Telmisartan inhibits NSCLC A549 cell proliferation and migration by regulating the PI3K/AKT signaling pathway

Abstract

Expression of angiotensin II (Ang II), a key biological peptide in the renin-angiotensin system, is closely associated with the occurrence and development of cancer. Ang II binds two receptor subtypes, the Ang II type 1 receptor (AT1R) and the AT2R, to mediate a series of biological effects. Telmisartan, a specific AT1R blocker, has been reported to have potential as an anticancer drug for treating renal cancer. In the present study, whether telmisartan had an effect on non-small cell lung cancer (NSCLC) cell proliferation and migration was investigated. The Cell Counting kit-8 assay revealed that telmisartan significantly inhibited the growth of the NSCLC A549 cell line in a time- and dose-dependent manner. In a transwell assay, telmisartan significantly inhibited cellular invasion and migration. Furthermore, it was determined that the expression of the anti-apoptotic protein B-cell lymphoma was decreased, and that of the pro-apoptotic proteins caspase-3 and Bcl-associated X increased in the A549 cells treated with telmisartan. Additionally, levels of phosphorylated RAC serine/threonine-protein kinase (p-AKT), p-mechanistic target of rapamycin, p70-S6 kinase and cyclin D1 was decreased in the telmisartan-treated group. Therefore, the current study reveals that telmisartan-induced NSCLC apoptosis may be regulated via the phosphoinositide 3-kinase/AKT signaling pathway, which indicates that it may be a potential novel drug for clinical NSCLC treatment.

Keywords: angiotensin II; angiotensin II receptor blockers; angiotensin II type 1 receptor; non-small cell lung cancer; phosphoinositide 3-kinase/RAC serine/threonine protein kinase; telmisartan.

Figure 1.

Telmisartan inhibited A549 cell proliferation using the Cell Counting Kit-8 assay. *P<0.05, compared with the vehicle group; ^#P<0.05, compared with NC group. OD, optical density; DMEM, Dulbecco's modified Eagle's medium; DMSO, dimethyl sulfoxide; NC, negative control.

Figure 2.

Telmisartan inhibits A549 cell invasion and migration. (A) Images are representative of crystal violet-stained A549 invaded cells. (B) Images representative of crystal violet-stained A549 migrated cells. Images were captured using an inverted microscope at a magnification of ×100. NC, negative control.

Figure 3.

Telmisartan induces A549 cell apoptosis. (A) A549 cells were treated with 20 µM telmisartan for 24 h and labeled with Annexin V-FITC and PI, followed via flow cytometric analysis. (B) Western blot analysis of A549 cells treated with telmisartan for 24 h. The band intensities were quantified. The results were normalized to the GAPDH loading control. (C-E) Relative levels of the indicated apoptosis-associated proteins. *P<0.05, compared with NC group. NC, negative control; PI, propidium iodide; FITC, fluorescein isothiocyanate.

Figure 4.

Effects of telmisartan on the PI3K signaling pathway in A549 cells. (A) Expression levels of AKT, p-AKT, mTOR, p-mTOR, p70S6K and cyclin D1 were measured in A549 cells treated with 20 µM telmisartan by western blot analysis. (B-G) The relative protein levels of AKT, p-AKT, mTOR, p-mTOR, p70S6K and cyclin D1 compared with the control group. *P<0.05, compared with NC group. PI3K, phosphoinositide 3-kinase; p-AKT, phosphorylated RAC serine/threonine-protein kinase; mTOR, mechanistic target of rapamycin; p70S6K, p70-S6 kinase; NC, negative control.