Biology subjects

Wise, J. G.

Publications and source records attributed to Wise, J. G..

3 recordsLinked to original sources

bioRxiv2024

Iterative in silico identification of P-glycoprotein inhibitors

Overexpression of the polyspecific efflux transporter, P-glycoprotein (P-gp, MDR1, ABCB1), is a major mechanism by which cancer cells acquire multidrug resistance (MDR), the resistance to diverse chemotherapeutic drugs. Inhibiting drug transport by P-gp can resensitize cancer cells to chemotherapy, but there are no P-gp inhibitors available to patients. Clinically unsuccessful P-gp inhibitors tend to bind at the pumps transmembrane drug binding domains and are often P-gp transport substrates, resulting in lowered intracellular concentration of the drug and altered pharmacokinetics. In prior work, we used computationally accelerated drug discovery to identify novel P-gp inhibitors that target the pumps cytoplasmic nucleotide binding domains. Our first-draft study provided conclusive evidence that the nucleotide binding domains of P-gp are viable targets for drug discovery. Here we develop an enhanced, computationally accelerated drug discovery pipeline that expands upon our prior work by iteratively screening compounds against multiple conformations of P-gp with molecular docking. Targeted molecular dynamics simulations with our homology model of human P-gp were used to generate docking receptors in conformations mimicking a putative drug transport cycle. We offset the increased computational complexity using custom Tanimoto chemical datasets, which maximize the chemical diversity of ligands screened by docking. Using our expanded, virtual-assisted pipeline, we identified nine novel P-gp inhibitors that reverse MDR in two types of P-gp overexpressing human cancer cell lines, reflecting a 13.4% hit rate. Of these inhibitors, all were non-toxic to non-cancerous human cells, and six were not likely to be transport substrates of P-gp. Our novel P-gp inhibitors are chemically diverse and are good candidates for lead optimization. Our results demonstrate that the nucleotide binding domains of P-gp are an underappreciated target in the effort to reverse P-gp-mediated multidrug resistance in cancer.

cancer biology↗

bioRxiv2021

Transport Dynamics of MtrD: an RND multidrug efflux pump from Neisseria gonorrhoeae

The MtrCDE system confers multidrug resistance to Neisseria gonorrhoeae, the causative agent of gonorrhea. Using free and directed Molecular Dynamics (MD) simulations, we analyzed the interactions between MtrD and Azithromycin, a transport substrate of MtrD and a last-resort clinical treatment for multidrug resistant gonorrhea. We then simulated the interactions between MtrD and Streptomycin, an apparent non-substrate of MtrD. Using known conformations of MtrD homologues, we simulated a potential dynamic transport cycle of MtrD using Targeted MD techniques (TMD), and we note that forces were not applied to ligands of interest. In these TMD simulations, we observed the transport of Azithromycin and the rejection of Streptomycin. In an unbiased, long-timescale simulation of AZY-bound MtrD, we observed the spontaneous diffusion of Azithromycin through the periplasmic cleft. Our simulations show how the peristaltic motions of the periplasmic cleft facilitate the transport of substrates by MtrD. Our data also suggest that multiple transport pathways for macrolides may exist within the periplasmic cleft of MtrD.

biochemistry↗

bioRxiv2020

Transport of Alzheimer's Associated Amyloid-β Catalyzed by P-glycoprotein

P-glycoprotein (P-gp) is a critical membrane transporter in the blood brain barrier (BBB) and is implicated in Alzheimers disease (AD). However, previous studies on the ability of P-gp to directly transport the Alzheimers associated amyloid-{beta} (A{beta}) protein have produced contradictory results. Here we use molecular dynamics (MD) simulations, transport substrate accumulation studies in cell culture, and biochemical activity assays to show that P-gp actively transports A{beta}. We observed transport of A{beta}40 and A{beta}42 monomers by P-gp in explicit MD simulations of a putative catalytic cycle. In in vitro assays with P-gp overexpressing cells, we observed enhanced accumulation of fluorescently labeled A{beta}42 in the presence of Tariquidar, a potent P-gp inhibitor. We also showed that A{beta}42 stimulated the ATP hydrolysis activity of isolated P-gp in nanodiscs. Our findings expand the substrate profile of P-gp, and suggest that P-gp may contribute to the onset and progression of AD.

biochemistry↗