Association of caveolin-1 and -2 genetic variants and post-treatment serum caveolin-1 with prostate cancer risk and outcomes

Molecular pathogenesis, mechanism and therapy of Cav1 in prostate cancer

Prostate cancer is the second incidence of malignant tumors in men worldwide. Its incidence and mortality are increasing year by year. Enhanced expression of Cav1 in prostate cancer has been linked to both proliferation and metastasis of cancer cells, influencing disease progression. Dysregulation of the Cav1 gene shows a notable association with prostate cancer. Nevertheless, there is no systematic review to report about molecular signal mechanism of Cav1 and drug treatment in prostate cancer. This article reviews the structure, physiological and pathological functions of Cav1, the pathogenic signaling pathways involved in prostate cancer, and the current drug treatment of prostate cancer. Cav1 mainly affects the occurrence of prostate cancer through AKT/mTOR, H-RAS/PLCε, CD147/MMPs and other pathways, as well as substance metabolism including lipid metabolism and aerobic glycolysis. Baicalein, simvastatin, triptolide and other drugs can effectively inhibit the growth of prostate cancer. As a biomarker of prostate cancer, Cav1 may provide a potential therapeutic target for the treatment of prostate cancer.

Racial Differences in Germline Genetic Testing for Prostate Cancer: A Systematic Review

PURPOSE

Testing for pathogenic variants can aid in oncologic risk stratification and identification of targeted therapies. Despite known disparities in access to prostate cancer (PCa) care, little has been written about access to germline genetic testing (GGT) for Black men and other historically marginalized populations. This systematic review sought to delineate racial/ethnic disparities in GGT for PCa.

METHODS

This systematic review identified articles published from January 1996 through May 2021 in PubMed, Web of Science, and Embase. We included studies that reported rates of GGT in men with PCa in the United States by race/ethnicity as reflective of routine clinical care or research. A narrative synthesis was performed.

RESULTS

Of 4,309 unique records, 91 studies examining 50 unique study populations met inclusion criteria. Of these, four populations included men who received GGT through routine clinical care, accounting for 4,415 men (72.6% White and 7.2% Black). The other 46 populations included men who received GGT as part of a research study, accounting for 30,824 men (64.3% White and 21.6% Black). Of these 46 research populations, 19 used targeted methods to increase recruitment from a specific demographic.

CONCLUSION

Most studies that report GGT rates by race/ethnicity are in research settings. Many of these studies used targeted recruitment methods and subsequently have a greater proportion of Black men than clinical and US population-based studies. Other historically marginalized populations are not well represented. There remains a knowledge gap regarding the extent of racial disparities in the use of GGT, particularly in the clinical setting.

Caveolae as Potential Hijackable Gates in Cell Communication

Caveolae are membrane microdomains described in many cell types involved in endocytocis, transcytosis, cell signaling, mechanotransduction, and aging. They are found at the interface with the extracellular environment and are structured by caveolin and cavin proteins. Caveolae and caveolins mediate transduction of chemical messages via signaling pathways, as well as non-chemical messages, such as stretching or shear stress. Various pathogens or signals can hijack these gates, leading to infectious, oncogenic and even caveolin-related diseases named caveolinopathies. By contrast, preclinical and clinical research have fallen behind in their attempts to hijack caveolae and caveolins for therapeutic purposes. Caveolae involvement in human disease is not yet fully explored or understood and, of all their scaffold proteins, only caveolin-1 is being considered in clinical trials as a possible biomarker of disease. This review briefly summarizes current knowledge about caveolae cell signaling and raises the hypothesis whether these microdomains could serve as hijackable “gatekeepers” or “gateways” in cell communication. Furthermore, because cell signaling is one of the most dynamic domains in translating data from basic to clinical research, we pay special attention to translation of caveolae, caveolin, and cavin research into clinical practice.

A modern era of personalized medicine in the diagnosis, prognosis, and treatment of prostate cancer

The present era is witnessing rapid advancements in the field of medical informatics and modern healthcare management. The role of translational bioinformatics (TBI), an infant discipline in the field of medical informatics, is pivotal in this revolution. The development of high-throughput technologies [e.g., microarrays, next-generation sequencing (NGS)] has propelled TBI to the next stage in this modern era of medical informatics. In this review, we assess the promising translational outcomes of microarray- and NGS-based discovery of genes, proteins, micro RNAs, and other active biological compounds aiding in the diagnosis, prognosis, and therapy of prostate cancer (PCa) to improve treatment strategies at the localized and/or metastatic stages in patients. Several promising candidate biomarkers in circulating blood (miR-25-3p and miR-18b-5p), urine (miR-95, miR-21, miR-19a, and miR-19b), and prostatic secretions (miR-203) have been identified. AURKA and MYCN, novel candidate biomarkers, were found to be specifically expressed in neuroendocrine PCa. The use of BTNL2 gene mutations and inflammasomes as biomarkers in immune function-mediated, inherited PCa has also been elucidated based on NGS data. Although TBI discoveries can benefit clinical performance metrics, the translational potential and the in vivo performance of TBI outcomes need to be verified. In conclusion, TBI aids in the effective clinical management of PCa; furthermore, the fate of personalized/precision medicine mostly relies on the enhanced diagnostic, prognostic, and therapeutic potential of TBI.

Prognostic value of caveolin-1 in genitourinary cancer: a meta-analysis

We aimed to obtain the most comprehensive picture to date of the prognostic value of caveolin-1 (Cav-1) in genitourinary carcinoma by meta-analyzing all eligible studies in PubMed and EMBASE. Data on patient clinical characteristics, cancer-specific survival (CSS) and recurrence-free survival (RFS) were extracted. The meta-analysis included 6 articles on prostate cancer, 5 on renal cancer, 1 on bladder cancer and 1 on transition cell carcinoma of the upper urinary tract. Two studies examining the association of ELISA-measured Cav-1 levels in serum with RFS in 621 patients with prostate cancer gave a combined hazard ratio (HR) of 1.25 (95% CI 0.36 to 4.36). The other 4 studies on prostate cancer examined the association of immunohistochemically determined Cav-1 levels in cancerous tissue with RFS and gave a combined HR of 1.83 (95% CI 1.36 to 2.47). Three studies on renal cancer examining the association of Cav-1 levels with CSS gave a multivariate HR of 1.98 (95% CI 1.35 to 2.90). The single studies on bladder carcinoma and upper urinary tract carcinoma gave, respectively, a multivariate HR of 2.28 (95% CI 1.09 to 4.74) for the relationship of Cav-1 levels to DFS, and a multivariate HR of 5.08 (95% CI 1.799 to 14.342) for the relationship of Cav-1 levels to CSS. This meta-analysis of available evidence suggests that elevated Cav-1 levels in serum can predict poor survival in patients with genitourinary cancer, which may help identify high-risk patients earlier and guide clinical decision-making.

Value of caveolin-1 in cancer progression and prognosis: Emphasis on cancer-associated fibroblasts, human cancer cells and mechanism of caveolin-1 expression (Review)

Caveolin-1 (Cav-1) is found predominately in terminally differentiated cells, such as adipocytes, endothelia and smooth muscle cells, as well as type I pneumocytes. As a main structural component of caveolae, Cav-1 is important in modulating cellular signaling. In the present study, the expression and clinical role of Cav-1 were analyzed in tumor stromal and human cancer cells, respectively. The results of previous studies have shown that the downregulation of tumor stromal Cav-1 promotes tumor survival and predicts a poor tumor prognosis, predominantly concentrating on the mechanism of the metabolism of the cancer microenvironment (according to the autophagic tumor stroma model of cancer metabolism and the reverse Warburg effect). However, contradictory results concerning the expression, clinical roles and associated mechanisms of Cav-1 have been reported. An improved understanding of Cav-1 expression in tumor stromal and cancer cells will increase knowledge with regard to the clinical value of Cav-1 and its detailed mechanisms. This review summarizes the novel data concerning the clinical values and probable mechanisms of Cav-1 expression in tumor stromal (predominantly in cancer-associated fibroblasts) and cancer cells, respectively.

Caveola-forming proteins caveolin-1 and PTRF in prostate cancer

The expression of caveola-forming proteins is dysregulated in prostate cancer. Caveolae are flask-shaped invaginations of the plasma membrane that have roles in membrane trafficking and cell signalling. Members of two families of proteins--caveolins and cavins--are known to be required for the formation and functions of caveolae. Caveolin-1, the major structural protein of caveolae, is overexpresssed in prostate cancer and has been demonstrated to be involved in prostate cancer angiogenesis, growth and metastasis. Polymerase I and transcript release factor (PTRF) is the only cavin family member necessary for caveola formation. When exogenously expressed in prostate cancer cells, PTRF reduces aggressive potential, probably via both caveola-mediated and caveola-independent mechanisms. In addition, stromal PTRF expression decreases with progression of the disease. Evaluation of caveolin-1 antibodies in the clinical setting is underway and it is hoped that future studies will reveal the mechanisms of PTRF action, allowing its targeting for therapeutic purposes.

Biochemical markers of aging for longitudinal studies in humans

Much progress has been made in the past decades in unraveling the mechanisms that are responsible for aging. The discovery that particular gene mutations in experimental species such as yeast, flies, and nematodes are associated with longevity has led to many important insights into pathways that regulate aging processes. However, extrapolating laboratory findings in experimental species to knowledge that is valid for the complexity of human physiology remains a major challenge. Apart from the restricted experimental possibilities, studying aging in humans is further complicated by the development of various age-related diseases. The availability of a set of biomarkers that really reflect underlying aging processes would be of much value in disentangling age-associated pathology from specific aging mechanisms. In this review, we survey the literature to identify promising biochemical markers of aging, with a particular focus on using them in longitudinal studies of aging in humans that entail repeated measurements on easily obtainable material, such as blood samples. Our search strategy was a 2-pronged approach, one focused on general mechanisms of aging and one including studies on clinical biomarkers of age-related diseases.

Anti-caveolin-1 antibodies as anti-prostate cancer therapeutics

Caveolae are critical cell surface structures important in coordinated cell signaling and endocytosis. One of the major proteins of caveolae is caveolin 1 (Cav-1). Cellular levels of Cav-1 are associated with cancer progression. In prostate cancer cells, levels of Cav-1 are positively correlated with tumor progression and metastasis. Cav-1 can be secreted by prostate cancer cells into the microenvironment and triggers proliferation and anti-apoptosis of the tumor and tumor endothelial cells. Clinical studies have shown increased serum Cav-1 levels in patients with poor prognosis. In tissue culture and animal model experiments, blocking secreted Cav-1 by polyclonal antibodies inhibits tumor cell growth. Cav-1 is therefore a potential therapeutic target for prostate cancer treatment. In this study, we used Cav-1 knock-out mice as hosts to produce monoclonal anti-Cav-1 antibodies. A total of 11 hybridoma cell lines were selected for their ability to produce antibodies that bound GST-Cav-1 but not GST on glutathione-coated ELISA plates. Further screening with ELISAs using GST-Cav-1 fragments on GSH-coated plates classified these antibodies into four groups: N1-31 with five antibodies binds the far N-terminus between amino acids 1 and 31; N32-80 with three antibodies binds between amino acids 32 and 80; CSD with two antibodies potentially bind the scaffolding domain (amino acids 80-101); and Cav-1-C with 1 antibody binds parts of the C-terminal half. Binding affinities (Kd) of these antibodies to soluble Cav-1 ranged from 10(-11) to 10(-8) M. Binding competition experiments revealed that these antibodies recognized a total of six different epitopes on Cav-1. Potency of these antibodies to neutralize Cav-1-mediated signaling pathways in cultured cells and in animal models will be tested. A selected monoclonal antibody will then be humanized and be further developed into a potential anti-prostate cancer therapeutic.

A genetic polymorphism in the CAV1 gene associates with the development of bronchiolitis obliterans syndrome after lung transplantation

Background

Caveolin 1 (Cav-1) is the primary structural component of cell membrane invaginations called 'caveolae'. Expression of Cav-1 is implicated in the pathogenesis of pulmonary fibrosis. Genetic polymorphisms in the CAV1 gene influence the function of Cav-1 in malignancies and associate with renal allograft fibrosis. Chronic allograft rejection after lung transplantation, called 'bronchiolitis obliterans syndrome' (BOS), is also characterised by the development of fibrosis.

In this study, we investigated whether CAV1 genotypes associate with BOS and whether Cav-1 serum levels are influenced by the CAV1 genotype and can be used as a biomarker to predict the development of BOS.

Methods

Twenty lung transplant recipients with BOS (BOS^pos), ninety without BOS (BOS^neg) and four hundred twenty-two healthy individuals donated DNA samples. Four SNPs in CAV1 were genotyped. Serial Cav-1 serum levels were measured in a matched cohort of 10 BOS^pos patients and 10 BOS^neg patients. Furthermore, single-time point Cav-1 serum levels were measured in 33 unmatched BOS^neg patients and 60 healthy controls.

Results

Homozygosity of the minor allele of rs3807989 was associated with an increased risk for BOS (odds ratio: 6.13; P = 0.0013). The median Cav-1 serum level was significantly higher in the BOS^pos patients than in the matched BOS^neg patients (P = 0.026). Longitudinal analysis did not show changes in Cav-1 serum levels over time in both groups. The median Cav-1 serum level in the group of 43 BOS^neg patients was lower than that in the healthy control group (P = 0.046).

In lung transplant recipients, homozygosity of the minor allele of rs3807989 and rs3807994 was associated with increased Cav-1 serum levels.

Conclusion

In lung transplant recipients, the CAV1 SNP rs3807989 was associated with the development of BOS and Cav-1 serum levels were influenced by the CAV1 genotype.