Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. However, there still remains a lack of effective diagnostic and therapeutic targets for this disease. Increasing evidence demonstrates that RNA modifications play an important role in the progression of HCC, but the role of the N7-methylguanosine (m7G) methylation modification in HCC has not been properly evaluated. Thus, the goal of the present study was to investigate the function and mechanism of the m7G methyltransferase WD repeat domain 4 (WDR4) in HCC as well as its clinical relevance and potential value. We first verified the high expression of WDR4 in HCC and observed that upregulated WDR4 expression increased the m7G methylation level in HCC. WDR4 promoted HCC cell proliferation by inducing the G2/M cell cycle transition and inhibiting apoptosis in addition to enhancing metastasis and sorafenib resistance through epithelial-mesenchymal transition (EMT). Furthermore, we observed that c-MYC (MYC) can activate WDR4 transcription and that WDR4 promotes CCNB1 mRNA stability and translation to enhance HCC progression. Mechanistically, we determined that WDR4 enhances CCNB1 translation by promoting the binding of EIF2A to CCNB1 mRNA. Furthermore, CCNB1 was observed to promote PI3K and AKT phosphorylation in HCC and reduce P53 protein expression by promoting P53 ubiquitination. In summary, we elucidated the MYC/WDR4/CCNB1 signalling pathway and its impact on PI3K/AKT and P53. Furthermore, the result showed that the m7G methyltransferase WDR4 is a tumour promoter in the development and progression of HCC and may act as a candidate therapeutic target in HCC treatment.
Background Metabolically healthy obesity (MHO) and its transition to unhealthy metabolic status have been associated with risk of cardiovascular disease (CVD) in Western populations. However, it is unclear to what extent metabolic health changes over time and whether such transition affects risks of subtypes of CVD in Chinese adults. We aimed to examine the association of metabolic health status and its transition with risks of subtypes of vascular disease across body mass index (BMI) categories. Methods and findings The China Kadoorie Biobank was conducted during 25 June 2004 to 15 July 2008 in 5 urban (Harbin, Qingdao, Suzhou, Liuzhou, and Haikou) and 5 rural (Henan, Gansu, Sichuan, Zhejiang, and Hunan) regions across China. BMI and metabolic health information were collected. We classified participants into BMI categories: normal weight (BMI 18.5–23.9 kg/m²), overweight (BMI 24.0–27.9 kg/m²), and obese (BMI ≥ 28 kg/m²). Metabolic health was defined as meeting less than 2 of the following 4 criteria (elevated waist circumference, hypertension, elevated plasma glucose level, and dyslipidemia). The changes in obesity and metabolic health status were defined from baseline to the second resurvey with combination of overweight and obesity. Among the 458,246 participants with complete information and no history of CVD and cancer, the mean age at baseline was 50.9 (SD 10.4) years, and 40.8% were men, and 29.0% were current smokers. During a median 10.0 years of follow-up, 52,251 major vascular events (MVEs), including 7,326 major coronary events (MCEs), 37,992 ischemic heart disease (IHD), and 42,951 strokes were recorded. Compared with metabolically healthy normal weight (MHN), baseline MHO was associated with higher hazard ratios (HRs) for all types of CVD; however, almost 40% of those participants transitioned to metabolically unhealthy status. Stable metabolically unhealthy overweight or obesity (MUOO) (HR 2.22, 95% confidence interval [CI] 2.00–2.47, p < 0.001) and transition from metabolically healthy to unhealthy status (HR 1.53, 1.34–1.75, p < 0.001) were associated with higher risk for MVE, compared with stable healthy normal weight. Similar patterns were observed for MCE, IHD, and stroke. Limitations of the analysis included lack of measurement of lipid components, fasting plasma glucose, and visceral fat, and there might be possible misclassification. Conclusions Among Chinese adults, MHO individuals have increased risks of MVE. Obesity remains a risk factor for CVD independent of major metabolic factors. Our data further suggest that metabolic health is a transient state for a large proportion of Chinese adults, with the highest vascular risk among those remained MUOO.
We examined the causal direction between gut microbiota–dependent metabolite trimethylamine N-oxide (TMAO) or its predecessors and cardiometabolic diseases, such as risk of type 2 diabetes mellitus (T2DM), coronary artery disease (CAD), myocardial infarction (MI), stroke, atrial fibrillation (AF), and chronic kidney disease (CKD). We used genetic variants as instruments to test the causal associations. Genetically predicted higher TMAO and carnitine were not associated with higher odds of T2DM, AF, CAD, MI, stroke, and CKD after Bonferroni correction (P ≤ 0.0005). However, we observed that genetically increased choline showed a suggestive association with higher risk of T2DM (odds ratio 1.84 [95% CI 1.00–3.42] per 10 units, P = 0.05). In contrast, genetically predicted higher betaine (0.68 [0.48–0.95] per 10 units, P = 0.023) was suggestively associated with a lower risk of T2DM. We observed a suggestive association of genetically increased choline with a lower level of body fat percentage (β ± SE −0.28 ± 0.11, P = 0.013) but a higher estimated glomerular filtration rate (0.10 ± 0.05, P = 0.034). We further found that T2DM (0.130 ± 0.036, P < 0.0001) and CKD (0.483 ± 0.168, P = 0.004) were causally associated with higher TMAO levels. Our Mendelian randomization findings support that T2DM and kidney disease increase TMAO levels and that observational evidence for cardiovascular diseases may be due to confounding or reverse causality.
Purpose: TP53 mutations are highly prevalent in head and neck squamous cell carcinoma (HNSCC) and associated with increased resistance to conventional treatment primarily consisting of chemotherapy and radiation. Restoration of wildtype p53 function in TP53-mutant cancer cells represents an attractive therapeutic approach and has been explored in recent years. In this study, the efficacy of a putative p53 reactivator called COTI-2 was evaluated in HNSCC cell lines with different TP53 status. Experimental Design: Clonogenic survival assays and an orthotopic mouse model of oral cancer were used to examine in vitro and in vivo sensitivity of HNSCC cell lines with either wild-type, null, or mutant TP53 to COTI-2 alone, and in combination with cisplatin and/or radiation. Western blotting, cell cycle, live-cell imaging, RNA sequencing, reversephase protein array, chromatin immunoprecipitation, and apoptosis analyses were performed to dissect molecular mechanisms. Results: COTI-2 decreased clonogenic survival of HNSCC cells and potentiated response to cisplatin and/or radiation in vitro and in vivo irrespective of TP53 status. Mechanistically, COTI-2 normalized wild-type p53 target gene expression and restored DNA-binding properties to the p53-mutant protein in HNSCC. In addition, COTI-2 induced DNA damage and replication stress responses leading to apoptosis and/or senescence. Furthermore, COTI-2 lead to activation of AMPK and inhibition of the mTOR pathways in vitro in HNSCC cells. Conclusions: COTI-2 inhibits tumor growth in vitro and in vivo in HNSCC likely through p53-dependent and p53independent mechanisms. Combination of COTI-2 with cisplatin or radiation may be highly relevant in treating patients with HNSCC harboring TP53 mutations.
Hepatocellular carcinoma (HCC) is one of the most common malignant tumors and a leading cause of cancer-related deaths worldwide. Emerging studies have shown that circular RNAs (circRNAs) are differentially expressed in HCC and play an important role in HCC pathogenesis and metastasis. However, the mechanism of circRNA in the chemoresistance of HCC remains unclear. In this study, we aimed to investigate the role of circRNA in cisplatin resistance of HCC. We identified a novel circRNA circRNA_101505 that was decreased in cisplatin-resistant HCC tissues and cell lines, and associated with a poor survival outcome. Gain-of-function investigations showed that overexpression of circRNA_101505 suppressed cancer cell growth in vivo and in vitro, and enhanced cisplatin toxicity in HCC cells. Mechanistic studies found that circRNA_101505 could sensitize HCC cells to cisplatin by sponging miR-103, and thereby promoting oxidored-nitro domain-containing protein 1 (NOR1) expression. In conclusion, the significant inhibitory effects indicate circRNA_101505 to be a potential therapeutic target for HCC treatment. Our findings provide significant evidence to further elucidate the therapeutic use of circRNA in HCC.
The serine/threonine kinase AKT is a key mediator of cancer cell survival. We demonstrate that transient glucose deprivation modestly induces AKT phosphorylation at both Thr308 and Ser473. In contrast, prolonged glucose deprivation induces selective AKTThr308 phosphorylation and phosphorylation of a distinct subset of AKT downstream targets leading to cell survival under metabolic stress. Glucose deprivation-induced AKTThr308 phosphorylation is dependent on PDK1 and PI3K but not EGFR or IGF1R. Prolonged glucose deprivation induces the formation of a complex of AKT, PDK1, and the GRP78 chaperone protein, directing phosphorylation of AKTThr308 but AKTSer473. Our results reveal a novel mechanism of AKT activation under prolonged glucose deprivation that protects cells from metabolic stress. The selective activation of AKTThr308 phosphorylation that occurs during prolonged nutrient deprivation may provide an unexpected opportunity for the development and implementation of drugs targeting cell metabolism and aberrant AKT signaling.
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