zibotentan and Ovarian-Neoplasms

Endothelins are a family of peptide compounds which exert regulatory control over cellular processes important for growth, survival, invasion, and angiogenesis. In particular, endothelin-1, acting primarily through the endothelin-A receptor, is implicated in the neoplastic growth of multiple tumor types. In preclinical models, endothelin antagonism inhibits tumor cell proliferation, invasiveness, and new vessel formation, as well as attenuates osteoblastic and pain-related responses to tumor. Clinical testing of an orally bioavailable endothelin antagonist has demonstrated benefit in PSA progression, markers of bone turnover, and pain in men with prostate cancer, but has not demonstrated significant improvement in survival or time to cancer progression. Although this class of drugs is promising for targeted anti-cancer therapy, their role in treatment remains to be defined by completion of future clinical trials.

Topics: Atrasentan; Bosentan; Clinical Trials as Topic; Endothelin Receptor Antagonists; Endothelin-1; Female; Humans; Male; Neoplasms; Ovarian Neoplasms; Prostatic Neoplasms; Pyrimidines; Pyrrolidines; Receptors, Endothelin; Signal Transduction; Sulfonamides

In platinum-sensitive relapsed ovarian cancer, paclitaxel plus carboplatin is a standard second-line treatment. Zibotentan (ZD4054) is an oral, specific ETA-receptor antagonist with demonstrated antitumour activity in xenograft models of human ovarian cancer.. In this Phase II, randomized, placebo-controlled study, patients with relapsed ovarian cancer sensitive to platinum-based chemotherapy received zibotentan 10mg or placebo once-daily, plus paclitaxel 175 mg/m(2) iv followed by carboplatin iv (AUC 5) on day 1 of every 3-week cycle for a maximum of eight cycles. The primary endpoint was progression-free survival (PFS), evaluated by Response Evaluation Criteria In Solid Tumours (RECIST). Secondary and exploratory endpoints included objective tumour response rate, tumour size, CA-125/RECIST progression, and safety and tolerability.. A total of 120 patients were randomized (zibotentan: n=59; placebo: n=61). Addition of zibotentan 10mg/day to carboplatin and paclitaxel did not improve PFS compared with placebo (median PFS, 7.6 versus 10.0 months, respectively; HR=1.46, [80% CI: 1.10-1.94]; P=0.0870). No improvements in any of the secondary or exploratory efficacy endpoints were observed for patients receiving zibotentan compared with placebo. Median duration of total treatment exposure was 6.7 months. Total chemotherapy dose received was lower for zibotentan-treated versus placebo-treated patients (carboplatin: -16%; paclitaxel: -14%). The most common adverse events in the zibotentan arm were anaemia, nausea, alopecia, headache and neutropenia (43-48% of patients).. Zibotentan 10mg/day plus carboplatin and paclitaxel did not result in an improvement in PFS compared with chemotherapy alone in patients with advanced ovarian cancer sensitive to platinum-based chemotherapy. No unexpected safety concerns were identified.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Carboplatin; Carcinoma, Ovarian Epithelial; Disease-Free Survival; Double-Blind Method; Drug Administration Schedule; Female; Humans; Middle Aged; Neoplasms, Glandular and Epithelial; Ovarian Neoplasms; Paclitaxel; Placebos; Pyrrolidines; Young Adult

Endothelin A receptor (ET(A)R) and epidermal growth factor receptor (EGFR) cross-talk enhances the metastatic potential of epithelial ovarian cancer (EOC) cells activating different pathways, including β-catenin signalling. Here, we evaluated β-catenin as one of ET(A)R/EGFR downstream pathway in the invasive behaviour of EOC cells and their therapeutic potential to co-target ET(A)R and EGFR.. The phosphorylation status and interactions of different proteins were analysed by immunoblotting and immunoprecipitation. Reporter activity and RT-PCR was used for evaluation of β-catenin transcriptional activity and gene expression. Functional effects were evaluated by gelatin zymography and cell invasion assays. An orthotopic model of metastatic human EOC in mice was used for in vivo studies.. In EOC cell lines, ET-1 induced Src-dependent EGFR transactivation, causing tyrosine (Y) phosphorylation of β-catenin at the residue Y654, its dissociation from E-cadherin complexes and the accumulation as an active form. This pool of Tyr-β-catenin relocalised to the nucleus promoting its transcriptional activity, and the expression of its target genes, such as MMP-2. At functional level, ET-1 and EGFR circuits enhanced protease activity and cell invasion. All these effects were significantly inhibited by the ET(A)R antagonist, zibotentan, or EGFR inhibitor, gefitinib, and are completely blocked by co-addition of both drugs. In vivo, zibotentan treatment significantly inhibited metastases, associated with reduced expression and activation of MMPs and active β-catenin, especially when combined with gefitinib.. Altogether these findings provide additional support to the potential use of ET(A)R and EGFR blockade as a new therapeutic opportunity for EOC treatment.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; beta Catenin; Cell Line, Tumor; ErbB Receptors; Female; Gefitinib; Humans; Matrix Metalloproteinases; Mice; Mice, Nude; Neoplasm Metastasis; Ovarian Neoplasms; Phosphorylation; Pyrrolidines; Quinazolines; Receptor, Endothelin A; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction

Emerging evidence suggests molecular and phenotypic association between chemoresistance and epithelial-mesenchymal transition (EMT) in cancer. Endothelin-1 (ET-1)/endothelin A receptor (ET(A)R) axis is implicated in the pathobiology of epithelial ovarian cancer (EOC) by driving tumor-promoting effects, including EMT. Here, we analyzed how ET(A)R regulates chemoresistance and EMT in EOC.. The effects of ET-1 axis on cell proliferation, drug-induced apoptosis, invasiveness, and EMT were analyzed in cultured EOC cells sensitive and resistant to cisplatinum and taxol. Tumor growth in response to ET(A)R antagonist was examined in EOC xenografts. ET(A)R expression was examined in 60 human EOC tumors by immunohistochemistry and correlated with chemoresistance and EMT.. In resistant EOC cells ET-1 and ET(A)R are upregulated, paralleled by enhanced mitogen activated protein kinase (MAPK) and Akt phosphorylation and cell proliferation. Moreover, in these cells the expression of E-cadherin transcriptional repressors, including Snail, Slug, and Twist, as well as of mesenchymal markers, such as vimentin and N-cadherin, were upregulated and linked with enhanced invasive behavior. Interestingly, ET(A)R blockade with zibotentan, a specific ET(A)R antagonist, or its silencing, downregulated Snail activity, restored drug sensitivity to cytotoxic-induced apoptosis, and inhibited the invasiveness of resistant cells. In vivo, zibotentan inhibited tumor growth of sensitive and resistant EOC xenografts, and sensitized to chemotherapy. Analysis of EOC human tissues revealed that ET(A)R is overexpressed in resistant tumors and is associated with EMT phenotype.. Our data provide the first evidence that blockade of ET(A)R-driven EMT can overcome chemoresistance and inhibit tumor progression, improving the outcome of EOC patients' treatment.

Topics: Aged; Animals; Antineoplastic Combined Chemotherapy Protocols; Blotting, Western; Cell Line, Tumor; Cisplatin; Drug Resistance, Neoplasm; Endothelin A Receptor Antagonists; Endothelin-1; Epithelial-Mesenchymal Transition; Female; Gene Expression Regulation, Neoplastic; Humans; Mice; Mice, Nude; Middle Aged; Ovarian Neoplasms; Paclitaxel; Pyrrolidines; Receptor, Endothelin A; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Treatment Outcome; Xenograft Model Antitumor Assays

In human ovarian carcinoma, the endothelin-1 (ET-1) / endothelin A receptor (ETAR) axis is overexpressed, correlating with tumor grade. Moreover, ETAR activation by ET-1 affects cell proliferation, survival, angiogenesis, and invasion. ETAR blockade with zibotentan (ZD4054), a specific ETAR antagonist, significantly inhibits ovarian cancer growth in vitro and in vivo, underscoring the relevance of this pathway as a target for cancer therapy. Since clinical trial results have defined the combination of platinum and taxane as the standard of care in the management of ovarian cancer, here we explored the therapeutic efficacy of the integration of zibotentan with cytotoxic drugs having different modes of action. We found that the combination of zibotentan with cisplatinum as well as zibotentan with paclitaxel was more effective at inhibiting ovarian cancer HEY cell proliferation induced by endogenous ET-1 than were the single agents alone. However, a significantly enhanced efficacy was observed when we combined zibotentan, cisplatinum, and paclitaxel. Accordingly, in HEY xenografts the coadministration of zibotentan with cisplatinum enhanced the efficacy of the cytotoxic drug alone in controlling tumor growth, associated with reduction in proliferation index and microvessel density. Remarkably, the combination of zibotentan with both cisplatinum and paclitaxel was very effective in inhibiting tumor growth, neovascularization, and cell proliferation, representing a preclinical endpoint to guide combination therapy in clinical trials.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Cisplatin; Drug Therapy, Combination; Endothelin A Receptor Antagonists; Female; Humans; Ki-67 Antigen; Mice; Mice, Nude; Neoplasms, Glandular and Epithelial; Neovascularization, Pathologic; Ovarian Neoplasms; Paclitaxel; Pyrrolidines; Xenograft Model Antitumor Assays

The contribution of the endothelin-1 (ET-1)/ET A receptor (ETAR) axis in tumor growth and progression is investigated in many tumor types, including ovarian carcinoma. In ovarian cancer cells, ET-1 acts as an autocrine growth factor selectively through the ETAR triggering the concomitant activation of multiple pathways. In these cells, the involvement of beta-arrestin-1 as signal transducer in ET-1-dependent signalling pathways has been recently highlighted. Because several G protein-coupled receptors have been shown to activate signalling pathways in a beta-arrestin-dependent manner, in this study we explored whether beta-arrestin-1 is involved in a distinct signalling mechanism linking the ETAR to phosphoinositide 3-kinase (PI3K)/integrin-linked kinase (ILK)/Akt in HEY ovarian cancer cells. The inhibitory effects of ZD4054 (zibotentan), a specific ETAR antagonist, in ET-1-dependent phosphorylation of ILK, Akt, and glycogen synthase kinase (GSK-3beta) demonstrated the involvement of the ETAR in these effects. By using a kinase assay, we demonstrate that beta-arrestin-1 silencing inhibits the ET-1-induced ILK activity in a time-dependent manner and downstream Akt and GSK-3beta phosphorylation. These results reveal that beta-arrestin-1 is implicated as an ETAR-transducer in the activation of ILK and Akt and in the inactivation of GSK-3beta in response to ET-1 and further support the role of beta-arrestin-1 as a multifunctional adaptor facilitating interprotein interactions critically involved in ETAR-mediated signalling that regulate invasive and metastatic behaviour of ovarian cancer.

Topics: Arrestins; beta-Arrestin 1; beta-Arrestins; Cell Line, Tumor; Endothelin A Receptor Antagonists; Endothelin-1; Enzyme Activation; Female; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Humans; Models, Biological; Ovarian Neoplasms; Phosphorylation; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; Pyrrolidines; RNA, Small Interfering; Signal Transduction

Ovarian carcinomas overexpress endothelin A receptors (ET(A)R) and epidermal growth factor (EGF) receptor (EGFR). In these cells, endothelin-1 (ET-1) triggers mitogenic and invasive signaling pathways that are in part mediated by EGFR transactivation. Combined targeting of ET(A)R, by the specific ET(A)R antagonist ZD4054, and of EGFR by the EGFR inhibitor gefitinib (IRESSA), may offer improvements in ovarian carcinoma treatment. In HEY and OVCA 433 ovarian carcinoma cells, ET-1 or EGF induced rapid activation of EGFR, p42/44 mitogen-activated protein kinase (MAPK), and AKT. ZD4054 was able to reduce the ET-1-induced EGFR transactivation. Gefitinib significantly inhibited EGF- and ET-1-induced EGFR phosphorylation, but incompletely reduced the ET-1-induced activation of downstream targets. ZD4054 plus gefitinib resulted in a greater inhibition of EGFR, MAPK, and AKT phosphorylation, indicating the critical role of these interconnected signaling proteins. ZD4054 effectively inhibited cell proliferation, invasiveness, and vascular endothelial growth factor (VEGF) secretion. Concomitantly, ZD4054 enhanced apoptosis and E-cadherin promoter activity and expression. In both cell lines, the drug combination resulted in a significant decrease in cell proliferation (65%), invasion (52%), and VEGF production (50%), accompanied by a 2-fold increase in apoptosis. The coadministration of ZD4054 enhanced the efficacy of gefitinib leading to partial (82%) or complete tumor regression on HEY ovarian carcinoma xenografts. Antitumor effects were paralleled by biochemical and immunohistologic evidence of decreased vascularization, Ki-67, matrix metalloproteinase-2 (MMP-2), VEGF, MAPK and EGFR, and enhanced E-cadherin expression. The cross-signaling between the EGFR/ET(A)R pathways provides a rationale to combine EGFR inhibitors with ET(A)R antagonists, identifying new effective therapeutic opportunities for ovarian cancer.

Topics: Animals; Antineoplastic Agents; Cadherins; Cell Line, Tumor; ErbB Receptors; Female; Gefitinib; Humans; Matrix Metalloproteinase 2; Mice; Mice, Nude; Neoplasm Invasiveness; Ovarian Neoplasms; Pyrrolidines; Quinazolines; Receptor, Endothelin A

The autocrine endothelin (ET)-1/endothelin A receptor (ET(A)R) pathway is an important regulator of several processes involved in ovarian cancer progression, and its overexpression is associated with aggressive disease. These features have led to the proposal of the ET(A)R receptor as a potential target for improving ovarian cancer treatment. In this study, we evaluated in vitro and in vivo the effects of ZD4054, an orally active antagonist that specifically binds ET(A)R, as monotherapy, and in combination with paclitaxel. In the human ovarian cancer ET(A)R-positive cell lines HEY, OVCA 433, SKOV-3, and A-2780, ZD4054 effectively inhibited the basal and ET-1-induced cell proliferation, associated with the inhibition of AKT and p42/44MAPK phosphorylation, and with increased apoptosis, through the inhibition of bcl-2 and activation of caspase-3 and poly(ADP-ribose) polymerase proteins. ZD4054 treatment also resulted in a reduction of ET(A)R-driven angiogenesis and invasive mediators, such as vascular endothelial growth factor, cyclooxygenase-1/2, and matrix metalloproteinase (MMP). The combination of ZD4054 and paclitaxel led to the potentiation of all these effects, indicating that ZD4054, by blocking the ET(A)R-dependent proliferative, invasive, and antiapoptotic signals, can enhance sensitivity to paclitaxel. In HEY ovarian cancer xenografts, ZD4054 significantly inhibited tumor growth to the same degree as paclitaxel. Furthermore, ZD4054-dependent tumor growth inhibition was associated with a reduction in proliferation index, microvessel density, and MMP-2 expression. Interestingly, the combination of ZD4054 and paclitaxel produced additive antitumor effects, with 40% of mice remaining tumor-free, supporting a rationale for the clinical use of ZD4054 as monotherapy or in combination with cytotoxic drugs.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Line, Tumor; Cell Proliferation; Drug Synergism; Endothelin A Receptor Antagonists; Female; Humans; Immunohistochemistry; Mice; Mice, Nude; Neoplasm Invasiveness; Neovascularization, Pathologic; Ovarian Neoplasms; Paclitaxel; Pyrrolidines; Xenograft Model Antitumor Assays

Endothelin-1 (ET-1) is present at high concentrations in ovarian cancer ascites and is overexpressed in primary and metastatic ovarian carcinomas. In these tumors, the presence of ET-1 correlates with tumor grade, enhanced neovascularization, and with vascular endothelial growth factor (VEGF) expression. ET-1 acts as an autocrine factor selectively through ET(A) receptor (ET(A)R), predominantly expressed in ovarian carcinoma cells resulting in increased VEGF production and VEGF-mediated angiogenic effects. Previous results demonstrated that in ovarian carcinoma cells, activation of the ET-1/ET(A)R axis promotes cell proliferation, neovascularization, and invasion, which are the principal hallmarks of tumor progression. The present study was designed to investigate the in vitro effects of trans, trans-2(4-methoxydhenyl)-4-(1-3-benzodiazol-5-yl)-1-(dibutylaminocarbonylmethyl)-pyrrolidine-3-carboxylic acid (ZD4054), an orally active specific ET(A)R antagonist, on the ET-1-induced mitogenic effect in OVCA 433 and HEY ovarian carcinoma cell lines secreting ET-1 and expressing ET(A)R and ET(B)R mRNA. We show that ET(A)R blockade by ZD4054 inhibits ET-1-induced mitogenic effects, while the ET(B)R antagonist, BQ 788, is ineffective. In conclusion, our data demonstrate that ZD4054 is capable in inhibiting the proliferative activity of ET-1, indicating that this specific ET(A)R antagonist may be a potential candidate in developing novel treatment of ovarian carcinoma.

Topics: Cell Line, Tumor; Cell Proliferation; Endothelin A Receptor Antagonists; Endothelin-1; Female; Humans; Ovarian Neoplasms; Pyrrolidines; RNA, Messenger