Studies On Effects Of HC56 Gene On Proliferation And Apoptosis Of Lymphoma/Leukemic Cells

OBJECTIVE: Recent studies indicated that human chromosome l pl3.13 is related to cancerogenesis of many cancers including leukemia and lymphoma. Series of hepatic related gene include HC56 HC7 1 and HC9O,etc,which were novel diseases related genes cloned from human chromosome l7pl3.3 with positional cloning technique by National Laboratory for Oncogenes and Related Genes of Shanghai Cancer Institute. In the present studies, using gene transfer technique in vitro, the effects of HC56 . HC7 1 and HC9O gene on growth of leukemic and lymphoma cells when its overexpression were observed; Our investigation focus on the effects of exogenous HC56 gene products on proliferation and apoptosis of leukemic and lymphoma cells, as well as on leukemic and lymphoma cells sensitivity to chemotherapeutic drugs in order to understand the biologic function of HC gene series, above all, HC56 gene. Furthermore, It willprovide experimental evidences for gene therapy of leukemia and lymphoma. METHODS: Exogenous HC56 HC71 and HC9O gene were transfected into human T-cell lymphoina cell line Jurkat cells-, B-cell lymphoma cell line Raji cells and acute myeloid leukemia cell line K562 cells by medium with liposome; The effects of transient expression of the Hc56 gene on cell viability were observed by trypan blue dye exclusion test. HC56 gene was transfected into Jurkat and Raji cells, the cells stably expressing exogenous HC5 6 gene were screened by G4 18. The effects of HC56 gene products on proliferation of Jurkat and Raji cells were observed by counting live cells with trypan blue dye exclusion test, plotting growth curve and assaying colony formation in soft agar. HC56 gene was transfected into human T-cell lymphoma Jurkat cells and B-cell lymphoma Raji cells, the effects of HC56 gene products on apoptosis of cells were observed by means of flow cytometry-. TUNEL and Hoechst 33258 staining. HC56 gene was transfected into Jurkat cells, and the sensitivity of Jurkat cells stably expressing HC56 gene screened with 6418 to topoisomerase II inhibitor etoposide (VP 16) was investigated by MTT assay. RESULTS: The viability of Jurkat, Raji and K562 cells at 24 48-. 72 and 96 hours after HC56 gene transiently transfected was inhibited significantly(p O.Ol) as compared with control cells transfected with PBKICMV vector ; The viability of Jurkat cells at 24-. 48-i 72 and 96 hours after HC7 1 gene transiently transfected was inhibited significantly(p<0.O1) as compared with that of control cells transfected with PBKICMV vector; The viability of Jurkat cells at 24-. 48 and 72 hours except at 96 hours after HC9O gene transiently transfected was not inhibited significantly(p>0.05) as compared with that of control cells transfected with PBK/CMV vector; â‘¡Stable expression of exogenous HC56 gene in Jurkat and Raj i cells could inhibit proliferation of cells, obviously slow the growth rate, make the cell double-time extended significantly (p