Anti-breast cancer drugs targeting cell-surface glucose-regulated protein 78: a drug repositioning study.

Breast cancer (BC) is prevalent worldwide and is a leading cause of death among women. However, cell-surface glucose-regulated protein 78 (cs-GRP78) is overexpressed in several types of cancer and during pathogen infections. This study examines two well-known BC drugs approved by the FDA as BC treatments to GRP78. The first type consists of inhibitors of cyclin-based kinases 4/6, including abemaciclib, palbociclib, ribociclib, and dinaciclib. In addition, tunicamycin, and doxorubicin, which are among the most effective anticancer drugs for early and late-stage BC, are tested against GRP78. As (-)-epiGallocatechin gallate inhibits GRP78, it is also being evaluated (used as positive control). Thus, using molecular dynamics simulation approaches, this study aims to examine the advantages of targeting GRP78, which represents a promising cancer therapy regime. In light of recent advances in computational drug response prediction models, this study aimed to examine the benefits of GRP78 targeting, which represents a promising cancer therapy regime, by utilizing combined molecular docking and molecular dynamics simulation approaches. The simulated protein (50 ns) was docked with the drugs, then a second round of dynamics simulation was performed for 100 ns. After that, the binding free energies were calculated from 30 to 100 ns for each complex during the simulation period. These findings demonstrate the efficacy of abemaciclib, ribociclib, and tunicamycin in binding to the nucleotide-binding domain of the GRP78, paving the way for elucidating the mode of interactions between these drugs and cancer (and other stressed) cells that overexpress GRP78.Communicated by Ramaswamy H. Sarma.