Using Caenorhabditis Elegans To Screen Podophyllotoxin Derivatives For Down-regulation Ras/MAPK Pathway Gain-of-function

Podophyllotoxin derivatives i.e. etoposide are important drugs in clinic, they show excellent antitumor activity. However, their therapeutic use is often hindered by problems such as strong side effects and easily producing drug-resistant. So, a series of compounds have been synthesized to find the new alternatives. This paper use Caenorhabditis elegans (C. elegans) to screen the 10 podophyllotoxin derivatives by chemical synthesis in our laboratory for down-regulation Ras/MAPK pathway gain-of-function. It is aimed to get potential compound candidates having good anti-ras oncogene activity and low toxicity.Podophyllotoxin derivatives have poor water solubility. After adjusting the gradient of vehicle according to Etoposide for Injection, a (1.0%), b (20g/L), c (0.2%), d (1.6%) were found to be available and not interfere with the anti-ras oncogene activity evaluation on podophyllotoxin derivatives.Our results showed that podophyllotoxin derivatives Etoposide for Injection can significantly down-regulate Ras/MAPK pathway gain-of-function. Secondly, using C. elegans to test the 10 podophyllotoxin derivatives and Etoposide for Injection was used as positive control. 400μM p-07 and 1000μM p-10 were proved to have similar anti-ras oncogene activity and could significantly down-regulate Ras/MAPK pathway gain-of-function.The toxicity of the compounds p-07, p-10 and Etoposide for Injection were also evaluated by analyzing the true vulva position, length, width and developmental degree of C. elegans. The results showed that Etoposide for Injection can affect on the true vulva position of C. elegans, thus cause abnormal individuals. p-07 can not only affect on the true vulva position but also make nematode growth retardation. p-10 can lead shorter body length, narrower body width and slow development.Finally, the anti-ras oncogene activity of p-07, p-10 is validated by observing inhibition topoismeraseⅡactivity of the two compounds and Etoposide for Injection in vitro. The results showed that p-07 and p-10, similar to Etoposide for Injection inhibit the activity of topoismeraseⅡ.In conclusion, the activity test in vivo of Etoposide for Injection shows that using C. elegans to screen posophyllotoxin derivatives for down-regulation Ras/MAPK pathway is feasible. In contrast to Etoposide for Injection, p-07 and p-10 have similar anti-ras oncogene activity both in vitro and in vivo. However, they showed toxic, especially to the development of C. elegans. In addition, the structure-activity relationship of podophyllotoxin derivatives showed modification in the D-ring and de-saturation at C-4 could benefit for their activity.