Department of Pharmacology, Zhongshan School of Medicine, Sun Yat‑Sen University, Guangzhou, Guangdong 510080, P.R. China.
Department of Urology, The Eighth Affiliated Hospital, Sun Yat‑Sen University, Shenzhen, Guangdong 518033, P.R. China.
Int J Oncol. 2022 Jan;60(1). doi: 10.3892/ijo.2021.5300. Epub 2021 Dec 31.
The roles of gap junctions (GJs) and its components, connexins, in the autophagy of cervical cancer cells have been rarely investigated. Our previous study demonstrated that connexin 32 (Cx32) exerted an anti‑apoptotic effect on cervical cancer. However, as an important regulator of apoptosis, whether the autophagy is involved in the function of Cx32 on cervical cancer cells is not well defined. The present study aimed to investigate the role of Cx32 on autophagy and apoptosis inhibition in cervical cancer cells. The expression levels of Cx32 and the autophagy‑associated protein LC3‑Ⅱ in paracancerous cervical tissues (n=30) and cervical cancer (n=50) tissues were determined via western blotting. In total, 45 cervical cancer specimens were used to evaluate the clinical relevance of Cx32 and LC3‑Ⅱ. It was found that both Cx32 and LC3‑Ⅱ were upregulated in cervical cancer tissues compared with those in paracancerous cervical tissues. The effect of Cx32 on autophagy was examined by detecting the change of LC3‑Ⅱ using western blotting, transfection with enhanced green fluorescent protein‑LC3 plasmid and transmission electron microscopy analysis. Overexpression of Cx32 significantly enhanced autophagy in HeLa‑Cx32 cells, whereas knockdown of Cx32 suppressed autophagy in C‑33A cells. The flow cytometry results demonstrated that Cx32 inhibited the apoptosis of cervical cancer cells by promoting autophagy. Moreover, Cx32 triggered autophagy via the activation of the AMP‑activated protein kinase (AMPK) signalling, regardless of the presence or absence of GJs. Collectively, it was identified that Cx32 exerted its anti‑apoptotic effect by activating autophagy via the AMPK pathway in cervical cancer, which demonstrates a novel mechanism for Cx32 in human cervical cancer progression.
缝隙连接（GJ）及其组成部分连接蛋白在宫颈癌细胞自噬中的作用很少被研究。我们之前的研究表明，连接蛋白 32（Cx32）对宫颈癌具有抗凋亡作用。然而，作为凋亡的重要调节因子，Cx32 是否参与了宫颈癌细胞的自噬过程尚不清楚。本研究旨在探讨 Cx32 对宫颈癌细胞自噬和凋亡抑制的作用。通过蛋白质印迹法测定了癌旁宫颈组织（n=30）和宫颈癌组织（n=50）中 Cx32 和自噬相关蛋白 LC3-Ⅱ的表达水平。共使用 45 例宫颈癌标本评估 Cx32 和 LC3-Ⅱ的临床相关性。结果发现，与癌旁宫颈组织相比，宫颈癌组织中 Cx32 和 LC3-Ⅱ均上调。通过蛋白质印迹法检测 LC3-Ⅱ的变化、转染增强型绿色荧光蛋白-LC3 质粒和透射电镜分析来检测 Cx32 对自噬的影响。Cx32 的过表达显著增强了 HeLa-Cx32 细胞的自噬，而 Cx32 的敲低则抑制了 C-33A 细胞的自噬。流式细胞术结果表明，Cx32 通过促进自噬抑制宫颈癌细胞的凋亡。此外，Cx32 通过激活 AMP 激活的蛋白激酶（AMPK）信号通路触发自噬，而与 GJ 的存在与否无关。综上所述，Cx32 通过 AMPK 通路激活自噬发挥其抗凋亡作用，为 Cx32 在人类宫颈癌进展中的作用提供了新的机制。
