title: REGγ is a strong candidate for the regulation of cell cycle, proliferation and the invasion by poorly differentiated thyroid carcinoma cells.
abstract: REGγ is a proteasome activator that facilitates the degradation of small peptides. Abnormally high expression of REGγ has been observed in thyroid carcinomas. The purpose of the present study was to explore the role of REGγ in poorly differentiated thyroid carcinoma (PDTC). For this purpose, small interfering RNA (siRNA) was introduced to down-regulate the level of REGγ in the PDTC cell line SW579. Down-regulation of REGγ at the mRNA and protein levels was confirmed by RT-PCR and Western blot analyses. FACS analysis revealed cell cycle arrest at the G1/S transition, the MTT assay showed inhibition of cell proliferation, and the Transwell assay showed restricted cell invasion. Furthermore, the expression of the p21 protein was increased, the expression of proliferating cell nuclear antigen (PCNA) protein decreased, and the expression of the p27 protein was unchanged as shown by Western blot analyses. REGγ plays a critical role in the cell cycle, proliferation and invasion of SW579 cells. The alteration of p21 and PCNA proteins related to the down-regulation of REGγ suggests that p21 and PCNA participate in the process of REGγ regulation of cell cycle progression and cell proliferation. Thus, targeting REGγ has a therapeutic potential in the management of PDTC patients.
authors.affiliation: Department of General Surgery, The First Affiliated Hospital, Chongqing Medical University, China.
authors.forename: M
authors.initials: M
authors.lastname: Zhang
authors.forename: L
authors.initials: L
authors.lastname: Gan
authors.forename: G S
authors.initials: GS
authors.lastname: Ren
mesh_terms: D001324:Autoantigens / Q000235:genetics / Q000502:physiology*; D015153:Blotting, Western; D002453:Cell Cycle / Q000502:physiology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism*; D015536:Down-Regulation; D005434:Flow Cytometry; D006801:Humans; D009361:Neoplasm Invasiveness / Q000473:pathology; D009363:Neoplasm Proteins / Q000235:genetics / Q000502:physiology*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D034741:RNA, Small Interfering / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013964:Thyroid Neoplasms / Q000201:enzymology* / Q000473:pathology
chemical_list: D001324:Autoantigens; D050759:Cyclin-Dependent Kinase Inhibitor p21; C099558:Ki antigen; D009363:Neoplasm Proteins; D018809:Proliferating Cell Nuclear Antigen; D034741:RNA, Small Interfering; D046988:Proteasome Endopeptidase Complex