gant-61 and Carcinogenesis

Glioblastoma (GBM) is the most common adult primary tumor of the CNS characterized by rapid growth and diffuse invasiveness into the brain parenchyma. The GBM resistance to chemotherapeutic drugs may be due to the presence of cancer stem cells (CSCs). The CSCs activate the same molecular pathways as healthy stem cells such as WNT, Sonic hedgehog (SHH), and Notch. Mutations or deregulations of those pathways play a key role in the proliferation and differentiation of their surrounding environment, leading to tumorigenesis. Here we investigated the effect of SHH signaling pathway inhibition in human GBM cells by using GANT-61, considering stem cell phenotype, cell proliferation, and cell death. Our results demonstrated that GANT-61 induces apoptosis and autophagy in GBM cells, by increasing the expression of LC3 II and cleaved caspase 3 and 9. Moreover, we observed that SHH signaling plays a crucial role in CSC phenotype maintenance, being also involved in the epithelial-mesenchymal transition (EMT) phenotype. We also noted that SHH pathway modulation can regulate cell proliferation as revealed through the analysis of Ki-67 and c-MYC expressions. We concluded that SHH signaling pathway inhibition may be a promising therapeutic approach to treat patients suffering from GBM refractory to traditional treatments.

Topics: Apoptosis; Autophagy; Brain Neoplasms; Carcinogenesis; Cell Line, Tumor; Cell Proliferation; Epithelial-Mesenchymal Transition; Glioblastoma; Hedgehog Proteins; Humans; Neoplastic Stem Cells; Pyridines; Pyrimidines

Topics: Animals; Antineoplastic Agents, Alkylating; Autophagy; Beclin-1; Carcinogenesis; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cell Survival; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Glioblastoma; Hedgehog Proteins; Humans; Mice; Oxidative Stress; Pyridines; Pyrimidines; Signal Transduction; Temozolomide; Xenograft Model Antitumor Assays; Zinc Finger Protein GLI1

Multidrug resistance is one of the reasons for low survival of advanced hepatocellular carcinoma (HCC). Our previous studies indicate that the hedgehog signalling is involved in hepatic carcinogenesis, metastasis and chemo-resistance. The present study aims to uncover molecular mechanisms underlying hepatoma chemo-resistance. TAP1 and GLI1/2 gene expression was assessed in both poorly differentiated hepatoma cells and HCC specimens. Potential GLI-binding site in the TAP1 promoter sequence was validated by molecular assays. Approximately 75% HCC specimens exhibited an elevated expression of hedgehog GLI1 transcription factor compared with adjacent liver tissue. Both GLI1/2 and TAP1 protein levels were significantly elevated in poorly differentiated hepatoma cells. Both Huh-7-trans and Huh-7-DN displayed more karyotypic abnormalities and differential gene expression profiles than their native Huh-7 cells. Sensitivity to Sorafenib, doxorubicin and cisplatin was remarkably improved after either GLI1 or TAP1 gene was inhibited by an RNAi approach or by a specific GLI1/2 inhibitor, GANT61. Further experiments confirmed that hedgehog transcription factor GLI1/2 binds to the TAP1 promoter, indicating that TAP1 is one of GLI1/2 target genes. In conclusion, TAP1 is under direct transcriptional control of the hedgehog signalling. Targeting hedgehog signalling confers a novel insight into alleviating drug resistance in the treatment of refractory HCC.

Topics: ATP Binding Cassette Transporter, Subfamily B, Member 2; Carcinogenesis; Carcinoma, Hepatocellular; Cell Line, Tumor; DNA-Binding Proteins; Drug Resistance, Neoplasm; Female; Gene Expression Regulation, Neoplastic; Hedgehog Proteins; Humans; Liver Neoplasms; Male; Nuclear Proteins; Promoter Regions, Genetic; Pyridines; Pyrimidines; Signal Transduction; Zinc Finger Protein GLI1; Zinc Finger Protein Gli2