Gene Expression Changes in Spleens and Livers of Tumour-Bearing Mice Suggest Delayed Inflammation and Attenuated Cachexia in Response to Oil Palm Phenolics

Background/Aim: Plant phenolics can inhibit, retard or reverse carcinogenesis, and may thus help prevent or treat cancer. Oil palm phenolics (OPP) previously showed anti-tumour activities in vivo via a cytostatic mechanism at 1,500 ppm gallic acid equivalent. Here, we report other possible molecular mechanisms by which this extract attenuates cancer, especially those concerning the immune response. Methods: We subcutaneously injected J558 myeloma cells in BALB/c mice and supplemented OPP orally at 1,500 ppm gallic acid equivalent. We observed the physiology parameters of these animals and harvested their spleens and livers after 18 h, 1 week and 4 weeks for microarray gene expression analysis using Illumina MouseRef-8 BeadChips. Results: Time course microarray analysis on spleens after injecting J558 myeloma cells in mice revealed that the immune response of tumour-bearing mice supplemented with OPP was lower compared to controls, thus suggesting delayed inflammation in response to OPP. In livers, cholesterol biosynthesis genes were upregulated while inflammatory genes were downregulated through time, further suggesting attenuation of systemic inflammation and cachexia. These effects correlated with the delayed in vivo development of syngeneic tumours in mice given OPP. Conclusions: This study suggests the possible utilisation of OPP as an anti-tumour and anti-cachexia agent.