Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China.
Department of Pharmacy, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China.
Mol Med Rep. 2019 May;19(5):3941-3947. doi: 10.3892/mmr.2019.10002. Epub 2019 Mar 1.
Butyrate, a histone deacetylase inhibitor, is a typical short chain fatty acid produced by gut microbiota, the dysmetabolism of which has been consistently associated with colorectal diseases. However, its role in tumorigenesis and progression of colorectal cancer cells remains under‑investigated. The present study examined the antitumor function of butyrate in the colorectal cancer cell line HCT116 and investigated the underlying molecular mechanism. MTT assay was used to measure cell proliferation and ELISA assay was used to determine cell apoptosis by measuring histone release and caspase‑3 activation. The results demonstrated that butyrate treatment significantly inhibited proliferation and induced apoptosis in HCT116 cells with an increased B‑cell lymphoma-2 (Bcl‑2)‑associated X protein/Bcl‑2 ratio. Western blotting demonstrated that the phosphorylation of mammalian target of rapamycin (mTOR) at Ser2448, ribosomal protein S6 kinase β‑1 (S6K1) at Thr389, S6 at Ser235/236 and expression of silent mating type information regulation 2 homolog (SIRT)1 were decreased following butyrate treatment, while the acetylation of S6K1 was indicated to be increased. Silencing of SIRT1 by small interfering RNA technology demonstrated a similar inhibition on growth, induction of apoptosis, elevation of S6K1 acetylation and deactivation of mTOR/S6K1 signaling. Butyrate treatment also enhanced the inhibition of SIRT1 silencing on cell proliferation and activity of mTOR/S6K1. The activation of mTOR/S6K1 signaling and upregulation of cell proliferation mediated by overexpression of SIRT1 were blocked by butyrate. These data suggested that butyrate inhibited proliferation and induced apoptosis in HCT116 cells by deactivating mTOR/S6K1 signaling, possibly through its inhibition of SIRT1.
丁酸盐是一种组蛋白去乙酰化酶抑制剂，是肠道微生物群产生的一种典型的短链脂肪酸，其代谢失调与结直肠疾病一直密切相关。然而，其在结直肠癌细胞发生和进展中的作用仍未得到充分研究。本研究探讨了丁酸盐在结直肠癌细胞系 HCT116 中的抗肿瘤作用，并研究了其潜在的分子机制。MTT 法用于测量细胞增殖，ELISA 法用于通过测量组蛋白释放和 caspase-3 激活来测定细胞凋亡。结果表明，丁酸盐处理显著抑制 HCT116 细胞的增殖并诱导其凋亡，同时增加 B 细胞淋巴瘤-2（Bcl-2）相关 X 蛋白/Bcl-2 比值。Western blot 分析表明，丁酸盐处理后哺乳动物雷帕霉素靶蛋白（mTOR）在 Ser2448 位点的磷酸化、核糖体蛋白 S6 激酶β-1（S6K1）在 Thr389 位点的磷酸化、S6 在 Ser235/236 位点的磷酸化以及沉默交配型信息调节 2 同源物（SIRT）1 的表达均降低，而 S6K1 的乙酰化水平则升高。用小干扰 RNA 技术沉默 SIRT1 可导致生长抑制、凋亡诱导、S6K1 乙酰化水平升高和 mTOR/S6K1 信号失活类似。丁酸盐处理还增强了 SIRT1 沉默对细胞增殖和 mTOR/S6K1 活性的抑制作用。SIRT1 的过表达介导的 mTOR/S6K1 信号的激活和细胞增殖的上调被丁酸盐阻断。这些数据表明，丁酸盐通过失活 mTOR/S6K1 信号抑制 HCT116 细胞的增殖并诱导其凋亡，可能是通过抑制 SIRT1 实现的。
