Wu Meng-Yao, Luo Yu-Xin, Jia Wen-Xiu, Wang Dan-Dan, Sun Dong-Lei, Song Jia, Wang Jing, Niu Wei-Wei, Zhang Xiao-Lan
Department of Gastroenterology, The Second Hospital of Hebei Medical University, Hebei Key Laboratory of Gastroenterology, Hebei Institute of Gastroenterology, Hebei Clinical Research Center for Digestive Diseases, Hebei Medical University, Shijiazhuang, China.
J Gastrointest Oncol. 2022 Apr;13(2):695-709. doi: 10.21037/jgo-22-237.
Colitis-associated colorectal cancer (CAC) is a serious complication of inflammatory bowel disease (IBD). microRNA-320 (miRNA-320) promotes intestinal mucosal barrier repair in IBD and inhibits tumor progression. However, the role of miRNA-320 in the progression of CAC remains to be defined. We studied the mechanisms of miRNA-320 in the progression of CAC in mice.
CAC was induced in mice (C57BL/B6) by the administration of azoxymethane (AOM) and dextran sulfate sodium (DSS), and the mice were given a lentiviral vector (LV) overexpressing mmu-miRNA-320. The level of miRNA-320 was analyzed by quantitative real-time polymerase chain reaction (qPCR). Colonic inflammation, histological analysis, and tumorigenesis were evaluated. Ki-67 in colonic tissues was examined by immunohistochemistry. B-cell lymphoma-extra large (BCL-xl) and proliferating cell nuclear antigen (PCNA) expression was examined by Western blot. Furthermore, the proliferation, migration, and invasion of colorectal cancer (CRC) cells were evaluated. The levels of interleukin-6 receptor (IL-6R), signal transducer and activator of transcription 3 (STAT3), and phosphorylated-signal transducer and activator of transcription 3 (p-STAT3) were examined by Western blot and qPCR.
miRNA-320 was downregulated in CAC mice (0.57±0.13 1.00±0.12, =-5.95, P<0.001). miRNA-320 decreased the disease activity index (DAI) scores, improved colonic inflammation, and inhibited tumor formation (tumor number: 8.00±2.90 13.67±2.73, =-3.49, P<0.01) in mice with CAC. miRNA-320 suppressed the expression of BCL-xl, PCNA, and Ki-67 (0.38±0.07 0.69±0.08, =-7.30, P<0.001). miRNA-320 inhibited colon cancer cell proliferation, migration, and invasion. miRNA-320 significantly inhibited the levels of IL-6R [colon tissue messenger RNA (mRNA): 4.06±1.44 10.05±1.55, =-6.94, P<0.001], STAT3, and p-STAT3 and . Silencing IL-6R expression partially reversed the IL-6R/STAT3-suppressing and tumor-inhibiting effect of miRNA-320.
miRNA-320 inhibits tumorigenesis in mice with CAC by suppressing IL-6R/STAT3 expression, and IL-6R is a target gene of miRNA-320.
结肠炎相关结直肠癌（CAC）是炎症性肠病（IBD）的一种严重并发症。微小RNA-320（miRNA-320）可促进IBD中肠黏膜屏障修复并抑制肿瘤进展。然而，miRNA-320在CAC进展中的作用仍有待明确。我们研究了miRNA-320在小鼠CAC进展中的机制。
通过给予小鼠（C57BL/B6）氧化偶氮甲烷（AOM）和葡聚糖硫酸钠（DSS）诱导CAC，并给小鼠注射过表达mmu-miRNA-320的慢病毒载体（LV）。通过定量实时聚合酶链反应（qPCR）分析miRNA-320的水平。评估结肠炎症、组织学分析和肿瘤发生情况。通过免疫组织化学检测结肠组织中的Ki-67。通过蛋白质免疫印迹法检测B细胞淋巴瘤-特大号（BCL-xl）和增殖细胞核抗原（PCNA）的表达。此外，评估结直肠癌（CRC）细胞的增殖、迁移和侵袭能力。通过蛋白质免疫印迹法和qPCR检测白细胞介素-6受体（IL-6R）、信号转导和转录激活因子3（STAT3）以及磷酸化信号转导和转录激活因子3（p-STAT3）的水平。
CAC小鼠中miRNA-320表达下调（0.57±0.13比1.00±0.12，t=-5.95，P<0.001）。miRNA-320降低了疾病活动指数（DAI）评分，改善了结肠炎症，并抑制了CAC小鼠的肿瘤形成（肿瘤数量：8.00±2.90比13.67±2.73，t=-3.49，P<0.01）。miRNA-320抑制了BCL-xl、PCNA和Ki-67的表达（0.38±0.07比0.69±0.08，t=-7.30，P<0.001）。miRNA-320抑制结肠癌细胞的增殖、迁移和侵袭。miRNA-320显著抑制了IL-6R[结肠组织信使核糖核酸（mRNA）：4.06±1.44比10.05±1.55，t=-6.94，P<0.001]、STAT3和p-STAT3的水平。沉默IL-6R表达部分逆转了miRNA-320对IL-6R/STAT3的抑制作用和肿瘤抑制作用。
miRNA-320通过抑制IL-6R/STAT3表达抑制CAC小鼠的肿瘤发生，且IL-6R是miRNA-320的靶基因。
