Global cancer statistics. of treatments, but was delayed significantly in the paclitaxel and momelotinib treated group compared to other treatment groups. Daily oral gavage of momelotinib after termination of paclitaxel treatment showed sustained inhibition of tumor growth and a prolonged disease-free survival period in 50% of the mice. The other 50% of mice that developed tumors with ongoing momelotinib treatment also showed significantly increased survival benefit and a smaller tumor burden. These preliminary findings may have a profound clinical impact in developing an effective momelotinib-based maintenance-therapy in ovarian malignancy patients’ post-chemotherapy treatment. chemotherapy-treated ovarian malignancy cells in nude mice resulted in the generation of a larger tumor burden with increased tumor staining of CSC-like cells compared to control untreated cells [3]. Nonetheless, treatment with a combination of chemotherapy and momelotinib (a potent ATP-competitive inhibitor of JAK1/2) substantially suppressed CSC-like cells and tumor burden in mice when these treated-cells were injected in mice [20]. In order to determine the pharmacological and toxicological parameters of chemotherapy and momelotinib treatment and in an mouse model. The main objective was to evaluate the effect of treatment with momelotinib in combination with paclitaxel around the tumor burden, peritoneal dissemination and disease-free remission period in a mouse model. Two ovarian malignancy cell lines representative of high-grade serous (HEY) and obvious cell (TOV21G) ovarian carcinomas were chosen to determine the effect of paclitaxel with or without momelotinib. The HEY cell collection was further examined in an mouse model to determine the effect of paclitaxel with or without momelotinib. This proof of concept study demonstrates that the use of daily oral dosing of momelotinib as a maintenance therapy after chemotherapy treatment not only prolongs the disease-free remission period but also inhibits the peritoneal dissemination in a mouse model of ovarian malignancy. The findings in this study therefore, warrant future clinical trials for comprehensive evaluation of momelotinib for the better management of ovarian malignancy patients. RESULTS The addition of momelotinib suppressed paclitaxel-induced JAK2/STAT3 pathway activation in ovarian malignancy cell lines In this study, we explored the activation of JAK2/STAT3 pathway in serous HEY and obvious cell carcinoma TOV21G cell lines by Western Blot and immunofluorescence in response to the concentration of paclitaxel GDC-0941 (Pictilisib) which inhibited cell growth by 50% (GI50) (HEY: 0.05ng/mL, TOV21G: 0.01ng/mL). HEY cell collection demonstrated the highest expression of phosphorylated-JAK2 (P-JAK2) following a 6 hour treatment (Figures ?(Figures11 and 2, A-C), while phosphorylated-STAT3 (P-STAT3) peaked following a 24 hour treatment (Figures ?(Figures11 and 2, D-F). For TOV21G cell collection, P-JAK2 and P-STAT3 expression began to peak following 24 hours of paclitaxel treatment (Supplementary Figures 1 and 2, A-F). In both HEY and TOV21G cells, P-JAK2 and P-STAT3 proteins were also observed in the nucleus GDC-0941 (Pictilisib) of cells upon activation by paclitaxel (Physique ?(Physique2,2, Supplementary Physique 2). These were mostly seen at 6 and 24 hours paclitaxel-treated Rabbit Polyclonal to Shc (phospho-Tyr349) samples, but were less prominent in 72 hour samples (Physique ?(Physique2,2, Supplementary Physique 2). The expression of total (T)-JAK2 and total (T)-STAT3 remained unchanged within 72 hours in response to paclitaxel treatment by immunofluorescence. However, Western blots showed massive down regulation of T-JAK2 and T-STAT3 expression at 72 hours-in HEY cells (Physique 1A and 1D). In TOV21G cells, no switch in the expression of total JAK2 and STAT3 was observed by Western blots or immunofluorescence. Open in a separate window Physique 1 JAK2 and STAT3 activation in HEY cells in response to paclitaxel treatment by Western blot(A and D) Total cell lysates of untreated and cells treated with 0.05g/mL of paclitaxel following 6, 24 and 72 hours of paclitaxel treatment were prepared and subjected to Western blot analysis using antibodies specific for P- GDC-0941 (Pictilisib) or T-JAK2 and P- or T-STAT3. Total protein weight was determined by stripping and re-probing the membranes with GAPDH. Images are representative of four impartial cell lysate samples. Densitometric analyses of (B-C) P-JAK2 and T-JAK2; (E-F) P-STAT3 and T-STAT3 protein expression were determined by using Image J. The values represent the relative mean band intensity normalized to GAPDH loading control SEM of four impartial experiments. Parametric one-way ANOVA with Tukey’s post-test was.