Abstract
INTRODUCTION: Diffuse intrinsic pontine glioma (DIPG) is one of the most aggressive paediatric brainstem tumours, with a dismal prognosis and a 90% mortality rate within 2 years. Over the last 50 years, DIPG patients have seen no increase in survival, owing to progress being hindered by a lack of tissue available for in-vitro study, the critical anatomical location of the pons and the impermeability of the blood-brain barrier (BBB). In this in-vitro study, we describe the use of cancer gene therapy using the targeted-bacteriophage vector to deliver the therapeutic TNFα transgene to DIPG cells, in combination with the novel therapeutic, curcumin, which constitutes the spice turmeric (Curcuma longa). MATERIALS AND METHODS: We evaluated the in-vitro cytotoxicity of curcumin in 2D tissue cultures of primary DIPG cells, with cell-viability measured after treatment with varying concentrations of curcumin for 72 hours. Next, we assessed the gene transduction and cell-killing efficacy of the targeted-hybrid bacteriophage, using the Luciferase and TNFα transgenes, at day 3 post-transduction. Lastly, we assessed the effect of combination therapy by adding concentrations of curcumin to DIPG cells at day 3 post-transduction by the bacteriophage, once again evaluating Luciferase expression and cell-killing. DISCUSSION: Here, we report for the first time, the in-vitro cytotoxicity of curcumin in this DIPG cell line, with significant cell death seen at as low as 37.5μM. Secondly, we show that primary DIPG cells can be successfully transduced with the targeted-modified bacteriophage vector, containing the TNFα gene, leading to TNFα-mediated cell death. Lastly, we show that the combination of curcumin with the targeted-bacteriophage vector led to enhanced DIPG cell death, due to increased bacteriophage-mediated transgene expression. CONCLUSION: We have shown that combination chemovirotherapy of curcumin and the targeted bacteriophage is efficacious in-vitro, warranting further in-vivo work to assess the safety and efficacy after systemic delivery.