PTOV1: a novel testosterone-induced atherogenic gene in human aorta

Testosterone therapy and cardiovascular diseases

Since it was first synthesised in 1935, testosterone (T) has been viewed as the mythical Fountain of Youth, promising rejuvenation, restoring sexual appetites, growing stronger muscles, and quicker thinking. T is endowed with direct effects on myocardial and vascular structure and function, as well as on risk factors for cardiovascular (CV) disease. Indeed, low serum T levels are a risk factor for diabetes, metabolic syndrome, inflammation, and dyslipidaemia. Moreover, many studies have shown that T deficiency per se is an independent risk factor of CV and all-cause mortality. On this background and due to direct-to-patient marketing by drug companies, we have witnessed to the widespread use of T replacement therapy (TT) without clear indications particularly in late-life onset hypogonadism. The current review will dwell upon current evidence and controversies surrounding the role of T in the pathophysiology of CV diseases, the link between circulating T levels and CV risk, and the use of replacing T as a possible adjuvant treatment in specific CV disorders. Specifically, recent findings suggest that heart failure and type 2 diabetes mellitus represent two potential targets of T therapy once that a state of hypogonadism is diagnosed. However, only if ongoing studies solve the CV safety issue the T orchid may eventually 'bloom'.

Late-onset hypogonadism: Reductio ad absurdum of the cardiovascular risk-benefit of testosterone replacement therapy

BACKGROUND

Low testosterone (T) level is considered a marker of poor cardiovascular health. Ten years ago, the Testosterone in Older Men with Mobility Limitations (TOM) trial was discontinued due to a higher number of adverse events in men receiving T compared with placebo. Since then, several studies have investigated the risks of T replacement therapy (TRT) in late-onset hypogonadism (LOH).

OBJECTIVE

To review the mechanism by which TRT could damage the cardiovascular system.

MATERIALS AND METHODS

Comprehensive literature search of recent clinical and experimental studies.

RESULTS

The mechanisms of T-mediated coronary vasodilation were reviewed with emphasis on calcium-activated and ATP-sensitive potassium ion channels. We showed how T regulates endothelial nitric oxide synthase (eNOS) and phosphoinositide 3-kinase/protein kinase B/eNOS signaling pathways in vessel walls and its direct effects on cardiomyocytes via β1-adrenergic and ryanodine receptors and provided data on myocardial infarction and heart failure. Vascular smooth muscle senescence could be explained by the modulation of growth factors, matrix metalloproteinase-2, and angiotensin II by T. Furthermore, leukocyte trafficking, facilitated by changes in TNF-α, could explain some of the effects of T on atheromatous plaques. Conflicting data on prothrombotic risk linked to platelet aggregation inhibition via NO-triggered arachidonate synthesis or increased aggregability due to enhanced thromboxane A in human platelets provide evidence regarding the hypotheses on plaque maturation and rupture risk. The effects of T on cardiac electrophysiology and oxygen delivery were also reviewed.

DISCUSSION

The effects of TRT on the cardiovascular system are complex. Although molecular studies suggest a potential benefit, several clinical observations reveal neutral or occasionally detrimental effects, mostly due to confounding factors.

CONCLUSIONS

Attempts to demonstrate that TRT damages the cardiovascular system via systematic analysis of the putative mechanisms led to the contradiction of the initial hypothesis. Current evidence indicates that TRT is safe once other comorbidities are addressed.

Prostate tumor overexpressed-1, in conjunction with human papillomavirus status, predicts outcome in early-stage human laryngeal squamous cell carcinoma

In human cancer, molecular markers combined with clinical characteristics are used increasingly to predict prognosis. Prostate tumor overexpressed-1 (PTOV1), first identified in prostate cancer, is a key factor in tumor progression and correlates with unfavorable clinical outcomes. HPV infection status was tested by HPV E6-targeted multiplex real-time PCR and p16 immunohistochemistry (IHC). Real-time PCR and western blotting analyses were used to examine the mRNA and protein expression levels of PTOV1 in eight paired LSCC samples. IHC was performed to assess PTOV1 protein expression in 196 paraffin-embedded, archived LSCC samples. PTOV1 protein and mRNA expression was increased in LSCC tissues compared with adjacent noncancerous tissue samples. High expression of PTOV1was significantly associated with advanced TNM stage by the X² test. Multivariate analysis revealed that PTOV1 and HPV status were independent prognostic indicators of overall survival (OS) and progression-free survival (PFS) (P = 0.001, P = 0.009 for OS, P = 0.005, P = 0.012 for PFS, respectively). Our study provides the first evidence that the combination of PTOV1 expression level and HPV status provides more prognostic information compared with HPV status alone with the significance still exists in the HPV negative subgroup.

Overexpressed PTOV1 associates with tumorigenesis and progression of esophageal squamous cell carcinoma

PTOV1 has been demonstrated to play an extensive role in many types of cancers. This study takes the first step to clarify the potential relationship between esophageal squamous cell carcinoma and PTOV1 expression and highlight the link between PTOV1 and the tumorigenesis, progression, and prognosis of esophageal squamous cell carcinoma. PTOV1 expression was detected by quantitative reverse transcription polymerase chain reaction and western blotting or immunohistochemical staining in esophageal squamous cell carcinoma cell lines, esophageal squamous cell carcinoma tissues, and its paired adjacent non-cancerous tissues. Moreover, we have analyzed the relationship between PTOV1 expression and clinicopathological features of esophageal squamous cell carcinoma. Survival analysis and Cox regression analysis were used to assess its prognostic significance. We found that PTOV1 expression was significantly higher in the esophageal squamous cell carcinoma cell lines and tissues at messenger RNA level (p < 0.001) and protein level (p < 0.001). Gender, tumor size, or differentiation was tightly associated with the PTOV1 expression. Lymph node involvement (p < 0.001) and TNM stage (p < 0.001) promoted a high PTOV1 expression. A prognostic significance of PTOV1 was also found by Log-rank method, and the overexpression of PTOV1 was related to a shorter OS and DFS. Multiple Cox regression analysis indicated overexpressed PTOV1 as an independent indicator for adverse prognosis. In conclusion, this study takes the lead to demonstrate that the overexpressed PTOV1 plays a vital role in the tumorigenesis and progression of esophageal squamous cell carcinoma, and it is potentially a valuable prognostic predicator and new chemotherapeutic target for esophageal squamous cell carcinoma.

Prostate Tumor Overexpressed 1 (PTOV1) Is a Novel Prognostic Marker for Nasopharyngeal Carcinoma Progression and Poor Survival Outcomes

BACKGROUND

Prostate tumor overexpressed 1 (PTOV1) has been reported to contribute to increased cancer proliferation. However, the clinical significance of PTOV1 in the development and progression of nasopharyngeal carcinoma (NPC) is unclear. Our study aimed to investigate the expression pattern of PTOV1 in NPC and its correlation with clinicopathological features of patients.

METHODS

Western blotting and real-time PCR were conducted to examine PTOV1 expression levels in NPC cell lines and biopsy tissues compared with normal controls. Immunohistochemistry (IHC) was performed to analyze PTOV1 protein expression in paraffin-embedded tissues from 123 patients. Statistical analyses were applied to evaluate the clinical significance of PTOV1 expression.

RESULTS

PTOV1 mRNA and protein levels were upregulated in NPC cell lines and clinical samples. IHC analyses showed that PTOV1 was highly expressed in 68 (55.3%) of 123 NPC specimens. Statistical analysis revealed that PTOV1 expression was significantly correlated with clinical stage (P < 0.001), T classification (P = 0.042) and N classification (P = 0.001). Patients with a higher PTOV1 expression had shorter overall survival compared with those with a lower PTOV1 expression level, especially in lower N stage patients. Multivariate analyses suggested that PTOV1 expression was an independent prognostic marker for survival in NPC patients.

CONCLUSIONS

Our data demonstrated that PTOV1 overexpression is associated with poor survival outcomes of NPC patients, especially in N0-1 patients. Hence, PTOV1 may help to detect early lymph node metastasis of NPC patients and serve as an independent prognostic biomarker for human NPC.

Retinoic acid receptors: from molecular mechanisms to cancer therapy

Retinoic acid (RA), the major bioactive metabolite of retinol or vitamin A, induces a spectrum of pleiotropic effects in cell growth and differentiation that are relevant for embryonic development and adult physiology. The RA activity is mediated primarily by members of the retinoic acid receptor (RAR) subfamily, namely RARα, RARβ and RARγ, which belong to the nuclear receptor (NR) superfamily of transcription factors. RARs form heterodimers with members of the retinoid X receptor (RXR) subfamily and act as ligand-regulated transcription factors through binding specific RA response elements (RAREs) located in target genes promoters. RARs also have non-genomic effects and activate kinase signaling pathways, which fine-tune the transcription of the RA target genes. The disruption of RA signaling pathways is thought to underlie the etiology of a number of hematological and non-hematological malignancies, including leukemias, skin cancer, head/neck cancer, lung cancer, breast cancer, ovarian cancer, prostate cancer, renal cell carcinoma, pancreatic cancer, liver cancer, glioblastoma and neuroblastoma. Of note, RA and its derivatives (retinoids) are employed as potential chemotherapeutic or chemopreventive agents because of their differentiation, anti-proliferative, pro-apoptotic, and anti-oxidant effects. In humans, retinoids reverse premalignant epithelial lesions, induce the differentiation of myeloid normal and leukemic cells, and prevent lung, liver, and breast cancer. Here, we provide an overview of the biochemical and molecular mechanisms that regulate the RA and retinoid signaling pathways. Moreover, mechanisms through which deregulation of RA signaling pathways ultimately impact on cancer are examined. Finally, the therapeutic effects of retinoids are reported.

Testosterone: a vascular hormone in health and disease

Coronary heart disease is a leading cause of premature death in men. Epidemiological studies have shown a high prevalence of low serum testosterone levels in men with cardiovascular disease (CVD). Furthermore, a low testosterone level is associated in some but not in all observational studies with an increase in cardiovascular events and mortality. Testosterone has beneficial effects on several cardiovascular risk factors, which include cholesterol, endothelial dysfunction and inflammation: key mediators of atherosclerosis. A bidirectional relationship between low endogenous testosterone levels and concurrent illness complicates attempts to validate causality in this association and potential mechanistic actions are complex. Testosterone is a vasoactive hormone that predominantly has vasodilatory actions on several vascular beds, although some studies have reported conflicting effects. In clinical studies, acute and chronic testosterone administration increases coronary artery diameter and flow, improves cardiac ischaemia and symptoms in men with chronic stable angina and reduces peripheral vascular resistance in chronic heart failure. Although the mechanism of the action of testosterone on vascular tone in vivo is not understood, laboratory research has found that testosterone is an L-calcium channel blocker and induces potassium channel activation in vascular smooth muscle cells. Animal studies have consistently demonstrated that testosterone is atheroprotective, whereas testosterone deficiency promotes the early stages of atherogenesis. The translational effects of testosterone between in vitro animal and human studies, some of which have conflicting effects, will be discussed in this review. We review the evidence for a role of testosterone in vascular health, its therapeutic potential and safety in hypogonadal men with CVD, and some of the possible underlying mechanisms.

Nuclear Receptors in atherosclerosis: a superfamily with many 'Goodfellas'

Nuclear Receptors form a superfamily of 48 transcription factors that exhibit a plethora of functions in steroid hormone signaling, regulation of metabolism, circadian rhythm and cellular differentiation. In this review, we describe our current knowledge on the role of Nuclear Receptors in atherosclerosis, which is a multifactorial disease of the vessel wall. Various cell types are involved in this chronic inflammatory pathology in which multiple cellular processes and numerous genes are dysregulated. Systemic risk factors for atherosclerosis are among others adverse blood lipid profiles, enhanced circulating cytokine levels, as well as increased blood pressure. Since many Nuclear Receptors modulate lipid profiles or regulate blood pressure they indirectly affect atherosclerosis. In the present review, we focus on the functional involvement of Nuclear Receptors within the atherosclerotic vessel wall, more specifically on their modulation of cellular functions in endothelial cells, smooth muscle cells and macrophages. Collectively, this overview shows that most of the Nuclear Receptors are athero-protective in atherosclerotic lesions.

Zyxin cooperates with PTOV1 to confer retinoic acid resistance by repressing RAR activity

Retinoids including all-trans retinoic acid (RA) have been widely used for cancer therapy. However, the major obstacle for RA therapy is the acquired resistance of which mechanism remained obscure thus far. Here, we first identified Zyxin that cooperates with PTOV1 for the negative regulation of RA signaling. Our studies on the underlying mechanism indicated that Zyxin, translocating to the nucleus in response to RA, mediates RAR repression by forming a ternary complex with PTOV1 and the RAR coactivator CBP, thereby promoting dissociation of CBP from RAR at the RA-responsive promoter. Consistently, RA-induced cancer cell cytotoxicity was significantly impaired by Zyxin or PTOV1. Overall, our findings suggest that Zyxin and PTOV1 should be considered as critical determinants in cancer therapy with retinoids.

PTOV1 is associated with UCH-L1 and in response to estrogen stimuli during the mouse oocyte development

To investigate the biological significance of ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) involvement in oocyte maturation, we screened for proteins that bound to UCH-L1 in mouse ovaries, and we found that the prostate tumor overexpressed-1 (PTOV1) protein was able to bind to UCH-L1. PTOV1 is highly expressed in prostate cancers and considered as a potential marker for carcinogenesis and the progress of prostate cancer. It was reported that PTOV1 plays an important role in cell cycle regulation, but its role in mammalian oocyte development and meiosis is still unclear. In this paper, it was found that the expression levels of PTOV1 in mouse ovaries progressively increased from prepubescence to adulthood. And we found by immunohistochemistry that PTOV1 spreaded in both the cytoplasm and nuclei of oocytes during prepuberty, but in normal adult mouse oocytes, it concentrated not only in nuclei but also on the plasma membrane, though in some oocytes with abnormal shapes, PTOV1 did not display the typical distribution patterns. In granulosa cells, however, it was found to locate in the cytoplasm at all the selected ages. In postnatal mouse ovaries (28 days), estradiol treatment induced the adult-specific distribution pattern of PTOV1 in oocytes. In addition, UCH-L1 was shown to be associated with CDK1, which participated in the regulation of cell cycle and oocyte maturation. Therefore, we propose that the distribution changes of PTOV1 are age-dependent, and significant for mouse oocyte development and maturation. Moreover, the discovery that PTOV1 is associated with UCH-L1 in mouse oocytes supports the explanations for that UCH-L1 is involved in oocyte development and maturation, especially under the regulation of estrogen.

PTOV1 expression predicts prostate cancer in men with isolated high-grade prostatic intraepithelial neoplasia in needle biopsy

PURPOSE

To analyze the expression of PTOV1 in high-grade prostatic intraepithelial neoplasia (HG-PIN) and to explore its usefulness to predict prostate cancer in patients with isolated HG-PIN in needle biopsy (prostate needle biopsy).

EXPERIMENTAL DESIGN

PTOV1 expression in HG-PIN lesions from 140 patients was analyzed by immunohistochemistry in a semiquantitative manner (Histo-score). HG-PIN derived from 79 radical prostatectomies for prostate cancer and from 11 cistoprostatectomies for bladder cancer without prostate cancer were used as positive and negative controls, respectively. Fifty patients with HG-PIN without concomitant cancer at their first prostate needle biopsy were chosen as the study group. Patients were followed by a mean of 2.5 repeated prostate needle biopsies (1-5), during a mean period of 12.4 months (1-39).

RESULTS

PTOV1 expression in HG-PIN from radical prostatectomies showed a significantly higher Histo-score (162.6) compared with specimens from cistoprostatectomies (67.0). In the study group, PTOV1 expression was significantly higher in samples with cancer in the follow-up (11 patients, 22%) compared with samples in which cancer was not detected (151.4 versus 94.6). PTOV1 expression was the only independent predictor of cancer in the multivariate analysis and the area under the curve was 0.803 (95% confidence interval, 0.728-0.878). A threshold of 100 for PTOV1 expression provided 90.9% sensitivity, 51.3% specificity, 34.5% positive predictive value, and 95.2% negative predictive value.

CONCLUSIONS

PTOV1 is overexpressed in HG-PIN associated with cancer and is a potential marker for studying the carcinogenesis and progression of prostate cancer. Prostate needle biopsy with PTOV1 expression in HG-PIN above a threshold of 100 should be repeated immediately for the likely presence of undiagnosed cancer.