Expression of A2A and A2B Adenosine Receptors in Human Breast Tumors

The expression profile, signal transduction, molecular function and cell growth modulation of adenosine receptor subtypes in the human breast cancer cell lines are described; we decided to investigate the possible roles of adenosine receptors in the human breast tissues. In this study, we used Real-Time (RT) PCR to assess A2A and A2B gene expression in normal and tumoral breast tissues. Breast tumors and non-neoplastic mammary tissues (n = 15) were collected immediately after mastectomy and stored at -80°C until use. All tumors were histologically confirmed to be breast cancer. Total RNA was extracted and reverse transcribed to cDNA. PCR primers were synthesized from human adenosine receptor cDNA sequences. PCR was performed under optimized condition for each receptor subtype. Amplification of beta-actin mRNA served as control for RT-PCR. The PCR products were separated on 1.5% agarose gels. To elucidate the expression of A2A and A2B mRNA in breast carcinoma and normal tissues, we compared the level of A2A and A2B mRNA expression by RT-PCR analysis. All breast tumor and normal tissue specimens expressed A2A and A2B adenosine receptor transcripts. We observed that expression of A2B in tumor tissues is 1.36 fold of normal tissues but there was no difference between the expressions of A2A in tumor and normal tissues of the breast, when normalized against that of beta-actin. These results indicated for the first time, to our knowledge, the expression profile of A2A and A2B adenosine receptors in the human breast carcinoma. The present study showed that a high A2B gene expression level was found in breast tumor tissues in comparison with the normal tissues. However, further studies based on the Real-time quantitative RT-PCR are needed to confirm gene expression levels.