Zapata J M, Krajewska M, Krajewski S, Huang R P, Takayama S, Wang H G, Adamson E, Reed J C
The Burnham Institute, Cancer Research Center, Oncogene & Tumor Suppressor Gene Program, La Jolla, CA 92037, USA.
Breast Cancer Res Treat. 1998 Jan;47(2):129-40. doi: 10.1023/a:1005940832123.
The expression of several apoptosis-regulating genes was evaluated in 9 human breast cancer cell lines, 2 immortalized human mammary epithelial lines, 1 normal breast tissue biopsy, and 3 primary breast tumors, using a multiple antigen detection (MAD) immunoblotting method. The anti-apoptotic proteins Bcl-2, Bcl-X(L), Mcl-1, and BAG-1 were present at immunodetectable levels in 7, 10, 10, and 9 of the 11 lines. Comparing these 11 cell lines among themselves revealed that steady-state levels of Bcl-2, Bcl-X(L), Mcl-1, and BAG-1 were present at relatively higher levels in 4, 6, 5, and 5 of the lines, respectively. In contrast, the pro-apoptotic proteins Bax and Bak were detected in all 11 cell lines, and were present at relatively higher levels in 10 and 5 of the 11 lines, respectively. The Interleukin-1beta converting enzyme (ICE) homolog CPP32 (Caspase-3) was expressed in 10/11 breast cell lines. High levels of p53 protein, indicative of mutant p53, were found in 8 of the 11 lines and correlated inversely with Bax expression (p = 0.01). Bcl-2 and BAG-1 protein levels were positively correlated (p = 0.03). Immunoblot analysis of primary adenocarcinomas revealed expression of the anti-apoptotic proteins Bcl-2, Bcl-X(L), Mcl-1, and BAG-1, as well as the pro-apoptotic proteins Bax, Bak, and CPP32, in at least 2 of the 3 tumors examined. Immunohistochemical analysis was also performed for all of these proteins using 20 paraffin-embedded breast cancer biopsy specimens that all contained residual normal mammary epithelium in combination with both invasive cancer and carcinoma in situ. All of these apoptosis-regulating proteins were detected in primary breast cancers, though the percentage of immunopositive tumor cells varied widely in some cases. Comparisons of the intensity of immunostaining in normal mammary epithelium and invasive carcinoma suggested that Bcl-2 immunointensity tends to be lower in cancers than normal breast epithelium (p = 0.03), whereas CPP32 immunointensity was generally higher in invasive cancers (p < 0.0001). Taken together, the results demonstrate expression of multiple apoptosis-modulating proteins in breast cancer cell lines and primary tumors, suggesting complexity in the regulation of apoptosis in these neoplasms of mammary epithelial origin.
采用多重抗原检测（MAD）免疫印迹法，在9种人乳腺癌细胞系、2种永生化人乳腺上皮细胞系、1份正常乳腺组织活检标本以及3份原发性乳腺肿瘤中，评估了几种凋亡调节基因的表达情况。抗凋亡蛋白Bcl-2、Bcl-X(L)、Mcl-1和BAG-1在11种细胞系中的7种、10种、10种和9种中呈现可免疫检测水平。对这11种细胞系进行相互比较发现，Bcl-2、Bcl-X(L)、Mcl-1和BAG-1的稳态水平分别在4种、6种、5种和5种细胞系中相对较高。相比之下，促凋亡蛋白Bax和Bak在所有11种细胞系中均有检测到，且分别在11种细胞系中的10种和5种中相对较高。白细胞介素-1β转化酶（ICE）同源物CPP32（半胱天冬酶-3）在11种乳腺细胞系中的10种中表达。在11种细胞系中的8种中发现了高水平的p53蛋白，提示为突变型p53，且与Bax表达呈负相关（p = 0.01）。Bcl-2和BAG-1蛋白水平呈正相关（p = 0.03）。对原发性腺癌的免疫印迹分析显示，在所检测的3个肿瘤中的至少2个中，抗凋亡蛋白Bcl-2、Bcl-X(L)、Mcl-1和BAG-1以及促凋亡蛋白Bax、Bak和CPP32均有表达。还使用20份石蜡包埋的乳腺癌活检标本对所有这些蛋白进行了免疫组织化学分析，这些标本均同时包含残余的正常乳腺上皮以及浸润性癌和原位癌。所有这些凋亡调节蛋白在原发性乳腺癌中均有检测到，尽管在某些情况下免疫阳性肿瘤细胞的百分比差异很大。对正常乳腺上皮和浸润性癌中免疫染色强度的比较表明，Bcl-2免疫强度在癌组织中往往低于正常乳腺上皮（p = 0.03），而CPP32免疫强度在浸润性癌中通常较高（p < 0.0001）。综上所述，结果表明多种凋亡调节蛋白在乳腺癌细胞系和原发性肿瘤中表达，提示这些乳腺上皮源性肿瘤的凋亡调控具有复杂性。
