Application of FASN inhibitor in preparation of medicine for treating KAT2B low-expression renal cell carcinoma

Abstract

The invention relates to the technical field of biomedicine, and discloses application of an FASN inhibitor in preparation of a medicine for treating KAT2B low-expression renal cell carcinoma. According to the invention, development of a lipid metabolism related biomarker is realized, it is determined that the biomarker is an independent prognosis factor KAT2B in RCC, high methylation of a KAT2B promoter region causes down-regulation of expression of the biomarker, then lipid generation and development of the RCC are enhanced, a mechanism of KAT2B / HDAC5 / LSD1 / FASN axis for inhibiting the lipid generation and development of the RCC in vivo is proposed for the first time, KAT2B is acetylated at a K726 site of HDAC5, and KAT2B and LSD1 / FASN are used for inhibiting the lipid generation and development of the RCC. The FASN inhibitor can be used for inhibiting cancer cell targeting and promoting extranuclear transport of the FASN inhibitor, so that the FASN inhibitor and LSD1 cannot form a compound in a cell nucleus, the histone methylation level is increased, FASN expression is reduced, and a new thought is provided for research and development of products for inhibiting cancer cell targeting through the FASN inhibitor.

Description

Technical Field

[0001] This invention relates to the field of biomedical technology, specifically to the application of FASN inhibitors in the preparation of drugs for treating renal cell carcinoma with low KAT2B expression. Background Technology

[0002] Renal cell carcinoma (RCC) is a highly heterogeneous tumor with a complex genetic background, making its treatment challenging. Current main treatment approaches for RCC include targeted therapy and immune checkpoint inhibitors. Targeted therapies primarily include tyrosine kinase inhibitors (TKIs) and mTOR inhibitors, while immunotherapies include PD-1 and CTLA-4 monoclonal antibodies. However, these therapies often face drug resistance issues and have limited efficacy; therefore, further elucidating the molecular mechanisms of RCC is crucial for developing new therapeutic agents.

[0003] Existing research indicates that aberrant lipid metabolism exists in almost all tumors, and this metabolic abnormality promotes tumor progression. Tumor cells abnormally regulate lipid metabolic pathways to adapt to their rapid proliferation and changing energy demands. This aberrant lipid metabolism is particularly pronounced in recurrent lipomatosis (RCC), where tumor cells exhibit enhanced de novolipogenesis (DNL) and lipid uptake, while lipid degradation is inhibited. Lipid synthases such as fatty acid synthase (FASN) are highly expressed in various tumors, especially in RCC. However, the exact molecular mechanisms driving aberrant lipid deposition in RCC remain not fully understood. Summary of the Invention

[0004] The purpose of this invention is to provide the application of FASN inhibitors in the preparation of drugs for treating renal cell carcinoma with low KAT2B expression, so as to solve the technical problem that the molecular mechanism of FASN-related abnormal lipid deposition in RCC is unclear in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution: This invention provides the application of FASN inhibitors in the preparation of drugs for treating renal cell carcinoma with low KAT2B expression.

[0006] As a preferred embodiment of the present invention, the FASN inhibitor is used to inhibit abnormal lipid accumulation in cells or tissues with low KAT2B expression.

[0007] In a preferred embodiment of the present invention, the FASN inhibitor is the inhibitor TVB-2640.

[0008] This invention provides the application of KAT2B products in the preparation of products for screening or treating clear cell renal cell carcinoma.

[0009] As a preferred embodiment of the present invention, KAT2B overexpression inhibits abnormal lipid accumulation in clear cell renal cell carcinoma, while KAT2B low expression promotes abnormal lipid accumulation in clear cell renal cell carcinoma.

[0010] This invention provides the application of a product targeting KAT2B in the preparation of a product for screening or treating clear cell renal cell carcinoma. The KAT2B target is FASN, which promotes abnormal lipid accumulation in clear cell renal cell carcinoma. Inhibiting FASN can reverse the abnormal lipid accumulation caused by cells with low KAT2B expression.

[0011] As a preferred embodiment of the present invention, the application of the KAT2B / HDAC5 / LSD1 / FASN axis in the preparation of products for treating clear cell renal cell carcinoma is included; Specifically, KAT2B acetylates the K726 site of HDAC5, enhancing the binding of the K726 site to Exportin1 and promoting its extranuclear transport, thereby disrupting the assembly of the nuclear HDAC5-LSD1 complex, promoting histone methylation, and inhibiting FASN expression.

[0012] Compared with the prior art, the present invention has the following advantages: This invention discloses that FASN inhibitors are promising drugs for treating RCC or other tumors with low KAT2B expression, correcting abnormal lipid accumulation, effectively inhibiting RCC progression, and enhancing sensitivity to sunitinib. The inhibitor TVB-2640, whether used as a monotherapy or in combination with TKIs and immune checkpoint inhibitors, lays the foundation for its clinical application in the treatment of RCC patients with low KAT2B expression. This invention discloses the regulatory mechanism of KAT2B in RCC, namely the KAT2B / HDAC5 / LSD1 / FASN axis. KAT2B inhibits the formation of the HDAC5 / LSD1 complex and suppresses FASN generation by acetylating the K726 site of HDAC5 and promoting its extranuclear transport. This highlights the importance of HDAC5 acetylation and its subcellular localization changes in complex assembly, and provides a new molecular marker and therapeutic target. Attached Figure Description

[0013] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0014] Figure 1This invention provides a schematic diagram of the mechanism by which KAT2B regulates FASN expression; Figure 2 This invention provides statistical graphs of cell viability of ACHN cells with high KAT2B expression and Caki-1 cells with low KAT2B expression after treatment with TVB-2640; Figure 3 This invention provides statistical graphs of cell viability of 786O cells with high KAT2B expression and 769P cells with low KAT2B expression after treatment with TVB-2640; Figure 4 This invention provides two statistical charts of cell viability of primary RCC cells after treatment with TVB-2640; Figure 5 This invention provides a map showing the expression of KAT2B protein in RCC tissues extracted from three independent sites; Figure 6 Representative images of Caki-1 and ACHN 3D cultured after treatment with TVB-2640 (7.5 μM) are provided for this invention; Figure 7 Representative images of 786O and 769P 3D cultured after treatment with TVB-2640 (7.5 μM) are provided for this invention; Figure 8 Representative images of two organoids with different KAT2B expression levels after processing with TVB-2640 are provided for this invention; Figure 9 This provides representative images of PRO-1 staining in organoids for the present invention; Figure 10 This invention provides a statistical analysis diagram of PRO-1 stained positive regions; Figure 11 This invention provides a statistical chart of cell viability of parental ACHN and KAT2B stably knocked-down ACHN cells after treatment with TVB-2640; Figure 12 This invention provides a statistical graph of the cell viability of primary RCC cells with high KAT2B expression from patient No. 1 and primary RCC cells with KAT2B knockdown treated with TVB-2640. Figure 13 This invention provides images of subcutaneous xenografts formed from 786O cells with stable KAT2B knockdown after TVB-2640 treatment; Figure 14 This invention provides a tumor growth curve of subcutaneous xenograft tumors formed by KAT2B knockdown 786O cells under TVB-2640 treatment; Figure 15Representative images of colony formation of HK-2, ACHN, OSRC-2, 786O, A498, 769P and Caki-1 cells after treatment with different concentrations of TVB-2640 are provided for this invention. Figure 16 Statistical analysis graphs of the growth of HK-2, ACHN, OSRC-2, and 786O cells in the colony formation experiment are provided for this invention; Figure 17 Statistical analysis graphs of the growth of A498, 769P, and Caki-1 cells in the colony formation experiment are provided for this invention; Figure 18 Oil Red staining and statistical analysis of A498 and Caki-1 cells after stable KAT2B overexpression are provided for this invention. Figure 19 This invention provides a scatter plot showing the expression of KAT2B and FASN in 23 late-stage RCC samples and the correlation between their levels.

[0015] Figure 20 This invention provides cell growth curves after stable overexpression of KAT2B in A498 and Caki-1 and stable knockdown of KAT2B in 786O and 769P.

[0016] Figure 21 This invention provides a cloning diagram showing the stable overexpression of KAT2B in A498 and Caki-1 and the stable knockdown of KAT2B in 786O and 769P.

[0017] Figure 22 This invention provides a gross image of a tumor formed subcutaneously in BALB / c nu mice after stable overexpression of KAT2B in Caki-1.

[0018] Figure 23 This invention provides a representative image of Ki67 staining in subcutaneous tumors overexpressing KAT2B.

[0019] Figure 24 This invention provides in vivo imaging images of mice with a tumor tail vein injection metastasis model after stable overexpression of KAT2B in Caki-1.

[0020] Figure 25 This invention provides gross and HE-stained representative images of liver metastases in an in vivo tumor metastasis model. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] This invention provides the application of FASN inhibitors in the preparation of drugs for treating RCC with low KAT2B expression. Hypermethylation of the KAT2B promoter region leads to its downregulation, thereby enhancing lipid production and progression in RCC. Mechanistically, KAT2B undergoes acetylation at the K726 site of HDAC5, promoting its extranuclear transport and preventing it from forming a complex with LSD1 in the nucleus, resulting in increased histone methylation levels and downregulation of FASN expression. Figure 1 This diagram illustrates the mechanism by which KAT2B regulates FASN expression. In RCC, low KAT2B expression or loss leads to decreased acetylation levels at the HDAC5 K726 site, resulting in increased binding of HDAC5 to the exportin 1 protein. HDAC5 translocates from the nucleus to the cytoplasm, thus preventing it from forming a complex with or stabilizing LSD1 in the nucleus. This results in decreased histone methylation and increased FASN expression.

[0023] KAT2B is downregulated in advanced RCC and may be targeted by FASN inhibitors. Furthermore, FASN inhibitors have shown superior efficacy in RCC with low KAT2B expression compared to other cancer types.

[0024] KAT2B deficiency can promote lipid production in RCC by upregulating FASN expression, and KAT2B and FASN expression are negatively correlated in late-stage RCC samples. FASN inhibitors include IPI-91191, TVB-3166, and TVB-2640. TVB-2640 has shown significant efficacy in high-grade RCC with low KAT2B expression. Example 1: 1. Methods for validating the function of FASN inhibitors (1) Viability assay of 2D cultured RCC renal cell carcinoma cell lines 5000 RCC cells were seeded in 96-well plates and treated with different concentrations of FASN inhibitors for 48 hours. Cell viability was assessed using the CCK8 assay. Figure 2 It can be seen that in the VHL wild-type RCC cell line, the inhibitor TVB-2640 is more sensitive to Caki-1 cells with low KAT2B expression. From Figure 3It can be seen that in the VHL mutant RCC cell line, the inhibitor TVB-2640 is more sensitive to 769P cells with low KAT2B expression.

[0025] (2) Viability experiment of 3D cultured RCC cell lines A 3D culture model of RCC cell lines was constructed. Fifteen organoids were randomly selected from each group for statistical analysis. Representative images of Caki-1, ACHN, 786O, and 769P 3D cultures after treatment with TVB-2640 (7.5 μM) are shown below. Figure 6 As shown. From Figure 6 and Figure 7 It is evident that the inhibitor TVB-2640 is more effective in treating Caki-1 and 769P with low KAT2B expression.

[0026] (3) Primary RCC cell viability assay Primary renal cell carcinoma (RCC) cells were extracted from fresh clinical renal cell carcinoma tissue, and their viability after treatment with TVB-2640 was detected. The statistical analysis of cell viability is shown in the figure below. Figure 4 KAT2B protein expression was then detected in RCC tissues extracted from three independent sites. The KAT2B protein expression diagram is shown below. Figure 5 As shown. From Figure 4 and Figure 5 It can be seen that the inhibitor TVB-2640 has a poor tumor-suppressing effect on primary RCC cells with non-low KAT2B expression, while the inhibitor TVB-2640 has a better tumor-suppressing effect on RCC cells with low KAT2B expression.

[0027] (4) RCC organoid viability experiment In establishing a patient-derived organoid (PDO) model, the inhibitor TVB-2640 showed poor tumor-suppressive effects against RCC organoids with non-low KAT2B expression. Figure 8 , Figure 9 and Figure 10 It can be seen that the inhibitor TVB-2640 has a good tumor-suppressing effect on RCC organoids with low KAT2B expression.

[0028] (5) KAT2B expression inconsistent in RCC cell lines under the same genetic background. KAT2B expression was stably knocked down in ACHN and primary RCC cells using shRNA. The inhibitor TVB-2640, prior to KAT2B knockdown, showed poor inhibitory effects on ACHN and primary RCC cells, while the inhibitor TVB-2640, after KAT2B knockdown, showed good inhibitory effects on both ACHN and primary RCC cells.

[0029] (6) In vivo model A human kidney cell line xenograft model was established using nude mice. The inhibitor TVB-2640 significantly inhibited the growth of 786O cells with stable KAT2B knockdown.

[0030] The statistical graphs of cell viability of ACHN and Caki-1 cells after TVB-2640 treatment are shown below. Figure 2 As shown in the figure, the cell viability statistics of 786O and 769P cells after treatment with TVB-2640 are shown in the figure. Figure 3 As shown in the figure, the viability statistics of primary RCC cells after TVB-2640 treatment are shown in the figure. Figure 4 As shown in the figure, the expression of KAT2B protein in RCC tissues extracted from three independent sites is shown in the figure. Figure 5 As shown, representative images of Caki-1 and ACHN 3D cultures treated with TVB-2640 (7.5 μM) are shown below. Figure 6 As shown, representative images of Caki-1 and ACHN 3D cultures treated with TVB-2640 (7.5 μM) are shown below. Figure 7 As shown, representative images of two PDOs with different KAT2B expression levels after TVB-2640 processing are shown in the figure. Figure 8 As shown, representative images and statistical graphs of PRO-1 staining in PDO are shown below. Figure 9 and Figure 10 As shown (positive staining occurs during organoid apoptosis or death), the statistical graph of cell viability of ACHN cells after KAT2B knockdown and treatment with TVB-2640 is shown. Figure 11 As shown in the figure, the cell viability statistics of primary RCC cells from patient 1 after KAT2B knockdown and treatment with TVB-2640 are shown in the figure. Figure 12 As shown, images of subcutaneous xenografts formed from KAT2B knockdown 786O cells treated with TVB-2640 are presented. Figure 13 As shown in the figure, the tumor growth curve of subcutaneous xenografts formed by KAT2B knockdown 786O cells treated with TVB-2640 is shown in the figure. Figure 14 As shown.

[0031] Figures 15 to 17 The results showed that the growth of HK-2, ACHN, OSRC-2, 786O, A498, 769P and Caki-1 cells was inhibited with increasing TVB-2640 concentration, and the effect was positively correlated.

[0032] Conclusions: Cell viability assays in 2D and 3D cell viability studies showed that the inhibitor TVB-2640 was more sensitive to Caki-1 and 769P cells with low KAT2B expression. Primary RCC cell and organoid assays showed that the inhibitor TVB-2640 was more sensitive to primary RCC cells and organoids with low KAT2B expression, and exhibited good tumor-suppressive activity in RCC cells. Patient-derived organoid (PDO) models showed that the inhibitor TVB-2640 significantly inhibited tissue growth in low KAT2B-expressing tissues, and cell death staining yielded consistent results. ACHN cell and primary cell models showed that knocking down KAT2B enhanced the inhibitory effect of the inhibitor TVB-2640 on ACHN cells and primary cells.

[0033] In vivo models showed that the inhibitor TVB-2640 significantly inhibited the growth of KAT2B knockdown 786O cells. KAT2B is also lowly expressed in lung adenocarcinoma and breast cancer, and the inhibitor TVB-2640 was equally effective in these tumors with low KAT2B expression, suggesting that this drug can be used for a wider range of tumors with low KAT2B expression.

[0034] 2. Methods for verifying the mechanism of FASN inhibitors (1) Perform gene set enrichment analysis (GSEA) of the TCGA-KIRC project, Caki-1 cell model overexpressing KAT2B, xenograft tumor model, fatty acid uptake experiment, and lipid droplet degradation kinetics study.

[0035] Conclusion: Gene set enrichment analysis (GSEA) of the TCGA-KIRC project showed that KAT2B is associated with adipocyte differentiation and lipid metabolism.

[0036] In the Caki-1 cell group overexpressing KAT2B, lipidomics analysis was performed using liquid chromatography-mass spectrometry (LC / MS) to analyze both the cells and normal cells. Principal component analysis (PCA) revealed significant differences in lipid metabolism between the two groups. The results showed that 153 lipid metabolites were downregulated and 44 were upregulated in KAT2B-overexpressing cells. After raising the screening criteria, 84 lipid metabolites, mainly glycerides, phospholipids, sphingolipids, and fatty acids, were confirmed to be downregulated. These metabolites are mostly major components of lipid droplets. Figure 18 As shown, Oil Red O staining revealed a significant reduction in lipid droplets in RCC cells due to KAT2B overexpression. Triglyceride and cholesterol ester detection results also indicated that KAT2B primarily inhibited triglyceride levels. In a xenograft tumor model, knockdown of KAT2B significantly increased lipid droplet accumulation in a mouse spontaneous renal tumor model.

[0037] Factors influencing lipid droplet levels include fatty acid uptake, lipidogenesis, and lipid degradation. Fatty acid uptake experiments showed that KAT2B had no significant effect on fatty acid uptake. Lipid droplet degradation kinetics studies showed that KAT2B did not promote lipid droplet degradation. Finally, KAT2B was found to significantly inhibit lipidogenesis. Lipidogenesis involves eight key enzymes and two transcription factors; through functional screening experiments, it was ultimately discovered that KAT2B exerts its inhibitory effect on lipid synthesis through FASN.

[0038] In summary, high expression of KAT2B inhibits lipid regeneration.

[0039] (2) Establish a 786O cell model with KAT2B knockdown To establish a 786O cell model with KAT2B knockdown, we first constructed an shRNA targeting the KAT2B gene to knock down KAT2B in 786O cells, thus inhibiting KAT2B expression. Significant lipid accumulation was observed after KAT2B knockdown, indicating that low expression of KAT2B promotes cellular lipid accumulation.

[0040] (3) Silencing FASN in the 786O cell model with knockdown of KAT2B Based on the 786O cell model with KAT2B knockdown, FASN was silenced. It was found that silencing FASN alone could significantly reverse lipid accumulation caused by KAT2B knockdown, suggesting that KAT2B exerts its effect by regulating FASN, and inhibiting FASN can reverse abnormal lipid accumulation caused by cells with low KAT2B expression.

[0041] 3. Verification method for the specific mechanism of KAT2B regulating FASN (1) Construction of acetyltransferase inactivation mutant KAT2B Acetyltransferase inactivation failed to inhibit FASN expression. Treatment of KAT2B-overexpressing cells with the histone deacetylation agonist ITSA-1 did not restore FASN expression, indicating that KAT2B functions independently of histone acetylation. Co-immunoprecipitation (Co-IP) and LC-MS analysis identified 335 proteins interacting with KAT2B, with HDAC5 being the most prominent among lipid metabolism-related proteins. HDAC5 was associated with both KAT2B and FASN expression.

[0042] (2) Cell experiments Functional salvage assays confirmed that HDAC5 is a key mediator of KAT2B's inhibition of lipid accumulation and tumor progression. Endogenous interaction between KAT2B and HDAC5 was verified in A498 cells with high KAT2B expression and Caki-1 cells with low KAT2B expression, while exogenous interaction was also verified in 293T cells. Subsequently, a truncated KAT2B mutant was constructed, revealing that its N-acetyltransferase domain is the key region for HDAC5 binding. This indicates that KAT2B does not affect HDAC5 expression levels but significantly increases its acetylation levels.

[0043] Acetylmics analysis revealed a significant increase in acetylation at the K726 site of HDAC5 upon KAT2B overexpression, while acetyltransferase-inactivated KAT2B showed no such effect. Cross-species sequence analysis showed that K726 was highly conserved. Mutating HDAC5's K726 to arginine (K726R) blocked its acetylation. In vitro acetylation experiments further confirmed that KAT2B acetylates HDAC5 at the K726 site. Immunofluorescence and cell component separation experiments indicated that KAT2B promotes HDAC5 extranuclear transport through its acetyltransferase activity.

[0044] HDAC5 contains nuclear localization signals (NLS) and nuclear export signals (NES). The K726 site is close to the NES, suggesting that its acetylation may promote NES exposure. Co-IP analysis showed that HDAC5 specifically binds to the nuclear export receptor Exportin1. KAT2B promotes the binding of HDAC5 to Exportin1, while the K726R mutation disrupts this effect. Immunofluorescence showed that deletion of the HDAC5 NES sequence or the K726R mutation reversed KAT2B-induced extranuclear transport of HDAC5.

[0045] HDAC5 is known to form a nuclear complex with LSD1, stabilizing LSD1, while LSD1 promotes FASN expression by reducing histone methylation. KAT2B overexpression significantly reduces LSD1 protein levels and decreases the formation of the HDAC5 / LSD1 complex. An acetylation-mimicking mutation (K726Q) in HDAC5K726 enhances complex formation, while a non-acetylation mutation (K726R) weakens it. The exportin1 inhibitor Eltanexor restores LSD1 expression, indicating that HDAC5 nuclear export has a significant impact on LSD1 stability.

[0046] Overexpression experiments using wild-type and mutant KAT2B and HDAC5 confirmed that KAT2B function depends on acetylation at the HDAC5K726 site. Functional salvage experiments further confirmed that KAT2B's tumor-suppressive effect depends on its ability to acetylate HDAC5 and disrupt the HDAC5 / LSD1 complex.

[0047] Treatment with cyclohexylimide (CHX) showed that KAT2B accelerated LSD1 protein degradation, while MG132 (a proteasome inhibitor) and nonchloroquine (a lysosomal inhibitor) blocked LSD1 degradation. Western blotting results showed that KAT2B overexpression increased LSD1 ubiquitination levels. Therefore, KAT2B promotes nuclear export of HDAC5 through acetylation, disrupts its complex with LSD1, thereby inducing LSD1 ubiquitination and degradation, and ultimately inhibiting FASN transcriptional activity.

[0048] Furthermore, KAT2B regulates FASN expression through LSD1-mediated H3K9 methylation. Inhibition of H3K9 methylation using chaetocin partially reverses the inhibitory effect of KAT2B on FASN.

[0049] (3) In vivo experiments To further validate the in vivo effects of the aforementioned mechanisms, a Caki-1 cell xenograft model overexpressing KAT2B and / or HDAC5 was constructed. Consistent with in vitro experiments, HDAC5 overexpression reversed the inhibitory effect of KAT2B on tumor proliferation. Immunoblotting and immunohistochemical analyses showed that HDAC5 reversed the inhibition of FASN by KAT2B through stabilizing LSD1 expression. Ki6 staining also supported this conclusion. Oil Red O staining results indicated that HDAC5 could reverse KAT2B-mediated lipid reduction.

[0050] The tail vein injection transfer model further validated that HDAC5 could reverse the inhibitory effect of KAT2B on RCC metastasis. In summary, the KAT2B / HDAC5 / LSD1 / FASN axis can inhibit RCC lipid production and progression in vivo.

[0051] 4. Validation of KAT2B in lipid metabolism-related biomarkers (1) Verify the key role of abnormal lipid metabolism in RCC To assess and validate the crucial role of abnormal lipid metabolism in renal cell carcinoma (RCC), transcriptome sequencing was performed on three pairs of human RCC and adjacent normal tissues. Enrichment analysis of differentially expressed genes and Oil Red O staining revealed significant lipid metabolism abnormalities in RCC. Subsequently, a spontaneous renal tumor model was established by injecting AKT and MYC plasmids into mouse kidneys. High expression of the RCC marker CAIX indicated a high similarity between this model and RCC. Oil Red O staining showed significant lipid accumulation in renal tumor tissue compared to normal kidney tissue.

[0052] (2) Screening for key genes that may lead to lipid accumulation in RCC Oil Red O staining and triglyceride analysis were performed on six RCC cell lines. Caki-1, 769P, and A498 cells showed the most significant lipid accumulation. Differential gene analysis was performed between high-lipid-content and low-lipid-content cell lines, identifying 1374 differentially expressed genes associated with lipid metabolism in RCC. Further intersection analysis with two lipid metabolism-related datasets and one RCC progression-related dataset revealed three potential key genes. Comparison of the expression levels of these three genes using the TCGA database identified the KAT2B gene as the most promising.

[0053] (3) Verify that low expression of KAT2B is associated with late-stage RCC. Further validation in the RCC cohort and TCGA database revealed that KAT2B was significantly downregulated in RCC, especially in advanced RCC tissues. ROC curve and Kaplan-Meier curve analyses indicated that KAT2B has good diagnostic and prognostic value. Further univariate and multivariate analyses confirmed that KAT2B is an independent prognostic factor for RCC. Compared with normal renal epithelial tissue, KAT2B expression was significantly reduced in RCC cells, a finding also validated in cell lines.

[0054] The expression levels of KAT2B and FASN in 23 late-stage RCC samples and the correlation scatter plot of their content are shown below. Figure 19 As shown, KAT2B expression is negatively correlated with FASN expression in advanced renal cell carcinoma.

[0055] (4) Verify that high expression of KAT2B inhibits the proliferation of RCC cells. To eliminate the influence of VHL mutations, functional experiments were performed using the VHL wild-type ACHN and Caki-1 cell lines, and the VHL mutant 786O and A498 cell lines. KAT2B was stably overexpressed in A498 and Caki-1 cells using lentivirus, while KAT2B was knocked down in ACHN and 786O cells. Figure 20 As shown, CCK-8 assays indicate that KAT2B can inhibit RCC cell proliferation; as Figure 21 As shown, the results of the clone formation experiment also support this conclusion.

[0056] Transwell assays showed that KAT2B significantly inhibited the migration and invasion of RCC cells. A xenograft tumor model was established by seeding KAT2B-overexpressing Caki-1 cells into the axillae of nude mice. Figure 22 The results showed that KAT2B inhibited tumor growth, such as Figure 23 Immunohistochemical staining of the tumor showed a significant decrease in Ki67 in the KAT2B overexpression group. Figure 24 and Figure 25The results showed that when Caki-1 cells were injected into the tail vein to establish an RCC metastasis model, both in vivo imaging of small animals and HE staining of liver tissue showed that KAT2B overexpression significantly inhibited tumor metastasis.

[0057] It is evident that RCC cells can enhance lipid synthesis by downregulating KAT2B expression. This not only provides the necessary lipids for cell membrane synthesis but also meets the needs for energy storage and signal transduction, thereby promoting tumor growth and survival.

[0058] According to Example 1: (1) In tumors with low KAT2B expression, FASN expression is increased, and they are more sensitive to FASN inhibitors. FASN inhibitors are expected to be potential drugs for treating RCC or other tumors with low KAT2B expression, correcting abnormal lipid accumulation, effectively inhibiting RCC progression, and enhancing sensitivity to sunitinib. The inhibitor TVB-2640, whether used as a monotherapy or in combination with TKIs and immune checkpoint inhibitors, lays the foundation for its clinical application in RCC patients; (2) KAT2B and FASN inhibit each other and are both significantly associated with lipid accumulation in cells. High expression of KAT2B inhibits lipid regeneration, low expression of KAT2B promotes lipid accumulation in cells, FASN promotes lipid accumulation in cells, and inhibiting FASN can reverse abnormal lipid accumulation caused by low KAT2B expression cells. (3) The KAT2B / HDAC5 / LSD1 / FASN axis is expected to be used as a new therapeutic target axis for RCC in the preparation of drugs for treating RCC. Such drugs can inhibit lipid production and progression of RCC in vivo by disrupting the KAT2B / HDAC5 / LSD1 / FASN axis.

[0059] (4) KAT2B is a key gene for abnormal lipid metabolism in RCC. KAT2B is significantly downregulated in RCC, especially in late-stage RCC tissues. KAT2B has good diagnostic and prognostic value for RCC. High expression of KAT2B can inhibit the proliferation of RCC cells.

[0060] Based on the above, the present invention further discloses the application of KAT2B products in the preparation of products for screening or treating renal cell carcinoma. KAT2B as a product can be a KAT2B agonist or stabilizer, or a small molecule drug or virus that promotes KAT2B expression or a drug carrying KAT2B mRNA.

[0061] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. Application of FASN inhibitors in the preparation of drugs for treating renal cell carcinoma with low KAT2B expression.

2. The application according to claim 1, characterized in that, The FASN inhibitor is used to inhibit abnormal lipid accumulation in cells or tissues with low KAT2B expression.

3. The application according to claim 1, characterized in that, The FASN inhibitor is the inhibitor TVB-2640.

4. Application of KAT2B products in the preparation of products for screening or treating clear cell renal cell carcinoma.

5. The application according to claim 4, characterized in that, KAT2B overexpression inhibits abnormal lipid accumulation in clear cell renal cell carcinoma, while KAT2B underexpression promotes abnormal lipid accumulation in clear cell renal cell carcinoma.

6. The application of KAT2B-targeted products in the preparation of products for screening or treating clear cell renal cell carcinoma, characterized in that... The target of KAT2B is FASN, which promotes abnormal lipid accumulation in clear cell renal cell carcinoma. Inhibiting FASN can reverse the abnormal lipid accumulation caused by cells with low KAT2B expression.

7. The application according to claim 6, characterized in that, This includes the application of the KAT2B / HDAC5 / LSD1 / FASN axis in the preparation of products for the treatment of clear cell renal cell carcinoma; Specifically, KAT2B acetylates the K726 site of HDAC5, enhancing the binding of the K726 site to Exportin1 and promoting its extranuclear transport, thereby disrupting the assembly of the nuclear HDAC5-LSD1 complex, promoting histone methylation, and inhibiting FASN expression.

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