Senescent Secretome of Blind Mole Rat Inhibits Malignant Behavior of Human Breast Cancer Cells Triggering Bystander Senescence and Targeting Inflammatory Response.

Subterranean blind mole rat, , has developed strategies to withstand cancer by maintaining genome stability and suppressing the inflammatory response. cells undergo senescence without the acquisition of senescence-associated secretory phenotype (SASP) in its canonical form, namely, it lacks the main inflammatory mediators. Since senescence can propagate through paracrine factors, we hypothesize that conditioned medium (CM) from senescent fibroblasts can transmit the senescent phenotype to cancer cells without inducing an inflammatory response, thereby suppressing malignant behavior. To address this issue, we investigated the effect of CMs of senescent fibroblasts on the proliferation, migration, and secretory profile in MDA-MB-231 and MCF-7 human breast cancer cells. The results suggest that CM induced senescence in cancer cells, as evidenced by increased senescence-associated beta-galactosidase (SA-β-Gal) activity, growth suppression and overexpression of senescence-related / genes. Contemporaneously, CM suppressed the secretion of the main inflammatory factors in cancer cells and decreased their migration. In contrast, human CM, while causing a slight increase in SA-β-Gal activity in MDA-MB-231 cells, did not decrease proliferation, inflammatory response, and cancer cell migration. Dysregulation of IL-1α under the influence of CM, especially the decrease in the level of membrane-bound IL1-α, plays an important role in suppressing inflammatory secretion in cancer cells, which in turn leads to inhibition of cancer cell migration. Overcoming of SASP in tumor cells in response to paracrine factors of senescent microenvironment or anti-cancer drugs represents a promising senotherapeutic strategy in cancer treatment.