Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Cancer Biology
Nfat5/Stat3 Interaction Mediates Synergism Of High Salt With Il-17 Towards Induction Of Vegf-A Expression In Breast Cancer Cells, Suneetha Amara, Dalal Alotaibi, Venkataswarup Tiriveedhi
Nfat5/Stat3 Interaction Mediates Synergism Of High Salt With Il-17 Towards Induction Of Vegf-A Expression In Breast Cancer Cells, Suneetha Amara, Dalal Alotaibi, Venkataswarup Tiriveedhi
Biology Faculty Research
Chronic inflammation has been considered an important player in cancer proliferation and progression. High salt (sodium chloride) levels have been considered a potent inducer of chronic inflammation. In the present study, the synergistic role of high salt with interleukin (IL)‑17 towards induction of the inflammatory and angiogenic stress factor vascular endothelial growth factor (VEGF)‑A was investigated. Stimulation of MCF-7 breast cancer cells with high salt (0.2 M NaCl) and sub‑minimal IL‑17 (1 ng/ml) enhanced the expression of VEGF-A (2.9 and 2.6-fold, respectively, P<0.05) compared with untreated cells. Furthermore, co‑treatment with both high salt and sub‑minimal IL‑17 led to a 5.9‑fold increase in VEGF‑A expression (P<0.01), thus suggesting a synergistic role of these factors. VEGF‑A promoter analysis and specific small interfering RNA knock‑down of transcription factors revealed that high salt induced VEGF‑A expression through nuclear factor of activated T‑cells (NFAT)5, while IL‑17 induced VEGF‑A expression via signal transducer and activator of transcription (STAT)3 signaling mechanisms. Treatment of normal human aortic endothelial cells with the supernatant of activated MCF‑7 cells enhanced cell migration and induced expression of migration‑specific factors, including vascular cell adhesion protein, β1 integrin and cluster of differentiation 31. These data suggest that high salt levels synergize with pro‑inflammatory IL‑17 to potentially induce cancer progression and metastasis through VEGF‑A expression. Therefore, low‑salt diet, anti‑NFAT5 and anti‑STAT3 therapies may provide novel avenues for enhanced efficiency of the current cancer therapy.
Oleanolic Acid Inhibits High Salt-Induced Exaggeration Of Warburg-Like Metabolism In Breast Cancer Cells, Suneetha Amara, Mu Zheng, Venkataswarup Tiriveedhi
Oleanolic Acid Inhibits High Salt-Induced Exaggeration Of Warburg-Like Metabolism In Breast Cancer Cells, Suneetha Amara, Mu Zheng, Venkataswarup Tiriveedhi
Biology Faculty Research
Cancer cells have a proliferative advantage by utilizing intermediates of aerobic glycolysis (Warburg effect) for their macromolecule synthesis. Although the exact causes of this Warburg effect are unclear, high osmotic stress in solid tumor microenvironment is considered one of the important factors. Oleanolic acid (OA) is known to exert anti-inflammatory and anti-cancer effect. In our current studies, using breast cancer cell lines, we determined the protective role of OA in high salt-mediated osmotic stress-induced cancer growth. Hypertonic (0.16 M NaCl) culture conditions enhanced the cancer cell growth (26 %, p < 0.05) and aerobic glycolysis as marked by increased glucose consumption (34 %, p < 0.05) and lactate production (25 %, p < 0.05) over untreated cells. This effect was associated with increased expression and activity of key rate-limiting enzymes of aerobic glycolysis, namely hexokinase, pyruvate kinase type M2, and lactate dehydrogenase A. Interestingly, this high salt-mediated enhanced expression of aerobic glycolytic enzymes was efficiently reversed by OA along with the decreased cancer cell proliferation. In cancer cells, enhanced aerobic glycolysis is associated with the decreased mitochondrial activity and mitochondrial-associated caspase activity. As expected, high salt further inhibited the mitochondrial related cytochrome oxidase and caspase-3 activity. However, OA efficiently reversed the high salt-mediated inhibition of cytochrome oxidase, caspase activity, and pro-apoptotic Bax expression, thus suggesting that OA induced mitochondrial activity and enhanced apoptosis. Taken together, our data indicate that OA efficiently reverses the enhanced Warburg-like metabolism induced by high salt-mediated osmotic stress along with potential application of OA in anti-cancer therapy.