Biology subjects

Golas, A.

Publications and source records attributed to Golas, A..

4 recordsLinked to original sources

bioRxiv2025

Romaciclib, a CDK8/CDK19 inhibitor, can overcome venetoclax resistance through a combinatorial strategy

The combination of venetoclax (VEN) and hypomethylating agents (HMA) is the standard of care in acute myeloid leukemia (AML) for elderly patients unfit for intensive chemotherapy. Despite its clinical success, most patients eventually relapse, creating an urgent need for effective therapeutic alternatives. In this study, we aimed to evaluate the potential of romaciclib, a first-in-class CDK8/CDK19 inhibitor, in combination with VEN to overcome stroma-mediated and primary/acquired VEN-resistance. We assessed the efficacy of RVU120+VEN combination in both sensitive and resistant AML cell lines and primary patient-derived models. Our finding demonstrated that romaciclib synergizes with VEN in AML cell lines and in 8 out of 11 patient-derived cell samples. The proteomic and functional studies demonstrated that combination induced apoptosis through caspase-dependent cleavage of MCL-1. In vivo studies confirmed the efficacy of RVU120+VEN, showing eradication of leukemic cells and bone marrow recovery. Importantly, the combination effectively overcame both stroma-mediated and transcriptionally dependent VEN-resistance. Mechanistic studies, focusing on transcriptomic analyses, identified key resistance-associated pathways, including IL6/JAK/STAT3, TGF-{beta}, PI3K/AKT/MTOR, and inflammatory signaling, being suppressed by combination treatment. Furthermore, an in vivo study using a VEN-resistant patient-derived xenograft (PDX) model confirmed the efficacy of the combination, demonstrating a significant reduction in leukemia burden and a decreased proportion of leukemia initiating cells (LIC) following treatment. These findings prove the highly synergistic mechanism of action of RVU120+VEN combination and the potential to overcome primary/acquired VEN resistance in relapse/refractory AML disease. Altogether, the presented results support ongoing clinical studies evaluating romaciclib and VEN in VEN/HMA-refractory patients (NCT06191263) and provide a basis for future exploration as a frontline therapy in VEN-naive patients.

cancer biology↗

bioRxiv2025

Reference-based chemical-genetic interaction profiling to elucidate small molecule mechanism of action in Mycobacterium tuberculosis

In an era of increasing resistance, new and effective strategies are needed for antibiotic discovery. Whole-cell active screens yield candidate compounds lacking mechanism-of-action (MOA) information and thus do not provide biological insight for prioritization. We previously reported PROSPECT (PRimary screening Of Strains to Prioritize Expanded Chemistry and Targets), an antimicrobial discovery strategy that measures chemical-genetic interactions between small molecules and a pool of Mycobacterium tuberculosis mutants, each depleted of a different essential protein target. PROSPECT facilitates efficient hit prioritization by simultaneously identifying whole-cell active compounds with high sensitivity and providing early insights into their MOA. Here, we report a reference-based approach to infer MOA from often complex PROSPECT data. For this aim, we curated a reference set of 437 compounds with published, annotated MOA and known or suspected antitubercular activity, and applied PROSPECT to it. We then developed Perturbagen CLass (PCL) analysis, a computational method that predicts MOA by comparing chemical-genetic interaction profiles of unknown compounds to those of this reference set. In leave-one-out cross-validation, PCL analysis correctly predicted MOA with 70% sensitivity and 75% precision. When applied to 75 antitubercular leads with known MOA previously reported by GlaxoSmithKline (GSK), PCL analysis similarly achieved 69% sensitivity and 87% precision. We also analyzed 98 GSK compounds lacking MOA information, predicting 60 of them to act via a reference MOA, and followed up with functional validation of 29 compounds predicted to target respiration-related MOAs. Finally, we applied PROSPECT and PCL analysis to [~]5,000 compounds from larger unbiased libraries that had not been preselected for antitubercular activity. PCL analysis identified a novel scaffold lacking wild-type activity but predicted to inhibit respiration via QcrB, and we confirmed this prediction while chemically optimizing this scaffold to achieve wild-type activity. PCL analysis of PROSPECT data thus enables rapid MOA assignment and hit prioritization, advancing the discovery of new, potent antitubercular compounds.

microbiology↗

bioRxiv2024

Multiplexed screen identifies a Pseudomonas aeruginosa-specific small molecule targeting the outer membrane protein OprH and its interaction with LPS

SUMMARYThe surge of antimicrobial resistance threatens efficacy of current antibiotics, particularly against Pseudomonas aeruginosa, a highly resistant gram-negative pathogen. The asymmetric outer membrane (OM) of P. aeruginosa combined with its array of efflux pumps provide a barrier to xenobiotic accumulation, thus making antibiotic discovery challenging. We adapted PROSPECT1, a target-based, whole-cell screening strategy, to discover small molecule probes that kill P. aeruginosa mutants depleted for essential proteins localized at the OM. We identified BRD1401, a small molecule that has specific activity against a P. aeruginosa mutant depleted for the essential lipoprotein, OprL. Genetic and chemical biological studies identified that BRD1401 acts by targeting the OM {beta}-barrel protein OprH to disrupt its interaction with LPS and increase membrane fluidity. Studies with BRD1401 also revealed an interaction between OprL and OprH, directly linking the OM with peptidoglycan. Thus, a whole-cell, multiplexed screen can identify species-specific chemical probes to reveal novel pathogen biology.

microbiology↗

bioRxiv2018

New inhibitors of Mycobacterium tuberculosis identified using systems chemical biology

New antibiotics are needed to combat rising resistance, with new Mycobacterium tuberculosis (Mtb) drugs of highest priority. Conventional whole-cell and biochemical antibiotic screens have failed. We developed a novel strategy termed PROSPECT (PRimary screening Of Strains to Prioritize Expanded Chemistry and Targets) in which we screen compounds against pools of strains depleted for essential bacterial targets. We engineered strains targeting 474 Mtb essential genes and screened pools of 100-150 strains against activity-enriched and unbiased compounds libraries, measuring > 8.5-million chemical-genetic interactions. Primary screens identified >10-fold more hits than screening wild-type Mtb alone, with chemical-genetic interactions providing immediate, direct target insight. We identified > 40 novel compounds targeting DNA gyrase, cell wall, tryptophan, folate biosynthesis, and RNA polymerase, as well as inhibitors of a novel target EfpA. Chemical optimization yielded EfpA inhibitors with potent wild-type activity, thus demonstrating PROSPECTs ability to yield inhibitors against novel targets which would have eluded conventional drug discovery.

microbiology↗