Kallistatin induces breast cancer cell apoptosis and autophagy by modulating Wnt signaling and microRNA synthesis
Kallistatin is an endogenous protein that regulates differential signaling pathways and biological functions. Our previous studies showed that kallistatin gene therapy inhibited angiogenesis, tumor growth and metastasis in mice, and kallistatin protein suppressed Wnt-mediated growth, migration and invasion by blocking Wnt/β-catenin signaling pathway in breast cancer cells. In this study, we show that kallistatin reduced cell viability, and increased apoptotic cell death and caspase-3 activity in MDA-MB-231 breast cancer cells. Kallistatin also induced cancer cell autophagy, as evidenced by increased LC3B levels and elevated Atg5 and Beclin-1 expression; however, co-administration of Wnt or PPARγ antagonist GW9662 abolished these effects. Moreover, kallistatin via its heparin-binding site antagonized Wnt3a-induced cancer cell proliferation and increased PPARγ expression. Kallistatin inhibited oncogenic miR-21 synthesis associated with reduced Akt phosphorylation and Bcl-2 synthesis, but increased BAX expression. Kallistatin via PKC-ERK activation reduced miR-203 levels, leading to increased expression of suppressor of cytokine signaling 3 (SOCS3), a tumor suppressor. Conversely, kallistatin stimulated expression of the tumorigenic suppressors miR-34a and p53. Kallistatin’s active site is essential for suppressing miR-21 and miR-203, and stimulating miR-34a and SOCS3 expression. This is the first study to demonstrate that kallistatin’s heparin-binding site is essential for inhibiting Wnt-mediated effects, and its active site plays a key role in regulating miR-21, miR-203, miR-34a and SOCS3 synthesis in breast cancer cells. These findings reveal novel mechanisms of kallistatin in inducing apoptosis and autophagy in breast cancer cells, thus inhibiting tumor progression by regulation of Wnt/PPARγ signaling, as well as miR-21, miR-203 and miR-34a synthesis. - Highlights: • Kallistatin reduces viability and increases apoptosis in breast cancer cells. • Kallistatin induces autophagy via suppressing Wnt signaling. • Kallistatin via its active site regulates miR-21, miR-203 and miR-34a synthesis. • Kallistatin inhibits miR-203 and increases SOCS3 levels via PKC-ERK signaling. • Novel mechanisms of kallistatin in cancer cell death and tumor development.
- OSTI ID:
- 22746404
- Journal Information:
- Experimental Cell Research, Vol. 340, Issue 2; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0014-4827
- Country of Publication:
- United States
- Language:
- English
Similar Records
PKC{eta} is a negative regulator of AKT inhibiting the IGF-I induced proliferation
PPARγ inhibits ovarian cancer cells proliferation through upregulation of miR-125b