Uterine serous cancer (USC) is aggressive, and the majority of recurrent cases are chemoresistant. Because the receptor tyrosine kinase AXL promotes invasion and metastasis of USC and is implicated in chemoresistance in other cancers, we assessed the role of AXL in paclitaxel resistance in USC, determined the mechanism of action, and sought to restore chemosensitivity by inhibiting AXL in vitro and in vivo. We used small hairpin RNAs and BGB324 to knock down and inhibit AXL. We assessed sensitivity of USC cell lines to paclitaxel and measured paclitaxel intracellular accumulation in vitro in the presence or absence of AXL. We also examined the role of the epithelial-mesenchymal transition in AXL-mediated paclitaxel resistance. Finally, we treated USC xenografts with paclitaxel, BGB324, or paclitaxel plus BGB324 and monitored tumor burden. AXL expression was higher in chemoresistant USC patient tumors and cell lines than in chemosensitive tumors and cell lines. Knockdown or inhibition of AXL increased sensitivity of USC cell lines to paclitaxel in vitro and increased cellular accumulation of paclitaxel. AXL promoted chemoresistance even in cells that underwent the epithelial-mesenchymal transition in vitro. Finally, in vivo studies of combination treatment with BGB324 and paclitaxel showed a greater than 51% decrease in tumor volume after 2 weeks of treatment when compared to no treatment or single agent treatments (P<0.001). Our results show that AXL expression mediates chemoresistance independent of EMT and prevents accumulation of paclitaxel. This study supports the continued investigation of AXL as a clinical target, particularly in chemoresistant USC.

Ovarian cancer, one of the deadliest malignancies in female cancer patients, is characterized by recurrence and poor response to cytotoxic chemotherapies. Fewer than 30% of patients with resistant disease will respond to additional chemotherapy treatments. This study aims to determine whether and how inhibition of the receptor tyrosine kinase AXL can restore sensitivity to first-line platinum and taxane therapy in ovarian cancer. AXL staining was quantified in a patient tissue microarray and correlated with chemoresponse of patients. We used small hairpin RNAs to knock down AXL expression and the small-molecule inhibitor BGB324 to inhibit AXL and assessed sensitivity of cell lines and primary patientderived cells to chemotherapy. We quantified platinum accumulation by inductivity-coupled plasma phase mass spectrometry. Finally, we treated chemoresistant patient-derived xenografts with chemotherapy, BGB324, or chemotherapy plus BGB324 and monitored tumor burden. AXL expression was higher in chemoresistant patient tumors and cell lines than in chemosensitive tumors and cell lines. AXL staining significantly predicted chemoresponse. Knockdown and inhibition of AXL dose-dependently improved response to paclitaxel and carboplatin in both cell lines and primary cells. AXL inhibition increased platinum accumulation by 2-fold (*, P < 0.05). In vivo studies indicated that AXL inhibition enhanced the ability of chemotherapy to prevent tumor growth (****, P < 0.0001). AXL contributes to platinum and taxane resistance in ovarian cancer, and inhibition of AXL improves chemoresponse and accumulation of chemotherapy drugs. This study supports continued investigation into AXL as a clinical target.

How can we provide fertile ground for students to simultaneously explore a breadth of foundational knowledge, develop cross-disciplinary problem-solving skills, gain resiliency, and learn to work as a member of a team? One way is to integrate original research in the context of an undergraduate biochemistry course. In this Community Page, we discuss the development and execution of an interdisciplinary and cross-departmental undergraduate biochemistry laboratory course. We present a template for how a similar course can be replicated at other institutions and provide pedagogical and research results from a sample module in which we challenged our students to study the binding interface between 2 important biosynthetic proteins. Finally, we address the community and invite others to join us in making a larger impact on undergraduate education and the field of biochemistry by coordinating efforts to integrate research and teaching across campuses.

Ovarian and uterine serous cancers are extremely lethal diseases that often present at an advanced stage. The late-stage diagnosis of these patients results in the metastasis of their cancers throughout the peritoneal cavity leading to death. Improving survival for these patients will require identifying therapeutic targets, strategies to target them, and means to deliver therapies to the tumors. One therapeutic target is the protein AXL, which has been shown to be involved in metastasis in both ovarian and uterine cancer. An effective way to target AXL is to silence its expression with small interfering RNA (siRNA). We investigate the ability of the novel siRNA delivery platform, p5RHH, to deliver anti-AXL siRNA (siAXL) to tumor cells both in vitro and in vivo as well as examine the phenotypic effects of this siRNA interference. First, we present in vitro assays showing p5RHH-siAXL treatment reduces invasion and migration ability of ovarian and uterine cancer cells. Second, we show p5RHH nanoparticles target to tumor cells in vivo. Finally, we demonstrate p5RHH-siAXL treatment reduces metastasis in a uterine cancer mouse xenograft model, without causing an obvious toxicity. Collectively, these findings suggest that this novel therapy shows promise in the treatment of ovarian and uterine cancer patients.

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