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A Disintegrin and Metalloprotease 17 (ADAM17) and its downstream signaling in chemotherapeutic resistance of ovarian cancerAcknowledgement: The AGO-TraFo is grateful to the German Cancer Society (Deutsche Krebsgesellschaft e.V.) for their financial support of the 10th scientific symposium of the AGO-TraFo.
26 November 2018 (online)
Resistance to chemotherapeutic treatment is a major problem during ovarian cancer treatment. A Disintegrin and Metalloprotease 17 (ADAM17) is highly expressed in ovarian cancer and proteolytically releases a variety of growth factors including amphiregulin (AREG) and heparin-binding EGF-like growth factor (HB-EGF). Consequently, ADAM17 regulates activation of epidermal growth factor receptor (EGFR) and downstream signaling pathways i.e. extracellular signal-regulated kinases (ERK) that are involved in cell survival, tumor progression and metastasis. Here, we investigate the role of ADAM17 and its regulated signaling pathways as a potential mechanism of chemotherapy resistance.
Ovarian cancer cell lines and primary patient derived cells were cultured in absence and presence of cisplatin. In parallel different metalloprotease inhibitors, an antibody to the EGFR (Cetuximab) and the ERK inhibitor SCH772984 were used.
EGFR and ERK phosphorylation was investigated by immunoblotting and cell viability was measured by a fluorogenic cell viability assay. Cell death was quantified by flow cytometry and a caspase-3/7 activity assay. To measure ADAM17-activity, AREG concentrations in culture supernatants were measured as a surrogate marker by Enzyme-linked Immunosorbent Assay (ELISA).
Chemotherapeutic treatment with cisplatin led to an increased AREG shedding in a dose-dependent manner in most ovarian cancer cell lines and patient derived cells. This effect could be blocked, using the metalloprotease inhibitor GW280264X (GW, ADAM10- and ADAM17-selective) but not GI254023X (GI, ADAM10-selective).
Moreover, cisplatin treatment induced EGFR and ERK-phosphorylation in Igrov-1 and Skov-3 cells. Inhibition of ADAM17 reduced cell viability and sensitized ovarian cancer cells to cisplatin treatment.
Treatment of Igrov-1 cells with either cetuximab (EGFR inhibition) or SCH772984 (Erk inhibition) led to a sensitization to cisplatin treatment, likewise.
Apart from their general relevance in tumor progression, ADAM17 and its downstream signaling (EGFR and ERK) play an important role in regulation of chemotherapeutic resistance. Blocking of these pathways in parallel to chemotherapy could reveal a potential strategy to overcome resistance mechanisms.