1. Chromogranin A regulates neuroblastoma proliferation and phenotype
- Author
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Zhang, Dongyun, Babayan, Lilit, Ho, Hillary, and Heaney, Anthony P
- Subjects
Biochemistry and Cell Biology ,Biomedical and Clinical Sciences ,Biological Sciences ,Pediatric Cancer ,Neurosciences ,Pediatric ,Rare Diseases ,Biotechnology ,Cancer ,Neuroblastoma ,Chromogranin A ,Insulin-like growth factor ,Differentiation therapy ,Other Biological Sciences ,Biological sciences ,Biomedical and clinical sciences ,Environmental sciences - Abstract
Neuroblastoma is a commonly encountered solid tumor in early childhood with high neuroplasticity, and differentiation therapy is hypothesized to lead to tumor mass shrinkage and/or symptom relief. CgA is a tissue specific protein restricted to the diffuse neuroendocrine system, and widely expressed in neuroblastomas. Using knockdown and knockout approaches to deplete CgA levels, we demonstrated that CgA loss inhibits SH-SY5Y cell proliferation and leads to a morphological shift with increased expression of Schwann and extracellular matrix specific molecules, and suppression of chromaffin features. We further confirmed the effects of CgA in a series of neuroblastoma cells with [BE(2)-M17 and IMR-32] and without (SK-N-SH) N-Myc amplification. We demonstrated that CgA depletion reduced IGF-II and IGFBP-2 expression, increased IGFBP-3 levels, and suppresses IGF downstream signaling as evidenced by reduced AKT/ERK pathway activation. This was further supported by an increased anti-proliferative effect of the ERK inhibitor in the CgA depleted cells. In an in vivo xenograft neuroblastoma model, CgA knockdown led to increased S-phenotypic marker expression at both protein and mRNA levels. Together these results suggest that CgA maintains IGF secretion and intracellular signaling to regulate proliferation and differentiation in neuroblastomas.
- Published
- 2019