SSK1, a senescence-specific killing compound, is a β-galactosidase-targeted prodrug attenuates inflammation. SSK1 is activated by lysosomal β-galactosidase and selectively killed senescent cells through the activation of p38 MAPK and induction of apoptosis[1].

SSK1 (0.5 µM; 12-72 hours) activates the phosphorylation levels of both p38 MAPK and MKK3/MKK6 in senescent cells. SSK1 kills senescent cells through the activation of the p38 MAPK signaling pathway. SSK1 is able to induce mitochondrial DNA damage in senescent cells[1]. SSK1 (0.01-1 µM; 3 days) selectively and potently eliminates β-galactosidase-positive senescent cells within a wide therapeutic window[1].

SSK1 (0.5 mg/kg; i.p.; two days every week; for four weeks) could eliminate senescent cells and decrease senescence-associated markers in lung-injured mice[1].In aged mice (20-month-old), SSK1 (0.5 mg/kg; 3 days every 2 weeks for 8 weeks) effectively clears senescent cells in different tissues, decreases the senescence- and age-associated gene signatures, attenuates low-grade local and systemic inflammation, and restores physical function[1].

[1]. Yusheng Cai, et al. Elimination of senescent cells by β-galactosidase-targeted prodrug attenuates inflammation and restores physical function in aged mice. Cell Res. 2020 Jul;30(7):574-589.