Wang Jie, Liu Hancong, Zhu Liuchong, Wang Jingyi, Luo Xiongming, Liu Wenbin, Ma Yan
School of Biosciences & Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510000, China.
Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances, 280 Wai Huan Dong Road, Guangzhou Higher Education Mega Center, Guangzhou 510000, China.
Molecules. 2022 Oct 26;27(21):7281. doi: 10.3390/molecules27217281.
Hepatocellular carcinoma (HCC) is the most common primary liver malignant tumor, and the targeted therapy for HCC is very limited. Our previous study demonstrated that prodigiosin(PG), a secondary metabolite from Serratia marcescens found in the intestinal flora of cockroaches, inhibits the proliferation of HCC and increases the expression of CHOP, a marker protein for endoplasmic reticulum stress (ERS)-mediated apoptosis, in a dose-dependent manner. However, the mechanisms underlying the activity of PG in vivo and in vitro are unclear. This study explored the molecular mechanisms of PG-induced ERS against liver cancer in vitro and in vivo. The apoptosis of hepatocellular carcinoma cells induced by PG through endoplasmic reticulum stress was observed by flow cytometry, colony formation assay, cell viability assay, immunoblot analysis, and TUNEL assay. The localization of PG in cells was observed using laser confocal fluorescence microscopy. Flow cytometry was used to detect the intracellular Ca concentration after PG treatment. We found that PG could promote apoptosis and inhibit the proliferation of HCC. It was localized in the endoplasmic reticulum of HepG2 cells, where it induces the release of Ca. PG also upregulated the expression of key unfolded response proteins, including PERK, IRE1α, Bip, and CHOP, and related apoptotic proteins, including caspase3, caspase9, and Bax, but down-regulated the expression of anti-apoptotic protein Bcl-2 in liver cancer. Alleviating ERS reversed the above phenomenon. PG had no obvious negative effects on the functioning of the liver, kidney, and other main organs in nude mice, but the growth of liver cancer cells was inhibited by inducing ERS in vivo. The findings of this study showed that PG promotes apoptosis of HCC by inducing ERS.
肝细胞癌（HCC）是最常见的原发性肝脏恶性肿瘤，而针对HCC的靶向治疗非常有限。我们之前的研究表明，灵菌红素（PG）是一种在蟑螂肠道菌群中发现的粘质沙雷氏菌的次生代谢产物，它以剂量依赖的方式抑制HCC的增殖，并增加内质网应激（ERS）介导的凋亡的标志物蛋白CHOP的表达。然而，PG在体内和体外发挥作用的机制尚不清楚。本研究探讨了PG诱导的ERS在体外和体内抗肝癌的分子机制。通过流式细胞术、集落形成试验、细胞活力试验、免疫印迹分析和TUNEL试验观察PG通过内质网应激诱导的肝癌细胞凋亡情况。使用激光共聚焦荧光显微镜观察PG在细胞内的定位。采用流式细胞术检测PG处理后细胞内Ca浓度。我们发现PG可促进肝癌细胞凋亡并抑制其增殖。它定位于HepG2细胞的内质网中，并在那里诱导Ca的释放。PG还上调了关键的未折叠反应蛋白（包括PERK、IRE1α、Bip和CHOP）以及相关凋亡蛋白（包括caspase3、caspase９和Bax）的表达，但下调了肝癌中抗凋亡蛋白Bcl-2的表达。减轻ERS可逆转上述现象。PG对裸鼠肝脏、肾脏等主要器官的功能没有明显负面影响，但通过在体内诱导ERS抑制了肝癌细胞的生长。本研究结果表明，PG通过诱导ERS促进肝癌细胞凋亡。
