Inhibition of angiogenesis and improvement of the anti-angiogenic activity of paclitaxel by three insect sex pheromones in chicken chorioallantoic membrane

Background: Insect sex pheromones contain long chain polyunsaturated fatty acids. Some types of unsaturated fatty acids have been showed anticancer effects. Angiogenesis is considered as a fundamental process in cancer growth and metastasis. Angiogenesis inhibitory effect of three insect-free pheromones alone and the incremental anti-angiogenic effect of each of them with paclitaxel were evaluated on chorioallantoic membrane (CAM) of chick in the current experimental study.

Methods: Ninety fertilized eggs of Ross race were arranged into 9 groups as follows: control, dexamethasone, paclitaxel, pheromones of currant borer (Synanthedon tipuliformis); leopard moth (Zeuzera pyrina L.) and pistachio twig borer (Kermania pistaciella)-alone, and each sex pheromones plus paclitaxel. On day 8 of chick embryo incubation, 50 µl of each compound were applied to CAMs, and their effects were evaluated on day 9.

Results: Compared with controls, application of each of the pheromones alone is equally effective in reducing vessel length and branching points by 88% and 71%, respectively. Angiogenesis was suppressed (82%) by paclitaxel and stimulated (20%) by dexamethasone. Inhibitory effect of paclitaxel on vascular branching points was further increased (7%) after combination treatment with each of three pheromones. Pheromones of Z. pyrina and K. pistaciella were able to enhance (7%) antiangiogenic effect of paclitaxel.

Conclusion: The direct anti-angiogenic effects of these insect pheromones and the incremental anti-angiogenic effect of each of them with paclitaxel. This antiangiogenic effect seems independent from anti-inflammatory mechanisms. Therefore, we suggest that the effect of these pheromones with paclitaxel be studied on patients with paclitaxel-resistant tumors.