核质双向转运受体蛋白importin13在角膜缘肿瘤中的差异性表达及其意义

Differential expression of nucleus-cytoplasm transport receptor protein importin13 in limbal neoplasms

背景正常干细胞相关标志物的发现为肿瘤发生机制的研究及寻找特异性的肿瘤干细胞标志物提供了新的思路，importinl3（IPO13）是新发现的IPOB家族的成员，是该家族中惟一具有细胞核和细胞质双向转运功能的蛋白，其在眼部及角膜缘肿瘤组织中生物学特性的研究甚少。目的研究细胞核及细胞质双向转运受体蛋白IPO13在人角膜缘肿瘤中的表达，并与角膜缘干细胞标志物p63的表达进行比较，探讨两者在人角膜缘肿瘤中的表达差异及意义。方法收集正常人供体眼球角膜缘处的结膜及角膜缘组织、角膜结膜乳头状瘤（CCP）和角膜结膜上皮内上皮癌（CCIN）组织标本各6例，采用冰冻切片免疫组织化学染色法检测相应组织中IPO13、p63的表达量（A值）。采用单因素方差分析法和SNK—q检验进行统计学比较。结果IPO13主要表达于人正常眼球结膜、角膜缘上皮基底细胞的细胞核内，表达于CCP、CCIN组织上皮基底细胞和基底上层细胞的细胞核内，呈棕褐色颗粒。IPO13蛋白在正常角膜结膜、CCP、CCIN组织中的表达量（A值）分别为1687±1014、3546±1375和7635±2854，总体差异有统计学意义（F=7．23，P〈O．05），其中CCP、CCIN组织中的表达量明显高于正常角膜结膜组织，差异均有统计学意义（q=4．02、5．13，P〈0．05）；CCIN组织中的表达量明显高于CCP组织，差异有统计学意义（q=3．45，P〈O．05）。p63在正常人眼球结膜、角膜缘、CCP组织上皮基底细胞和基底上层细胞的细胞核内及CCIN组织上皮全层的细胞核内均有表达。p63在正常角膜结膜组织中、CCP、CCIN组织中的表达量分别为2110±1229、3966±2129和6650±2136，差异有统计学意义（F=6．17，P〈0．05），其中CCP、CCIN标本中阳性表达的A值均明显高于正常角膜结膜标本（q=4．33、5．01，P〈0．05），CCIN标本中阳性表达的A值明显高于CCP标本，差异有统计学意义（q=3．83，P〈0．05）。结论IPO13在角膜缘上皮增生性病变中的低分化细胞中作为标志物较p63更具特异性。与正常角膜结膜组织相比，IPO13与p63在CCP、CCIN组织中的表达逐步上调，可能在角膜结膜增生性病变中起到正性调控作用。IPO13与p63在良性与恶性角膜缘上皮增生性病变中的表达差异明显，提示IPO13与p63可能在角膜缘上皮增生性病变的异常增生与分化中起重要的调控作用。

Background The study on normal stem cell markers provides a new way of thinking of that pathogenesis of cancer research and looking for specific markers of cancer stem cells. Importin13 （ IPO13 ） is a novel nucleus-cytoplasm transport receptor protein of importin ± family, the study on the biological behavior of IPO13 in ocular tissue and limbal neoplasms is lacking. Objective This study was to investigate the differential expression of IPO13 and p63 in human benign and malignant conjunctiva-cornea neoplasms. Methods The specimens of normal donor limbal and conjunctival tissues （ 6 ） , conjunciva-cornea papilloma （CCP） （ 6 ） and conjunctiva-cornea intraepithelial neoplasia（CCIN） （6）were collected from Xiangya Hospital of Center South University. The expressions of IPO13 and p63 in the corresponding tissue were qualitatively and quantitatively detected using immunochemistry. The A values of IPO13 and p63 positive response were calculated and compared among the 3 types specimens. Results The immunohistostaining on frozen sections showed that IPO13 was expressed in nuclei of basal cells of limbal and conjunctival epithelium and the cellular nuclei of basal cells and suprabasal cells of CCP and CCIN epithelium. The A values of IPO13 positive expression were 1687 ± 1014,3546 ± 1375 and 7635 ±2854 in the normal limbal specimen, CCP and CCIN, respectively, showing a significant difference among them （ F = 7.23, P〈0. 05 ） , and the A value was higher in the CCP and CCIN than that in the normal limbal tissue （q = 4. 02,5.13, P〈0. 05 ）, and that in the CCIN was significantly elevated in comparison with CCP（ q = 3.45 ,P〈0.05 ）. p63 was expressed in nuclei of basal cells and suprabasal of limbal, conjunetival and CCP epithelium, and was expressed in nuclei of the entire CCIN epithelium. The expressions of p63 in the normal conjunctiva-cornea tissue, CCP and CCIN were 2110± 1229,3966± 2129 and 6650 ± 2136 respectively, with significant difference among the three different specimens （F = 6. 17, P 〈 0.05） ,and the A value of p63 positive expression was significantly elevated in the CCP and CCIN compared with normal limbal specimen（ q= 4.33,5.01 ,P〈0.05 ） , and that in the CCIN was significantly elevated in comparison with CCP（q=3.83,P〈0. 05）. Conclusions IPO13 is more specifical in marking the poorly differentiated cells in limbal epithelial proliferative lesions than p63. Compared with the normal limbal specimen, the expressions of IPO13 and p63 in CCP and CCIN specimens gradually upregulat,which suggests that IPO13 and p63 may play a positive regulatory role in conjunetiva-cornea proliferative lesions. The differential expression of IPO13 and p63 is predominant between benign and malignant limbal epithelial proliferative lesions, indicating that IPO13 and p63 may play an important role in regulating the abnormal proliferation and differentiation of limbal epithelial proliferative lesions.