Structural characterization of the polysaccharide from the black crystal region of Inonotus obliquus and its effect on AsPC-1 and SW1990 pancreatic cancer cell apoptosis

In this study, one water soluble polysaccharide (IOP1–1) with a weight average molecular weight of 6886 Da was obtained from the black crystal region of Inonotus obliquus by hot water extraction, DEAE-52 cellulose extraction and Sephadex-100 column chromatography purification. Structural analysis indicated that IOP1–1 was a glucan with a main chain composed of α-Glcp-(1 → 4)-α-Glcp-(1 → 4)-β-Glcp-(1 → 4)-β-Glcp-(1 → 4)-α-Glcp-(1 → 6)-β-Glcp-(1 → 4)-α-Glcp-(1 → 3)-β-Glcp-(1→. The CCK-8 assay results showed that IOP1–1 inhibited AsPC-1 and SW1990 pancreatic cancer cell proliferation in a concentration-dependent manner. Flow cytometric analysis revealed that IOP1–1 induced cell cycle arrest in AsPC-1 and SW1990 cells. Hoechst 33342 staining and Annexin V-FITC/PI double staining analysis showed that IOP1–1 could induce apoptosis in AsPC-1 and SW1990 cells. Furthermore, western blot analysis confirmed that IOP1–1 could induce apoptosis in AsPC-1 and SW1990 pancreatic cancer cells through three pathways: the mitochondrial pathway, the death receptor pathway, and endoplasmic reticulum stress. According to these research data, IOP1–1 may be utilized as an adjuvant treatment to anticancer medications, opening up new application prospects and opportunities.