Han Z C, Lu M, Li J, Defard M, Boval B, Schlegel N, Caen J P
Institut des Vaisseaux et du Sang, University of Paris VII, France.
Blood. 1997 Apr 1;89(7):2328-35.
The effects of platelet factor 4 (PF4) on the viability and chemosensitivity of normal hematopoietic cells and cancer cell lines were studied to determine the mechanisms whereby PF4 functions as either an inhibitor or a protector and to evaluate its clinical significance. Two other chemokines, interleukin-8 (IL-8) and neutrophil-activating peptide-2 (NAP-2), were also studied in comparison to PF4. Using a tetrazolium salt assay for cell viability, we observed that PF4 at 1 to 50 microg/mL supported the viability of normal human bone marrow cells. Approximately 45% of cells cultured for 48 hours survived, whereas 80% or more survived in the presence of PF4 5 microg/mL. PF4 also supported the viability of CD34+ cord blood (CB) cells and protected them from apoptosis induced by transforming growth factor beta1 (TGFbeta1) and cytotoxic drugs. Pretreatment of CD34+ cells by PF4, but not by TGFbeta1, caused an increase in the number of megakaryocyte colonies after these cells were replated in secondary cultures. Flow cytometry analysis showed that when CD34+ cells were preincubated with PF4 or TGFbeta1 for 12 days in hematopoietic growth factor-rich medium, an increased number of remaining CD34+ cells was observed only for PF4-treated cells. Furthermore, PF4 significantly reduced the chemosensitivity of bone marrow cells, as shown by its ability to increase the 50% inhibition concentration (IC50) of several cytotoxic agents. Like PF4, IL-8 and NAP-2 at 0.1, 0.6, and 1 microg/mL supported the survival of myeloid progenitors, including colony-forming units granulocyte, erythroblast, monocyte, megakaryocyte (CFU-GEMM), CFU-megakaryocyte (CFU-MK), CFU-granulocyte/macrophage (CFU-GM), and burst-forming units-erythroblast (BFU-E), and reduced their sensitivity to the toxicity of etoposide (ETP). Protamine sulfate at 1 to 100 microg/mL showed no such activity of PF4. Interestingly, the three chemokines failed to affect significantly the viability and chemosensitivity of three leukemic and two other tumor cell lines. Based on these results, we conclude for the first time that PF4 and IL-8 and NAP-2 support the survival of normal hematopoietic precursors and protect them from the toxicity of chemotherapeutic agents. Because such activities are unique to normal hematopoietic cells but not to the cancer cell lines evaluated, a potential clinical application of these molecules in the treatment of cancer is suggested.
研究了血小板因子4（PF4）对正常造血细胞和癌细胞系活力及化学敏感性的影响，以确定PF4作为抑制剂或保护剂发挥作用的机制，并评估其临床意义。还将另外两种趋化因子，即白细胞介素-8（IL-8）和中性粒细胞激活肽-2（NAP-2）与PF4进行了比较研究。使用四氮唑盐法检测细胞活力，我们观察到1至50μg/mL的PF4可维持正常人骨髓细胞的活力。培养48小时的细胞中约45%存活，而在5μg/mL PF4存在的情况下80%或更多的细胞存活。PF4还可维持CD34+脐血细胞的活力，并保护它们免受转化生长因子β1（TGFβ1）和细胞毒性药物诱导的凋亡。PF4预处理CD34+细胞（而非TGFβ1预处理），可使这些细胞在二次培养重新接种后巨核细胞集落数量增加。流式细胞术分析表明，当CD34+细胞在富含造血生长因子的培养基中与PF4或TGFβ1预孵育12天时，仅PF4处理的细胞中剩余的CD34+细胞数量增加。此外，PF4显著降低了骨髓细胞的化学敏感性，表现为它能够提高几种细胞毒性药物的50%抑制浓度（IC50）。与PF4一样，0.1、0.6和1μg/mL的IL-8和NAP-2可维持髓系祖细胞的存活，包括粒细胞、成红细胞、单核细胞、巨核细胞集落形成单位（CFU-GEMM）、巨核细胞集落形成单位（CFU-MK）、粒细胞/巨噬细胞集落形成单位（CFU-GM）和红细胞爆式集落形成单位（BFU-E），并降低它们对依托泊苷（ETP）毒性的敏感性。1至100μg/mL的硫酸鱼精蛋白未表现出PF4的这种活性。有趣的是，这三种趋化因子对三种白血病细胞系和另外两种肿瘤细胞系的活力和化学敏感性均无显著影响。基于这些结果，我们首次得出结论，PF4、IL-8和NAP-2可维持正常造血前体细胞的存活，并保护它们免受化疗药物的毒性。由于这些活性是正常造血细胞所特有的，而在所评估的癌细胞系中并非如此，因此提示这些分子在癌症治疗中具有潜在的临床应用价值。
