Therapy resistance and metastasis, the most fatal steps in cancer, are often triggered by a (partial) activation of the epithelial–mesenchymal transition (EMT) programme. A mesenchymal phenotype predisposes to ferroptosis, a cell death pathway exerted by an iron and oxygen-radical-mediated peroxidation of phospholipids containing polyunsaturated fatty acids. We here show that various forms of EMT activation, including TGFβ stimulation and acquired therapy resistance, increase ferroptosis susceptibility in cancer cells, which depends on the EMT transcription factor Zeb1. We demonstrate that Zeb1 increases the ratio of phospholipids containing pro-ferroptotic polyunsaturated fatty acids over cyto-protective monounsaturated fatty acids by modulating the differential expression of the underlying crucial enzymes stearoyl-Co-A desaturase 1 (SCD), fatty acid synthase (FASN), fatty acid desaturase 2 (FADS2), elongation of very long-chain fatty acid 5 (ELOVL5) and long-chain acyl-CoA synthetase 4 (ACSL4). Pharmacological inhibition of selected lipogenic enzymes (SCD and FADS2) allows the manipulation of ferroptosis sensitivity preferentially in high-Zeb1-expressing cancer cells. Our data are of potential translational relevance and suggest a combination of ferroptosis activators and SCD inhibitors for the treatment of aggressive cancers expressing high Zeb1.
Mutations in LMNA gene are frequently identified in patients suffering from a genetic disorder known as Hutchison–Gilford progeria syndrome (HGPS), providing an ideal model for the understanding of the mechanisms of aging. Lamin A, encoded by LMNA, is an essential component of the subnuclear domain‒nuclear speckles; however, the functional significance in aging is unclear. Here, we show that Lamin A interacts with the m6A methyltransferases, METTL3 and METTL14 in nuclear speckles. Lamin A deficiency compromises the nuclear speckle METTL3/14 reservoir and renders these methylases susceptible to proteasome‐mediated degradation. Moreover, METTL3/14 levels progressively decline in cells undergoing replicative senescence. Overexpression of METTL14 attenuates both replicative senescence and premature senescence. The data reveal an essential role for Lamin A in safeguarding the nuclear speckle reservoir of the m6A methylase METTL14 to antagonize cellular senescence.
N-acetyltransferase 10 catalyzes RNA N4-acetylcytidine (ac4C) modifications and thus regulates RNA stability and translation efficiency. However, the deacetylase for ac4C is unknown. SIRT7 was initially identified as an NAD+-dependent protein deacetylase and plays essential roles in genome stability, circadian rhythms, metabolism, and aging. In this study, we identified SIRT7 as a deacetylase of the ac4C of ribosomal (r)RNA for the first time and found it to be NAD+-independent. Our data highlight the important role of SIRT7 in rRNA ac4C modification and suggest an additional epitranscriptional regulation of aging.
Defective nuclear lamina protein lamin A is associated with premature aging. Casein kinase 2 (CK2) binds the nuclear lamina, and inhibiting CK2 activity induces cellular senescence in cancer cells. Thus, it is feasible that lamin A and CK2 may cooperate in the aging process. Nuclear CK2 localization relies on lamin A and the lamin A carboxyl terminus physically interacts with the CK2α catalytic core and inhibits its kinase activity. Loss of lamin A in Lmna-knockout mouse embryonic fibroblasts (MEFs) confers increased CK2 activity. Conversely, prelamin A that accumulates in Zmpste24-deficent MEFs exhibits a high CK2α binding affinity and concomitantly reduces CK2 kinase activity. Permidine treatment activates CK2 by releasing the interaction between lamin A and CK2, promoting DNA damage repair and ameliorating progeroid features. These data reveal a previously unidentified function for nuclear lamin A and highlight an essential role for CK2 in regulating senescence and aging.
Biological aging is characterized by irreversible cell cycle blockade, a decreased capacity for tissue regeneration, and an increased risk of age-related diseases and mortality. A variety of genetic and epigenetic factors regulate aging, including the abnormal expression of aging-related genes, increased DNA methylation levels, altered histone modifications, and unbalanced protein translation homeostasis. The epitranscriptome is also closely associated with aging. Aging is regulated by both genetic and epigenetic factors, with significant variability, heterogeneity, and plasticity. Understanding the complex genetic and epigenetic mechanisms of aging will aid the identification of aging-related markers, which may in turn aid the development of effective interventions against this process. This review summarizes the latest research in the field of aging from a genetic and epigenetic perspective. We analyze the relationships between aging-related genes, examine the possibility of reversing the aging process by altering epigenetic age.
Cutaneous wound healing, an integral part for protection of skin barrier, is a complex biological process and intimately associated with keratinocyte migration. However, mechanisms regulating keratinocyte migration in the process of cutaneous wound repair remain largely unknown. Here, we found that N-acetyltransferase 10 (NAT10) is essential for cutaneous wound repair in an in vivo skin wound healing model—a significant delay of wound repair in Nat10 haploinsufficient mice and a remarkable inhibition of keratinocyte migration by NAT10 knockdown in an in vitro keratinocyte migration model. We further demonstrate that loss of NAT10 expression attenuates the wound-induced IL-6/IL-8 expression through inhibiting NF-κB/p65 activity in keratinocytes. By deeply digging, silencing NAT10 compromises the level of nuclear p65 by facilitating its poly-ubiquitination, thus accelerates its degradation in the nucleus. Notably, we detected a strong positive correlation between the expression of NAT10 and relevant NF-kB/p65-IL6 signaling activity in mouse wound skin tissues. Overall, our study reveals an important role of NAT10 on cutaneous wound repair by potentiating NF-κB/p65-IL-6/8-STAT3 signaling. Targeting NAT10 might be a potential strategy for the treatment of skin wound dysfunctions and related diseases.