Lysine-Rich Polypeptide Modulates Forkhead Box O3 and Phosphoinositide 3-Kinase-Protein Kinase B Pathway To Induce Apoptosis in Breast Cancer.

Abstract

The PI3K/AKT/FOXO3 pathway is one of the most frequently involved signaling pathways in cancer, including breast cancer. Therefore, we synthesized a novel lysine-rich polypeptide (Lys-PP) using de novo assembly method and evaluated its anticancer effect. We characterized the structural and physicochemical properties of Lys-PP using various techniques. Later, we used integrated approaches such as in silico, in vitro, and in vivo analysis to confirm the anticancer and therapeutic effect of Lys-PP. First, RNA sequencing suggests Lys-PP disrupted the central carbon metabolic pathway through the modulation of prolactin signaling. Additionally, docking analysis also confirmed the significant association of PI3K/AKT and FOXO3 pathway to induce an apoptotic effect on cancer. Second, Lys-PP exhibited a significant cytotoxicity effect against MDA-MB-231 but no cytotoxic effects on RAW 264.7 and HEK-293, respectively. The cytotoxic effect of Lys-PP-induced apoptosis by an increase in FOXO3a protein expression and a decrease in PI3K/AKT pathway was confirmed by quantitative real-time polymerase chain reaction, immunoblotting, and fluorescent microscopy. Later, immunohistochemistry and hematoxylin and eosin staining on MDA-MD-231 showed increased FOXO3a expression and cell death in the xenograft mice model. Further, liver function, metabolic health, or lipid profile upon Lys-PP showed the absence of significant modulation in the biomarkers except for kidney-related biomarkers. Overall, our comprehensive study provides the first evidence of Lys-PP antibreast cancer action, which could serve as a potential treatment in an alternative or complementary medicine practice.