Department of Gastroenterology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts.
Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts.
Gastroenterology. 2022 Jan;162(1):209-222. doi: 10.1053/j.gastro.2021.09.044. Epub 2021 Sep 25.
Genomic alterations that encourage stem cell activity and hinder proper maturation are central to the development of colorectal cancer (CRC). Key molecular mediators that promote these malignant properties require further elucidation to galvanize translational advances. We therefore aimed to characterize a key factor that blocks intestinal differentiation, define its transcriptional and epigenetic program, and provide preclinical evidence for therapeutic targeting in CRC.
Intestinal tissue from transgenic mice and patients were analyzed by means of histopathology and immunostaining. Human CRC cells and neoplastic murine organoids were genetically manipulated for functional studies. Gene expression profiling was obtained through RNA sequencing. Histone modifications and transcription factor binding were determined with the use of chromatin immunoprecipitation sequencing.
We demonstrate that SRY-box transcription factor 9 (SOX9) promotes CRC by activating a stem cell-like program that hinders intestinal differentiation. Intestinal adenomas and colorectal adenocarcinomas from mouse models and patients demonstrate ectopic and elevated expression of SOX9. Functional experiments indicate a requirement for SOX9 in human CRC cell lines and engineered neoplastic organoids. Disrupting SOX9 activity impairs primary CRC tumor growth by inducing intestinal differentiation. By binding to genome wide enhancers, SOX9 directly activates genes associated with Paneth and stem cell activity, including prominin 1 (PROM1). SOX9 up-regulates PROM1 via a Wnt-responsive intronic enhancer. A pentaspan transmembrane protein, PROM1 uses its first intracellular domain to support stem cell signaling, at least in part through SOX9, reinforcing a PROM1-SOX9 positive feedback loop.
These studies establish SOX9 as a central regulator of an enhancer-driven stem cell-like program and carry important implications for developing therapeutics directed at overcoming differentiation defects in CRC.
促进干细胞活性并阻碍正常成熟的基因组改变是结直肠癌（CRC）发展的核心。需要进一步阐明促进这些恶性特性的关键分子介质，以推动转化进展。因此，我们旨在表征阻止肠道分化的关键因素，定义其转录和表观遗传程序，并为 CRC 的治疗靶向提供临床前证据。
通过组织病理学和免疫染色分析转基因小鼠和患者的肠道组织。对人类 CRC 细胞和肿瘤源性类器官进行遗传操作以进行功能研究。通过 RNA 测序获得基因表达谱。使用染色质免疫沉淀测序确定组蛋白修饰和转录因子结合。
我们证明 SOX9 通过激活阻止肠道分化的干细胞样程序来促进 CRC。来自小鼠模型和患者的肠腺瘤和结直肠腺癌显示出 SOX9 的异位和上调表达。功能实验表明 SOX9 是人类 CRC 细胞系和工程化肿瘤类器官所必需的。通过诱导肠道分化，破坏 SOX9 活性可损害原发性 CRC 肿瘤的生长。通过与全基因组增强子结合，SOX9 直接激活与 Paneth 和干细胞活性相关的基因，包括 Prominin 1（PROM1）。SOX9 通过 Wnt 反应性内含子增强子上调 PROM1。PROM1 是一种五跨膜蛋白，其第一个细胞内结构域用于支持干细胞信号传导，至少部分通过 SOX9 增强 PROM1-SOX9 正反馈回路。
这些研究确立了 SOX9 作为增强子驱动的干细胞样程序的核心调节剂，并对开发针对 CRC 分化缺陷的治疗方法具有重要意义。
