Chemotherapy resistance is a major challenge in ovarian cancer (OvCa). Thus, novel treatment combinations are highly warranted. However, many promising drug candidates tested in two-dimensional (2D) cell culture have not proved successful in the clinic. For this reason, we analyzed our drug combination not only in monolayers but also in three-dimensional (3D) tumor spheroids. One potential therapeutic target for OvCa is A disintegrin and metalloprotease 17 (ADAM17). ADAM17 can be activated by chemotherapeutics, which leads to enhanced tumor growth due to concomitant substrate cleavage. Therefore, blocking ADAM17 during chemotherapy may overcome resistance. Here, we tested the effect of the ADAM17 inhibitor GW280264X in combination with cisplatin on ovarian cancer cells in 2D and 3D. In 2D, the effect on five cell lines was analyzed with two readouts. Three of these cell lines formed dense aggregates or spheroids (HEY, SKOV-3, and OVCAR-8) in 3D and the treatment effect was analyzed with a multicontent readout (cytotoxicity, viability, and caspase3/7 activation). We tested the combined therapy on tumor spheroids derived from primary patient cells. In 2D, we found a significant reduction in the half minimal (50%) inhibitory concentration (IC50) value of the combined treatment (GW280264X plus cisplatin) in comparison with cisplatin monotherapy in all five cell lines with both 2D readout assays (viability and caspase activation). In contrast, the combined treatment only showed an IC50 reduction in HEY and OVCAR-8 3D tumor spheroid models using caspase3/7 activity or CelltoxTM Green as the readout. Finally, we found an improved effect of GW280264X with cisplatin in tumor spheroids derived from patient samples. In summary, we demonstrate that ADAM17 inhibition is a promising treatment strategy in ovarian cancer.

Chemotherapeutic resistance evolves in about 70 % of ovarian cancer patients and is a major cause of death in this tumor entity. Novel approaches to overcome these therapeutic limitations are therefore highly warranted. A disintegrin and metalloprotease 17 (ADAM17) is highly expressed in ovarian cancer and required for releasing epidermal growth factor receptor (EGFR) ligands like amphiregulin (AREG). This factor has recently been detected in ascites of advanced stage ovarian cancer patients. However, it is not well understood, whether and how ADAM17 might contribute to chemo resistance of ovarian cancer.In this study, we identified ADAM17 as an essential upstream regulator of AREG release under chemotherapeutic treatment in ovarian cancer cell lines and patient derived cells. In the majority of ovarian cancer cells cisplatin treatment resulted in enhanced ADAM17 activity, as shown by an increased shedding of AREG. Moreover, both mRNA and the protein content of AREG were dose-dependently increased by cisplatin exposure. Consequently, cisplatin strongly induced phosphorylation of ADAM17-downstream mediators, the EGFR and extracellular signal-regulated kinases (ERK). Phorbol 12-myristate 13-acetate (PMA), similarly to cisplatin, mediated AREG shedding and membrane fading of surface ADAM17.Inhibition of ADAM17 with either GW280264X or the anti-ADAM17 antibody D1 (A12) as well as silencing of ADAM17 by siRNA selectively reduced AREG release. Thus, ADAM17 inhibition sensitized cancer cells to cisplatin-induced apoptosis, and significantly reduced cell viability.Based on these findings, we propose that targeting of ADAM17 in parallel to chemotherapeutic treatment suppresses survival pathways and potentially diminish evolving secondary chemo resistance mechanisms.

Ovarian cancer has the highest mortality rate among gynecological tumors. This is based on late diagnosis and the lack of early symptoms. To improve early detection, it is essential to find reliable biomarkers. The metalloprotease ADAM17 could be a potential marker, as it is highly expressed in many solid tumors, including ovarian and breast cancer. The aim of this work is to evaluate the relevance of ADAM17 as a potential diagnostic blood-based biomarker in ovarian cancer. Ovarian cancer cell lines IGROV-1 and A2780, as well as primary patient-derived tumor cells obtained from tumor tissue and ascitic fluid, were cultured to analyze ADAM17 abundance in the culture supernatant. In a translational approach, a cohort of 117 well-characterized ovarian cancer patients was assembled and ADAM17 levels in serum and corresponding ascitic fluid were determined at primary diagnosis. ADAM17 was quantified by enzyme-linked immunosorbent assay (ELISA). In the present study, ADAM17 was detected in the culture supernatant of ovarian cancer cell lines and primary cells. In addition, ADAM17 was found in serum and ascites of ovarian cancer patients. ADAM17 level was significantly increased in ovarian cancer patients compared to an age-matched control group (p < 0.0001). Importantly early FIGO I/II stages, which would not have been detected by CA-125, were associated with higher ADAM17 concentrations (p = 0.007). This is the first study proposing ADAM17 as a serum tumor marker in the setting of a gynecological tumor disease. Usage of ADAM17 in combination with CA-125 and other markers could help detect early stages of ovarian cancer.

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Epithelial ovarian cancer is the second most common malignancy of the female genital tract, with approximately 7,400 new cases annually in Germany. With 5,500 deaths per year, ovarian cancer is the leading gynecologic cause of death. Epithelial ovarian cancer is characterized by morphologic heterogeneity with 4 molecular biological subtypes (immunoreactive-like, differentiated-like, proliferative-like, mesenchymal-like) with different prognosis. Significantly improved survival is achieved by optimal debulking with no residual disease (R0). Systematic lymphonodectomy of clinical negative lymph nodes has no effect on overall survival in advanced ovarian cancer. Interval debulking in advanced ovarian cancer after three cycles of neoadjuvant chemotherapy with carboplatin/paclitaxel is controversial. Standard chemotherapy for advanced ovarian cancer consists of six cycles of carboplatin AUC5 and paclitaxel 175 mg/m 2 , in a three-week cycle. Intraperitoneal chemotherapy is not a standard therapy. Anti-hormonal therapy with an aromatase inhibitor plays a minor role in therapy of both low grade serous ovarian cancer (LGSOC) and high grade serous ovarian cancer (HGSOC). A major achievement in ovarian cancer therapy has been the results of the SOLO-1 trial, in which olaparib as a first line maintenance monotherapy resulted in an overall 70% lower risk of disease progression in patients with advanced Breast Cancer Gene (BRCA)-mutated ovarian cancer.Epithelial ovarian cancer is the second most common malignant disease of the female genital tract in Germany with approximately 7,400 new cases annually. Thus, one in 75 women will develop ovarian cancer during her lifetime. With 5,500 deaths annually, ovarian cancer is the leading gynecologic cause of death (1).Over the past 15 years, the quality of treatment for ovarian cancer has been continuously improving. Median PFS has increased from 12.7 months in 2004 to 20.7 months in 2016 in FIGO stages III and IV. Treatment at an experienced center and an optimal tumor reduction during primary surgery is not least responsible for this (2). Experience of Treatment CenterTreatment center experience plays a crucial role in ovarian cancer therapy. In 2014 Bristow et al. (6) proved that patients 3253 This article is freely accessible online.