The Role of Calcineurin/NFAT in SFRP2 Induced Angiogenesis—A Rationale for Breast Cancer Treatment with the Calcineurin Inhibitor Tacrolimus

Abstract

Tacrolimus (FK506) is an immunosuppressive drug that binds to the immunophilin FKBPB12. The FK506-FKBP12 complex associates with calcineurin and inhibits its phosphatase activity, resulting in inhibition of nuclear translocation of nuclear factor of activated T-cells (NFAT). There is increasing data supporting a critical role of NFAT in mediating angiogenic responses stimulated by both vascular endothelial growth factor (VEGF) and a novel angiogenesis factor, secreted frizzled-related protein 2 (SFRP2). Since both VEGF and SFRP2 are expressed in breast carcinomas, we hypothesized that tacrolimus would inhibit breast carcinoma growth. Using IHC (IHC) with antibodies to FKBP12 on breast carcinomas we found that FKBP12 localizes to breast tumor vasculature. Treatment of MMTV-neu transgenic mice with tacrolimus (3 mg/kg i.p. daily) (n = 19) resulted in a 73% reduction in the growth rate for tacrolimus treated mice compared to control (n = 15), p = 0.003; which was associated with an 82% reduction in tumor microvascular density (p<0.001) by IHC. Tacrolimus (1 µM) inhibited SFRP2 induced endothelial tube formation by 71% (p = 0.005) and inhibited VEGF induced endothelial tube formation by 67% (p = 0.004). To show that NFATc3 is required for SFRP2 stimulated angiogenesis, NFATc3 was silenced with shRNA in endothelial cells. Sham transfected cells responded to SFRP2 stimulation in a tube formation assay with an increase in the number of branch points (p<0.003), however, cells transfected with shRNA to NFATc3 showed no increase in tube formation in response to SFRP2. This demonstrates that NFATc3 is required for SFRP2 induced tube formation, and tacrolimus inhibits angiogenesis in vitro and breast carcinoma growth in vivo. This provides a rationale for examining the therapeutic potential of tacrolimus at inhibiting breast carcinoma growth in humans.

Nuclear factor of activated T cells in cancer development and treatment

“…Several soluble factors have been identified to correlate with tumor angiogenesis, including vascular endothelial growth factor A (VEGFA), acidic/basic fibroblast growth factor (a-FGF/b-FGF) and secreted frizzle-related protein 2 (SFRP2) [11,87,88]. VEGFA activates PLCγ by binding to the VEGF receptor (VEGFR), while FGF23 binds to FGF receptor 1c (FGFR1c).…”

miR-338-5p Regulates the Viability, Proliferation, Apoptosis and Migration of Rheumatoid Arthritis Fibroblast-Like Synoviocytes by Targeting NFAT5

“…Several reports conveyed the information that NFAT5 could help sustain intracellular homeostasis which is critical for natural cell proliferation [37,38]. Accumulating evidence suggests that NFAT-5 is attached to cytoskeleton and activate downstream effectors like Cox-2 to facilitate cancer cell metastasis [39]. In addition, NFAT signaling in the tumor microenvironment is likely to have a significant impact on chemokine signaling [40].…”

Updated Landscape of the Tumor Microenvironment and Targeting Strategies in an Era of Precision Medicine

“…Expression of the secreted frizzled-related protein 2 (SFRP2), a typical modulator of Wnt signaling, is increased in the stroma damaged by the chemotherapeutic cycles [56]. Beyond holding the potential to promote angiogenesis via the calcineurin/NFAT signaling in a noncanonical Wnt pathway [71,72], SFRP2 can interact directly with WNT16B to enhance its canonical activities, eventually generating a substantially strengthened malignant phenotype including remarkable drug resistance in prostate cancer [73]. Data from targeting angiopoietins (Ang1, Ang2, Ang4) which cause CAF accumulation and neoangiogenesis in the TME, and TEK (referring to Tie1/Tie2) receptors responsible for the maturation and plasticity of blood vessels, are recently reported [74,75].…”