High expression of wee1 is associated with malignancy in vulvar squamous cell carcinoma patients

BACKGROUND: Vulvar squamous cell carcinoma is a cancer form with increasing incidence rate and few treatment options. Wee1 is a central regulator of the G2/M DNA-damage checkpoint, and has in previous studies been described as a prognostic biomarker and a potential target for therapy in other cancer forms. METHODS: In the present study we analyzed the expression of Wee1 in a panel of 297 vulvar tumors by immunohistochemistry. Furthermore, siRNA transfections were carried out in two vulvar cancer cell lines (SW-954 and CAL-39) in order to study the effect on cell cycle distribution (flow cytometry) and proteins (western blot) involved in DNA damage response and apoptosis. RESULTS: Wee1 kinase is increased in vulvar squamous cell carcinomas, as compared to expression in normal epithelium, and a high Wee1 expression is associated with markers of malignancy, such as lymph node metastasis and poor differentiation. Our in vitro results showed that siRNA mediated Wee1 silencing only led to a modest reduction in viability, when examined in vulvar cancer cell lines. Nonetheless, a marked increase in DNA damages, as assessed by augmented levels of γ-H2AX, was observed in both cell lines in the absence of Wee1. CONCLUSIONS: Our results suggest that Wee1 may be involved in the progression of vulvar carcinomas. Based on our in vitro results, Wee1 is unlikely to function as a target for mono-treatment of these patients.