Brazilin induces T24 cell death through c-Fos and GADD45ß independently regulated genes and pathways.

Purified Brazilin from Sappan wood extract has been reported with significant antitumor effect, especially on human T24 cells and bladder cancer mouse models. Brazilin can significantly induce expression of c-Fos and GADD45ß and transfection expression of c-Fos and GADD45ß in T24 cells can induce significant cell morphology changes, reduced viability and cell death, while transfection of siRNA-c-Fos and siRNA-GADD45ß can reverse the induced cell death. Co-transfection of both c-Fos and GADD45ß into T24 cells resulted in a significantly additive effect when compared to single transfection with only c-Fos or GADD45ß. Meanwhile, transfection of interfering siRNA-c-Fos or siRNA-GADD45ß can partially rescue the cell viability and siRNA co-transfection showed increased rescue rate. The transfection expression and interference with pcDNA3.1-c-Fos/siRNA-c-Fos or pcDNA3.1-GADD45ß/siRNA-GADD45ß did not affect each other's expression. Moreover, analysis of c-Fos and GADD45ß regulated genes and signal pathways showed that no common regulated genes or pathways were present. All the results indicated that c-Fos and GADD45ß mediate independent Brazilin-inducible genes and pathways. © 2018 IUBMB Life, 70(11):1101-1110, 2018.

c-Fos is involved in inhibition of human bladder carcinoma T24 cells by brazilin.

Crude brazilin extract from Sappan wood has demonstrated strong anti tumor activity in the mouse model of human bladder carcinoma and clinical trial for intravesical therapy. Purified brazilin was confirmed the most active molecule in inhibition of bladder carcinoma T24 cells. Brazilin decreased proliferation and viability of T24 cells in a dose- and time-dependent manner, with a calculated LC50 of 32 µg/mL. More than 1,000 of genes were found upregulated and down regulated by brazilin treatment in digital gene expression profiling. Gene ontology analysis indicated that stress response, apoptosis, and cell cycle regulatory pathways were highly enriched. Among the regulated genes, c-Fos was the most and specifically upregulated. Overexpression of c-Fos in T24 cells resulted in tumor cell specific changes in cell morphology and viability. Over expression of stress-responsive gene, HSP70, and other highly upregulated genes did not have any effect on cell growth. Brazilin may inhibit T24 cell growth and trigger cell death through a c-Fos-mediated and tumor cell specific signaling pathway. Further studies of its down stream mediators may help to identify better tumor cell type specific drug targets.

Dietary intake of folate, vitamin B6, and vitamin B12, genetic polymorphism of related enzymes, and risk of breast cancer: a case-control study in Brazilian women.

BACKGROUND: Several studies have determined that dietary intake of B vitamins may be associated with breast cancer risk as a result of interactions between 5,10-methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MTR) in the one-carbon metabolism pathway. However, the association between B vitamin intake and breast cancer risk in Brazilian women in particular has not yet been investigated. METHODS: A case-control study was conducted in São Paulo, Brazil, with 458 age-matched pairs of Brazilian women. Energy-adjusted intakes of folate, vitamin B6, and vitamin B12 were derived from a validated Food Frequency Questionnaire (FFQ). Genotyping was completed for MTHFR A1298C and C677T, and MTR A2756G polymorphisms. A logistical regression model was used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). RESULTS: Neither dietary intake of folate, vitamin B6, or vitamin B12 nor MTHFR polymorphisms were independently associated with breast cancer risk. Analysis stratified by menopausal status showed a significant association between placement in the highest tertile of folate intake and risk of breast cancer in premenopausal women (OR = 2.17, 95% CI: 1.23-3.83; P trend = 0.010). The MTR 2756GG genotype was associated with a higher risk of breast cancer than the 2756AA genotype (OR = 1.99, 95% CI = 1.01-3.92; P trend = 0.801), and statistically significant interactions with regard to risk were observed between the MTHFR A1298C polymorphism and folate (P = 0.024) or vitamin B6 (P = 0.043), and between the MTHFR C677T polymorphism and folate (P = 0.043) or vitamin B12 (P = 0.022). CONCLUSION: MTHFR polymorphisms and dietary intake of folate, vitamin B6, and vitamin B12 had no overall association with breast cancer risk. However, increased risk was observed in total women with the MTR 2756GG genotype and in premenopausal women with high folate intake. These findings, as well as significant interactions between MTHFR polymorphisms and B vitamins, warrant further investigation.