PurposeLipid rafts are cholesterol enriched microdomains that colocalize signaling pathways involved in cell proliferation, metastasis, and angiogenesis. We examined the effect of methyl-β-cyclodextrin (MβCD)-mediated cholesterol extraction on the proliferation, adhesion, invasion, and angiogenesis of triple negative breast cancer (TNBC) cells.MethodsWe measured cholesterol and estimated cell toxicity. Detergent resistant membrane (DRM) and non-DRM fractions were separated using the OptiPrep gradient method. Cell cycles stages were analyzed by flow cytometry, apoptosis was assessed using the TdT-mediated dUTP nick end-labeling assay, and metastasis was determined using a Matrigel invasion assay. Neo-vessel pattern and levels of angiogenic modulators were determined using an in vitro angiogenesis assay and an angiogenesis array, respectively.ResultsThe present study found that the cholesterol-depleting agent MβCD, efficiently depleted membrane cholesterol and caused concentration dependent (0.1–0.5 mM) cytotoxicity compared to nystatin and filipin III in TNBC cell lines, MDA-MB 231 and MDA-MB 468. A reduced proportion of caveolin-1 found in DRM fractions indicated a cholesterol extraction-induced disruption of lipid raft integrity. MβCD inhibited 52% of MDA-MB 231 cell adhesion on fibronectin and 56% of MDA-MB 468 cell adhesion on vitronectin, while invasiveness of these cells was decreased by 48% and 52% respectively, following MβCD treatment (48 hours). MβCD also caused cell cycle arrest at the G2M phase and apoptosis in MDA-MB 231 cells (25% and 58% cells, respectively) and in MDA-MB 468 cells (30% and 38% cells, respectively). We found that MβCD treated cells caused a 52% and 58% depletion of neovessel formation in both MDA-MB 231 and MDA-MB 468 cell lines, respectively. This study also demonstrated that MβCD treatment caused a respective 2.6- and 2.5-fold depletion of tyrosine protein kinase receptor (TEK) receptor tyrosine kinase levels in both TNBC cell lines.ConclusionMβCD-induced cholesterol removal enhances alterations in lipid raft integrity, which reduces TNBC cell survival.
Andropause or male menopause is defined as androgen decline and onset of hypogonadism in the aging male. Testosterone deficiency in adult male is associated with diabetes mellitus, coronary artery disease, and heart failure. Type 2 diabetic male patients aged above 30 years showed low testosterone levels which is common in diabetic men and had symptoms of hypogonadism. Male sexual dysfunction among diabetic patients can include disorders of libido, ejaculatory problems, and erectile dysfunctions are common among people with diabetes, particularly in older men who had diabetes for years. Older diabetics tend to have both impaired insulin release as well as insulin resistance. There is growing evidence indicating the pathophysiological connections among the mechanisms of oxidative damage by disruption of the oxidative balance, increased levels of enzymatic glycation products in testicular region and glucose transporters, obesity and proinflammatory cytokines in male infertile patients with diabetes. Epidemiological studies suggest that many clinical findings in diabetics are linked to low testosterone levels. This article reviews pathophysiological mechanisms, observational studies, and clinical implications of testosterone therapy in type 2 diabetes mellitus.
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