Mechanism-driven nano-therapeutic platform integrating plant-derived compounds and membrane-active peptides reprograms inflammatory, cell cycle arrest, cGAS–STING, and apoptotic gene expression to quench colorectal cancer

Colorectal cancer (CRC) remains one of the leading causes of cancer-related mortality worldwide, and its first-line chemotherapeutic, 5-fluorouracil (5-FU), is constrained by poor tumor selectivity, dose-limiting systemic toxicity, and the frequent emergence of drug resistance. Nanocarrier-based co-delivery of naturally derived, multi-targeted agents offers a promising strategy to enhance efficacy while limiting off-target harm. This study evaluated the antitumor effects of nanoformulated liposomal melittin peptides (LIP-MLT) and niosomal chrysin (NsCR), administered as monotherapy or as combined therapy (LIP-MLT/NsCR), against DMH-induced CRC in a rat model. CRC was induced by subcutaneous injection of DMH (1,2-dimethylhydrazine, 40 mg/kg, twice weekly) for 8 weeks. Sprague-Dawley rats (n = 120) were randomly divided into six groups: healthy control (CON); untreated colorectal tumour (CR-TUM); and DMH-induced rats treated with 5-fluorouracil (CR-TUM + FU5), liposomal melittin (CR-TUM + LIP-MLT), niosomal chrysin (CR-TUM + NsCR), or the combination (CR-TUM + LIP-MLT/NsCR). Oxidant/antioxidant status, inflammatory cytokines, and the transcriptional profiles of inflammatory, cell-cycle-arrest, apoptotic/antiapoptotic, cGAS – STING innate-sensing, mTOR , and angiogenesis/metastasis genes were assessed, together with histopathological and immunohistochemical evaluation. The untreated CR-TUM group showed pronounced tumor-markers elevation, anemia, oxidative damage, and a strong pro-inflammatory, immunosuppressive shift. Relative to CR-TUM, LIP-MLT/NsCR lowered the tumor markers CEA (3.1-fold), CA19-9 (3.5-fold), and CCSA (2.1-fold), and reduced the oxidative markers ROS (2.2-fold), MDA (1.8-fold), and NO (2.2-fold) while raising the antioxidants. It also decreased the pro-inflammatory mediators NF-κB (2.3-fold), IL - 1 β (2.4-fold), and TNF -α (1.7-fold) versus CR-TUM, reversing approximately 71% of the DMH-induced inflammatory signature. At the transcriptional level, the combination produced the strongest upregulation of the pro-apoptotic genes (Caspase-3, Caspase-8, BAX , and p53 ) with concurrent downregulation of the antiapoptotic mediators (Bcl-2, c- FLIP , and Survivin), and marked proliferative and metastatic drivers suppression, including CDK4, CDK6 , cyclin D1, β-catenin, mTOR , MMP -9, and VEGF, alongside restoration of the CDK inhibitors p21 , p27, and KLF4 and normalization of cGAS, STING, and IRF3 mRNA levels. LIP-MLT/NsCR further best-preserved body weight and colon length, lowered diarrhea and rectal-bleeding scores, restored colonic histopathological architecture, and most strongly diminished the immunoexpression of MMP -9 and VEGF relative to untreated cancer tissues. Taken together, the combined LIP-MLT/NsCR nanoformulation attenuated DMH-induced CRC progression to a greater extent than either monotherapy or conventional 5-FU, supporting the combined melittin–chrysin nanoformulation as a promising, multi-targeted strategy against colorectal cancer.