Zoptarelin Doxorubicin

Uveal melanoma (UM) is the most common malignant tumor of the eye. Recently, we have established that 46% of UM specimens express LHRH receptors. This finding supports the idea of a LHRH receptor-targeted therapy of UM patients. Cytotoxic analog of LHRH, AEZS-108 exhibits effective anti-cancer activity in LHRH-receptor positive cancers. AEZS-108 is a hybrid molecule, composed of a synthetic peptide carrier and the cytotoxic doxorubicin (DOX). In the present study, we investigated AEZS-108 induced cytotoxicity and the altered mRNA expression profile of regulatory factors related to angiogenesis and metastasis in LHRH receptor positive OCM3 cells. Our results show that AEZS-108 upregulates the expression of MASPIN/SERPINB5 tumor suppressor gene, which is downregulated in normal uvea and UM specimens independently from the LHRH receptor-ligand interaction. AEZS-108 also substantially downregulates hypoxia-inducible factor 1 alpha (HIF1A) expression. In order to investigate the mechanism of the induction of MASPIN by AEZS-108, OCM3 cells were treated with free DOX, D-Lys⁶ LHRH analog, or AEZS-108. qRT- PCR analysis revealed in OCM3 cells that AEZS-108 is a more potent inducer of MASPIN than free DOX. In conclusion, we show for the first time that AEZS-108 has a major impact in the regulation of angiogenesis thus plays a potential role in tumor suppression. Taken together, our results support the development of novel therapeutic strategies for UM focusing on LHRH receptors.

A characteristic of cancer cells including triple‐negative breast cancers (TNBC) is an increased aerobic glycolysis for ATP production representing a selective therapeutic target. More than 70% of TNBC express gonadotropin‐releasing hormone receptors (GnRH‐R). These receptors can be used for targeted chemotherapy with cytotoxic GnRH agonists such as Zoptarelin Doxorubicin, in which doxorubicin is covalently linked to [D‐Lys6]GnRH. In this study, we have analyzed whether inhibition of aerobic glycolysis can enhance the antitumor efficacy of GnRH‐R‐targeted chemotherapy using Zoptarelin Doxorubicin.

Triple‐negative breast cancers cell lines MDA‐MB‐231 and HCC1806 were treated with Zoptarelin Doxorubicin, glycolysis inhibitor 2‐deoxy‐D‐glucose (2DG) or the combination of both agents. Cell viability was measured using Alamar blue. Induction of apoptosis was quantified by measurement of loss of mitochondrial membrane potential. In vivo experiments were performed using nude mice bearing xenografted MDA‐MB‐231 tumors.

Treatment of TNBC cells with Zoptarelin Doxorubicin or with 2DG resulted in a significant decrease of cell viability and a significant increase of apoptosis. Treatment with Zoptarelin Doxorubicin in combination with 2DG resulted in significantly reduced viability and enhanced apoptosis compared with single‐agent treatments. Combinational index (CI) analysis revealed the co‐treatment effect as a synergistic. The antitumor effects of Zoptarelin Doxorubicin or 2DG were confirmed in nude mice. The tumor reducing effects of Zoptarelin Doxorubicin were enhanced by combination with 2DG.

The glycolytic phenotype of TNBC can be used to improve antitumor therapies. Co‐treatment of Zoptarelin Doxorubicin with glycolysis inhibitor 2DG might be a suitable therapeutic option for GnRH receptor‐positive TNBC.