含5-氟尿嘧啶稀土磷钨酸盐诱导细胞凋亡作用研究

 多金属氧酸盐作为一种无机金属-氧簇化合物，在抗肿瘤、抗病毒等药物化学领域引起广泛关注。研究了以下5种含5-氟尿嘧啶稀土磷钨酸盐K₉（C₄H₄FN₂O₂）₂La（PW₁₁O₃₉）₂·18H₂O，K₉（C₄H₄FN₂O₂）₂Ce（PW₁₁O₃₉）₂·23H₂O，K₉（C₄H₄FN₂O₂）₂Nd（PW₁₁O₃₉）₂·25H₂O，K₉（C₄H₄FN₂O₂）₂Sm（PW₁₁O₃₉）₂·11H₂O和K₉H（C₄H₄FN₂O₂）Eu（PW₁₁O₃₉）₂·11H₂O（FLnPW，Ln=La、Ce、Nd、Sm、Eu）对HeLa细胞凋亡和周期的影响，以5-氟尿嘧啶为阴性对照，同时比较了含5-氟尿嘧啶磷钨酸盐K11C₄H₄FN₂O₂（PW₁₁O₃₉）·7H₂O（FPW）及磷钨酸H₃PW₁₂O₄₀（PW）的生物活性。细胞形态检测表明，化合物作用于HeLa细胞后均出现明显凋亡形态特征，细胞核染色质呈高度浓缩和边缘化现象（PW除外）。流式细胞周期检测表明，化合物作用后HeLa细胞均出现S期阻滞，与5-氟尿嘧啶相比，FPW作用后S期阻滞增强，而FCePW、FNdPW和FEuPW组同时出现S期和G₂/M期阻滞。流式细胞检测表明，化合物诱导HeLa细胞发生凋亡（PW除外），且诱导凋亡活性顺序为FLnPW > FPW > 5-氟尿嘧啶。Caspase 3检测表明，化合物作用后Caspase 3活性增强（PW除外），活性顺序与凋亡活性顺序相同，其中FCePW组和FEuPW组Caspase 3相对活性显著增强。实验结果表明，所考查化合物（PW除外）能诱导细胞周期阻滞、诱导凋亡活性以及激活Caspase 3，且FLnPW的活性均高于FPW和5-氟尿嘧啶，而PW只能使肿瘤细胞发生坏死，说明5-氟尿嘧啶和稀土元素对化合物的抗肿瘤活性发挥关键作用，FLnPW可能是通过诱导细胞周期阻滞以及激活Cas-pase 3细胞凋亡通路，实现显著抑制HeLa细胞增殖。

Apoptosis-inducing effects of rare earth substituted phosphotungstic acid containing 5-fluorouracil on HeLa cells

As a kind of inorganic metal-oxide cluster compound, polyoxometalates' potential antitumor activities have gained much attention. In this paper, the bioactivities of a series of rare earth substituted phosphotungstic acids containing 5-fluorouracil, K₉(C₄H₄FN₂O₂)₂La(PW₁₁O₃₉)₂·18H₂O, K₉(C₄H₄FN₂O₂)₂Ce(PW₁₁O₃₉)₂·23H₂O, K₉(C₄H₄FN₂O₂)₂Nd(PW₁₁O₃₉)₂·25H₂O, K₉(C₄H₄FN₂O₂)₂Sm(PW₁₁O₃₉)₂·11H₂O and K₉H(C₄H₄FN₂O₂)Eu(PW₁₁O₃₉)₂·11H₂O (abbr. FLnPW, Ln=La, Ce, Nd, Sm, Eu) on HeLa cell are investigated. 5-fluorouracil (abbr. 5-FU) is used as positive control, and phosphotungstate containing 5-fluroracil K11C₄H₄FN₂O₂(PW₁₁O₃₉)·7H₂O (abbr. FPW) and phosphotungstic acid H₃PW₁₂O₄₀ (abbr. PW) are also tested. Morphological analysis shows that typical characteristics of apoptosis appear after treatment with the above compounds (besides PW), and nuclear chromatin is highly concentrated and marginalized. Flow cytometry indicates that S phase cell cycle arrest is induced by compounds (besides PW), whose FPW shows higher S-phase arrest activity than 5-FU, and that the FCePW, FNdPW and FEuPW groups show S phase and G₂/M phase arrests simultaneously. Flow cytometry also shows that all compounds except PW induce apoptosis in HeLa cells, and that the apoptosis-inducing activity order is FLnPW > FPW > 5-FU. Caspase 3 detection shows that caspase 3 activity of HeLa cell is enhanced after treatment with compounds, and the caspase 3 activity order is FLnPW>FPW>5-FU, where the FCePW and FEuPW groups show significant higher activities. These results show that the above compounds containing 5-FU group possess cell cycle arrest activity, apoptosis-inducing activity and caspase 3 inducing activity, while PW could only cause cell death because of acidity. It is suggested that 5-FU group and rare earth elements play most important roles in the antitumor activity, and FLnPW could inhibit cell proliferation by inducing cell cycle arrest, activating the caspase 3-dependent apoptosis pathway.