Zhou C, Zhou D, Esteban J, Murai J, Siiteri P K, Wilczynski S, Chen S
Division of Immunology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
J Steroid Biochem Mol Biol. 1996 Oct;59(2):163-71. doi: 10.1016/s0960-0760(96)00100-8.
The expression of aromatase in human breast tumors has been studied by the reverse-transcription polymerase chain reaction (RT-PCR) method on 70 breast tissue specimens. An RT-PCR analysis using two oligonucleotide primers derived from the exon II of the human aromatase gene revealed that aromatase mRNA was detected in all but three tissue specimens. Furthermore, primer-directed RT-PCR was performed to determine the exon I usage in aromatase mRNA in these breast tumor specimens. The analysis has revealed that exons I.3 and PII are the two major exon Is present in aromatase mRNA isolated from breast tumors, suggesting that promoters I.3 and II are the major promoters driving aromatase expression in breast cancer and surrounding adipose stromal cells. The RT-PCR analysis also detected two products, I.3A (334 bp in length) and I.3B (222 bp in length), when it was carried out using a primer derived from exon I.3 and a reverse primer derived from exon II. The nucleotide sequences of these products have been determined and indicate that I.3A contains a region which was previously thought to be an intron. In addition, RT-PCR analyses of RNA isolated from eight pairs of breast tumor and neighboring normal tissue specimens were performed to evaluate the exon I usage and the distribution of I.3A- and I.3B-containing aromatase RNA messages in breast tumor and neighboring normal tissues. The results suggest that I.3B- and I.3A-containing messages are mainly present in breast tumor and neighboring normal tissues, respectively. Finally, the exon I/promoter usage for aromatase expression in eight cell lines (skin fibroblast, MCF-7, MDA-MB-231, T-47D, SK-BR-3, JAR, OVCAR-3, and human adipose stromal cells) was examined by primer-directed RT-PCR analyses. These studies provide a basis for further evaluation of the control mechanism of aromatase expression and estrogen biosynthesis in breast tumors.
采用逆转录聚合酶链反应（RT-PCR）方法，对70份乳腺组织标本进行研究，以检测人乳腺肿瘤中芳香化酶的表达。使用源自人芳香化酶基因外显子II的两条寡核苷酸引物进行RT-PCR分析，结果显示，除3份组织标本外，其余所有标本均检测到芳香化酶mRNA。此外，通过引物定向RT-PCR确定这些乳腺肿瘤标本中芳香化酶mRNA中外显子I的使用情况。分析表明，外显子I.3和PII是从乳腺肿瘤中分离出的芳香化酶mRNA中存在的两个主要外显子I，这表明启动子I.3和II是驱动乳腺癌及周围脂肪基质细胞中芳香化酶表达的主要启动子。当使用源自外显子I.3的引物和源自外显子II的反向引物进行RT-PCR分析时，还检测到两种产物，即长度为334 bp的I.3A和长度为222 bp的I.3B。已确定这些产物的核苷酸序列，结果表明I.3A包含一个以前被认为是内含子的区域。此外，对从8对乳腺肿瘤和相邻正常组织标本中分离的RNA进行RT-PCR分析，以评估外显子I的使用情况以及含I.3A和I.3B的芳香化酶RNA信息在乳腺肿瘤和相邻正常组织中的分布。结果表明，含I.3B和I.3A的信息分别主要存在于乳腺肿瘤和相邻正常组织中。最后，通过引物定向RT-PCR分析检测了8种细胞系（皮肤成纤维细胞、MCF-7、MDA-MB-231、T-47D、SK-BR-3、JAR、OVCAR-3和人脂肪基质细胞）中芳香化酶表达的外显子I/启动子使用情况。这些研究为进一步评估乳腺肿瘤中芳香化酶表达和雌激素生物合成的调控机制提供了依据。
