Experimental Study On Chronic Myelogenous Leukemia Cells Vaccine Modified In Vitro With Human Wild-Type P-53,GM-CSF And B7-1 Genes Mediated By Recombinant Adenovirus Vector

Chronic myelogenous leukemia (CML) is a kind of malignantly proliferative disease originated from multipotent hemopoietic stem cells, and manifests itself by extension of myelocytic progenitor pool, overgrowth of myelocytic series and its progenitors. Over 90% cases of CML have a Ph chromosome marker. The year incidence of CML in China is 0.36/hundred-thousand, accounting for 20% of all kinds of leukemias and 95% of all chronic leukemia. It affects people of all age groups, especially those of 30-40 years. Male patients are slightly more than female ones. Without effective treatment, patients can only survive 2 years on the average after diagnosis[l]. Hence, it threatens seriously the life of humans. However, conventional therapeutic methods being used currently, such as chemotherapy, radiotherapy, transplantation of hemopoietic stem cells, all have certain limitations. It, therefore, is needed to develop a new kind of therapy for effective treatment of CML. In Department of Experimental Hematology of Beijing Institute of Radiation Medicine, they constructed a recombinant adenovirus carrying human wild-type p53 gene and tumor immunity-related genes?GM-CSF and B7-1, named as BB- 102, and observed that proliferation of the human laryngocarcinoma cells was 5 inhibited markedly and apoptosis was induced after infection with BB-102. Besides, such infected cells could also induce in Vitro autologous peripheral blood lymphocytes to transform into tumor-killing cytotoxic I lymphocyte (CTL)[2]. Hence, in the present study the effect of cotransduction of human wild-type p53, GM-CSF and B7-1 genes mediated by recombinant adenovirus on apoptogenesis and inununogenecity of chronic myelogeneous leukemia cell line K562 and primary chronic myelogeneous leukemia cells was studied. The CML cell line K562 and primary CML cells were transfected separately with recombinant adenovirus mediating green fluorescent protein (GFP) and BB-102. The transfer efficiency by flow cytometry, the expression of the three genes in K562 cells and primary CML cells , and the inimunogenecity of both kinds of transfected CML cells were tested. Results indicate that the transfer efficiencies for K562 cells and primary CML cells from a patient were 9 1.8% and over 36.2% respectively at 400 MOI. Expression of p53, GM-CSF and B7-1 was demonstrated in K562 cells and primary CML cells. Growth of the infected K562 cells was inhibited, and apoptosis was induced. Immunogenecity of both K562 cells and primary cells transfected with BB-102 was greatly enhanced. Our results indicate that clinical application of the in vitro BB- 102-modified tumor cell vaccine might be feasible and effective in clinical treament of chronic myelogenous leukemia.