Project description:Hypermutable P. aeruginosa isolates are prevalent in cystic fibrosis and associated with acute exacerbations of chronic lung infections leading to early death and increased resistance emergence. Achievable epithelial lining fluid concentration-time profiles of meropenem and tobramycin in monotherapy and combination regimens were simulated against two clinical hypermutable P. aeruginosa isolates; CW8 (MICmeropenem=8mg/L, MICtobramycin=8mg/L) and CW44 (MICmeropenem=4mg/L, MICtobramycin=2mg/L) in an 8-day hollow fiber infection model (HFIM). Both isolates were previously characterised with genotypes resembling those of carbapenem- and aminoglycoside-resistant strains. Meropenem at 1 or 2g every 8h (3h infusion) and tobramycin at 5 or 10mg/kg body weight every 24h (0.5h infusion) were studied. Total and resistant bacterial counts were determined. Whole genome sequencing was performed on mutants and whole population samples at 191h, and transcriptomics at 1 and 191h. Mechanism-based modelling of total and resistant populations was informed by the multi-omics analysis. While all regimens against both isolates produced regrowth, the high dose combination synergistically suppressed resistant regrowth against CW8 up to ~96h. The high dose combination provided some killing against CW44, however failed to prevent resistant regrowth. In CW8, mutations emerged during treatment in pmrB, ampR, and multiple efflux pump regulators; in CW44, mutations in pmrB and PBP2 were observed. In CW8, resistance genes mexB and oprM were downregulated by the combination at 1h and coincided with synergistic killing, with differential expression of outer membrane norspermidine and lipopolysaccharide genes at 191h. Mechanism-based modelling incorporating subpopulation and mechanistic synergy successfully characterized the bacterial response of CW8, while mechanistic synergy was not required for CW44. Incorporating information from the multi-omics analyses was instrumental in building the mechanism-based model to describe the bacterial response of the hypermutable isolates, whereas MICs and traditional PK/PD indices could not predict the outcomes of the HFIM.
Project description:Comparison between the multi-drug resistance Salmonella enteric serotype Newport strains from the US and the pan-susceptible strains from the UK
Project description:Acute myeloid leukemia (AML) exhibits a spectrum of responses to chemotherapy, with drug resistance being a significant clinical challenge. This study employs a multi-omics approach, particularly multiplexed single-cell RNA sequencing (scRNA-seq), to characterize the molecular mechanisms underlying drug resistance in AML cells. We identified significant cellular heterogeneity and a dynamic transcriptomic trajectory in AML cells with specific drug treatment, and discovered a reprogramming towards a more stem-like state. Interestingly, Ara-C-resistant KG-1a cells predominantly originated from G2/M subpopulations, indicating a cell cycle-specific resistance mechanism. Our analysis also revealed that epigenetic changes of DNA methylation and chromatin architechture, and altered transcription factor activities were implicated in rapid Ara-C resistance, whereas exomic mutations did not significantly contribute to it. We suggest both intrinsic and acquired resistance mechanisms act together and build a resultant force that aids AML cells in evading therapeutic interventions. The multidimensional changes observed post-treatment showed a complex interplay in the development of drug resistance. This study provides a cellular and molecular portrait of drug response and resistance in AML, offering potential therapeutic targets and a foundation for future research aimed at overcoming chemoresistance.
Project description:Acute myeloid leukemia (AML) exhibits a spectrum of responses to chemotherapy, with drug resistance being a significant clinical challenge. This study employs a multi-omics approach, particularly multiplexed single-cell RNA sequencing (scRNA-seq), to characterize the molecular mechanisms underlying drug resistance in AML cells. We identified significant cellular heterogeneity and a dynamic transcriptomic trajectory in AML cells with specific drug treatment, and discovered a reprogramming towards a more stem-like state. Interestingly, Ara-C-resistant KG-1a cells predominantly originated from G2/M subpopulations, indicating a cell cycle-specific resistance mechanism. Our analysis also revealed that epigenetic changes of DNA methylation and chromatin architechture, and altered transcription factor activities were implicated in rapid Ara-C resistance, whereas exomic mutations did not significantly contribute to it. We suggest both intrinsic and acquired resistance mechanisms act together and build a resultant force that aids AML cells in evading therapeutic interventions. The multidimensional changes observed post-treatment showed a complex interplay in the development of drug resistance. This study provides a cellular and molecular portrait of drug response and resistance in AML, offering potential therapeutic targets and a foundation for future research aimed at overcoming chemoresistance.
Project description:Tumor heterogeneity and therapy resistance are hallmarks of pancreatic ductal adenocarcinoma (PDAC). Emerging evidence supports treatment-induced resistance to be a multifactorial process mediated by cellular plasticity involving epigenetic regulation. Here, we used a multi-omics approach to analyze in detail molecular mechanisms underlying MEK inhibitor (MEKi) resistance. Therefore, we characterized different cell stages (parental, MEKi resistant, reverted after different passages of drug withdrawal) in primary cell lines derived from a genetic PDAC mouse model, thereby minimizing inter-individual heterogeneity that could distort genome-wide analyses.