Background: Cell senescence, a state of cell cycle arrest, is primarily induced by the p53/p21 pathway in response to DNA damage, often from therapeutic interventions. P21 plays a crucial role, with its expression unfolding in two phases during DNA damage: an initial response within hours and a subsequent delayed response leading to senescence. Our research focuses on a new strategy for Ovarian cancer consisting in inducing senescence of cancer cells and then kill senescent cells by specific drug called senolytics.

In a prior study, we successfully applied this strategy to High-Grade Serous Carcinoma in mice. Our current project aims to adapt and implement this strategy in Clear Cell Carcinoma.

Methods: Senescence monitoring involved a reporter named p21SEN derived from the p21 promoter. This reporter exclusively displayed specific activation during the senescence phase.

Results: Characterizing senescence began with investigating p21SEN regulation. P21SEN activation appears independent of p53 expression but is dependent on NF-kB activity and repressed by SP1 expression. Moreover, we showed that p21SEN-positive cell are sensitive to senolytic

Next, p21SEN was employed for in vivo monitoring and targeting of cell senescence by fusing it with a three-modality reporter (3MR). This allowed tracking senescence via bioluminescence for in vivo studies and fluorescence for in vitro experiments. Additionally, p21SEN-positive cells can be eliminated through Ganciclovir treatment. Successful validation in vitro has led to ongoing experiments focusing on in vivo applications.

Conclusion: Our study illuminates p21SEN's senescence-specific activity, revealing its regulation through the NF-kB and SP1 while independent from p53. We demonstrate that p21SEN-positive senescent cells are targetable by senolytics in vitro. The ultimate goal is to harness the p21SEN reporter's potential in vivo to test our innovative strategy for inducing and eliminating senescence in Clear Cell Carcinoma.