吉西他滨纳米磁靶向药囊对肺鳞癌移植瘤抑制作用及癌基因Ras表达的影响

Effect of gemcitabine magnetic targeted nanocapsule on inhibition of transplanted squamous cell lung carcinoma in nude mice and RAS oncogene expression

目的研究吉西他滨纳米磁靶向药囊对肺鳞癌A2细胞株体内移植瘤的抑制作用及对癌基因Ras mRNA及Ras蛋白表达的影响。方法选择SPF级雄性裸鼠60只。取处于对数生长期的的肺鳞癌细胞株A2细胞,用含有EDTA的胰酶消化后,悬液接种于在裸鼠右股外侧制作鳞癌移植瘤模型。20 d后选取肿瘤体积约为72.5 mm3的裸鼠作为实验动物模型,并分为5组:(1)Ni Ti合金支气管支架+吉西他滨纳米磁靶向药囊组;(2)Ni Ti合金支气管支架+吉西他滨组;(3)吉西他滨纳米磁靶向药囊组;(4)吉西他滨组;(5)未干预组。Ni Ti合金支气管支架于肿瘤中手术植入,纳米磁靶向药囊或化疗药物通过尾静脉注入,其中吉西他滨纳米磁靶向药囊为本研究自行制备,吉西他滨有效剂量均按45 mg/kg给予。未干预组尾静脉注射同量的生理盐水处理。均连续给药10 d。比较各组处理后的肿瘤生长情况。利用Western Blot和RT-PCR法分别检测治疗后癌组织中Ras蛋白及Ras mRNA的相对表达水平。结果与未干预组相比,Ni Ti合金支气管支架+吉西他滨纳米磁靶向药囊组、Ni Ti支架+吉西他滨组、吉西他滨纳米磁靶向药囊组、吉西他滨组的瘤重和体积均明显减少(P<0.05,P<0.01),其抑瘤率分别为59.0%、38.0%、33.0%、28.0%。Ni Ti合金支气管支架+纳米磁靶向药囊组Ras蛋白、Ras mRNA相对表达水平最低(P均<0.01),与未干预组比较,Ni Ti合金支气管支架+化疗药物组、纳米磁靶向药囊组、化疗药物组Ras蛋白、Ras mRNA相对表达水平均有所下降(P均<0.05),但3组之间差异无统计学意义(P均>0.05)。结论纳米磁靶向药囊合并Ni Ti合金支气管支架可以显著抑制肺鳞癌A2细胞移植瘤的生长,下调癌基因Ras mRNA和Ras蛋白的表达,诱导肿瘤细胞凋亡。

Objective To study the inhibition effect of magnetic targeted nanocapsule containing gemcitabine on in vivo transplanted tumor of lung squamous carcinoma A2 cell lines and the influence on oncogenc Ras mRNA and Ras protein ex- pressions in nude mice. Methods Sixty SPF grade male nude mice were selected. Transplantation tumor model of squa- mous cell carcinoma was established by vaccinating the suspension of lung squamous cell carcinoma cell line A2 in logarith- mic growth phase after digestion with trypsin containing EDTA into right lateral femoral of nude mice. The nude mice with tumor of volume about 72.5 mm3 after 20 days were served as experiment animal models and were divided into five groups ： NiTi alloy bronchial stent ＋ gemeitabine magnetic targeted nanocapsule group, NiTi alloy bronchial stent ＋ gemcitabine group, gemcitabine magnetic targeted nanocapsule group, gemcitabine group and no intervention group. NiTi alloy stent was implanted into tumor by surgery. Targeted magnetic nanoparticles or chemotherapeutic drugs were administered by tail vein injection. Targeted gemcitabine magnetic nanoparticles were self-prepared for present study. Gemcitabine was given with the effective dose of 45 mg/kg. The mice in no intervention group was treated by tail vein injection of same amount of saline. Continuous administration was given 10 days in all group. The growth situation of tumor after treatment was compared in all group. Western Blot and reverse transcription polymerase chain reaction （RT-PCR） methods were used to respectively detect the relative expression levels of Ras protein and Ras mRNA in cancer tissues after treatment. Results Compared with no intervention group,tumor weight and volume in NiTi alloy bronchial stent ＋ gemcitabine magnetic targeted nanocapsule group, NiTi alloy bronchial stent ＋ gemcitabine group, gemcitabine magnetic targeted nanocapsule group, gemcitabine group were all significantly decreased （P 〈 0.05, P 〈 0.01 ）, and their tumor inhibitory rate were 59.0%, 38.0%, 33.0% and 28.0% ,respectively. The relative expression levels of Ras protein and Ras mRNA in cancer tissues were all the lowest in NiTi alloy bronchial stent ＋ gemcitabine magnetic targeted nanocapsule group （ all P 〈 0. O1 ） and decreased same in NiTi alloy bronchial stent ＋ gemcitabine group, gemcitabine magnetic targeted nanocapsule group, gemcitabine group compared with no intervention group （ all P 〈 O. 05 ）, while there were no significant differences in these 3 groups （ all P 〉 0.05 ）. Con- clusions The magnetic targeted nanocapsule group combined with NiTi alloy bronchial stent can significantly inhibit the growth of transplanted tumor of lung squamous carcinoma A2 cells, down-regulate the expressions of oncogene Ras mRNA and Ras protein and induce apoptosis of tumor cells.