Ikezoe Takayuki, Chen Sophie, Saito Tsuyako, Asou Hiroya, Kyo Taiichi, Tanosaki Sakae, Heber David, Taguchi Hirokuni, Koeffler H Phillip
Department of Medicine, Kochi Medical School, Nankoku, Kochi 783-8505, Japan.
Int J Oncol. 2003 Oct;23(4):1203-11.
PC-SPES is an eight herbal mixture which has been shown to be active against prostate cancer cells in vitro as well as in patients. In this study, we discovered that it has anti-leukemia activity. HL-60, NB4, U937 and THP-1 human acute myeloid leukemia cells were cultured in the presence of various concentrations of PC-SPES (0.06-0.5 micro l/ml) for 4 days, and cell numbers were counted by Trypan blue exclusion. PC-SPES inhibited proliferation of these cells with an ED50 of 0.17, 0.09, 0.18, 0.32 micro l/ml, respectively. In clonogenic assay, PC-SPES inhibited growth of HL-60 cells (ED50, 0.043 micro l/ml). On the other hand, PC-SPES (0.1 micro l/ml) stimulated growth of normal myeloid committed stem cells (CFU-GM) by 1.4-fold of control (p=0.03). Anti-leukemia effects also occurred against freshly isolated leukemia cells from acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) patients. Interestingly, when PC-SPES was combined with ATRA, the antiproliferative effect was markedly enhanced. For example, PC-SPES (0.125 micro l/ml) or ATRA (10(-8) mol/l) inhibited growth of HL-60 cells after 4 days of culture, by approximately 40 and 30%, respectively; simultaneous treatment with both, suppressed growth by 80%. In addition, PC-SPES induced differentiation of HL-60 and NB4 cells, as measured by expression of CD11b and reduction of NBT. ATRA synergistically enhanced this activity. For example, either PC-SPES (0.5 micro l/ml) or ATRA (10(-8) mol/l) induced 23 and 18% of HL-60 cells, respectively to express CD11b on day 2 of culture; and when both were combined, 60% of HL-60 cells were stimulated to express CD11b antigen. Furthermore, PC-SPES (0.5 micro l/ml) produced apoptosis of HL-60 and NB4 cells, as measured by TUNEL assay, with 17% of HL-60 cells and 52% of NB4 cells becoming apoptotic on their third day of culture. Importantly, PC-SPES stimulated expression of the novel myeloid specific transcription factor C/EBPepsilon in HL-60 and NB4 cells. Taken together, PC-SPES inhibits growth and induces differentiation and apoptosis of myeloid leukemia cells, and enhances the antiproliferative and prodifferentiative effects of ATRA on these cells. PC-SPES might be useful with ATRA for treatment of patients with acute promyelocytic leukemia (APL), and it could have a role in other types of cancers including MDS.
PC-SPES是一种由八种草药组成的混合物，已证明其在体外以及对患者的前列腺癌细胞具有活性。在本研究中，我们发现它具有抗白血病活性。将HL-60、NB4、U937和THP-1人急性髓系白血病细胞在不同浓度的PC-SPES（0.06 - 0.5微升/毫升）存在下培养4天，通过台盼蓝排斥法计数细胞数量。PC-SPES抑制这些细胞增殖的半数有效剂量（ED50）分别为0.17、0.09、0.18、0.32微升/毫升。在集落形成试验中，PC-SPES抑制HL-60细胞生长（ED50，0.043微升/毫升）。另一方面，PC-SPES（0.1微升/毫升）使正常髓系定向干细胞（CFU-GM）的生长比对照组增加了1.4倍（p = 0.03）。对急性髓系白血病（AML）和骨髓增生异常综合征（MDS）患者新鲜分离的白血病细胞也有抗白血病作用。有趣的是，当PC-SPES与全反式维甲酸（ATRA）联合使用时，抗增殖作用明显增强。例如，培养4天后，PC-SPES（0.125微升/毫升）或ATRA（10^(-8)摩尔/升）分别使HL-60细胞生长抑制约40%和30%；两者同时处理时，生长抑制达80%。此外，通过CD11b表达和硝基蓝四氮唑（NBT）还原测定，PC-SPES诱导HL-60和NB4细胞分化。ATRA协同增强了这种活性。例如，培养第2天，PC-SPES（0.5微升/毫升）或ATRA（10^(-8)摩尔/升）分别诱导23%和18%的HL-60细胞表达CD11b；两者联合时，60%的HL-60细胞被刺激表达CD11b抗原。此外，通过TUNEL测定，PC-SPES（0.5微升/毫升）使HL-60和NB4细胞发生凋亡，培养第3天时，17%的HL-60细胞和52%的NB4细胞发生凋亡。重要的是，PC-SPES刺激HL-60和NB4细胞中新型髓系特异性转录因子C/EBPε的表达。综上所述，PC-SPES抑制髓系白血病细胞生长，诱导其分化和凋亡，并增强ATRA对这些细胞的抗增殖和促分化作用。PC-SPES与ATRA联合可能对急性早幼粒细胞白血病（APL）患者的治疗有用，并且它可能在包括MDS在内的其他类型癌症中发挥作用。
