Identification and Analysis of Anticancer Therapeutic Targets from the Polysaccharides PSK and PSP Using Inverse Docking

The natural compounds PSK and PSP have antitumor and immunostimulant properties. These pharmacological benefits have been documented in vitro and in vivo, although there is not information in silico which describes the action mechanisms at molecular level. In this study, the inverse docking method was used to identify the interactions of PSK and PSP with two local databases: BPAT with 66 antitumor proteins, and BPSIC with 138 surfaces and intracellular proteins. This led to the identification interactions and coincidences of PSK and AB680 inhibitor in the active site of CD73. It was also found that PSK bonds to CD59 interacting with amino acids APS22 and PHE23, which coincide with the rlLYd4 internalization inhibitor. With the isoform of K-RAS protein, PSK bonded to the TYR32 amino acid at switch 1, while with BAK it bonded to the region of the α1 helix, while PSP bonded to the activation site and the C-terminal and N-terminal ends of that helix. In Bcl-2, PSK interacted at the binding site of the Venetoclax inhibitor, showing coincidences with amino acids ASP111, VAL133, LEU137, MET115, PHE112, and TYR108; while PSP had coincidences with THR132, VAL133, LEU137, GLN118, MET115, APS111, PHE112, and PHE104.