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Human osteocalcin: a strong promoter for nitric oxide synthase gene therapy, with specificity for hormone refractory

Helen O McCarthy1, Jonathan A Coulter, Jenny Worthington

  • 1School of Pharmacy, McClay Research Centre, Queen's University, Lisburn Road, Belfast, Northern Ireland, UK. h.mccarthy@qub.ac.uk

The Journal of Gene Medicine
|May 2, 2007
PubMed
Abstract

Insights

This study introduces a novel gene therapy approach for hormone refractory prostate cancer using the human osteocalcin promoter to control nitric oxide synthase expression. The therapy demonstrated targeted cell specificity and reduced cancer cell survival in androgen-independent prostate cancer cells.

Area of Science:

  • Oncology
  • Gene Therapy
  • Molecular Biology

Background:

  • Gene therapy is a promising strategy for hormone refractory prostate cancer (HRPC).
  • The human osteocalcin (hOC) promoter was investigated for controlling transgene expression.
  • Inducible nitric oxide synthase (iNOS) is a target for cancer therapy.

Purpose of the Study:

  • To evaluate the efficacy of the hOC promoter for inducible nitric oxide synthase (iNOS) gene therapy in HRPC.
  • To assess the target cell specificity and cytotoxicity of hOC/iNOS in prostate cancer models.
  • To compare hOC/iNOS with constitutively driven iNOS expression.

Main Methods:

  • Human prostate cancer cell lines (PC3, DU145, LNCaP) and control cells were transfected with hOC/iNOS or CMV/iNOS plasmids.
  • Transfection was achieved using a cationic lipid vector.
  • Assays included Western blotting, Greiss test for nitrite measurement, and clonogenic assays.

Main Results:

  • hOC/iNOS transfection increased iNOS protein and nitrite levels in androgen-independent PC3 and DU145 cells.
  • No significant cytotoxicity was observed in androgen-dependent LNCaP cells or non-prostate cell lines.
  • Cell survival was significantly reduced (to 10-20%) in PC3 and DU145 cells with both hOC/iNOS and CMV/iNOS.

Conclusions:

  • The hOC promoter enables tumor-type specific transgene activation of iNOS in androgen-independent prostate cancer cells.
  • Nitric oxide generation with hOC/iNOS is comparable to constitutively driven iNOS.
  • This study provides a foundation for developing hOC/iNOS gene therapy for HRPC.

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