Do p53 stress responses impact organismal aging?

The Important Role of Protein Kinases in the p53 Sestrin Signaling Pathway

p53, a crucial tumor suppressor and transcription factor, plays a central role in the maintenance of genomic stability and the orchestration of cellular responses such as apoptosis, cell cycle arrest, and DNA repair in the face of various stresses. Sestrins, a group of evolutionarily conserved proteins, serve as pivotal mediators connecting p53 to kinase-regulated anti-stress responses, with Sestrin 2 being the most extensively studied member of this protein family. These responses involve the downregulation of cell proliferation, adaptation to shifts in nutrient availability, enhancement of antioxidant defenses, promotion of autophagy/mitophagy, and the clearing of misfolded proteins. Inhibition of the mTORC1 complex by Sestrins reduces cellular proliferation, while Sestrin-dependent activation of AMP-activated kinase (AMPK) and mTORC2 supports metabolic adaptation. Furthermore, Sestrin-induced AMPK and Unc-51-like protein kinase 1 (ULK1) activation regulates autophagy/mitophagy, facilitating the removal of damaged organelles. Moreover, AMPK and ULK1 are involved in adaptation to changing metabolic conditions. ULK1 stabilizes nuclear factor erythroid 2-related factor 2 (Nrf2), thereby activating antioxidative defenses. An understanding of the intricate network involving p53, Sestrins, and kinases holds significant potential for targeted therapeutic interventions, particularly in pathologies like cancer, where the regulatory pathways governed by p53 are often disrupted.

Synthesis of sophocarpine triflorohydrazone and its proliferation inhibition and apoptosis induction activity in myeloma cells through Notch3-p53 signaling activation

Multiple myeloma is indicated by the presence of excessive monoclonal plasma cells in bone marrow, which result in the formation of osteolytic lesions. The present study investigated SCA as anti-proliferative agent for myeloma cells and explored the mechanism associated. Effect of SCA on viabilities of KRASA12 and AMO-1 cells was evaluated by MTT assay and apoptotic ratio using flow cytometry. Protein expression was investigated by western blotting and expression of genes related to Notch3-p53 signaling axis using RT-PCR assay. Increase in SCA concentration caused a significant (P < .01) reduction in KRASA12 and AMO-1 cell viability. The KRASA12 and AMO-1 cell viabilities were reduced to 29% and 21%, respectively on treatment with 21 μM doses of SCA. SCA treatment of KRASA12 and AMO-1 cells significantly (P < .05) increased apoptosis compared with untreated cells. The Bcl-2 (26 kDa) protein expression was reduced whereas the Bax (21 kDa) and cleaved caspase-3 levels elevated in SCA treated KRASA12 and AMO-1 cells. Treatment with SCA significantly promoted Hes1, p53 (53 kDa) and Hey1 mRNA expression in KRASA12 and AMO-1 cells. Treatment of KRASA12 and AMO-1 cells with SCA led to a marked reduction in Notch3 protein expression. SCA inhibits KRASA12 and AMO-1 myeloma cell proliferation by promoting pro-apoptotic proteins. Moreover, SCA treatment suppressed Hes1 and Hey1 mRNA expression and targeted Notch3 expression. Therefore, SCA may be studied further for development of treatment for myeloma.

Comparing the Role of the p53 Gene and Telomerase Enzyme in 'Accelerated Aging Due to Cancer': A Literature Review

Aging is defined as progressive physiological alterations in an organism that lead to senescence. In response to stress, when proliferative-competent cells undergo permanent, irreversible growth arrest (like replicative dividing limit, oncogene activation, oxidative stress, or deoxyribonucleic acid (DNA) damage), it is termed as cellular senescence. Biomarkers p53, telomerase, and other inflammatory cytokines have a vital link with senescence, and directed use of these markers might be useful in manipulating cancer and the aging process. We included studies related to topics ' accelerated aging due to cancer', telomerase's relation to Aging and Cancer, p53's relation to Aging and Cancer, Atherosclerosis and Cancer from Search databases like PubMed and Google Scholar. We relied on peer-reviewed articles and included literature from the last 10 years written in the English language. Degenerative diseases in humans are usually linked to atherosclerosis, and atherosclerosis is associated with short leukocyte telomere length. Cancer itself and its treatment are linked with accelerated aging by causing progressive shortening of telomeres during cell replication, resulting in cell death. Gene p53 is known to have a dual effect that works as a tumor suppressor and has pro-aging side effects. In experimental studies, when p53 overcomes multiple regulatory mechanisms controlling its activity, then only the pro-aging side effects of p53 manifested. This might be a potential key for treating cancer without causing the side-effects of aging. In this review, we aim to explain and summarize the interdependent nature of p53, telomeres, and other conventional mechanisms of aging and cancer like inflammation, oxidative stress, uncontrolled proliferation, angiogenesis, micro ribonucleic acids (RNAs), and apoptosis, with a more synergistic approach that can help in developing new therapeutics and play a potential role in shaping modern human lifespan and revolutionize cancer treatment.

Impaired histomorphology might provoke cell cycle regulators alteration in thymus of children with various congenital heart defects

Thymus, as a primary site of appropriate adaptive immunity formation, is an essential organ in face of a self-tolerance as well as a potential menace from impairment of body integrity. Due to vital selection processes during differentiation and maturation of T lymphocytes, control over cell survival and programmed cell death must be orchestrated in detail. Indeed, thymus is highly sensitive to wide spectrum of stressors that initiate acute structural changes. Hypoxia, one of the most common complications in congenital heart defects (CHDs) patients, provokes stress-induced thymus involution. Disrupted embryolonic development of thymus in association with congenital heart defects, may negatively affect physiological immune mechanisms. We propose that detailed analysis of thymic morphology could critically contribute to unveil the pathophysiology of diseases associated with disrupted adaptive immunity in children with heterogeneous congenital heart diseases.

Contrasting Patterns of Rapid Molecular Evolution within the p53 Network across Mammal and Sauropsid Lineages

Cancer is a threat to multicellular organisms, yet the molecular evolution of pathways that prevent the accumulation of genetic damage has been largely unexplored. The p53 network regulates how cells respond to DNA-damaging stressors. We know little about p53 network molecular evolution as a whole. In this study, we performed comparative genetic analyses of the p53 network to quantify the number of genes within the network that are rapidly evolving and constrained, and the association between lifespan and the patterns of evolution. Based on our previous published data set, we used genomes and transcriptomes of 34 sauropsids and 32 mammals to analyze the molecular evolution of 45 genes within the p53 network. We found that genes in the network exhibited evidence of positive selection and divergent molecular evolution in mammals and sauropsids. Specifically, we found more evidence of positive selection in sauropsids than mammals, indicating that sauropsids have different targets of selection. In sauropsids, more genes upstream in the network exhibited positive selection, and this observation is driven by positive selection in squamates, which is consistent with previous work showing rapid divergence and adaptation of metabolic and stress pathways in this group. Finally, we identified a negative correlation between maximum lifespan and the number of genes with evidence of divergent molecular evolution, indicating that species with longer lifespans likely experienced less variation in selection across the network. In summary, our study offers evidence that comparative genomic approaches can provide insights into how molecular networks have evolved across diverse species.

Apoptosis of mouse myeloma cells induced by curcumin via the Notch3-p53 signaling axis

Resistance to apoptosis is a characteristic of cancer. Curcumin has become a potential anticancer drug for its pro-apoptotic effects, but the underlying mechanisms remain unclear. Furthermore, the Notch3-p53 signaling axis serves an important role in cell fate. The present study was designed to investigate the antitumor effect of curcumin by the Notch3-p53 axis in mouse myeloma P3X63Ag8 cells. The effects of curcumin on the viability of P3X63Ag8 cells were evaluated using an MTT assay. Quantitative expression of the Notch3-p53 signaling axis-associated genes was measured by reverse transcription-quantitative polymerase chain reaction, and western blot analysis was used to investigate the expression of proteins. Additionally, flow cytometry was used to measure the ratio of apoptosis. The results demonstrated that curcumin could significantly inhibit cell viability. No significant pro-apoptotic effect was observed when the concentration of curcumin was <30 µM. At 30 µM, curcumin-treated cells exhibited an apoptotic phenomenon, and the ratio of late apoptosis increased with the concentration of curcumin, and reached 28.4 and 51.8% in the medium- and high-dose groups, respectively. Curcumin inhibited the expression of Notch3, while the middle- and high-dose groups promoted p53. The expression of Notch3-responsive genes Hes family BHLH transcription factor 1 and Hes-related family transcription factor with YRPW motif 1 were notably promoted. Curcumin treatment significantly downregulated B-cell lymphoma-2 (Bcl-2) at the mRNA and protein levels, but upregulated Bcl-2-associated X. These data indicated that curcumin exhibited antitumor effects in mouse myeloma cells with induction of apoptosis by affecting the Notch3-p53 signaling axis.