From silk waste to cancer therapy: a review of the therapeutic potential and in vitro cytotoxicity of sericin

Abstract

Cancer is a disease characterized by uncontrolled cell growth, often leading to death. The high incidence of cancer has led to continued exploration of potential therapeutics, particularly those derived from natural products. One of the potential natural products is sericin, which has been shown to have anticancer effects against several types of cancer through various in vitro studies. Previous studies generally indicate that sericin's anticancer effects are reflected in its ability to reduce cancer cell viability and induce apoptosis by regulating the expression levels of its related proteins. Studies have suggested that the expression levels of apoptosis-related proteins are known to influence the metastatic potential of cancer cells. Although the specific antimetastatic effects of sericin, an industrial waste by-product, remain largely unexplored, this review comprehensively evaluates its role as an anticancer agent and its underlying cellular mechanisms. Sericin modulates the apoptotic pathway by shifting the Bax/Bcl-2 ratio, specifically through upregulating the pro-apoptotic Bax and suppressing the anti-apoptotic Bcl-2, leading to the sequential activation of pro-caspase-9 and downstream effector caspases. Beyond its established pro-apoptotic activity, we highlight the ability of sericin to restore the apoptotic threshold, which may effectively limit the survival of circulating tumour cells and their capacity to metastasize. Consequently, while sericin offers a promising frontier for future therapeutic investigation, realizing this remarkable potential requires addressing critical experimental gaps, specifically the current lack of dedicated in vitro migration/ invasion assays and in vivo metastasis models to evaluate sericin impact on disrupting the metastatic cascade.