Cytochrome P450 (CYP) arachidonic acid epoxygenase 2J2 converts arachidonic acid to four regioisomeric epoxyeicosatrienoic acids, which exert diverse biological activities in cardiovascular system and endothelial cells. However, it is unknown whether this enzyme highly expresses and plays any role in cancer. In this study, we found that very strong and selective CYP2J2 expression was detected in human carcinoma tissues in 101 of 130 patients (77%) as well as eight human carcinoma cell lines but undetectable in adjacent normal tissues and nontumoric human cell lines by Western, reverse transcription-PCR, and immunohistochemical staining. In addition, forced overexpression of CYP2J2, and CYP BM3F87V or addition of epoxyeicosatrienoic acids (EET) in cultured carcinoma cell lines in vitro markedly accelerated proliferation by analyses of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, cell accounts, and cell cycle analysis, and protected carcinoma cells from apoptosis induced by tumor necrosis factor A (TNF-A) in cultures. In contrast, antisense 2J2 transfection or addition of epoxygenase inhibitors 17-ODYA inhibited proliferation and accelerated cell apoptosis induced by TNF-A. Examination of signaling pathways on the effects of CYP2J2 and EETs revealed activation of mitogenactivated protein kinases and PI3 kinase-AKT systems and elevation of epithelial growth factor receptor phosphorylation level. These results strongly suggest that CYP epoxygenase 2J2 plays a previously unknown role in promotion of the neoplastic cellular phenotype and in the pathogenesis of a variety of human cancers. (Cancer Res 2005; 65(11): 4707-15)

Arachidonic acid cytochrome P-450 (CYP) hydroxylase 4A isoforms, including 4A1, 4A2, 4A3 and 4A8 in the rat kidney, catalyze arachidonic acid to produce 19/20-Hydroxyeicosatetraenoic acids (20-HETE), a biologically active metabolite, which plays an important role in the regulation of blood pressure. However, controversial results have been reported regarding the exact role of 20-HETE on blood pressure. In the present study, we used recombinant adenoassociated viral vector (rAAV) to deliver CYP 4A1 cDNA and antisense 4A1 cDNA into Sprague-Dawley (SD) rats and spontaneously hypertensive rats (SHR), respectively, to investigate the effects of long-term modifications of blood pressure and the potential for gene therapy of hypertension. The mean systolic pressure increased by 14.2±2.5 mm Hg in rAAV·4A1-treated SD rats and decreased by 13.7±2.2 mm Hg in rAAV·anti4A1-treated SHR rats 5 weeks after the injection compared with controls and these changes in blood pressure were maintained until the experiments ended at 24 weeks. In 4A1 treated animals CYP4A was overexpressed in various tissues, but preferentially in the kidney at both mRNA and protein levels. In anti-4A1-treated SHR, CYP4A mRNA in various tissues was probed, especially in kidneys, but 4A1 protein expression was almost completely inhibited. These results suggest that arachidonic acid CYP hydroxylases contribute not only to the maintenance of normal blood pressure but also to the development of hypertension. rAAV-mediated anti4A administration strategy has the potential to be used as targeted gene therapy in human hypertension by blocking expression of CYP 4A in kidneys.

Aim: The overexpression of the human tissue kallikrein (HK) gene can reduce blood pressure and ameliorate the secondary syndromes associated with hypertension in animal models. The current study was designed to investigate hy‐potensive effect of intramuscular delivery of HK gene. Methods: We generated an recombinant adeno‐associated virus (rAAV) vector expressing human tissue kallikrein under the control of a cytomegalovirus promoter and administered the rAAV‐HK vector to a spontaneously hypertensive rat model at a dose of 1×1010 virons/rat through intramuscular injection. Results: A persistent, high‐level expression of HK post‐gene delivery was confirmed by ELISA. The systolic blood pressure in the rats receiving rAAV‐LacZ and saline increased from 171.3 mmHg to 182.3 mmHg 28 weeks’post injection. In contrast, the delivery of the HK gene by AAV vectors attenuated the increase of the systolic blood pressure in the treated group. The systolic blood pressure was only slightly lowered (from a level of 174 mmHg to 170.5 mmHg) post‐vector administration. The difference in blood pressure between the treated group and the control groups is statistically significant at 12.6 mmHg. The hypotensive effect of rAAV‐HK persisted until the end of the testing period. In addition, a significant amelioration of cardiovascular hypertrophy, renal injury, and collagen depositions in the rAAV‐HK‐treated animals were also observed. Conclusion: All the effects are comparable with those of intravenous delivery. Therefore, the intramuscular administration of rAAV‐HK may be used in gene therapy for hypertension.