title: Effects of the Hedgehog pathway inhibitor GDC-0449 on lung cancer cell lines are mediated by side populations.
abstract: The hedgehog (Hh) signaling pathway has been shown to be activated in the cancer stem cells of several tumor entities. The Hh inhibitor GDC-0449 has been proven to be effective in some cancers but not yet in lung cancer. We aimed at investigating whether GDC-0449 is effective in the lung cancer cell lines HCC (adenocarcinoma) and H1339 (small-cell-lung carcinoma), whether in these cell lines stem cell-like side populations (SPs) can be identified, and whether possible effects of GDC-0449 are mediated via SPs. SPs were identified by spectrum shift and decreased fluorescence after staining with 2.5 μg/ml Hoechst 33342. Expression of proteins was quantified by immunofluorescence. GDC-0449 (25 and 50 μM) inhibited concentration-dependent cell growth in HCC and H1339 cells. Further, the inhibitory effects of cisplatin on cell growth were augmented. In HCC and H1339 cell lines, SPs of 0.57 and 0.46% could be identified, respectively. SP, but not non-SP, cells were able to repopulate the original tumor population. The Hh receptor smoothened was detectable in SP but not in non-SP cells, showing the activation of the Hh pathway only in SPs. GDC-0449 considerably reduced SPs in HCC and H1339 cells. We demonstrate for the first time that GDC-0449 effectively reduces cell growth in lung cancer cell lines. This effect is mediated by the inhibition of stem cell-like SPs.
authors.affiliation: Division of Respiratory Medicine, Medizinische Klinik-Innenstadt, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Fei
authors.initials: F
authors.lastname: Tian
authors.forename: Josef
authors.initials: J
authors.lastname: Mysliwietz
authors.forename: Joachim
authors.initials: J
authors.lastname: Ellwart
authors.forename: Fernando
authors.initials: F
authors.lastname: Gamarra
authors.forename: Rudolf Maria
authors.initials: RM
authors.lastname: Huber
authors.forename: Albrecht
authors.initials: A
authors.lastname: Bergner
mesh_terms: D000813:Anilides / Q000378:metabolism*; D000970:Antineoplastic Agents / Q000494:pharmacology; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology; D001562:Benzimidazoles / Q000378:metabolism; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology; D005434:Flow Cytometry; D005453:Fluorescence; D005455:Fluorescent Antibody Technique; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D053823:Hedgehog Proteins / Q000037:antagonists & inhibitors*; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D011725:Pyridines / Q000378:metabolism*; D015398:Signal Transduction; D055752:Small Cell Lung Carcinoma / Q000378:metabolism / Q000473:pathology; D013997:Time Factors
chemical_list: D000813:Anilides; D000970:Antineoplastic Agents; D001562:Benzimidazoles; D053823:Hedgehog Proteins; C538724:HhAntag691; D011725:Pyridines; C017807:bisbenzimide ethoxide trihydrochloride; D002945:Cisplatin