Table2_Identification of novel candidate targets for suppressing ovarian cancer progression through IL-33/ST2 axis components using the system biology approach.XLSX

Background: Cancer-associated fibroblasts (CAFs) of ovarian cancer (OvC) are the most prevalent element of the tumor microenvironment (TM). By promoting angiogenesis, immunological suppression, and invasion, CAFs speed up the growth of tumors by changing the extracellular matrix’s structure and composition and/or initiating the epithelial cells (EPT). IL-33/ST2 signaling has drawn a lot of attention since it acts as a pro-tumor alarmin and encourages spread by altering TM.
Methods: Differentially expressed genes (DEGs) of the OvC tumor microenvironment were found in the GEO database, qRT-PCR, western blotting, and immunohistochemistry, and their presence and changes in healthy and tumor tissue content were examined. Primary cultures of healthy fibroblasts and CAFs obtained from healthy and tumor tissues retrieved from OvC samples were used for in vitro and in vivo investigations. Cultured primary human CAFs were utilized to investigate the regulation and the IL-33/ST2 axis role in the inflammation reactions.
Results: Although ST2 and IL-33 expression was detected in both epithelial (EPT) and fibroblast cells of ovarian cancer, they are more abundant in CAFs. Lipopolysaccharides, serum amyloid A1, and IL-1β, the inflammatory mediators, could all induce IL-33 expression through NF-κB activation in human CAFs. In turn, via the ST2 receptor, IL-33 affected the production of IL-6, IL-1β, and PTGS2 in human CAFs via the MAPKs-NF-κB pathway.
Conclusion: Our findings suggest that IL-33/ST2 is affected by the interaction of CAFs and epithelial cells inside the tumor microenvironment. Activation of this axis leads to increased expression of inflammatory factors in tumor CAFs and EPT cells. Therefore, targeting the IL-33/ST2 axis could have potential value in the prevention of OvC progression.

背景：卵巢癌（ovarian cancer, OvC）相关癌相关成纤维细胞（cancer-associated fibroblasts, CAFs）是肿瘤微环境（tumor microenvironment, TM）中最为丰富的组成成分。CAFs可通过重构细胞外基质的结构与组成、激活上皮细胞（epithelial cells, EPT），并促进血管生成、免疫抑制与肿瘤侵袭，进而加速肿瘤增殖与进展。IL-33/ST2信号通路作为促肿瘤警报素，可通过重塑肿瘤微环境促进肿瘤转移，因此受到学界广泛关注。
方法：本研究从基因表达综合数据库（Gene Expression Omnibus, GEO）中筛选得到卵巢癌肿瘤微环境的差异表达基因（differentially expressed genes, DEGs），并通过实时定量聚合酶链反应（quantitative real-time polymerase chain reaction, qRT-PCR）、蛋白质印迹法（western blotting）与免疫组织化学（immunohistochemistry）验证其在正常组织与肿瘤组织中的表达水平与分布特征。我们采用从卵巢癌患者正常组织与肿瘤组织中分离得到的正常成纤维细胞与CAFs进行原代培养，开展体外与体内实验。此外，利用培养的原代人CAFs，探究IL-33/ST2轴的调控机制及其在炎症反应中的生物学功能。
结果：尽管卵巢癌上皮细胞与成纤维细胞中均可检测到ST2与IL-33的表达，但二者在CAFs中的表达丰度显著更高。炎症介质脂多糖、血清淀粉样蛋白A1与IL-1β均可通过激活人CAFs中的核因子κB（nuclear factor kappa-B, NF-κB）通路诱导IL-33的表达。反之，IL-33可通过ST2受体，经丝裂原活化蛋白激酶-核因子κB（MAPKs-NF-κB）通路调控人CAFs中IL-6、IL-1β与前列腺素内过氧化物合酶2（PTGS2）的合成与分泌。
结论：本研究结果表明，IL-33/ST2轴的表达受肿瘤微环境中CAFs与上皮细胞的相互作用调控。该通路的激活可上调肿瘤CAFs与上皮细胞内炎症因子的表达水平，因此靶向IL-33/ST2轴或可成为抑制卵巢癌进展的潜在治疗策略。