ANG-1, ANG-2 and VEGF levels in co-culture media and mRNA expression were upregulated and Tie2 mRNA expression was downregulated in the HUVECs and MCF-7.
We previously discovered an anti-angiogenic miR-542-3p, which directly targeted the key angiogenesis-promoting protein Angiopoietin-2 to inhibit tumor angiogenesis in breast cancer models.
Moreover, MDA-MB-231/HMEC-1 co-cultures produced significantly increased levels of ANG2 (up to 580 pg/ml) and VEGF protein (up to 38,400 pg/ml) while ANG1 protein expression was decreased relative to MDA-MB-231 monocultures.
Since increased expression of Ang2 correlates with elevated potential of human breast cancer metastasis in clinic, our data underscore the importance that up-regulated Ang2 not only stimulates breast cancer growth and metastasis at late stages of the process, but is also critical at the initiating stages of metastases onset, thereby suggesting Ang2 as a promising therapeutic target for treating patients with metastatic breast cancer.
These studies provide evidence that the Ang-2 gene is regulated by HER2 activity in breast cancer, and propose an additional mechanism for HER2 contributing to tumor angiogenesis and metastasis.
Here we demonstrated, by RT-PCR analysis, the expression of both angiotensin II (Ang II) receptor subtypes, AT1 and AT2, in a breast cancer epithelial cell line, MCF-7.
We tested human breast cancers and breast cancer cell lines for coexpression of HER2 and Ang-2 with Northern blot, reverse transcriptase-polymerase chain reaction, and enzyme-linked immunosorbent assay.