Tsuyama S, Hashimoto K, Nakamura K, Tamura H, Sasaki K, Kato H
Department of Obstetrics and Gynecology, Yamaguchi University School of Medicine, Ube, Japan.
Tumour Biol. 1991;12(1):28-34. doi: 10.1159/000217685.
Squamous-cell carcinoma antigen (SCC antigen), formerly referred to as TA-4, is closely related to the grade of differentiation. Immunohistochemical studies have demonstrated that SCC antigen is also increased in the keratinizing or large-cell nonkeratinizing type of squamous-cell carcinoma but not in the small cell type. On the other hand, the appearance rate of SCC antigen in the blood circulation is almost the same in these three types of squamous-cell carcinoma. The present study was conducted to clarify the discrepancy in the production and release of this tumor marker using a squamous-cell carcinoma cell line, SKG-IIIa. SKG-IIIa cells were treated with 10 microM 5-azacytidine, a potent hypomethylating agent, to obtain several sublines with different behavior in the production of SCC antigen, and cloned by a limiting dilution technique. One subline (B-5) released significantly greater amounts of SCC antigen into the incubation medium as compared with other sublines (A-5). In in vivo studies, groups of nude mice received subcutaneous injections of the A-5 or B-5 subline, and the serum SCC antigen levels were determined after the animals exhibited palpable tumors. The serum levels of SCC antigen were significantly higher in the animals inoculated with the B-5 cells than in those inoculated with the A-5 cells. On the other hand, flow-cytometric analysis and immunohistochemical studies using a polyclonal antibody revealed that the intracellular contents of SCC antigen were greater in the A-5 cells than in the B-5 cells. Radioautography was performed using a 125I-labeled monoclonal antibody specific against the acidic fraction of this marker, a dominant form released outside the cells, which revealed that the production of the acidic fraction was somewhat greater in the B-5 cells than in the A-5 cells. These results suggest that the production and release of SCC antigen are different phenomena in squamous-cell carcinoma and that the release of SCC antigen is likely influenced by the production of the acidic fraction.
鳞状细胞癌抗原（SCC抗原），以前称为TA - 4，与分化程度密切相关。免疫组织化学研究表明，SCC抗原在角化型或大细胞非角化型鳞状细胞癌中也会升高，但在小细胞型中则不会。另一方面，这三种类型的鳞状细胞癌中SCC抗原在血液循环中的出现率几乎相同。本研究使用鳞状细胞癌细胞系SKG - IIIa来阐明这种肿瘤标志物在产生和释放方面的差异。用10微摩尔的5 - 氮杂胞苷（一种有效的去甲基化剂）处理SKG - IIIa细胞，以获得在SCC抗原产生方面具有不同行为的几个亚系，并通过有限稀释技术进行克隆。与其他亚系（A - 5）相比，一个亚系（B - 5）向培养介质中释放的SCC抗原量显著更多。在体内研究中，将裸鼠分组皮下注射A - 5或B - 5亚系，在动物出现可触及的肿瘤后测定血清SCC抗原水平。接种B - 5细胞的动物血清中SCC抗原水平显著高于接种A - 5细胞的动物。另一方面，使用多克隆抗体的流式细胞术分析和免疫组织化学研究表明，A - 5细胞中SCC抗原的细胞内含量高于B - 5细胞。使用针对该标志物酸性部分（细胞外释放的主要形式）的125I标记单克隆抗体进行放射自显影，结果显示B - 5细胞中酸性部分的产生比A - 5细胞略多。这些结果表明，SCC抗原的产生和释放是鳞状细胞癌中的不同现象，并且SCC抗原的释放可能受酸性部分产生的影响。
