The premalignant evolution of chemically induced mouse skin papillomas is characterized by dysplastic changes, aneuploidy, induction of gamma-glutamyl transpeptidase (GGT), and changes in the expression of keratins, especially differentiation-associated K1. This keratin, which is expressed in normal epidermis and early papillomas, is no longer present in more advanced dysplastic and aneuploid papillomas and in fully invasive carcinomas. More recently, it has been shown that K13, a keratin normally present in internal epithelia but not in epidermis, is aberrantly expressed in epidermal tumors. In the present study, the timing of expression of K13 and its correlation with other markers of premalignant evolution were investigated. Papillomas were induced by SENCAR mice by a single initiating dose of 20 nmol of 7,12-dimethylbenz[a]-anthracene (DMBA) and promotion with 12-O-tetradecanoylphorbol-13-acetate (TPA) (2 micrograms twice a week). Tumors were randomly harvested at 10, 20 and 35 weeks of promotion. K13 and K1 expression in papillomas was studied using immunoblotting and immunostaining of consecutive sections, as previously described. As expected from previous studies, the distribution of K1 in papillomas collected at 10 weeks of promotion was restricted to differentiated cells and was uniform throughout the section of the papilloma. Conversely, K13 was expressed only as small foci in 10 out of 21 papillomas (48%). Papillomas of 20 weeks were also positive for K1. Staining for K13 was positive in these papillomas with the exception of only one that was essentially negative, presenting only one small positive focus. Some of the papillomas collected at week 35 were negative for K1, but immunostaining with K13 showed uniform staining of suprabasal cells in all the papillomas studied. In all cases, immunohistochemical results were confirmed by immunoblotting with proteins extracted from 7 microns sections from each paraffin block. These results indicate that keratins K1 and K13 are coexpressed in most papillomas from 10 to 35 weeks of promotion. However, analysis of adjacent sections showed that K13 positive areas are topographically located in the K1 negative areas of the papillomas, suggesting a shift in the differentiation program from epidermal to mucosal types of keratinization. Based on these and previous studies from our laboratory, we conclude that K13 is an early marker of papillomas progression, which occurs before gross chromosomal abnormalities are present in the stem line of the tumors, and precedes dysplastic changes and the onset of GGT expression, and is probably concomitant at the individual cell level with loss of K1.

译文

化学诱导的小鼠皮肤乳头状瘤的恶性前演变的特征是发育异常改变,非整倍性,γ-谷氨酰转肽酶 (GGT) 的诱导以及角蛋白表达的变化,尤其是与分化相关的k1。这种角蛋白在正常表皮和早期乳头状瘤中表达,在更晚期的增生性和非整倍体乳头状瘤以及完全浸润性癌中不再存在。最近,已经显示K13 (通常存在于内部上皮中但不存在于表皮中的角蛋白) 在表皮肿瘤中异常表达。在本研究中,研究了K13的表达时间及其与其他恶性前进化标志物的相关性。由cencar小鼠通过单次起始剂量为20 nmol的7,12-二甲基苯并 [a]-蒽 (DMBA) 诱导乳头状瘤,并用12 O-tetradecanoylphorbol-13-acetate (TPA) (每周2次2微克) 促进。在促进10、20和35周时随机收获肿瘤。如前所述,使用连续切片的免疫印迹和免疫染色研究了乳头状瘤中K13和K1的表达。正如先前研究所预期的那样,在促进10周时收集的乳头状瘤中K1的分布仅限于分化的细胞,并且在乳头状瘤的整个切片中是均匀的。相反,K13仅在21个乳头状瘤中的10个中表达为小病灶 (48%)。20周的乳头状瘤对k1也呈阳性。在这些乳头状瘤中,K13的染色是阳性的,只有一个基本上是阴性的,只有一个小的阳性焦点。在第35周收集的某些乳头状瘤的K1阴性,但在所有研究的乳头状瘤中,K13的免疫染色显示基底肌上细胞均匀染色。在所有情况下,免疫组织化学结果均通过免疫印迹从每个石蜡块的7微米切片中提取的蛋白质来证实。这些结果表明,在大多数乳头状瘤中,角蛋白K1和K13在促进10至35周的同时表达。然而,对相邻切片的分析表明,K13阳性区域在地形上位于乳头状瘤的K1阴性区域,这表明分化程序从表皮型向粘膜型角化转移。根据我们实验室的这些和先前的研究,我们得出结论,K13是乳头状瘤进展的早期标志物,发生在肿瘤干线中出现明显染色体异常之前,并且发生在发育异常改变和GGT表达开始之前,并且可能在单个细胞水平上伴随着k1的损失。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录