American Association for Cancer Research
15357163mct180088-sup-195995_3_supp_4979191_pdts49.xlsx (148.11 kB)

Supplementary Table S1 from Targeting Peroxisome Proliferator-Activated Receptor γ to Increase Estrogen-Induced Apoptosis in Estrogen-Deprived Breast Cancer Cells

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posted on 2023-04-03, 15:04 authored by Ping Fan, Balkees Abderrahman, Tina S. Chai, Smitha Yerrum, V. Craig Jordan

Validation of cell lines



Susan G. Komen for the Cure Foundation

Cancer Prevention Research Institute of Texas



Peroxisome proliferator-activated receptor γ (PPARγ) is an important transcription factor that modulates lipid metabolism and inflammation. However, it remains unclear whether PPARγ is involved in modulation of estrogen (E2)-induced inflammation, thus affecting apoptosis of E2-deprived breast cancer cells, MCF-7:5C and MCF-7:2A. Here, we demonstrated that E2 treatment suppressed the function of PPARγ in both cell lines, although the suppressive effect in MCF-7:2A cells was delayed owing to high PPARγ expression. Activation of PPARγ by a specific agonist, pioglitazone, selectively blocked the induction of TNFα expression by E2, but did not affect other adipose inflammatory genes, such as fatty acid desaturase 1 and IL6. This suppression of TNFα expression by pioglitazone was mainly mediated by transrepression of nuclear factor-κB (NF-κB) DNA-binding activity. A novel finding was that NF-κB functions as an oxidative stress inducer in MCF-7:5C cells but an antioxidant in MCF-7:2A cells. Therefore, the NF-κB inhibitor JSH-23 displayed effects equivalent to those of pioglitazone, with complete inhibition of apoptosis in MCF-7:5C cells, but it increased E2-induced apoptosis in MCF-7:2A cells. Depletion of PPARγ by siRNA or the PPARγ antagonist T0070907 accelerated E2-induced apoptosis, with activation of NF-κB–dependent TNFα and oxidative stress. For the first time, we demonstrated that PPARγ is a growth signal and has potential to modulate NF-κB activity and oxidative stress in E2-deprived breast cancer cell lines. All of these findings suggest that anti-PPARγ therapy is a novel strategy to improve the therapeutic effects of E2-induced apoptosis in E2-deprived breast cancer.

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