Human papillomavirus-16 E6-positive cervical cancer attenuated by potent 2-(4-biphenylyl)-N-(1-ethyl-4-piperidinyl) acetamide second-generation analogs with improved binding affinity.

Abstract

Human papillomavirus (HPV) infection, particularly HPV16, is a major contributor to the development of cervical cancer. Given the urgent need for novel therapeutic strategies targeting HPV-associated cancers, this study focuses on characterizing second-generation analogs of a lead compound, as a potential inhibitor of HPV16-E6. Protein-ligand docking, Gibbs binding free energy estimation, and molecular dynamics simulations were conducted. HPV16-infected SiHa and CaSki cell lines were used. MTT (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) assay for proliferation and flow cytometry for target inhibition and apoptosis were employed. Computational and cell proliferation analyses revealed that modifications to E6-855, particularly in the piperidinyl group, enhanced binding affinities against HPV16-E6, with E6-272 demonstrating superior binding properties. Molecular dynamics simulations confirmed the stable binding of E6-272 to HPV16-E6, supported by favorable binding energy estimates. E6-272 inhibited the proliferation of SiHa and CaSki cells with GI₅₀ values of 32.56 and 62.09 nM, respectively. The compound reduced HPV16-E6-positive population, while inducing the early and late phase apoptosis in these cells. Structural alterations at the piperidinyl group of E6-855 identified E6-272 as a promising inhibitor of HPV16-E6 with improved efficacy against HPV16-E6. Further experimental validation of E6-272 and its analogs warrant to advance its clinical utility in combating HPV-associated cancers.