Neurotrophins (NTs) bind to two different classes of cell surface receptors, Trk receptor tyrosine kinases and p75NTR, both of which are expressed by neuroblastoma cells.
Northern blotting and nuclear run-on analyses demonstrated that transcription is a primary determinant of both cell-specific and variable expression of the TrkA gene in neuroblastoma cell lines that express it to different degrees.
Recently, we highlighted that the ganglioside GM1 promotes neuroblastoma cells differentiation by activating the TrkA receptor through the formation of a TrkA-GM1 oligosaccharide complex at the cell surface.
The aim of the present study was to investigate the effect of As<sub>2</sub>O<sub>3</sub> on Trk expression in NB cell lines and its potential therapeutic efficacy.
The anaplastic lymphoma kinase (ALK) is a tyrosine kinase receptor that is involved in the pathogenesis of different types of human cancers, including neuroblastoma (NB).
The expression of gp140TRK-A mRNA correlates with distinct biologic and clinical subsets of neuroblastoma, which suggests a role for the high-affinity nerve growth factor receptors in determining the phenotype of neuroblastoma.
The MP-N-TS cell line should be useful for clarifying the TRK-A and TRK-B signaling pathways responsible for the different prognoses in patients with NB.
The over-expressions of brain-derived neurotrophic factor (BDNF) and its tyrosine kinase receptor TrkB have been reported to induce chemo-resistance in neuroblastoma (NB) cells.
The treatment of NB cells with metformin or MIBG resulted in an increased expression of genes encoding biomarkers for favorable outcome in NB [(ephrin (EFN)B2, EFNB3, EPH receptor B6 (EPHB6), neurotrophic tyrosine kinase, receptor, type 1 (NTRK1), CD44 and Myc-interacting zinc finger protein (MIZ-1)] and tumor suppressor genes [(early growth response 1 (EGR1), EPH receptor A2 (EPHA2), growth arrest and DNA-damage-inducible, beta (GADD45B), neuregulin 1 (NRG1), TP53 apoptosis effector (PERP) and sel-1 suppressor of lin-12-like (C. elegans) (SEL1L)].
Thus, the restoration of the NGF-induced differentiation pathway by exogenous TRK-A presents a system of NGF-responsive human cultured cells and focuses attention on the trk-A protein and its function or malfunction in neuroblastoma.
We suggest that the transcriptional program of neuroblastoma cells is modulated by Trk-receptor expression and basal activation rather than by ligand-induced activation.