Song Chang-Cheng, Lu Xiang, Cheng Bin-Bin, DU Juan, Li Bai, Ling Chang-Quan
Department of Traditional Chinese Medicine, Changhai Hospital, Second Militaty Medical University, Shanghai, 200433, PR China.
Ai Zheng. 2007 Dec;26(12):1315-22.
BACKGROUND & OBJECTIVE: Melittin has antitumor effects on osteosarcoma, leukemia, and cervical cancer in vitro. Our previous experiments showed that melittin could inhibit proliferation and induce apoptosis of human hepatocellular carcinoma BEL-7402 cells. This study was to examine the effects of melittin on the growth and angiogenesis of BEL-7402 cell xenografts in nude mice.
The xenografts derived from BEL-7402 cells were established in BALB/C nude mice. Inoculated mice were randomly divided into normal saline (NS, 10 ml/kg) group, positive control (thalidomide, TLD, 200 mg/kg) group, low dose melittin (40 microg/kg) group, moderate dose melittin (60 microg/kg) group and high dose melittin (80 microg/kg) group. Tumor volume was measured. Tumor tissue was observed under microscope. Microvessel density (MVD) and the expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and nuclear factor kappaB (NF-kappaB) were detected by SABC immunohistochemistry. The mRNA levels of VEGF and bFGF were analyzed by real-time fluorescent quantitative polymerase chain reaction.
The relative tumor volume (V/V0) and MVD were significantly lower in low, moderate and high dose melittin groups than in NS group (4.42+/-0.58, 3.47+/-0.97, and 3.06+/-1.23 vs. 9.06+/-1.45, P<0.01; 11.33+/-1.86, 9.17+/-1.17, and 6.67+/-1.21 vs. 16.50+/-2.35, P<0.01). Tumor tissue necrosis was observed in melittin-treated groups and tumor vessels were destroyed by melittin. The positive expression indexes of VEGF (2.59+/-0.27, 2.61+/-0.17, 1.55+/-0.22 vs. 3.80+/-0.60, P<0.01), bFGF (2.45+/-0.78, 2.27+/-0.36, 2.10+/-0.27 vs. 4.43+/-0.34, P<0.01) and NF-kappaB (2.79+/-0.29, 2.71+/-0.66, 2.26+/-0.56 vs. 4.98+/-0.63, P<0.01) were significantly lower in low, moderate and high dose melittin groups than in NS group. The mRNA levels of VEGF and bFGF were also significantly lower in melittin-treated groups than in NS group.
Melittin could inhibit the growth of BEL-7402 cell xenografts in nude mice. The down-regulation of VEGF, b-FGF and NF-kappaB expression and the inhibition of angiogenesis might play key roles in the antitumor effect of melittin.
蜂毒肽在体外对骨肉瘤、白血病和宫颈癌具有抗肿瘤作用。我们之前的实验表明，蜂毒肽可抑制人肝癌BEL - 7402细胞的增殖并诱导其凋亡。本研究旨在探讨蜂毒肽对BEL - 7402细胞裸鼠异种移植瘤生长和血管生成的影响。
将BEL - 7402细胞来源的异种移植瘤接种于BALB/C裸鼠。接种后的小鼠随机分为生理盐水（NS，10 ml/kg）组、阳性对照（沙利度胺，TLD，200 mg/kg）组、低剂量蜂毒肽（40 μg/kg）组、中剂量蜂毒肽（60 μg/kg）组和高剂量蜂毒肽（80 μg/kg）组。测量肿瘤体积。在显微镜下观察肿瘤组织。采用SABC免疫组织化学法检测微血管密度（MVD）以及血管内皮生长因子（VEGF）、碱性成纤维细胞生长因子（bFGF）和核因子κB（NF - κB）的表达。通过实时荧光定量聚合酶链反应分析VEGF和bFGF的mRNA水平。
低、中、高剂量蜂毒肽组的相对肿瘤体积（V/V0）和MVD均显著低于NS组（4.42±0.58、3.47±0.97和3.06±1.23比9.06±1.45，P<0.01；11.33±1.86、9.17±1.17和6.67±1.21比16.50±2.35，P<0.01）。在蜂毒肽处理组中观察到肿瘤组织坏死，且蜂毒肽破坏了肿瘤血管。低、中、高剂量蜂毒肽组的VEGF（2.59±0.27、2.61±0.17、1.55±0.22比3.80±0.60，P<0.01）、bFGF（2.45±0.78、2.27±0.36、2.10±0.27比4.43±0.34，P<0.01）和NF - κB（2.79±0.29、2.71±0.66、2.26±0.56比4.98±0.63，P<0.01）阳性表达指数均显著低于NS组。蜂毒肽处理组的VEGF和bFGF的mRNA水平也显著低于NS组。
蜂毒肽可抑制BEL - 7402细胞裸鼠异种移植瘤的生长。VEGF、b - FGF和NF - κB表达的下调以及血管生成的抑制可能在蜂毒肽的抗肿瘤作用中起关键作用。
