|Goodman, Cynthia - Cindy|
Submitted to: Congress on In Vitro Biology
Publication Type: Abstract Only
Publication Acceptance Date: 2/27/2006
Publication Date: 6/1/2006
Citation: Smagghe, G., Mosallanejad, H., Decombel, L., Goodman, C.L., Soin, T. 2006. Validation analysis of an ecdysteroid receptor agonist assay using intact cultured lepidoptera cells [abstract]. Congress on In Vitro Biology 42:33A.
Technical Abstract: In this study we report on the ecdysteroid-responsiveness of the insect cell line Se4 (BCIRL/AMCY-SeE-CLG4) from embryos of the beet armyworm, Spodoptera exigua (Lepidoptera: Noctuidae). The cells express an ecdysteroid receptor (EcR) activity as indicated by their response to the insect molting hormone 20-hydroxyecdysone (20E). The effect of this hormone includes a 50% inhibition of cell proliferation with the addition of ~1 µM, and morphological changes characteristic of this hormone (i.e., cell aggregation and process formation). With bisacylhydrazine tebufenozide, these typical effects were also induced, leading to the conclusion that this non-ecdysteroid compound displayed a true EcR agonist activity. Moreover, a competition binding experiment with [3H]-ponasterone A demonstrated that tebufenozide showed a similar affinity as 20E, with 50% competition for EcR binding at ~1 µM. The presence of the EcR in the Se4 cells was also confirmed using the monoclonal antibody 9B9; with the molecular weight of the EcR being around 57 kDa. In another series of experiments, three analogues of tebufenozide were tested against Se4 cells and also against beet armywom last instar (5th) larvae. These results demonstrated a good correlation between in vitro cellular proliferation inhibition and in vivo larvicidal toxicity. As determined in the last decade, N-tert-N-dibenzoylhydrazine and its derivatives are known to be non-steroidal EcR agonists that possess insecticidal activity; the method that we describe here with insect cell cultures allows for the screening of novel insecticidal compounds based on the interaction between the 20E hormone and its receptor EcR.