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Updated: Feb 21, 2026
Differentiation of a Human Neural Stem Cell Line on Three Dimensional Cultures, Analysis of MicroRNA and Putative Target Genes
Published on: April 12, 2015
CDDO and ATRA Instigate Differentiation of IMR32 Human Neuroblastoma Cells
Namrata Chaudhari1, Priti Talwar1, Christian Lefebvre D'hellencourt2
1Apoptosis and Cell Survival Research Lab, Department of Biosciences, School of Biosciences and Technology, VIT University, Vellore, India.
Abstract:
Neuroblastoma is the most common solid extra cranial tumor in infants. Improving the clinical outcome of children with aggressive tumors undergoing one of the multiple treatment options has been a major concern. Differentiating neuroblastoma cells holds promise in inducing tumor growth arrest and treating minimal residual disease. In this study, we investigated the effect of partial PPARγ agonist 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO) on human neuroblastoma IMR32 cells. Our results demonstrate that treatment with low concentration of CDDO and particularly in combination with all trans retinoic acid (ATRA) induced neurite outgrowth, increased the percentage of more than two neurites bearing cells, and decreased viability in IMR32 cells. These morphological changes were associated with an increase in expression of bonafide differentiation markers like β3-tubulin and Neuron Specific Enolase (NSE). The differentiation was accompanied by a decrease in the expression of MYCN whose amplification is known to contribute to the pathogenesis of neuroblastoma. MYCN is known to negatively regulate NMYC downstream-regulated gene 1 (NDRG1) in neuroblastomas. MYCN down-regulation induced by CDDO correlated with increased expression of NDRG1. CDDO decreased Anaplastic Lymphoma Kinase (ALK) mRNA expression without affecting its protein level, while ATRA significantly down-regulated ALK. Antagonism of PPARγ receptor by T0070907 meddled with differentiation inducing effects of CDDO as observed by stunted neurite growth, increased viability and decreased expression of differentiation markers. Our findings indicate that IMR32 differentiation induced by CDDO in combination with ATRA enhances, differentiation followed by cell death via cAMP-response-element binding protein (CREB) independent and PPARγ dependent signaling mechanisms.
Insights
Partial PPARγ agonist CDDO combined with ATRA promotes neuroblastoma cell differentiation and reduces viability. This targeted approach shows promise for treating aggressive neuroblastoma by inducing cell death through PPARγ-dependent pathways.
Area of Science:
- Oncology
- Molecular Biology
- Cell Biology
Background:
- Neuroblastoma is a common pediatric cancer.
- Differentiating neuroblastoma cells offers a potential therapeutic strategy.
- Targeting aggressive tumor cell behavior is a clinical concern.
Purpose of the Study:
- To investigate the effects of CDDO, a partial PPARγ agonist, on human neuroblastoma IMR32 cells.
- To evaluate the combined effect of CDDO and ATRA on neuroblastoma cell differentiation and viability.
- To elucidate the underlying signaling mechanisms, including PPARγ and MYCN involvement.
Main Methods:
- Treatment of IMR32 neuroblastoma cells with CDDO and ATRA.
- Assessment of cell morphology, viability, and differentiation markers (β3-tubulin, NSE).
- Analysis of gene expression for MYCN, NDRG1, and ALK.
- Pharmacological antagonism of the PPARγ receptor.
Main Results:
- CDDO, especially with ATRA, induced neurite outgrowth and increased differentiation markers in IMR32 cells.
- Cell viability decreased upon treatment with CDDO and ATRA.
- MYCN expression was downregulated, correlating with increased NDRG1 expression.
- CDDO reduced ALK mRNA, while ATRA downregulated ALK protein; PPARγ antagonism blocked CDDO's effects.
Conclusions:
- CDDO in combination with ATRA effectively induces neuroblastoma cell differentiation and subsequent cell death.
- The differentiation process is mediated through PPARγ-dependent and CREB-independent signaling pathways.
- This combination therapy presents a promising strategy for managing aggressive neuroblastoma.
