Influence of Biological Character of Acute Lymphoblastic Leukemia Cell Linet after Overexpression of C/EBPa and PU.1

Objective: To observe the influence of biological character of acute lymphoblastic leukemia cell line Jurkat in vitro and in vivo after overexpression of C/EBPa and PU.1.

Methods: To establish transducing plasmids, using 293T cells to package lentiviral vector and to transfect Jurkat cell line. Flow cytometry is used to analyze the expression of membrane cluster differentiation antigen, apoptosis rate, proliferation and cell cycle of cells. Cell morphology and Q-PCR was used to analyze the changes of cell morphology and molecule gene. Six to eight weeks old immunodeficiency (NSI) mice were transplanted by tail vein injected with 2x10⁶ cells after transduction. To observe the biological behavior and survival time, using Flow cytometric, cell morphology, pathological HE staining, immunohistochemistry to analyze the invasion of leukemia cells.

Results: The expression of CD3 (mark antigen of lymphocyte) fall as low as 20% after overexpression of C/EBPa and PU.1, CD11b (mark antigen of myeloid cell) increase as high as 30%, which has significant difference with Jurkat-gfp group. The apoptosis rate has significantly increase, proliferation rate has significantly decrease after overexpression of C/EBPa, which blocked in S period. Adding myeloid cytokine (GM-CSF, M-CSF, IL-3, FLT-3L,100ng/mL) on the supernatant of transduction cells, Jurkat cells can be reprogrammed to attached cells from suspension after overexpression of C/EBPa and PU.1 in the 5th day. Attached cells can chemotaxis and consuming yeast. Cell multicore and small amount of purple particles in cytoplasm has observed in Jurkat after overexpression of C/EBPa and PU.1, high expression of myeloid gene (CD14, CD64) and low expression of lymphocyte gene (BCL-11B, GATA-3) has observed in cells after transduction. All the mice have leukemia between 1 to 2 months after injection with transfected cells. The survival time is longest in overexpression of C/EBPa group, which shows significant difference (P<0.001). Cells of peripheral blood, liver, spleen and bone marrow can partly transduce to myeloid cells after overexpression of C/EBPa and PU.1, additionally, the expression of CD11b is observed in liver and spleen cells by immunohistochemistry.

Conclusion: Jurkat cells can be partly reprogrammed to monocyte- macrophages, while with the help of myeloid cytokines, it can be reprogrammed to macrophages with chemotactic and phagocytic function. Jurkat cells can be partly reprogrammed to monocyte- macrophages in vivo and prolong the survival time after overexpression of C/EBPa and PU.1.