The Kindlin2-p53-SerpinB2 signaling axis is required for cellular senescence in breast cancer

Abstract

In cancer, cellular senescence is a complex process that leads to inhibition of proliferation of cells that may develop a neoplastic phenotype. A plethora of signaling pathways, when dysregulated, have been shown to elicit a senescence response. Two well-known tumor suppressor pathways, controlled by the p53 and retinoblastoma proteins, have been implicated in maintaining the cellular senescence phenotype. Kindlin-2, a member of an actin cytoskeleton organizing and integrin activator proteins, has been shown to play a key role in the regulation of several hallmarks of several cancers, including breast cancer (BC). The molecular mechanisms whereby Kindlin-2 regulates cellular senescence in BC tumors remains largely unknown. Here we show that Kindlin-2 regulates cellular senescence in part through its interaction with p53, whereby it regulates the expression of the p53-responsive genes; i.e., SerpinB2 and p21, during the induction of senescence. Our data show that knockout of Kindlin-2 via CRISPR/Cas9 in several BC cell lines significantly increases expression levels of both SerpinB2 and p21 resulting in the activation of hallmarks of cellular senescence. Mechanistically, interaction between Kindlin-2 and p53 at the promotor level is critical for the regulated expression of SerpinB2 and p21. These findings identify a previously unknown Kindlin-2/p53/SerpinB2 signaling axis that regulates cellular senescence and intervention in this axis may serve as a new therapeutic window for BCs treatment.

WAVE3 phosphorylation regulates the interplay between PI3K, TGF-β, and EGF signaling pathways in breast cancer

“…We applied a combination of genetic and pharmacologic manipulations, as well as different biochemical and cell imaging analyses in vitro and in mouse models, to investigate the role of WAVE3 phosphorylation in the regulation of the growth and progression of BC tumors. Our investigations used CRISPR/Cas9 gene editing to delete WAVE3 in human and murine BC cell lines 22 , 34 , 39 , 43 . We also used lentivirus-mediated infections 34 , 39 to induce expression of either wild-type or phospho-mutant form of WAVE3 in the WAVE3-deficient BC cells.…”

“…Protein cell lysate, co-immunoprecipitation, and western blot analyses were performed according to standards protocols as previously described 34 , 39 .…”

“…BC tumor tissues were collected at the indicated times, snap-frozen in optimal cutting temperature medium (Sakura Finetek), and 8-μm sections were prepared and stained with the following antibodies: rabbit anti pAKT-S473 (1:400), pSMAD3(1:200), pERK1/2 (1:200), AKT (1:400), SMAD3 (1:500), and ERK1/2 (1:400), as described previously 22 , 39 , 42 , 43 . Stained sections were analyzed using fluorescence imaging microscopy (Leica) and ImagePro Plus Capture and Analysis software (Media Cybernetics).…”

“…Stained sections were analyzed using fluorescence imaging microscopy (Leica) and ImagePro Plus Capture and Analysis software (Media Cybernetics). Positive areas were quantified in 15 independent fields/section using the Image Pro-Plus software 22 , 39 , 42 , 43 .…”

Alzheimer’s genetic risk factorFERMT2(Kindlin-2) controls axonal growth and synaptic plasticity in an APP-dependent manner

“…FERMT2 has been reported as a key protein involved in cardiac and skeletal muscle development 4 (Dowling et al 2008), and has been involved in cancer progression (Shen et al 2012;Zhan et al 2012;Sossey-Alaoui et al 2019). However, despite of the fact that FERMT2 is a major genetic risk factor of AD, the physiological and/or pathophysiological roles of FERMT2 in the brain have not been identified.…”