In Vitro Anti-Neuroblastoma Activity of Thymoquinone Against Neuro-2a Cells via Cell-cycle Arrest.

Arumugam Paramasivam,Gopalswamy Jayaraman,Subramanian Raghunandhakumar,Jayaseelan Vijayashree Priyadharsini

doi:10.7314/apjcp.2015.16.18.8313

Arumugam Paramasivam, Gopalswamy Jayaraman + Show 2 more

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https://doi.org/10.7314/apjcp.2015.16.18.8313

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Abstract

We have recently shown that thymoquinone (TQ) has a potent cytotoxic effect and induces apoptosis via caspase-3 activation with down-regulation of XIAP in mouse neuroblastoma (Neuro-2a) cells. Interestingly, our results showed that TQ was significantly more cytotoxic towards Neuro-2a cells when compared with primary normal neuronal cells. In this study, the effects of TQ on cell-cycle regulation and the mechanisms that contribute to this effect were investigated using Neuro-2a cells. Cell-cycle analysis performed by flow cytometry revealed cell-cycle arrest at G2/M phase and a significant increase in the accumulation of TQ-treated cells at sub-G1 phase, indicating induction of apoptosis by the compound. Moreover, TQ increased the expression of p53, p21 mRNA and protein levels, whereas it decreased the protein expression of PCNA, cyclin B1 and Cdc2 in a dose- dependent manner. Our finding suggests that TQ could suppress cell growth and cell survival via arresting the cell-cycle in the G2/M phase and inducing apoptosis of neuroblastoma cells.

Highlights

Thymoquinone (TQ) is one of the bioactive component of Nigella sativa (Shoieb et al, 2003)
We have recently shown that thymoquinone (TQ) has a potent cytotoxic effect and induces apoptosis via caspase-3 activation with down-regulation of XIAP in mouse neuroblastoma (Neuro-2a) cells
Primary antibodies against p53, p21, proliferating cell nuclear antigen (PCNA), cyclin B1 and Cdc2 were purchased from Santa Cruz Biotechnology (Santa Cruz, CA, USA). β-actin was purchased from Sigma Aldrich Chemicals Pvt Ltd (USA)

Summary

Introduction

Thymoquinone (TQ) is one of the bioactive component of Nigella sativa (Shoieb et al, 2003). Extracts prepared from black seeds of N. sativa have been used for medical purposes for centuries for a number of diseases (Ali and Blunden, 2003; Padhye et al, 2008). TQ is the active ingredient of black seed and has been shown to possess antitumor activity against a broad spectrum of cancer cells, including colon, ovarian, lung, osteosarcoma, and myeloblastic leukemia (Norwood et al, 2006; GaliMuhtasib et al, 2008; Wilson-Simpson et al, 2007; Roepke et al, 2008; El-Mahdy et al, 2005). The selective cytotoxicity of TQ for human cancer cells compared to primary mouse keratinocytes (GaliMuhtasib et al, 2004), mouse normal kidney cells (Shoieb et al, 2003), non-malignant fibroblasts (Effenberger et al, 2010) and normal human lung fibroblasts (Gurung et al, 2010) has been reported in several studies

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