Kogoshi Hanae, Tohda Shuji, Fu Lu, Koyama Takatoshi, Nara Nobuo
Department of Laboratory Medicine, Tokyo Medical and Dental University, Bunkyo-Ku, Tokyo 113-8519, Japan.
Oncol Rep. 2005 Sep;14(3):723-6.
The effect of the recombinant Notch ligand proteins Jagged1 and Delta1 on drug-sensitivity of leukemia and lymphoma cells was examined. Four acute myeloid leukemia (AML) cell lines were cultured in ligand-coated wells and control wells, with cytosine arabinoside (Ara-C), doxorubicin, or mitoxantrone, and nine lymphoid leukemia or lymphoma cell lines were cultured with dexamethasone. The growth was evaluated with a colorimetric assay. The drug-induced growth suppression was slightly reduced by the ligand stimulation in 4 out of 17 combinations of cells versus drugs, such as NB4 cells versus Ara-C. In the remainder, the ligands did not significantly affect the drug-sensitivity. To investigate the possible molecular mechanism of the protective effect, the influence of Jagged1 on Ara-C-induced activation of caspase-3 and PARP, and dephosphorylation of NF-kappaB was examined in NB4 cells. However, Jagged1 did not obviously affect the activation and dephosphorylation. It is known that stromal cells reduce drug-induced cytotoxicity of leukemia cells. According to our results, the role of Notch ligands in the stroma-mediated resistance seems to be minor and occurs only in a limited context. However, the ligand-coated culture-plates are more similar to the microenvironment in human bone marrow than ordinary plates. We will further examine the clinical usefulness of the drug-sensitivity test using the ligand-coated plates.
研究了重组Notch配体蛋白Jagged1和Delta1对白血病和淋巴瘤细胞药物敏感性的影响。将四种急性髓系白血病（AML）细胞系分别培养于包被配体的孔板和对照孔板中，加入阿糖胞苷（Ara-C）、多柔比星或米托蒽醌，将九种淋巴细胞白血病或淋巴瘤细胞系培养于地塞米松中。采用比色法评估细胞生长情况。在17种细胞与药物的组合中，有4种组合（如NB4细胞与Ara-C），配体刺激使药物诱导的生长抑制略有降低。其余组合中，配体对药物敏感性无显著影响。为探究保护作用可能的分子机制，在NB4细胞中检测了Jagged1对Ara-C诱导的半胱天冬酶-3和PARP激活以及核因子κB去磷酸化的影响。然而，Jagged1并未明显影响其激活和去磷酸化。已知基质细胞可降低药物诱导的白血病细胞毒性。根据我们的结果，Notch配体在基质介导的耐药中的作用似乎较小，且仅在有限的情况下发生。然而，包被配体的培养板比普通板更类似于人类骨髓中的微环境。我们将进一步研究使用包被配体板进行药物敏感性试验的临床实用性。
