Background-An endogenous inhibitor of nitric oxide synthase, asymmetric dimethylarginine (ADMA), is elevated in patients with type 2 diabetes mellitus (DM). This study explored the mechanisms by which ADMA becomes elevated in DM. Methods and Results-Male Sprague-Dawley rats were fed normal chow or high-fat diet (nϭ5 in each) with moderate streptozotocin injection to induce type 2 DM. Plasma ADMA was elevated in diabetic rats (1.33Ϯ0.31 versus 0.48Ϯ0.08 mol/L; PϽ0.05). The activity, but not the expression, of dimethylarginine dimethylaminohydrolase (DDAH) was reduced in diabetic rats and negatively correlated with their plasma ADMA levels (PϽ0.05). DDAH activity was significantly reduced in vascular smooth muscle cells and human endothelial cells (HMEC-1) exposed to high glucose (25.5 mmol/L). The impairment of DDAH activity in vascular cells was associated with an accumulation of ADMA and a reduction in generation of cGMP. In human endothelial cells, coincubation with the antioxidant polyethylene glycol-conjugated superoxide dismutase (22 U/mL) reversed the effects of the high-glucose condition on DDAH activity, ADMA accumulation, and cGMP synthesis.

Background-Hyperlipidemia is associated with endothelial dysfunction, an early event in atherosclerosis and predictor of risk for future coronary artery disease. Epidemiological studies suggest that increased dietary intake of antioxidants reduces the risk of coronary artery disease. The purpose of this study was to determine whether antioxidant vitamin therapy improves endothelial function and affects surrogate biomarkers for oxidative stress and inflammation in hyperlipidemic children. Methods and Results-In a randomized, double-blind, placebo-controlled trial, the effects of antioxidant vitamins C (500 mg/d) and E (400 IU/d) for 6 weeks and the National Cholesterol Education ProgramStep II (NCEP-II) diet for 6 months on endothelium-dependent flow-mediated dilation (FMD) of the brachial artery were examined in 15 children with familial hypercholesterolemia (FH) or the phenotype of familial combined hyperlipidemia (FCH). Antioxidant vitamin therapy improved FMD of the brachial artery compared with baseline (PϽ0.001) without an effect on biomarkers for oxidative stress (autoantibodies to epitopes of oxidized LDL, F 2 -isoprostanes, 8-hydroxy-2Ј-deoxyguanosine), inflammation (C-reactive protein), or levels of asymmetric dimethylarginine, an endogenous inhibitor of nitric oxide. Conclusions-Antioxidant therapy with vitamins C and E restores endothelial function in hyperlipidemic children. Early detection and treatment of endothelial dysfunction in high-risk children may retard the progression of atherosclerosis.

DNA vaccination is an attractive approach for tumor immunotherapy because of its stability and simplicity of delivery. Advances demonstrate that helper T cell responses play a critical role in initiating immune responses. The aim of the current study is to test whether targeting HPV-16 E7 to the endosomal/lysosomal compartment can enhance the potency of DNA vaccines. We linked the lysosome-associated membrane protein 1 (LAMP-1) to HPV-E7 to construct a chimeric DNA, Sig/E7/LAMP-1 DNA. For in vivo tumor prevention experiments, mice were vaccinated with E7 DNA or Sig/E7/LAMP-1 DNA via gene gun, followed by tumor challenge. For in vivo tumor regression experiments, mice were first challenged with tumor cells and then vaccinated with E7-DNA or Sig/E7/LAMP-1 DNA. Intracellular cytokine staining with flow cytometry analysis, cytotoxic T lymphocyte (CTL) assays, enzyme-linked immunoabsorbent assay (ELISA), and enzyme-linked immunospot (ELISPOT) assays were used for in vitro E7-specific immunological studies. In both tumor prevention and tumor regression assays, Sig/E7/LAMP-1 DNA generated greater antitumor immunity than did wild-type E7 DNA. In addition, mice vaccinated with Sig/E7/LAMP-1 DNA had greater numbers of E7-specific CD4+ helper T cells, higher E7-specific CTL activity, and greater numbers of CD8+ T cell precursors than did mice vaccinated with Sig/E7 or wild-type E7 DNA. Sig/E7 generated a stronger E7-specific antibody response than did Sig/E7/LAMP-1 or wild-type E7 DNA. Our results indicate that linkage of the antigen gene to an endosomal/lysosomal targeting signal may greatly enhance the potency of DNA vaccines.

It is a sad fact that despite being almost completely preventable through human papillomavirus (HPV) vaccination and screening, cervical cancer remains the fourth most common cancer to affect women worldwide. Persistent high-risk HPV (hrHPV) infection is the primary etiologic factor for cervical cancer. Upward of 70% of cases are driven by HPV types 16 and 18, with a dozen other hrHPVs associated with the remainder of cases. Current standard-of-care treatments include radiotherapy, chemotherapy, and/or surgical resection. However, they have significant side effects and limited efficacy against advanced disease. There are a few treatment options for recurrent or metastatic cases. Immunotherapy offers new hope, as demonstrated by the recent approval of programmed cell death protein 1–blocking antibody for recurrent or metastatic disease. This might be augmented by combination with antigen-specific immunotherapy approaches, such as vaccines or adoptive cell transfer, to enhance the host cellular immune response targeting HPV-positive cancer cells. As cervical cancer progresses, it can foster an immunosuppressive microenvironment and counteract host anticancer immunity. Thus, approaches to reverse suppressive immune environments and bolster effector T-cell functioning are likely to enhance the success of such cervical cancer immunotherapy. The success of nonspecific immunostimulants like imiquimod against genital warts also suggest the possibility of utilizing these immunotherapeutic strategies in cervical cancer prevention to treat precursor lesions (cervical intraepithelial neoplasia) and persistent hrHPV infections against which the licensed prophylactic HPV vaccines have no efficacy. Here, we review the progress and challenges in the development of immunotherapeutic approaches for the prevention and treatment of cervical cancer.