Mohammad R M, Katato K, Almatchy V P, Wall N, Liu K Z, Schultz C P, Mantsch H H, Varterasian M, al-Katib A M
Karmanos Cancer Institute, Wayne State University School of Medicine, Department of Medicine, Detroit, Michigan 48201, USA.
Clin Cancer Res. 1998 Feb;4(2):445-53.
We have previously reported that bryostation 1 (Bryo 1) induces differentiation of chronic lymphocytic leukemia (CLL) in vitro to a hairy cell (HC) stage. This study tests the hypothesis that Bryo 1-differentiated CLL cells are more susceptible to 2-chlorodeoxyadenosine (2-CdA) than parent CLL cells. A recently established EBV-negative CLL line (WSU-CLL) from a patient resistant to chemotherapy including fludarabine was used to test this hypothesis. Both Bryo 1 (10-1000 nM) and 2-CdA (5.6-22.4 microM) exhibited a dose-dependent growth inhibitory effect on the WSU-CLL cell line. In vitro, the sequential exposure to Bryo 1 (100 nM for 72 h) followed by 2-CdA (11.2 microM) resulted in significantly higher rates of growth inhibition than either agent alone. Changes in immunophenotype, enzymes, lipids, proteins, and the DNA of WSU-CLL cells were studied before and after Bryo 1 treatment. Bryo 1 induced a positive tartrate-resistant acid phosphatase reaction and two important markers, CD11c and CD25, after 72 h of culture, confirming the differentiation of CLL to HC. The Fourier transformation infrared spectroscopic analysis showed that the amount of membrane lipids significantly increased in Bryo 1-treated cells compared to controls after 24 h, whereas the protein content, as well as the DNA content, decreased. This finding supports the change of CLL to HC. To evaluate the in vivo efficacy of Bryo 1 and 2-CdA, we used a xenograft model of CLL in WSU-CLL-bearing mice with severe combined immune deficiency. s.c. tumors were developed by injection of 10(7) WSU-CLL cells, and fragments were then transplanted into a new batch of severe combined immunodeficient mice. Bryo 1 and 2-CdA at the maximum tolerated doses (75 micrograms/kg i.p. and 30 mg/kg s.c., respectively) were administered to the mice at different combinations and schedules. The survival in days, the tumor growth inhibition ratio, the tumor growth delay, and the log10 kill of the mice treated with Bryo 1 followed by 2-CdA were significantly better than the control and other groups. We conclude that the sequential treatment with Bryo 1 followed by 2-CdA resulted in higher antitumor activity and improved animal survival.
我们之前曾报道过苔藓抑瘤素1（Bryo 1）可在体外诱导慢性淋巴细胞白血病（CLL）分化至毛细胞（HC）阶段。本研究检验了以下假设：经Bryo 1分化的CLL细胞比亲代CLL细胞对2-氯脱氧腺苷（2-CdA）更敏感。采用从一名对包括氟达拉滨在内的化疗耐药患者中最近建立的EBV阴性CLL细胞系（WSU-CLL）来验证这一假设。Bryo 1（10 - 1000 nM）和2-CdA（5.6 - 22.4 microM）对WSU-CLL细胞系均表现出剂量依赖性生长抑制作用。在体外，先给予Bryo 1（100 nM，处理72小时），随后给予2-CdA（11.2 microM），其生长抑制率显著高于单独使用任一药物。研究了Bryo 1处理前后WSU-CLL细胞的免疫表型、酶、脂质、蛋白质及DNA的变化。培养72小时后，Bryo 1诱导出阳性抗酒石酸酸性磷酸酶反应以及两个重要标志物CD11c和CD25，证实CLL已分化为HC。傅里叶变换红外光谱分析显示，与对照组相比，Bryo 1处理24小时后的细胞中膜脂含量显著增加，而蛋白质含量和DNA含量则下降。这一发现支持了CLL向HC的转变。为评估Bryo 1和2-CdA的体内疗效，我们在重度联合免疫缺陷的荷WSU-CLL小鼠中建立了CLL异种移植模型。通过注射10⁷个WSU-CLL细胞形成皮下肿瘤，然后将肿瘤片段移植到另一批重度联合免疫缺陷小鼠体内。以最大耐受剂量（分别为腹腔注射75微克/千克和皮下注射30毫克/千克）将Bryo 1和2-CdA以不同组合和给药方案给予小鼠。先给予Bryo 1后给予2-CdA治疗的小鼠的存活天数、肿瘤生长抑制率、肿瘤生长延迟及对数杀灭率均显著优于对照组和其他组。我们得出结论，先给予Bryo 1后给予2-CdA的序贯治疗具有更高的抗肿瘤活性并提高了动物存活率。
