ABSTRACT
Clear cell renal cell carcinoma (ccRCC) is an aggressive disease with unpredictable behaviour. Clinical parameters are not always accurate for prognosis prediction. The integration of molecular markers to prognostic models can significantly improve prognostic assessment and consequently patient management. We assessed the expression of alpha-enolase (ENO1) protein by immunohistochemistry in 360 patients with primary ccRCC and correlated its expression with multiple clinicopathological parameters including stage, grade, tumor size, disease-free and overall survival. Cox proportional hazard regression models adjusted for clinicopathological factors were used to test for a link between ENO1 expression and both disease-free and overall survival. We correlated ENO1 mRNA expression with overall survival in an independent set of 428 ccRCC cases from The Cancer Genome Atlas. ENO1 showed cytoplasmic, membranous and nuclear staining patterns. There is a statistically significant negative correlation between ENO1 expression, tumor stage, and grade. ENO1 expression also shows a statistically significant direct correlation with disease-free survival (p = 0.011) and overall survival (p = 0.030) in ccRCC. Patients with higher ENO1 expression had lower hazard ratio of recurrence, although this was not statistically significant (HR = 0.330, p = 0.060). These findings were validated at the mRNA level in an independent set of 428 ccRCC cases which also showed that low ENO1 expression is associated with significantly shorter overall survival. Down-regulation of ENO1 can be a predictor of poor prognosis in ccRCC, and it can be a potential prognostic marker.
Subject(s)
Biomarkers, Tumor/metabolism , Carcinoma, Renal Cell/pathology , DNA-Binding Proteins/metabolism , Kidney Neoplasms/pathology , Neoplasm Recurrence, Local/pathology , Phosphopyruvate Hydratase/metabolism , Tumor Suppressor Proteins/metabolism , Biomarkers, Tumor/genetics , Carcinoma, Renal Cell/genetics , Carcinoma, Renal Cell/metabolism , Carcinoma, Renal Cell/mortality , Cohort Studies , DNA-Binding Proteins/genetics , Follow-Up Studies , Humans , Immunoenzyme Techniques , Kidney Neoplasms/genetics , Kidney Neoplasms/metabolism , Kidney Neoplasms/mortality , MicroRNAs/genetics , Neoplasm Grading , Neoplasm Invasiveness , Neoplasm Recurrence, Local/genetics , Neoplasm Recurrence, Local/metabolism , Neoplasm Recurrence, Local/mortality , Neoplasm Staging , Phosphopyruvate Hydratase/genetics , Prognosis , RNA, Messenger/genetics , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Survival Rate , Tumor Cells, Cultured , Tumor Suppressor Proteins/geneticsABSTRACT
Renal cell carcinoma (RCC) is an aggressive disease, with 35% chance of metastasis. The 'cancer stem cell' hypothesis suggests that a subset of cancer cells possess stem cell properties and is crucial in tumor initiation, metastasis and treatment resistance. We isolated RCC spheres and showed that they exhibit cancer stem cell/ tumor initiating cell-like properties including the formation of self-renewing spheres, high tumorigenicity and the ability to differentiate to cell types of the original tumor. Spheres showed increased expression of stem cell-related transcription factors and mesenchymal markers. miRNAs were differentially expressed between RCC spheres and their parental cells. Inhibition of miR-17 accelerated the formation of RCC spheres which shared molecular characteristics with the spontaneous RCC spheres. Target prediction pointed out TGFß pathway activation as a possible mechanism to drive RCC sphere formation. We demonstrate that miR-17 overexpression interferes with the TGFß-EMT axis and hinders RCC sphere formation; and validated TGFBR2 as a direct and biologically relevant target during this process. Thus, a single miRNA may have an impact on the formation of highly tumorigenic cancer spheres of kidney cancer.
Subject(s)
Carcinoma, Renal Cell/genetics , Carcinoma, Renal Cell/pathology , Kidney Neoplasms/genetics , Kidney Neoplasms/pathology , MicroRNAs/antagonists & inhibitors , Animals , Carcinoma, Renal Cell/metabolism , Cell Growth Processes/physiology , Cell Line, Tumor , Epithelial-Mesenchymal Transition , Humans , Kidney Neoplasms/metabolism , Male , Mice , Mice, Inbred NOD , MicroRNAs/genetics , Neoplastic Stem Cells/metabolism , Neoplastic Stem Cells/pathology , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Receptor, Transforming Growth Factor-beta Type II , Receptors, Transforming Growth Factor beta/genetics , Receptors, Transforming Growth Factor beta/metabolism , Signal Transduction , Spheroids, Cellular/pathology , Transfection , Transforming Growth Factor beta/metabolism , Xenograft Model Antitumor AssaysABSTRACT
BACKGROUND: Over 90% of cancer-related deaths in clear cell renal cell carcinoma (RCC) are caused by tumor relapse and metastasis. Thus, there is an urgent need for new molecular markers that can potentiate the efficacy of the current clinical-based models of prognosis assessment. The objective of this study is to evaluate the potential significance of lactate dehydrogenase A (LDHA), assessed by immunohistochemical staining, as a prognostic marker in clear cell renal cell carcinoma in relation to clinicopathological features and clinical outcome. METHODS: We assessed the expression of LDHA at the protein level, by immunohistochemistry, and correlated its expression with multiple clinicopathological features including tumor size, clinical stage, histological grade, disease-free and overall survival in 385 patients with primary clear cell renal cell carcinoma. We also correlated the LDHA expression with overall survival, at mRNA level, in an independent data set of 170 clear cell renal cell carcinoma cases from The Cancer Genome Atlas databases. Cox proportional hazards models adjusted for the potential clinicopathological factors were used to test for associations between the LDHA expression and both disease-free survival and overall survival. RESULTS: There is statistically significant positive correlation between LDHA level of expression and tumor size, clinical stage and histological grade. Moreover, LDHA expression shows significantly inverse correlation with both disease-free survival and overall survival in patients with clear cell renal cell carcinoma. Our results are validated by examining LDHA expression, at the mRNA level, in the independent data set of clear cell renal cell carcinoma cases from The Cancer Genome Atlas databases which also shows that higher lactate dehydrogenase A expression is associated with significantly shorter overall survival. CONCLUSION: Our results indicate that LDHA up-regulation can be a predictor of poor prognosis in clear cell renal cell carcinoma. Thus, it represents a potential prognostic biomarker that can boost the accuracy of other prognostic models in patients with clear cell renal cell carcinoma.
