Background: Chemoresistance to platinum-based drugs remains a major obstacle for the treatment of epithelial ovarian cancer (EOC). It is speculated that increased circulating levels of gonadotropins in postmenopausal women for the follicle-stimulating hormone (FSH), increases the risk of developing EOC. Proline-rich tyrosine kinase 2 (Pyk2), a member of the focal adhesion kinase family, may have a role in cellular FSH signalling through the extracellular signal-regulated kinase (ERK) which may also have role in DNA-damage induced apoptosis from platinum-based drugs such as cisplatin. Pyk2 has been shown to regulate p53 levels controlling both cell proliferation and survival in murine ID8 ovarian carcinoma cells2 suggesting that pyk2 regulation of p53 may promote cell survival upon cisplatin induced cell stress.

Aim: To determine a role for Pyk2 and p53 in FSH-induced ERK activation, proliferation and migration of EOC cells with platinum-based chemotherapeutics.

Methods: EOC cell lines were treated with 10-50 nM FSH for 10 min, followed by determination of ERK and phosphorylated ERK by Western blot. siRNA was used to down-regulate Pyk2 prior to stimulation with FSH. Cellular localisation of Pyk2 and p53 in response to FSH and cisplatin will be determined by immunofluorescence, and interactions between these molecules inferred by proximity ligation assays (PLA).

Results: Pyk2 protein and mRNA levels were shown to be significantly reduced at 48 and 72h following transfection with Pyk2 siRNA, compared with non-silencing controls. FSH and treatment resulted in the activation of ERK signalling. Data will be presented determining interactions between Pyk2 and p53 after treatment with either FSH or cisplatin.

Conclusions: Pyk2 likely plays an important role in determining the cellular response to increased FSH. Furthermore, interactions between Pyk2 and p53 may be important in regulation of the cellular response to FSH and DNA damage.

2 Lim St et al., J Biol Chem. 2010 Jan 15;285(3):1743-53.