Hepatocellular carcinoma (HCC) is one of the most fatal cancers worldwide. In this article, we show that expression of abnormal spindle‐like microcephaly‐associated protein (ASPM) is up‐regulated in liver cancer samples, and this up‐regulation is significantly associated with tumor aggressiveness and reduced survival times of patients. Down‐regulation of ASPM expression inhibits the proliferation, invasion, migration and epithelial‐to‐mesenchymal transition of HCC cells in vitro and inhibits tumor formation in nude mice. ASPM interacts with disheveled‐2 (Dvl2) and antagonizes autophagy‐mediated Dvl2 degradation by weakening the functional interaction between Dvl2 and the lipidated form of microtubule‐associated proteins 1A/1B light chain 3A (LC3II), thereby increasing Dvl2 protein abundance and leading to Wnt/β‐catenin signaling activation in HCC cells. Thus, our results define ASPM as a novel oncoprotein in HCC and indicate that disruption of the Wnt–ASPM–Dvl2–β‐catenin signaling axis might have potential clinical value.

Objective: Knowledge of the role of CYP2E1 in hepatocarcinogenesis is largely based on epidemiological and animal studies, with a primary focus on the role of CYP2E1 in metabolic activation of procarcinogens. Few studies have directly assessed the effects of CYP2E1 on HCC malignant phenotypes.Methods: The expression of CYP2E1 in HCC tissues was determined by qRT-PCR, western blotting and immunohistochemistry. Overexpression of CYP2E1 in HCC cell was achieved by lentivirus transfection. The function of CYP2E1 were detected by CCK-8, wound healing, transwell assays, xenograft models and pulmonary metastasis model. TOP/FOPFlash reporter assay, western blotting, functional rescue experiments, Co-immunoprecipitation and reactive oxygen species detection were conducted to reveal the underlying mechanism of the tumor suppressive role of CYP2E1.Results: CYP2E1 expression is down-regulated in HCC tissues, and this downregulation was associated with large tumor diameter, vascular invasion, poor differentiation, and shortened patient survival time. Ectopic expression of CYP2E1 inhibits the proliferation, invasion and migration and epithelial-to-mesenchymal transition of HCC cells in vitro, and inhibits tumor formation and lung metastasis in nude mice. Mechanistic investigations show that CYP2E1 overexpression significantly inhibited Wnt/β-catenin signaling activity and decreased Dvl2 expression in HCC cells. An increase in Dvl2 expression restored the malignant phenotype of HCC cells. Notably, CYP2E1 promoted the ubiquitin-mediated degradation of Dvl2 by strengthening the interaction between Dvl2 and the E3 ubiquitin ligase KLHL12 in CYP2E1-stable HCC cells. CYP2E1-induced ROS accumulation was a critical upstream event in the Wnt/β-Catenin pathway in CYP2E1-overexpressing HCC cells.Conclusions: These results provide novel insight into the role of CYP2E1 in HCC and the tumor suppressor role of CYP2E1 can be attributed to its ability to manipulate Wnt/Dvl2/β-catenin pathway via inducing ROS accumulation, which provides a potential target for the prevention and treatment of HCC.Graphical

Introduction: This study investigates the effects of varying nicotine doses and administration frequencies on mouse body weight, adipose tissues, and liver. Aims and Methods: Male C57BL6/J mice received subcutaneous nicotine doses (0.5, 1, or 2 mg/kg) once daily (qd), twice daily (bid), or four times daily (qid) for 4 weeks. Body weight, inguinal white adipose tissue (iWAT), epididymal white adipose tissue (eWAT), brown adipose tissue (BAT) weight and size, and UCP1 expression were assessed, along with liver fat deposition and morphology. Results: Nicotine administration reduced body weight and decreased the weight and size of iWAT and eWAT compared to controls. The frequency of nicotine administration had a more significant impact on body weight and fat tissues than the dosage itself, with 2 mg/kg bid being optimal for weight reduction. Nicotine increased BAT cell numbers and amplified UCP1 expression in iWAT and BAT. It had minor effects on eWAT UCP1 expression and no substantial impact on liver fat deposition or morphology, except for a reduction in liver weight with doses exceeding 4 mg/kg. Conclusions: Nicotine-induced weight reduction is frequency-dependent, with 2 mg/kg bid being the optimal regimen. The mechanisms may include reductions in iWAT and eWAT weights and cell sizes, induction of browning in iWAT, increased BAT quantity and UCP1 expression, and heightened energy expenditure in iWAT and BAT. Nicotine’s ability to induce eWAT browning is relatively weak, indicating diverse mechanisms of action across different adipose tissue types. These findings provide a foundation for further exploration of nicotine’s multifaceted functions and underlying mechanisms. Implications: This study examines how different nicotine doses and administration frequencies affect mouse body weight and adipose tissues. It finds that administering nicotine bid (twice daily) at 2 mg/kg leads to optimal weight reduction. Nicotine induces browning in white adipose tissue, increases BAT quantity and UCP1 expression, and affects energy expenditure. The findings underscore nicotine’s nuanced effects across different adipose tissue types and lay the groundwork for further exploration of its mechanisms and therapeutic potential in weight management.

Cytochrome P450 1A2 (CYP1A2) is a known tumor suppressor in hepatocellular carcinoma (HCC), but its expression is repressed in HCC and the underlying mechanism is unclear. In this study, we investigated the epigenetic mechanisms of CYP1A2 repression and potential therapeutic implications. In HCC tumor tissues, the methylation rates of CYP1A2 CpG island (CGI) and DNMT3A protein levels were significantly higher, and there was a clear negative correlation between DNMT3A and CYP1A2 protein expression. Knockdown of DNMT3A by siRNA significantly increased CYP1A2 expression in HCC cells. Additionally, treating HCC cells with decitabine (DAC) resulted in a dose-dependent upregulation of CYP1A2 expression by reducing the methylation level of CYP1A2 CGI. Furthermore, we observed a decreased enrichment of H3K27Ac in the promoter region of CYP1A2 in HCC tissues. Treatment with the trichostatin A (TSA) restored CYP1A2 expression in HCC cells by increasing H3K27Ac levels in the CYP1A2 promoter region. Importantly, combination treatment of sorafenib with DAC or TSA resulted in a leftward shift of the dose-response curve, lower IC₅₀ values, and reduced colony numbers in HCC cells. Our findings suggest that hypermethylation of the CGI at the promoter, mediated by the high expression of DNMT3A, and hypoacetylation of H3K27 in the CYP1A2 promoter region, leads to CYP1A2 repression in HCC. Epigenetic drugs DAC and TSA increase HCC cell sensitivity to sorafenib by restoring CYP1A2 expression. Our study provides new insights into the epigenetic regulation of CYP1A2 in HCC and highlights the potential of epigenetic drugs as a therapeutic approach for HCC. Significance Statement This study marks the first exploration of the epigenetic mechanisms underlying CYP1A2 suppression in hepatocellular carcinoma (HCC). Our findings reveal that heightened Dnmt3a expression induces hypermethylation of the CGI at the promoter, coupled with diminished H3K27Ac levels, resulting in the repression of CYP1A2 in HCC. The use of epigenetic drugs such as decitabine (DAC) and trichostatin A (TSA) emerges as a novel therapeutic avenue, demonstrating their potential to restore CYP1A2 expression and enhance sorafenib sensitivity in HCC cells.