Szent István University, Faculty of Veterinary Science, Department of Pathology and Forensic Veterinary Medicine, Budapest, Hungary.
Histol Histopathol. 2010 Jan;25(1):55-62. doi: 10.14670/HH-25.55.
The aim of the present study was to characterise the expression pattern of claudin-1, -3, -4, -5 and -7 tight junction proteins in canine normal colorectum and in the low-grade, tubulopapillary colorectal carcinoma in canines.
The biopsy samples included 10 canine normal colorectal tissues and 20 canine low grade colorectal carcinomas (CLGCCs). The canine normal colorectal mucosa was negative for claudin-1. Claudin-1 was detected as a non-diffuse intense membrane labelling of neoplastic epithelial cells in low grade colorectal cancer in canines. Fifty five per cent of all tumours showed a weak cytoplasmic pattern of staining for claudin-1 protein. The normal colorectal mucosa showed diffuse punctate positivity for claudin-3. Claudin-3 was detected as an intense lateral membrane labelling of tumour cells in CLGCCs. Claudin-4 expression in surface and crypt epithelial cells of the intact colorectal mucosa in canines was punctate. Claudin-4 molecule was detected as a lateral membrane labelling of neoplastic cells in CLGCCs. The epithelium of the CLGCCs and the low grade colorectal carcinoma were negative for claudin-5. The surface and crypt epithelial cells of the canine normal colorectal mucosa showed a diffuse lateral membranous pattern of staining for claudin-7. Claudin-7 molecule was detected as an intense membrane labelling of neoplastic cells in CLGCCs. Seventy per cent of all tumours showed weak cytoplasmic positivity for claudin-7.
Consequently, we hypothesize that claudin-1 plays a role in the progression of CLGCCs. Further functional studies are needed to clarify the biological role of the mislocalization of the claudin-1 molecule from cell membrane to the cytoplasm in CLGCCs. Lower claudin-4 expression suggests that reduced expression of claudin-4 molecule may lead to cellular disorientation, detachment and invasion of CLGCCs. Further functional studies are needed to clarify the biological role of overexpression and mislocalisation of claudin-7 in CLGCCs.
本研究旨在描述犬正常结肠组织和犬低级别管状乳头状结直肠腺癌中紧密连接蛋白 claudin-1、-3、-4、-5 和 -7 的表达模式。
活检样本包括 10 例犬正常结直肠组织和 20 例犬低级别结直肠腺癌（CLGCC）。犬正常结直肠黏膜中 claudin-1 呈阴性。claudin-1 在犬低级别结直肠腺癌中作为肿瘤上皮细胞非弥漫性强膜标记物表达。所有肿瘤的 55%表现为 claudin-1 蛋白弱的细胞质染色模式。正常结直肠黏膜中 claudin-3 呈弥漫点状阳性。claudin-3 在 CLGCC 中作为肿瘤细胞的强侧向膜标记物表达。犬完整结直肠黏膜表面和隐窝上皮细胞中 claudin-4 的表达呈点状。claudin-4 分子在 CLGCC 中作为肿瘤细胞的侧向膜标记物表达。CLGCC 和低级别结直肠腺癌的上皮细胞 claudin-5 呈阴性。犬正常结直肠黏膜的表面和隐窝上皮细胞呈 claudin-7 弥漫侧向膜染色模式。claudin-7 分子在 CLGCC 中作为肿瘤细胞的强膜标记物表达。所有肿瘤的 70%表现为 claudin-7 弱的细胞质阳性。
因此，我们假设 claudin-1 在 CLGCC 进展中发挥作用。需要进一步的功能研究来阐明 claudin-1 分子从细胞膜到细胞质的定位错误在 CLGCC 中的生物学作用。claudin-4 表达降低提示 claudin-4 分子表达减少可能导致细胞定向不良、脱落和 CLGCC 浸润。需要进一步的功能研究来阐明 claudin-7 在 CLGCC 中的过表达和定位错误的生物学作用。
