Hao-Yu Dai, Ting-Ting Liu, Yi-Wei Cao, Ai-Hua Sui, Xiao-Hui Yang, Cun-Zhi Lin
The Affiliated Hospital of Qingdao University, China.
Integr Cancer Ther. 2025 Jan-Dec;24:15347354251341442. doi: 10.1177/15347354251341442. Epub 2025 Jun 6.
Holothurian glycosaminoglycan (hGAG) is an extract from the body wall of sea cucumber and previous studies have proved many unique bioactivities of it, such as anti-tumor, anti-coagulation and immune regulation. Previous studies of our research group have shown hGAG promoted cell apoptosis in human lung adenocarcinoma A549 cells by upregulating Bax and caspase-3 and downregulating Bcl-2, indicating mitochondrial apoptosis pathway participated in the process. In the mitochondrial apoptosis pathway, Bim induces cell apoptosis by either direct activation of pro-apoptotic Bax/Bak or neutralization of anti-apoptotic Bcl-2 proteins. The transcription of Bim was regulated by FOXO3a. Akt, one of the most important cellular signaling molecules, regulates apoptosis through its phosphorylation. Phosphorylation of Akt results in translocation of FOXO3a from nuclear to cytoplasm. This study aimed to explore the mechanism by which hGAG induced apoptosis in A549 cells, focusing on its regulation of the Akt/FOXO3a/Bim signaling pathway.
A549 cells were divided into three groups: control group, hGAG group and hGAG+SC79 (an Akt activator) group. Cell proliferation was detected by CCK-8 assay. Cell apoptosis was detected by flow cytometry. mRNA and protein expression levels were detected by Real-time Fluorescence Quantitative PCR and Western blotting assay, respectively. Protein localization was detected by immunofluorescence.
The results showed that hGAG induced apoptosis in A549 cells by downregulating p-Akt level, promoting FOXO3a expression, preventing FOXO3a nuclear export, and upregulating Bim expression, while SC79 reversed these effects, further demonstrating that hGAG regulated FOXO3a and Bim through inhibition of phosphorylation of Akt.
In conclusion, our data demonstrated that hGAG promoted apoptosis in A549 cells via the Akt/FOXO3a/Bim-mediated intrinsic apoptosis pathway.
海参糖胺聚糖（hGAG）是从海参体壁中提取的物质，以往研究已证实其具有多种独特的生物活性，如抗肿瘤、抗凝血和免疫调节作用。我们研究小组之前的研究表明，hGAG通过上调Bax和caspase - 3以及下调Bcl - 2促进人肺腺癌A549细胞凋亡，表明线粒体凋亡途径参与了这一过程。在线粒体凋亡途径中，Bim通过直接激活促凋亡的Bax/Bak或中和抗凋亡的Bcl - 2蛋白来诱导细胞凋亡。Bim的转录受FOXO3a调控。Akt是最重要的细胞信号分子之一，通过其磷酸化调节细胞凋亡。Akt的磷酸化导致FOXO3a从细胞核转移到细胞质。本研究旨在探讨hGAG诱导A549细胞凋亡的机制，重点关注其对Akt/FOXO3a/Bim信号通路的调控。
将A549细胞分为三组：对照组、hGAG组和hGAG + SC79（一种Akt激活剂）组。采用CCK - 8法检测细胞增殖。通过流式细胞术检测细胞凋亡。分别采用实时荧光定量PCR和蛋白质免疫印迹法检测mRNA和蛋白质表达水平。通过免疫荧光检测蛋白质定位。
结果显示，hGAG通过下调p - Akt水平、促进FOXO3a表达、阻止FOXO3a核输出以及上调Bim表达诱导A549细胞凋亡，而SC79可逆转这些作用，进一步证明hGAG通过抑制Akt磷酸化来调控FOXO3a和Bim。
总之，我们的数据表明hGAG通过Akt/FOXO3a/Bim介导的内源性凋亡途径促进A549细胞凋亡。
