Das Jharna R, Fryar-Tita Elizabeth B, Zhou Yanfei, Green Sidney, Southerland William M, Bowen Donnell
Department of Pharmacology, College of Medicine, Howard University, Washington, DC 20059, USA.
Anticancer Res. 2007 Nov-Dec;27(6B):3791-9.
Breast cancer is a leading cause of morbidity and mortality in women in developed countries and in increasingly developing countries. In general, estrogen receptor (ER)-positive breast cancers have a better prognosis and are often more responsive to anti-estrogen therapy. Unfortunately, ER-negative breast cancers are more aggressive and unresponsive to anti-estrogens. The aim of this investigation was to evaluate the 5-fluorouracil (5-FU) and methotrexate (MTX) combination to determine the most effective regimen considering the mechanism of action in treating ER-negative human breast cancer cells and at the same time mitigating methotrexate cytotoxicity in human bone marrow cells.
In order to determine the sequence-dependent interaction between MTX and 5-FU on proliferation, cell viability was carried out using the Quick Cell Proliferation Assay by exposing the human estrogen negative (MDA-MB-436 and Hs-578T) and bone marrow (HS-5) cells to: (i) MTX and 5-FU alon; (ii) MTX 2 h prior to 5-FU (MTX/5-FU; (iii) 5-FU 2 h prior to MTX (5-FU/MTX).
The growth rate in MDA-MB-436 was 23.5 +/- 3.98%, in Hs-578T 30 +/- 5.9% and HS-5 32 +/- 3.1% of the control for MTX/5-FU. Whereas the growth rate in MDA-MB-436 was 28.5 +/- 4.1%, in Hs-578T 34.7 +/- 3.5% and HS-5 68.6 +/- 6.3% of the control for 5-FU/MTX combinations. The later combination exhibits significant protection against MTX cytotoxicity in bone marrow and at same time maintained maximum cytotoxicity in estrogen negative breast cancer cell lines. The findings were further supported by cell flow cytometry, apoptosis and Western blot analysis data.
The combination of 5-FU/MTX effectively maintains the maximum inhibitory effect of MTX in ER-negative breast cancer and protects against MTX cytotoxicity in human bone marrow.
乳腺癌是发达国家以及越来越多发展中国家女性发病和死亡的主要原因。一般来说，雌激素受体（ER）阳性乳腺癌预后较好，且通常对抗雌激素治疗反应更敏感。不幸的是，ER阴性乳腺癌侵袭性更强，对抗雌激素药物无反应。本研究的目的是评估5-氟尿嘧啶（5-FU）与甲氨蝶呤（MTX）联合用药情况，根据其作用机制确定治疗ER阴性人乳腺癌细胞的最有效方案，同时减轻甲氨蝶呤对人骨髓细胞的细胞毒性。
为了确定MTX和5-FU之间对增殖的序列依赖性相互作用，通过快速细胞增殖试验检测细胞活力，将人雌激素阴性（MDA-MB-436和Hs-578T）和骨髓（HS-5）细胞暴露于：（i）单独的MTX和5-FU；（ii）MTX在5-FU前2小时（MTX/5-FU）；（iii）5-FU在MTX前2小时（5-FU/MTX）。
对于MTX/5-FU组合，MDA-MB-436的生长率为对照的23.5±3.98%，Hs-578T为30±5.9%，HS-5为32±3.1%。而对于5-FU/MTX组合，MDA-MB-436的生长率为对照的28.5±4.1%，Hs-578T为34.7±3.5%，HS-5为68.6±6.3%。后一种组合在骨髓中对MTX细胞毒性表现出显著保护作用，同时在雌激素阴性乳腺癌细胞系中保持最大细胞毒性。细胞流式细胞术、凋亡和蛋白质印迹分析数据进一步支持了这些发现。
5-FU/MTX组合有效维持了MTX对ER阴性乳腺癌的最大抑制作用，并保护人骨髓免受MTX细胞毒性。
