KAT6A amplifications are associated with shorter progression-free survival and overall survival in patients with endometrial serous carcinoma

Identification of triazolyl KAT6 inhibitors via a templated fragment approach

KAT6, a histone acetyltransferase from the MYST family, has emerged as an attractive oncology target due to its role in regulating genes that control cell cycle progression and cellular senescence. Amplification of the KAT6A gene has been seen among patients with worse clinical outcome in ER+ breast cancers. Although multiple inhibitors have been reported, no KAT6 inhibitors have been approved to date. Here, we report the fragment-based discovery of a series of N-(1-phenyl-1H-1,2,3-triazol-4-yl)benzenesulfonamide KAT6 inhibitors and early hit-to-lead efforts to improve the KAT6 potency.

ERα status of invasive ductal breast carcinoma as a result of regulatory interactions between lysine deacetylases KAT6A and KAT6B

Breast cancer (BC) is the leading cause of death among cancer patients worldwide. In 2020, almost 12% of all cancers were diagnosed with BC. Therefore, it is important to search for new potential markers of cancer progression that could be helpful in cancer diagnostics and successful anti-cancer therapies. In this study, we investigated the potential role of the lysine acetyltransferases KAT6A and KAT6B in the outcome of patients with invasive breast carcinoma. The expression profiles of KAT6A/B in 495 cases of IDC and 38 cases of mastopathy (FBD) were examined by immunohistochemistry. KAT6A/B expression was also determined in the breast cancer cell lines MCF-7, BT-474, SK-BR-3, T47D, MDA-MB-231, and MDA-MB-231/BO2, as well as in the human epithelial mammary gland cell line hTERT-HME1 - ME16C, both at the mRNA and protein level. Statistical analysis of the results showed that the nuclear expression of KAT6A/B correlates with the estrogen receptor status: KAT6ANUC vs. ER r = 0.2373 and KAT6BNUC vs. ER r = 0.1496. Statistical analysis clearly showed that KAT6A cytoplasmic and nuclear expression levels were significantly higher in IDC samples than in FBD samples (IRS 5.297 ± 2.884 vs. 2.004 ± 1.072, p < 0.0001; IRS 5.133 ± 4.221 vs. 0.1665 ± 0.4024, p < 0.0001, respectively). Moreover, we noticed strong correlations between ER and PR status and the nuclear expression of KAT6A and KAT6B (nucKAT6A vs. ER, p = 0.0048; nucKAT6A vs. PR p = 0.0416; nucKAT6B vs. ER p = 0.0306; nucKAT6B vs. PR p = 0.0213). Significantly higher KAT6A and KAT6B expression was found in the ER-positive cell lines T-47D and BT-474, whereas significantly lower expression was observed in the triple-negative cell lines MDA-MB-231 and MDA-MB-231/BO2. The outcomes of small interfering RNA (siRNA)-mediated suppression of KAT6A/B genes revealed that within estrogen receptor (ER) positive and negative cell lines, MCF-7 and MDA-MB-231, attenuation of KAT6A led to concurrent attenuation of KAT6A, whereas suppression of KAT6B resulted in simultaneous attenuation of KAT6A. Furthermore, inhibition of KAT6A/B genes resulted in a reduction in estrogen receptor (ER) mRNA and protein expression levels in MCF-7 and MDA-MMB-231 cell lines. Based on our findings, the lysine acetyltransferases KAT6A and KAT6B may be involved in the progression of invasive ductal breast cancer. Further research on other types of cancer may show that KAT6A and KAT6B could serve as diagnostic and prognostic markers for these types of malignancies.

Prognostic analysis of patients with gastric cancer based on N6-methyladenosine modification patterns and tumor microenvironment characterization

Background

Cancers arise from genetic and epigenetic abnormalities that affect oncogenes and tumor suppressor genes, compounded by gene mutations. The N6-methyladenosine (m6A) RNA modification, regulated by methylation regulators, has been implicated in tumor proliferation, differentiation, tumorigenesis, invasion, and metastasis. However, the role of m6A modification patterns in the tumor microenvironment of gastric cancer (GC) remains poorly understood.

Materials and methods

In this study, we analyzed m6A modification patterns in 267 GC samples utilizing 31 m6A regulators. Using consensus clustering, we identified two unique subgroups of GC. Patients with GC were segregated into high- and low-infiltration cohorts to evaluate the infiltration proportions of the five prognostically significant immune cell types. Leveraging the differential genes in GC, we identified a "green" module via Weighted Gene Co-expression Network Analysis. A risk prediction model was established using the LASSO regression method.

Results

The "green" module was connected to both the m6A RNA methylation cluster and immune infiltration patterns. Based on "Module Membership" and "Gene Significance", 37 hub genes were identified, and a risk prediction model incorporating nine hub genes was established. Furthermore, methylated RNA immunoprecipitation and RNA Immunoprecipitation assays revealed that YTHDF1 elevated the expression of DNMT3B, which synergistically promoted the initiation and development of GC. We elucidated the molecular mechanism underlying the regulation of DNMT3B by YTHDF1 and explored the crosstalk between m6A and 5mC modification.

Conclusion

m6A RNA methylation regulators are instrumental in malignant progression and the dynamics of tumor microenvironment infiltration of GC. Assessing m6A modification patterns and tumor microenvironment infiltration characteristics in patients with GC holds promise as a valuable prognostic biomarker.

Pharmacological targeting of the cancer epigenome

Epigenetic dysregulation is increasingly appreciated as a hallmark of cancer, including disease initiation, maintenance and therapy resistance. As a result, there have been advances in the development and evaluation of epigenetic therapies for cancer, revealing substantial promise but also challenges. Three epigenetic inhibitor classes are approved in the USA, and many more are currently undergoing clinical investigation. In this Review, we discuss recent developments for each epigenetic drug class and their implications for therapy, as well as highlight new insights into the role of epigenetics in cancer.

Recurrent Somatic Copy Number Alterations and Their Association with Oncogene Expression Levels in High-Grade Ovarian Serous Carcinoma

Somatic copy number alterations (SCNAs) are frequently observed in high-grade ovarian serous carcinoma (HGOSC). However, their impact on gene expression levels has not been systematically assessed. In this study, we explored the relationship between recurrent SCNA and gene expression using The Cancer Genome Atlas Pan Cancer dataset (OSC, TCGA, PanCancer Atlas) to identify cancer-related genes in HGOSC. We then investigated any association between highly correlated cancer genes and clinicopathological parameters, including age of diagnosis, disease stage, overall survival (OS), and progression-free survival (PFS). A total of 772 genes with recurrent SCNAs were observed. SCNA and mRNA expression levels were highly correlated for 274 genes; 24 genes were classified as a Tier 1 gene in the Cancer Gene Census in the Catalogue of Somatic Mutations in Cancer (CGC-COSMIC). Of these, 11 Tier 1 genes had highly correlated SCNA and mRNA expression levels: TBL1XR1, PIK3CA, UBR5, EIF3E, RAD21, EXT1, RECQL4, KRAS, PRKACA, BRD4, and TPM4. There was no association between gene amplification and disease stage or PFS. EIF3E, RAD21, and EXT1 were more frequently amplified in younger patients, specifically those under the age of 55 years. Patients with tumors carrying PRKACA, BRD4, or TPM4 amplification were associated with a significantly shorter OS. RECQL4 amplification was more frequent in younger patients, and tumors with this amplification were associated with a significantly better OS.

In Silico Study on the Interactions, Molecular Docking, Dynamics and Simulation of Potential Compounds from Withania somnifera (L.) Dunal Root against Cancer by Targeting KAT6A

Cancer is characterized by the abnormal development of cells that divide in an uncontrolled manner and further take over the body and destroy the normal cells of the body. Although several therapies are practiced, the demand and need for new therapeutic agents are ever-increasing because of issues with the safety, efficacy and efficiency of old drugs. Several plant-based therapeutics are being used for treatment, either as conjugates with existing drugs or as standalone formulations. Withania somnifera (L.) Dunal is a highly studied medicinal plant which is known to possess immunomodulatory activity as well as anticancer properties. The pivotal role of KAT6A in major cellular pathways and its oncogenic nature make it an important target in cancer treatment. Based on the literature and curated datasets, twenty-six compounds from the root of W. somnifera and a standard inhibitor were docked with the target KAT6A using Autodock vina. The compounds and the inhibitor complexes were subjected to molecular dynamics simulation (50 ns) using Desmond to understand the stability and interactions. The top compounds (based on the docking score of less than -8.5 kcal/mol) were evaluated in comparison to the inhibitor. Based on interactions at ARG655, LEU686, GLN760, ARG660, LEU689 and LYS763 amino acids with the inhibitor WM-8014, the compounds from W. somnifera were evaluated. Withanolide D, Withasomniferol C, Withanolide E, 27-Hydroxywithanone, Withanolide G, Withasomniferol B and Sitoindoside IX showed high stability with the residues of interest. The cell viability of human breast cancer MCF-7 cells was evaluated by treating them with W. Somnifera root extract using an MTT assay, which showed inhibitory activity with an IC50 value of 45 µg/mL. The data from the study support the traditional practice of W. somnifera as an anticancer herb.

circUBAP2 inhibits cisplatin resistance in gastric cancer via miR-300/KAT6B axis

Circular RNAs play an important role in regulating cisplatin (CDDP) resistance in gastric cancer (GC). The aim of this study was to examine the role and downstream regulation mechanisms of circUBAP2 in CDDP resistance of GC. The expression of circUBAP2 in GC and its correlation with the prognosis of GC patients were analyzed using qRT-PCR and the Kaplan-Meier plotter database. The effects of circUBAP2 on cell viability and apoptosis were investigated by Cell Counting Kit 8 assay and flow cytometry. The expressions of drug-resistance-related proteins, P-gp and MRP1, were detected by Western blot. The interaction between circUBAP2 and miR-300 was confirmed using RNA pulldown and immunoprecipitation assays. The correlation between miR-300 and KAT6B was assessed using dual-luciferase reporter assay and TCGA database. CircUBAP2 was downregulated in GC tissues and cell lines, and correlated with the poor prognosis of GC. In addition, circUBAP2 enhanced apoptosis but inhibited cell viability and the CDDP resistance of GC cells in vitro . CircUBAP2 acted as a sponge of microRNA-300 (miR-300) and was negatively correlated with miR-300. Moreover, the upregulation of miR-300 partially removed the effects of circUBAP2 on cell viability, apoptosis and CDDP resistance in GC cells. MiR-300 directly targeted to lysine acetyltransferase 6B (KAT6B), and KAT6B overexpression showed an inhibitory effect on cell viability and CDDP resistance of GC cells. Our data suggested that the circUBAP2/miR-300/KAT6B axis was involved in the inhibition of CDDP resistance in GC, which might provide a novel focus for potential GC therapy.

miR-339-3p inhibits cell growth and epithelial-mesenchymal transition in nasopharyngeal carcinoma by modulating the KAT6A/TRIM24 axis

OBJECTIVE

To explore the effect and mechanism of the miR-339-3p/KAT6A/TRIM24 axis in nasopharyngeal carcinoma (NPC) cell growth and epithelial-mesenchymal transition (EMT) progression.

METHODS

CNE2 and 5-8F NPC cell lines were transfected with miR-339-3p-mimic or sh-KAT6A alone or co-transfected with miR-339-3p-mimic and oe-KAT6A. The expression levels of miR-339-3p, KAT6A, TRIM24, and EMT-related proteins were assessed, in addition to cell biological behaviors. Then, the relationship between miR-339-3p and KAT6A was predicted and validated. The correlations between miR-339-3p and KAT6A or between KAT6A and TRIM24 were analyzed by Pearson coefficient and the enrichment of H3K23ac in TRIM24 promoter region was measured by chromatin immunoprecipitation.

RESULTS

miR-339-3p was downregulated, but KAT6A and TRIM24 were highly expressed in NPC cells and tissues. Upregulated miR-339-3p or downregulated KAT6A could inhibit the growth and EMT of NPC cells. Further experiments showed that miR-339-3p regulated NPC cell growth and EMT by mediating KAT6A in a targeted fashion. KAT6A was positively correlated with TRIM24, and the enrichment of H3K23ac was much higher in NPC tissues. miR-339-3p suppressed the growth and EMT of NPC cells by the KAT6A/TRIM24 axis. In a xenograft study, miR-339-3p overexpression inhibited NPC tumor growth in vivo.

CONCLUSION

Conclusively, miR-339-3p inhibited the growth and EMT of NPC cells via the KAT6A/TRIM24 axis.

Matrix stiffness-induced upregulation of histone acetyltransferase KAT6A promotes hepatocellular carcinoma progression through regulating SOX2 expression

BACKGROUND

Lysine acetyltransferase 6 A (KAT6A) is a MYST-type histone acetyltransferase (HAT) enzyme, which contributes to histone modification and cancer development. However, its biological functions and molecular mechanisms, which respect to hepatocellular carcinoma (HCC), are still largely unknown.

METHODS

Immunohistochemical, western blot and qRT-PCR analysis of KAT6A were performed. A series of in vitro and in vivo experiments were conducted to reveal the role of KAT6A in the progression of HCC.

RESULTS

We demonstrated that KAT6A expression was upregulated in HCC tissues and cell lines. Clinical analysis showed that increased KAT6A was significantly associated with malignant prognostic features and shorter survival. Gain- and loss-of-function experiments indicated that KAT6A promoted cell viability, proliferation and colony formation of HCC cells in vitro and in vivo. We confirmed that KAT6A acetylates lysine 23 of histone H3 (H3K23), and then enhances the association of the nuclear receptor binding protein TRIM24 and H3K23ac. Consequently, TRIM24 functions as a transcriptional activator to activate SOX2 transcription and expression, leading to HCC tumorigenesis. Restoration of SOX2 at least partially abolished the biological effects of KAT6A on HCC cells. Overexpression of KAT6A acetyltransferase activity-deficient mutants or TRIM24 mutants lacking H3K23ac binding sites did not affect SOX2 expression and HCC biological function. Moreover, matrix stiffness can upregulate the expression of KAT6A in HCC cells.

CONCLUSIONS

Our data support the first evidence that KAT6A plays an oncogenic role in HCC through H3K23ac/TRIM24-SOX2 pathway, and represents a promising therapeutic strategy for HCC patients.

PLK3 amplification and tumor immune microenvironment of metastatic tumors are linked to adjuvant treatment outcomes in uterine serous cancer

Uterine serous carcinoma (USC), an aggressive variant of endometrial cancer representing approximately 10% of endometrial cancer diagnoses, accounts for ∼39% of endometrial cancer-related deaths. We examined the role of genomic alterations in advanced-stage USC associated with outcome using paired primary-metastatic tumors (n = 29) treated with adjuvant platinum and taxane chemotherapy. Comparative genomic analysis of paired primary-metastatic patient tumors included whole exome sequencing and targeted gene expression. Both PLK3 amplification and the tumor immune microenvironment (TIME) in metastatic tumors were linked to time-to-recurrence (TTR) risk without any such association observed with primary tumors. TP53 loss was significantly more frequent in metastatic tumors of platinum-resistant versus platinum-sensitive patients and was also associated with increased recurrence and mortality risk. Increased levels of chr1 breakpoints in USC metastatic versus primary tumors co-occur with PLK3 amplification. PLK3 and the TIME are potential targets for improving outcomes in USC adjuvant therapy.

Expression of epigenetic pathway related genes in association with PD-L1, ER/PgR and MLH1 in endometrial carcinoma

The distribution of Endometrial Cancer (EC)-related deaths is uneven among the morphologic subtypes of EC. Serous Cancer (SC) makes 10% of all EC and accounts for 40% of EC-related deaths. We investigated expression of selected genes involved in epigenetic pathways by immunohistochemistry in a cohort of 106 EC patients and analyzed mRNA-based expression levels for the same set of genes in EC samples from The Cancer Genome Atlas (TCGA) dataset. A tissue microarray was constructed using low-grade (n = 30) and high-grade (n = 28) endometrioid, serous (n = 31) and clear cell carcinoma (n = 17) samples. Epigenetic marker levels were associated with PD-L1, ER/PgR, and MLH1 expression. Epigenetic markers were evaluated by H-score and PD-L1 expression was recorded by using Combined Positive Score. Results were correlated with disease stage and survival outcome. BRD4, KAT6a and HDAC9 levels were higher in SC compared to other histologic subtypes (p<0.001–0.038). After adjusting for multiple comparisons, DNMT3b expression was higher in SC compared to endometrioid-type but not between SC and CCC. The expression levels of BRD4 (p = 0.021) and KAT6a (p = 0.0027) were positively associated with PD-L abundance, while PgR (p = 0.029) and PD-L1 expression were negatively associated. In addition, BRD4 expression was low in specimens with loss of MLH1 expression (p = 0.02). More importantly, BRD4 abundance had a negative impact on disease outcome (p = 0.02). Transcriptionally, BRD4, KAT6a and DNMT3b expression levels were higher in SC in TCGA dataset. The median PD-L1 expression was marginally associated with BRD4, a transcriptional activator of CD274/PD-L1 (p = 0.069) and positively with KAT6a (p = 0.0095). In conclusion, the protein expression levels of epigenetic markers involved in cancer pathogenesis are increased by immunohistochemistry in SC. PD-L1 levels are associated with BRD4 and KAT6a in EC samples. A combination therapy with BRD4/PD-L1 or KAT6a/PD-L1 inhibitors might have a potential use in EC, in particular serous-type carcinoma.

Expression of Enhancer-Binding Protein CEBPA mRNA and Protein in Ovarian Cancer and Its Relationship With Pathobiological Characteristics

Ovarian cancer is a common malignant tumor, its early onset is hidden, lack of specific symptoms, the location of the lesion is particularly hidden, which makes it difficult to find ovarian lesions by general detection, making it difficult to make an early clinical diagnosis. Therefore, it is still the focus and difficulty of ovarian cancer research to find the means of early diagnosis and prognosis of ovarian cancer. Cytosine-cytosine-adenosine-adenosine-thymidine (CCAAT) enhancer-binding protein α (CEBPA) has been proved to be involved in cell metabolism, proliferation, and differentiation. In this study, the expression of CEBPA mRNA and protein in normal ovary, epithelial ovarian cyst, ovarian borderline tumor, and ovarian cancer was detected, the relationship between CEBPA and pathobiological characteristics of ovarian cancer was discussed, and its influence on the prognosis of patients with ovarian cancer was analyzed. The results showed that the expression of CEBPA mRNA and protein in patients with ovarian borderline tumor and ovarian cancer is high, and the expression of CEBPA has no obvious correlation with the pathobiological characteristics of patients with ovarian cancer, and the high expression of CEBPA has an important value in the diagnosis of ovarian cancer, and it is also a poor prognostic factor of the disease.

KAT6A is associated with sorafenib resistance and contributes to progression of hepatocellular carcinoma by targeting YAP

Hepatocellular carcinoma (HCC) is a prevalent solid cancer worldwide and sorafenib is a common treatment. Nevertheless, sorafenib resistance is a severe clinical problem. In the present study, we identified that epigenetic regulator, KAT6A, was overexpressed in clinical HCC tissues and sorafenib-resistant HCC samples. The depletion of KAT6A repressed the cell viability and Edu-positive cell numbers of HCC cells. The IC50 value of sorafenib was increased in sorafenib-resistant HCC cells. In addition, the expression of KAT6A was induced in sorafenib-resistant HCC cells. The depletion of KAT6A suppressed the IC50 of sorafenib. Mechanically, YAP was decreased by the depletion of KAT6A. KAT6A was able to enrich in the promoter of YAP. The silencing of KAT6A reduced the enrichment of histone H3 lysine 23 acetylation (H3K23ac) and RNA polymerase II (RNA pol II) on the promoter of YAP in sorafenib-resistant HCC cells. KAT6A inhibitor WM-1119 repressed the cell proliferation of sorafenib-resistant HCC cells, while overexpression of KAT6A or YAP could reverse the effect in the cells. Meanwhile, the treatment of sorafenib inhibited the viability of sorafenib-resistant HCC cells, while the co-treatment of WM-1119 could improve the effect of sorafenib. Collectively, KAT6A was associated with sorafenib resistance and contributes to progression of HCC by targeting YAP. Targeting KAT6A may be served as a promising therapeutic approach for HCC.

KAT6A Acetylation of SMAD3 Regulates Myeloid-Derived Suppressor Cell Recruitment, Metastasis, and Immunotherapy in Triple-Negative Breast Cancer

Aberrant SMAD3 activation has been implicated as a driving event in cancer metastasis, yet the underlying mechanisms are still elusive. Here, SMAD3 is identified as a nonhistone substrate of lysine acetyltransferase 6A (KAT6A). The acetylation of SMAD3 at K20 and K117 by KAT6A promotes SMAD3 association with oncogenic chromatin modifier tripartite motif-containing 24 (TRIM24) and disrupts SMAD3 interaction with tumor suppressor TRIM33. This event in turn promotes KAT6A-acetylated H3K23-mediated recruitment of TRIM24-SMAD3 complex to chromatin and thereby increases SMAD3 activation and immune response-related cytokine expression, leading to enhanced breast cancer stem-like cell stemness, myeloid-derived suppressor cell (MDSC) recruitment, and triple-negative breast cancer (TNBC) metastasis. Inhibiting KAT6A in combination with anti-PD-L1 therapy in treating TNBC xenograft-bearing animals markedly attenuates metastasis and provides a significant survival benefit. Thus, the work presents a KAT6A acetylation-dependent regulatory mechanism governing SMAD3 oncogenic function and provides insight into how targeting an epigenetic factor with immunotherapies enhances the antimetastasis efficacy.