Transcriptome Profiling Reveals the Antitumor Mechanism of Polysaccharide from Marine Algae <i>Gracilariopsis lemaneiformis</i>

Seaweed is one of the important biomass producers and possesses active metabolites with potential therapeutic effects against tumors. The red alga Gracilariopsis lemaneiformis (Gp. lemaneiformis) possesses antitumor activity, and the polysaccharide of Gp. lemaneiformis (PGL) has been demonstrated to be an ingredient with marked anticancer activity. However, the anticancer mechanism of PGL remains to be elucidated. In this study, we analyzed the inhibitory effect of PGL on the cell growth of 3 human cancer cell lines and found that PGL inhibited cell proliferation, reduced cell viability, and altered cell morphology in a time- and concentration-dependent manner. Our transcriptome analysis indicates that PGL can regulate the expression of 758 genes, which are involved in apoptosis, the cell cycle, nuclear division, and cell death. Furthermore, we demonstrated that PGL induced apoptosis and cell cycle arrest and modulated the expression of related genes in the A549 cell line. Our work provides a framework to understand the effects of PGL on cancer cells, and can serve as a resource for delineating the antitumor mechanisms of Gp. lemaneiformis.海藻是重要的生物质来源之一，其所含活性代谢产物具备潜在的抗肿瘤治疗活性。红藻龙须菜（Gracilariopsis lemaneiformis，以下简称Gp. lemaneiformis）具有抗肿瘤活性，其多糖组分（Gracilariopsis lemaneiformis polysaccharide，以下简称PGL）已被证实具备显著的抗癌活性。然而，PGL的抗癌分子机制仍有待阐明。本研究分析了PGL对3种人源癌细胞系的增殖抑制作用，发现PGL可通过时间与浓度依赖的方式抑制细胞增殖、降低细胞活力并改变细胞形态。转录组分析结果显示，PGL可调控758个基因的表达，这些基因涉及细胞凋亡、细胞周期、核分裂与细胞死亡等生物学过程。进一步实验证实，PGL可诱导A549细胞系发生凋亡与细胞周期阻滞，并调控相关基因的表达。本研究为解析PGL对癌细胞的作用机制提供了研究框架，同时可为阐明龙须菜的抗肿瘤机制提供重要参考资源。