Molecular inhibition of RAS signalling to target ageing and age-related health

Uncovering the Molecular Pathways Implicated in the Anti-Cancer Activity of the Imidazoquinoxaline Derivative EAPB02303 Using a Caenorhabditis elegans Model

Imiqualines are analogues of the immunomodulatory drug imiquimod. EAPB02303, the lead of the second-generation imiqualines, is characterized by significant anti-tumor effects with IC50s in the nanomolar range. We used Caenorhabditis elegans transgenic and mutant strains of two key signaling pathways (PI3K-Akt and Ras-MAPK) disrupted in human cancers to investigate the mode of action of EAPB02303. The ability of this imiqualine to inhibit the insulin/IGF1 signaling (IIS) pathway via the PI3K-Akt kinase cascade was explored through assessing the lifespan of wild-type worms. Micromolar doses of EAPB02303 significantly enhanced longevity of N2 strain and led to the nuclear translocation and subsequent activation of transcription factor DAF-16, the only forkhead box transcription factor class O (Fox O) homolog in C. elegans. Moreover, EAPB02303 significantly reduced the multivulva phenotype in let-60/Ras mutant strains MT2124 and MT4698, indicative of its mode of action through the Ras pathway. In summary, we showed that EAPB02303 potently reduced the activity of IIS and Ras-MAPK signaling in C. elegans. Our results revealed the mechanism of action of EAPB02303 against human cancers associated with hyperactivated IIS pathway and oncogenic Ras mutations.

DNA Methylation-derived biological age and long-term mortality risk in subjects with type 2 diabetes

BACKGROUND

Individuals with type 2 diabetes (T2D) face an increased mortality risk, not fully captured by canonical risk factors. Biological age estimation through DNA methylation (DNAm), i.e. the epigenetic clocks, is emerging as a possible tool to improve risk stratification for multiple outcomes. However, whether these tools predict mortality independently of canonical risk factors in subjects with T2D is unknown.

METHODS

Among a cohort of 568 T2D patients followed for 16.8 years, we selected a subgroup of 50 subjects, 27 survived and 23 deceased at present, passing the quality check and balanced for all risk factors after propensity score matching. We analyzed DNAm from peripheral blood leukocytes using the Infinium Human MethylationEPIC BeadChip (Illumina) to evaluate biological aging through previously validated epigenetic clocks and assess the DNAm-estimated levels of selected inflammatory proteins and blood cell counts. We tested the associations of these estimates with mortality using two-stage residual-outcome regression analysis, creating a reference model on data from the group of survived patients.

RESULTS

Deceased subjects had higher median epigenetic age expressed with DNAmPhenoAge algorithm (57.49 [54.72; 60.58] years. vs. 53.40 [49.73; 56.75] years; p = 0.012), and accelerated DunedinPoAm pace of aging (1.05 [1.02; 1.11] vs. 1.02 [0.98; 1.06]; p = 0.012). DNAm PhenoAge (HR 1.16, 95% CI 1.05-1.28; p = 0.004) and DunedinPoAm (HR 3.65, 95% CI 1.43-9.35; p = 0.007) showed an association with mortality independently of canonical risk factors. The epigenetic predictors of 3 chronic inflammation-related proteins, i.e. CXCL10, CXCL11 and enRAGE, C-reactive protein methylation risk score and DNAm-based estimates of exhausted CD8 + T cell counts were higher in deceased subjects when compared to survived.

CONCLUSIONS

These findings suggest that biological aging, as estimated through existing epigenetic tools, is associated with mortality risk in individuals with T2D, independently of common risk factors and that increased DNAm-surrogates of inflammatory protein levels characterize deceased T2D patients. Replication in larger cohorts is needed to assess the potential of this approach to refine mortality risk in T2D.

Trametinib ameliorates aging-associated gut pathology in Drosophila females by reducing Pol III activity in intestinal stem cells

Pharmacological therapies are promising interventions to slow down aging and reduce multimorbidity in the elderly. Studies in animal models are the first step toward translation of candidate molecules into human therapies, as they aim to elucidate the molecular pathways, cellular mechanisms, and tissue pathologies involved in the anti-aging effects. Trametinib, an allosteric inhibitor of MEK within the Ras/MAPK (Ras/Mitogen-Activated Protein Kinase) pathway and currently used as an anti-cancer treatment, emerged as a geroprotector candidate because it extended lifespan in the fruit fly Drosophila melanogaster. Here, we confirm that trametinib consistently and robustly extends female lifespan, and reduces intestinal stem cell (ISC) proliferation, tumor formation, tissue dysplasia, and barrier disruption in guts in aged flies. In contrast, pro-longevity effects of trametinib are weak and inconsistent in males, and it does not influence gut homeostasis. Inhibition of the Ras/MAPK pathway specifically in ISCs is sufficient to partially recapitulate the effects of trametinib. Moreover, in ISCs, trametinib decreases the activity of the RNA polymerase III (Pol III), a conserved enzyme synthesizing transfer RNAs and other short, non-coding RNAs, and whose inhibition also extends lifespan and reduces gut pathology. Finally, we show that the pro-longevity effect of trametinib in ISCs is partially mediated by Maf1, a repressor of Pol III, suggesting a life-limiting Ras/MAPK-Maf1-Pol III axis in these cells. The mechanism of action described in this work paves the way for further studies on the anti-aging effects of trametinib in mammals and shows its potential for clinical application in humans.

Canagliflozin shares common mTOR and MAPK signaling mechanisms with other lifespan extension treatments

Long-lived mouse models and treatments that extend lifespan, such as Rapamycin, acarbose and 17α- -estradiol, lead to reduction in mTORC1 activity, declines in cap-dependent translation and increases in cap-independent translation. In addition, these treatments reduce the MEK-ERK-MNK (ERK1-2) signaling cascade, leading to reduction in eIF4E phosphorylation, which also regulates mRNA translation. Here, we report that Canagliflozin, a drug that extends lifespan only in male mice reduces mTORC1 and ERK1-2 signaling in male mice only. The data suggest reduction in mTORC1 and ERK pathways are common mechanisms shared by both genetic and pharmacological models of slowed aging in mice. Our data also reveal a significant sexual dimorphism in the ERK1-2 signaling pathway which might help to explain why some drugs can extend lifespan in males but have no effects in female mice.

Promoted Skin Wound Healing by Tail-Amputated Eisenia foetida Proteins via the Ras/Raf/MEK/ERK Signaling Pathway

Skin wound healing is an important fundamental problem in biological and medical fields. This study aimed to investigate wound healing promotion of protein extract from tail-amputated Eisenia foetida (E. foetida) and reveal the mechanism correlated with the Ras/Raf/MEK/ERK signaling pathway. Proteins extracted from tail-amputated E. foetida were applied on rats' full-thickness excisional wounds to evaluate their regenerative efficacy. Rat skin tissues around surgical defects were analyzed by immunofluorescence staining and Western blot methods. The Ras/Raf/MEK/ERK signaling pathway was further investigated in vitro using the NIH3T3 cell line. A tail-amputated protein extract (ES2) from E. foetida significantly accelerated rat wound healing ability via higher re-epithelialization and ECM deposition in the tissue section compared to the blank control and un-amputated earthworm extract groups. Furthermore, ES2 treatment dramatically accumulated the expressions of platelet-derived growth factor (PDGF), transforming growth factor-β (TGF-β), and hydroxyproline (HYP) in wound areas on day 7 without their accumulation on day 21 post-wounding, diminishing excessive scar formation. Accelerated wound healing ability with the ES2 was proved to correlate with the up-regulation of the Ras/Raf/MEK/ERK signaling pathway. The mRNA expression of this pathway increased significantly in NIH3T3 cells after being treated with the ES2 at an appropriate concentration. The tail-amputated E. foetida proteins (ES2) can significantly promote skin wound healing better than the un-amputated earthworm tissue extract without excessive scar tissue formation. This effect was related to the up-regulation of the Ras/Raf/MEK/ERK signaling pathway.