METHODS: This cross-sectional study aimed to evaluate (i) the effect of FTO rs9930506 on obesity and related parameters and (ii) the influence of diet on the above association in Malaysian adults. In total, 79 obese and 99 nonobese Malaysian adults were recruited.
RESULTS: In comparison with Chinese and Malays, Indians had significantly higher waist circumference (P ≤ 0.001 and P = 0.016), waist-hip ratio (P = 0.001 and P < 0.001), body fat percentage (P = 0.001 and P = 0.042), fasting insulin (P = 0.001 and P = 0.001), homeostatic model assessment-insulin resistance (P = 0.001 and P = 0.001) and lower high-density lipoprotein-cholesterol levels (P < 0.001 and P < 0.001), respectively. Indians consumed significantly lower dietary cholesterol (P = 0.002), percentage energy from protein (P < 0.001) and higher fibre (P = 0.006) compared to the other two groups. Malaysian Indians expressed the highest risk allele frequency (G) of FTO rs9930506 compared to the Malays and the Chinese (P < 0.001). No significant association was found between FTO rs9930506 and obesity (dominant model). Risk allele carriers (G) consumed significantly lower vitamin E (P = 0.020) and had a higher fibre intake (P = 0.034) compared to the noncarriers (A). Gene-diet interaction analysis revealed that risk allele carriers (G) had lower high sensitivity C-reactive protein (hsCRP) levels with higher energy from protein (≥14% day-1 ; P = 0.049) and higher vitamin E (≥5.4 mg day-1 ; P = 0.038).
CONCLUSIONS: The presence of the risk allele (G) of FTO rs9930506 was not associated with an increased risk of obesity. Malaysian Indians had a significantly higher frequency of the risk allele (G). Indian participants expressed higher atherogenic phenotypes compared to Chinese and Malays. FTO rs9930506 may interact with dietary protein and vitamin E and modulate hsCRP levels.
PURPOSE: We adopted a combinatorial approach with the joint application of γ-tocotrienol and jerantinine A at lower concentrations in order to minimize toxicity towards non-cancerous cells while improving the potency on brain cancer cells.
METHODS: The antiproliferative potency of individual γ-tocotrienol and jerantinine A as well as combined in low-concentration was firstly evaluated on U87MG cancer and MRC5 normal cells. Morphological changes, DNA damage patterns, cell cycle arrests and the effects of individual and combined low-concentration compounds on microtubules were then investigated. Finally, the potential roles of caspase enzymes and apoptosis-related proteins in mediating the apoptotic mechanisms were investigated using apoptosis antibody array, ELISA and Western blotting analysis.
RESULTS: Combinatorial study between γ-tocotrienol at a concentration range (0-24µg/ml) and fixed IC20 concentration of jerantinine A (0.16µg/ml) induced a potent antiproliferative effect on U87MG cells and led to a reduction on the new half maximal inhibitory concentration of γ-tocotrienol (i.e.tIC50=1.29µg/ml) as compared to that of individual γ-tocotrienol (i.e. IC50=3.17µg/ml). A reduction on undesirable toxicity to MRC5 normal cells was also observed. G0/G1 cell cycle arrest was evident on U87MG cells receiving IC50 of individual γ-tocotrienol and combined low-concentration compounds (1.29µg/ml γ-tocotrienol + 0.16µg/ml jerantinine A), whereas, a profound G2/M arrest was evident on cells treated with IC50 of individual jerantinine A. Additionally, individual jerantinine A and combined compounds (except individual γ-tocotrienol) caused a disruption of microtubule networks triggering Fas- and p53-induced apoptosis mediated via the death receptor and mitochondrial pathways.
CONCLUSIONS: These findings demonstrated that the combined use of lower concentrations of γ-tocotrienol and jerantinine A induced potent cytotoxic effects on U87MG cancer cells resulting in a reduction on the required individual concentrations and thereby minimizing toxicity of jerantinine A towards non-cancerous MRC5 cells as well as probably overcoming the high-dose limiting application of γ-tocotrienol. The multi-targeted mechanisms of action of the combination approach have shown a therapeutic potential against brain cancer in vitro and therefore, further in vivo investigations using a suitable animal model should be the way forward.