title: Aberrant hedgehog signaling is responsible for the highly invasive behavior of a subpopulation of hepatoma cells.
abstract: Hepatoma exhibits a series of heterogeneous subpopulations in its cell surface markers, tumorigenicity, invasion and metastatic capability. We previously demonstrated that the CD133(-)/EpCAM(-) hepatoma subpopulation was more metastatic than its counterpart; however, the controlling mechanisms are unexplored. The present study aimed to delineate the significance of aberrant hedgehog (Hh) signaling in the mediation of metastases. Fluorescence-activated cell sorting-enriched CD133(-)/EpCAM(-) (double negative, DN), Huh-7 cells underwent a transwell selection for metastatic cells (transwell-selected, TS). The TS cells displayed much greater metastatic activity as evidenced by an increased invasion rate, extremely upregulated expression of matrix metalloproteinase (MMP)-1/2/9 genes compared with DN and double-positive (DP) subpopulations. In contrast to DP cells, TS cells lost E-cadherin and were all vimentin-positive as shown by immunocytochemistry. There was a transitional increase in Gli-1/2 gene expression levels from DP, DN to TS subpopulations, which was consistent with elevated Gli-1/2 or Twist-1 protein levels in the nuclear fraction. Furthermore, truncated Gli-1 (tGli-1), which transactivates molecules involved in metastasis, was detected in the highly invasive Huh-7 cell subpopulation, but not in less metastatic hepatoma cells or normal hepatocytes. The enhanced metastatic features with increased expression of MMPs as well as the presence of twist and snail genes in TS Huh-7 cells were reversed by LDE225, a potent Smoothened antagonist. In conclusion, the highly metastatic capability of a unique TS subpopulation was highly attributed to significant epithelial-mesenchymal transition, enhanced Hh activity and aberrant occurrence of a tGli-1 variant, which appears to be responsible for the highly invasive behavior.
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology & Hepatology, University of California, Davis Medical Center, Sacramento, CA, USA.|Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Y-H
authors.initials: YH
authors.lastname: Fan
authors.affiliation: Key Laboratory of Molecular Virology, Fudan University Shanghai Medical College, Shanghai, China.|Department of Gastroenterology, Shanghai Jing'an District Central Hospital, Shanghai, China.
authors.forename: J
authors.initials: J
authors.lastname: Ding
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology & Hepatology, University of California, Davis Medical Center, Sacramento, CA, USA.
authors.forename: S
authors.initials: S
authors.lastname: Nguyen
authors.affiliation: Key Laboratory of Molecular Virology, Fudan University Shanghai Medical College, Shanghai, China.
authors.forename: X-J
authors.initials: XJ
authors.lastname: Liu
authors.affiliation: Key Laboratory of Molecular Virology, Fudan University Shanghai Medical College, Shanghai, China.
authors.forename: G
authors.initials: G
authors.lastname: Xu
authors.affiliation: Key Laboratory of Molecular Virology, Fudan University Shanghai Medical College, Shanghai, China.
authors.forename: H-Y
authors.initials: HY
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Molecular Virology, Fudan University Shanghai Medical College, Shanghai, China.
authors.forename: N-N
authors.initials: NN
authors.lastname: Duan
authors.affiliation: Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
authors.forename: S-M
authors.initials: SM
authors.lastname: Yang
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology & Hepatology, University of California, Davis Medical Center, Sacramento, CA, USA.|Institute for Regenerative Cures, University of California, Davis Medical Center, Sacramento, CA, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Zern
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology & Hepatology, University of California, Davis Medical Center, Sacramento, CA, USA.|Key Laboratory of Molecular Virology, Fudan University Shanghai Medical College, Shanghai, China.|Institute for Regenerative Cures, University of California, Davis Medical Center, Sacramento, CA, USA.|Shanghai Institute of Liver Diseases, Fudan University Affiliated Zhongshan Hospital, Shanghai, China.|University of California, Davis Comprehensive Cancer Center, Sacramento, CA, USA.
authors.forename: J
authors.identifier: http://orcid.org/0000-0001-9933-7364
authors.initials: J
authors.lastname: Wu
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D058750:Epithelial-Mesenchymal Transition; D053823:Hedgehog Proteins / Q000378:metabolism*; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008666:Metalloendopeptidases / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D000071676:Zinc Finger Protein GLI1
chemical_list: C400551:GLI1 protein, human; D053823:Hedgehog Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; D000071676:Zinc Finger Protein GLI1; D008666:Metalloendopeptidases