Limits...
Phosphodiesterase 4D acts downstream of Neuropilin to control Hedgehog signal transduction and the growth of medulloblastoma.

Ge X, Milenkovic L, Suyama K, Hartl T, Purzner T, Winans A, Meyer T, Scott MP - Elife (2015)

Bottom Line: The consequent inhibition of protein kinase A (PKA) enhances Hh transduction.In the developing cerebellum, genetic removal of Neuropilins reduces Hh signaling activity and suppresses proliferation of granule neuron precursors.In mouse medulloblastoma allografts, PDE4D inhibitors suppress Hh transduction and inhibit tumor growth.

View Article: PubMed Central - PubMed

Affiliation: Department of Developmental Biology, Department of Genetics, Department of Bioengineering, Stanford University School of Medicine, Stanford, United States.

ABSTRACT
Alterations in Hedgehog (Hh) signaling lead to birth defects and cancers including medulloblastoma, the most common pediatric brain tumor. Although inhibitors targeting the membrane protein Smoothened suppress Hh signaling, acquired drug resistance and tumor relapse call for additional therapeutic targets. Here we show that phosphodiesterase 4D (PDE4D) acts downstream of Neuropilins to control Hh transduction and medulloblastoma growth. PDE4D interacts directly with Neuropilins, positive regulators of Hh pathway. The Neuropilin ligand Semaphorin3 enhances this interaction, promoting PDE4D translocation to the plasma membrane and cAMP degradation. The consequent inhibition of protein kinase A (PKA) enhances Hh transduction. In the developing cerebellum, genetic removal of Neuropilins reduces Hh signaling activity and suppresses proliferation of granule neuron precursors. In mouse medulloblastoma allografts, PDE4D inhibitors suppress Hh transduction and inhibit tumor growth. Our findings reveal a new regulatory mechanism of Hh transduction, and highlight PDE4D as a promising target to treat Hh-related tumors.

No MeSH data available.


Related in: MedlinePlus

PDE4D knockdown reduces Hh signaling activity.(A) Western blot shows that lentivirus-mediated expression of shRNA against PDE4D abolished the expression of endogenous PDE4D2/6. (B) On day 3, Hh signaling activity was evaluated after cells were treated with Shh. Gli1 transcript level was measured by qPCR to evaluate Hh signaling activity. Data are mean ± SEM. Statistics: Student's t-Test. **p < 0.01, ***p < 0.001.DOI:http://dx.doi.org/10.7554/eLife.07068.013
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4569902&req=5

fig4s2: PDE4D knockdown reduces Hh signaling activity.(A) Western blot shows that lentivirus-mediated expression of shRNA against PDE4D abolished the expression of endogenous PDE4D2/6. (B) On day 3, Hh signaling activity was evaluated after cells were treated with Shh. Gli1 transcript level was measured by qPCR to evaluate Hh signaling activity. Data are mean ± SEM. Statistics: Student's t-Test. **p < 0.01, ***p < 0.001.DOI:http://dx.doi.org/10.7554/eLife.07068.013

Mentions: We then used shRNA to silence the expression of PDE4D in NIH3T3 cells, and assessed Hh signal transduction. Without PDE4D, the Shh-induced Hh signal transduction was significantly reduced (Figure 4—figure supplement 2). These data are fully consistent with a view of PDE4D as a positive regulator of Hh transduction. The SAG result indicates that PDE4D operates in the Hh pathway at the level of Smo or downstream.


Phosphodiesterase 4D acts downstream of Neuropilin to control Hedgehog signal transduction and the growth of medulloblastoma.

Ge X, Milenkovic L, Suyama K, Hartl T, Purzner T, Winans A, Meyer T, Scott MP - Elife (2015)

PDE4D knockdown reduces Hh signaling activity.(A) Western blot shows that lentivirus-mediated expression of shRNA against PDE4D abolished the expression of endogenous PDE4D2/6. (B) On day 3, Hh signaling activity was evaluated after cells were treated with Shh. Gli1 transcript level was measured by qPCR to evaluate Hh signaling activity. Data are mean ± SEM. Statistics: Student's t-Test. **p < 0.01, ***p < 0.001.DOI:http://dx.doi.org/10.7554/eLife.07068.013
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4569902&req=5

fig4s2: PDE4D knockdown reduces Hh signaling activity.(A) Western blot shows that lentivirus-mediated expression of shRNA against PDE4D abolished the expression of endogenous PDE4D2/6. (B) On day 3, Hh signaling activity was evaluated after cells were treated with Shh. Gli1 transcript level was measured by qPCR to evaluate Hh signaling activity. Data are mean ± SEM. Statistics: Student's t-Test. **p < 0.01, ***p < 0.001.DOI:http://dx.doi.org/10.7554/eLife.07068.013
Mentions: We then used shRNA to silence the expression of PDE4D in NIH3T3 cells, and assessed Hh signal transduction. Without PDE4D, the Shh-induced Hh signal transduction was significantly reduced (Figure 4—figure supplement 2). These data are fully consistent with a view of PDE4D as a positive regulator of Hh transduction. The SAG result indicates that PDE4D operates in the Hh pathway at the level of Smo or downstream.

Bottom Line: The consequent inhibition of protein kinase A (PKA) enhances Hh transduction.In the developing cerebellum, genetic removal of Neuropilins reduces Hh signaling activity and suppresses proliferation of granule neuron precursors.In mouse medulloblastoma allografts, PDE4D inhibitors suppress Hh transduction and inhibit tumor growth.

View Article: PubMed Central - PubMed

Affiliation: Department of Developmental Biology, Department of Genetics, Department of Bioengineering, Stanford University School of Medicine, Stanford, United States.

ABSTRACT
Alterations in Hedgehog (Hh) signaling lead to birth defects and cancers including medulloblastoma, the most common pediatric brain tumor. Although inhibitors targeting the membrane protein Smoothened suppress Hh signaling, acquired drug resistance and tumor relapse call for additional therapeutic targets. Here we show that phosphodiesterase 4D (PDE4D) acts downstream of Neuropilins to control Hh transduction and medulloblastoma growth. PDE4D interacts directly with Neuropilins, positive regulators of Hh pathway. The Neuropilin ligand Semaphorin3 enhances this interaction, promoting PDE4D translocation to the plasma membrane and cAMP degradation. The consequent inhibition of protein kinase A (PKA) enhances Hh transduction. In the developing cerebellum, genetic removal of Neuropilins reduces Hh signaling activity and suppresses proliferation of granule neuron precursors. In mouse medulloblastoma allografts, PDE4D inhibitors suppress Hh transduction and inhibit tumor growth. Our findings reveal a new regulatory mechanism of Hh transduction, and highlight PDE4D as a promising target to treat Hh-related tumors.

No MeSH data available.


Related in: MedlinePlus