Sericin-chitosan conjugated silver nanoparticles protect against 1,2-dimethylhydrazine-induced colon cancer in mice by regulating metastatic biomarkers, prohibiting dysplasia and enhancing antioxidant potential.

Colon cancer is reported as third most prevalent malignancy worldwide, while sericin being an antioxidant, is now used in biomedical applications due to its biochemical characteristics and has shown potential efficacy to treat colon cancer. Sericin was isolated by the degumming process followed by the characterization by using FTIR, UV, XRD, and SEM techniques to confirm the successful synthesis of SAgNPs and SChiAgNPs. The male Balb C mice were then divided into 13 groups. Group 1: Control, Group 2: DMH (20 mg/kg) (injected (IP) thrice a week for 14 weeks). Groups 3,4,5: Sericin (S) (100 mg/kg), Sericin silver nanoparticles (SAgNPs) (100 mg/kg), and Sericin Chitosan silver nanoparticles (SChiAgNPs) (100 mg/kg) were given orally for 14 weeks respectively. Groups 6,7,8,9 were considered as preventive groups and were given DMH (IP) + 5-FU (IP), DMH(IP) + S (orally), DMH (IP) + SAgNPs (orally), DMH (IP) + SChiAgNPs (orally) respectively for the period of 14 weeks Groups 10,11,12,13 were considered as treatment groups and were given 5-FU (5 mg/kg) (IP), (S) (100 mg/kg) (orally), (SAgNPs) (100 mg/kg) (orally), (SChiAgNPs) (100 mg/kg) (orally) for a period of first 7 weeks after 7 weeks of DMH administration (IP). After 14 weeks period study, blood samples and colon tissue were used for the analysis of biochemical markers i.e., CEA, CA19-9, TIMP-1, and IL-6, IL-8, IL-27, SOD, CAT, GR, GSH, GST, MDA and MMP-7 via ELISA and histopathological analysis. The UV absorption peaks obtained at 435 and 463 nm indicated the formation of SAgNPs and SChiAgNPs formation respectively. FTIR spectra peaks obtained, indicate NH stretching of primary and secondary amine group), (NH stretching of amine salt) (N=C=S stretching of thiocyanate compound), (CC stretching of alkene), (NO stretching of nitro compound), (SO stretching of sulfonyl chloride), (CN stretching of amine) and (C-O-O stretching) for sericin, SAgNPs, and SChiAgNPs, confirming, the presence of theses functional groups. The XRD pattern revealed that SAgNPs and SChiAgNPs had structure crystalline structures. EDX characterization peaks for SAgNPs indicated the presence of silver along with other elements including; calcium, oxygen carbon, while EDX characterization peaks for SChiAgNPs indicated the presence of silver along with other elements including; oxygen, carbon, sodium, phosphorus, Sulphur and chlorine. SEM analysis showed that SAgNPs are of spherical shape, while the SChiAgNPs displayed the rectangular shape. The results for biomarker analysis indicated significantly elevated levels of CEA, CA19-9, TIMP-1, IL-6, IL-8, IL-27, MDA, and MMP-7 in DMH treated group (p ≤ 0.001) which were decreased significantly in SChiAg(T) (p ≤ 0.001). In contrast, levels of SOD, GR, GSH, CAT and GST were reduced significantly in DMH treated group, which were increased significantly in SChiAg(T) (p ≤ 0.001). The histopathological analysis of proximal and distal parts of colon tissue of the DMH-treated group showed low-grade dysplasia (LGD), and high-grade dysplasia (HGD) while SChiAgNPs improved the histopathological changes induced by DMH. The findings suggest that Sericin Chitosan conjugated silver nanoparticles showed their efficacy against DMH-induced colon cancer, making a potential future in the anticancer research field.