Expression of ras oncogene mRNA and protein in aberrant crypt foci.
Expression of ras oncogene mRNA and protein in aberrant crypt foci.
复制标题
异常隐窝病灶中 ras 癌基因 mRNA 和蛋白的表达。
作者：
S. Stopera;R. Bird
通过原位杂交和免疫组织化学方法研究了异常隐窝病灶中ras癌基因的表达。假设异常隐窝病灶代表啮齿动物结肠中最早可识别的结肠癌微观病变。 Sprague-Dawley雄性大鼠皮下注射氧化偶氮甲烷(20mg/kg)一次。十二周后，通过地形学鉴定异常的隐窝病灶，进行显微解剖并进行组织学处理。与 c-ras 反义寡聚物的原位杂交表明，与正常隐窝相比，异常隐窝中 ras 特异性 RNA 的表达增加。与相应的有义寡聚物获得少量的非特异性杂交。计算早期和晚期异常隐窝病灶中带有颗粒的细胞百分比（标记指数）。该指数也在正常出现的隐窝中计算。早期和晚期异常隐窝病灶的标记指数显着高于正常隐窝病灶的标记指数（18.0 和 25.0 vs 11.9）。在相同的组织标本中，使用单克隆抗体 (Y13-259) 对 ras p21 进行免疫组织化学染色显示，与正常隐窝 (3/50) 相比，早期异常隐窝 (15/22) 和晚期异常隐窝 (22/30) 的染色强度较强。免疫组织化学结果表明，同一组织中 ras p21 水平升高，同时 ras 特异性信息水平升高。这项研究首次证明了具有发育不良特征的结肠癌前驱病变中 ras 癌基因表达增加。
The expression of the ras oncogene in aberrant crypt foci was studied by both in situ hybridization and immunohistochemical approaches. Aberrant crypt foci are hypothesized to represent the earliest identifiable microscopic lesions of colon cancer in rodent colons. Sprague-Dawley male rats were injected with azoxymethane (20 mg/kg s.c.) once. Twelve weeks later, aberrant crypt foci were identified topographically, microdissected and processed for histology. In situ hybridization with an antisense oligomer of c-ras demonstrated increased expression of ras-specific RNA in aberrant crypts compared to normal crypts. A low amount of non-specific hybridization was obtained with the corresponding sense oligomer. The percentage of cells with grains (labeling index) was calculated in early and advanced aberrant crypt foci. This index was also calculated in normal appearing crypts. The labeling indices for the early and advanced aberrant crypt foci were significantly greater than that of normal crypts (18.0 and 25.0 versus 11.9). In the same tissue specimens, immunohistochemical staining for ras p21 with the monoclonal antibody (Y13-259) revealed strong staining intensity in early aberrant crypts (15/22) and advanced aberrant crypts (22/30) compared to normal crypts (3/50). The immunohistochemical results demonstrate the presence of elevated levels of ras p21 in the same tissue as increased levels of ras-specific message. This investigation provides the earliest demonstration of increased expression of the ras oncogene in precursor lesions of colon cancer possessing dysplastic features.