare a single-cell suspension. After cell lysis, the cells were barcoded using the Chromium Single Cell 3' Library Kit v2 (x10 Genomics). Processing was performed according to the protocol. cDNA was synthesized by reverse transcription and amplified by PCR. After adjusting the library concentration, sequencing was performed using an Illumina NovaSeq 6000 with 150 bp paired-end leads. Read mapping was performed using Cell Ranger (x10 Genomics), and the obtained data was normalized based on SCTransform. For subsequent data analysis, Seurat was used to search for gene expression characteristic of KBO100.

[0045] 2. Experimental Results (1) Results of drug susceptibility testing The drug challenge test revealed that only two HDAC inhibitors, Panobinostat and Belinostat, exhibited concentration-dependent cell proliferation inhibitory effects (IC50 of 4.06 nM and 4.50 nM, respectively). The results are shown in Figure 1. The inhibitory activity (IC50) against each HDAC family was as follows: for the former, HDAC1: 3 nM, HDAC2: 3 nM, HDAC3: 4 nM, HDAC6: 3 nM, HDAC8: 248 nM, HDAC4: 23 nM, HDAC7: 18 nM, HDAC9: 6 nM; and for the latter, HDAC1: 41 nM, HDAC2: 125 nM, HDAC3: 30 nM, HDAC6: 3 nM, HDAC8: 140 nM, HDAC4: 115 nM, HDAC7: 137 nM, HDAC9: 70 nM. Only these two drugs exhibited inhibitory activity against HDAC9.

[0046] (2) Expression of the HDAC family in organoids Single-cell RNA analysis revealed differences in HDAC family gene expression patterns in prostate cancer organoids. Specifically, HDAC9 expression was specific in KBO100, where Panobinostat and Belinostat showed efficacy, while the expression of other HDAC family members was extremely low. These results are shown in Figure 2. From this, it was concluded that Panobinostat and Belinostat exerted their cell proliferation inhibitory effects through HDAC9 inhibition. While a correlation between HDAC1 and HDAC2 expression and the presence of high-risk prostate cancer has been reported in prostate cancer (Weichert, et al. Br.J.Cancer.2008), the significance of HDAC9 has not been investigated until now. Clinical trials of HDAC inhibitors (Vorinostat, Belinostat, Panobinostat, Chidamide) for castration-resistant prostate cancer have been conducted, and the results have been reported to show no efficacy. However, the organoids in this invention that showed efficacy with HDAC inhibitors were dedifferentiated cancers that had lost the characteristics of conventional adenocarcinomas and acquired the morphology of neuroendocrine cancers, and their morphology was completely different. The efficacy of an inhibitor based on HDAC9 inhibition was demonstrated against such dedifferentiated prostate cancers. [Industrial applicability]

[0047] The present invention relates to a therapeutic agent for dedifferentiated prostate cancer containing an HDAC9 inhibitor as an active ingredient, and is useful, for example, in the medical field.

Claims

1. A preventive and / or therapeutic agent for dedifferentiated prostate cancer, containing an HDAC9 inhibitor as an active ingredient.

2. HDAC9 inhibitors are expressed by the following formula (I): 【Chemistry 1】 (In the formula, R represents an optional aromatic ring group, and L represents a linker.) A compound represented by or a salt thereof, The preventive and / or therapeutic agent for dedifferentiated prostate cancer according to claim 1.

3. In equation (I), R has 1 to 3 C １－６ A nitrogen-containing condensed heterocyclic group which may be substituted with an alkyl group, or 1 to 3 carbon atoms. １－６ An aryl group which may be substituted with an alkyl group, L may have its constituent carbon atoms replaced by 1 to 3 groups selected from amino groups and sulfonyl groups, C １－６ It is an alkylene group. The preventive and / or therapeutic agent for dedifferentiated prostate cancer according to claim 2.

4. The HDAC9 inhibitor is one or two compounds selected from panobinostat and belinostat (where each compound may be in the form of a salt). The preventive and / or therapeutic agent for dedifferentiated prostate cancer according to claim 1.

5. Dedifferentiated prostate cancer is a type of cancer that is resistant to treatment. A preventive and / or therapeutic agent for dedifferentiated prostate cancer according to any one of claims 1 to 4.

6. Dedifferentiated prostate cancer is the initial type of cancer. A preventive and / or therapeutic agent for dedifferentiated prostate cancer according to any one of claims 1 to 4.

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