Table_6_MiR-21-5p Induces Pyroptosis in Colorectal Cancer via TGFBI.docx

Pyroptosis is a distinct form of programmed cell death in eukaryotic cells that has garnered increasing attention in cancer-related research. Moreover, although miR-21 has been reported as abnormally expressed in colorectal cancer, due to a lack of in-depth research on the transcriptional regulation mechanisms of miR-21, its clinical usage remains limited. Our study is the first, to our knowledge, to compare the clinical manifestations and laboratory phenotypes associated with miR-21-3p and miR-21-5p. Morphologically, the transfection of miR-21-3p or miR-21-5p inhibitors, as well as miR-21-5p mimics into HCT-116 and HT-29 cell lines, induced cell death. Surprisingly, overexpression of miR-21-5p induced cell death more strongly than its knockdown. Mechanistic studies of miR-21-5p overexpression revealed that various inflammatory factors including IL-1β and IL-18 were released, while pyroptosis-associated mRNAs were upregulated and proteins were activated. Moreover, miR-21-5p was found to act as a downstream factor to significantly and directly regulate transforming growth factor beta-induced (TGFB1). Specifically, miR-21-5p overexpression caused downregulation of TGFBI, which may have led to pyroptosis. Collectively, we revealed that miR-21-5p induces pyroptosis in colorectal cancer via TGFBI regulation, thereby providing important mechanistic insights into its antitumor effects and expanding its potential for clinical applications.

细胞焦亡（pyroptosis）是真核细胞中一种独特的程序性细胞死亡形式，在肿瘤相关研究中受到日益广泛的关注。尽管已有研究证实miR-21在结直肠癌中存在异常表达，但由于对miR-21的转录调控机制缺乏深入探究，其临床应用仍受到限制。据我们所知，本研究首次对比了miR-21-3p与miR-21-5p相关的临床表现与实验室表型。在形态学层面，将miR-21-3p或miR-21-5p抑制剂、以及miR-21-5p模拟物转染至HCT-116与HT-29细胞系后，可诱导细胞死亡。令人意外的是，miR-21-5p过表达诱导的细胞死亡效应较其敲低更为显著。针对miR-21-5p过表达的机制研究显示，包括IL-1β、IL-18在内的多种炎症因子被释放，同时焦亡相关mRNA表达上调、蛋白被激活。此外，研究发现miR-21-5p作为下游因子，可显著且直接调控转化生长因子β诱导蛋白（transforming growth factor beta-induced, TGFBI）。具体而言，miR-21-5p过表达会导致TGFBI表达下调，这可能是引发细胞焦亡的关键诱因。综上，本研究揭示了miR-21-5p通过调控TGFBI诱导结直肠癌细胞发生焦亡，从而为其抗肿瘤效应提供了重要的机制阐释，并拓展了其临床应用潜力。