Dissecting the molecular link between cancer and oocyte-based infertility - a pilot study - PROJECT SUMMARY Accurate M-Phase regulation is essential for human health. M-Phase aberrations are observed in numerous disease states, with cancer and female infertility two of the best-known pathophysiologies attributed to M- Phase abnormalities. Highlighting this, dysregulation of cell cycle controls is a hallmark of cancer, and ~1% of women are subfertile/infertile due to meiotic failure. Notably, infertile females are at a higher risk of developing cancer, suggesting a causative link between the two disease states. Despite this, the source of M-Phase abnormalities and the potential molecular link between cancer and infertility remain largely unknown. Therefore, this project aims to (1) investigate the potential molecular mechanisms linking infertility and cancer and (2) develop a pipeline for testing the impact of rare variants in vivo. This proof of principle study will focus on the phosphatase, Protein Phosphatase 1 (PP1). It is widely accepted that PP1 is essential for normal M- Phase progression in mitosis and oocyte meiosis. Furthermore, alterations in PP1 is observed in numerous cancers and are associated with prognostic outcomes. However, the contribution of PP1 polymorphisms to health and disease is unclear. Humanization of S. cerevisiae is becoming an increasingly attractive approach to screen the impact of cancer-occurring polymorphisms in a high throughput manner. Glc7 (yeast PP1) can be functionally replaced by all human PP1 isoforms (α, β, and γ). Humanized Glc7 has been successfully used to screen the effect of 7 cancer-associated PP1 polymorphisms on yeast growth. However, how these PP1 variants negatively impact mammalian cells is unknown. This pilot study will develop a novel pipeline to screen potentially damaging cancer-associated polymorphisms in humanized yeast, before determining their impact on mammalian oocyte meiosis. In Aim 1, humanized yeast will be used to assess the impact of 30 cancer- associated PP1 missense variants on yeast growth and survival. Therefore, Aim 1 will uncover PP1 variants that could contribute to M-Phase-associated disease, including infertility and cancer. Aim 2 will take this a step further by elucidating the impact the most damaging PP1 variants from Aim 1 have on oocyte meiosis. Therefore, this work will begin to test the central hypothesis that PP1 polymorphisms impact female fertility and cancer susceptibility in humans. Ultimately, this work will have two outcomes: (1) It will discover new and potentially significant roles for PP1 in oocyte meiosis, and (2) it will begin to establish the molecular link between cancer and infertility, and addresses the NICDH priority of establishing fertility as a marker for human health and disease.
