Department of General Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China.
Oncol Rep. 2020 Apr;43(4):1053-1066. doi: 10.3892/or.2020.7494. Epub 2020 Feb 7.
Colorectal cancer (CRC) is one of the most common digestive tract tumors worldwide. Catalpol exerts inhibitory effects on the progression of several cancer types by regulating microRNAs (miRs). However, the precise role and carcinostatic mechanism of catalpol on CRC cells are poorly understood which limits the application of catalpol treatment. In the present study, miR‑34a and sirtuin 1 (SIRT1) expression levels were detected in CRC tissues and CRC cell lines by RT‑qPCR. Computational software analysis, luciferase assays and western blotting were used to demonstrate the downstream target of miR‑34a in CRC cells. Effects of catalpol on cell viability, apoptosis, autophagic flux and the miR‑34a/SIRT1 axis in the CRC cells were assessed by CCK‑8 assay, flow cytometry, electron microscopy and western blotting, respectively. Whether the miR‑34a/SIRT1 axis participated in catalpol‑mediated autophagy and apoptosis was investigated. The effects of catalpol on the miR‑34a/SIRT1 axis and malignant behavior were evaluated in a rat model of azoxymethane (AOM)‑induced CRC. It was revealed that miR‑34a expression levels were significantly decreased while SIRT1 was overexpressed in most of the CRC tissues and all the CRC cell lines. Clinically, a low level of miR‑34a was correlated with poor clinicopathological characteristics in CRC patients. Catalpol reduced cell viability, suppressed autophagy, promoted apoptosis, and regulated the expression of SIRT1 by inducing miR‑34a in vitro and in vivo. The autophagy‑inhibiting effect of catalpol may be a mechanism to promote apoptosis of CRC cells. miR‑34a mimic transfection resulted in autophagy‑suppressive activity similar to that of catalpol, while the miR‑34a inhibitor attenuated the antiautophagic effects of catalpol. In conclusion, miR‑34a is involved in regulating catalpol‑mediated autophagy and malignant behavior by directly inhibiting SIRT1 in CRC.
结直肠癌（CRC）是全球最常见的消化道肿瘤之一。梓醇通过调节 microRNAs（miRs）对几种癌症类型的进展发挥抑制作用。然而，梓醇对 CRC 细胞的精确作用和抗癌机制仍知之甚少，这限制了梓醇治疗的应用。在本研究中，通过 RT-qPCR 检测 CRC 组织和 CRC 细胞系中的 miR-34a 和 SIRT1 表达水平。使用计算软件分析、荧光素酶测定和 Western blot 来证明 miR-34a 在 CRC 细胞中的下游靶标。通过 CCK-8 测定、流式细胞术、电子显微镜和 Western blot 分别评估梓醇对 CRC 细胞活力、细胞凋亡、自噬通量以及 miR-34a/SIRT1 轴的影响。研究了 miR-34a/SIRT1 轴是否参与梓醇介导的自噬和细胞凋亡。通过阿霉素（AOM）诱导的 CRC 大鼠模型评估梓醇对 miR-34a/SIRT1 轴和恶性行为的影响。结果表明，在大多数 CRC 组织和所有 CRC 细胞系中，miR-34a 的表达水平显著降低，而 SIRT1 则过表达。临床上，CRC 患者 miR-34a 水平低与不良临床病理特征相关。梓醇在体外和体内通过诱导 miR-34a 降低细胞活力、抑制自噬、促进凋亡并调节 SIRT1 的表达。梓醇的自噬抑制作用可能是促进 CRC 细胞凋亡的一种机制。miR-34a 模拟物转染导致自噬抑制活性类似于梓醇，而 miR-34a 抑制剂减弱了梓醇的抗自噬作用。总之，miR-34a 通过直接抑制 CRC 中的 SIRT1 参与调节梓醇介导的自噬和恶性行为。
