Archives of Pharmacal Research

The reperfusion of blood flow occurred in a number of conditions such as stroke and organ transplantation immensely augments tissue injury and causes more severe damage than prolonged ischemia. In the present study, we designed a novel double-layer parallel-plate flow chamber (PPFC) to develop an in vitro ischemia/reperfusion (I/R) injury model and examined the effects of I/R on inflammatory responses in human microvascular endothelial cells (HMEC-1). The expression of pro-inflammatory mediators, such as interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), E-selectin, and vascular cell adhesion molecule-1 (VCAM-1) in HMEC-1 was measured by quantitative real-time RT-PCR. The cells were also pre-treated with antioxidant pyrrolidine dithiocarbamate (PDTC) to verify involvement of an oxidative mechanism in I/R injury in vitro. The morphological changes and attenuated expression of pro-inflammatory mediators were observed in HMCE-1 exposed to the physiological flow. In contrast, I/R markedly and significantly up-regulated expression of pro-inflammatory mediators in HMEC-1. Additionally, pretreatment with PDTC significantly reduced I/R-mediated overexpression of pro-inflammatory mediators. The data from the present study provide evidence demonstrating that our newly designed PPFC can be utilized as an effective in vitro cell culture model system to develop new drugs specifically targeting against ischemia/reperfusion (I/R) injury.

This study evaluated the effect of α-tocopherol (α-TC), íschemic preconditioning (IPC) or combination on the extent of mitochondrial injury caused by hepatic ischemia/reperfusion (I/R). Rats were pretreated with α-TC (20 mg/kg per day, i.p.) for 3 days before sustained ischemia. A rat liver was preconditioned with 10 min of ischemia and 10 min of reperfusion, and was then subjected to 90 min of ischemia followed by 5 h or 24 h of reperfusion. I/R increased the ami-notransferase activity and mitochondrial lipid peroxidation, whereas it decreased the mitochondrial glutamate dehydrogenase activity. αand IPC individually attenuated these changes. αcombined with IPC (α-TC+IPC) did not further attenuate the changes. The mitochondrial glutathione content decreased after 5 h reperfusion. This decrease was attenuated by α-TC, IPC, and α-TC+IPC. The significant production of peroxides observed after 10 min reperfusion subsequent to sustained ischemia was attenuated by αIPC, and α-TC+IPC. The mitochondria isolated after I/R were rapidly swollen. However, this swelling rate was reduced by α-TC, IPC, and α-TC+IPC. These results suggest that either αor IPC reduces the level of mitochondrial damage associated with oxidative stress caused by hepatic I/R, but αcombined with IPC offers no significant additional protection.

Rho-associated coiled-coil-containing protein kinase (ROCK)/Lin11, Isl-1 and Mec-3 kinase (LIMK)/cofilin-signaling cascades are stimulated by receptor tyrosine kinases, G protein-coupled receptors, integrins and its ligands, growth factors, hormones, fibronectin, collagen, and laminin. Activated signaling cascades can cause transit from normal cells to cancer cells by modulating actin/filament dynamics. In various cancers including breast, prostate, and colorectal cancers, high expression or activity of each cascade protein is significantly associated with poor survival rate of patients as well as aggressive metastasis. Silencing ROCK, LIMK, or cofilin can abrogate their activities and inhibit cancer cell growth, invasion, and metastasis. Therefore ROCK/LIMK/cofilin signaling proteins might be good candidates to develop cancer prevention strategies or therapeutics. Currently, netarsudil, a ROCK inhibitor, is only used in clinical patients for glaucoma or ocular hypertension, but not for cancer. In this review, we will discuss comprehensive ROCK/LIMK/cofilin signaling pathway in cancers and its inhibitors for developing cancer therapy.

Three known isoquinoline alkaloids were isolated from the chloroform-soluble fraction of the methanolic extract of the aerial parts ofCorydalis incisa (Papaveraceae) through repeated column chromatography. Their chemical structures were elucidated as corynoline (1), corynoloxine (2) and 6-oxocorynoline (3) using spectroscopic analysis. Compounds 1-3 exhibited cytotoxicity against human A549, SK-OV-3, SK-MEL-2 and HCT15 tumor cells.

The behavioral response, dopamine metabolism, and characteristics of dopamine subtypes after developing the hyperglycemia were studied in the striata of rats. In animals developed hyperglycemia, the on-set and duration of cataleptic behavior responded to SCH 23390 injection was delayed and shortened, respectively. However, the cataleptic responses to spiperone occurred significantly earlier in on-set and prolonged in duration. Dopamine metabolites, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), were significantly reduced in the striata of hyperglycemic rats. However, level of DA was significantly increased. It is noted that the ratios of DOPAC and HVA to DA were decreased, suggesting decreased turnover of DA. The affinity of striatal D-1 receptors was significantly increased without changes in the number of binding sites, while the maximum binding number of D-2 receptors was significantly increased without affecting its affinity in the diabetic rats. These results indicate that the dopaminergic activity in the striata was altered in hyperglycemic rats. Furthermore, it suggests that the upregulation of dopamine receptors might be due to the decreased dopamine metabolism.

Quercetin, a representative flavonoid, is a compound of low molecular weight found in various colored plants and vegetables. Quercetin shows a wide range of neuropharmacological activities. In fact, quercetin naturally exists as monomer-(quercetin-3-O-rhamnoside) (Rham1), dimer-(Rutin), or trimer-glycosides [quercetin-3-(2G-rhamnosylrutinoside)] (Rham2) at carbon-3 in fruits and vegetables. The carbohydrate components are removed after ingestion into gastrointestinal systems. The role of the glycosides attached to quercetin in the regulation of γ-aminobutyric acid class C (GABAC) receptor channel activity has not been determined. In the present study, we examined the effects of quercetin glycosides on GABAC receptor channel activity by expressing human GABAC alone in Xenopus oocytes using a two-electrode voltage clamp technique and also compared the effects of quercetin glycosides with quercetin. We found that GABA-induced inward current (I GABA ) was inhibited by quercetin or quercetin glycosides. The inhibitory effects of quercetin and its glycosides on I GABA were concentration-dependent and reversible in the order of Rutin ≈ quercetin ≈ Rham 1 > Rham 2. The inhibitory effects of quercetin and its glycosides on I GABA were noncompetitive and membrane voltage-insensitive. These results indicate that quercetin and its glycosides regulate GABAC receptor channel activity through interaction with a different site from that of GABA, and that the number of carbohydrate attached to quercetin might play an important role in the regulation of GABAC receptor channel activity.