Therapy-Induced Senescence Drives Bone Loss

Abstract

Chemotherapy is important for cancer treatment, however, toxicities limit its use. While great strides have been made to ameliorate the acute toxicities induced by chemotherapy, long-term comorbidities including bone loss remain a significant problem. Chemotherapy-driven estrogen loss is postulated to drive bone loss, but significant data suggests the existence of an estrogen-independent mechanism of bone loss. Using clinically relevant mouse models, we showed that senescence and its senescence-associated secretory phenotype (SASP) contribute to chemotherapy-induced bone loss that can be rescued by depleting senescent cells. Chemotherapy-induced SASP could be limited by targeting the p38MAPK-MK2 pathway, which resulted in preservation of bone integrity in chemotherapy-treated mice. These results transform our understanding of chemotherapy-induced bone loss by identifying senescent cells as major drivers of bone loss and the p38MAPK–MK2 axis as a putative therapeutic target that can preserve bone and improve a cancer survivor's quality of life. Significance: Senescence drives chemotherapy-induced bone loss that is rescued by p38MAPK or MK2 inhibitors. These findings may lead to treatments for therapy-induced bone loss, significantly increasing quality of life for cancer survivors.

Deconstructing tumor heterogeneity: the stromal perspective

“…In this context, Sheila Stewart discussed her findings related to the impact of senescence in chemotherapy-induced bone loss, a common comorbidity in cancer patients. Using a genetic mouse model, her team found that elimination of senescent cells that arise after chemotherapy prevented bone loss [58]. In addition, targeting SASP pathways using pharmacological inhibition of p38MAPK/MK2 signaling also limited chemotherapy-induced side effects [58].…”

“…Using a genetic mouse model, her team found that elimination of senescent cells that arise after chemotherapy prevented bone loss [58]. In addition, targeting SASP pathways using pharmacological inhibition of p38MAPK/MK2 signaling also limited chemotherapy-induced side effects [58]. Senescence is not only triggered by chemotherapy but occurs normally in healthy individuals, as part of the aging process, and may directly impact tumorigenesis.…”

Emerging Autophagy Functions Shape the Tumor Microenvironment and Play a Role in Cancer Progression - Implications for Cancer Therapy

“…However, studies based on therapy-induced senescence (TIS) indicated the emergence of adverse effects on cancer treatment (95,96). Chemotherapy-induced SASP drives bone loss in breast cancer and its regulation by p38-MAPK-MK2 inhibition could preserve bone, improving the quality of life of patients (97). TIS may contribute to unwanted outcomes through the stimulation of inflammation by increased secretion of SASP factors, the induction of senescence-associated stemness phenotype or senescence cell scape and further proliferation recovery (98-100).…”

The Dynamic Process and Its Dual Effects on Tumors of Therapy-Induced Senescence

“…For example, limiting therapy-induced SASPs by inhibiting the p38 MAPK-MK2 pathway could rescue chemotherapy-induced bone loss in doxorubicin-treated mouse models. 17 Wang et al found that TIS cells became vulnerable to apoptosis induction by ABT263 in vitro, and demonstrated the feasibility of the sequential therapy for cancer in which senotherapy could be administered concomitantly or after senescence-inducing treatment. 25 In preclinical mouse models of ovarian and breast cancer, concurrent PARPi and ABT263 treatment was observed to have a significant potentiation of cell killing.…”