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Vanillin is a naturally occurring compound and food-flavoring agent with antioxidant and antimutagenic activities. In present study, we explored the radioprotective effect of a novel vanillin derivative VND3207 (4-hydroxy-3,5-dimethoxybenzaldehyde). VND3207 has a much higher potential in scavenging hydroxyl radical and superoxide radical than vanillin as indicated in the ESR spin-trapping measurement, and it can effectively protect plasmid DNA against 10-50 Gy gamma-ray induced breaks in vitro at the concentrations as low as 10-20 microM. Using human lymphoblastoid AHH-1 cells and human fibroblastoid HFS cells, we demonstrated that VND3207 at 5-40 microM concentrations significantly attenuated the inhibition of proliferation and occurrence of apoptosis produced by 1-8 Gy gamma-irradiation. In the cultured cells, VND3207 significantly decreased the initial production and residual level of DNA double-strand breaks (DSBs) induced by 2 or 8 Gy irradiation. Treatment of VND3207 enhanced the level of DNA-PKcs protein, a critical component of DNA DSB repair pathway in the cells with or without gamma-irradiation. Consistently, the phosphorylation of Akt protein, a mediator of survival signal, as well as its substrate GSK3beta was concurrently increased by VND3207. Our results suggest that VND3207 has radioprotection effect through its capabilities as a powerful antioxidant, in minimizing DNA damage, and activating survival signal Akt pathway, and it may be of value in the development of radioprotective compounds.

Autophagy is a regulated lysosomal pathway involving the bulk degradation of cytoplasmic contents, and is an emerging attractive therapeutic approach for treating cancers. In the present study, we demonstrates that bromovanin (6-bromine-5-hydroxy-4-methoxybenzaldehyde), a vanillin derivative, exhibits a potent antiproliferative effect on a broad spectrum of cancer cell lines, but it induces apoptosis with a large variation in extent on different cancer cell lines. Ultrastructural observation in transmission electron microscopy reveals that autophagy is another type of cell death induced by bromovanin in HepG2 cells. Treatment with bromovanin significantly increases cellular ROS level as well as elicits DNA double-strand breaks as indicated by comet assay and the increased phosphorylated H2AX. Cleavage and inactivation of DNA-PKcs induced by bromovanin is found to occur concurrently with a rapid destruction of c-Myc oncoprotein. These multiple effects of bromovanin, especially the induction of both apoptosis and autophagy, make it very appealing for the development as a novel anticancer drug.

Vanillin, a naturally occurring food component, has been reported to have anti-mutagenic and anti-metastatic potentials, and to inhibit DNA-PKcs activity. However, vanillin itself exhibits very weak antiproliferative activity. We explored the effects of bromovanin (6-bromine-5-hydroxy-4-methoxybenzaldehyde), a novel vanillin derivative, on survival and cell-cycle progression of human Jurkat leukemia cells. Treatment with >10 microM bromovanin significantly elicited apoptosis and G2/M arrest in Jurkat cells in a dose- and time-dependent manner. Bromovanin-induced DNA double-strand breaks (DSB) were demonstrated by means of comet assay as well as detection of phosphorylated H2AX, a sensitive indicator of DNA DSBs. Immuno-hybridization analysis revealed that the cleavage of procaspase-3 and DNA-PKcs occurred concurrently with bromovanin-induced apoptosis. Furthermore, phosphorylated Akt protein (Ser473), which is catalyzed by DNA-PKcs, as well as phosphorylated GSK3beta (a substrate of activated Akt), markedly decreased in bromovanin-treated Jurkat cells, suggesting that bromovanin leads to inactivation of Akt pathway via cleaving DNA-PKcs. These multiple effects, associated with the regimen of cancer therapeutic strategies, make bromovanin very appealing for future development as a novel anticancer drug.