Saikosaponin A Induces Apoptosis in HCT116 Colorectal Cancer Cells via ROS-Mediated ER Stress and p38/JNK MAPK Pathway Activation: in Vitro and in Vivo Evidence

Abstract Colorectal cancer (CRC) is the third most prevalent cancer globally, with limited effective treatment options and significant chemotherapy resistance. Saikosaponin A (SSA), a triterpenoid saponin from Radix Bupleuri, exhibits anti-inflammatory and antitumor properties, but its mechanism of action in CRC remains undefined. This study aims to investigate SSA's antitumor effects against HCT116 CRC cells and elucidate the underlying molecular mechanisms through integrated omics analysis and functional validation. SSA selectively inhibited HCT116 proliferation and colony formation with minimal toxicity to HEK293 cells. SSA suppressed xenograft tumor growth by 54% (10 mg/kg) without affecting body weight or organ histology. Integrated omics revealed 6,033 DEGs and 39 DEMs, with 81 genes and 37 miRNAs significantly enriched in the MAPK pathway. SSA induced apoptosis in a dose-dependent manner, increasing ROS production 3.2-fold and decreasing MMP. Mechanistically, SSA activated p38 and JNK MAPK pathways, upregulated CHOP-mediated ER stress, and modulated apoptosis proteins (decreased Bcl-2, increased cleaved caspase-3 and -9). Network analysis identified miR-132-3p as a key regulator of MAPK hub genes (KRAS, SOS1, BRAF). SSA exerts potent antitumor activity against HCT116 CRC cells, representing a promising therapeutic candidate for CRC treatment.