Identification of chemotherapy-induced senescent cells by scRNA-Seq

To identify which bone resident cells senesced in response to chemotherapy, we performed scRNA-Seq on bone marrow depleted of CD45+, CD71+, Ter119+, CD31+ cells. Our scRNA-Seq analysis identified seven clusters in both Veh- and Doxo-treated mice: CAR cells, three fibroblast populations, chondrocytes, endothelial cells, and osteoblasts that were identified based on cell specific markers. Next, we assessed the expression of the senescence markers (p16 and p21), cell proliferation marker (Mki67) and SASP factors (IL6, Spp1, Cstb, Serpine1, Mmp3). As expected, we found a down regulation of Mki67 and upregulation of senescence markers and SASP factors in the Doxo-treated group compared to Veh. we also checked senescence markers across the clusters and found CAR cells undergo senescence and impact bone homeostasis.