Characterizing the Activity of Three Novel Differentiation-Inducing Compounds in Neuroblastoma Cells
Neuroblastoma is the most common extracranial tumor in children. It makes up 8% of all childhood cancers and is the cause of 15% of all childhood cancer-related deaths. Neuroblastoma arises from neural crest precursor cells that fail to differentiate into mature neurons. The biggest threat for high-risk neuroblastoma patients is treatment-resistant relapse due to minimal residual disease. Current post-remission maintenance therapy includes the use of differentiation agent 13-cis-retinoic acid. However, approximately 50% of patients treated become unresponsive to this agent. The discovery of new differentiation agents is necessary in order to treat patients resistant to current available therapies. Using a high content phenotypic screening of a Chembridge small molecule library, three novel neurite-inducing small molecules (Compounds 3, 4, and 10) were identified. The objective of my study is to determine whether the hit compounds have a generic differentiation-inducing effect in neuroblastoma cells with different genetic backgrounds, and whether that the induced cell differentiation by these compounds is coupled with cell cycle arrest and apoptosis. Our results demonstrate that treatment with compounds 3, 4, and 10 increase neurite outgrowth in BE(2)-C and KELLY cells. Compound 3 is validated to induce differentiation through at least two molecular differentiation markers in BE(2)-C, KELLY and CHLA-90 cells. It also has a generic effect on suppressing cell proliferation and decreasing cell viability generically. Western blot analysis, the differentiation inducing activity of compound 4 is validated BE(2)-C and KELLY cells. Compound 4 also decreases cell viability and inhibits proliferation generically. Through an apoptosis assay, compound 4 induced apoptosis in BE(2)-C and KELLY cells. The differentiation inducing activity of compound 10 was validated in BE(2)-C, KELLY and CHLA-90 cells. Compound 10 decreased cell viability in cell lines BE(2)-C and CHLA-90, suggesting its activity might be cell-type specific. It inhibits proliferation in the four cell lines and induces apoptosis in BE(2)-C and KELLY cells. In summary, my findings suggest that compound 3 is the best candidate out of the three hit compounds. Future investigations are needed to further characterize the differentiation inducing activity in multiple cell lines, the mechanisms of reducing cell viability, and effect on cell cycle distribution.
neuroblastoma, HCS, hit compounds, differentiation
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