title: Attenuation of cancer-initiating cells stemness properties by abrogating S100A4 calcium binding ability in head and neck cancers.
abstract: S100A4 is a calcium-binding protein capable of promoting epithelial-mesenchymal transition. Previously, we have demonstrated that S100A4 is required to sustain the head and neck cancer-initiating cells (HN-CICs) subpopulation. In this study, to further investigate the molecular mechanism, we established the head and neck squamous cell carcinoma (HNSCC) cell lines stably expressing mutant S100A4 proteins with defective calcium-binding sites on either N-terminal (NM) or C-terminal (CM), or a deletion of the last 15 amino-acid residues (CD). We showed that the NM, CM and CD harboring sphere cells that were enriched with HN-CICs population exhibited impaired stemness and malignant properties in vitro, as well as reduced tumor growth ability in vivo. Mechanistically, we demonstrated that mutant S100A4 proteins decreased the promoter activity of Nanog, likely through inhibition of p53. Moreover, the biophysical analyses of purified recombinant mutant S100A4 proteins suggest that both NM and CM mutant S100A4 were very similar to the WT S100A4 with subtle difference on the secondary structure, and that the CD mutant protein displayed the unexpected monomeric form in the solution phase.Taken together, our results suggest that both the calcium-binding ability and the C-terminal region of S100A4 are important for HN-CICs to sustain its stemness property and malignancy, and that the mechanism could be mediated by repressing p53 and subsequently activating the Nanog expression.
authors: Institute of Oral Biology, National Yang-Ming University, Taipei, Taiwan.
authors: Li-Hao
authors: LH
authors: Cheng
authors: Department of Dentistry, School of Dentistry, National Yang-Ming University, Taipei, Taiwan.
authors: Kai-Feng
authors: KF
authors: Hung
authors: School of Medicine, National Yang-Ming University, Taipei, Taiwan.|Department of Orthopedics and Traumatology, Taipei Veterans General Hospital, Taipei, Taiwan.
authors: Tung-Fu
authors: TF
authors: Huang
authors: Department of Microbiology and Immunology, Medical College, National Cheng Kung University, Tainan, Taiwan.
authors: Hsin-Pei
authors: HP
authors: Hsieh
authors: Department of Microbiology and Immunology, Medical College, National Cheng Kung University, Tainan, Taiwan.
authors: Shu-Ying
authors: SY
authors: Wang
authors: Graduate Institute of Chinese Medical Science and Institute of Medical Science, China Medical University, Taichung, Taiwan.|Institute of Basic Medical Science, China Medical University, Taichung, Taiwan.|Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan.
authors: Chih-Yang
authors: CY
authors: Huang
authors: Institute of Oral Biology, National Yang-Ming University, Taipei, Taiwan.|Department of Dentistry, School of Dentistry, National Yang-Ming University, Taipei, Taiwan.|Graduate Institute of Chinese Medical Science and Institute of Medical Science, China Medical University, Taichung, Taiwan.|Department of Dentistry, Taipei Veterans General Hospital, Taipei, Taiwan.|Genome Research Center, National Yang-Ming University, Taipei, Taiwan.|National Yang-Ming University VGH Genome Research Center, Taipei, Taiwan.
authors: Jeng-Fan
authors: JF
authors: Lo
mesh_terms: D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D000091342:Endoplasmic Reticulum Chaperone BiP; D015972:Gene Expression Regulation, Neoplastic; D006258:Head and Neck Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009154:Mutation; D000071317:Nanog Homeobox Protein / Q000235:genetics / Q000378:metabolism; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology; D010641:Phenotype; D011401:Promoter Regions, Genetic; D000072417:Protein Domains; D017433:Protein Structure, Secondary; D000071999:S100 Calcium-Binding Protein A4 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D000077195:Squamous Cell Carcinoma of Head and Neck; D013329:Structure-Activity Relationship; D013997:Time Factors; D014162:Transfection; D047368:Tumor Burden; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
chemical_list: D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; C000717248:Hspa5 protein, mouse; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; D000071999:S100 Calcium-Binding Protein A4; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C077591:S100A4 protein, human; D002118:Calcium
keywords: GRP78; Nanog; epithelial-mesenchymal transition; head and neck squamous cell carcinomas; p53