He Peng-Cheng, Zhang Mei, Wu Di, Xu Hui, Cai Rui-Bo, Liu Ya-Lin
Department of Hematology, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, P. R. China.
Ai Zheng. 2006 Dec;25(12):1477-82.
BACKGROUND & OBJECTIVE: More than 90% patients with acute promyelocytic leukemia (APL) achieve clinical complete remission by using all-trans retinoic acid (ATRA). However, the rapid development of ATRA-resistance has become a problem in treating APL. Many researches indicate that the mechanism of ATRA-resistance is related to lack of some proteins synthesized by interferon (IFN). This study was to explore the possibility and the possible mechanism of treating ATRA-resistant APL with IFN in combination with ATRA.
Interferon-gamma (IFNgamma) alone or IFNgamma combined with ATRA was used to treat ATRA-sensitive cell line NB4 and ATRA-resistant cell line MR2. Cell proliferation was tested by MTT assay. Light microscope and NBT test were used to evaluate cell differentiation. The expression of promyelocytic leukemia (PML) protein was observed by indirect immune fluorescent method.
On the 8th day, the growth inhibition rates of NB4 cells and MR2 cells were significantly higher in combination group than in IFNgamma group and ATRA group (95.2% vs. 68.0% and 85.0%, P<0.05; 51.5% vs. 24.1% and 4.3%, P<0.05). On the 3rd day, the positive rates of NBT in NB4 cells and MR2 cells were significantly higher in combination group than in IFNgamma group and ATRA group (93.3% vs. 19.3% and 74.7%, P<0.05; 31.5% vs. 16.8% and 5.2%, P<0.05). After treatment of IFNgamma, the fluorescent particles in NB4 and MR2 cell nuclei were obviously increased as compared with those in control group.
IFNgamma and ATRA have synergistic inhibitory effect on the proliferation of NB4 cells and MR2 cells, and can partially induce the differentiation of ATRA-resistant MR2 cells.
超过90%的急性早幼粒细胞白血病（APL）患者使用全反式维甲酸（ATRA）可实现临床完全缓解。然而，ATRA耐药的快速发展已成为APL治疗中的一个问题。许多研究表明，ATRA耐药机制与缺乏一些由干扰素（IFN）合成的蛋白质有关。本研究旨在探讨IFN联合ATRA治疗ATRA耐药APL的可能性及可能机制。
使用γ干扰素（IFNγ）单独或IFNγ联合ATRA治疗对ATRA敏感的细胞系NB4和对ATRA耐药的细胞系MR2。采用MTT法检测细胞增殖。用光镜和NBT试验评估细胞分化。通过间接免疫荧光法观察早幼粒细胞白血病（PML）蛋白的表达。
第8天，联合组NB4细胞和MR2细胞的生长抑制率显著高于IFNγ组和ATRA组（95.2%对68.0%和85.0%，P<0.05；51.5%对24.1%和4.3%，P<0.05）。第3天，联合组NB4细胞和MR2细胞的NBT阳性率显著高于IFNγ组和ATRA组（93.3%对19.3%和74.7%，P<0.05；31.5%对16.8%和5.2%，P<0.05）。IFNγ处理后，与对照组相比，NB4和MR2细胞核内的荧光颗粒明显增加。
IFNγ和ATRA对NB4细胞和MR2细胞的增殖具有协同抑制作用，并可部分诱导ATRA耐药的MR2细胞分化。
