Application of CDK9 as target spot in preparation of medicine for preventing and treating oral leukoplakia canceration

Abstract

The invention belongs to the technical field of biological medicines, and particularly relates to application of CDK9 as a target spot in preparation of a medicine for preventing and treating oral leukoplakia canceration. The invention proves that the phenomenon of transcriptional activity increase and the characteristic of transcription addiction exist in the oral leukoplakia canceration process, and a driving factor cyclin-dependent kinase 9 (CDK9) closely related to oral leukoplakia transcriptional disorder is screened out. Moreover, a molecular mechanism of CDK9 driving oral leukoplakia transcription addiction is further clarified, an important role of CDK9 in an oral leukoplakia canceration process is clarified, and transcription addiction of oral leukoplakia cells can be effectively inhibited through targeted intervention of activity or expression level of CDK9, so that canceration potential of oral leukoplakia can be effectively prevented and treated.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedicine, and particularly relates to the application of CDK9 as a target in the preparation of drugs for preventing and treating oral leukoplakia carcinogenesis. Background Art

[0002] Targeting cell transcriptional addiction is a new treatment strategy for intervening in diseases such as tumors recently: The transcriptional cycles occurring in normal cells are strictly regulated by mechanisms such as negative regulation by transcription cycle-dependent kinases and transcriptional phosphatases. In malignant tumors, genomic and epigenetic alterations, etc., can induce carcinogenic transcriptional dysregulation, resulting in defective gene expression, making tumor cells exhibit the characteristic of "transcriptional addiction". At present, the strategy of intervening in "transcriptional addiction" based on transcription cycle-dependent kinases as targets has shown good anti-tumor potential.

[0003] Oral leukoplakia is the most common oral mucosal precancerous disease, and there is still a lack of effective targets for preventing its malignancy: Oral leukoplakia (OLK) is the most common potentially malignant disorder of the oral mucosa, with a high risk of carcinogenesis. Epidemiological evidence shows that more than 70% of patients with oral squamous cell carcinoma (OSCC) develop from the malignancy of OLK. As a precancerous lesion, the carcinogenesis mechanism of oral leukoplakia involves multiple factors and abnormal multiple pathways. In the prevention and treatment strategy of oral leukoplakia carcinogenesis, it is necessary to consider multiple dimensions such as molecular targeted therapy, epigenetic therapy, immune microenvironment regulation, and microbial intervention.

[0004] However, the potential of targeting transcriptional addiction to prevent and treat the malignancy of oral leukoplakia has not been clarified: Precancerous lesions are intermediate stages with a high risk of carcinogenesis. They have already shown abnormal changes in histopathology, gene expression, etc., and possess characteristics similar to those of their corresponding cancers. Therefore, precancerous lesions may also possess the characteristics of transcriptional addiction. However, current domestic and foreign scholars lack research on whether many precancerous lesions have the characteristics of transcriptional addiction and targeting transcriptional addiction to prevent the malignant progression of precancerous diseases. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects and deficiencies in the prior art and provide the application of CDK9 as a target in the preparation of drugs for preventing and treating oral leukoplakia carcinogenesis. By clearly targeting and intervening in CDK9, the "transcriptional addiction" of oral leukoplakia cells can be significantly inhibited, thereby effectively inhibiting the risk of oral leukoplakia carcinogenesis, and providing an important theoretical basis for the research on developing effective cancer treatment strategies and drug screening, etc.

[0006] To achieve the above purpose, the technical solutions adopted by the present invention include:

[0007] In a first aspect, the present invention provides the use of a CDK9 inhibitor in the preparation of a drug for preventing and / or treating oral leukoplakia carcinogenesis.

[0008] The present invention has studied the transcriptional addiction characteristics and molecular mechanisms of oral leukoplakia, a common potentially malignant disorder of the oral mucosa, and found that there are phenomena of increased transcriptional activity and "transcriptional addiction" characteristics during the carcinogenesis of oral leukoplakia. Moreover, through experimental exploration, it has been found that highly expressed CDK9 mediates transcriptional addiction, thereby promoting the malignant progression of oral leukoplakia. Therefore, CDK9 plays an important role in the transcriptional regulation of oral leukoplakia, and the abnormal expression level thereof is closely related to the malignant transformation of oral leukoplakia. By targeting and intervening in the activity or expression level of CDK9, the "transcriptional addiction" of oral leukoplakia cells can be effectively inhibited, thereby effectively preventing and treating the carcinogenic potential of oral leukoplakia, providing a new molecular target and potential treatment strategy for preventing and treating the malignant transformation of oral leukoplakia.

[0009] Preferably, the CDK9 inhibitor includes at least one of a gene sequence, a small molecule compound, and a polypeptide that can reduce the expression level of CDK9.

[0010] Preferably, the small molecule compound includes LDC067.

[0011] Preferably, the gene sequence is CDK9 siRNA, and the siRNA is selected from any one of the following pairs (1)-(2):

[0012] (1) The nucleotide sequence of the sense strand of the siRNA is as shown in SEQ ID NO: 1, and the nucleotide sequence of the antisense strand is as shown in SEQ ID NO: 2;

[0013] (2) The nucleotide sequence of the sense strand of the siRNA is as shown in SEQ ID NO: 3, and the nucleotide sequence of the antisense strand is as shown in SEQ ID NO: 4.

[0014] The present invention uses a specific small molecule inhibitor (LDC067) and gene knockout (specific siRNA gene sequence) to target and intervene in the CDK9 activity and expression of oral leukoplakia (OLK) and oral squamous cell carcinoma (OSCC) cells. Through experimental exploration, it has been found that both LDC067 and CDK9 siRNA can significantly inhibit the expression level and / or activity of CDK9 in DOK cells and OSCC cells, reduce the activity of the transcriptional core complex RNA Pol II, thereby reducing the level of nascent RNA in the cells, and further effectively blocking the carcinogenesis of OLK.

[0015] More preferably, the nucleotide sequence of the sense strand of the siRNA is as shown in SEQ ID NO: 3, and the nucleotide sequence of the antisense strand is as shown in SEQ ID NO: 4.

[0016] Preferably, the CDK9 inhibitor can reduce the activity of the transcriptional core complex RNA Pol II and inhibit cellular transcriptional addiction.

[0017] Preferably, the diseases after oral leukoplakia carcinogenesis include oral squamous cell carcinoma.

[0018] In a second aspect, the present invention provides the use of CDK9 as a target in the preparation of a drug for preventing and / or treating oral leukoplakia carcinogenesis.

[0019] In a third aspect, the present invention provides the use of CDK9 as a drug target for screening drugs for preventing and / or treating oral leukoplakia carcinogenesis.

[0020] In a fourth aspect, the present invention provides a drug for preventing and / or treating oral leukoplakia carcinogenesis, the drug comprising LDC067 and / or a gene sequence, the gene sequence being CDK9 siRNA, and the siRNA being selected from any one pair of the following (1)-(2):

[0021] (1) The nucleotide sequence of the sense strand of the siRNA is as shown in SEQ ID NO: 1, and the nucleotide sequence of the antisense strand is as shown in SEQ ID NO: 2;

[0022] (2) The nucleotide sequence of the sense strand of the siRNA is as shown in SEQ ID NO: 3, and the nucleotide sequence of the antisense strand is as shown in SEQ ID NO: 4.

[0023] Preferably, the drug further comprises a pharmaceutically acceptable excipient.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] The present invention confirms the phenomenon of increased transcriptional activity and the "transcriptional addiction" feature during the carcinogenesis of oral leukoplakia, and screens out the cyclin-dependent kinase 9 (CDK9), a driving factor closely related to transcriptional dysregulation in oral leukoplakia. Furthermore, the molecular mechanism by which CDK9 drives transcriptional addiction in oral leukoplakia is further elucidated, and its important role in the carcinogenesis of oral leukoplakia is clarified. By targeting and intervening in the activity or expression level of CDK9, the "transcriptional addiction" of oral leukoplakia cells can be effectively inhibited, thereby effectively preventing and treating the carcinogenic potential of oral leukoplakia. Therefore, the present invention not only reveals the molecular basis of oral leukoplakia carcinogenesis, but also provides a new targeted treatment plan for clinical practice, and is expected to become an important breakthrough for preventing and treating oral leukoplakia carcinogenesis. Description of the Drawings

[0026] Figure 1 It is a result diagram for exploring transcriptional dysregulation during the carcinogenesis of OLK in Example 1; wherein, Figure 1A is the volcano plot of differentially expressed genes; Figure 2 B is the volcano plot of transcription addiction genes with differential expression; Figure 1 C is the diagram of the detection of newly generated RNA in cells; Figure 1 D is the diagram of the detection of chromatin openness in cells; Figure 1 E is the diagram of the expression of p-RNAPol II (Ser2) in cells;

[0027] Figure 2 are the result diagrams for exploring the correlation between high expression of CDK9, high activity of RNAPol II and poor prognosis of OSCC in Example 2; among them, Figure 2 A is the diagram of the expression of CDK9 in each clinical stage of OSCC;

[0028] Figure 2 B is the diagram of the impact of CDK9 on the survival of OSCC patients; Figure 2 C is the correlation result diagram of CDK9 and RNAPol II (POLR2A) in the TCGA-OSCC dataset; Figure 2 D-E are the expression result diagrams of CDK9 and p-RNAPol II (Ser2) in oral mucosa tissues; Figure 2 F is the correlation result diagram of the expression of CDK9 and p-RNA Pol II (Ser2) in oral mucosa tissues; Figure 2 G-H are the expression and correlation result diagrams of CDK9 and p-RNA Pol II (Ser2) in cells; Figure 2 I is the interaction result diagram of CDK9 and p-RNAPol II (Ser2) in DOK and SCC15 cells;

[0029] Figure 3 are the result diagrams for exploring that CDK9 inhibition can reverse the upregulation of RNAPol II-dependent transcription in Example 3; among them, Figure 3 A-B are the result diagrams of the effects of CDK9 siRNA and LDC067 on the expression of CDK9 and p-RNA Pol II (Ser2) in cells; Figure 3 C-D are the result diagrams of the effects of CDK9 inhibition on the phosphorylation of CDK9 and RNA Pol II in DOK and OSCC cells; Figure 3 E-F are the effects of CDK9 inhibition on the level of newly generated RNA in cells; Figure 3 G is the result diagram of the effect of CDK9 inhibition on chromatin openness in cells;

[0030] Figure 4 are the comparison diagrams of the transfection efficiencies of two siRNAs against DOK, SCC15 and HSC3 cells in Example 3;

[0031] Figure 5Results graph for exploring that CDK9 inhibition can induce apoptosis in DOK, SCC15, and HSC3 cells in Example 3; wherein, Figure 5 A is the results graph of the effect of LDC067 on cell viability; Figure 5 B is the results graph of the effect of LDC067 on apoptosis; Figure 5 C-D are the results graphs of the effect of CDK9 inhibition on the expression levels of apoptosis-related proteins.

[0032] Figure 6 Results graph for exploring that CDK9 inhibition can effectively block 4NQO-induced oral mucosal carcinogenesis in mice in Example 3; wherein, Figure 6 A is the experimental design graph of LDC067 targeting and intervening CDK9 to prevent and treat OLK carcinogenesis in animals; Figure 6 B is the results graph of the body weight changes of mice in each group; Figure 6 C is the survival graph of mice in each group; Figure 6 D is the results graph of the tongue lesion area of mice in each group; Figure 6 E-F are representative HE staining graphs of tongue lesions in mice;

[0033] Figure 6 G is the expression results graph of p-RNA Pol II(Ser2), Ki-67, MCL-1, and BCL-2 in mouse tongue tissues.

[0034] Figure 7 Results graph for the analysis of transcriptional core factors in Example 2; wherein, Figure 7 A is the expression level graph of tCDKs in different clinical stages in the TCGA-OSCC dataset; Figure 7 B is the Kaplan-Meier survival curve graph of the total population of tCDKs in the TCGA-OSCC dataset; Figure 7 C is the expression level graph of tCDKs in HaCaT, DOK, CAL27, UM1, SCC15, and HSC3 cells. Detailed implementation manners

[0035] To make the objectives, technical solutions, and effects of the present invention clearer and more definite, the present invention will be further described in detail below with reference to the embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0036] Unless otherwise specified, the reagents used in the embodiments are all conventional reagents in the art and can be obtained through commercial channels. The experimental operations not specifically described in the embodiments are all conventional operations in the art or operations that can be understood or known by those skilled in the art according to the existing technology or common general knowledge they have mastered.

[0037] The nucleotide sequences of the two CDK9 siRNAs (siRNA-1 and siRNA-2) involved in the examples are shown in Table 1.

[0038] Table 1

[0039]

[0040] Example 1. Identifying the molecular characteristics of "transcriptional addiction" at each stage of the normal-OLK-OSCC evolution

[0041] In this example, the transcriptome data of the mouse model and the transcriptome data of OLK and OSCC in the network database were explored, and the cell line was used to verify the cell nascent RNA, chromatin openness and p-RNA Pol II (Ser2) expression in vitro.

[0042] (1) Experimental method:

[0043] Construction of mouse model: C57BL / 6 mice at 4-5 weeks of age, 6 mice in each of the control group, OLK group and OSCC group. The OLK group and OSCC group were induced with 4NQO, and were fed with 4NQO (100 mg / L) special drinking water for 16 weeks and 20 weeks respectively, while the control group was fed with ordinary drinking water; mouse tongue tissue samples were obtained.

[0044] Transcriptome sequencing: After obtaining the tissue samples, in cooperation with OE Biotech, transcriptome sequencing was used to detect the gene expression in the tissues. Through raw data filtering and quality control, reference genome alignment, alignment uniformity analysis, saturation analysis, sample correlation analysis, expression level analysis, differential gene analysis; hierarchical clustering analysis was performed on the selected differentially expressed genes; the genes expressed in this project were annotated by integrating multiple databases (ENSEMBL, NCBI, Uniprot, GO, KEGG), and differential gene GO enrichment analysis, pathway enrichment analysis, disease enrichment analysis, etc. were completed.

[0045] Bioinformatics analysis: The data of oral cancer patients in the TCGA and GEO databases were obtained, differential gene analysis was performed, and the number of genes with up-regulated expression among the differential genes was compared. Through literature review, 38 genes closely related to transcriptional addiction were sorted out and summarized, and the expression differences of transcriptional addiction genes were analyzed.

[0046] (2) Experimental results:

[0047] Analysis was performed through the GEO and TCGA databases. The dataset GSE30784 contained 45 healthy controls and 17 oral leukoplakia patient samples. The results of differential expression analysis of this dataset showed that 2,002 genes were upregulated. In TCGA-OSCC (including 32 adjacent cancer tissues and 362 tumor tissues), 9,476 genes were upregulated. Meanwhile, a C57BL / 6 mouse OLK carcinogenesis model was constructed by special drinking water containing 4NQO (100 mg / L) for 16 weeks and transcriptome sequencing was performed. Compared with the control group, the number of upregulated genes in the 4NQO-induced group was 4,425 ( Figure 1 A). The number of highly expressed genes can to a certain extent reflect transcriptional activity. The research results suggest that transcriptional dysregulation occurs during the carcinogenesis of OLK. Moreover, the differential expression of 38 genes closely related to transcriptional addiction was analyzed in the three datasets. In the GSE30784 dataset, 8 genes (21.1%) were differentially expressed in oral leukoplakia patients. In the TCGA-OSCC group, 22 genes (57.9%) were differentially expressed in OSCC patients. In the mouse OLK carcinogenesis model, 16 genes (42.1%) were differentially expressed ( Figure 1 B), and most of the upregulated transcription addiction genes can promote transcription, while most of the downregulated transcription addiction genes have an inhibitory effect on transcription. Subsequently, the results of cell experiments proved that compared with human normal oral keratinocytes HOK and human normal epidermal cells HaCaT cells, the content of nascent RNA in the precancerous cell line DOK, OSCC cells SCC15 and HSC3 cells was significantly increased ( Figure 1 C), and chromatin openness was significantly enhanced ( Figure 1 D). Moreover, RNAPol II had higher activity in DOK and OSCC cells ( Figure 1 E). Therefore, the above results confirmed that there is an increase in transcriptional activity and the characteristic of "transcriptional addiction" during the carcinogenesis of OLK.

[0048] Example 2. Identifying the important driving molecule CDK9 for OLK transcriptional addiction

[0049] In this example, the important driving role of CDK9 in OLK "transcriptional addiction" was clarified through database mining, human clinical samples, and in vitro cell experiments at multiple levels and from multiple perspectives.

[0050] (1) Experimental method:

[0051] First, perform transcriptional core factor analysis in the database to find the driver molecules with differential expression in the early clinical stage of OSCC, and conduct corresponding survival analysis and correlation analysis with RNAPol II. Subsequently, evaluate the expression levels of CDK9 and p-RNAPol II (Ser2) in 7 normal oral mucosa tissues, 22 OLK, and 8 OSCC lesion samples (all the patient tissue samples are from the Department of Oral Mucosa, School of Stomatology, Sun Yat-sen University) by immunohistochemistry, and explore the association between the two and the progression of oral mucosa carcinogenesis.

[0052] Moreover, further verify the expression levels of CDK9 and p-RNA Pol II (Ser2), and the correlation between CDK9 and p-RNAPol II (Ser2) in human normal epidermal cells HaCat, precancerous cell line DOK, and OSCC cells CAL27, HSC3, UM1, SCC15 through relevant cell line experiments. Subsequently, treat DOK and OSCC cell line SCC15 with CDK9 specific inhibitor LDC067 (10 μM) or CDK9 siRNA for 48 h. Compare the expression levels and activities of CDK9 and transcriptional core complex RNAPol in DOK and SCC15 cells, as well as the changes in nascent RNA and chromatin openness in cells after interfering with CDK9 activity.

[0053] (2) Experimental results:

[0054] In the analysis of transcriptional core factors in the database, it was found that CDK9 had differential expression in the early clinical stage of OSCC ( Figure 2 A), and the overall survival rate of OSCC patients with high CDK9 expression was lower ( Figure 2 B), suggesting that CDK9 plays an important role in the carcinogenesis of OLK. The process of transcriptional core factor analysis is shown in Figure 7 . TCGA-OSCC data analysis showed that there was a weak correlation between the expression level of CDK9 and RNA Pol II ( Figure 2 C). Subsequently, in this example, the expression levels of CDK9 and p-RNA Pol II (Ser2) in 7 normal oral mucosa tissues, 22 OLK, and 8 OSCC lesion samples were evaluated, and it was confirmed that the expression levels of CDK9 and p-RNAPol II (Ser2) gradually increased with the progression of oral mucosa carcinogenesis ( Figure 2 D-E), and there was a correlation between the two ( Figure 2 F), suggesting that CDK9 is an important driver factor for transcriptional dysregulation of the disease. Detection in HaCaT, DOK, and OSCC cell lines found that the expression of CDK9 was up-regulated in DOK and OSCC cells ( Figure 2G), and there was a correlation between the expression levels of CDK9 and p-RNAPol II (Ser2) ( Figure 2 H). Subsequently, this study used Co-IP to detect a direct interaction between CDK9 and p-RNA Pol II (Ser2) in DOK and SCC15 cells ( Figure 2 I). The above results all confirm that high expression of CDK9 is closely related to the "transcriptional addiction" in OLK carcinogenesis.

[0055] Example 3. Exploration of whether targeting CDK9 has therapeutic potential for preventing and treating OLK carcinogenesis

[0056] This example uses cell lines and animal models to inhibit CDK9 activity using a dual strategy of gene knockout and specific inhibitors to explore the potential of targeted inhibition of CDK9 to prevent the occurrence and development of OLK.

[0057] (1) Experimental methods:

[0058] First, CDK9 expression in DOK and SCC15 cells was targeted with LDC067 and two CDK9 siRNAs (siRNA-1 and siRNA-2). Cell viability was assessed using CCK8 assays, and apoptosis was detected by Annexin V-PI flow cytometry and Western blot. Furthermore, a 4NQO (100 mg / L) drinking water animal model was established in 30 4- to 5-week-old C57BL / 6 mice. At 14 weeks of age, mice fed with 4NQO drinking water were intraperitoneally injected with varying concentrations of LDC067 three times weekly. After two weeks of simultaneous 4NQO drinking water and LDC067 injections, the 4NQO drinking water was discontinued (for a total of 16 weeks) and replaced with regular drinking water. LDC067 injections were then continued for another four weeks (for a total of six weeks). After one week of observation, the mice were sacrificed and samples collected. Body weight and tongue lesion area were assessed, and tongue tissues were stained with hematoxylin and eosin and immunohistochemistry.

[0059] LDC067 Dosing Regimen: LDC067 is poorly soluble in water. Animal experiments used a solvent of 10% DMSO + 40% PEG-300 + 5% Tween-80 + 45% saline. Administration was by intraperitoneal injection three times a week, with each injection volume being 0.2 ml. ① Control group: solvent; ② Low-concentration group: 7.5 mg / kg; ③ High-concentration group: 15 mg / kg.

[0060] (2) Experimental results:

[0061] 1. In vitro cell experiments showed that targeted intervention of CDK9 can effectively inhibit the "transcriptional addiction" of OLK cells

[0062] Specific small molecule inhibitors (LDC067) and gene knockout were used respectively to target and intervene in the CDK9 activity and expression in DOK and OSCC cells. The study found that both LDC067 and two CDK9 siRNAs could significantly inhibit the expression level and / or activity of CDK9 in DOK cells and SCC15 cells, reduce the activity of the transcriptional core complex RNA Pol II, and decrease the level of nascent RNA in cells ( Figure 3 ); and the transfection efficiency was detected by qRT-PCR, and it was found that the transfection effect of siRNA-2 was better than that of siRNA-1, and it could better reduce the transcriptional level of CDK9 in cells ( Figure 4 ). The phosphorylation of RNA Pol II Ser2 mediated by CDK9 is the key to promoting transcriptional elongation, and the research results directly show that the highly expressed CDK9 is closely related to the occurrence and development of OLK carcinogenesis, and is an important driving molecule of "transcriptional addiction" in the process of OLK carcinogenesis. In addition, in vitro studies found that inhibiting the activity or expression of CDK9 in DOK and OSCC cells could inhibit cell proliferation and induce apoptosis ( Figure 5 A-B), showing an increase in the expression level of cleaved-PARP and a decrease in the expression levels of MCL-1 and BCL-2 ( Figure 5 C-D).

[0063] 2. In vivo animal experiments confirmed that targeting and intervening in CDK9 could effectively block OLK carcinogenesis

[0064] A C57BL / 6 mouse OLK carcinogenesis model was constructed by feeding with 4NQO (100 mg / L) special drinking water for in vivo research. When the 4NQO special drinking water was fed for 14 weeks, different concentrations of LDC067 were intraperitoneally injected, 3 times a week. After 2 weeks of simultaneous 4NQO special drinking water and intraperitoneal injection of LDC067, the 4NQO special drinking water was stopped (for a total of 16 weeks), replaced with ordinary drinking water, and the intraperitoneal injection of LDC067 was continued for 4 weeks (for a total of 6 weeks). After the end, the mice were observed for 1 week and then sacrificed for tissue collection ( Figure 6 A). The results showed that the body weights of the mice in the LDC067 treatment group were stable, while the body weights of the untreated group of mice continued to decline ( ​ B). The survival status of the mice in the treatment group was better than that of the untreated group ( ​ C). By comparing the lesion areas of the tongues of the mice in each group, it was found that LDC067 at 15 mg / kg could significantly reduce the tongue lesions of the mice ( ​ D). HE staining was performed on the tongue tissues, and the results showed that the proportion of mice with moderate to severe epithelial dysplasia or OSCC in the treatment group was significantly lower than that in the untreated group, indicating that LDC067 could effectively delay the process of oral mucosal carcinogenesis in mice ( ​E-F). Immunohistochemical staining results showed that the expression levels of p-RNA Pol II (Ser2), Ki-67, MCL-1, and BCL-2 in the tongue tissues of the treatment group mice were significantly decreased ( ​ G). The results of in vivo experiments showed that treating model mice with the CDK9 small molecule specific inhibitor LDC067 at 15 mg / kg could significantly reduce the degree of oral epithelial dysplasia in mice and inhibit the progression of OLK carcinogenesis.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. Use of a CDK9 inhibitor in the preparation of a drug for preventing and / or treating oral leukoplakia carcinogenesis.

2. Use of CDK9 as a target in the preparation of a drug for preventing and / or treating oral leukoplakia carcinogenesis.

3. Use of CDK9 as a drug target for screening for preventing and / or treating oral leukoplakia carcinogenesis.

4. The application according to any one of claims 1-3, characterized in that The diseases after oral leukoplakia carcinogenesis include oral squamous cell carcinoma.

5. The application according to claim 1, characterized in that The CDK9 inhibitor includes at least one of a gene sequence, a small molecule compound, and a polypeptide that can reduce the expression level of CDK9.

6. The application according to claim 5, wherein The small molecule compound includes LDC067.

7. The application according to claim 5, characterized in that, The gene sequence is CDK9 siRNA, and the siRNA is selected from any one pair of the following (1)-(2): (1) The nucleotide sequence of the sense strand of the siRNA is as shown in SEQ ID NO: 1, and the nucleotide sequence of the antisense strand is as shown in SEQ ID NO: 2; (2) The nucleotide sequence of the sense strand of the siRNA is as shown in SEQ ID NO: 3, and the nucleotide sequence of the antisense strand is as shown in SEQ ID NO:

4.

8. The application according to claim 1, characterized in that The CDK9 inhibitor can reduce the activity of the transcription core complex RNA Pol II and inhibit cell transcriptional addiction.

9. A drug for preventing and / or treating oral leukoplakia from canceration, characterized in that, The drug includes LDC067 and / or a gene sequence, the gene sequence is CDK9 siRNA, and the siRNA is selected from any one pair of the following (1)-(2): (1) The nucleotide sequence of the sense strand of the siRNA is as shown in SEQ ID NO: 1, and the nucleotide sequence of the antisense strand is as shown in SEQ ID NO: 2; (2) The nucleotide sequence of the sense strand of the siRNA is as shown in SEQ ID NO: 3, and the nucleotide sequence of the antisense strand is as shown in SEQ ID NO:

4.

10. The drug according to claim 9, wherein, The drug further includes a pharmaceutically acceptable excipient.

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