gant-61 and Kidney-Neoplasms

Renal cell carcinoma (RCC) is the most lethal urologic malignancy; however, the molecular events supporting RCC carcinogenesis and progression remain poorly understood. In this study, based on the analysis of gene expression profile data from human clear cell RCC (ccRCC) and the corresponding normal tissues, we discovered that Hedgehog (HH) pathway component genes GLI1 and GLI2 were significantly elevated in ccRCC. Survival analysis of a large cohort of ccRCC samples demonstrated that the expression of GLI1 and GLI2 was negatively correlated with patient overall survival. Clinical sample-based VHL mutation and cell model-based VHL manipulation studies all indicated that the activation of GLI1 and GLI2 was not affected by VHL status. Further signaling pathway dissections demonstrated that GLI1 and GLI2 were activated by the phosphoinositide 3-kinase (PI3K)/AKT pathway, but not mediated by the canonical HH/SMO/GLI signaling. Up-regulation of GLI1 and GLI2 promoted RCC proliferation and clonogenic ability, whereas, a combination of GLIs inhibitor Gant61 and AKT inhibitor Perifosine synergistically suppressed RCC growth and induced apoptosis in vitro and in vivo. Therefore, this study identifies that GLI1 and GLI2 are critical for RCC carcinogenesis, and also provides an alternative therapeutic strategy for RCC.

Topics: Carcinoma, Renal Cell; Cells, Cultured; Humans; Kidney Neoplasms; Kruppel-Like Transcription Factors; Nuclear Proteins; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Pyridines; Pyrimidines; Receptors, G-Protein-Coupled; Signal Transduction; Smoothened Receptor; Transcription Factors; Zinc Finger Protein GLI1; Zinc Finger Protein Gli2

Renal cell carcinoma (RCC) is often considered a radioresistant tumor, but the molecular mechanism underlying its radioresistance is poorly understood. This study explored the roles of hypoxia-inducible factor 2α (HIF2α) and sonic hedgehog (SHH)-GLI1 signaling in mediating the radioresistance of RCC cells and to unveil the interaction between these 2 signaling pathways.. The activities of SHH-GLI1 signaling pathway under normoxia and hypoxia in RCC cells were examined by real-time polymerase chain reaction, Western blot, and luciferase reporter assay. The expression of HIF2α and GLI1 in RCC patients was examined by immunohistochemistry, and their correlation was analyzed. Furthermore, RCC cells were treated with HIF2α-specific shRNA (sh-HIF2α), GLI1 inhibitor GANT61, or a combination to determine the effect of ionizing radiation (IR) on RCC cells based on clonogenic assay and double-strand break repair assay.. RCC cells exhibited elevated SHH-GLI1 activities under hypoxia, which was mediated by HIF2α. Hypoxia induced GLI1 activation through SMO-independent pathways that could be ablated by PI3K inhibitor or MEK inhibitor. Remarkably, the SHH-GLI1 pathway also upregulated HIF2α expression in normoxia. Apparently, there was a positive correlation between HIF2α and GLI1 expression in RCC patients. The combination of sh-HIF2α and GLI1 inhibitor significantly sensitized RCC cells to IR.. Cross-talk between the HIF2α and SHH-GLI1 pathways was demonstrated in RCC. Cotargeting these 2 pathways, significantly sensitizing RCC cells to IR, provides a novel strategy for RCC treatment.

Topics: Basic Helix-Loop-Helix Transcription Factors; Carcinoma, Renal Cell; Cell Hypoxia; Fluorescent Antibody Technique; Humans; Kidney Neoplasms; Luciferases, Renilla; Neoplasm Proteins; Pyridines; Pyrimidines; Radiation Tolerance; Real-Time Polymerase Chain Reaction; Transcription Factors; Tumor Stem Cell Assay; Up-Regulation; Von Hippel-Lindau Tumor Suppressor Protein; Zinc Finger Protein GLI1