Project description:Knowledge of the genetic mechanisms underlying among-individual variation in response to environmental variables or treatment is important in many research areas; for example, acquaintance of the set of causal genetic variants for drug responses could revolutionize the field of personalized medicine. We used Drosophila melanogaster to investigate the genetic signature underlying variability in response to methylphenidate (MPH), a drug used in treatment of ADHD. We exposed a wild type D. melanogaster population to MPH or a control treatment and observed an increase in locomotor activity in individuals exposed to MPH. Whole-genome transcriptomic analyses revealed that the behavioral response to MPH was associated with abundant gene expression alterations. To confirm these patterns in a different genetic background, and to further advance knowledge on the genetic signature of drug response variability, we used a system of sequenced inbred lines, the Drosophila Genetic Reference Panel. Utilizing an integrative genomic approach we incorporated the transcriptomic data as well as gene interactions into the genomic analyses, from which we identified putative candidate genes for drug response variability. We successfully validated 70% of the investigated putative candidate genes by gene expression knockdown. Furthermore, we showed that MPH has cross generational behavioral- and transcriptomic effects.
Project description:Therapies targeting signaling molecules mutated in cancers can often have striking short-term effects, but the emergence of resistant cancer cells is a major barrier to full cures. Resistance can sometimes result from a secondary mutations in rare cells, but other times, there is no clear genetic cause, raising leaving the possibility of non-genetic rare cell variability. Here, we show that melanoma cells can display profound transcriptional variability at the single cell level that predicts which cells will ultimately resist drug treatment. This variability involves semi-coordinated transcription of a number of resistance markers at high levels in a very small percentage of cells. The addition of drug then induces an epigenetic reprogramming in these cells, converting the transient transcriptional state to a stably resistant state. This reprogramming begins with a progressive process consisting of a loss of SOX10-mediated differentiation followed by activation of new signaling pathways, partially mediated by activity of Jun-AP-1 and TEAD. Our work reveals the multistage nature of the acquisition of drug resistance and provides a framework for understanding resistance dynamics. We find that other cell types also exhibit sporadic expression of many of these same marker genes, suggesting the existence of a general rare-cell expression program.
Project description:Therapies targeting signaling molecules mutated in cancers can often have striking short-term effects, but the emergence of resistant cancer cells is a major barrier to full cures. Resistance can sometimes result from a secondary mutations in rare cells, but other times, there is no clear genetic cause, raising leaving the possibility of non-genetic rare cell variability. Here, we show that melanoma cells can display profound transcriptional variability at the single cell level that predicts which cells will ultimately resist drug treatment. This variability involves semi-coordinated transcription of a number of resistance markers at high levels in a very small percentage of cells. The addition of drug then induces an epigenetic reprogramming in these cells, converting the transient transcriptional state to a stably resistant state. This reprogramming begins withis a progressive process consisting of a loss of SOX10-mediated differentiation followed by activation of new signaling pathways, partially mediated by activity of Jun-AP-1 and TEAD. Our work reveals the multistage nature of the acquisition of drug resistance and provides a framework for understanding resistance dynamics. We find that other cell types also exhibit sporadic expression of many of these same marker genes, suggesting the existence of a general rare-cell expression program.
Project description:Thermal acclimation study on Drosophila melanogaster reared at 3 different temperatures (12, 25, and 31oC). The proteomic profiles of D. melanogaster under these different temperatures were analyzed and compared using label-free tandem mass spectrometry.