VEGF-C在淋巴管生成及乳腺癌淋巴道转移中的作用

目的： 探讨阻断VEGF-C/Flt-4调控系统对淋巴管生成和乳腺癌淋巴道转移的影响。方法： 体外培养胎牛胸导管内皮细胞，观察VEGF-C和抗Flt-4抗体对淋巴管内皮细胞增殖的影响；设计合成VEGF-C反义脱氧寡核苷酸（ASODN），体外实验观察其对VEGF-C基因表达的影响；建立乳腺癌裸鼠原位移植瘤模型并观察ASODN对肿瘤淋巴管生成及肿瘤生长转移的影响。结果： 加入前列腺癌细胞PC3(高表达VEGF-C)上清后，淋巴管内皮细胞增殖活跃；加入抗Flt-4抗体后各时段细胞计数均明显少于其它各组。体外实验RT-PCR及 Western blotting显示ASODN作用的MCF-7细胞组VEGF-C mRNA及蛋白表达均低于对照组。体内RT-PCR检测表明ASODN组移植瘤VEGF-C mRNA表达明显受抑制；5-Nase-ALPase双重酶组织化学法结果显示ASODN组移植瘤的淋巴管生成明显减少；ASODN组肿瘤生长速度较对照组缓慢，且肿瘤体积、淋巴结转移明显低于对照组。结论： VEGF-C/Flt-4调控系统与乳腺癌组织的淋巴管生成及肿瘤的淋巴道转移密切相关。阻断淋巴管内皮细胞Flt-4表达，可在一定程度上抑制肿瘤细胞诱导的淋巴管内皮细胞增殖；ASODN通过下调乳腺癌VEGF-C的表达，减少肿瘤淋巴管的生成及淋巴结转移。

Role of VEGF-C in lymphangiogenesis and lymphatic metastasis of breast cancer

AIM: To study the inhibitory effect of VEGF-C/Flt-4 system on lymphangiogenesis and lymphatic metastasis of breast cancer. METHODS: Lymphatic endothelial cells (LEC) were cultured in vitro, the effects of VEGF-C and anti-Flt-4 antibody on the proliferation of treated cells were observed. The antisense oligodeoxynucleotides (ASODN) targeting VEGF-C was designed and its effect on VEGF-C gene expression in vitro experiments was observed. The nude mice transplantation tumor model was made and the effects of VEGF-C ASODN on lymphangiogenesis and metastasis in the model were determined. RESULTS: The supernatant of cultured PC3 cells promoted LEC proliferation obviously while the cells treated with anti-Flt-4 antibody were obviously decreased whenever cell counting. The mRNA and protein expression of VEGF-C in MCF-7 cells treated with ASODN were significantly lower than that in control groups in vitro. In vivo ASODN also significantly reduced the VEGF-C mRNA expression detected by RT-PCR. The result of 5-Nase-ALPase enzyme -histochemistry showed that ASODN had obvious inhibitory effect on tumor lymphangiogenesis. Tumor growth velocity in ASODN group was much slower than that in control group. ASODN also inhibited tumor volume and lymphatic metastasis. CONCLUSION: The strong relationships between VEGF-C/Flt-4 system and lymphangiogenesis and lymphatic metastasis of breast cancer have been observed. If the expression of Flt-4 is blocked, the proliferation of LEC induced by tumor cells can be blocked in some degree. ASODN inhibits tumor lymphangiogenesis and lymphatic metastasis by down-regulating VEGF-C expressions.