Project description:Chemotherapy resistance is a major obstacle to curing cancer patients. Combination drug regimens have shown promise as a method to overcome resistance; however, to date only some cancers have been cured with this method. Collateral sensitivity – the phenomenon whereby resistance to one drug is co-occurrent with sensitivity to a second drug – has been gaining traction as a promising new concept to guide rational design of combination regimens. Here we evolved over 100 subclones of the Eµ-Myc; p19ARF -/- cell line to be resistant to one of four classical chemotherapy agents: doxorubicin, vincristine, paclitaxel, and cisplatin. We then surveyed collateral responses to acquisition of resistance to these agents. Although numerous collateral sensitivities have been documented for antibiotics and targeted cancer therapies, we observed only one collateral sensitivity: half of cell lines that acquired resistance to paclitaxel also acquired a collateral sensitivity to verapamil. However, we found that the mechanism of this collateral sensitivity was unrelated to the mechanism of paclitaxel resistance. Interestingly, we observed heterogeneity in the phenotypic response to acquisition of resistance to most of the drugs we tested, most notably for paclitaxel, suggesting the existence of multiple different states of resistance. Surprisingly, this phenotypic heterogeneity in paclitaxel resistant cell lines was unrelated to transcriptomic heterogeneity among those cell lines. These features of phenotypic and transcriptomic heterogeneity must be taken into account in future studies of treated tumor subclones and in design of chemotherapy combinations.
Project description:Broad-spectrum multi-target tyrosine kinase inhibitors (mTKIs) are clinically approved for the treatment of soft tissue sarcomas (STS). However, acquired resistance inevitably arises in the majority of STS patients. There is therefore an urgent need to identify new strategies to overcome resistance and achieve durable treatment responses. Here we show that STS cells that acquire resistance to clinically relevant mTKIs are cross-resistant to one another and sequential treatment does not delay the acquisition of drug resistance. Instead, we find that en route to acquiring drug resistance, STS cells develop collateral sensitivities to alternative drugs. We demonstrate that the mTKI sitravatinib rapidly induces collateral sensitivity to the FGFR inhibitor infigratinib which can be exploited for adaptive therapy to suppress STS cell growth. This study provides proof-of-principle that collateral sensitivity may be an effective strategy for overcoming resistance to mTKIs and this novel approach should be explored in the design of future trials.
Project description:Chronic Pseudomonas aeruginosa infections evades antibiotic therapy and are associated with mortality in cystic fibrosis (CF) patients. We find that in vitro resistance evolution of P.aeruginosa towards clinically relevant antibiotics leads to phenotypic convergence towards distinct states. These states are associated with collateral sensitivity towards several antibiotic classes and encoded by mutations in antibiotic resistance genes, including transcriptional regulator nfxB. Longitudinal analysis of isolates from CF patients reveals similar and defined phenotypic states, which are associated with extinction of specific sub-lineages in patients. In depth investigation of chronic P.aeruginosa populations in a CF patient during antibiotic therapy revealed dramatic genotypic and phenotypic convergence. Notably, fluoroquinolone-resistant subpopulations harboring nfxB mutations were eradicated by antibiotic therapy as predicted by our in vitro data. This study supports the hypothesis that antibiotic treatment of chronic infections can be optimized by targeting phenotypic states associated with specific mutations to improve treatment success in chronic infections.
Project description:Cationic antimicrobial peptides (CAPs) are promising novel alternatives to conventional antibacterial agents, but the overlap in resistance mechanisms between small-molecule antibiotics and CAPs is unknown. Does evolution of antibiotic resistance decrease (cross-resistance) or increase (collateral sensitivity) susceptibility to CAPs? We systematically addressed this issue by studying the susceptibilities of a comprehensive set of antibiotic resistant Escherichia coli strains towards 24 antimicrobial peptides. Strikingly, antibiotic resistant bacteria frequently showed collateral sensitivity to CAPs, while cross-resistance was relatively rare. We identified clinically relevant multidrug resistance mutations that simultaneously elevate susceptibility to certain CAPs. Transcriptome and chemogenomic analysis revealed that such mutations frequently alter the lipopolysaccharide composition of the outer cell membrane and thereby increase the killing efficiency of membrane-interacting antimicrobial peptides. Furthermore, we identified CAP-antibiotic combinations that rescue the activity of existing antibiotics and slow down the evolution of resistance to antibiotics. Our work provides a proof of principle for the development of peptide based antibiotic adjuvants that enhance antibiotic action and block evolution of resistance.
Project description:Drug resistance is a major hurdle for the efficacy of cancer therapies. Protein arginine methyltransferase 5 (PRMT5) is an epigenetic regulator that is upregulated in most tumor types, and PRMT5 inhibitors (PRMT5i) are now in clinical trials. Here we describe the first model of resistance to PRMT5 inhibition, using cell lines derived from murine Kras-G12D;p53-null lung adenocarcinomas (LUAD). Initially, PRMT5 inhibition induced proliferation defects and apoptosis, but eventually we were able to generate numerous independent PRMT5i resistant lines. Resistance was drug-induced, not preexisting, and reflects a novel, shared transcriptional state. This state is stable, and it creates a collateral sensitivity to the taxane, paclitaxel. Accordingly, PRMT5i and paclitaxel synergistically suppress Kras-G12D;p53-null murine LUAD cells. Remarkably, a single gene Stathmin 2 (Stmn2) is required for both PRMT5i resistance and paclitaxel sensitivity. Finally, analysis of TCGA patient data showed that high Stmn2 levels correlates with good tumor responses to taxane treatment.
Project description:In this work we describe a robust fosfomycin collateral sensitivity phenotype of Pseudomonas aeruginosa resistant mutants selected by antibiotics from different structural families. The underlying mechanism was the reduced expression of the genes encoding the peptidoglycan-recycling pathway, which preserves the peptidoglycan synthesis in situations where the de novo synthesis is blocked, and of fosA, encoding a fosfomycin-inactivating enzyme.