The effects of 1,4-dimethylpyridine in metastatic prostate cancer in mice

1-Methylnicotinamide promotes hepatic steatosis in mice: A potential mechanism in chronic alcohol-induced fatty liver disease

Alcohol abuse and its related diseases are the major risk factors for human health. Alcohol-related liver disease (ALD) is a leading cause of morbidity and mortality worldwide. Although the mechanism of ALD has been widely investigated, liver metabolites associated with long-term alcohol intake-induced hepatic steatosis have not been well explored. In this study, we aimed to investigate the role and mechanisms of 1-methylnicotinamide (1-MNA), a metabolite during nicotinamide adenine dinucleotide (NAD⁺) metabolism, in the pathogenesis of ALD. C57BL/6 wild-type mice were subjected to chronic alcohol feeding with or without 1-MNA (50 mg/kg/day). Our data showed that 1-MNA administration significantly enhanced chronic alcohol consumption-induced hepatic steatosis. Mechanistic studies revealed that alcohol-increased hepatic protein levels of sterol regulatory element-binding transcription factor (SREBP-1c), a key enzyme that regulates lipid lipogenesis, were enhanced in mice administered with 1-MNA, regardless of alcohol feeding. Consistently, alcohol-increased mRNA and protein levels of hepatic diacylglycerol o-acyltransferase 2 (DGAT2) and very low-density lipoprotein receptor (VLDLR) were also exacerbated by 1-MNA administration. Alcohol-induced hepatic endoplasmic reticulum (ER) stress was enhanced by 1-MNA administration, which was evidenced by increased protein levels of binding immunoglobulin protein (BIP), phosphorylated- protein kinase r-like ER kinase (PERK), activating transcription factor 4 (ATF4), and C/EBP-homologous protein (CHOP) in the mouse liver. Overall, this study demonstrated that 1-MNA serves as a pathogenic factor in the development of ALD. Targeting liver 1-MNA levels may serve as a promising therapeutic approach for improving hepatic steatosis in ALD.

Endothelial SIRT1 as a Target for the Prevention of Arterial Aging: Promises and Challenges

ABSTRACT

SIRT1, a member of the sirtuin family of longevity regulators, possesses potent activities preventing vascular aging. The expression and function of SIRT1 in endothelial cells are downregulated with age, in turn causing early vascular aging and predisposing various vascular abnormalities. Overexpression of SIRT1 in the vascular endothelium prevents aging-associated endothelial dysfunction and senescence, thus the development of hypertension and atherosclerosis. Numerous efforts have been directed to increase SIRT1 signaling as a potential strategy for different aging-associated diseases. However, the complex mechanisms underlying the regulation of SIRT1 have posed a significant challenge toward the design of specific and effective therapeutics. This review aimed to provide a summary on the regulation and function of SIRT1 in the vascular endothelium and to discuss the different approaches targeting this molecule for the prevention and treatment of age-related cardiovascular and cerebrovascular diseases.

Dynamic CTC phenotypes in metastatic prostate cancer models visualized using magnetic ranking cytometry

Tumors can shed thousands of cells into the circulation daily. These circulating tumor cells (CTCs) are heterogeneous, and their phenotypes change dynamically. Real-time monitoring of CTC phenotypes is crucial to elucidate the role of CTCs in the metastatic cascade. Here, we monitor phenotypic changes in CTCs in mice xenografted with tumors with varying aggressiveness during cancer progression and a course of chemotherapy to study the metastatic potential of CTCs and changes in the properties of these cells in response to treatment. A new device that enables magnetic ranking cytometry (MagRC) is employed to profile the phenotypic properties of CTCs. Overall, CTCs from metastatic xenografts in mice display dynamic and heterogeneous profiles while non-metastatic models had static profiles. Decreased heterogeneity followed by a reduction in metastasis incidence was observed after a course of chemotherapy administered to highly metastatic xenografts. Phenotypic profiling of CTCs could be employed to monitor disease progression and predict therapeutic responses.