Understanding a mechanism of incomplete penetrance of human tumor suppressor gene PTEN by adaptive evolution of c. elegance

Phosphatase and tensin homolog (PTEN) is a tumor suppressor gene that`s frequently deleted or mutated in several human cancers, with medium to high penetrance. In this work, we focused on the Caenorhabditis elegans ortholog of the human PTEN, daf-18. Previous studies showed that human PTEN can functionally replace DAF-18 in C. elegans, suggesting that human PTEN and DAF-18 are functionally similar and that the regulation of PTEN is highly conserved in C. elegans. This makes C.elegans an excellent choice as a model organism, as it has both cellular complexity and conservation of disease pathways while being much simpler than other animal models. Despite many types of diseases manifesting incomplete penetrance, its mechanism isn`t clear. Our hypothesis is 102 that employment of adaptive or enforced evolution will allow us to find an alternative pathway or point mutation which will allow c.elegans to overcome the depletion of daf-18. According to previous studies; there is about 70% penetrance after starvation of 72 hours. The worms were starved in every generation. We’ve started to see a change in penetrance after only two generations, and at about generation 45, there was a decrease of 50% in penetrance. We plan to keep the evolutionary process until the penetrance will decrease the wt phenotype of about 5 %. Since the change was very fast we hypothesize some epigenetic modifications involved. To further study the mechanism, we plan to sequence both DNA and RNA from the different generations, and also perform an EMS screen as an enforced version of evolution. The understanding of incomplete penetrance of PTEN, and later other oncogenes, will enable to distinguish between mutation carriers. It will be possible to eliminate unnecessary suffering from those who are not at risk and to pay more attention to those who are at high risk.