Genetic Variants in Caveolin-1 and RhoA/ROCK1 Are Associated with Clear Cell Renal Cell Carcinoma Risk in a Chinese Population

Caveolin-1 Regulates Cellular Metabolism: A Potential Therapeutic Target in Kidney Disease

The kidney is an energy-consuming organ, and cellular metabolism plays an indispensable role in kidney-related diseases. Caveolin-1 (Cav-1), a multifunctional membrane protein, is the main component of caveolae on the plasma membrane. Caveolae are represented by tiny invaginations that are abundant on the plasma membrane and that serve as a platform to regulate cellular endocytosis, stress responses, and signal transduction. However, caveolae have received increasing attention as a metabolic platform that mediates the endocytosis of albumin, cholesterol, and glucose, participates in cellular metabolic reprogramming and is involved in the progression of kidney disease. It is worth noting that caveolae mainly depend on Cav-1 to perform the abovementioned cellular functions. Furthermore, the mechanism by which Cav-1 regulates cellular metabolism and participates in the pathophysiology of kidney diseases has not been completely elucidated. In this review, we introduce the structure and function of Cav-1 and its functions in regulating cellular metabolism, autophagy, and oxidative stress, focusing on the relationship between Cav-1 in cellular metabolism and kidney disease; in addition, Cav-1 that serves as a potential therapeutic target for treatment of kidney disease is also described.

Discovery of Cellular RhoA Functions by the Integrated Application of Gene Set Enrichment Analysis

The small GTPase RhoA has been studied extensively for its role in actin dynamics. In this study, multiple bioinformatics tools were applied cooperatively to the microarray dataset GSE64714 to explore previously unidentified functions of RhoA. Comparative gene expression analysis revealed 545 differentially expressed genes in RhoA-null cells versus controls. Gene set enrichment analysis (GSEA) was conducted with three gene set collections: (1) the hallmark, (2) the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and (3) the Gene Ontology Biological Process. GSEA results showed that RhoA is related strongly to diverse pathways: cell cycle/growth, DNA repair, metabolism, keratinization, response to fungus, and vesicular transport. These functions were verified by heatmap analysis, KEGG pathway diagramming, and direct acyclic graphing. The use of multiple gene set collections restricted the leakage of information extracted. However, gene sets from individual collections are heterogenous in gene element composition, number, and the contextual meaning embraced in names. Indeed, there was a limit to deriving functions with high accuracy and reliability simply from gene set names. The comparison of multiple gene set collections showed that although the gene sets had similar names, the gene elements were extremely heterogeneous. Thus, the type of collection chosen and the analytical context influence the interpretation of GSEA results. Nonetheless, the analyses of multiple collections made it possible to derive robust and consistent function identifications. This study confirmed several well-described roles of RhoA and revealed less explored functions, suggesting future research directions.

Are caveolin-1 minor alleles more likely to be risk alleles in insulin resistance mechanisms in metabolic diseases?

OBJECTIVES

Obesity and insulin resistance (IR) are interrelated in a range of ways. The IR-obesity relationship is not a cause-and-effect association. Molecular biology research has made tremendous strides in discovering contributors to find this association. Genes that control adipocyte function such as caveolin-1 (CAV1); probably interact in the pathogenesis of human IR in this context. The involvement of CAV1 in glucose/lipid homeostasis is revealed and could modify the signaling of the insulin receptor. We examined the association between CAV1 and insulin signaling in modifying dyslipidemia and fat composition in overweight and obese women with a prevalent variant in the CAV1 gene.

RESULTS

Minor allele carriers were slightly older and had higher BMI (p = 0.02), FMI (p = 0.006), and VLF (p = 0.01) values; and tended to have lower total cholesterol TC (p = 0.04), low-density lipoprotein cholesterol (LDL-C) (p = 0.001) and high-density lipoprotein cholesterol (HDL-C) (p = 0.003). HOMA-IR levels predicted fat mass index (FMI) 0.47 (0.08, 0.87), visceral fat level (VFL) 0.65 (0.23, 1.07), TC 6.82 (1.76, 11.88) and HDL-C - 1.663 (- 3.11, - 0.214) only between minor allele carriers in adjusted models. (β, CI). Our results cast a new light on the IR mechanism and future studies will elucidate the clinical relevance of CAV1-IR in patients with dyslipidemia and high fat composition.

Genetic Risk and Phenotype Correlation of Primary Open-Angle Glaucoma Based on Rho-Kinase Gene Polymorphisms

Rho-associated coiled-coil kinase (ROCK) signaling can affect glaucoma risk by regulating trabecular meshwork outflow. We investigated the effect of ROCK gene polymorphism on the risks of primary open-angle glaucoma (POAG) and POAG-related phenotypes including intraocular pressure (IOP) in a Korean population. A total of 24 single-nucleotide polymorphisms (SNPs) from ROCK1 and ROCK2 were selected and genotyped for 363 POAG patients and 213 healthy controls. Among the 363 POAG patients, 282 were normal-tension glaucoma (NTG, baseline IOP ≤ 21 mmHg) and 81 were high-tension glaucoma (HTG, baseline IOP > 21 mmHg). The SNPs rs288979, rs1006881, rs35996865, rs10083915, and rs11873284 in ROCK1 (tagged to each other, r² = 1) were nominally associated with risk of HTG (OR = 0.52, p = 0.045). However, there were no SNPs that were significantly associated with the risk of NTG. In the genotype-phenotype correlation analysis, the SNPs rs2230773 and rs3771106 in ROCK2 were significantly correlated with central corneal thickness (CCT)-adjusted IOP (p = 0.024) and axial length (AXL; p = 0.024), respectively. The present data implicated the role of ROCK in POAG development, and as such, can serve as a good reference for upcoming Rho/ROCK-pathway-related studies on POAG.

Caveolin-1 rs4730751 single-nucleotide polymorphism may not influence kidney transplant allograft survival

Caveolin-1 is a protein (encoded by the CAV1 gene) supposedly harboring a protective effect against fibrosis. CAV1 rs4730751 single nucleotide polymorphism (SNP) AA genotype was initially associated with lower graft survival compared to non-AA. However, subsequent studies could not find the same effect. CAV1 rs4730751 SNP was investigated on 918 kidney donors. Multivariate Cox-model analyses were performed to evaluate risk factors for graft loss. Longitudinal changes on long-term estimated glomerular filtration rate (eGFRs) were evaluated with a linear mixed model. Histopathological findings from protocolled biopsies after 3 months post transplantation were also analyzed. Donor CAV1 rs4730751 genotyping proportions were 7.1% for AA, 41.6% for AC and 51.3% for CC. The AA genotype, compared to non-AA, was not associated with lower graft survival censored or not for death (multivariate analysis: HR = 1.23 [0.74–2.05] and HR = 1.27 [0.84–1.92]). Linear mixed model on long-term eGFRs revealed also no significant difference according to the genotype, yet we observed a trend. AA genotype was also not associated with a higher degree of fibrosis index on protocolled kidney biopsies at 3 months. To conclude, donor CAV1 rs4730751 SNP may impact on kidney transplantation outcomes, but this study could not confirm this hypothesis.

Determining association of rho kinase 1 gene polymorphisms with risk of Alzheimer's disease: a multicenter pilot study

Background

In addition to the increasing evidence for a molecular mechanism of rho kinase 1 (ROCK1) in Alzheimer's disease (AD), there are several published studies regarding the relationship between ROCK1 gene polymorphisms and neurological diseases. However, it is unknown whether there is an association between the polymorphisms of ROCK1 and AD. We sought to identify the potential association between ROCK1 gene polymorphisms and AD in the Chinese Han population.

Methods

A total of 295 patients with AD and 206 healthy controls from multiple centers were enrolled in this study. Three single-nucleotide polymorphisms (SNPs) (rs35996865, rs11873284, and rs2127958) in ROCK1 gene were analyzed using Sanger sequencing.

Results

We did not find any significant differences between AD and control groups with regards to the frequency of these three ROCK1 polymorphisms. Further, the three SNP genotype frequencies and allele frequencies did not show significant differences between patients of AD and controls in APOE4-stratified subjects (P>0.01). Additionally, the three SNPs did not show significant differences even when adopting a four-inheritance model by logistic regression.

Conclusions

This is the first multicenter pilot study to evaluate the contribution of ROCK1 genetic variance to AD risk. Our data demonstrated that the ROCK1 gene may not influence the risk of AD by interacting with APOE among Chinese Han people.

MiR-199a-3p acts as a tumor suppressor in clear cell renal cell carcinoma

OBJECTIVES

To explore the biological function and mechanism of miR-199a-3p in clear cell renal cell carcinoma (CCRCC).

METHODS

We investigated the expression of miR-199a-3p in CCRCC through quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Over expression of miR-199a-3p was performed in CCRCC cell lines, and cell growth curve, colony formation capacity, cell invasion, wound healing and cell apoptosis assay were used for investigating the roles of miR-199a-3p in CCRCC.

RESULTS

The expression of miR-199a-3p in CCRCC tissues was significantly lower than that in para-carcinoma tissues. Functional assay showed that over expression of miR-199a-3p influenced cell growth, colony formation, cell invasion, cell migration and cell apoptosis in CCRCC cell lines.

CONCLUSIONS

Our work suggested that miR-199a-3p was related to cell growth, colony formation, cell invasion, cell migration and cell apoptosis, which might act as a tumor suppressor in CCRCC.

Genetic polymorphisms in caveolin-1 associate with breast cancer risk in Chinese Han population

Caveolin-1(CAV-1) was demonstrated to be a tumor suppressor gene and be implicated in the development of breast cancer (BC). Numerous potentially functional polymorphisms in CAV-1 have been identified, but their effects on BC were not clear. This case-control study aims to evaluate the relationship between CAV-1 polymorphisms and BC risk. 560 BC patients and 583 healthy controls were enrolled in the present study, all from Chinese Han population. We detected 3 single nucleotide polymorphisms (rs3807987, rs1997623, and rs7804372) in CAV-1 using the Sequenom MassARRAY method. The association between CAV-1genotypes and BC risk was assessed in six genetic models by calculating the odds ratio (OR) and 95% confidence intervals (95% CIs) with χ2-test. The CAV-1 rs3807987 polymorphism was observed to increase the risk of BC And the A allele of rs3807987 relates to a larger tumor size (≥2cm) and lower incidence of PR-positive BC while the AA genotype of rs7804372 associates with a higher ER and Her-2 positive rate among BC patients. In addition, Ars1997623Grs3807987Trs7804372 haplotype was linked to a decreased risk of BC (OR =0.64, 95%CI=0.44-0.93), whereas Crs1997623Ars3807987Trs7804372 haplotype was related to an increased BC risk (OR =1.74, 95%CI=1.04-2.92). Our study suggests that CAV-1 rs3807987 can increase the BC risk among Chinese Han women. And the rs3807987 and rs7804372 in CAV-1 may serve as predictors for prognosis of BC.

The influence of caveolin-1 gene polymorphisms on hepatitis B virus-related hepatocellular carcinoma susceptibility in Chinese Han population: A case-control study

This study aimed to explore the genetic association of polymorphisms in caveolin-1 gene (CAV1) with hepatitis B virus-related hepatocellular carcinoma (HBV-related HCC) susceptibility in a Chinese Han population.The genotyping of polymorphism was conducted using polymerase chain reaction-restriction fragment length polymorphism method. Whether the genotype distribution of polymorphisms in the healthy controls was consistent with Hardy-Weinberg equilibrium (HWE) was detected. The genotype and allele frequency difference between the 2 groups was compared by chi-square test. Odds ratio (OR) and 95% confidence interval (95% CI) were calculated to show the relative risk of HCC which resulted from genetic variants in CAV1. Moreover, the linkage disequilibrium of CAV1 polymorphisms was analyzed by Haploview.The AG genotype and A allele of rs1049334 showed significantly higher frequency in HCC patients than that of chronic HBV patients and the healthy controls (P < .05); so their carriage obviously increased the susceptibility to HBV-related HCC, irrespective of the fact whether individuals were infected with hepatitis B virus or not (AG vs GG: OR 1.958, 95% CI 1.050-3.650, OR 1.899, 95% CI 1.034-3.487; A vs G: OR 1.667, 95% CI 1.033-2.689, OR 1.777, 95% CI 1.103-2.863). Additionally, A-G haplotype of rs3807989-rs1049334 showed the protective role for HBV-related HCC (OR 0.102, 95% CI 0.035-0.293; OR 0.135, 95% CI 0.046-0.395).CAV1 rs1049334 polymorphism is significantly associated with the occurrence risk of HBV-related HCC, and the interaction of polymorphisms should not be neglected.

Rho kinase proteins display aberrant upregulation in vascular tumors and contribute to vascular tumor growth

BACKGROUND

The serine/threonine protein kinases ROCK1 and 2 are key RhoA-mediated regulators of cell shape and cytoskeletal dynamics. These proteins perform multiple functions in vascular endothelial cell physiology and are attractive targets for cancer therapy based on their roles as oncogenes and metastatic promoters. Given their critical functions in both of these processes, we hypothesized that molecular targeting of ROCK proteins would be exceedingly effective against vascular tumors such as hemangiomas and angiosarcomas, which are neoplasms composed of aberrant endothelial cells.

METHODS

In this study, we compared ROCK1 and 2 protein expression in a large panel of benign and malignant vascular tumors to that of normal vasculature. We then utilized shRNA technology to knockdown the expression of ROCK1 and 2 in SVR tumor-forming vascular cells, and evaluated tumor size and proliferation rate in a xenograft model. Finally, we employed proteomics and metabolomics to assess how knockdown of the ROCK paralogs induced alterations in protein expression/phosphorylation and metabolite concentrations in the xenograft tumors.

RESULTS

Our findings revealed that ROCK1 was overexpressed in malignant vascular tumors such as hemangioendotheliomas and angiosarcomas, and ROCK2 was overexpressed in both benign and malignant vascular tumors including hemangiomas, hemangioendotheliomas, hemangiopericytomas, and angiosarcomas. shRNA-mediated knockdown of ROCK2, but not ROCK1, in xenograft vascular tumors significantly reduced tumor size and proliferative index compared to control tumors. Proteomics and metabolomics analysis of the xenograft tumors revealed both overlapping as well as unique roles for the ROCK paralogs in regulating signal transduction and metabolite concentrations.

CONCLUSIONS

Collectively, these data indicate that ROCK proteins are overexpressed in diverse vascular tumors and suggest that specific targeting of ROCK2 proteins may show efficacy against malignant vascular tumors.

Possible Gender-Related Modulation by the ROCK1 Gene in Colorectal Cancer Susceptibility

AIM

In view of accumulating evidence supporting a pivotal role of the Rho/ROCK pathway in cancer, we investigated Rho-kinase polymorphisms as potential susceptibility factors in colorectal cancer (CRC) in a representative sample of the Italian population.

METHODS

DNA obtained from the peripheral blood samples of 137 CRC patients and 141 healthy controls was genotyped for four ROCK1 (rs35996865; rs73963110; rs2127958; rs288980) and five ROCK2 (rs12692437; rs7563468; rs35768389; rs17463896; rs16857265) selected single nucleotide polymorphisms.

RESULTS

None of the allelic variants of the nine selected markers was associated with the occurrence of CRC or with the development of regional lymph node metastasis. By contrast, the ROCK1 rs35996865 G variant allele was significantly more frequent in male patients (p = 0.028) than in the control group.

CONCLUSION

This finding is, at present, the first that points to a possible gender-related modulation by the ROCK1 gene in CRC susceptibility.