A study published in Nature (2017) reveals that melanoma cells exhibit significant transcriptional variability at the single-cell level, which predicts resistance to cancer drugs. This variability involves infrequent, semi-coordinated transcription of resistance markers in a small percentage of cells. Drug treatment induces epigenetic reprogramming, converting transient transcriptional states into stable resistance. This process begins with loss of SOX10-mediated differentiation and activation of new signaling pathways, including Jun-AP-1 and TEAD. The study shows that resistance arises in two phases: first, rare cells become transiently pre-resistant, then drug treatment initiates reprogramming to a stable resistant state. The research highlights that resistance can occur through non-genetic rare cell variability, not just genetic mutations. Single-cell gene expression differences mark pre-resistant cells, and high expression of resistance markers like EGFR, WNT5A, AXL, EGFR, PDGFRβ, and JUN is associated with resistance. High-throughput single molecule RNA FISH revealed that rare cells express resistance genes at high levels before drug exposure. After treatment, these cells express these markers at more uniform levels, indicating stable resistance. The study also found that sporadic expression of resistance markers is widespread across various cell types, including melanocytes and other cancers. This suggests a general rare-cell expression program involved in resistance and potential phenotype switching. The findings indicate that resistance markers are often co-expressed, with high odds ratios between resistance genes, indicating co-expression. The study further shows that resistance markers are not clustered but may form network structures. The research also demonstrates that drug "holidays" do not affect the transcriptome or resistant phenotype, showing that the resistant state is stable. The study confirms that resistance arises through a transient pre-resistant state, not heritable mutations. The findings suggest that resistance can be managed through interval dosing strategies, as transient effects may allow some cells to survive until secondary mutations occur. The study used various methods, including Luria-Delbrück fluctuation analysis, RNA FISH, and ATAC sequencing, to analyze resistance mechanisms. These methods revealed that resistance involves epigenetic reprogramming and changes in transcription factor occupancy. The study also identified mutations in various genes, but no new mutations were found in resistant subclones, suggesting that resistance is not due to genetic mutations but rather to rare cell variability and epigenetic changes. The findings have implications for therapeutic targeting, including lipid peroxidase pathways.A study published in Nature (2017) reveals that melanoma cells exhibit significant transcriptional variability at the single-cell level, which predicts resistance to cancer drugs. This variability involves infrequent, semi-coordinated transcription of resistance markers in a small percentage of cells. Drug treatment induces epigenetic reprogramming, converting transient transcriptional states into stable resistance. This process begins with loss of SOX10-mediated differentiation and activation of new signaling pathways, including Jun-AP-1 and TEAD. The study shows that resistance arises in two phases: first, rare cells become transiently pre-resistant, then drug treatment initiates reprogramming to a stable resistant state. The research highlights that resistance can occur through non-genetic rare cell variability, not just genetic mutations. Single-cell gene expression differences mark pre-resistant cells, and high expression of resistance markers like EGFR, WNT5A, AXL, EGFR, PDGFRβ, and JUN is associated with resistance. High-throughput single molecule RNA FISH revealed that rare cells express resistance genes at high levels before drug exposure. After treatment, these cells express these markers at more uniform levels, indicating stable resistance. The study also found that sporadic expression of resistance markers is widespread across various cell types, including melanocytes and other cancers. This suggests a general rare-cell expression program involved in resistance and potential phenotype switching. The findings indicate that resistance markers are often co-expressed, with high odds ratios between resistance genes, indicating co-expression. The study further shows that resistance markers are not clustered but may form network structures. The research also demonstrates that drug "holidays" do not affect the transcriptome or resistant phenotype, showing that the resistant state is stable. The study confirms that resistance arises through a transient pre-resistant state, not heritable mutations. The findings suggest that resistance can be managed through interval dosing strategies, as transient effects may allow some cells to survive until secondary mutations occur. The study used various methods, including Luria-Delbrück fluctuation analysis, RNA FISH, and ATAC sequencing, to analyze resistance mechanisms. These methods revealed that resistance involves epigenetic reprogramming and changes in transcription factor occupancy. The study also identified mutations in various genes, but no new mutations were found in resistant subclones, suggesting that resistance is not due to genetic mutations but rather to rare cell variability and epigenetic changes. The findings have implications for therapeutic targeting, including lipid peroxidase pathways.