While ovarian cancer (OC) is relatively rare, it remains one of the most fatal cancers. Lack of robust screening methods for eOC lead to detection of most cases at advanced stages, and most patients relapse following initial treatment. Areas covered: This review summarizes epidemiology and treatment patterns of epithelial ovarian cancer (eOC). MEDLINE, EMBASE, conference proceedings, and the Cochrane Library were searched using key terms and Medical Subject Headings for ovarian cancer, treatment patterns, and epidemiology to identify articles published from 2005-2015. Expert commentary: To improve early detection, future studies should focus on the identification of biomarkers that can detect asymptomatic disease. Following diagnosis and eventual relapse, response to first-line platinum appears to guide physicians' choice of subsequent therapies, but we do not understand what patients ultimately receive or its relationship to categories of response to first-line platinum. Improved understanding of later-line treatment patterns, by initial response to platinum, could correlate with overall outcomes among relapsed patients and promote development of more effective treatment guidelines. Novel treatment approaches, such as immunotherapies, would fulfill a need for an effective strategy against advanced stages of OC that results in fewer toxic side effects.
SUMMARYThe establishment of pregnancy requires an intimate physical interaction and a molecular dialogue between the conceptus and the maternal reproductive tract that commences at implantation and continues until the placenta is formed and fully functional. Failure of the regulatory processes that ensure the fidelity of this relationship can precipitate a catastrophic pregnancy loss. One of the earliest identified molecular mediators of blastocyst implantation is heparin-binding epidermal growth factor (EGF)-like growth factor (HBEGF), which signals between the endometrium and implanting trophoblast cells to synchronize their corresponding developmental programs. HBEGF expression by trophoblast cells of the developing placenta appears to regulate extravillous differentiation and provide cytoprotection in a sometimes-hostile environment. This versatile member of the EGF signaling system will be examined in light of its associations with key events during early pregnancy.
Heparin-binding EGF-like growth factor (HBEGF) is expressed by trophoblast cells throughout gestation. First-trimester cytotrophoblast cells are protected from hypoxia-induced apoptosis because of the accumulation of HBEGF through a posttranscriptional autocrine mechanism. Exogenous application of HBEGF is cytoprotective in a hypoxia/reoxygenation (H/R) injury model and initiates trophoblast extravillous differentiation to an invasive phenotype. The downstream signaling pathways induced by HBEGF that mediate these various cellular activities were identified using two human first-trimester cytotrophoblast cell lines, HTR-8/SVneo and SW.71, with similar results. Recombinant HBEGF (1 nM) induced transient phosphorylation of MAPK3/1 (ERK), MAPK14 (p38), and AKT within 15 min and JNK after 1-2 h. To determine which downstream pathways regulate the various functions of HBEGF, cells were treated with specific inhibitors of the ERK upstream regulator MEK (U0126), the AKT upstream regulator phosphoinositide-3 (PI3)-kinase (LY294002), MAPK14 (SB203580), and JNK (SP600125), as well as with inactive structural analogues. Only SB203580 specifically prevented HBEGF-mediated rescue during H/R, while each inhibitor attenuated HBEGF-stimulated cell migration. Accumulation of HBEGF at reduced oxygen was blocked only by a combination of U0126, SB203580, and SP600125. We conclude that HBEGF advances trophoblast extravillous differentiation through coordinate activation of PI3 kinase, ERK, MAPK14, and JNK, while only MAPK14 is required for its antiapoptotic activity. Additionally, hypoxia induces an autocrine increase in HBEGF protein levels through MAPK14, JNK or ERK. These experiments reveal a complexity of the intracellular signaling circuitry that regulates trophoblast functions critical for implantation and placentation.
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