Sonic Hedgehog pathway is essential for neuroblastoma cell proliferation and tumor growth

Abstract

Accumulated evidence suggests a major role for the activation of the Sonic Hedgehog (SHH) signaling pathway in the development of neural crest stem cells that give rise to the sympathetic nervous system. We therefore investigated the involvement of SHH signaling in the pathogenesis of neuroblastoma (NB), a common childhood malignant tumor of the sympathetic nervous system. Inhibition of SHH signaling by cyclopamine induced apoptosis and blocked proliferation in all major types of NB cells, and abrogated the tumorigenicity of NB cells. Our study has revealed a molecular mechanism for the persistent activation of the SHH pathway which promotes the development of NB, and suggests a new approach for the treatment of this childhood malignant tumor.

Sonic Hedgehog in cancer stem cells: a novel link with autophagy

“…To date, a relationship between the SHH and autophagy pathways has not been reported, although it has been shown that there are cancers that are sensitive to both pathways, as for instance neuroblastoma (Mao et al, 2009;Mohan et al, 2011;Xu et al, 2012).…”

Smoothened-independent activation of hedgehog signaling by rearranged during transfection promotes neuroblastoma cell proliferation and tumor growth

“…5 μg total RNA in a volume of 20 μl was reversely transcribed by using SuperScript III reagent (Life Technologies) and the oligo-(deoxythymidine) primers followed by incubation at 42°C for 1 h. After termination of cDNA synthesis, each reaction mixture was diluted with 80 μl Tris-EDTA buffer. Messenger RNA levels of target genes were determined by quantitative RT-PCR as described previously [16,22]. The relative amounts of the mRNA levels of the target genes from triplicates were normalized to the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and β-actin levels, respectively, and the relative difference in mRNA levels was calculated by 2 − ΔΔCt method.…”

“…Transient transfection and dual-luciferase assay were performed as previously described [15,16]. Briefly, after plated in 24-well plates for 24 h, SH-SY5Y cells in the serum-free medium were transfected with 2 μg GLI-luciferase reporter construct and 0.02 μg pRL-null expressing Renilla luciferase by using Lipofectamine 2000 reagent (Life Technologies) for 6 h. In some cases, the cells were co-transfected with RET-or AKT*-expressing plasmid at 0.2 μg each.…”

“…Overall, the conserved effect of HH is to switch the GLI transcription factors from repressors into activators and allows for fine-tuned transcriptional events. Accumulated evidence has substantiated that HH signaling is essential for NB cell proliferation and tumor growth and that high activity of HH signaling is associated with the cancer stem cell phenotypes and heterogeneous clinical behavior of NB [16][17][18].…”

“…Despite the fact that both GDNF/RET and HH/GLI pathways are crucial for the biological behaviors of NB and that activation of HH/GLI induces the expression of RET in NB cells [11,12,[16][17][18][19], whether GDNF/RET signal through HH pathway in biological behaviors of NB remains unknown. Here, we have shown that RET activates protein kinase B (AKT) to inhibit glycogen synthesis kinase-3β (GSK3β), resulting in activation of HH signaling and subsequent induction of NB cell proliferation and tumor growth.…”