电转人IL6受体基因对急性白血病细胞生物学特性的影响

Influence of a cDNA encoding human interleukin-6 receptor on the original properties of LT12 leukemic cells

为了探索重组ＩＬ６－ＰＥ４０融合蛋白靶向杀伤白血病的效应，我们已成功地将编码人ＩＬ６Ｒ的全长ｃＤＮＡ转入ＢＮＭＬ大鼠急性早幼粒细胞白血病ＬＴ１２细胞中。本文研究了ＩＬ６ＲｃＤＮＡ转入ＬＴ１２细胞后对该细胞原有生物学特性的影响。结果表明：①ＬＴ１２－ＩＬ６Ｒ￣＋细胞与原代细胞五种酶学组化无任何区别；②ＬＴ１２－ＩＬ６Ｒ￣＋细胞不仅高表达ＩＬ６Ｒ而且仍保持原有的表面抗原性质，如与ＲＭ－１２４单抗结合；③在白血病细胞体内外克隆源试验中，两种细胞系等同；④更重要的是ＬＴ１２－ＩＬ６Ｒ￣＋细胞的致瘤特性无异于ＬＴ１２原代细胞。证明ＬＴ１２－ＩＬ６Ｒ￣＋仍为急性早幼粒细胞白血病。

Recently we have reported that a full cDNA encoding for human interleu- kin-6 receptor(IL6R)has been transfered and stably expressed in LT12 cells having nodetective level of IL6R,a subline from BNML rat acute promyelocytic leukemia model inorder to investigate the selective kill effect of recombinant interleukin6-pseudomonas exo- toxin fusion proteinon leukemic cells expressing high level of IL6R. The aim of thiswork was to define whether the high expression and stable integration of human IL6RcDNA in LT12 cells willchange the original biological properties of LT12 cells, especiallythe tumorgencity.Cytochemical characteristics revealed that LT12-IL6R￣+ cells were stillpromyelocyte, ie,peroxidase reaction(+),esterase(+),sudan black(++ +), acid phospha- tase(++)and alkaline phosphatase (-),that did not differ with those of LT12-IL6R￣-In addition to high level of IL6R, LT12-IL6R￣+ cells showed the same typical fluorescenceintensity as LT12-IL6R￣-measured by FITC-conjugate RM-124 MCA with FACSD-II cellsorting. Two impOrtant clongenic properties of leukemic cells both in vitro and in vivowere also maintained in LT12-IL6R￣+ cells evaluated with leukemia colony-forming unitand spleen colony assays for clongenic leukemic cells. There were no difference in leukemiccell load caused by LT12-IL6R￣+ and LT12-IL6R￣-in spleen and liver. The median survivaltime, a more important and sensitive method to elucidate the tumor gencity, recorded hadnot any difference between LT12-IL6R￣+ and LT12-IL6R￣-cells. Thus it can be concludedthat LT12-L6R￣+ cells retained the original promyelocytic leukemic nature of LT12-IL6R￣-cells.