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Miami, FL, United States

Seitz S.,University of Regensburg | Buchholz S.,University of Regensburg | Schally A.V.,University of Miami | Weber F.,University of Regensburg | And 10 more authors.
BMC Cancer | Year: 2015

Background: Triple negative breast cancer (TNBC) is a distinct subtype of breast cancer burdened with a dismal prognosis due to the lack of effective therapeutic agents. Receptors for LHRH (luteinizing hormone-releasing hormone) can be successfully targeted with AEZS-108 [AN-152], an analog of LHRH conjugated to doxorubicin. Our study evaluates the presence of this target LHRH receptor in human specimens of TNBC and investigates the efficacy and toxicity of AEZS-108 in vivo. We also studied in vitro activity of AEZS-125, a new LHRH analog conjugated with the highly potent natural compound, Disorazol Z. Methods: 69 human surgical specimens of TNBC were investigated for LHRH-R expression by immunohistochemistry. Expression of LHRH-R in two TNBC cell lines was evaluated by real time RT-PCR. Cytotoxicity of AEZS-125 was evaluated by Cell Titer Blue cytoxicity assay. LHRH- receptor expression was silenced with an siRNA in both cell lines. For the in vivo experiments an athymic nude mice model xenotransplanted with the cell lines, MDA-MB-231 and HCC 1806, was used. The animals were randomised to three groups receiving solvent only (d 1, 7, 14, i.v.) for control, AEZS-108 (d 1, 7, 14, i.v.) or doxorubicin at an equimolar dose (d 1, 7, 14, i.v.). Results: In human clinical specimens of TNBC, expression of the LHRH-receptor was present in 49% (n = 69). Conclusion: The current study confirms that LHRH-receptors are expressed by a significant proportion of TNBC and can be successfully used as homing sites for cytotoxic analogs of LHRH, such as AEZS-108 and AEZS-125. © 2014 Seitz et al.; licensee BioMed Central Ltd.

Hohla F.,Oncologic Center | Hohla F.,Paracelsus Medical University | Winder T.,University of Zurich | Greil R.,Oncologic Center | And 6 more authors.
World Journal of Gastroenterology | Year: 2014

The introduction of new cytotoxic substances as well as agents that target vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) signaling has improved clinical outcome of patients with metastatic colorectal cancer (mCRC). In this review we summarize the most relevant clinical data on VEGF and EGFR targeting regimens in mCRC. The effects of available treatment strategies for mCRC are often temporary, with resistance and disease progression developing in most patients. Thus, new treatment strategies are urgently needed. Some GI peptides including gastrin and gastrin releasing peptide, certain growth factors such as insulin-like growth factor-I and II and neuropeptides such as growth hormone releasing hormone (GHRH) are implicated in the growth of CRC. Experimental investigations in CRC with antagonistic analogs of bombesin/gastrin-releasing peptide, GHRH, and with cytotoxic peptides that can be targeted to peptide receptors on tumors, are summarized in the second part of the review. © 2014 Baishideng Publishing Group Inc. All rights reserved.

Rick F.G.,Polypeptide and Cancer Institute | Block N.L.,University of Miami | Schally A.V.,University of Miami
OncoTargets and Therapy | Year: 2013

Androgen deprivation therapy remains the mainstay of medical treatment for advanced prostate cancer. Commonly, this is achieved with medical androgen deprivation rather than surgical intervention as the permanence and psychological effects of the latter are unacceptable for most patients. Degarelix is a third generation antagonist of luteinizing hormone-releasing hormone (LHRH, also termed gonadotropin-releasing hormone) for the first-line treatment of androgen-dependent advanced prostate cancer. Degarelix acts directly on the pituitary receptors for LHRH, blocking the action of endogenous LHRH. The use of degarelix eliminates the initial undesirable surge in gonadotropin and testosterone levels, which is produced by agonists of LHRH. Degarelix is the most comprehensively studied and widely available LHRH antagonist worldwide. Clinical trials have demonstrated that degarelix has a long-term efficacy similar to the LHRH agonist leuprolide in achieving testosterone suppression in patients with prostate cancer. Degarelix, however, produces a faster suppression of testosterone and prostate-specific antigen (PSA), with no testosterone surges or microsurges, and thus prevents the risk of clinical flare in advanced disease. Recent clinical trials demonstrated that treatment with degarelix results in improved disease control when compared with an LHRH agonist in terms of superior PSA progression-free survival, suggesting that degarelix likely delays progression to castration-resistant disease and has a more significant impact on bone serum alkaline phosphatase and follicle-stimulating hormone. Degarelix is usually well tolerated, with limited toxicity and no evidence of systemic allergic reactions in clinical studies. Degarelix thus represents an important addition to the hormonal armamentarium for therapy of advanced androgen-dependent prostate cancer. 2013 Rick et al, publisher and licensee Dove Medical Press Ltd.

Kiaris H.,National and Kapodistrian University of Athens | Chatzistamou I.,National and Kapodistrian University of Athens | Papavassiliou A.G.,National and Kapodistrian University of Athens | Schally A.V.,Polypeptide and Cancer Institute | Schally A.V.,University of Miami
Trends in Endocrinology and Metabolism | Year: 2011

Growth hormone-releasing hormone (GHRH) is mostly thought to act by stimulating the production and release of growth hormone from the pituitary. However, this neuropeptide emerges as a rather pleiotropic hormone in view of the identification of various extrapituitary sources for GHRH production, as well as the demonstration of a direct action of GHRH on several tissues other than the pituitary. Non-pituitary GHRH has a wide spectrum of activity, exemplified by its ability to modulate cell proliferation, especially in malignant tissues, to regulate differentiation of some cell types, and to promote healing of skin wounds. These findings extend the role of GHRH and its analogs beyond its accepted regulation of somatotropic activity and indicate new possibilities for therapeutic intervention. © 2011 Elsevier Ltd.

Hohla F.,University of Salzburg | Hohla F.,Polypeptide and Cancer Institute | Hohla F.,University of Miami | Schally A.V.,Polypeptide and Cancer Institute | Schally A.V.,University of Miami
Cell Cycle | Year: 2010

Gastrin-releasing peptide (GRP), the mammalian bombesin (BN), appears to be involved in the growth of several neoplasms. BN/GRP receptors (BN/GRP-Rs) are expressed in a variety of cancer cells and have limited distribution in normal human tissue. Thus inhibition of BN/GRP-Rs represents an attractive target for pharmacological treatment of some human malignancies. This review will focus on intracellular signaling pathways which have been characterized to mediate BN/GRP-dependent receptor biological effects as well as on various approaches to target BN/GRP-Rs for therapeutic and diagnostic interventions in human malignancies. © 2010 Landes Bioscience.

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