Midkine (MK), a heparin binding growth factor, and cyclooxygenase-2 (COX-2), a key enzyme in the conversion of arachidonic acid to prostaglandin, are both up-regulated at the mRNA or protein level in many human malignant tumors. Here, we investigated the tumor specificity of both MK and COX-2 promoters in human pancreatic cancer, with the aim to improve the selectivity of therapeutic gene expression. We constructed recombinant adenoviral (Ad) vectors containing either the luciferase (Luc) reporter gene under the control of the COX-2 or MK promoter or the herpes simplex virus thymidine kinase (HSV Tk) gene under the control of the COX-2 promoter and compared the expression with the cytomegalovirus (CMV) promoter. AdMKLuc achieved moderate to relatively high activity upon infection to both primary and established pancreatic carcinoma cells. Of the two COX-2 promoter regions (COX-2M and COX-2L), both revealed a high activity in primary pancreatic carcinoma cells, whereas in the established pancreatic carcinoma cell lines, COX-2L has an approximately equal high activity compared to CMV. In addition, both AdCOX-2M Tk and AdCOX-2L Tk induced marked cell death in response to ganciclovir (GCV) in three of four established pancreatic carcinoma cell lines. From these results, and because it has been reported that AdMKTk and AdCOX-2L Tk in combination with GCV did not reveal significant liver toxicity, we conclude that the MK as well as the COX-2 promoters are promising tumor-specific promoters for Ad vector-based gene therapy of pancreatic cancer.
Bibliographical noteFunding Information:
This work was supported by the National Institute of Health Grants RO1 CA 74242, RO1 HL 50255, National Cancer Institute Grant NO1 CO - 97110, United States Department of Defense Grants PC 970193 and PC 991018, the CapCure Foundation and Training Grant IT32 CA75930 to David T. Curiel, MD, and US Army Breast Grante DOD BC990177 to Igor Dmitriev, PhD. In addition, this work was supported from grants by the European Gastro - Surgical School ( EPGS ) at the Academic Medical Center of the University of Amsterdam and by the Netherlands Organization for Scientific Research (NWO). The authors thank H. Inoue and T. Tanabe of the National Cardiovascular Center Research Institute, Suita, Japan, for providing the plasmid phPES2 containing COX-2 promoter and Shuichiro Matsubara of the Kagoshima University, Kagoshima, Japan, as well as Takashi Muramatsu of the Nagoya University School of Medicine, Nagoya, Japan, for providing the MK promoter.
- Adenovirus vector
- Pancreatic cancer
- Tumor-specific expression