Inhibition of p21 activates Akt kinase to trigger ROS-induced autophagy and impacts on tumor growth rate.
Mayank MaheshwariNisha YadavMohammad HasanainPraveen PandeyRohit SahaiKuldeep ChoyalAkhilesh SinghMushtaq A NengrooKrishan K SainiDeepak KumarKalyan MitraDipak DattaJayanta SarkarPublished in: Cell death & disease (2022)
Owing to its ability to induce cellular senescence, inhibit PCNA, and arrest cell division cycle by negatively regulating CDKs as well as being a primary target of p53, p21 is traditionally considered a tumor suppressor. Nonetheless, several reports in recent years demonstrated its pro-oncogenic activities such as apoptosis inhibition by cytosolic p21, stimulation of cell motility, and promoting assembly of cyclin D-CDK4/6 complex. These opposing effects of p21 on cell proliferation, supported by the observations of its inconsistent expression in human cancers, led to the emergence of the concept of "antagonistic duality" of p21 in cancer progression. Here we demonstrate that p21 negatively regulates basal autophagy at physiological concentration. Akt activation, upon p21 attenuation, driven ROS accumulation appears to be the major underlying mechanism in p21-mediated modulation of autophagy. We also find p21, as a physiological inhibitor of autophagy, to have oncogenic activity during early events of tumor development while its inhibition favors survival and growth of cancer cells in the established tumor. Our data, thereby, reveal the potential role of autophagy in antagonistic functional duality of p21 in cancer.
Keyphrases
- cell death
- endoplasmic reticulum stress
- signaling pathway
- cell proliferation
- oxidative stress
- cell cycle arrest
- cell cycle
- single cell
- dna damage
- endothelial cells
- papillary thyroid
- poor prognosis
- cell therapy
- pi k akt
- squamous cell
- stem cells
- reactive oxygen species
- transcription factor
- squamous cell carcinoma
- emergency department
- binding protein
- young adults
- gene expression
- staphylococcus aureus
- risk assessment
- adverse drug
- artificial intelligence
- deep learning
- stress induced