sermorelin and Lung-Neoplasms

The syntheses and biological evaluation of GHRH antagonists of AVR series with high anticancer and anti-inflammatory activities are described. Compared to our previously reported GHRH antagonist 602 of MIAMI series, AVR analogs contain additional modifications at positions 0, 6, 8, 10, 11, 12, 20, 21, 29 and 30, which induce greater antitumor activities. Five of nineteen tested AVR analogs presented binding affinities to the membrane GHRH receptors on human pituitary, 2-4-fold better than MIA-602. The antineoplastic properties of these analogs were evaluated in vitro using proliferation assays and in vivo in nude mice xenografted with various human cancer cell lines including lung (NSCLC-ADC HCC827 and NSCLC H460), gastric (NCI-N87), pancreatic (PANC-1 and CFPAC-1), colorectal (HT-29), breast (MX-1), glioblastoma (U87), ovarian (SK-OV-3 and OVCAR-3) and prostatic (PC3) cancers. In vitro AVR analogs showed inhibition of cell viability equal to or greater than MIA-602. After subcutaneous administration at 5 μg/day doses, some AVR antagonists demonstrated better inhibition of tumor growth in nude mice bearing various human cancers, with analog AVR-353 inducing stronger suppression than MIA-602 in lung, gastric, pancreatic and colorectal cancers and AVR-352 in ovarian cancers and glioblastoma. Both antagonists induced greater inhibition of GH release than MIA-602 in vitro in cultured rat pituitary cells and in vivo in rats. AVR-352 also demonstrated stronger anti-inflammatory effects in lung granulomas from mice with lung inflammation. Our studies demonstrate the merit of further investigation of AVR GHRH antagonists and support their potential use for clinical therapy of human cancers and other diseases.

Topics: Animals; Anti-Inflammatory Agents; Apoptosis; Cell Line, Tumor; Female; Glioblastoma; Growth Hormone; Growth Hormone-Releasing Hormone; Humans; Lung Neoplasms; Mice; Mice, Nude; Ovarian Neoplasms; Rats; Sermorelin

Lung cancers which show increased vascularization and high microvessel density are considered highly metastatic and with poor prognosis. Growth hormone releasing hormone (GHRH) antagonists are anticancer agents without adverse events in lung cancer tumor models. In the present study we investigated the in vitro effect of GHRH antagonist, MZ-5-156, on focal adhesion kinase (FAK) activity, on the expression of MMP-2 and MMP-9 metalloproteinases, as well as on vascular endothelial growth factor (VEGF) levels in A549 non-small cell lung (NSCLC) cancer cells and H727 bronchial carcinoid cells. We demonstrate for the first time that GHRH antagonist, MZ-5-156, inhibits FAK signaling in lung cancer cells and decreases the expression of additional factors involved in angiogenesis and invasion. In contrast, GHRH itself counteracted these effects. Our study contributes to the further understanding of the processes which govern the mechanism of action of GHRH and its antagonists in cancers.

Topics: Cell Line, Tumor; Down-Regulation; Focal Adhesion Protein-Tyrosine Kinases; Gene Expression; Growth Hormone-Releasing Hormone; Humans; Lung Neoplasms; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Phosphorylation; Protein Processing, Post-Translational; Sermorelin; Vascular Endothelial Growth Factor A

AMP-activated protein kinase (AMPK) regulates cellular proliferation, growth and metabolism. Targeted activation of AMPK is considered an important therapeutic strategy for cancer treatment. To evaluate the effect of growth hormone-releasing hormone (GHRH) and its antagonist MZ-5-156 on the phosphorylation of AMPK and other related regulatory intracellular proteins we employed human non-small cell lung cancer cell line A549, which expresses GHRH receptors. Treatment of A549 cells with GHRH antagonist decreased cell proliferation and activated AMPK as well as glycogen synthase kinase (GSK)3β. Furthermore, MZ-5-156 inhibited Akt, the mammalian target of rapamycin (mTOR) and its downstream target eIF4E which controls protein synthesis and cell growth. GHRH(1-29)NH2 counteracted all these effects. HeLa human endometrial cancer cells which do not express any GHRH receptors were used as a negative control and GHRH did not induce the AMPK activation in these cells. Our results demonstrate for the first time that GHRH antagonists can regulate the AMPK metabolic pathway, which is crucial for the growth of non-small cell lung cancer and other major cancers.

Topics: AMP-Activated Protein Kinases; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Proliferation; Eukaryotic Initiation Factor-4E; Gene Expression; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Growth Hormone-Releasing Hormone; HeLa Cells; Humans; Ki-67 Antigen; Lung Neoplasms; Phosphorylation; Proto-Oncogene Proteins c-akt; Sermorelin; TOR Serine-Threonine Kinases

New therapeutic strategies are necessary to improve the treatment of lung cancer. We investigated the effects of bombesin/gastrin-releasing peptide (GRP) antagonist, RC-3940-II, and growth hormone-releasing hormone (GHRH) antagonists, MZ-J-7-114 and MZ-J-7-118, on the expression of epidermal growth factor receptor (EGFR)/HER (-2, -3, and -4) family, angiogenic factors, VEGF-A and VEGF receptors (VEGF-R1 and VEGF-R2), and the apoptotic molecules Bax and Bcl-2, in H-460 and A-549 non-small cell lung carcinomas (NSCLC). Nude mice bearing xenografts of H-460 and A-549 NSCLC were treated daily with these peptide analogues for 4 weeks. The treatment resulted in growth inhibition of H-460 by 22-77% and A-549 NSCLCs by 64-84%. The inhibition of tumor growth was associated with a down-regulation of members of EGFR/HER family. A significant reduction of the levels of expression of EGFR/HER family on both tumors varied from 29-96%: the greatest inhibition being induced by RC-3940-II. Similarly, a significant decrease in the levels of VEGF-A in tumors by 19-60% and VEGF receptors (VEGF-R1, 24-74% and VEGF-R2, 25-50%) was detected after therapy. An up-regulation of Bax by 21-63% and a down-regulation of Bcl-2 by 23-39% was observed only for H-460 NSCLC. Our study demonstrates that human H-460 and A-549 NSCLC, express receptors for GHRH and bombesin/GRP, and respond to the respective antagonists. The antagonists of bombesin/GRP and GHRH could provide a new strategy for treatment of NSCLC through down-regulation of EGFR/HER family and an interference with the angiogenic and apoptotic pathways.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Bombesin; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Down-Regulation; ErbB Receptors; Growth Hormone-Releasing Hormone; Humans; Lung Neoplasms; Mice; Neovascularization, Pathologic; Peptide Fragments; Proto-Oncogene Proteins c-bcl-2; Receptors, Bombesin; Sermorelin; Vascular Endothelial Growth Factor Receptor-1; Xenograft Model Antitumor Assays

Recent studies show that antagonists of growth hormone-releasing hormone (GH-RH) inhibit proliferation of various cancers indirectly through blockage of the endocrine GH-insulin-like growth factor (IGF) I axis and directly by an action on tumor cells involving the suppression of autocrine/paracrine IGF-I, IGF-II, or GH-RH. The effectiveness of therapy with GH-RH antagonist JV-1-38 and its mechanisms of action were investigated in NCI-H838 non-small cell lung carcinoma (NSCLC) xenografted s.c. into nude mice and in vitro. Treatment with GH-RH antagonist JV-1-38 significantly (P < 0.05-0.001) inhibited tumor growth as demonstrated by a 58% decrease in final tumor volume, 54% reduction in tumor weight, and the extension of tumor-doubling time from 8.5 +/- 1.38 to 12 +/- 1.07 days as compared with controls. Using ligand competition assays with (125)I-labeled GH-RH antagonist JV-1-42, specific high-affinity binding sites for GH-RH were found on tumor membranes. Reverse transcription-PCR revealed the expression of mRNA for GH-RH and splice variant 1 (SV(1)) of GH-RH receptor in H838 tumors. Reverse transcription-PCR analysis also demonstrated that H838 tumors express IGF-I and IGF-I receptors. Tumoral concentration of IGF-I and its mRNA expression were significantly decreased by 25% (P = 0.05) and 65% (P < 0.001), respectively, in animals receiving JV-1-38, whereas serum IGF-I levels remained unchanged. In vitro studies showed that H838 cells secreted GH-RH and IGF-I into the medium. The growth of tumor cells in vitro was stimulated by IGF-I and inhibited by GH-RH antagonist JV-1-38 and a GH-RH antiserum. Our results extend the findings on the involvement of IGF-I in NSCLC and suggest that GH-RH may be an autocrine growth factor for H838 NSCLC. The antitumorigenic action of GH-RH antagonists could be partly direct and mediated by SV(1) of tumoral GH-RH receptors. The finding of GH-RH and SV(1) of GH-RH receptors in NSCLC provides a new approach to the treatment of this malignancy based on the use of antagonistic analogues of GH-RH.

Topics: Adenocarcinoma; Animals; Cell Division; Cell Line, Tumor; Dose-Response Relationship, Drug; Growth Hormone-Releasing Hormone; Humans; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Lung Neoplasms; Male; Mice; Middle Aged; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sermorelin; Xenograft Model Antitumor Assays