| Malignant lymphoma (ML) is derived from the human immune system cells and their progenitor cells and malignant disease. According to clinical and pathological features, ML can be divided into two types:Hodgkin’s lymphoma (HL) and non-HodgKin lymphoma (NHL). The incidence of ML is increasing year by year in China. NHL is the growing fastest tumor, its incidence in the world’s the fifth in female and the sixth in male. It is seriously threatening human’s health and life.In China, From January2000to December2008, a total number of6,382patients with lymphoma were established, of which mature B-cell neoplasms accounted for56%, mature T-and NK-cell neoplasms occupied26%, and precursor lymphoid neoplasms and Hodgkin lymphomas were5%and13%, respectively. The top six subtypes of non-Hodgkin lymphoma:NK/T cell ymphoma is only second to diffuse large B-cell lymphoma.Compared with other areas in the world, NK/T cell lymphoma is high frequency in Asia in especial China. Owing to onset occult, difficult for early diagnosis, high invasion, rapid progression, short surviveal and poor prognosis features, the disease threats to human health seriously. Concurrent chemoradiation is the way to treat the early state, and comprehensive treatment including chemotherapy is effective treatments for middle and late state. At present, there is no standard treatment regimen for NK/T cell lymphoma, it is necessary to find the preferred chemotherapy drugs. Gemcitabine has been demonstrated single agent efficacy in non-HodgKin lymphomas. In our study, gemcitabine was highly sensitive to NK/T-cell lymphoma cell lines YTS and SNK-6, gemcitabine may become effective drug to cure NK/T-cell lymphoma. But multidrug resistance is the main restriction factor for chemotherapeutic effect, primary and secondary drug resistance is a common and formidable obstacle to therapy in mature NK/T-cell lymphomas. A Gemcitabine-resistant cell line of human NK/T-cell lymphoma was established and named YTS-Gem. YTS-Gem was a ideal model to detect the resistance mechanisms of NK/T-cell lymphomas and provide vital clues of basic and clinical research for NK/T-cell lymphomas.ObjectiveTo develop a Gemcitabine-resistant cell line of human NK/T-cell lymphoma, after that we investigate its biological characteristics, detect the differential genes expression between the two cell lines and study the drug-resistant mechanism of NK/T-cell lymphoma.MethodsYTS was exposured to increased Gemcitabine concentration progressively to obtain stable Gemcitabine-resistant YTS-Gem in vitro. The morphological features and growth characters of YTS-Gem were observed by inverted biological microscope. MTT assay was used to observe its sensitivity of drug resistance. The growth curve was observed and the doubling time was calculated. Flow cytometry assay was used to evaluate the cell cycle distribution in two cell lines. Fluorescence real-time quantitative polymerase chain reaction (Real-time PCR)was used to test the differenrial expressions of genes related to cell cycle Caspase, apoptosis genes p53, TRAIL, and Mcl-1, repairing and restructuring related genes RRM1and RRM2, cellular metabolism related genes dCk and dCDA, drug-resistant related to genes mdr-1, LRP and MRP.Results1A Gemcitabine-resistant human NK/T-cell lymphoma cell line was established successfully.2Compared with the YTS cell, YTS-Gem showed great changes in biological characteristics. The IC50of YTS-Gem and YTS were1.960μg/mL,0.049μg/mL,and the drug resistance indexes of cell line YTS-Gem to gemcitabine was40. Compared with the YTS cell, YTS-Gem exhibited a lower growth rate, and their population doubling time were41.36h and51.17h, meanwhile cell distribution increased in S phase and decreased in G0/G1phase (P<0.01), but no difference in G2/M.3The expressions of Mcl-1, P53, MRP, dCDA, RRM1and RRM2were increasing significantly in YTS-Gem (P<0.05), but the expressions of dCK, Caspase and TRAIL were decreasing significantly in YTS-Gem (P<0.05), and the experessions of mdr-1and LRP were similar with no significant difference (P>0.05).Conclusion1A Gemcitabine-resistant human NK/T-cell lymphoma cell line was successfully established named YTS-Gem. Compared with the YTS cell, YTS-Gem showed significant differences in biological characteristics.2The expressions of comprehensive genes were discrepant between two cell lines, including genes associated with cell cycle, apoptosis, repairing and restructuring, cellular metabolism and drug-resistant. |
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