Wnt inhibitory factor 1 suppresses cancer stemness and induces cellular senescence.
Hyperactivation of the Wingless-type (Wnt)/β-catenin pathway promotes tumor initiation, tumor growth and metastasis in various tissues. Although there is evidence for the involvement of Wnt/β-catenin pathway activation in salivary gland tumors, the precise mechanisms are unknown. Here we report for the first time that downregulation of the Wnt inhibitory factor 1 (WIF1) is a widespread event in salivary gland carcinoma ex-pleomorphic adenoma (CaExPA). We also show that WIF1 downregulation occurs in the CaExPA precursor lesion pleomorphic adenoma (PA) and indicates a higher risk of progression from benign to malignant tumor. Our results demonstrate that diverse mechanisms including WIF1 promoter hypermethylation and loss of heterozygosity contribute to WIF1 downregulation in human salivary gland tumors. In accordance with a crucial role in suppressing salivary gland tumor progression, WIF1 re-expression in salivary gland tumor cells inhibited cell proliferation, induced more differentiated phenotype and promoted cellular senescence, possibly through upregulation of tumor-suppressor genes, such as p53 and p21. Most importantly, WIF1 significantly diminished the number of salivary gland cancer stem cells and the anchorage-independent cell growth. Consistent with this observation, WIF1 caused a reduction in the expression of pluripotency and stemness markers (OCT4 and c-MYC), as well as adult stem cell self-renewal and multi-lineage differentiation markers, such as WNT3A, TCF4, c-KIT and MYB. Furthermore, WIF1 significantly increased the expression of microRNAs pri-let-7a and pri-miR-200c, negative regulators of stemness and cancer progression. In addition, we show that WIF1 functions as a positive regulator of miR-200c, leading to downregulation of BMI1, ZEB1 and ZEB2, with a consequent increase in downstream targets such as E-cadherin. Our study emphasizes the prognostic and therapeutic potential of WIF1 in human salivary gland CaExPA. Moreover, our findings demonstrate a novel mechanism by which WIF1 regulates cancer stemness and senescence, which might have major implications in the field of cancer biology.
Department of Otorhinolaryngology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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Ramachandran
Department of Otorhinolaryngology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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Ganapathy
Department of Pathology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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Gillies
Serviço de Anatomia Patológica, Instituto Português de Oncologia de Francisco Gentil and Instituto de Anatomia Patológica, Faculdade de Medicina de Lisboa, Lisbon, Portugal.
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Fonseca
1] US Department of Veterans Affairs Medical Center, Oklahoma City, OK, USA [2] Peggy and Charles Stephenson Oklahoma Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA [3] Department of Medicine, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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Sureban
1] US Department of Veterans Affairs Medical Center, Oklahoma City, OK, USA [2] Peggy and Charles Stephenson Oklahoma Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA [3] Department of Medicine, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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Houchen
Department of Dermatology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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Reis
1] Department of Otorhinolaryngology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA [2] US Department of Veterans Affairs Medical Center, Oklahoma City, OK, USA [3] Peggy and Charles Stephenson Oklahoma Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA [4] Department of Cell Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA [5] Department of Pediatrics, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA [6] The Oklahoma Tobacco Research Center, Oklahoma City, OK, USA.
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Queimado
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D008949:Adenoma, Pleomorphic / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D059447:Cell Cycle Checkpoints; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D016922:Cellular Senescence; D019175:DNA Methylation; D018450:Disease Progression; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D019656:Loss of Heterozygosity; D035683:MicroRNAs / Q000378:metabolism; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012468:Salivary Gland Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D013997:Time Factors; D014162:Transfection; D060449:Wnt Signaling Pathway
D048868:Adaptor Proteins, Signal Transducing; D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D035683:MicroRNAs; D012097:Repressor Proteins; C485569:WIF1 protein, human