Antioxidant activity of growth hormone-releasing hormone antagonists in LNCaP human prostate cancer line

Nektarios Barabutis, Andrew V Schally

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

Hypothalamic growth hormone-releasing hormone (GHRH) controls the release of growth hormone and acts as a growth factor in various tumors. Potent antagonistic analogues of GHRH have been synthesized that strongly suppress the growth of diverse cancers through several mechanisms. However, the influence of GHRH antagonists on the redox (reduction/oxidation) status of cancers has not been investigated. Cellular generation of reactive oxygen species (ROS) is central to redox signaling and is implicated in the initiation, development, and progression of cancer. In this study, we evaluated by Western blot the effects in vitro of GHRH and its antagonist JMR-132 on proliferating cell nuclear antigen, tumor suppressor protein p53, transcription factor NF-κB p50 and its phosphorylated form, caspase 3, and cleaved caspase 3 in the LNCaP human prostate cancer cell line. GHRH stimulated and GHRH antagonist inhibited the expression of the major antioxidant enzymes, as well as the expression of COX 2 and cytochrome c oxidase IV, which are enzymes involved in the generation of ROS. GHRH augmented and GHRH antagonist suppressed lipid and protein oxidative stress markers, as well as the intracellular generation of ROS. In all these tests, GHRH antagonists exerted strong antioxidant activity. Because the metabolism of ROS and oxidative stress have been associated with initiation and progression of not only prostate tumors but also other malignancies, our findings reinforce previous experimental evidence that GHRH antagonists could be useful for cancer therapy.

Original languageEnglish
Pages (from-to)20470-20475
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume105
Issue number51
DOIs
StatePublished - Dec 23 2008

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Hormone Antagonists
Growth Hormone-Releasing Hormone
Prostatic Neoplasms
Antioxidants
Reactive Oxygen Species
Neoplasms
Caspase 3
Oxidative Stress
Hypothalamic Hormones
Tumor Suppressor Protein p53
Proliferating Cell Nuclear Antigen
Electron Transport Complex IV
Enzymes
Growth Hormone
Prostate
Intercellular Signaling Peptides and Proteins
Transcription Factors
Western Blotting

Keywords

  • Antioxidative activity
  • GHRH
  • Oxidative stress
  • ROS

ASJC Scopus subject areas

  • General

Cite this

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