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The role of calcineurin/NFAT in SFRP2 induced angiogenesis--a rationale for breast cancer treatment with the calcineurin inhibitor tacrolimus.

Siamakpour-Reihani S, Caster J, Bandhu Nepal D, Courtwright A, Hilliard E, Usary J, Ketelsen D, Darr D, Shen XJ, Patterson C, Klauber-Demore N - PLoS ONE (2011)

Bottom Line: 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).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.

View Article: PubMed Central - PubMed

Affiliation: Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America.

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.

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Tacrolimus reduces tumor vascularity.MMTVneu tumors from 4 control 20% intralipid mice and 4 tacrolimus treated mice were resected and embedded in paraffin. Immunohistochemistry with antibody to factor VIII was performed as described in “Material and Methods”. Microvessel density was determined by counting the number of microvessels in 3 high-power fields at 200×. A, D) The mean number of microvessels per high power field in control tumors was 104±13. B, D) The mean number of microvessels per high power field in tacrolimus treated tumors was 20±1 (p<0.001). This shows that tacrolimus reduces angiogenesis in vivo. C) Negative control human breast tumor without primary antibody shows no staining.
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pone-0020412-g002: Tacrolimus reduces tumor vascularity.MMTVneu tumors from 4 control 20% intralipid mice and 4 tacrolimus treated mice were resected and embedded in paraffin. Immunohistochemistry with antibody to factor VIII was performed as described in “Material and Methods”. Microvessel density was determined by counting the number of microvessels in 3 high-power fields at 200×. A, D) The mean number of microvessels per high power field in control tumors was 104±13. B, D) The mean number of microvessels per high power field in tacrolimus treated tumors was 20±1 (p<0.001). This shows that tacrolimus reduces angiogenesis in vivo. C) Negative control human breast tumor without primary antibody shows no staining.

Mentions: To show whether decreased tumor growth in tacrolimus treated mice correlates with a decrease in tumor angiogenesis, we performed IHC on paraffin embedded tumors from control (20% intralipid, n = 4) mice and tacrolimus treated mice (n = 4). The number of microvessels per high power field for control tumors was 104±13, compared to tacrolimus tumors 20±1, p<0.001 (Fig. 2), indicating that tacrolimus decreased tumor angiogenesis in vivo.


The role of calcineurin/NFAT in SFRP2 induced angiogenesis--a rationale for breast cancer treatment with the calcineurin inhibitor tacrolimus.

Siamakpour-Reihani S, Caster J, Bandhu Nepal D, Courtwright A, Hilliard E, Usary J, Ketelsen D, Darr D, Shen XJ, Patterson C, Klauber-Demore N - PLoS ONE (2011)

Tacrolimus reduces tumor vascularity.MMTVneu tumors from 4 control 20% intralipid mice and 4 tacrolimus treated mice were resected and embedded in paraffin. Immunohistochemistry with antibody to factor VIII was performed as described in “Material and Methods”. Microvessel density was determined by counting the number of microvessels in 3 high-power fields at 200×. A, D) The mean number of microvessels per high power field in control tumors was 104±13. B, D) The mean number of microvessels per high power field in tacrolimus treated tumors was 20±1 (p<0.001). This shows that tacrolimus reduces angiogenesis in vivo. C) Negative control human breast tumor without primary antibody shows no staining.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3108822&req=5

pone-0020412-g002: Tacrolimus reduces tumor vascularity.MMTVneu tumors from 4 control 20% intralipid mice and 4 tacrolimus treated mice were resected and embedded in paraffin. Immunohistochemistry with antibody to factor VIII was performed as described in “Material and Methods”. Microvessel density was determined by counting the number of microvessels in 3 high-power fields at 200×. A, D) The mean number of microvessels per high power field in control tumors was 104±13. B, D) The mean number of microvessels per high power field in tacrolimus treated tumors was 20±1 (p<0.001). This shows that tacrolimus reduces angiogenesis in vivo. C) Negative control human breast tumor without primary antibody shows no staining.
Mentions: To show whether decreased tumor growth in tacrolimus treated mice correlates with a decrease in tumor angiogenesis, we performed IHC on paraffin embedded tumors from control (20% intralipid, n = 4) mice and tacrolimus treated mice (n = 4). The number of microvessels per high power field for control tumors was 104±13, compared to tacrolimus tumors 20±1, p<0.001 (Fig. 2), indicating that tacrolimus decreased tumor angiogenesis in vivo.

Bottom Line: 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).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.

View Article: PubMed Central - PubMed

Affiliation: Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America.

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.

Show MeSH
Related in: MedlinePlus