Affiliations: [a] Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand | [b] Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand | [c] HRH Princess Chulabhorn College of Medical Science, Bangkok 10210, Thailand | [d] Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand | [e] Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand | [f] Liver Fluke and Cholangiocarcinoma Research Center, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
Correspondence:
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Corresponding author: Poom Adisakwattana, Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand. Tel./Fax: +66 2 643 5600; E-mail: [email protected].
Abstract: BACKGROUND:Alterations and mutations of endo-lysosomal trafficking proteins have been associated with cancer progression. Identification and characterization of endo-lysosomal trafficking proteins in invasive cholangiocarcinoma (CCA) cells may benefit prognosis and drug design for CCA. OBJECTIVE: To identify and characterize endo-lysosomal trafficking proteins in invasive CCA. METHODS: A lysosomal-enriched fraction was isolated from a TNF-α induced invasive CCA cell line (KKU-100) and uninduced control cells and protein identification was performed with nano-LC MS/MS. Novel lysosomal proteins that were upregulated in invasive CCA cells were validated by real-time RT-PCR. We selected Rab7 for further studies of protein level using western blotting and subcellular localization using immunofluorescence. The role of Rab7 in CCA invasion was determined by siRNA gene knockdown and matrigel transwell assay. RESULTS:Rab7 mRNA and protein were upregulated in invasive CCA cells compared with non-treated controls. Immunofluorescence studies demonstrated that Rab7 was expressed predominantly in invasive CCA cells and was localized in the cytoplasm and lysosomes. Suppression of Rab7 translation significantly inhibited TNF-α-induced cell invasion compared to non-treated control (p= 0.044). CONCLUSIONS: Overexpression of Rab7 in CCA cells was associated with cell invasion, supporting Rab7 as a novel candidate for the development of diagnostic and therapeutic strategies for CCA.
