Caveolin 1 protein expression in renal cell carcinoma predicts survival

Membranous Overexpression of Fibronectin Predicts Microvascular Invasion and Poor Survival Outcomes in Patients with Hepatocellular Carcinoma

Background/Aims

Fibronectin (FN) has recently been identified as being overexpressed in patients with hepatocellular carcinoma (HCC) and deemed a promising biomarker of vascular invasion. The aim of this study was to examine the patterns of FN expression in HCC cells and their clinicopathological significance, such as their association with vascular invasion and angiogenesis patterns.

Methods

Immunohistochemical analysis of FN was conducted using tissue microarrays from 258 surgically resected HCCs and matched nontumorous liver tissues. Three distinct FN expression patterns were observed: cytoplasmic, membranous, and sinusoidal. Moderate or strong expression was considered FN-positive.

Results

Cytoplasmic or sinusoidal FN expression was significantly more common in HCC cells than in the adjacent liver tissue (p<0.001). FN expression was detected in the membranes of HCC cells and absent in nonneoplastic hepatocytes (p<0.001). Overall survival and disease-free survival in patients with HCC cells with membranous FN expression were significantly shorter than those in patients without membranous FN expression. Membranous FN expression in HCC was significantly associated with high serum alpha-fetoprotein (AFP) and protein induced by vitamin K absence-II (PIVKA-II) levels, infiltrative gross type, poor Edmondson-Steiner grade, major vessel invasion, microvascular invasion, macrotrabecular massive subtype, advanced T stage, and vessel-encapsulating tumor cluster pattern. Sinusoidal pattern of FN expression in HCC was significantly associated with high serum AFP and PIVKA-II levels, infiltrative gross type, large tumor size, microvascular invasion, macrotrabecular massive subtype, and vessel-encapsulating tumor cluster patterns.

Conclusions

Evaluating FN expression in HCC cells may be useful for identifying aggressive cases of HCC with vascular invasion via biopsy.

Evaluation of Gas 6 as a Prognostic Marker in Papillary Renal Cell Carcinoma

INTRODUCTION

Growth arrest-specific protein 6 (Gas 6) is a ligand that plays a role in proliferation and migration of cells. For several tumor entities, high levels of Gas 6 are associated with poorer survival. We examined the prognostic role of Gas 6 in renal cell carcinoma (RCC), especially in papillary RCC (pRCC), which is still unclear.

METHODS

The patients' sample collection is a joint collaboration of the PANZAR consortium. Patients' medical history and tumor specimens were collected from n = 240 and n = 128 patients with type 1 and 2 pRCC, respectively. Expression of Gas 6 was determined by immunohistochemistry.

RESULTS

In total, Gas 6 staining was evaluable in 180 of 240 type 1 and 110 of 128 type 2 pRCC cases. Kaplan-Meier analysis disclosed no significant difference in 5-year overall survival for all pRCC nor either subtype. Also, Gas+ and Gas- groups did not significantly differ in any tumor or patient characteristics.

CONCLUSION

Gas 6 was not found to be an independent prognostic marker in pRCC. Future studies are warranted to determine if Gas 6 plays a role as prognostic marker or therapeutic target in pRCC.

Discovery of pathway-independent protein signatures associated with clinical outcome in human cancer cohorts

Proteomic data provide a direct readout of protein function, thus constituting an information-rich resource for prognostic and predictive modeling. However, protein array data may not fully capture pathway activity due to the limited number of molecules and incomplete pathway coverage compared to other high-throughput technologies. For the present study, our aim was to improve clinical outcome prediction compared to published pathway-dependent prognostic signatures for The Cancer Genome Atlas (TCGA) cohorts using the least absolute shrinkage and selection operator (LASSO). RPPA data is particularly well-suited to the LASSO due to the relatively low number of predictors compared to larger genomic data matrices. Our approach selected predictors regardless of their pathway membership and optimally combined their RPPA measurements into a weighted risk score. Performance was assessed and compared to that of the published signatures using two unbiased approaches: 1) 10 iterations of threefold cross-validation for unbiased estimation of hazard ratio and difference in 5-year survival (by Kaplan-Meier method) between predictor-defined high and low risk groups; and 2) a permutation test to evaluate the statistical significance of the cross-validated log-rank statistic. Here, we demonstrate strong stratification of 445 renal clear cell carcinoma tumors from The Cancer Genome Atlas (TCGA) into high and low risk groups using LASSO regression on RPPA data. Median cross-validated difference in 5-year overall survival was 32.8%, compared to 25.2% using a published receptor tyrosine kinase (RTK) prognostic signature (median hazard ratios of 3.3 and 2.4, respectively). Applicability and performance of our approach was demonstrated in three additional TCGA cohorts: ovarian serous cystadenocarcinoma (OVCA), sarcoma (SARC), and cutaneous melanoma (SKCM). The data-driven LASSO-based approach is versatile and well-suited for discovery of new protein/disease associations.

Growth Arrest-Specific 6 in Chromophobe Renal Cell Carcinoma

BACKGROUND

Overexpression of tumor-associated growth arrest-specific protein 6 (Gas6) is found in many tumor entities. The prognostic value of Gas6 in renal cell carcinoma (RCC), especially in non-clear cell RCC, is still unclear.

AIM

The aim of the study was to evaluate the prognostic impact of Gas6 expression in a large cohort of patients with chromophobe RCC (chRCC).

MATERIAL AND METHODS

Patients who underwent renal surgery due to chRCC were retrospectively evaluated. Tumor specimens were analyzed for Gas6 expression by immunohistochemistry.

RESULTS

Eighty-one chRCC patients were eligible for analysis; of these, 24 (29.6%) patients were positive for Gas6. No significant associations were found for Gas6 expression and clinical attributes in patients with chRCC. The Kaplan-Meier analysis revealed no differences in 5-year overall survival for Gas6- compared to Gas6+ (89.6% vs. 100.0%; p = 0.288) tumors.

CONCLUSION

In chRCC, Gas6 expression is not associated with survival and other parameters of aggressiveness. Due to the rare incidence of chRCC, further studies with larger cohorts are warranted.

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.

Review of Prognostic Expression Markers for Clear Cell Renal Cell Carcinoma

Context: The number of prognostic markers for clear cell renal cell carcinoma (ccRCC) has been increasing regularly over the last 15 years, without being integrated and compared. Objective: Our goal was to perform a review of prognostic markers for ccRCC to lay the ground for their use in the clinics. Evidence Acquisition: PubMed database was searched to identify RNA and protein markers whose expression level was reported as associated with survival of ccRCC patients. Relevant studies were selected through cross-reading by two readers. Evidence Synthesis: We selected 249 studies reporting an association with prognostic of either single markers or multiple-marker models. Altogether, these studies were based on a total of 341 distinct markers and 13 multiple-marker models. Twenty percent of these markers were involved in four biological pathways altered in ccRCC: cell cycle, angiogenesis, hypoxia, and immune response. The main genes (VHL, PBRM1, BAP1, and SETD2) involved in ccRCC carcinogenesis are not the most relevant for assessing survival. Conclusion: Among single markers, the most validated markers were KI67, BIRC5, TP53, CXCR4, and CA9. Of the multiple-marker models, the most famous model, ClearCode34, has been highly validated on several independent datasets, but its clinical utility has not yet been investigated. Patient Summary: Over the years, the prognosis studies have evolved from single markers to multiple-marker models. Our review highlights the highly validated prognostic markers and multiple-marker models and discusses their clinical utility for better therapeutic care.

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.

CircAKT1 acts as a sponge of miR-338-3p to facilitate clear cell renal cell carcinoma progression by up-regulating CAV1

Circular RNAs (CircRNAs) have become a research focus for their important implication in tumorigenesis and cancer progression. This study intends to observe the function of circAKT1 in clear cell renal cell carcinoma (ccRCC) and its underlying molecular mechanism. In the present study, we confirmed the up-regulation of circAKT1 in ccRCC tissues and cells. High circAKT1 expression was positively associated with TNM stage, lymph node metastasis and predicted an adverse prognosis. Functionally, knockdown of circAKT1 suppressed cell proliferation, colony formation, migration, invasion and EMT in vitro. Mechanistic analysis uncovered that circAKT1 could act as a sponge for miR-338-3p to prevent the degradation of caveolin-1 (CAV1). Interestingly, the anti-neoplastic effect of circAKT1 knockdown on ccRCC was abated due to miR-338-3p down-regulation or CAV1 overexpression. To summarize, circAKT1 facilitated ccRCC progression at least partly by sequestering miR-338-3p to up-regulate CAV1 expression. Our findings raised the possibility of exploiting circAKT1 as a potential prognostic biomarker and therapeutic target in ccRCC.

Expression and clinical significance of Caveolin-1 in prostate Cancer after transurethral surgery

Background

Prostate cancer is a common malignancy of the male genitourinary system that occurs worldwide. The current research aims to investigate caveolin-1 expression in prostate cancer tissue and its relationship with pathological grade, clinical pathologic staging, and preoperative prostate-specific antigen (PSA) levels.

Methods

From January 2012 to December 2014, samples from 47 patients with prostate cancer who had received transurethral prostatic resection (TURP) and 20 patients with benign prostatic hyperplasia were collected at the First Affiliated Hospital of Guangxi Medical University. Caveolin-1 was detected by streptavidin-perosidase (SP) immunohistochemical staining in pathological tissue slices. The results were statistically analyzed for pathological grade, clinical stage, and preoperative PSA level.

Results

The expression of caveolin-1 was significantly higher in prostate cancer samples than in benign prostatic hyperplasia samples (P < 0.05), and caveolin-1 expression was significantly different among the pathological grades of poorly, moderately and well-differentiated prostate cancer (P < 0.05). The difference in caveolin-1 expression was significant for different clinical stages (T1-T2 and T3-T4) of prostate cancer (P < 0.05). The difference in caveolin-1 expression was not significant among samples with different preoperative PSA levels (0–10, 10–100 and > 100 μg/L) (P > 0.05).

Conclusions

Caveolin-1 is closely related to the pathological grade and clinical stage of prostate cancer after transurethral surgery, and it may be a novel tumor marker for prostate cancer. The expression of caveolin-1 is not associated with preoperative serum PSA levels.

Renal carcinoma/kidney progenitor cell chimera organoid as a novel tumorigenesis gene discovery model

Three-dimensional (3D) organoids provide a new way to model various diseases, including cancer. We made use of recently developed kidney-organ-primordia tissue-engineering technologies to create novel renal organoids for cancer gene discovery. We then tested whether our novel assays can be used to examine kidney cancer development. First, we identified the transcriptomic profiles of quiescent embryonic mouse metanephric mesenchyme (MM) and of MM in which the nephrogenesis program had been induced ex vivo. The transcriptome profiles were then compared to the profiles of tumor biopsies from renal cell carcinoma (RCC) patients, and control samples from the same kidneys. Certain signature genes were identified that correlated in the developmentally induced MM and RCC, including components of the caveolar-mediated endocytosis signaling pathway. An efficient siRNA-mediated knockdown (KD) of Bnip3, Gsn, Lgals3, Pax8, Cav1, Egfr or Itgb2 gene expression was achieved in mouse RCC (Renca) cells. The live-cell imaging analysis revealed inhibition of cell migration and cell viability in the gene-KD Renca cells in comparison to Renca controls. Upon siRNA treatment, the transwell invasion capacity of Renca cells was also inhibited. Finally, we mixed E11.5 MM with yellow fluorescent protein (YFP)-expressing Renca cells to establish chimera organoids. Strikingly, we found that the Bnip3-, Cav1- and Gsn-KD Renca-YFP+ cells as a chimera with the MM in 3D organoid rescued, in part, the RCC-mediated inhibition of the nephrogenesis program during epithelial tubules formation. Altogether, our research indicates that comparing renal ontogenesis control genes to the genes involved in kidney cancer may provide new growth-associated gene screens and that 3D RCC-MM chimera organoids can serve as a novel model with which to investigate the behavioral roles of cancer cells within the context of emergent complex tissue structures.

Editor’s Choice: Chimeras between embryonic kidney cells and renal carcinoma cells serve as a novel model to assay the roles of co-regulated genes in kidney development and renal carcinogenesis.

Enhanced expression of caveolin-1 possesses diagnostic and prognostic value and promotes cell migration, invasion and sunitinib resistance in the clear cell renal cell carcinoma

Caveolin-1 (CAV1) has been identified to be up-regulated in many cancers, including clear cell renal cell carcinoma (ccRCC). However, its potential function is still unclear in ccRCC. In this study, we demonstrated that CAV1 was frequently overexpressed in renal cell carcinoma tissues and cells, and was significantly associated with various clinicopathological parameters. In addition, high CAV1 expression was associated with poor disease-free survival (DFS) rate and could serve as a useful diagnostic indicator in ccRCC patients with different clinicopathological stages. Functional experiments demonstrated that CAV1 knockdown inhibited cell migration and invasion, whereas overexpression of CAV1 promoted cell migration and invasion in ccRCC. Moreover, CAV1 expression was up-regulated in sunitinib-resistant renal cancer cell lines, and its overexpression promoted sunitinib resistance. In general, our results confirm that CAV1 plays an important role in the metastasis of kidney cancer and induces sunitinib resistance, so CAV1 function suppression may become a promising clinical treatment strategy during renal cell carcinoma metastasis and sunitinib resistance.

Clear Cell Renal Cell Carcinoma is linked to Epithelial-to-Mesenchymal Transition and to Fibrosis

Clear cell renal cell carcinoma (ccRCC) represents the most common type of kidney cancer with high mortality in its advanced stages. Our study aim was to explore the correlation between tumor epithelial-to-mesenchymal transition (EMT) and patient survival. Renal biopsies of tumorous and adjacent nontumorous tissue were taken with a 16 g needle from our patients (n = 26) undergoing partial or radical nephrectomy due to ccRCC RNA sequencing libraries were generated using Illumina TruSeq® Access library preparation protocol and TruSeq Small RNA library preparation kit. Next generation sequencing (NGS) was performed on Illumina HiSeq2500. Comparative analysis of matched sample pairs was done using the Bioconductor Limma/voom R-package. Liquid chromatography-tandem mass spectrometry and immunohistochemistry were applied to measure and visualize protein abundance. We detected an increased generic EMT transcript score in ccRCC Gene expression analysis showed augmented abundance of AXL and MMP14, as well as down-regulated expression of KL (klotho). Moreover, microRNA analyses demonstrated a positive expression correlation of miR-34a and its targets MMP14 and AXL Survival analysis based on a subset of genes from our list EMT-related genes in a publicly available dataset showed that the EMT genes correlated with ccRCC patient survival. Several of these genes also play a known role in fibrosis. Accordingly, recently published classifiers of solid organ fibrosis correctly identified EMT-affected tumor samples and were correlated with patient survival. EMT in ccRCC linked to fibrosis is associated with worse survival and may represent a target for novel therapeutic interventions.

PD-L2: A prognostic marker in chromophobe renal cell carcinoma?

In the context of cancer immunotherapy, PD-1 as well as PD-L1 has been widely studied in renal cell carcinoma (RCC). PD-1 and PD-L1 play a significant role as prognostic markers in clear cell renal cell carcinoma. In contrast, little is known about PD-L2 expression patterns in RCC, especially in rarer subtypes. The aim of this study was to evaluate the prevalence, distribution and prognostic impact of PD-L2 expression in chromophobe (ch)RCC. Eighty-one patients who underwent renal surgery due to chRCC were retrospectively evaluated. Tumor specimens were analyzed for PD-L2 expression by immunohistochemistry. Expression data were associated with clinicopathological parameters and overall survival (OS). Twenty-three (28.4%) patients showed a PD-L2 > median (PD-L2 high) staining intensity. No significant association between clinicopathological parameters and PD-L2 expression was identified. A significant difference between 5- and 10-year OS in dependence of PD-L2 expression was found (PD-L2 low 96.4 and 87.7% vs. PD-L2 high 87.1 and 56%; log rank, p = 0.029). However, in multivariate analysis PD-L2 expression failed to be proofed as an independent prognostic factor. In conclusion, to our knowledge this is the first study evaluating the prognostic impact of PD-L2 in a considerably large cohort of chRCC. Our results showed a significant diminished OS in dependence of PD-L2 expression. This implicates that PD-L2 might play a role as prognostic marker in chRCC demanding further evaluation.

The Evaluation and Comparing of Cytotoxic Effects of Ferula gummosa Gum, Scutellaria lindbergii, Kelussia odoratissima and Artemisia kopetdaghensis Extracts on ACHN Cell Line

Renal cell carcinoma (RCC) is one of most fatal cancers. In most patients it is resistant to chemotherapy. Ferula gummosa gum, Scutellaria lindbergii, Kelussia odoratissima, and Artemisia kopetdaghensis are herbs about which there are some cytotoxic activity reports. In this study, cytotoxic and apoptotic activity of these four extracts on RCC cell line (ACHN) were evaluated and compared (ACHN) cells were treated with different concentrations of herbal extracts (15-500 μg/mL). Cell proliferation was determined after 24, 48, and 72 h. by MTT assay. Apoptotic cells were determined using PI staining of DNA fragmentation by flow cytometry. Cell viability decreased with all herbal extracts in ACHN cells by 24, 48, and 72 h. as compared with control. Extracts induced a sub-G1 peak in flow cytometry histogram of treated cells indicating apoptotic cell death is involved in extracts induced-toxicity. Results imply that four herbal extracts inhibit the growth of ACHN cells as a concentration- and time-dependent manner. Also, results show that apoptosis is proposed as the possible mechanism of action. So, four herbal extracts could be considered as good anticancer agents in RCC after further studies.

Is plasma caveolin-1 level a prognostic biomarker in metastatic pancreatic cancer?

BACKGROUND/AIMS

To evaluate the prognostic significance of plasma caveolin (CAV)-1 and its association with survival and treatment response rates in metastatic pancreatic cancer (MPC).

PATIENTS AND METHODS

Plasma samples were prospectively collected from 41 patients with newly diagnosed MPC. Moreover, plasma samples were collected from 48 patients with chronic pancreatitis and 41 healthy individuals (control groups) for assessing Cav-1 levels. Plasma Cav-1 levels were evaluated at baseline and after three cycles of chemotherapy in the patients with MPC.

RESULTS

The median Cav-1 level was 13.8 ng/mL for the patients with MPC and 12.2 ng/mL for healthy individuals (P = 0.009). The Cav-1 cut-off level was calculated as 11.6 ng/mL by using the receiver operating characteristic curve. The median overall survival and progression-free survival rates were 5 and 2.4 months, respectively, for participants with a high basal plasma Cav-1 level; the corresponding values were 10.5 and 9.4 months for participants with a low plasma Cav-1 level (P = 0.011 and P= 0.003, respectively). Of the 41 patients with MPC, 23 completed at least three cycles of chemotherapy. The median Cav-1 level was 13 ng/mL for post-treatment MPC (r2: 0.917; P= 0.001). High basal plasma caveolin-1 level have continued to remain at high levels even after chemotherapy, showing a trend toward worse response rates (P = 0.086).

CONCLUSION

High basal plasma Cav-1 levels seem to be associated with poor survival and tend to yield worse therapeutic outcomes in patients with MPC. This study is the first to evaluate the prognostic significance of plasma Cav-1 levels as a prognostic factor in patients with MPC. However, larger prospective clinical trials are warranted.

c-Met in chromophobe renal cell carcinoma

c-Met plays a role as a prognostic marker in clear cell renal cell carcinoma. In addition, recently the tyrosine kinase inhibitor cabozantinib targeting c-Met was approved for the treatment of advanced renal cell carcinoma (RCC). In contrast to clear cell RCC, little is known about c-Met expression patterns in rarer RCC subtypes. The aim of this study was to evaluate the prevalence, distribution and prognostic impact of c-Met expression on chromophobe (ch)RCC. Patients who underwent renal surgery due to chRCC were retrospectively evaluated. Tumor specimens were analyzed for c-Met expression by immunohistochemistry. Expression data were associated with clinicopathological parameters including patient survival. Eighty-one chRCC patients were eligible for analysis. Twenty-four (29.6%) patients showed a high c-Met expression (c-Met^high, staining intensity higher than median). Our results showed an association between c-Met^high expression and the existence of lymph node metastasis (p = 0.007). No further significant clinicopathological associations with c-Met were identified, also regarding c-Met expression and overall survival. In conclusion, to our knowledge this is the first study evaluating the prognostic impact of c-Met in a considerably large cohort of chRCC. High c-Met expression is associated with the occurrence of lymph node metastasis. This indicates that c-Met might be implicated into metastatic progression in chRCC.

Calretinin but not caveolin-1 correlates with tumour histology and survival in malignant mesothelioma

Malignant mesothelioma (MM) continues to be a disease with poor prognosis and limited treatment options. Calretinin and caveolin-1 expression by tumour in MM have recently been described to be associated with tumour histology, differentiation and consequently survival. In a large, well annotated cohort, we studied both of these biomarkers and explored their association with clinicopathological parameters and survival. A retrospective search of patients with MM who underwent surgery at the Austin Hospital in Melbourne, Australia, was conducted. Clinical history and outcome data were retrieved from patient records. Tissue microarrays (TMAs) were constructed and stained for calretinin and caveolin-1. 'H scores' were derived, taking intensity and distribution of staining, and the cohort was dichotomised using median values for both markers. In the 329 patients evaluated, median age was 67 years. Males outnumbered females by 5:1. Epithelioid histology 202/319 (62.9%) was the most common, followed by biphasic 72/319 (21.8%) and sarcomatoid 45/319 (13.6%); histology could not be confirmed in 10 patients. Calretinin expression was detected in 246 of the 324 (76%) evaluable patients and high expression was associated with epithelioid histology (p < 0.0001). Caveolin-1 was expressed in 298 (94%) of 317 evaluable patients which was much higher compared to its expression in a cohort of lung adenocarcinomas (8/58, 13.7%). However, no association with histology was found (p = 0.409). When taken as a continuous variable, calretinin expression was found to be an independent predictor of survival, alongside histology, neutrophil-lymphocyte ratio, weight loss and stage. No prognostic value was demonstrable for caveolin-1 expression and calretinin/caveolin-1 ratio. There was no relationship between calretinin and caveolin-1 expression. In MM, increased calretinin expression is associated with epithelioid histology and better survival. Caveolin-1 is a sensitive MM marker and is expressed in a high proportion of cases but lacks association with histology and survival.

Diagnostic utility of vimentin, CD117, cytokeratin-7 and caveolin-1 in differentiation between clear cell renal cell carcinoma, chromophobe renal cell carcinoma and oncocytoma

Overlapping morphological characteristics pose some difficulties in making a proper diagnosis of clear cell renal cell carcinoma (CCRCC), chromophobe renal cell carcinoma (ChRCC), and oncocytoma, on the basis of hematoxylin-eosin-stained tissue sections. Our objective was to find out a fast, reliable panel of immunohistochemical markers for differentiation between them. The study was carried out on 55 selected renal tumor specimens: 36 cases of CCRCC, seven cases of ChRCC, and 12 cases of oncocytoma. The specimens were stained immunohistochemically for vimentin, CD117, cytokeratin (CK)7, and caveolin (Cav)-1. Sensitivity and specificity for each marker were calculated. Vimentin expression was exclusively observed in CCRCC (100%) and negative in ChRCC and oncocytoma. CD117 was absent in CCRCC, but it was strongly expressed in ChRCC (85.5%) and oncocytoma (91.7%), with high sensitivity and specificity. Most CCRCCs and oncocytomas were negative for CK7 (91.7% and 83.3%, respectively), in contrast to ChRCCs, which showed positivity in nearly 86% of the cases. Good sensitivity and specificity were calculated for CK7 in differentiating studied oncocytic tumors. Cav-1 was positive in ~78% of the CCRCCs and in all ChRCCs, whereas the vast majority of oncocytomas were negative. So the immunoprofile of CCRCC was vimentin⁺/CD117^-/CK7^-/Cav-1^±, ChRCC was vimentin^-/CD117⁺/CK7⁺/Cav-1⁺, and oncocytoma was vimentin^-/CD117⁺/CK7^±/Cav-1^-. So, by using combination of four markers (vimentin, CD117, CK7, and Cav-1), we achieved excellent sensitivity and specificity for differential diagnosis of CCRCC, ChRCC and oncocytoma.

miRNA-target network reveals miR-124as a key miRNA contributing to clear cell renal cell carcinoma aggressive behaviour by targeting CAV1 and FLOT1

Clear cell renal cell carcinoma (ccRCC) is an aggressive tumor with frequent metastatic rate and poor survival. Integrated analyses allow understanding the interplay between different levels of molecular alterations.

We integrated miRNA and gene expression data from 458 ccRCC and 254 normal kidney specimens to construct a miRNA-target interaction network.

We identified the downregulated miR-124-3p, -30a-5p and -200c-3p as the most influential miRNAs in RCC pathogenesis.miR-124-3p and miR-200c-3p expression showed association with patient survival, miR-30a-5p was downregulated in metastases compared to primary tumors. We used an independent set of 87 matched samples for validation. We confirmed the functional impact of these miRNAs by in vitro assays. Restoration of these miRNAs reduced migration, invasion and proliferation. miR-124-3p decreased the S phase of cell cycle, as well. We compared transcriptome profiling before and after miRNA overexpression, and validated CAV1 and FLOT1 as miR-124-3p targets. Patients with higher CAV1 and FLOT1 had lower miR-124-3p expression and shorter overall survival.

We hypothesize that these three miRNAs are fundamental contributing to ccRCC aggressive/metastatic behavior; and miR-124-3p especially has a key role through regulating CAV1 and FLOT1 expression. Restoration of the levels of these miRNAs could be considered as a potential therapeutic strategy for ccRCC.

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.

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

Background

The RhoA/ROCK pathway and Caveolin-1 (Cav-1) participate in the process of tumorigenesis in numerous types of cancer. Up-regulation of RhoA/ROCK and Cav-1 expression is considered to be associated with the development and progression of clear cell renal cell carcinoma (ccRCC). We investigated the association between genetic variations of RhoA/ROCK and Cav-1 and the risk of ccRCC in the Chinese population.

Methods

Between May 2004 and March 2014, a total of 1,248 clear cell renal cell carcinoma cases and 1,440 cancer-free controls were enrolled in this hospital-based case-control study. Nine SNPs in RhoA/ROCK and Cav-1 were genotyped using the TaqMan assay.

Result

We found two SNPs (Cav-1 rs1049334 and ROCK1 rs35996865) were significantly associated with the increasing risk of ccRCC (P = 0.002 and P < 0.001 respectively). The analysis of combined risk alleles revealed that patients with 2–4 risk alleles showed a more remarkable growth of ccRCC risk than the patients with 0–1 risk alleles(OR = 1.66, 95%CI = 1.31–2.11, P < 0.001). Younger subjects (P = 0.001, OR = 1.83, 95%CI = 1.30–2.57), higher weight subjects (P = 0.001, OR = 1.76, 95%CI = 1.25–2.47), female subjects (P = 0.007, OR = 1.75, 95% CI = 1.17–2.62), nonsmokers (P < 0.001, OR = 1.67, 95%CI = 1.26–2.23), drinkers (P = 0.025, OR = 1.75, 95% CI = 1.07–2.85), subjects with hypertension (P = 0.025, OR = 1.75, 95% CI = 1.07–2.85) and diabetes (P = 0.026, OR = 4.31, 95% CI = 1.19–15.62) showed a stronger association between the combined risk alleles and the risk of ccRCC by using the stratification analysis. Furthermore, we observed higher Cav-1 mRNA levels in the presence of the rs1049334 A allele in normal renal tissues.

Conclusion

Our results indicate that the two SNPs (Cav-1 rs1049334 and ROCK1 rs35996865) and genotypes with a combination of 2–4 risk alleles were associated with the risk of ccRCC. The functional SNP rs1049334 may affect the risk of ccRCC by altering the expression of Cav-1 and the relevance between the risk effects and the functional impact of this polymorphism needs further validation.

Loss of stromal caveolin-1 expression in colorectal cancer predicts poor survival

AIM: To investigate the clinicopathological significance and prognostic value of caveolin-1 (CAV-1) in both tumor and stromal cells in colorectal cancer (CRC).

METHODS: A total of 178 patients with CRC were included in this study. The correlation between CAV-1 expression and clinicopathologic features and survival was studied.

RESULTS: CAV-1 expression was detected in tumor and stromal cells. The expression of stromal CAV-1 was closely associated with histological type (P = 0.022), pathologic tumor-node-metastasis stage (P = 0.047), pathologic N stage (P = 0.035) and recurrence (P = 0.000). However, tumor cell CAV-1 did not show any correlation with clinical parameters. Additionally, the loss of stromal CAV-1 expression was associated with shorter disease-free survival (P = 0.000) and overall survival (P = 0.000). Multivariate analysis revealed that the loss of stromal CAV-1 expression was an independent prognostic factor for both overall survival (P = 0.014) and disease-free survival (P = 0.006).

CONCLUSION: The loss of stromal CAV-1 expression in CRC was associated with poor prognosis and could be a prognostic factor for CRC patients.

Clinical and molecular prognostic and predictive biomarkers in clear cell renal cell cancer

ABSTRACT 

The natural history of clear cell renal cell cancer is highly unpredictable with various progressors and with populations where small renal masses may be accompanied by metastatic disease. Currently, there is a critical need to determine patient risk and optimize treatment regimes. For these patients, molecular markers may offer significant information in terms of prognostic and predictive values, as well as determination of valid therapeutic targets. Until now, only a few of the many identified clear cell renal cell cancer biomarkers have been clinically validated in large cohorts. And only several biomarkers are integrated in predictive or prognostic models. Therefore, a large cohesive effort is required to advance the field of clear cell renal cell cancer prognostic biomarkers through systematic discovery, verification, validation and clinical implementation.

TRPM3 and miR-204 establish a regulatory circuit that controls oncogenic autophagy in clear cell renal cell carcinoma

Autophagy promotes tumor growth by generating nutrients from the degradation of intracellular structures. Here we establish, using shRNAs, a dominant-negative mutant, and a pharmacologic inhibitor, mefenamic acid (MFA), that the Transient Receptor Potential Melastatin 3 (TRPM3) channel promotes the growth of clear cell renal cell carcinoma (ccRCC) and stimulates MAP1LC3A (LC3A) and MAP1LC3B (LC3B) autophagy. Increased expression of TRPM3 in RCC leads to Ca(2+) influx, activation of CAMKK2, AMPK, and ULK1, and phagophore formation. In addition, TRPM3 Ca(2+) and Zn(2+) fluxes inhibit miR-214, which directly targets LC3A and LC3B. The von Hippel-Lindau tumor suppressor (VHL) represses TRPM3 directly through miR-204 and indirectly through another miR-204 target, Caveolin 1 (CAV1).

Caveolin-1 in oral squamous cell carcinoma microenvironment: an overview

Caveolin-1 plays an important role in the pathogenesis of oncogenic cell transformation, tumorigenesis, and metastasis. Increased expression of caveolin-1 in an array of tumors has confirmed its value in prognosis. It has been established that oxidative stress is the main cause for loss of stromal caveolin-1 via autophagy in the tumor microenvironment. In this overview, we attempt to abridge the relationship between caveolin-1 and oral squamous cell carcinoma, taking all the established theories into consideration.

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.

Caveolin-1 is required for kinase suppressor of Ras 1 (KSR1)-mediated extracellular signal-regulated kinase 1/2 activation, H-RasV12-induced senescence, and transformation

The molecular scaffold kinase suppressor of Ras 1 (KSR1) regulates the activation of the Raf/MEK/extracellular signal-regulated kinase (ERK) signal transduction pathway. KSR1 disruption in mouse embryo fibroblasts (MEFs) abrogates growth factor-induced ERK activation, H-Ras(V12)-induced replicative senescence, and H-Ras(V12)-induced transformation. Caveolin-1 has been primarily described as a major component of the coating structure of caveolae, which can serve as a lipid binding adaptor protein and coordinates the assembly of Ras, Raf, MEK, and ERK. In this study, we show that KSR1 interacts with caveolin-1 and is responsible for MEK and ERK redistribution to caveolin-1-rich fractions. The interaction between KSR1 and caveolin-1 is essential for optimal activation of ERK as a KSR1 mutant unable to interact with caveolin-1 does not efficiently mediate growth factor-induced ERK activation at the early stages of pathway activation. Furthermore, abolishing the KSR1-caveolin-1 interaction increases growth factor demands to promote H-Ras(V12)-induced proliferation and has adverse effects on H-Ras(V12)-induced cellular senescence and transformation. These data show that caveolin-1 is necessary for optimal KSR1-dependent ERK activation by growth factors and oncogenic Ras.

Significance of caveolin-1 regulators in pancreatic cancer

Caveolin-1 is a scaffold protein on the cell membrane. As the main component of caveolae, caveolin-1 is involved in many biological processes that include substance uptake and transmembrane signaling. Many of these processes and thus caveolin-1 contribute to cell transformation, tumorigenesis, and metastasis. Of particular interest are the dual rolesof tumor suppressor and oncogene that caveolin-1 appear to play in different malignancies, including pancreatic cancer. Therefore, analyzing caveolin-1 regulators and understanding their mechanisms of actionis key to identifying novel diagnostic and therapeutic tools for pancreatic cancer. This review details the mechanisms of action of caveolin-1 regulators and the potential significance for pancreatic cancer treatment.

Expression of angiogenic factors is increased in metastasised renal cell carcinomas

Clear cell renal cell carcinomas (ccRCC) have aberrant signalling pathways which affect vascular endothelial growth factor and are related to increased tumour angiogenesis. Little is known about other angiogenesis-associated genes in primary tumours and metastases. Quantitative PCR of 45 angiogenesis-associated gene transcripts was performed on formalin-fixed and paraffin-embedded tissues from primary ccRCC (n = 18) and their metastases (n = 17; in 8/17 cases the corresponding primary tumour could be analysed). In metastases, a significant increase was found in the expression of 15 pro-angiogenic (such as prostaglandin-endoperoxide synthase 1) and also anti-angiogenic (such as TIMP metallopeptidase inhibitor 2) factors. Comparison of a primary with its metastasis performed on eight cases showed that even without preceding anti-angiogenic therapy in metastases expression of angiogenic factors is increased. In ccRCC, the effects of anti-angiogenic factors are superimposed by pro-angiogenic factors. Increased expression of angiogenic factors in metastases might be related to development of resistance after anti-angiogenic therapy but might also be an inherent biological characteristic.

Down-regulation of stromal caveolin-1 expression in esophageal squamous cell carcinoma: a potent predictor of lymph node metastases, early tumor recurrence, and poor prognosis

BACKGROUND

Recent studies have identified loss of stromal caveolin-1 (Cav-1) expression as a new prognostic histological characteristic in various types of human cancers. However, the clinical and pathological significance of stromal Cav-1 expression in esophageal squamous cell carcinoma (ESCC) remains largely unknown. We examined Cav-1 expression in both tumor and stromal cells in ESCC tissue by immunohistochemical analysis to evaluate its clinicopathological significance and prognostic value.

METHODS

A total of 110 patients with ESCC who underwent surgical resection were included in this study. The expression of Cav-1 in both tumor and stromal cells in esophageal tumor tissues was examined immunohistochemically.

RESULTS

Cav-1 expression was found in the cytoplasm of both tumor and stromal cells. Tumor Cav-1 overexpression was observed in 37.3 % tumors, which correlated to deeper tumor invasion (p = 0.038). Down-regulation of stromal Cav-1 expression was observed in 40.9 % tumors. The stromal Cav-1 down-regulation group had more lymph node metastases and more locoregional recurrences than those with higher expression (p = 0.020 and p = 0.002, respectively). In addition, down-regulation of stromal Cav-1 expression was associated with shorter disease-free survival (p < 0.001) and overall survival (p < 0.001). Multivariate analysis revealed that down-regulation of stromal Cav-1 expression was an independent prognostic factor for both disease-free survival (p = 0.028) and overall survival (p = 0.007).

CONCLUSIONS

Down-regulation of stromal Cav-1 expression in ESCC had high malignant potential. It predicts high-risk of lymph node metastases and locoregional recurrence, and it could be a powerful prognostic marker for patients with ESCC.

Gravity-sensitive signaling drives 3-dimensional formation of multicellular thyroid cancer spheroids

This study focused on the effects induced by a random positioning machine (RPM) on FTC-133 thyroid cancer cells and evaluated signaling elements involved in 3-dimensional multicellular tumor spheroid (MCTS) formation. The cells were cultured on the RPM, a device developed to simulate microgravity, and under static 1-g conditions. After 24 h on the RPM, MCTSs swimming in culture supernatants were found, in addition to growth of adherent (AD) cells. Cells grown on the RPM showed higher levels of NF-κB p65 protein and apoptosis than 1-g controls, a result also found earlier in endothelial cells. Employing microarray analysis, we found 487 significantly regulated transcripts belonging not only to the apoptosis pathway but also to other biological processes. Selected transcripts were analyzed with quantitative real-time PCR using the same samples. Compared with 1-g IL-6, IL-8, CD44, and OPN were significantly up-regulated in AD cells but not in MCTSs, while ERK1/2, CAV2, TLN1, and CTGF were significantly down-regulated in AD cells. Simultaneously, the expression of ERK2, IL-6, CAV2, TLN1, and CTGF was reduced in MCTSs. IL-6 protein expression and secretion mirrored its gene expression. Thus, we concluded that the signaling elements IL-6, IL-8, OPN, TLN1, and CTGF are involved with NF-κB p65 in RPM-dependent thyroid carcinoma cell spheroid formation.

Caveolin-1, caveolae, and glioblastoma

Glioblastoma multiforme (GBM) is the most common malignant brain tumor and is characterized by high invasiveness, poor prognosis, and limited therapeutic options. Biochemical and morphological experiments have shown the presence of caveolae in glioblastoma cells. Caveolae are flask-shaped plasma membrane subdomains that play trafficking, mechanosensing, and signaling roles. Caveolin-1 is a membrane protein that participates in the formation of caveolae and binds a multitude of signaling proteins, compartmentalizing them in caveolae and often directly regulating their activity via binding to its scaffolding domain. Caveolin-1 has been proposed to behave either as a tumor suppressor or as an ongogene depending on the tumor type and progress. This review discusses the existing information on the expression and function of caveolin-1 and caveolae in GBM and the role of this organelle and its defining protein on cellular signaling, growth, and invasiveness of GBM. We further analyze the available data suggesting caveolin-1 could be a target in GBM therapy.