Sugiyama T, Sadzuka Y
School of Pharmaceutical Sciences, University of Shizuoka, Japan.
Clin Cancer Res. 1999 Feb;5(2):413-6.
Theanine is a peculiar amino acid existing in green tea leaves, which was previously indicated to enhance the antitumor activity of doxorubicin. In the present study, the effect of combination of theanine with doxorubicin against hepatic metastasis of M5076 ovarian sarcoma was investigated. The primary tumor was significantly reduced by the combined treatment on M5076 transplanted (s.c.) mice. The liver weight of control mice increased to twice the normal level because of hepatic metastasis of M5076. In contrast, the injection of doxorubicin alone or theanine plus doxorubicin suppressed the increase in liver weight and inhibited hepatic metastasis. Moreover, the liver weights and metastasis scores demonstrated that theanine enhanced the inhibition of hepatic metastasis induced by doxorubicin. Furthermore, in vitro experiments indicated that theanine increased the intracellular concentration of doxorubicin remaining in M5076 cells. This action suggests that theanine leads the enhancement of the suppressive efficacy of doxorubicin on hepatic metastasis in vivo. Therefore, it was proved that theanine increased not only the antitumor activity on primary tumor but also the metastasis-suppressive efficacy of doxorubicin. The effect of theanine on the efficacy of antitumor agents is expected to be applicable in clinical cancer chemotherapy.
茶氨酸是一种存在于绿茶中的特殊氨基酸，此前有研究表明它能增强阿霉素的抗肿瘤活性。在本研究中，我们探究了茶氨酸与阿霉素联合使用对M5076卵巢肉瘤肝转移的影响。联合治疗显著减小了M5076移植瘤（皮下接种）小鼠的原发肿瘤。由于M5076肝转移，对照小鼠的肝脏重量增加到正常水平的两倍。相比之下，单独注射阿霉素或茶氨酸加阿霉素可抑制肝脏重量增加并抑制肝转移。此外，肝脏重量和转移评分表明，茶氨酸增强了阿霉素对肝转移的抑制作用。此外，体外实验表明，茶氨酸增加了M5076细胞内阿霉素的残留浓度。这一作用表明，茶氨酸可增强阿霉素在体内对肝转移的抑制效果。因此，已证实茶氨酸不仅增加了对原发肿瘤的抗肿瘤活性，还增强了阿霉素的转移抑制效果。茶氨酸对抗肿瘤药物疗效的影响有望应用于临床癌症化疗。
