CDK4/6-inhibiting drug substitutes for p21 and p16 in senescence: duration of cell cycle arrest and MTOR activity determine geroconversion.
CDKN1A (p21) and CDKN2A (p16) inhibit CDK4/6, initiating senescence. According to our view on senescence, the role of p21 and p16 is to cause cell cycle arrest, whereas MTOR (mechanistic target of rapamycin) drives geroconversion to senescence. Recently we demonstrated that one of the markers of p21- and p16-initiated senescence is MEK-dependent hyper-elevation of cyclin D1. We noticed that a synthetic inhibitor of CDK 4/6 (PD0332991) also induced cyclin D1-positive senescence. We demonstrated that PD0332991 and p21 caused almost identical senescence phenotypes. p21, p16, and PD0332991 do not inhibit MTOR, and rapamycin decelerates geroconversion caused by all 3 molecules. Like p21, PD0332991 initiated senescence at any concentration that inhibited cell proliferation. This confirms the notion that a mere arrest in the presence of active MTOR may lead to senescence.
['Leontieva|Olga V|OV|', 'Blagosklonny|Mikhail V|MV|']
D002070:Butadienes D059447:Cell Cycle Checkpoints D045744:Cell Line, Tumor D049109:Cell Proliferation D016922:Cellular Senescence D019938:Cyclin D1 D051358:Cyclin-Dependent Kinase 4 D051361:Cyclin-Dependent Kinase 6 D019941:Cyclin-Dependent Kinase Inhibitor p16 D050759:Cyclin-Dependent Kinase Inhibitor p21 D006801:Humans D009570:Nitriles D010879:Piperazines D011725:Pyridines D020123:Sirolimus D058570:TOR Serine-Threonine Kinases
CDKN1A CDKN2A aging cancer rapalogs