BDNF and PDE4, but not the GRPR, Regulate Viability of Human Medulloblastoma Cells

Abstract

Medulloblastoma is the most common brain tumor of childhood. Emerging molecular targets in medulloblastoma include neurotrophin and neuropeptide receptors. In the present study, we have examined the influence of brain-derived neurotrophic factor (BDNF)/TrkB receptor- and gastrin-releasing peptide receptor (GRPR)-mediated signaling on the viability of human medulloblastoma cells. The expression of TrkB and GRPR was confirmed by immunohistochemistry and mRNA for both BDNF and GRPR was detected by reverse transcriptase polymerase chain reaction in Daoy, D283, and ONS76 cells. Treatment with BDNF significantly inhibited the viability of Daoy and D283, but not ONS76 cells, measured with the MTT assay. Neither the GRPR agonists GRP and bombesin nor the GRPR antagonist RC-3095 affected cell viability. Because previous findings have indicated that the viability of glioma cells might be enhanced by GRP when combined with the cAMP phosphodiesterase-4 (PDE4) inhibitor rolipram, we also examined the effects of rolipram alone or combined with GRP on cell viability. Rolipram significantly reduced the viability of all three cell lines, and the inhibitory effect of rolipram in Daoy cells was not modified by cotreatment with GRP. The results suggest that BDNF/TrkB and PDE4, but not the GRPR, regulate the viability of medulloblastoma cells.

Gastrin-releasing peptide receptors in the central nervous system: role in brain function and as a drug target

“…These findings strongly suggest that targeting GRPR may be a promising strategy for the development of novel therapies against glioma. The GRPR might also regulate the growth of neuroblastoma (Kim et al, 2002; Qiao et al, 2008; Abujamra et al, 2009), although, in contrast, we could not find a role for GRPR in regulating the in vitro growth of medulloblastoma, the most common brain cancer of childhood (Schmidt et al, 2009). …”

BDNF/TrkB Content and Interaction with Gastrin-Releasing Peptide Receptor Blockade in Colorectal Cancer

“…The cells which grew the least were confluent and they were detached with a trypsin/EDTA solution. After centrifugation, the cell pellet was resuspended in 3 ml of formol and embedded into paraffin wax [17,19,22]. For analysis in tumor samples, 4-µm-thick sections were mounted on organosilane-coated slides and dried overnight at 37°C.…”

“…Briefly, the medium was removed, cells were washed with Hanks’ Balanced Salt Solution (Invitrogen), and 100 µl of 0.25% trypsin/EDTA solution was added to detach the cells, which were counted immediately in a hemocytometer. Proliferation was also measured by MTT assay as previously described [17,22]. The cells were washed with Hanks’ Balanced Salt Solution (Invitrogen), 11 µl of MTT (5 mg/ml; Sigma-Aldrich) was added to each well, and they were then incubated for 4 h at 37°C.…”

Neuronal Activity in Ontogeny and Oncology

“…Recent studies showed that p75NTR is expressed predominantly in the SHH subgroup [107], but the functional consequence of this remains to be determined. BDNF and TrkB signaling effects in medulloblastoma are even less clear, with one study reporting exposure to BDNF and reduced viability in human medulloblastoma cell lines [108]; but another study reporting a similar effect with TrkB inhibition [109]. The function of neurotrophin signaling in ependymomas is also an area that requires investigation.…”