Generation of a Genetically Engineered Aggressive Nk-Cell Leukemia Cell Line with Stable IL2 Expression.

ABSTRACT

Introduction: Aggressive NK-cell leukemia (ANKL) is a highly aggressive disease with extremely poor prognosis. A few malignant NK cell lines reflecting ANKL biology have been generated; however, these NK cell lines require the inclusion of exogeneous IL2 in the culture medium continuously, which increases the cost of cell culture significantly. Methods: IL2 coding sequenced was cloned into MSCV-IRES-YFP (PMIY) vector by directional PCR-cloning. IL2 was ectopically expressed in KHYG1 cell line through retroviral transduction. The transduced cells were cultured in limiting IL2 concentrations during which they were quantified with flow cytometry in regular time intervals to track the transduced population. IL2 transduced KHYG1 cells were then sorted to generate IL2-KHYG1 cells. PRDM1 was ectopically expressed in IL2-KHYG1 cells through retroviral transduction. Trypan blue count was performed to test proliferation of IL2-KYHG1 cells in the absence of IL2. Results: IL2-KHYG1 cells were enriched (from ~7% to ~16% YFP+ cells) during cell culture in limiting (6.25IU) IL2 concentrations. Complete removal of IL2 further enriched the transduced portion to 27% YFP-positivity, which did not increase with additional culturing. IL2 expressing KHYG1 cells were further enriched by sorting transduced IL2-KHYG1 cells with high level IL2 expression. IL2-KHYG1 cells survived and continued to grow without IL2. IL2-KHYG1 cells were transduced successfully using a PRDM1 construct having GFP as a marker under cell culture conditions having no IL2. Conclusion: IL2-KHYG1 cell line may decrease the cost associated with culturing ANKL cell lines, and it may facilitate in vitro investigation of the molecular basis of this malignancy.