Sonic Hedgehog inhibition as a strategy to augment radiosensitivity of hepatocellular carcinoma
Journal
Journal of Gastroenterology and Hepatology (Australia)
Journal Volume
30
Journal Issue
8
Pages
1317-1324
Date Issued
2015
Author(s)
Abstract
Background and Aim: Sonic Hedgehog (SHH) is a regulator in tumorigenesis of hepatocellular carcinoma (HCC). This study aimed to determine whether radiation-induced SHH signaling occurs in HCC and whether SHH inhibitor acts as a radiosensitizer. Methods: The in vitro effects of combining SHH ligand (recombinant human SHH) or inhibitor (cyclopamine) with irradiation were evaluated in the human HCC cell lines, Huh-7 and PLC/PRF/5, and murine cell line BNL. Cell survival and apoptosis were measured using a colony formation assay, annexin-V staining, and poly (ADP-ribose) polymerase activation. Western blotting and immunofluorescence staining were used to detect protein expression. The in vivo response to radiotherapy and/or cyclopamine was tested in BALB/c mice bearing an orthotopic allogeneic tumor. Results: Treatment of HCC cells with irradiation and SHH ligand had a protective effect on clonogenic cell survival. Treatment with irradiation and cyclopamine was a more potent inhibitor of cell proliferation than either modality alone. The antiproliferative activity of cyclopamine was attributable to apoptosis induction. Radiation dose-dependently upregulated the expression of Gli-1 (a transcription factor induced by SHH), and this effect was observed mainly in the nucleus. When combined with cyclopamine, irradiation inhibited Gli-1 and increased DNA double-strand breakage. Radiotherapy increased SHH and Gli-1 expression in allogeneic tumor. When compared with radiotherapy alone, cyclopamine with radiotherapy reduced the mean tumor size of orthotopic tumors by 67% (P<0.05). Conclusion: Combining an SHH inhibitor with radiotherapy may enhance HCC cell and orthotopic tumor radiosensitivity. ? 2015 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.
SDGs
Other Subjects
cyclopamine; double stranded DNA; lipocortin 5; nicotinamide adenine dinucleotide adenosine diphosphate ribosyltransferase; recombinant protein; recombinant sonic hedgehog protein; sonic hedgehog protein; transcription factor Gli1; unclassified drug; cyclopamine; GLI1 protein, human; ligand; radiosensitizing agent; recombinant protein; SHH protein, human; sonic hedgehog protein; transcription factor; Veratrum alkaloid; animal model; antiproliferative activity; apoptosis; Article; cancer chemotherapy; cancer radiotherapy; carcinoma cell line; cell nucleus; cell proliferation; cell protection; cell survival; colony formation; controlled study; double stranded DNA break; drug efficacy; enzyme activity; human; human cell; human cell culture; immunofluorescence test; immunohistochemistry; in vitro study; in vivo study; irradiation; liver cell carcinoma; male; mouse; nonhuman; priority journal; protein expression; radiation dose; radiosensitivity; receptor upregulation; treatment response; tumor volume; tumor xenograft; Western blotting; animal; antagonists and inhibitors; Bagg albino mouse; cancer transplantation; carcinogenesis; Carcinoma, Hepatocellular; disease model; drug effects; gene expression; genetics; Liver Neoplasms; molecularly targeted therapy; multimodality cancer therapy; pathology; pathophysiology; physiology; radiation response; radiation tolerance; signal transduction; tumor cell line; Animals; Apoptosis; Carcinogenesis; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Cell Survival; Combined Modality Therapy; Disease Models, Animal; DNA Breaks, Double-Stranded; Dose-Response Relationship, Radiation; Gene Expression; Hedgehog Proteins; Humans; Ligands; Liver Neoplasms; Mice; Mice, Inbred BALB C; Molecular Targeted Therapy; Neoplasm Transplantation; Radiation Tolerance; Radiation-Sensitizing Agents; Recombinant Proteins; Signal Transduction; Transcription Factors; Veratrum Alkaloids
Publisher
Blackwell Publishing
Type
journal article