α-Santonin from a marine sponge exhibits anticancer activity and mechanistic effects in colorectal cancer

Abstract

Colorectal cancer (CRC) requires new therapeutic agents with minimal systemic toxicity. Marine-derived natural products represent a promising source of drug candidates because of their unique bioactivity. This study evaluated the anti-tumor potential and possible molecular mechanisms of α-santonin, a sesquiterpene lactone (C15H18O3) isolated from the marine sponge Dysidea avara , using in vivo and in silico approaches. α-Santonin (92% purity, confirmed by GC-MS peak area normalization) was isolated from Dysidea avara . Its selective cytotoxicity was assessed in CT26 cells and normal MRC5 fibroblasts using the MTT assay. BALB/c mice bearing CT26-induced CRC tumors received intratumoral α-santonin (2, 3, or 4 mg/kg) or PBS twice weekly for three weeks. Tumor volume, cytokine levels by ELISA, and gene expression of apoptotic, metastatic, and angiogenic markers by RT-qPCR were evaluated. Molecular docking against JAK2 and PHD, together with ADME profiling, was performed to explore possible binding interactions and pharmacokinetic properties. α-Santonin showed selective cytotoxicity, with a selectivity index of 3.36 (IC 50 : 216.25 µg/mL in CT26 cells vs. 727.50 µg/mL in MRC5 fibroblasts). In vivo , the 4 mg/kg dose produced the greatest reduction in tumor volume compared with the control group. The compound also modulated systemic immune responses by decreasing pro-tumor IL-4 by 40% and increasing anti-tumor IFN-γ by 2.9-fold in splenocytes. At the molecular level, α-santonin increased Bax expression 3.8-fold and decreased Bcl-2 expression 2.5-fold, consistent with induction of apoptosis. It also significantly downregulated MMP-2 , MMP-9 , VEGF , and HIF-1α , suggesting inhibition of metastasis and angiogenesis. Computational analysis indicated favorable predicted binding affinities for PHD (− 7.88 kcal/mol) and JAK2 (− 7.80 kcal/mol), alongside favorable ADME characteristics. α-Santonin demonstrates significant anti-tumor activity in a murine CRC model through immune modulation, apoptosis induction, and downregulation of angiogenesis- and metastasis-related markers. Computational docking provides a structural hypothesis suggesting that JAK2 and PHD may serve as potential targets; however, these interactions are strictly predictive and require independent experimental validation.