Development of gene set for Rb inactivation signature in spherogenesis

We found that Rb inactivation induces sphere-forming activity in primary soft tissue sarcoma cells derived from p53 null mice. To elucidate molecular mechanism, we employed RNA-sequence as a discovery platform to identify Rb inactivation signature in spherogenesis. We hypothesized that upregulated genes subtracted in Non-sensitive cells (No spherogenesis by Rb depletion) from in Sensitive cells (Spherogenesis by Rb depletion) contribute to induction of sphere-formation , and a 53-gene signature upregulated by Rb depletion specifically in sensitive clones was identified. This gene set was highly enriched in genes involved in inflammation. These data revealed that activation of inflammatory signaling contribute to Rb-depletion induced sphere formation.