AcKNoWLedgeMeNTSWe acknowledge the financial support from the NIH grant CA 102264. AbSTRAcTCurcumin, a major active component of turmeric, is known to induce apoptosis in several types of cancer cells, but little is known about its activity in chemoresistant cells. Hence, the aim of the present study was to investigate the anticancer properties of curcumin in cisplatin-resistant human ovarian cancer cells in vitro. The results indicated that curcumin inhibited the proliferation of both cisplatin-resistant (CR) and sensitive (CS) human ovarian cancer cells almost equally. Enhanced superoxide generation was observed in both CR and CS cells treated with curcumin. Curcumin induced G 2 /M phase cell-cycle arrest in CR cells by enhancing the p53 phosphorylation and apoptosis through the activation of caspase-3 followed by PARP degradation. Curcumin also inhibited the phosphorylation of Akt while the phosphorylation of p38 MAPK was enhanced. In summary, our results showed that curcumin inhibits the proliferation of cisplatin-resistant ovarian cancer cells through the induction of superoxide generation, G 2 /M arrest, and apoptosis.

Ovarian cancer is a gynecological malignancy that is commonly treated by cytoreductive surgery followed by cisplatin treatment. However, the cisplatin treatment, although successful initially, is not effective in the treatment of the recurrent disease that invariably surfaces within a few months of the initial treatment. The refractory behavior is attributed to the increased levels of cellular thiols apparently caused by the cisplatin treatment. This observation prompted us to choose a cytotoxic drug whose activity is potentiated by cellular thiols with enhanced specificity toward the thiol-rich cisplatin-resistant cells. We used NCX-4016 [2-(acetyloxy) benzoic acid 3-(nitrooxymethyl)phenyl ester], a derivative of aspirin containing a nitro group that releases nitric oxide in a sustained fashion for several hours in cells and in vivo, and we studied its cytotoxic efficacy against human ovarian cancer cells (HOCCs). Cisplatin-sensitive and cisplatin-resistant (CR) HOCCs were treated with 100 M NCX-4016 for 6 h, and͞or 0.5 g͞ml cisplatin for 1 h and assayed for clonogenecity. NCX-4016 significantly reduced the surviving fractions of cisplatin-sensitive (63 ؎ 6%) and CR (70 ؎ 10%) HOCCs. NCX-4016 also caused a 50% reduction in the levels of cellular glutathione in CR HOCCs. Treatment of cells with NCX-4016 followed by cisplatin showed a significantly greater extent of toxicity when compared with treatment of cells with NCX-4016 or cisplatin alone. In conclusion, this study showed that NCX-4016 is a potential inhibitor of the proliferation of CR HOCCs and thus might specifically kill cisplatin-refractory cancer cells in patients with recurrent ovarian cancer.cisplatin resistance ͉ glutathione ͉ nitric oxide ͉ cytotoxicity ͉ nonsteroidal antiinflammatory drug O varian cancer is the second most commonly diagnosed gynecological malignancy and the fourth leading cause of mortality among women in the United States (1). The high mortality rate is attributed to the lack of early diagnosis of the malignancy and difficulties associated with treatment. The standard treatment includes cytoreductive surgery followed by the administration of chemotherapeutic agents. Platinum-based compounds (e.g., cisplatin and carboplatin) in combination with taxanes (e.g., taxol or paclitaxel), anthracyclines (e.g., doxorubicin), or alkylating agents (e.g., melphalan) are administered to treat the advanced-stage disease (2). However, the overall clinical response with such treatments is only 40-60%. The primary factor that limits the success of chemotherapy in ovarian cancer is the acquired drug resistance in the tumor cell population. Administration of cisplatin results in the development of drug resistance in the cancer cells. Postulated mechanisms of drug resistance include decreased intracellular accumulation of the drug, increased levels of thiols, which inactivate the platinum compound, and the enhancement of DNA repair (3). Even a slight increase in the cisplatin resistance of the tumor may pose a clinically important problem requiring ...

Angiotensin-converting enzyme 2 (ACE2) catalyzes conversion of ANG II to ANG-(1-7). The present study uses newly established proteomic approaches and genetic mouse models to examine the contribution of alternative renal peptidases to ACE2-independent formation of ANG-(1-7). In situ and in vitro mass spectrometric characterization showed that substrate concentration and pH control renal ANG II processing. At pH ≥6, ANG-(1-7) formation was significantly reduced in ACE2 knockout (KO) mice. However, at pH <6, formation of ANG-(1-7) in ACE2 KO mice was similar to that in wild-type (WT) mice, suggesting alternative peptidases for renal ANG II processing. Furthermore, the dual prolyl carboxypeptidase (PCP)-prolyl endopeptidase (PEP) inhibitor Z-prolyl-prolinal reduced ANG-(1-7) formation in ACE2 KO mice, while the ACE2 inhibitor MLN-4760 had no effect. Unlike the ACE2 KO mice, ANG-(1-7) formation from ANG II in PEP KO mice was not different from that in WT mice at any tested pH. However, at pH 5, this reaction was significantly reduced in kidneys and urine of PCP-depleted mice. In conclusion, results suggest that ACE2 metabolizes ANG II in the kidney at neutral and basic pH, while PCP catalyzes the same reaction at acidic pH. This is the first report demonstrating that renal ANG-(1-7) formation from ANG II is independent of ACE2. Elucidation of ACE2-independent ANG-(1-7) production pathways may have clinically important implications in patients with metabolic and renal disease.

Mahmoud Alghamri. M.S., Department of Pharmacology and Toxicology, Wright State University, 2012. Enhanced Angiotensin II-Induced Cardiac and Aortic Remodeling in ACE2 Knockout Mice.Activation of the renin angiotensin system (RAS) is a well-known driving force, governing the aggravation and progression of CVD and associated target organ damage.Angiotensin (Ang) converting enzyme 2 (ACE2), a new member within the RAS family, was first cloned from the ventricle of patient with heart failure. ACE2 was shown to be upregulated under pathological conditions. We hypothesize that loss of ACE2 negatively affects cardiac function and exacerbates hypertrophic cardiomyopathy and aortic remodeling in response to Ang II. Eight weeks old ACE2 knock out (KO) and wild type (WT) mice were infused with Ang II s.c. (1000 ng/kg/min for 4 weeks) using osmotic pumps. Blood pressure (radiotelemetry), cardiac function (echocardiography) and cardiac/aortic structural damage (histology) were examined. At baseline before Ang II, ACE2 KO displayed a normal phenotype for cardiac function and blood pressure. After 4 weeks of Ang II infusion, the mean arterial pressure (MAP) was increased (~40% in WT and ~33% in ACE2 KO) with no differences between groups. However, ACE2 KO responded differently to the increased MAP. Cardiac function analysis revealed severe myocardial dysfunction shown by the lowered EF% (31% vs. 13%) as well as FS% (30% vs 6%) in ACE2 KO vs WT, respectively. In addition, the cardiac dysfunction was associated with hypertrophic cardiomyopathy shown by the increased left ventricular wall thickness as well as heart weight/ body weight ratio. Moreover, collagen staining in the myocardium and aorta revealed higher collagen percentage in ACE2 KO which indicates iv cardiovascular remodeling. Furthermore, results showed enhanced oxidative stress in the myocardium and aorta of Ang II infused ACE2 KO compared to Ang II WT. In conclusion, ACE2 attenuates myocardial maladaptive hypertrophy and cardiovascular remodeling in response to long term Ang II stimulation.v

For prevention and accurate intervention planning, it is crucial to predict if lesions will progress towards cancer. In this study, we investigated the change in optical properties and vascular parameters to characterize skin tissue from mild photodamage to actinic keratosis (AK). Multi-wavelength spatial frequency domain imaging (SFDI) measurements were performed on three patients with clinically normal skin, as well as pre-cancerous actinic keratosis lesions. Our results indicate that there exist significant differences in both optical and vascular parameters between these patients, and that these parameters can be early biomarkers of neoplasia. Ultimately, clinicians can use this noninvasive approach for frequent monitoring of high-risk population.