Transforming iodoquinol into broad spectrum anti-tumor leads: Repurposing to modulate redox homeostasis

We managed to repurpose the old drug iodoquinol to a series of novel anticancer 7-iodo-quinoline-5,8-diones. Twelve compounds were identified as inhibitors of moderate to high potency on an inhouse MCF-7 cell line, of which 2 compounds (5 and 6) were capable of reducing NAD level in MCF-7 cells in concentrations equivalent to half of their IC₅₀s, potentially due to NAD(P)H quinone oxidoreductase (NQO1) inhibition. The same 2 compounds (5 and 6) were capable of reducing p53 expression and increasing reactive oxygen species levels, which further supports the NQO-1 inhibitory activity. Furthermore, 4 compounds (compounds 5-7 and 10) were qualified by the Development Therapeutic Program (DTP) division of the National Cancer Institute (NCI) for full panel five-dose in vitro assay to determine their GI₅₀ on the 60 cell lines. All five compounds showed broad spectrum sub-micromolar to single digit micromolar GI₅₀ against a wide range of cell lines. Cell cycle analysis and dual staining assays with annexin V-FITC/propidium iodide on MCF-7 cells confirmed the capability of the most active compound (compound 5) to induce cell cycle arrest at Pre-G1 and G2/M phases as well as apoptosis. Both cell cycle arrest and apoptosis were affirmed at the molecular level by the ability of compound 5 to enhance the expression levels of caspase-3 and Bax together with suppressing that of CDK1 and Bcl-2. Additionally, an anti-angiogenic effect was evident with compound 5 as supported by the decreased expression of VEGF. Interesting binding modes within NQO-1 active site had been identified and confirmed by both molecular docking and dymanic experiments.

Alcohol suppresses cardiovascular diurnal variations in male normotensive rats: Role of reduced PER2 expression and CYP2E1 hyperactivity in the heart

BACKGROUND AND AIMS

The molecular mechanism of the adverse effects of ethanol on diurnal cardiovascular regulation remains unknown. In separate studies, the cardiac circadian rhythm protein period-2 (PER2) confers cardioprotection and, in other organs, PER2 interaction with the ethanol-metabolizing enzyme CYP2E1 underlies, via heme oxygenase-1 (HO-1) upregulation, tissue injury/dysfunction. Here, we hypothesized that suppressed PER2 expression and elevated CYP2E1/HO-1 levels in the heart underlie the disrupted diurnal cardiovascular rhythm/function in alcohol-fed normotensive rats.

METHODS

In ethanol-fed (5%, w/v; 8 weeks) or isocaloric liquid diet-fed male rats, diurnal changes in blood pressure (BP), heart rate (HR), HR vagal variability index, root mean square of successive beat-to-beat differences in beat-interval duration (rMSSD), and cardiac function were measured by radiotelemetry and echocardiography followed by ex vivo molecular studies.

RESULTS

Radiotelemetry findings showed ethanol-evoked reductions in BP (during the dark cycle), rMSSD (during both cycles), and in diurnal differences in BP and rMSSD. Echocardiography findings revealed significant (p < 0.05) reductions in ejection fraction and fractional shortening (weeks 4-6) in the absence of cardiac remodeling (collagen content). Hearts of ethanol-fed rats exhibited higher (p < 0.05) CYP2E1 activity (50%) and HO-1 expression (63%), along with reduction (p < 0.05) in PER2 levels (29%), compared with the hearts of isocaloric diet-fed control rats.

CONCLUSIONS

Our novel findings implicate upregulations of CYP2E1/HO-1 and downregulation of the circadian rhythm cardioprotective protein PER2, in the heart, in the chronic deleterious diurnal cardiovascular effects of alcohol in male rats.

Abstract P144: DHA is a Superior Treatment Over 12/15-lipoxygenase Inhibition in LPS-induced Acute Kidney Injury via Increased Resolvin D2 and IL-10 Levels

Acute kidney injury (AKI) is characterized by loss of kidney function and is often associated with high mortality rate. The polyunsaturated, omega-3 fatty acid, docosahexaenoic acid (DHA), has a promising role in preventing AKI; however; DHA reno-protective mechanism remains unclear. Our aim is to investigate whether and how DHA attenuates lipopolysaccharide (LPS)-induced AKI. Four groups of wild type C57BL/6 (WT) mice were used; control, LPS injected (4 mg/kg i.p), LPS treated with the 12/15-lipoxygenase (12/15-LO) inhibitor baicalein (20 mg/kg i.p for 6 days) and LPS treated with DHA (50 mg/kg i.p for 6 days). LPS-injected mice showed significant elevation in markers of renal injury as urinary excretion levels of protein, podocalyxin and albumin were elevated compared to WT untreated mice (albuminuria was 112±4 vs. 8±1 μg/day and podocalyxin was 3.5±0.6 vs. 0.6±0.1 μg/day in LPS injected mice vs. control WT, P< 0.05). The elevation in renal injury markers were also associated with increases in urinary excretion of thiobarbituric acid reactive substance (TBARs), as a marker of oxidative stress and monocyte chemoattractant protein-1 (MCP-1), as a marker of inflammation, in LPS injected mice. Treatment of LPS injected mice with either DHA or baicalein significantly reduced markers of renal injury, inflammation and oxidative stress. DHA or baicalein treatment also significantly reduced the elevation in renal mRNA expression levels of intercellular adhesion molecule 1 (ICAM-1) and tumor necrosis factor-α (TNF-α) in LPS injected mice. DHA was superior over baicalein in reducing renal expression of Interleukin-6 (IL-6) and IL-1β and in increasing the renal expression of the anti-inflammatory cytokine IL-10 in LPS injected mice. DHA reduced renal tubular necrosis and vaculated cells and lowered renal expression of CD45, a marker of leucocyte adhesion, in LPS injected mice. DHA also restored the decrease in plasma resolvin D2 (RvD2) in LPS injected mice. In conclusion, our data suggest that 12/15-LO activation is involved in LPS-induced acute kidney injury and DHA is a superior treatment over 12/15-LO inhibitor in preventing LPS-induced kidney injury, at least in part, via 12/15-LO-induced resolvin D2.