Therapy Induced Senescence (TIS) leads to sustained growth arrest of cancer cells. Conversely, the Senescence Associated Secretory Phenotype (SASP) has been shown to promote tumorigenesis and metastasis. The associated cytostasis, which was first conceived as permanent, has since been shown to be reversible. Cells escaping senescence further enhance the aggressiveness of cancers. Despite all this, the mechanisms by which cancer cells escape senescence are poorly understood and the development of specific and efficient 'senolytics', specifically targeting senescent cancer cells, is in its infancy. Together with targeted therapeutics, senolytics constitute a promising avenue for improved cancer treatments. Understanding how cancer cells evade senescence is needed to optimize the clinical benefits of this promising approach. Here we characterized the response of three different NRAS mutant melanoma cell lines to a combination of CDK4/6 and MEK inhibitors over 33 days. Transcriptomic data show that all cell lines trigger a senescence program coupled with strong induction of interferons. Kinome profiling revealed the activation of Receptor Tyrosine Kinases (RTKs) and enriched downstream signaling of neurotrophin, ErbB and insulin pathways. Characterization of the miRNA interactome associates miR-211-5p with resistant phenotypes. Finally, integration of bulk and single-cell RNA-seq data identified biological processes perturbed during senescence establishment and escape, and predicts new genes involved in this shift. Overall, our data associate insulin signaling with persistence of a senescent phenotype and suggest a new role for interferon gamma in senescence escape through the induction of EMT and the activation of ERK5 signaling.

Therapy Induced Senescence (TIS) leads to sustained growth arrest of cancer cells. The associated cytostasis has been shown to be reversible and cells escaping senescence further enhance the aggressiveness of cancers. Chemicals specifically targeting senescent cells, so-called senolytics, constitute a promising avenue for improved cancer treatment in combination with targeted therapies. Understanding how cancer cells evade senescence is needed to optimise the clinical benefits of this therapeutic approach. Here we characterised the response of three different NRAS mutant melanoma cell lines to a combination of CDK4/6 and MEK inhibitors over 33 days. Transcriptomic data show that all cell lines trigger a senescence programme coupled with strong induction of interferons. Kinome profiling revealed the activation of Receptor Tyrosine Kinases (RTKs) and enriched downstream signaling of neurotrophin, ErbB and insulin pathways. Characterisation of the miRNA interactome associates miR-211-5p with resistant phenotypes. Finally, iCell-based integration of bulk and single-cell RNA-seq data identifies biological processes perturbed during senescence and predicts 90 new genes involved in its escape. Overall, our data associate insulin signaling with persistence of a senescent phenotype and suggest a new role for interferon gamma in senescence escape through the induction of EMT and the activation of ERK5 signaling.