目的：探讨维生素C（VitC）对乳腺癌细胞紫杉醇（PTX）化疗的增敏作用及机制。方法：分别将VitC与PTX单独或联合作用原代培养的人乳腺癌细胞后，用MTS法、流式细胞仪、Western blot检测细胞的增殖、凋亡以及caspase-3与Bcl-2的表达。结果：单独用药时，VitC对乳腺癌细胞的IC50为2.5 mmol/L，PTX为8.6 nmol/L，但联合1 mmol/L的VitC后，PTX对乳腺癌细胞的IC50为2.8 nmol/L；VitC单用有一定的促乳腺癌细胞凋亡作用，PTX与VitC联用后的促乳腺癌细胞凋亡作用明显大于PTX单用，且随着VitC浓度的增加而增强（均P<0.05）；PTX单独作用后，乳腺癌细胞caspase-3的表达上调，Bcl-2的表达下调，联合VitC后该作用更加明显，且随VitC浓度的增加而增加（均P<0.05）。结论：VitC可提高乳腺癌细胞PTX化疗的敏感性，该作用可能与其进一步提高caspase-3、降低Bcl-2的表达有关。
Effect of Vitamin C on sensitivity of breast cancer cells to paclitaxel chemotherapy
Objective: To investigate to the effect of vitamin C (VitC) on enhancing the sensitivity of breast cancer cells to paclitaxel (PTX) chemotherapy and the mechanism. Methods: In primary cultured human breast cancer cells after exposure to VitC alone or PTX alone or their combination, the proliferation, apoptosis and expressions of caspase-3 and Bcl-2MTS were determined by MTS assay, flow cytometry and Western blot analysis, respectively. Results: In breast cancer cells, the IC50 of VitC alone was 2.5 mmol/L and PTX alone was 8.6 nmol/L, while IC50 of PTX combined with 1 mmol/L VitC was 2.8 nmol/L. VitC alone had certain apoptosis inducing effect on breast cancer cells, and the apoptosis inducing effect of PTX combined with VitC was significantly greater than that of PTX alone, which was also increased with increase of the concentration of VitC (all P<0.05). The caspase-3 expression was increased and Bcl-2 expression was decreased significantly after exposure of PTX alone, and these effects were enhanced by combination with VitC, and increased with the increase of the concentration of VitC added (all P<0.05). Conclusion: VitC can enhance the sensitivity of breast cancer cells to PTX chemotherapy, and this action may be related to its further increase caspase-3 and decrease Bcl-2 expressions.