Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) cell line H3K27ac CUT&RUN. Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) cell line H3K27ac CUT&RUN

Small cell carcinoma of the ovary-hypercalcemic type (SCCOHT) is a rare form of ovarian cancer affecting young women and girls. Survival rates remain poor despite aggressive treatment of these patients with high-dose chemotherapy and radiation. SCCOHT is driven by loss of both SWI/SNF ATPases SMARCA4 and SMARCA2. Loss of SWI/SNF complex activity alters chromatin state, particularly at enhancers, which is believed to be crucial for oncogenesis. Super-enhancers are a distinct subset of enhancer clusters frequently associated with oncogenes in cancer. Here we discovered key distinctions between SWI/SNF binding following SMARCA4 restoration at enhancer vs. super-enhancer sites and characterized putative oncogene expression driven by super-enhancer activity. We found high sensitivity of SCCOHT cell lines to triptolide, a small molecule derived from the naturally occurring "thunder god vine" (Tripterygium wilfordii) that targets the XPB subunit of the transcription factor II H (TFIIH) complex, found at super-enhancers. Triptolide inhibits expression of many super-enhancer associated genes, and in particular, oncogenes. Notably, SALL4 expression, which is high in SCCOHT relative to other ovarian cancers and normal cell types, is significantly decreased following short triptolide treatment. In SCCOHT patient-derived xenograft models, triptolide and its prodrug derivative minnelide are particularly effective in inhibiting tumor growth. These results demonstrate the key oncogenic role of super-enhancer activity following epigenetic dysfunction in SCCOHT, which can be effectively targeted through inhibition of its functional components, such as TFIIH inhibition with triptolide. Overall design: BIN67, SCCOHT, and COV434 SCCOHT cell line H3K27ac & IgG CUT&RUN

卵巢高钙血症型小细胞癌（Small cell carcinoma of the ovary-hypercalcemic type, SCCOHT）是一类罕见的卵巢癌亚型，多发于年轻女性与女童。尽管针对此类患者采用大剂量化疗联合放疗的强化治疗方案，其生存率仍不容乐观。SCCOHT的发病由SWI/SNF ATP酶（SWI/SNF ATPases）SMARCA4与SMARCA2的双缺失驱动。SWI/SNF复合物活性丧失会改变染色质状态，尤其是增强子区域的染色质状态，这被认为在肿瘤发生过程中至关重要。超级增强子（super-enhancers）是一类独特的增强子簇亚群，在癌症中常与致癌基因紧密关联。本研究揭示了SMARCA4恢复表达后，SWI/SNF在普通增强子与超级增强子位点的结合差异，并对超级增强子活性驱动的潜在致癌基因表达特征进行了系统表征。研究发现，SCCOHT细胞系对雷公藤甲素（triptolide）具有高度敏感性：该小分子化合物提取自天然来源的「雷公藤」（Tripterygium wilfordii），可靶向结合转录因子IIH（TFIIH）复合物的XPB亚基，而该亚基正是超级增强子区域的核心组分。雷公藤甲素能够抑制大量超级增强子关联基因的表达，尤其针对致癌基因。值得注意的是，相较于其他卵巢癌及正常细胞类型，SCCOHT中高表达的SALL4基因在经雷公藤甲素短期处理后，其表达水平显著下调。在SCCOHT患者来源的异种移植模型中，雷公藤甲素及其前药衍生物米尼利德（minnelide）均可有效抑制肿瘤生长。本研究结果证实，表观遗传功能异常后超级增强子活性在SCCOHT的致癌过程中发挥关键作用，且可通过靶向其核心功能组分实现精准干预，例如采用雷公藤甲素抑制TFIIH活性。整体实验设计：针对BIN67、SCCOHT及COV434这三株SCCOHT细胞系，开展H3K27ac与IgG的CUT&RUN测序实验。