Drug sensitive marker for response to CDK4 / 6 inhibitor and application

Abstract

The invention provides a drug sensitive marker for CDK4 / 6 inhibitor response and application, a candidate gene, namely a marker BAP1, is screened out by adopting CRISPR high-throughput screening and multiple experimental methods, and in-vivo and in-vitro experiments prove that the diagnosis and treatment marker BAP1 can respond to the curative effect of a CDK4 / 6 inhibitor in cancers, such as primary liver cancer, gastric cancer, breast cancer, cancer, cancer and the like. The marker provided by the invention has accurate and rapid guiding significance for treatment of cancers with the above characteristics, and has great application and popularization prospects.

Description

Technical Field

[0001] The present invention belongs to the field of biomedicine, and in particular relates to drug sensitivity markers for responding to CDK4 / 6 inhibitors and applications. Background Art

[0002] CDK4 / 6 inhibitors are a class of anti-tumor drugs that target cell cycle regulation. They inhibit cyclin-dependent kinases 4 and 6 (CDK4 / 6) and prevent Rb protein phosphorylation, thereby inducing G1 phase cell cycle arrest and inhibiting tumor cell proliferation. Currently, FDA-approved CDK4 / 6 inhibitors include Palbociclib, Ribociclib, and Abemaciclib, which have been widely used in the treatment of hormone receptor-positive, HER2-negative breast cancer, and have shown potential efficacy in a variety of other solid tumors (such as liver cancer and melanoma). In addition, CDK4 / 6 inhibitors can be used in combination with immunotherapy, targeted therapy, etc. to enhance anti-tumor effects and overcome drug resistance by regulating the tumor microenvironment and affecting immune responses. Therefore, the art needs to treat patients with BAP1 mutations and needs biomarkers that will be used to determine when CDK4 / 6 inhibitors should be used to treat cancer.

[0003] Loss of cell cycle control is an important hallmark of cancer, and many studies have reported changes in genes that regulate the cell cycle in liver cancer cells. Using a variety of sequencing methods and experimental means, researchers have systematically studied the genomic characteristics of liver cancer, proposed molecular typing criteria for liver cancer, and discovered new diagnostic and prognostic markers. These results provide key information for the clinical diagnosis, prognosis, and treatment of liver cancer. Among them, researchers found that changes in the CCND1-CDK4 / 6-Rb pathway often occur in HCC patients: high expression of CDK4 was found in more than 70% of patients; and inactivation of the gene CDKN2A encoding the cell cycle inhibitor p16INK4a was found in more than 50% of patients; in addition, approximately 20% of patients will have inactivation of the tumor suppressor gene Rb. Therefore, targeting the cell cycle is expected to establish a potential HCC treatment strategy.

[0004] Take primary liver cancer as an example, which is translated into English as Primary liver cancer, abbreviated as PLC. It is mainly divided into three subtypes: the first subtype is hepatocellular carcinoma, Hepatocellular carcinoma, HCC, the second subtype is intrahepatic cholangiocarcinoma, Intrahepatic cholangiocarcinoma, ICC, and the third subtype is combined hepatocellular and cholangiocarcinoma, cHCC-ICC. Among them, hepatocellular carcinoma, Hepatocellular carcinoma, HCC is the most important histological type of primary liver cancer, accounting for 80%-85% of primary liver cancer. Hepatocellular carcinoma, HCC is a very aggressive disease. As of 2020, nearly 906,000 people worldwide have been diagnosed with liver cancer, which is the third leading cause of cancer-related mortality worldwide. Among them, there are about 410,000 new cases of liver cancer in my country, accounting for about 50% of the new cases of liver cancer in the world, and the 5-year survival rate of such patients is only about 18%. Although the treatment of HCC has improved greatly in the past decade, most patients diagnosed with advanced HCC are unable to undergo radical ablative treatments such as liver resection, liver transplantation, or local ablation. What is more serious is that the prognosis of patients with advanced HCC is very poor. In the treatment of patients with advanced HCC, the multikinase inhibitor sorafenib has been the only available treatment option for more than a decade. Recently, other small molecule drugs such as lenvatinib have been approved for first-line HCC treatment, while second-line treatment options include regorafenib and cabozantinib. However, even for HCC patients who have used the aforementioned drugs, their expected survival does not exceed 2 years. Therefore, it is urgent to explore more effective targeted treatment strategies.

[0005] Studies have shown that CDK4 / 6 inhibitors greatly improve disease control in patients with HR-positive breast cancer, but not all patients are responsive to them, and in most cancer patients, long-term use of CDK4 / 6 inhibitors can lead to the emergence of acquired resistance. When CDK4 / 6 inhibitors are used as first-line treatment drugs, the median time for breast cancer patients to develop treatment resistance is 24 months, while it is only 12 months when used as a second-line treatment strategy. Previous studies have shown that different tumors have different resistance mechanisms to CDK4 / 6 inhibitors, including intrinsic resistance and acquired resistance. The intrinsic resistance mechanism is mainly manifested in abnormal expression of cell cycle-related proteins, such as loss of RB, activation of E2F, amplification of CDK4 / 6, activation of CDK2, amplification of CDKN2A (P16), etc. In addition, the activation of some pathways upstream of the cell cycle, including the PI3K / AKT / mTOR pathway and the FGFR pathway, acts as a bypass pathway for cell cycle progression, which can reduce the efficacy of CDK4 / 6 inhibitors and lead to acquired resistance to CDK4 / 6 inhibitors. Therefore, exploring the tumor-specific resistance mechanism of CDK4 / 6 inhibitors and finding targets for combination therapy are important issues in overcoming resistance to targeted therapy and promoting precision cancer treatment.

[0006] For patients who are resistant to CDK4 / 6 inhibitors, new combination therapy strategies are urgently needed to delay progression or improve survival. Combination therapy is a widely used option in cancer treatment that reduces the risk of drug resistance and tumor recurrence that are common in monotherapy regimens. More and more studies have shown that combination therapy provides new treatment options for treating tumors. Although monotherapy remains a common treatment for many different types of cancer, combination therapy is generally more effective than monotherapy. Compared with monotherapy, combination therapy is less toxic because it targets different signaling pathways and works in a synergistic manner, which greatly reduces the therapeutic dose of each drug. In addition, monotherapy treatment is prone to induce drug resistance because long-term continuous treatment with a single drug induces cancer cells to upregulate alternative salvage pathways. For example, breast cancer cells upregulate PI3K, mTOR and other pathways when treated with CDK4 / 6 inhibitors. These are signal compensation pathways for cell cycle progression, leading to resistance to CDK4 / 6 inhibitors. Combination therapy can produce more effective therapeutic effects in a short period of time, greatly reducing the incidence of drug resistance. The combined use of drugs from different pathways can synergistically and significantly increase the anti-cancer effect. Therefore, this drug combination strategy has been widely used in clinical practice.

[0007] In summary, at present, this field still faces the following problems in the application of CDK4 / 6 inhibitors:

[0008] ①Poor treatment effect: Traditional treatment methods such as surgery, chemotherapy and radiotherapy have limited effects, are prone to recurrence and are difficult to control in the late stage.

[0009] ② Limitations of CDK4 / 6 inhibitor monotherapy: The clinical efficacy of single CDK4 / 6 inhibitors in the treatment of liver cancer is limited, and more effective combination drug strategies need to be developed.

[0010] ③ The target of combined drug use is unclear: The potential targets that have synergistic effects with CDK4 / 6 inhibitors in the treatment of liver cancer have not yet been fully revealed, which restricts the formulation of combined treatment strategies.

[0011] ④ The problem of drug resistance is prominent: Liver cancer is prone to develop drug resistance, which leads to treatment failure and disease deterioration. It is necessary to explore the mechanism of drug resistance and intervention methods.

[0012] This field is in urgent need of an effective means to solve a series of problems at this stage. Summary of the invention

[0013] In view of the shortcomings of the prior art, the present invention provides drug sensitivity markers for responding to CDK4 / 6 inhibitors and applications.

[0014] To achieve the above object, the present invention adopts the following technical solutions:

[0015] Use of a CDK4 / 6 inhibitor in the manufacture of a drug for treating cancers marked by BAP1, wherein the cancer is selected from liver cancer, gastric cancer, endometrial cancer, HER2-negative breast cancer, and melanoma;

[0016] The CDK4 / 6 inhibitor is selected from agents or compounds capable of inhibiting the transcription, expression, or function of the BAP1 gene; or inhibitors capable of targeting BAP1 or antibodies / immunologically active fragments capable of binding to BAP1 protein products, or pharmaceutically acceptable carriers;

[0017] The CDK4 / 6 inhibitor is selected from palbociclib, ribociclib, abemaciclib, pembrolizumab, letrozole, apatinib, everolimus and fulvestrant.

[0018] Preferably, the CDK4 / 6 inhibitor is selected from apatinib, palbociclib, and abemaciclib.

[0019] Preferably, the drug sensitivity marker is RNA or its reverse transcribed cDNA, or protein.

[0020] Preferably, the drug sensitivity marker is BAP1.

[0021] Furthermore, the drug sensitivity marker BAP1 was screened by CRISPR knockout based on the CRISPR whole genome library.

[0022] Preferably, the carrier comprises one or more of lactose, dextrose, sucrose, sorbitol, mannitol, starch, gum arabic, calcium phosphate, alginate, gelatin, calcium silicate, microcrystalline cellulose, polyvinyl pyrrolidone, cellulose, water, syrup, methylcellulose, methyl hydroxybenzoate, propyl hydroxybenzoate, talc, magnesium stearate and mineral oil.

[0023] Preferably, the pharmaceutical composition comprises at least one of a lubricant, a wetting agent, a sweetener, a flavoring agent, an emulsifier, a suspending agent, and a preservative.

[0024] Furthermore, the pharmaceutical composition can be administered orally or parenterally. When administered parenterally, it can be administered by intravenous injection, intranasal injection, local injection, intraventricular injection, spinal cavity injection, subcutaneous injection, intraperitoneal injection, transdermal administration, etc.

[0025] Furthermore, the appropriate dosage of the pharmaceutical composition can be prescribed in a variety of ways depending on factors such as the formulation method, administration method, patient's age, weight, gender, morbidity, food, administration time, administration route, excretion rate and reaction sensitivity. Generally, a skilled physician can easily determine and prescribe an effective dosage for the desired treatment or prevention.

[0026] Furthermore, the pharmaceutical composition is formulated using pharmaceutically acceptable carriers and / or excipients according to a method that can be easily implemented by a person of ordinary skill in the art to which the present invention belongs, so that it can be prepared in a unit dosage form or prepared in a multi-volume container. In this case, the dosage form is a solution, suspension or emulsion in an oily or aqueous medium, or can also be in the form of an extract, powder, granule, tablet or capsule, and can also include a dispersant or stabilizer.

[0027] In order to solve the above technical problems, the present invention also provides the use of CDK4 / 6 inhibitors in the manufacture of reagents for drug sensitivity marker detection.

[0028] Preferably, the drug sensitivity test includes drug resistance test and drug sensitivity test.

[0029] Preferably, the reagents for drug sensitivity marker detection are tested by methods including: RT-PCR, fluorescent quantitative PCR, mRNA Sequencing, mRNA array detection technology, immunohistochemistry, immunofluorescence, Western blot, ELISA, flow cytometry, immunological detection, and chemical detection.

[0030] In addition, the CDK4 / 6 inhibitor of the present invention can be applied to the analysis system of cancer of BAP1 marker, and the operation steps of the analysis system include:

[0031] Target expression detection: used to detect the expression of multiple CDK4 / 6 inhibitor combined drug sensitivity markers in samples;

[0032] Obtaining samples: The samples can be selected from liver cancer, gastric cancer, endometrial cancer, HER2-negative breast cancer, or melanoma tissues, which are samples of cancer types that use the BAP1 marker as a biomarker;

[0033] Drug sensitivity analysis: Determine the drug effect based on the expression level of the drug sensitivity marker of the same type of CDK4 / 6 inhibitor combination drug used in the target expression detection step;

[0034] Result output: used to output the results obtained by the drug sensitivity analysis device, which are divided into resistance analysis results and sensitivity analysis results.

[0035] The above-mentioned technical scheme provided by the present invention involves the use of CDK4 / 6 inhibitors in the manufacture of drugs for treating cancers with BAP1 markers, and also involves the use of CDK4 / 6 inhibitors in the manufacture of reagents for detecting drug sensitivity markers. It also discloses an applicable analysis system for cancers with BAP1 markers, and examines the role of CDK4 / 6 inhibitors in the preparation of drugs for treating cancer in multiple aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Flow chart for screening CDK4 / 6 inhibitor targets in CRISPR libraries;

[0037] Figure 2 Schematic diagram for CRISPR target screening and validation;

[0038] Figure 3 In in vitro experiments, the combination of CDK4 / 6 inhibitor abemaciclib and BAP1 inhibitor BAP1-IN-1 can synergistically inhibit the growth of tumor cells. A. Schematic diagram of Western blot detection of the knockdown efficiency of shBAP1 and sgBAP1;

[0039] Figure 4 Schematic diagram of the synergistic effect of CDK4 / 6 inhibitor and BAP1 leading to cell cycle arrest;

[0040] Figure 5 Schematic diagram of in vivo experiments showing that simultaneous inhibition of BAP1 and CDK4 / 6 can effectively inhibit the growth of tumor cells;

[0041] Figure 6Validate the sensitization effect of CDK4 / 6 inhibitors on BAP1-deficient HCC patient-derived organoids;

[0042] Figure 7 Schematic diagram of how the combination of BAP1 and CDK4 improves survival. DETAILED DESCRIPTION

[0043] The present invention is further described below by means of specific examples, but the scope of the present invention is not limited thereto.

[0044] In the specification and claims of the application, unless otherwise stated, the scientific and technological terms used herein have the meanings commonly understood by those skilled in the art. However, in order to better understand the present invention, the definition and explanation of some related terms are provided below. In addition, when the definition and explanation of the terms provided in the application are inconsistent with the meanings commonly understood by those skilled in the art, the definition and explanation of the terms provided in the application shall prevail.

[0045] Embodiment 1:

[0046] Whole genome library screening for synergistic targets of CDK4 / 6 inhibitors in primary liver cancer. In this example, the SNU739 cell line was used for whole genome CRISPR-Cas9 library screening. The study aims to find potential targets for synergy with CDK4 / 6 inhibitors. The DNA of surviving cells on Day 0 and Day 21 after 21 days of treatment with 300nM CDK4 / 6 inhibitor Abemaciclib was extracted, and the differences in sgRNAs at these two time points were compared to find potential synergistic targets for CDK4 / 6 inhibitors. In short, we found that compared with the cells in the Day 0 group, the sgRNA missing in the D21 group cells may be a potential synergistic target for CDK4 / 6 inhibitors. By comparing the differences in sgRNAs in the DNA of the DMSO group and the Abemaciclib group, the sgRNAs that were specifically missing in the Abemaciclib group were found. Specifically, it refers to the sgRNAs lost in the surviving cells after treatment with the CDK4 / 6 inhibitor, refer to Figure 1 A, we sorted sgRNAs according to the degree of loss Figure 1 B. We selected the top 200 genes with the most and least loss and performed pathway enrichment. The results showed that these genes were mainly enriched in the cell cycle pathway, ubiquitination pathway, DNA damage repair pathway, etc. The results refer to Figure 1 C. We used these pathway genes and the Top 200 important genes as genes for subsequent verification.

[0047] After pathway enrichment analysis, 16 gene targets and 12 small molecule inhibitors were selected for further validation in this example. First, we combined small molecule inhibitors with the CDK4 / 6 inhibitor Abemaciclib. These inhibitors include BAP1, PLK1, EZH2, DNA methyltransferase, HDAC, GSK3B, GLI pathway, Caspase, RUNX2 and NOTCH pathway, refer to Figure 2 A. Each drug was used in combination at 5 different concentrations. The combination index CI was calculated, and a CI value < 0 indicated a significant synergistic effect. The results showed that CDK4 / 6 had a good combination effect with HDAC, PLK1, and BAP1 inhibitors, with CI < 0, among which BAP1 inhibitors showed the best synergistic effect. To further validate these targets, we designed siRNA to knock down specific targets in SNU739 cells. Two siRNAs were designed for each target, and we tested the sensitivity changes to CDK4 / 6 inhibitors in control cells and cells with knockdown targets, respectively. Figure 2 B. We found that knocking down certain genes, including BAP1, SETDB1, and MYBL2, increased sensitivity to CDK4 / 6 inhibitors, among which BAP1 showed the highest degree of sensitivity.

[0048] We further verified the effect of BAP1 reduction on the sensitivity of liver cancer cell lines to CDK4 / 6 inhibitors. We used shRNA to knock down BAP1, and used immunoblotting to verify the knockdown effect. Figure 3 A. Our experimental results consistently showed that the sensitivity of liver cancer cell lines to CDK4 / 6 inhibitors was significantly increased when BAP1 was reduced. Figure 3 B. The synergistic inhibitory effect of the combined use of BAP1 inhibitor and CDK4 / 6 inhibitor abemaciclib on multiple liver cancer cell lines was also studied. In SNU739, SNU387, HUCCT1 and HUH7 cell lines, the combined use of abemaciclib and BAP1 inhibitor can more significantly inhibit the growth of tumor cells, see Figure 3 C, The Bliss model method was applied to calculate the synergy score, and it was found that at multiple drug concentrations, the synergy scores of the four cell lines were all >10. The combined use of abemaciclib can significantly inhibit the growth of tumor cells.

[0049] On this basis, we further explored whether the combined use of abemaciclib and inhibition of BAP1 could enhance this effect. Flow cytometry results showed that abemaciclib monotherapy could block the G1 phase of SNU739, SNU387, HUCCT1 and HUH7 liver cancer cell lines. The group using abemaciclib and inhibition of BAP1 showed more obvious cell cycle arrest, and the G1 phase arrest effect was stronger. Figure 4 .

[0050] The subsequent study further investigated the therapeutic effect of combined use of BAP1 knockdown and abemaciclib, and conducted a nude mouse subcutaneous transplant tumor drug sensitivity experiment. HUCCT1 cells were used, one group had BAP1 knocked out, and the other group had not. After transplantation into nude mice, the tumor volume was waited until it reached 100-150mm 3 The nude mice were randomly divided into four groups, including the control group, the abemaciclib group, the BAP1 knockdown group, and the BAP1 knockdown combined with abemaciclib group. Figure 5 A. The drug was administered daily for 30 consecutive days. The results showed that the tumor volume of the control group and the combined drug administration group after BAP1 knockdown was significantly reduced. Figure 5 BC.

[0051] To further explore the role of BAP1 deficiency in sensitizing liver cancer cells in human samples, in situ liver cancer tissues were collected from liver cancer patients and cultured into patient-derived organoids. Figure 6 A. By comparing with BAP1 wild-type wt organoids (O1, O2, O3), we found that BAP1 gene-deficient organoids (04, O5, O6) were significantly more sensitive to abemaciclib, see Figure 6 B. Specifically, in BAP1 wt organoids, the IC50 values ​​of abemaciclib were 19.55μM, 20.03μM, and 23.52μM, respectively; while in BAP1-deficient organoids, the IC50 values ​​of abemaciclib were 10.79μM, 12.1μM, and 9.05μM, respectively. This suggests that BAP1 deficiency may increase the sensitivity of liver cancer cells to abemaciclib, providing a new direction for the clinical application of this drug.

[0052] To further study the clinical significance of dual inhibition of BAP1 and cell cycle in primary liver cancer, a survival analysis based on the TCGA database was conducted, and a series of primary liver cancer samples were selected for study. First, the expression of CDK4 and BAP1 in primary liver cancer and hepatocellular carcinoma, including subtypes such as hepatocellular carcinoma and intrahepatic cholangiocarcinoma, was analyzed, and the effect of the combined expression of the two on patient survival was further studied. The results showed that in all groups, the survival rate of patients who simultaneously expressed low levels of CDK4 and BAP1 was significantly higher than that of other groups. Figure 7 A. To further explore this association, we divided TCGA patients into four groups: BAP1 low expression group, CDK4 low expression group, BAP1 and CDK4 low expression group, and BAP1 and CDK4 high expression group. The results showed that the prognosis of patients in the BAP1 and CDK4 low expression group was significantly better than that of the other three groups, while the prognosis of patients in the BAP1 and CDK4 high expression group was the worst. Figure 7 B.

[0053] Example 2: Replace abemaciclib in Example 1 with apatinib, and keep the rest unchanged.

[0054] Example 3: Replace abemaciclib in Example 1 with palbociclib, and keep the rest unchanged.

[0055] Example 4: The liver cancer specimen in Example 1 was replaced with breast cancer, and the rest remained unchanged.

[0056] Example 5: The liver cancer specimen in Example 1 was replaced with gastric cancer specimen, and the rest remained unchanged.

[0057] Figure 1 The specific parts refer to: A. Schematic diagram of CRISPR knockout screening of CDK4 / 6 inhibitor synergistic targets based on CRISPR whole genome library; B. DMSO group and CDK4 / 6 inhibitor group cell beta-score difference ranking diagram; the blue dots represent potential synergistic targets of CDK4 / 6 inhibitors (statistically significant points FDR < 0.05), and the red dots represent CDK4 / 6 inhibitor resistance targets (statistically significant points FDR < 0.05); C. Reactome pathway enrichment analysis diagram for potential CDK4 / 6 inhibitor synergistic targets and resistance genes in the screening results.

[0058] Figure 2 The parts indicate: A. Small molecule inhibitor validation, B. siRNA knockdown target validation.

[0059] Figure 3Indicated in each part: B. The clone formation experiment showed that knocking down BAP1 made the liver cancer cell line more sensitive to CDK4 / 6 inhibitors under long-term CDK4 / 6 inhibitor treatment; C. The cell survival rate after 72 hours of combined use of different concentrations of abemaciclib and BAP1-IN-1 in SNU739, SNU387, HUCCT1 and HUH7 cells was detected by CTG; the combination index of abemaciclib and BAP1-IN-1 was calculated by synerfinder software. Among them, synergy score>10 means that the two have a synergistic effect when used in combination.

[0060] Figure 4 The following sections indicate: A. Cell cycle distribution in SNU739, SNU387, HUCCT1 and HUH7 cells treated with abemaciclib (500 nM), BAP1 knockdown or BAP1 knockdown followed by abemaciclib for 48 hours as measured by flow cytometry.

[0061] Figure 5 Indications of each part: A. Schematic diagram of subcutaneous tumor formation in nude mice; HUCCCT1 cells were inoculated subcutaneously in nude mice, and when the tumor volume reached approximately 100-150 mm3, they were evenly divided into 4 groups: control group; abemaciclib group (dosage 50 mg / kg), BAP1 knockdown group; BAP1 knockdown plus abemaciclib group (dosage 50 mg / kg); 8 mice in each group, and the dosing regimen was daily oral administration for 30 consecutive days; B. Representative pictures of tumor transplants; C. Changes in tumor volume in the control group; abemaciclib group (dosage 50 mg / kg), BAP1 knockdown group; BAP1 knockdown plus abemaciclib group (dosage 50 mg / kg) after 30 consecutive days of administration.

[0062] Figure 6 The parts indicate: A. Organoids derived from tumor tissue of liver cancer patients; B. Drug sensitivity curve of organoids to CDK4 / 6 inhibitors.

[0063] The above examples and various figures show that the higher the degree of loss, the more significant the synergistic effect. Small molecule inhibitors and siRNA knockdown of the BAP1 target both show significant synergistic effects with CDK4 / 6 inhibitors, and BAP1 is the highest-ranked synergistic target gene in CRISPR screening. Therefore, the marker BAP1 was screened out to study its synergistic mechanism with CDK4 / 6 inhibitors; and the results showed that the prognosis of patients in the group with low expression of both BAP1 and CDK4 was significantly better than that of the other three groups, while the prognosis of patients in the group with high expression of both BAP1 and CDK4 was the worst, refer to Figure 7B, which means that combined inhibition of CDK4 and BAP1 may have potential clinical significance in improving patient survival, and this dual inhibition strategy may become a promising treatment method, so the use of CDK4 / 6 inhibitors in the manufacture of drugs for the treatment of cancers with BAP1 markers has good prospects.

[0064] Finally, it should be noted that the above is only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred arrangement scheme, a person skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. Use of a CDK4 / 6 inhibitor in the manufacture of a drug for treating cancer marked by BAP1, wherein: The cancer is selected from liver cancer, gastric cancer, endometrial cancer, HER2-negative breast cancer, and melanoma; The CDK4 / 6 inhibitor is selected from agents or compounds capable of inhibiting the transcription, expression, or function of the BAP1 gene; or inhibitors capable of targeting BAP1 or antibodies / immunologically active fragments capable of binding to BAP1 protein products, or pharmaceutically acceptable carriers and pharmaceutical compositions; And the CDK4 / 6 inhibitor is selected from palbociclib, ribociclib, abemaciclib, pembrolizumab, letrozole, apatinib, everolimus and fulvestrant.

2. The use according to claim 1, characterized in that: The CDK4 / 6 inhibitor is selected from apatinib, palbociclib, and abemaciclib.

3. The use according to claim 1, characterized in that: The drug sensitivity marker is RNA or its reverse transcribed cDNA, or protein.

4. The use according to claim 3, characterized in that: The drug sensitivity marker is BAP1.

5. The use according to claim 4, characterized in that: The drug sensitivity marker BAP1 was screened by CRISPR knockout based on the CRISPR whole genome library.

6. The use according to claim 1, characterized in that: The carrier comprises at least one of lactose, dextrose, sucrose, sorbitol, mannitol, starch, gum arabic, calcium phosphate, alginate, gelatin, calcium silicate, microcrystalline cellulose, polyvinyl pyrrolidone, cellulose, water, syrup, methylcellulose, methyl hydroxybenzoate, propyl hydroxybenzoate, talc, magnesium stearate and mineral oil.

7. The use according to claim 1, characterized in that: The pharmaceutical composition comprises at least one of a lubricant, a wetting agent, a sweetener, a flavoring agent, an emulsifier, a suspending agent, and a preservative.

8. Application of CDK4 / 6 inhibitors in the manufacture of reagents for drug sensitivity marker detection.

9. The use according to claim 8, characterized in that: The drug sensitivity test includes drug resistance test and drug sensitivity test.

10. The use according to claim 8, characterized in that: The detection methods of the reagents for drug sensitivity marker detection include: RT-PCR, fluorescent quantitative PCR, mRNA Sequencing, mRNA array detection technology, immunohistochemistry, immunofluorescence, Western blot, ELISA, flow cytometry detection, immunological detection, and chemical detection.

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