| Lymphoma refers to a malignancy of the lymph system. The disease is divided into B cell lymphoma and T cell lymphoma(TCL) according to cell origin. Recently, targeting therapeutic agent, such as tyrosine kinase inhibitor and Rituximab, have been widely used into clinical with the advancement of the study of molecular biology, which significantly improve the prognosis of lymphoma/leukemia derived from B cells. However, there are less molecular biology therapeutic regiments targeting to T cell lymphoma compared to B cell lymphoma, as the pathogenesis, biologic behavior and metabolic characteristics of the disease remain unclear and studies focusing on this field are insufficient. Additionally, a large number of patients suffering T cell lymphoma have resistance to conventional chemotherapy regimens, such as CHOP and ESHAP, leading to poor prognosis. Thus, it is necessary to investigate biochemical metabolism characteristics and mechanisms of malignant T cells, that may provide novel therapies for the aggressive disease.Leptin is the product of obese (ob) gene and mainly secreted by adipocyte. Mature leptin is a secreted protein composed of 146 amino acids.The structure of leptin has significant similarity to the structures of granulocyte colony-stimulating factor (G-CSF) and to the interleukin (IL)-6 family of cytokines. Leptin receptor(ObR) belongs to the class I cytokine receptor superfamily, is a single membrane-spanning receptor. When leptin bind leptin receptor, several signaling pathways are activated, including JAK/STAT, MAPK/ERK1/2 and PI3K signaling pathway, participating in feeding, energy consumption, cell proliferation and apoptosis. In diffuse large B cell lymophoma (DLBCL), higher level of ObR expression were observed than in Reactive lymphoid hyperplasia (RLH). And leptin promote cell growth and inhibit cell apoptosis in DLBCL cells via PI3K/AKT signaling pathway.Glucose is the major energy resource to maintain cell proliferation and homeostasis. In malignancy, glucose metabolism plays a even more important role than in nomal tissue, because of the faster cell growth and larger demand of calories of malignant cells. Glucose metabolism not only involves in proliferation and apoptosis of tumor cells, but also affects tumor prognosis. Glucose transporters (Gluts) is the main carrier protein of transporting the glucose in mammalian cell, which is closely correlated with metabolism. There are three major types of Gluts.The first, Glutl to Glut4 mainly transport glucose; The second, Glut5, Glut7, Glut9, Glut11 mainly transport fructose; The third, Glut6, Glut8, Glut10, Glut12 and HMIT, the effect of which is undefined. Abnormal overexpression of ObR was observed in pancreatic cancer, gastric carcinoma, ovarian cancer, cervical cancer, lung cancer and nasopharyngeal carcinoma tissues.In primary gastric malignant lymphoma (including DLBCL and mucosa-associated lymphoid tissue, MALT),18F-FDG uptake is related to GLUT1 expression and tumor histological grade.The aim of the present study was to investigate the effect of leptin on glucose uptake of T cell lymphma, explore the mechnism and attempt to discover a new targeting therapy scheme.1. Human TCL cell Molt-3 was treated with various concentrations of leptin for different time periods. Cell viability was detected by the CCK-8 assay; glucose uptake was evaluated by Glucose (HK) Assay Kit. Transportion of Glutl to the surface membranes of cells was evaluated via extraction of cell membrane proteins and western blotting analysis. Expression levels of ObR and Gluts were examined by quantitative PCR and western blotting.2. Data of TCL cases was collected. ObR, Glut1 and Glut4 expressions in TCL and RLH tissues were detected by immunohistochemical analysis. Then we investiated the correlation between ObR expression and clinical characteristics.Part I The role of leptin and its receptor in glucose metabolism of T-tymphoma cell Molt-3Objective:Glucose is the major energy resource to maintain cell proliferation and homeostasis. In malignancy, glucose metabolism plays a even more important role than in nomal tissue, because of the faster cell growth and larger demand of calories of malignant cells. Glucose metabolism not only involves in proliferation and apoptosis of tumor cells, but also affects tumor prognosis. In acute lymphoblastic leukemia (ALL), inhibition of glycolysis accelerated glucocorticoids induced tumor cells death. The aim of the present study was to investigate the effect of leptin on the glucose uptake of Human TCL cell Molt-3 and attempt to discover a new targeting therapy scheme.Materials and Methods:1. Co culture with Molt-3 cells and leptin2. CCK-8 method to detect cell proliferation3. Glucose (HK) Assay Kit to detect intracellular glucose concentration4. RNA extraction and RT-PCR5. Cell membrane and total protein extraction and Western blot analysis6. Transfection of s/RNA for ObR into Molt-3 cells, evaluation of glucose uptake and ObR, Glutl expression in Molt-3 cells after the transfection7. Statistical analysisResults:1. Molt-3 cells were initially serum-starved for 24 h and then stimulated with different doses of recombinant leptin (0,10,100,200 ng/mL) for different time periods, leptin induced growth of Molt-3 cells (P< 0.05), especially culcured for a longer time.2. Stimulation of Molt-3 cells with leptin induced a dose-dependent increase in the uptake of glucose after 30min of incubation. And after 48h stimulation with leptin, the increased glucose uptake was observed.(P< 0.05)3. A time-dependent increase in the amount of Glut 1 presenting at the cell surface was observed after incubation with 100 ng/ml leptin. The effect of leptin was maximal after 30 min (P< 0.05).4. Following treatment with 100ng/ml leptin for 48h, the expressions of Glutl at mRNA and protein level in Molt-3 cells was upregulated (P< 0.05). While no significant difference in Glut4 and ObR expression was observed between the leptin-treated and the untreated cells.5. si RNA for ObR was transfected into Molt-3 cells, which notably decreased Ob-R and Glutl expression and inhibited glucose uptake in Molt-3 cells(P< 0.05).Conclusions:1. Leptin increase the proliferation of TCL cell Molt-3.2. Leptin stimulated TCL cell glucose uptake.3. Leptin exerted the above mentioned effects via promoting recruitment and expression of Glutl.Part â…¡ The expression of ObR and GLUT1 in T cell lymphoma and its clinical implicationsObjective:T cell lymphomas (TCL) originated from T-cells or NK-cells at various developmental stages account for approximately 10-15% of cases of non-Hodgkin lymphoma (NHL). Compared to malignancies derived from B-cell, T cell lymphomas are more resisitant to conventional treatments. Thus it is necessary to investigate biochemical metabolism characteristics and mechanisms of malignant T cells, that may provide novel therapies for patients suffering the aggressive disease. In the present study, we collected the data and pathological specimens of TCL cases,then investigated the expression of ObR, Glutl and Glut4 in TCL samples and its clinical implications.Materials and Methods:1. Collection of the data and pathological specimens of TCL cases2. Detection of ObR, Glutl and Glut4 expressions in TCL and Reactive lymphoid hyperplasia(RLH) tissues by immunohistochemical analysis3. Fisher exact probability analysis of correlation between ObR expression and other clinical characteristics4. Cox regression analysis of the relationship between ObR expression and the prognosisResults:1.36 cases of denovo diagnosed TCL and 18 cases of RLH cases between 2008 and 2013 were collected. The median age of the TCL patients is 62 years and the three-year survival rate is 14.0%,the median survival time is 16.5 months.2. The expressions of ObR were significantly higher in TCL than those of RLH (58.3% vs 22.2%, P=0.012)3. ObR expression showed a significant association with Glutl (P=0.007) rather than Glut4 (P=0.292). Furthermore ObR overexpression did not show significant associations with age, sex, performance status, Ann Arbor Stage, lactate dehydrogenase (LDH) levels B-symptom or combined diabetes.4. Univariate survival analysis indicated that coexpression of ObR and Glutl and age older than 60 affect the prognosis of TCL. In multivariate analysis, coexpression of ObR and Glutl was identified as an independent adverse prognostic factor for TCL (HR=3.420,95%CI 1.293-9.049,P=0.013)Conclusions:1. The expressions of ObR were significantly higher in TCL than in RLH.2. There exists correlation between ObR and Glutl expression.3. TCL is a disease with grave prognosis. Coexpression of ObR and Glutl is an independent adverse prognostic factor in TCL. |
