反义VEGF165基因转染对人神经母细胞瘤生物学行为的影响

目的探讨反义VEGF165基因转染在抑制肿瘤血管生成和肿瘤生长中的作用。方法构建正义和反义VEGF165真核表达载体,用脂质体转染人神经母细胞瘤细胞SH-SY5Y,G418筛选稳定表达细胞克隆。应用RT-PCR证实外源性反义VEGF mRNA的表达,免疫细胞化学和EUSA检测VEGF蛋白的表达水平,MTT法检测肿瘤细胞体外生长情况,并接种于裸鼠皮下,观察体内肿瘤增殖能力。结果RT-PCR证实转染反义VEGF的细胞中有外源性反义VEGF mRNA的表达,免疫细胞化学和EUSA显示VEGF蛋白表达明显降低,MTT实验显示转染前后细胞体外生长速度基本一致。而转染反义VEGF的肿瘤细胞裸鼠体内生长速度明显减慢。结论反义VEGF基因转染能够有效抑制SH-SY5Y细胞内源性VEGF蛋白的表达,抑制裸鼠体内肿瘤的生长。     

p53 OVEREXPRESSION AND HUMAN PAPILLOMAVIRUS INFECTION IN TRANSITIONAL CELL CARCINOMA OF THE URINARY BLADDER: CORRELATION WITH HISTOLOGICAL PARAMETERS

Seventy-nine transitional cell carcinomas (TCCs) of the urinary bladder (25 grade 1, 22 grade 2, and 32 grade 3 tumours) were examined for p53 overexpression by immunohistochemistry with a monoclonal antibody and for human papillomavirus (HPV) infection by the polymerase chain reaction (PCR). Positive immunostaining for p53 was detected in 40·5 per cent of the cases; the percentage of positive cases was significantly lower in low-grade (G1 and G2) TCCs than in high-grade (G3) tumours (10·6 per cent vs. 84·4 per cent; P <0·0001). The overall rate of HPV infection was 32·9 per cent; 20·3 per cent of the cases were positive for HPV 16, 3·8 per cent for HPV 18, and 8·9 per cent for both. Consensus primers as well as type-specific primers for HPV types 6, 11, and 33 failed to detect any additional case with HPV infection. The prevalence of HPV 16 and/or HPV 18 infection was significantly higher in low-grade than in high-grade tumours (44·7 per cent vs. 15·6 per cent; P =0·0061). p53-positive cases were more common among papillary, deeply infiltrating tumours, and HPV-positive cases among papillary, non-infiltrating lesions. According to these data, p53 overexpression and HPV 16/18 infection are common findings in bladder TCC and there appears to be an inverse correlation of p53 overexpression and of HPV infection with tumour aggressiveness. The possibility of different molecular pathways in superficial low-grade and in invasive high-grade tumours is suggested.     

人鼻咽癌CNE－2Z细胞的不同转移潜能克隆株在严重联合免疫缺陷小鼠体内的检验和比较研究

将人类鼻咽癌不同克隆株的细胞悬液移植在严重联合免疫缺陷（ＳＣＩＤ）小鼠和ＢＡＬＢ／ｃ（ｕｎ／ｕｎ）裸小鼠的颈背侧皮下，５６ｄ后处死全部动物进行观察。结果发现，在ＳＣＩＤ小鼠体内移植后ＣＮＥ２Ｌ２为高转移克隆株，其淋巴结转移率为１００％，肺转移率为７１％；而ＣＮＥ２Ｌ４为低转移克隆株，其肺转移率为１３％，淋巴结未见癌转移。这是从１个细胞母系中新筛选出的１个高转移和１个低转移的癌细胞克隆株。实验结果还显示，同ＢＡＬＢ／ｃ（ｕｎ／ｕｎ）裸小鼠相比，ＳＣＩＤ小鼠的恶性表型的表达能力高。另外，皮下移植时肿瘤细胞的数量可能与转移表型的表达有相关性，移植的瘤细胞数越多，转移率越高，反之亦然。     

二乙基己烯雌酚诱发成年仓鼠睾丸生精异常及对生精细胞表达bcl-2、P53和cadherin的影响

目的探讨在二乙基己烯雌酚(DES)诱发成年动物生精异常过程中,原癌基因bcl-2、p53及黏附分子cadherin在生精细胞中表达的变化,旨在阐明DES诱发生精异常的作用机理。方法成年雄性仓鼠皮下注射DES连续7d后,取其睾丸,进行光镜及电镜的观察和原癌基因bcl-2、p53及黏附分子cadherin的免疫组织化学染色。结果DES处理组的成年仓鼠睾丸生精细胞发育异常,bcl-2和p53表达量均比对照组有显著增加,并以精母细胞和圆形精子细胞较为明显。生精上皮中cadherin的表达比对照组有明显减少。结论DES增加精母细胞和圆形精子细胞表达bcl-2和p53;同时抑制cadherin表达,是诱发成年仓鼠生精异常的原因之一。     

转化生长因子β-1联合内脏内胚层样END-2细胞共培养对小鼠胚胎干细胞体外分化为心肌细胞的实验研究

目的添加转化生长因子_1β(TGF_β1)以及与内脏内胚层样END_2细胞共培养,定向诱导胚胎干细胞(ESCs)分化,探索联合使用化学诱导法与共培养法对ESCs的心肌细胞定向诱导分化作用。方法将ESCs悬浮培养形成2~3 d类胚体(EBs),再向培养液内添加TGF_β1,或(和)将2~3 d EBs与END_2细胞或END_2细胞条件培养液共培养。自然分化为对照组。免疫荧光技术检测心肌细胞特异性肌动蛋白(α_actin)及肌钙蛋白T(TnT)的表达,透射电镜观察分化心肌细胞的超微结构。结果向培养液添加TGF_β1或将2~3 d EBs与END_2细胞或END_2细胞条件培养液共培养,各自有(43±2.08)%(P<0.01),(69±3.61)%(P<0.01),(65±3.06)%(P<0.01)的EBs出现自发节律性收缩,均表达心肌细胞特异性蛋白α_Actin和TnT,观察到心肌样超微结构。自然分化组发生自发节律性收缩的EBs只有(12±1.53)%,尤其是联合使用两种诱导方法,自发性收缩的EBs高达(91±1.52)%(P<0.01),收缩区域较单一诱导组大,且细胞形态较单一。结论联合使用化学诱导和共培养2种诱导法对ESCs的心肌细胞定向分化有协同作用。