Evaluation of the potential therapeutic effects of curcumin and lycopene in adult malignant brain tumour cells in vitro

Glioblastoma multiforme are the most challenging of cancers to treat and even with recent advances in therapeutic approaches, the prognosis following diagnosis remains poor. Novel therapeutic approaches able to target such tumours without resulting in significant toxicity are needed. Micronutrients have been shown to exert potential therapeutic effects in cell culture and animal models which include anti-cancer activity and other functional properties such as anti-microbial and anti-oxidative effects. The aim of this research was to investigate the anticancer properties of curcumin (77% pure, derived from the ground rhizome of turmeric) and LycoRed powder (containing 10% lycopene from tomato extract) on four primary brain tumour-biopsy derived cell cultures (glioblastoma multiforme malignant cells) using a normal brain cell line as control (CC2565; passage 10 and above).
The morphological appearance of the normal brain cell line and glioblastoma cell cultures was compared under phase contrast microscopy. The cytotoxicity of curcumin and Lycored was determined using a DRAQ 7 cell viability assay. Expression of antigens linked to invasive, angiogenic and apoptotic potential was studied using immunocytochemistry and flow cytometry. Induction of apoptosis was investigated using flow cytometry via Annexin-V staining. Anti-invasive and anti-angiogenic potentials were studied using a FluoroBlok invasion and angiogenesis assay (co-culture method) in vitro, respectively.
Brain tumour-biopsy derived cell cultures incubated for 24h with increasing concentrations of curcumin showed significant decreased in cell viability (IC75,50,25 values 14.2 to 19.5μg/ml). LycoRed was not found to affect the cell viability of tumour cells ad no IC values could be established; only curcumin was therefore investigated in subsequent assays (using IC75 concentration). Neither curcumin nor LycoRed showed toxicity to normal brain cells.
No significant induction of apoptosis by curcumin was observed in the primary brain tumour cells studied. However, three of the primary brain tumour cell cultures investigated were high in invasive capacity and curcumin treatment at IC75 concentration reduced the percentage of invasion after only 24 hours of incubation. In addition, curcumin was found to have antiangiogenic properties in vitro. In the normal brain cell culture, each parameter (number of nodes, junctions and branches) was maintained when treated with increasing concentrations of curcumin (0 to 40μg/ml). When all glioblastoma cell cultures and normal brain cells showed strong positivity for GFAP confirming that they are astrocytic in origin, expression of other antigens studied (Beta-1-integrin, CD44, VEGF, MMP-14, NG2, GD3) varied between the primary brain tumour cell cultures. This suggests that the invasive or angiogenic capacity of the gliobalstoma cell cultures investigated may not be attributable to one common factor as has been reported before, but perhaps an integration of many factors with overlapping functions.
In conclusion, the results indicate that curcumin may have anti cancer properties through inhibition of invasion and angiogenesis in these malignant glioblastomas. Further studies are necessary to establish whether LycoRed possesses therapeutic potential.