Naskar, D. | Search bioRxiv

bioRxiv2023

Apigenin exerts anti-cancer effects in colon cancer possibly by regulating Heat shock protein 90 alpha family class A member 1 (HSP90AA1)

Apigenin, a natural flavonoid, has shown early promise in colon cancer (CC); thus, exploring potential mechanisms of apigenin in CC is obligatory. In this study, shared targets of apigenin and CC were identified through different online tools and subjected to functional enrichment analyses like Gene Ontology and KEGG. Further, the protein-protein interaction network of the shared targets was developed (via STRING); hub/core targets were identified (MCODE application). The top targets of apigenin in CC were identified by molecular docking; further investigated for differential gene and protein expression in CC and their influence on CC patient survival (using TCGA data). Based on the docking score of the 13 hub genes, the top 3 targets (HSP90AA1, MMP9, PTGS2) were selected, and their expression was significantly elevated and related to poor overall survival in CC (except PTGS2). Molecular dynamics simulation further validated protein-ligand interactions and selected HSP90AA1 as the best target of apigenin in CC. Finally, apigenin was found to be involved in the cytotoxicity of CC cells (COLO-205) by reducing HSP90AA1 expression. The results of this study identified HSP90AA1 as one of the prime targets of apigenin in CC, and apigenin might act on HSP90AA1 to exert its anti-cancer mechanism.

cancer biology↗

bioRxiv2022

The structure of a Plasmodium vivax Tryptophan Rich Antigen suggests a lipid binding function for a pan-Plasmodium multi-gene family

Tryptophan Rich Antigens (TRAgs) are encoded by a multi-gene family in all Plasmodium species, significantly expanded in P. vivax, but their function is not currently known. We show that multiple P. vivax TRAgs are expressed on the merozoite surface and that one, PVP01_0000100 binds red blood cells with a strong preference for reticulocytes. Solving the structure of the C-terminal tryptophan rich domain that defines the TRAg family revealed a three-helical bundle that is conserved across Plasmodium and has homology with lipid-binding BAR domains involved in membrane remodelling. Biochemical assays confirmed that this domain has lipid binding activity with preference for sulfatide, a glycosphingolipid present in the outer leaflet of plasma membranes. Deletion of the putative orthologue in P. knowlesi, PKNH_1300500, impacts invasion in reticulocytes, suggesting a role for membrane remodelling during this essential process. Together, this work suggests a molecular function for the TRAg family for the first time.

microbiology↗