Adrenergic receptors comprise α1-adrenergic receptors (α1A, α1B, α1D), α2-adrenergic receptors (α2A, α2B, α2C), and β-adrenergic receptors (β1, β2, β3). Previous studies have reported that different cancer cell lines may express distinct adrenergic receptor subtypes, thereby influencing the biological behaviors of tumor cells. α2-adrenergic receptors participate in the regulation of various physiological functions in the human body and have been identified as potential regulatory factors in numerous cancer cell lines. In recent years, the α2A-adrenergic receptor (ADRA2A) has been implicated as having a positive impact on both breast cancer and hepatocellular carcinoma. Here, researchers demonstrate that the expression level of ADRA2A is significantly downregulated in cervical cancer tissues and cell lines. High expression of ADRA2A is significantly associated with a favorable prognosis in patients with cervical cancer. In cervical cancer cells, the overexpression of ADRA2A significantly inhibited cell proliferation, migration, and invasion capabilities, while promoting cellular senescence and apoptosis. Conversely, the silencing of ADRA2A significantly promoted the proliferation, migration, and invasion of cervical cancer cells, while inhibiting cellular senescence and apoptosis. In cervical cancer cells, ADRA2A overexpression significantly reduced the expression levels of p-PI3K, p-AKT, and p-mTOR, whereas the silencing of ADRA2A significantly increased the expression levels of these proteins. Furthermore, the researchers confirmed that ADRA2A overexpression is capable of inhibiting the growth of xenograft tumors in vivo.
Transwell assay results demonstrated that the migration and invasion capabilities of ADRA2A-overexpressing HeLa and SiHa cells were significantly reduced, whereas those of ADRA2A-knockdown cells were significantly enhanced (Figures 1A and B). Furthermore, to further investigate the impact of ADRA2A on cell migration and invasion, the researchers performed Western blot analysis. The results indicated that the expression levels of MMP-2 and MMP-9 were significantly suppressed in ADRA2A-overexpressing HeLa and SiHa cells, while they were upregulated in ADRA2A-knockdown cells (Figure 1C). These findings confirm that ADRA2A is capable of inhibiting the migration and invasion capabilities of HeLa and SiHa cells.
Figure 1. ADRA2A inhibited the abilities of migration and invasion in HeLa and SiHa cells. (Wang W, Guo X, Dan H., 2020)