Calcium channels, external calcium concentration and cell proliferation

Evidence for a role for calcium channel proteins in cell proliferation is numerous suggesting that calcium influx is essential in this physiological process. Several studies in the past thirty years have demonstrated that calcium channel expression levels are determinant in cell proliferation. Voltage-gated, store-operated, second messengers and receptor-operated calcium channels have been associated to cell proliferation. However, the relationship between calcium influx and cell proliferation can be uncoupled in transformed and cancer cells, resulting in an external calcium-independent proliferation. Thus, protein expression could be more important than channel function to trigger cell proliferation suggesting that additional channel functions may be responsible to reconcile calcium channel expression and cell proliferation. When needed, external calcium concentration is obviously important for calcium channel function but it also regulates calcium sensing receptor (CaSR) activity. CaSR can up- or down-regulate cell proliferation depending on physiological conditions. CaSR sensitivity to external calcium is within the 0.5 to 5 mM range and therefore, the role of these receptors in cell proliferation must be taken into account. We therefore suggest here that cell proliferation rates could depend on the relative balance between calcium influx and CaSR activation.

ATP released via pannexin-1 hemichannels mediates bladder overactivity triggered by urothelial P2Y6 receptors

In contrast to the well-known signaling role of urothelial ATP to control bladder function, the hypothesis that uracil nucleotides (UTP and/or UDP) also exert autocrine/paracrine actions only recently gained experimental support. Urothelial cells express UDP-sensitive P2Y6 receptors, yet their role in the control of bladder activity has been mostly neglected. This study was designed to investigate the ability of PSB0474, a stable UDP analogue which exhibits selectivity for P2Y6 receptors, to modulate urodynamic responses in the anaesthetized rat in vivo. Instillation of PSB0474 into the bladder increased the voiding frequency (VF) without affecting the amplitude (A) and the duration (Δt) of bladder contractions. PSB0474-induced bladder overactivity was prevented by the selective P2Y6 antagonist, MRS2578. The increase in the VF produced by PSB0474 was also blocked by inhibitors of pannexin-1 hemichannels, (10)Panx or carbenoxolone, when these drugs were applied inside the bladder lumen but not when they were administered intravenously. Reduction of hemichannels pore permeability with H1152 also prevented PSB0474-induced bladder overactivity, but the exocytosis inhibitor, Exo-1, was inactive. PSB0474 increased by 3-fold the urinary ATP content. Implication of hemichannels permeability on PSB0474-induced ATP release was demonstrated by real-time fluorescence video-microscopy measuring the uptake of propidium iodide by intact urothelial cells in the absence and in the presence of MRS2578 or carbenoxolone. Confocal microscopy studies confirmed the co-localization of pannexin-1 and P2Y6 receptors in the rat urothelium. Data indicate that activation of P2Y6 receptors causes bladder overactivity in the anaesthetized rat indirectly by releasing ATP from the urothelium via pannexin-1 hemichannels.

Role of NADPH oxidase-mediated reactive oxygen species in podocyte injury

Proteinuria is an independent risk factor for end-stage renal disease (ESRD) (Shankland, 2006). Recent studies highlighted the mechanisms of podocyte injury and implications for potential treatment strategies in proteinuric kidney diseases (Zhang et al., 2012). Reactive oxygen species (ROS) are cellular signals which are closely associated with the development and progression of glomerular sclerosis. NADPH oxidase is a district enzymatic source of cellular ROS production and prominently expressed in podocytes (Zhang et al., 2010). In the last decade, it has become evident that NADPH oxidase-derived ROS overproduction is a key trigger of podocyte injury, such as renin-angiotensin-aldosterone system activation (Whaley-Connell et al., 2006), epithelial-to-mesenchymal transition (Zhang et al., 2011), and inflammatory priming (Abais et al., 2013). This review focuses on the mechanism of NADPH oxidase-mediated ROS in podocyte injury under different pathophysiological conditions. In addition, we also reviewed the therapeutic perspectives of NADPH oxidase in kidney diseases related to podocyte injury.

The signaling pathway of NADPH oxidase and its role in glomerular diseases

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox), a major source of reactive oxygen species, is a critical mediator of redox signaling. It is well-documented that oxidative stress is associated with the development of glomerular diseases (GN). Hence, the Nox was also thought to be involved in the pathogenesis of GN. However, the expression of Nox in various GN was not consistent, the mechanisms by which the activity of the Nox enzymes in regulating renal cells remains unclear. Signaling pathways might be very important in the pathogenesis of GN. We performed this review to provide a relatively complete signaling pathways flowchart for Nox to the investigators who were interested in the role of Nox in the pathogenesis of GN. Here, we reviewed the signal transduction pathway of Nox and its role in the pathogenesis of GN.

Pannexin 1 involvement in bladder dysfunction in a multiple sclerosis model

Bladder dysfunction is common in Multiple Sclerosis (MS) but little is known of its pathophysiology. We show that mice with experimental autoimmune encephalomyelitis (EAE), a MS model, have micturition dysfunction and altered expression of genes associated with bladder mechanosensory, transduction and signaling systems including pannexin 1 (Panx1) and Gja1 (encoding connexin43, referred to here as Cx43). EAE mice with Panx1 depletion (Panx1^−/−) displayed similar neurological deficits but lesser micturition dysfunction compared to Panx1^+/+ EAE. Cx43 and IL-1β upregulation in Panx1^+/+ EAE bladder mucosa was not observed in Panx1^−/− EAE. In urothelial cells, IL-1β stimulation increased Cx43 expression, dye-coupling, and p38 MAPK phosphorylation but not ERK1/2 phosphorylation. SB203580 (p38 MAPK inhibitor) prevented IL-1β-induced Cx43 upregulation. IL-1β also increased IL-1β, IL-1R-1, PANX1 and CASP1 expression. Mefloquine (Panx1 blocker) reduced these IL-1β responses. We propose that Panx1 signaling provides a positive feedback loop for inflammatory responses involved in bladder dysfunction in MS.

Inhibition of c-Met promoted apoptosis, autophagy and loss of the mitochondrial transmembrane potential in oridonin-induced A549 lung cancer cells

OBJECTIVE

Herein, inhibition of hepatocyte growth factor receptor, c-Met, significantly increased cytochrome c release and Bax/Bcl-2 ratio, indicating that c-Met played an anti-apoptotic role. The following experiments are to elucidate this anti-apoptotic mechanism, then the effect of c-Met on autophagy has also been discussed.

METHODS

Investigated was the influence of c-Met on apoptosis, autophagy and loss of mitochondrial transmembrane potential (Δψm), and the relevant proteins were examined.

KEY FINDINGS

First, we found that activation of extracellular signal-regulated kinase (ERK), p53 was promoted by c-Met interference. Subsequent studies indicated that ERK was the upstream effector of p53, and this ERK-p53 pathway mediated release of cytochrome c and up-regulation of Bax/Bcl-2 ratio. Secondly, the inhibition of c-Met augmented oridonin-induced loss of mitochondrial transmembrane potential (Δψm), resulting apoptosis. Finally, the inhibition of c-Met increased oridonin-induced A549 cell autophagy accompanied by Beclin-1 activation and conversion from microtubule-associated protein light chain 3 (LC3)-I to LC3-II. Activation of ERK-p53 was also detected in autophagy process and could be augmented by inhibition of c-Met. Moreover, suppression of autophagy by 3-methyladenine (3-MA) or small interfering RNA against Beclin-1 or Atg5 decreased oridonin-induced apoptosis. Inhibition of apoptosis by pan-caspase inhibitor (z-VAD-fmk) decreased oridonin-induced autophagy as well and Loss of Δψm also occurred during autophagic process.

CONCLUSION

Thus, inhibiting c-Met enhanced oridonin-induced apoptosis, autophagy and loss of Δψm in A549 cells.

Endothelial control of vasodilation: integration of myoendothelial microdomain signalling and modulation by epoxyeicosatrienoic acids

Endothelium-derived epoxyeicosatrienoic acids (EETs) are fatty acid epoxides that play an important role in the control of vascular tone in selected coronary, renal, carotid, cerebral and skeletal muscle arteries. Vasodilation due to endothelium-dependent smooth muscle hyperpolarization (EDH) has been suggested to involve EETs as a transferable endothelium-derived hyperpolarizing factor. However, this activity may also be due to EETs interacting with the components of other primary EDH-mediated vasodilator mechanisms. Indeed, the transfer of hyperpolarization initiated in the endothelium to the adjacent smooth muscle via gap junction connexins occurs separately or synergistically with the release of K(+) ions at discrete myoendothelial microdomain signalling sites. The net effects of such activity are smooth muscle hyperpolarization, closure of voltage-dependent Ca(2+) channels, phospholipase C deactivation and vasodilation. The spatially localized and key components of the microdomain signalling complex are the inositol 1,4,5-trisphosphate receptor-mediated endoplasmic reticulum Ca(2+) store, Ca(2+)-activated K(+) (KCa), transient receptor potential (TRP) and inward-rectifying K(+) channels, gap junctions and the smooth muscle Na(+)/K(+)-ATPase. Of these, TRP channels and connexins are key endothelial effector targets modulated by EETs. In an integrated manner, endogenous EETs enhance extracellular Ca(2+) influx (thereby amplifying and prolonging KCa-mediated endothelial hyperpolarization) and also facilitate the conduction of this hyperpolarization to spatially remote vessel regions. The contribution of EETs and the receptor and channel subtypes involved in EDH-related microdomain signalling, as a candidate for a universal EDH-mediated vasodilator mechanism, vary with vascular bed, species, development and disease and thus represent potentially selective targets for modulating specific artery function.

Eviprostat activates cAMP signaling pathway and suppresses bladder smooth muscle cell proliferation

Eviprostat is a popular phytotherapeutic agent for the treatment of lower urinary tract symptoms (LUTS). At present, the signaling mechanisms underlying its therapeutic effects are still poorly understood. Given that cAMP has been reported to suppress cell hyperplasia and hypertrophy in various pathological situations, we asked whether the effect of Eviprostat could be ascribed to the activation of the cAMP signaling pathway. In the study, exposure of cAMP response element (CRE)-secreted alkaline phosphatase (SEAP) (CRE-SEAP)-reporter cells to Eviprostat elevated SEAP secretion, which was associated with an increased phosphorylation of vasodilator-stimulated phosphoprotein (VASP) and cAMP-response element-binding protein (CREB), as well as enhanced expression of CRE-regulated protein connexin43, indicating an activation of the cAMP signaling pathway. Consistent with these observations, Eviprostat-induced expression of Cx43 was abolished in the presence of adenylyl cyclase inhibitor SQ22536 or PKA inhibitor H89, whereas it was mimicked by adenylyl cyclase activator, forskolin. Further analysis demonstrated that Eviprostat significantly potentiated the effect of phosphodiesterase 3 (PDE3) inhibitor, but not that of PDE4 inhibitor, on CRE activation. Moreover, Eviprostat suppressed PDGF-induced activation of ERK and Akt and inhibited cell proliferation and hillock formation in both mesangial cells and bladder smooth muscle cells. Collectively, activation of the cAMP signaling pathway could be an important mechanism by which Eviprostat exerts its therapeutic effects for LUTS.

A comparison between the seventh and sixth editions of the American Joint Committee on Cancer/International Union Against classification of gastric cancer

OBJECTIVE

To evaluate the prognostic significance of the seventh edition TNM staging classification for gastric cancer.

BACKGROUND

The seventh edition TNM staging system for gastric cancer was adopted by the American Joint Committee on Cancer/International Union Against Cancer on January 1, 2010, and included major revisions.

METHODS

The authors analyzed data retrospectively collected on patients with gastric cancer who underwent surgery at the Affiliated Hospital of Qingdao University Medical College between 2000 and 2008. A total of 964 patients with gastric cancer who underwent R0 surgical resection were included.

RESULTS

The relative risk (RR) for the seventh edition T classification was found to increase steadily and reasonably compared with the sixth edition. However, the RR for the sixth edition N classification was found to increase steadily and reasonably compared with the seventh edition classification. Cox regression multivariate analysis showed that the sixth edition N classification was superior to the seventh edition N classification as an independent prognostic factor. In survival analysis, the seventh edition TNM classification provided a more detailed classification; however, some subgroups of the seventh edition TNM classification did not demonstrate significantly different survival rates. The combination of the seventh edition T classification and the sixth edition N classification, with ideal RR results, showed significantly different survival rates except for IA and IB.

CONCLUSIONS

The combination of the seventh edition T classification and the sixth edition N classification seems to provide the optimal prognosis.

Critical role of TRPC6 channels in the development of human renal cell carcinoma

Renal cell carcinoma (RCC) is the most common tumor arising from the cells in the lining of tubules in the kidney. Some members of the Ca2+-permeable transient receptor potential canonical (TRPC) family of channel proteins have demonstrated a role in the proliferation of some types of cancer cells. In this study, we investigated the role of TRPC6 in the development of human RCC. RT-PCR and Western blotting were used to investigate TRPC6 expression in 1932 and ACHN cells. Immunohistochemical techniques were applied to study TRPC6 expression in 60 cases of RCC primary tissue samples and 10 cases of corresponding normal renal tissues. To inhibit TRPC6 activity or expression, RNA interference was used. The effects of TRPC6 channels on RCC cell viability and cell cycle progression were investigated by MTT and flow cytometry. TRPC6 was expressed in 1932 and ACHN cells. TRPC6 protein was detected in 73.3% of RCC samples, and there was a significant difference compared with the normal renal samples (30%) (p<0.05). Moreover the level of TRPC6 expression was associated with RCC Fuhrman grade (p<0.01). Blockade of TRPC6 channels in ACHN cells suppressed basal cell proliferation and partially inhibited HGF-induced cell proliferation. Furthermore, inhibition of TRPC6 channels expression prolonged the transition through G2/M phase in ACHN cells. In summary, expression of TRPC6 is markedly increased in RCC specimens and associated with RCC histological grade. TRPC6 plays an important role in ACHN cells proliferation.

Silencing the expression of connexin 43 decreases inflammation and joint destruction in experimental arthritis

The objective of the present study was to determine whether the expression of connexin 43 (Cx43) effected on inflammatory conditions in rat fibroblast-like synoviocytes (FLS) and on rat model of rheumatoid arthritis (RA). The expression of Cx43 in rat FLS stimulated with lipopolysaccharide (LPS) was confirmed by real-time reverse transcriptase polymerase chain reaction (RT-PCR). The effects of small-interfering RNA targeting Cx43 (siCx43) on pro-inflammatory cytokines and chemokine were assessed by real-time RT-PCR and enzyme-linked immunosorbent assay (ELISA). The therapeutic and side effects of siCx43 in a rat model of collagen-induced arthritis (CIA) were examined by in vivo electroporation method. LPS markedly enhanced Cx43 gene expression in rat FLS, with transfection of siCx43 suppressing the over-expression of pro-inflammatory cytokines and the chemokine. Treatment of CIA rats with siCx43 significantly ameliorated paw swelling, and significantly reduced histological arthritis scores and radiographic scores. In histological appearance of rat ankle joints, siCx43 treatment significantly decreased the number of tartrate-resistant acid phosphatase (TRAP)-positive (osteoclast-like) cells. These findings indicated that siCx43 had anti-inflammatory effects in rat FLS and efficiently inhibited the development of CIA. Cx43 may play an important role in the pathophysiology of RA, and may be a potential target molecule for novel RA therapies.

Alteration of podocyte protein expression and localization in the early stage of various hemodynamic conditions

Given that podocalyxin (PCX) and nestin play important roles in podocyte morphogenesis and the maintenance of structural integrity, we examined whether the expression and localization of these two podocyte proteins were influenced in the early stage of various hemodynamic conditions. Mice kidney tissues were prepared by in vivo cryotechnique (IVCT). The distribution of glomeruli and podocyte proteins was visualized with DAB staining, confocal laser scanning microscopy and immunoelectron microscopy. The mRNA levels were examined by real-time quantitative PCR. The results showed the following: Under the normal condition, PCX stained intensely along glomerular epithelial cells, whereas nestin was clearly staining in the endothelial cells and appeared only weakly in the podocytes. Under the acute hypertensive and cardiac arrest conditions, PCX and nestin staining was not clear, with a disarranged distribution, but the colocalization of PCX and nestin was apparent under this condition. In addition, under the acute hypertensive and cardiac arrest conditions, the mRNA levels of PCX and nestin were significantly decreased. Collectively, the abnormal redistribution and decreased mRNA expressions of PCX and nestin are important molecular events at the early stage of podocyte injury during hemodynamic disorders. IVCT may have more advantages for morphological analysis when researching renal diseases.

Copper(II) interacting with the non-steroidal antiinflammatory drug flufenamic acid: structure, antioxidant activity and binding to DNA and albumins

Copper(II) complexes with the non-steroidal antiinflammatory drug flufenamic acid (Hfluf) in the presence of N,N-dimethylformamide (DMF) or nitrogen donor heterocyclic ligands (2,2'-bipyridylamine (bipyam), 1,10-phenanthroline (phen), 2,2'-bipyridine (bipy) or pyridine (py)) have been synthesized and characterized. The crystal structures of [Cu2(fluf)4(DMF)2], 1, and [Cu(fluf)(bipyam)Cl], 2, have been determined by X-ray crystallography. Density functional theory (DFT) (CAM-B3LYP/LANL2DZ/6-31G**) was employed to determine the structure of complex 2 and its analogues (complexes [Cu(fluf)(phen)Cl], 3, [Cu(fluf)(bipy)Cl], 4 and [Cu(fluf)2(py)2], 5). Time-dependent DFT calculations of doublet-doublet transitions show that the lowest-energy band in the absorption spectrum of 2-5 has a mixed d-d/LMCT character. UV study of the interaction of the complexes with calf-thymus DNA (CT DNA) has shown that the complexes can bind to CT DNA with [Cu(fluf)(bipy)Cl] exhibiting the highest binding constant to CT DNA. The complexes can bind to CT DNA via intercalation as concluded by studying the cyclic voltammograms of the complexes in the presence of CT DNA solution and by DNA solution viscosity measurements. Competitive studies with ethidium bromide (EB) have shown that the complexes can displace the DNA-bound EB suggesting strong competition with EB. Flufenamic acid and its Cu(II) complexes exhibit good binding affinity to human or bovine serum albumin protein with high binding constant values. All compounds have been tested for their antioxidant and free radical scavenging activity as well as for their in vitro inhibitory activity against soybean lipoxygenase showing significant activity with [Cu(fluf)(phen)Cl] being the most active.

Connexin43 hemichannel-mediated regulation of connexin43

Background

Many signaling molecules and pathways that regulate gap junctions (GJs) protein expression and function are, in fact, also controlled by GJs. We, therefore, speculated an existence of the GJ channel-mediated self-regulation of GJs. Using a cell culture model in which nonjunctional connexin43 (Cx43) hemichannels were activated by cadmium (Cd²⁺), we tested this hypothesis.

Principal Findings

Incubation of Cx43-transfected LLC-PK1 cells with Cd²⁺ led to an increased expression of Cx43. This effect of Cd²⁺ was tightly associated with JNK activation. Inhibition of JNK abolished the elevation of Cx43. Further analysis revealed that the changes of JNK and Cx43 were controlled by GSH. Supplement of a membrane-permeable GSH analogue GSH ethyl ester or GSH precursor N-acetyl-cystein abrogated the effects of Cd²⁺ on JNK activation and Cx43 expression. Indeed, Cd²⁺ induced extracellular release of GSH. Blockade of Cx43 hemichannels with heptanol or Cx43 mimetic peptide Gap26 to prevent the efflux of GSH significantly attenuated the Cx43-elevating effects of Cd²⁺.

Conclusions

Collectively, our results thus indicate that Cd²⁺-induced upregulation of Cx43 is through activation of nonjunctional Cx43 hemichannels. Our findings thus support the existence of a hemichannel-mediated self-regulation of Cx43 and provide novel insights into the molecular mechanisms of Cx43 expression and function.

Discussion of modifying stage IV gastric cancer based on Borrmann classification

This study aims to investigate the prognostic significance of reclassification of stage IV gastric cancers in conjunction with Borrmann type. A total of 1,673 gastric cancer patients who received a gastrectomy between 1980 and 2003 were retrospectively evaluated. Of the patients, 244 (14.58 %), 344 (20.56 %), 589 (35.21 %), and 496 (29.65 %) had stage I, II, III, and IV cancers, respectively. After Cox regression analysis, Borrmann type was identified to be the independent prognostic factor in stage IV gastric cancer. The disease-specific postoperative survival of patients with Borrmann I, II, and III tumors was clearly distinguished by TNM classification system (P<0.05), while it failed to classify Borrmann IV tumors (P=0.147). Interestingly, the disease-specific postoperative survival of stage IV patients with Borrmann IV tumors (group 1) was significantly poor than the cases with stage IV but not Borrmann IV tumors (group 2), as well as the patients with Borrmann IV while not included in stage IV tumors (group 3) (P=0.022 and P=0.000, respectively). Meanwhile, the disease-specific postoperative survival was not observed as significantly different between group 2 and group 3 (P=0.063); furthermore, group 2+3 had a better prognosis than group 1 (introduced stage IVa vs. stage IVb; P=0.006). Reclassification of stage IV through combining the present TNM classification system with Borrmann type may more accurately predict the prognosis of patients.

Factors associated with peritoneal metastasis in non-serosa-invasive gastric cancer: a retrospective study of a prospectively-collected database

Background

Peritoneal dissemination is the most common type of recurrence in advanced gastric cancer. The main mechanism is thought to be via the exfoliation of free cancer cells (FCCs) from tumor in the gastric serosa. The frequency of recurrence thus increases once the tumor cells penetrate the serosa. However, this type of recurrence also occurs in patients without serosal invasion, though the mechanisms responsible for have not been fully established. We therefore investigated the factors associated with peritoneal dissemination in patients with non-serosa-invasive gastric cancer.

Methods

A total of 685 patients with non-serosa-invasive gastric cancer who underwent curative resection with retrieval of more than 15 nodes were selected. The associations between clinicopathological features and peritoneal dissemination were analyzed. Among them, the tumor infiltrating growth pattern (INF) were classified into α, β and γ according to the Japanese Classification of Gastric Carcinoma (JCGC).

Results

The overall incidence of peritoneal metastasis was 20% (137/685). Age, Borrmann type, differentiation, INF, nodal status and free cancer cells (FCCs) were correlated with peritoneal dissemination using univariate analysis. However, only INF, Borrmann type and TNM node stage were identified as independent correlated factors with peritoneal metastasis by multivariate analysis when FCCs were excluded, and these were also prognostic factors. Peritoneal dissemination was more common in patients with INFγ, Borrmann III/IV and N3 stage. Among patients without FCCs, nodal involvement or vessel invasion, only INF remained an independent associated factor according to multivariate analysis.

Conclusions

Tumor infiltrating growth pattern (INF), together with Borrmann type and TNM node stage, are important factors associated with peritoneal metastasis in non-serosa-invasive gastric cancer.

Vitamin D down-regulates TRPC6 expression in podocyte injury and proteinuric glomerular disease

The transient receptor potential cation channel C6 (TRPC6) is a slit diaphragm protein expressed by podocytes. TRPC6 gain-of-function mutations cause autosomal dominant focal segmental glomerulosclerosis. In acquired proteinuric renal disease, glomerular TRPC6 expression is increased. We previously demonstrated that acquired increased TRPC6 expression is ameliorated by antiproteinuric angiotensin receptor blockers and angiotensin-converting enzyme inhibitors. Vitamin D also has an antiproteinuric effect. We hypothesized that vitamin D reduces proteinuria by affecting TRPC6 expression in podocytes. Adriamycin-induced nephropathy increased TRPC6 mRNA and protein expression and induced proteinuria in rats. Treatment with 1,25-dihydroxyvitamin D3 (1,25-D3) normalized TRPC6 expression and reduced proteinuria. In vitro, podocyte injury induced by adriamycin exposure in cultured podocytes increased TRPC6 expression. Treatment of injured podocytes with 1,25-D3 dose dependently reduced adriamycin-induced TRPC6 expression. Chromatin immunoprecipitation analysis demonstrated that the vitamin D receptor directly binds to the TRPC6 promoter. Moreover, 1,25-D3 reduced TRPC6 promoter activity in a luciferase reporter assay. In 1,25-D3-deficient 25-hydroxy-1α-hydroxylase knockout mice, TRPC6 expression was increased, accompanied by podocyte foot process effacement and proteinuria. 1,25-D3 supplementation normalized TRPC6 expression, podocyte morphology, and proteinuria in these mice. These results demonstrate that vitamin D down-regulates the enhanced TRPC6 expression in in vivo and in vitro podocyte injury, possibly through a direct effect on TRPC6 promoter activity. This TRPC6 down-regulation could contribute to the antiproteinuric effect of vitamin D.

Flufenamic acid as an ion channel modulator

Flufenamic acid has been known since the 1960s to have anti-inflammatory properties attributable to the reduction of prostaglandin synthesis. Thirty years later, flufenamic acid appeared to be an ion channel modulator. Thus, while its use in medicine diminished, its use in ionic channel research expanded. Flufenamic acid commonly not only affects non-selective cation channels and chloride channels, but also modulates potassium, calcium and sodium channels with effective concentrations ranging from 10(-6)M in TRPM4 channel inhibition to 10(-3)M in two-pore outwardly rectifying potassium channel activation. Because flufenamic acid effects develop and reverse rapidly, it is a convenient and widely used tool. However, given the broad spectrum of its targets, experimental results have to be interpreted cautiously. Here we provide an overview of ion channels targeted by flufenamic acid to aid in interpreting its effects at the molecular, cellular, and system levels. If it is used with good practices, flufenamic acid remains a useful tool for ion channel research. Understanding the targets of FFA may help reevaluate its physiological impacts and revive interest in its therapeutic potential.

The integration of macroscopic tumor invasion of adjacent organs into TNM staging system for colorectal cancer

Objective

In addition to pathological TNM (pTNM) staging, the macroscopic staging (surgical TNM, sTNM) is another method used to stage and assess tumors, and it also potentially influences patient treatment guidelines. However, for the same patient, surgeons and pathologists might assess tumor depth differently. We aimed to evaluate the prognosis of patients who exhibit unconformity of intraoperative and postoperative results and propose a revised pT category (r-pT category) to predict survival in colorectal cancer.

Methods and Results

In our study, 948 colorectal cancer patients were reviewed. We proposed a novel r-pT category in which surgical macroscopic T4b (sT4b) is incorporated into the pT category, namely, patients in the pT3 category with sT4b cancers are reclassified as being in the r-pT4a category; patients in the pT4a category with sT4b cancers are reclassified as being in the r-pT4b category. Cancer-specific survival according to the r-pT category was analyzed using Kaplan-Meier survival curves. A two-step multivariate analysis was used to determine correlations between the r-pT category and the prognosis. Harrell’s C statistic was utilized to test the predictive capacity. There were significant prognostic differences among the r-pT subcategories. We substituted the r-pT category for the pT category in current TNM staging in a 2-step multivariate analysis. The Harrell’s C statistical analysis results demonstrated that the r-pT category had superior predictive capacity compared to the pT category (Harrell’ C: 0.668 vs. 0.636; P = 0.002).

Conclusions

Patients in the pT3 category with sT4b cancers, and patients in the pT4a category with sT4b cancers, are potentially under-staged, reclassification into higher categories could potentially benefit these patients. The results indicate that the r-pT category we proposed is potentially superior to the pT category in the assessment of prognosis for colorectal cancer.

Ca(2+)-activated ion currents triggered by ryanodine receptor-mediated Ca(2+) release control firing of inhibitory neurons in the prepositus hypoglossi nucleus

Spontaneous miniature outward currents (SMOCs) are known to exist in smooth muscles and peripheral neurons, and evidence for the presence of SMOCs in central neurons has been accumulating. SMOCs in central neurons are induced through Ca(2+)-activated K(+) (K(Ca)) channels, which are activated through Ca(2+)-induced Ca(2+) release from the endoplasmic reticulum via ryanodine receptors (RyRs). Previously, we found that some neurons in the prepositus hypoglossi nucleus (PHN) showed spontaneous outward currents (SOCs). In the present study, we used whole cell recordings in slice preparations of the rat brain stem to investigate the following: 1) the ionic mechanisms of SOCs, 2) the types of neurons exhibiting frequent SOCs, and 3) the effect of Ca(2+)-activated conductance on neuronal firing. Pharmacological analyses revealed that SOCs were induced via the activation of small-conductance-type K(Ca) (SK) channels and RyRs, indicating that SOCs correspond to SMOCs. An analysis of the voltage responses to current pulses of the fluorescence-expressing inhibitory neurons of transgenic rats revealed that inhibitory neurons frequently exhibited SOCs. Abolition of SOCs via blockade of SK channels enhanced the frequency of spontaneous firing of inhibitory PHN neurons. However, abolition of SOCs via blockade of RyRs reduced the firing frequency and hyperpolarized the membrane potential. Similar reductions in firing frequency and hyperpolarization were also observed when Ca(2+)-activated nonselective cation (CAN) channels were blocked. These results suggest that, in inhibitory neurons in the PHN, Ca(2+) release via RyRs activates SK and CAN channels, and these channels regulate spontaneous firing in a complementary manner.

NADPH oxidase-mediated upregulation of connexin43 contributes to podocyte injury

The gap junction protein connexin43 (Cx43) was markedly increased in podocytes in a rat model of nephrosis induced by puromycin. However, the mechanisms and roles of the altered Cx43 in podocytes are still unclear. Given that oxidative stress mediates podocyte injury under a variety of pathological situations, we examined the possible involvement of an oxidative stress-related mechanism in the regulation of Cx43. Incubation of podocytes with puromycin led to a time- and concentration-dependent loss of cell viability, which was preceded by an elevation in Cx43 levels. Concomitantly, puromycin also induced NOX4 expression and promoted superoxide (O(2)(·-)) generation. Inhibition of NADPH oxidase with apocynin and diphenyleneiodonium chloride or addition of the superoxide dismutase mimetic tempol completely abrogated, whereas the O(2)(·-) donors menadione and 2,3-dimethoxy-1,4-naphthoquinone reproduced, the effects of puromycin on Cx43 expression and cell injury. Further analysis demonstrated that treatment of podocytes with several structurally different gap-junction inhibitors significantly attenuated the cytotoxicity of puromycin. Our results thus indicate that NADPH oxidase-mediated upregulation of Cx43 contributes to podocyte injury.

Downregulation of PMCA2 or PMCA3 reorganizes Ca(2+) handling systems in differentiating PC12 cells

Changes in PMCA2 and PMCA3 expression during neuronal development are tightly linked to structural and functional modifications in Ca(2+) handling machinery. Using antisense strategy we obtained stably transfected PC12 lines with reduced level of PMCA2 or PMCA3, which were then subjected to dibutyryl-cAMP differentiation. Reduced level of neuron-specific PMCAs led to acceleration of differentiation and formation of longer neurites than in control PC12 line. Treatment with dibutyryl-cAMP was associated with retraction of growth cones and intensified formation of varicosities. In PMCA2-reduced cells development of apoptosis and DNA laddering were detected. Higher amounts of constitutive isoforms PMCA1 and PMCA4, their putative extended location to gaps left after partial removal of PMCA2 or PMCA3, together with increased SERCA may indicate the induction of compensatory mechanism in modified cells. Functional studies showed altered expression of certain types of VDCCs in PMCA-reduced cells, which correlated with their higher contribution to Ca(2+) influx. The cell response to PMCAs suppression suggests the interplay between transcription level of two opposite calcium-transporting systems i.e. voltage- and store depletion-activated channels facilitating Ca(2+) influx and calcium pumps responsible for Ca(2+) clearance, as well highlights the role of both neuron-specific PMCA isoforms in the control of PC12 cells differentiation.

Inflammation-based prognostic score predicts survival in patients with advanced gastric cancer receiving biweekly docetaxel and s-1 combination chemotherapy

OBJECTIVES

This study was conducted to determine the prognostic value of the Glasgow Prognostic Score (GPS), an inflammation-based prognostic score composed of C-reactive protein and albumin, for patients with advanced cancer.

METHODS

A total of 83 advanced gastric cancer patients receiving biweekly docetaxel/S-1 treatment (DS) were included in the study. To identify the value of GPS as prognostic factor for disease-specific survival (DSS) and progression-free survival (PFS), univariate and multivariate analyses were performed.

RESULTS

Unresectable tumors were observed in 78 patients and recurrent tumors were detected in 5 patients. Of these, 12 patients underwent gastrectomy. There were significant correlations between the GPS and the neutrophil/lymphocyte ratio. Univariate analysis revealed that the GPS, Eastern Cooperative Oncology Group performance status and gastrectomy after DS treatment significantly affected prognosis. Multivariate analysis showed that the GPS, age and gastrectomy independently influenced DSS, and that the GPS and gastrectomy also influenced PFS. Multivariate analysis restricted to patients without gastrectomy showed that the GPS and age independently affected DSS, and that the GPS influenced PFS.

CONCLUSION

In the low GPS group, it may be possible to obtain favorable outcomes by chemotherapy in advanced gastric cancer patients. However, a well-designed prospective trial in a large patient cohort is required to corroborate the prognostic value of the GPS.

Cordycepin as a sensitizer to tumour necrosis factor (TNF)-α-induced apoptosis through eukaryotic translation initiation factor 2α (eIF2α)- and mammalian target of rapamycin complex 1 (mTORC1)-mediated inhibition of nuclear factor (NF)-κB

Cordycepin (3'-deoxyadenosine) is one of the major bioactive substances produced by Cordyceps militaris, a traditional medicinal mushroom. Cordycepin possesses several biological activities, including both pro-apoptotic and anti-apoptotic properties. In the present report, we investigated an effect of cordycepin on the survival of cells exposed to tumour necrosis factor (TNF)-α. We found that subtoxic doses of cordycepin increased susceptibility of cells to TNF-α-induced apoptosis. It was associated with suppression of nuclear factor-κB (NF-κB), a major prosurvival component involved in TNF-α signalling. The adenosine transporter and A₃ adenosine receptor, but not A₁ and A₂ adenosine receptors, mediated both anti-NF-κB and pro-apoptotic effects. We found that cordycepin had the potential to phosphorylate eukaryotic translation initiation factor 2α (eIF2α) and that activation of eIF2α mimicked the suppressive effect of cordycepin on the NF-κB pathway. Furthermore, activation of eIF2α sensitized cells to TNF-α-induced apoptosis. To identify molecular events downstream of eIF2α, the role of mammalian target of rapamycin complex 1 (mTORC1) was examined. Selective activation of ₃eIF2α, as well as treatment with cordycepin, caused phosphorylation of mTORC1. Rapamycin, an inhibitor of mTORC1, significantly reversed the suppressive effects of eIF2α on NF-κB. These results suggest that cordycepin sensitizes cells to TNF-α-induced apoptosis, at least in part, via induction of the eIF2α-mTORC1 pathway and consequent suppression of NF-κB.

Plasma membrane ion fluxes and NFAT-dependent gene transcription contribute to c-met-induced epithelial scattering

Hepatocyte growth factor (HGF) signaling drives epithelial cells to scatter by breaking cell-cell adhesions and causing them to migrate as solitary cells, a process that parallels epithelial-mesenchymal transition. HGF binds and activates the c-met receptor tyrosine kinase, but downstream signaling required for scattering remains poorly defined. We have applied a chemical biology approach to identify components of HGF signaling that are required for scattering in an in vitro model system. This approach yields a number of small molecules that block HGF-induced scattering, including a calcium channel blocker. We show that HGF stimulation results in sudden and transient increases in ion channel influxes at the plasma membrane. Although multiple channels occur in the membranes of our model system, we find that TrpC6 is specifically required for HGF-induced scattering. We further demonstrate that HGF-induced ion influxes through TrpC6 channels coincide with a transient increase in nuclear factor of activated T-cells (NFAT)-dependent gene transcription and that NFAT-dependent gene transcription is required for HGF-induced cell scattering.

β-Catenin signaling contributes to platelet derived growth factor elicited bladder smooth muscle cell contraction through up-regulation of Cx43 expression

PURPOSE

Increased gap junctions contribute to bladder overactivity but the factors and mechanisms involved in gap junction regulation in the bladder are not well established. We examined whether and how platelet derived growth factor regulates connexin43 in bladder smooth muscle cells.

MATERIALS AND METHODS

Cultured rat bladder smooth muscle cells were treated with growth factors with or without agents that interfere with phosphatidylinositol 3-kinase, mitogen activated protein kinase and β-catenin signaling pathways. Connexin43 expression was examined by Western and Northern blot, and immunochemistry. Functional gap junctions were evaluated by scrape-loading dye transfer assay. Bladder smooth muscle cell contraction was measured by collagen gel contraction.

RESULTS

1) Platelet derived growth factor induced phosphatidylinositol 3-kinase and mitogen activated protein kinase dependent accumulation of nuclear β-catenin. This was followed by increased connexin43 expression. 2) Down-regulation of β-catenin by specific siRNA abolished the connexin43 increasing effect of platelet derived growth factor while β-catenin stimulation due to glycogen synthase kinase inhibition mimicked that effect. 3) Basic fibroblast growth factor and epidermal growth factor also induced connexin43 expression. Their effects were potentiated by platelet derived growth factor. 4) Gap junction inhibition attenuated the bladder smooth muscle cell contraction induced by platelet derived growth factor. Consistently fibroblasts from connexin43 knockout (Cx43-/-) mice showed a much weaker contractile response to platelet derived growth factor than cells from connexin43-wild (Cx43+/+) litter mates.

CONCLUSIONS

Platelet derived growth factor induces connexin43 expression and bladder smooth muscle cell contraction by activating β-catenin signaling. As a convergence point for many signal pathways, β-catenin may be targeted to treat bladder overactivity.

AMP-activated protein kinase (AMPK) controls the aging process via an integrated signaling network

Efficient control of energy metabolic homeostasis, enhanced stress resistance, and qualified cellular housekeeping are the hallmarks of improved healthspan and extended lifespan. AMPK signaling is involved in the regulation of all these characteristics via an integrated signaling network. Many studies with lower organisms have revealed that increased AMPK activity can extend the lifespan. Experiments in mammals have demonstrated that AMPK controls autophagy through mTOR and ULK1 signaling which augment the quality of cellular housekeeping. Moreover, AMPK-induced stimulation of FoxO/DAF-16, Nrf2/SKN-1, and SIRT1 signaling pathways improves cellular stress resistance. Furthermore, inhibition of NF-κB signaling by AMPK suppresses inflammatory responses. Emerging studies indicate that the responsiveness of AMPK signaling clearly declines with aging. The loss of sensitivity of AMPK activation to cellular stress impairs metabolic regulation, increases oxidative stress and reduces autophagic clearance. These age-related changes activate innate immunity defence, triggering a low-grade inflammation and metabolic disorders. We will review in detail the signaling pathways of this integrated network through which AMPK controls energy metabolism, autophagic degradation and stress resistance and ultimately the aging process.

Can the tumor deposits be counted as metastatic lymph nodes in the UICC TNM staging system for colorectal cancer?

OBJECTIVE

The 7th edition of AJCC staging manual implicitly states that only T1 and T2 lesions that lack regional lymph node metastasis but have tumor deposit(s) will be classified in addition as N1c, though it is not consistent in that pN1c is also an option for pT3/T4a tumors in the staging table. Nevertheless, in this TNM classification, how to classify tumor deposits (TDs) in colorectal cancer patients with lymph node metastasis (LNM) and TDs simultaneously is still not clear. The aim of this study is to investigate the possibility of counting TDs as metastatic lymph nodes in TNM classification and to identify its prognostic value for colorectal cancer patients.

METHODS AND RESULTS

In this retrospective study, 513 cases of colorectal cancer with LNM were reviewed. We proposed a novel pN (npN) category in which TDs were counted as metastatic lymph nodes in the TNM classification. Cancer-specific survival according to the npN or pN category was analyzed using Kaplan-Meier survival curves. Univariate and multivariate analyses were performed to identify significant prognostic factors. Harrell's C statistic was used to test the predictive capacity of the prognostic models. The results revealed that the TD was a significant prognostic factor in colorectal cancer. Univariate and multivariate analyses uniformly indicated that the npN category was significantly correlated with prognosis. The results of Harrell's C statistical analysis demonstrated that the npN category exhibited a superior predictive capacity compared to the pN category of the 7th edition TNM classification. Moreover, we also found no significant prognostic differences in patients with or without TD in the same npN categories.

CONCLUSIONS

The counting of TDs as metastatic lymph nodes in the TNM classification system is potentially superior to the classification in the 7th edition of the TNM staging system to assess prognosis and survival for colorectal cancer patients.

Is the seventh edition of the UICC/AJCC TNM staging system reasonable for patients with tumor deposits in colorectal cancer?

OBJECTIVE

To assess the rationality of the seventh edition of TNM staging system on tumor deposits (TDs) and propose a novel subclassification.

SUMMARY BACKGROUND DATA

The TDs had been debated for many years. The seventh edition of TNM staging system proposed a "pN1c" concept. However, the value of the modification is still debated.

METHODS

A total of 1541 patients with colorectal cancer were reviewed. Overall survival rates were compared between patients without LNM but TD (+), and those who were TD (-). The TDs were stratified into the "any T + any N" category. Two-step multivariate analysis was performed to identify significant prognostic factors. Univariate analysis was used to determine whether a correlation existed between the number of TDs and prognosis.

RESULTS

There was a significant prognostic difference between patients without LNM or TDs compared with those with positive TDs. Only in T3N2bM0 there was a significant prognostic difference between LNM (+), TD (+) patients and TD (-) patients. The seventh edition of TNM staging system was substituted by the novel TNM staging system in 2-step multivariate analysis. Only in T3N1cM0 there was a significant prognostic difference between patients with only 1 TD and those with more than 1 TD.

CONCLUSION

The seventh edition of TNM staging system on TDs satisfactorily predicts patients' outcome for those without LNM. Patients who categorized as T3N2bM0TD (+) and T4N2bM0TD (-/+) should be reclassified as stage IV. Number of TDs was not an independent prognostic parameter in the TNM staging system.

Prognostic significance of tumor deposits in gastric cancer patients who underwent radical surgery

BACKGROUND

To investigate the prognostic significance of tumor deposits (TDs) in gastric cancers patients who underwent radical surgery.

METHODS

Clinicopathologic and prognostic data from 2998 gastric cancer patients who underwent R0 surgery with D2/D3 lymphadenectomy were retrospectively reviewed. A TD was defined as discrete foci of tumor found in the perigastric fat or in adjacent ligament away from the leading edge of the tumor and showing no evidence of residual lymph node tissue, but within the lymph drainage area of the primary carcinoma.

RESULTS

TDs were detected in 17.8% of patients. TDs were more frequently observed in cancers of larger size, of Borrmann type 4, with lymphovascular invasion, deeper in depth of invasion, and with extended lymph node metastasis. Multivariate analysis confirmed the presence of TDs as 1 of independent factors predicting a poorer outcome. When stratified by pN category, significant differences in survival were observed between patients with and without TDs for those in pN0/pT1-3, pN1/pT3, pN2/pT1-3 and pN3/pT2-3 category, but not for those in pT4a and pT4b category. Moreover, for cancers in each pN category, the prognosis for patients with TDs in pT1-4a category was similar with that of those without TDs in pT4a category, but significantly better than that of those with or without TDs in pT4b category. A revised pT category and a revised pTNM system were proposed, in which all the cancers with TDs in pT1-4a category were incorporated into those without TDs in pT4a category according to the pN category. Further analysis revealed the revised pT category and the revised pTNM system had better homogeneity, discriminatory ability, and monotonicity of gradients than the American Joint Committee on Cancer (AJCC) pT category and the AJCC pTNM system, respectively, representing optimum prognostic stratification.

CONCLUSION

TDs significantly correlated with gastric cancer patients' survival. It might be more suitable for TDs to be treated as a form of serosal invasion. Consequently, en bloc resection of the primary carcinoma is crucially important, and adjuvant chemotherapy should always be considered if TDs have been detected.

The role of the TRPV6 channel in cancer

Abstract  The TRPV6 channel belongs to the superfamily of transient receptor potential (TRP) channels, subfamily vanilloid, member 6. Its expression in health is mainly confined to epithelial tissue of different organs such as digestive tract, kidney, testis, ovaries and skin. Due to its high calcium selectivity over other TRP channels, this channel was shown to participate in close regulation of calcium homeostasis in the body. In cancer a number of pieces of evidence demonstrate its upregulation and correlation with the advanced stages in prostate, colon, breast, thyroid, and ovarian carcinomas. Little is known about its role in initiation or progression for most of cancers, though in prostate cancer its oncogenic potential in vitro has been suggested. The most probable mechanisms involve calcium signalling in the control of processes such as proliferation and apoptosis resistance, though in some cases first evidence was reported as to its likely protective role in some cancers such as colon cancer. Further studies are needed to confirm whether this channel does really have an oncogenic potential or is just the last hope for transformed cells/tissues to stop cancer.

Evaluation of the seventh edition of American Joint Committee on Cancer TNM staging system for gastric cancer: results from a Chinese monoinstitutional study

BACKGROUND

To investigate the validity of the 7th edition of American Joint Committee on Cancer (AJCC) TNM staging system for gastric cancer with special attention paid to pT2/pT3, pN1/pN2, and pN3a/pN3b category.

MATERIALS AND METHODS

Clinicopathologic data of 1998 patients underwent R0 surgery for histologically proven gastric cancers with >15 lymph nodes retrieved were retrospectively reviewed.

RESULTS

Prognoses were significantly different between pT2 and pT3 categories, between pN1 and pN2 categories, or between pN3a and pN3b categories. Each stage in the 6th edition was divided into the 7th edition stage with different survival rates. Moreover, stage IIIA, IIIB, and IIIC in the 7th edition system was divided into the 6th edition stage with different survival rates. Prognoses for patients in 7th edition T4aN1M0/T3N2M0/T2N3aM0, T4bN0-1M0/T4aN2M0/T3N3aM0, and T4aN3aM0/T4bN2M0 were similar to that of patients in T1N3bM0, T2N3bM0, and T3N3bM0, respectively, but significantly better than that of patients in T2N3bM0, T3N3bM0, and T4aN3bM0, respectively. However, no significant difference could be observed among patients in T4bN3aM0, T4aN3bM0, T4bN3bM0, and stage IV. A revised TNM system was proposed, in which T1N3bM0 was incorporated into stage IIIA, T2N3bM0 into stage IIIB, T3N3bM0 into stage IIIC, T4bN3aM0/T4aN3bM0/T4bN3bM0 into stage IV. Further analyses revealed the revised TNM system had better homogeneity, discriminatory ability, and monotonicity of gradients than the 6th and the 7th edition system.

CONCLUSIONS

It is reasonable to subclassify the 6th edition pT2 category and pN1 category into the 7th edition pT2/pT3 category and pN1/pN2 category, respectively. However, for better prognostic stratification, it might be more suitable for pN3a and pN3b categories to be considered individual determinants of the 7th edition TNM staging system.

Prognostic significance of lymph node station 7 for patients with gastric cancers underwent radical surgery

BACKGROUND

To investigate the validity of gastric cancers with nodes metastasis at Level II stations limited to No. 7 being classified as level-based n1 stage disease and the impact of this revision on lymph node staging.

METHODS

Clinicopathologic features and prognosis of 1,606 node positive gastric cancers were retrospectively reviewed. Four patient groups were classified according to the status of node involvement: Group A, 734 patients with node metastasis at Level I stations; Group B, 317 patients with nodes metastasis at Level II stations limited to No. 7; Group C, 501 patients with nodes metastasis at Level II stations besides No. 7; and Group D, 54 patients with nodes metastasis at Level III stations.

RESULTS

Although the extent of node metastasis for patients in Group B was more severe than that for patients in Group A, clinicopathologic features (especially pT stage) were not significantly different. Although overall survival for patients in Group B was significantly worse than that for patients in Group A, no significant differences in prognosis could be observed when stratified by pN or rN category. A revised level-based n category was established by considering cancers in Group B as level-based n1 stage disease. Multivariate analysis confirmed rN category and the revised level-based n category independently predicted patients' survival. A novel N category was established by combining rN category and the revised level-based n category. Further analysis revealed the novel N category had better homogeneity, discriminatory ability, and monotonicity of gradients than the other node categories, indicating the novel N system might be the most valuable node staging system for prognostic assessment.

CONCLUSION

It might be more suitable for cancers in Group B being classified as level-based n1 stage disease. And we recommend the anatomical location of metastatic lymph nodes also being considered in the categorization of lymph node metastasis.

The PCa Tumor Microenvironment

The tumor microenvironment (TME) is a very complex niche that consists of multiple cell types, supportive matrix and soluble factors. Cells in the TME consist of both host cells that are present at tumor site at the onset of tumor growth and cells that are recruited in either response to tumor- or host-derived factors. PCa (PCa) thrives on crosstalk between tumor cells and the TME. Crosstalk results in an orchestrated evolution of both the tumor and microenvironment as the tumor progresses. The TME reacts to PCa-produced soluble factors as well as direct interaction with PCa cells. In return, the TME produces soluble factors, structural support and direct contact interactions that influence the establishment and progression of PCa. In this review, we focus on the host side of the equation to provide a foundation for understanding how different aspects of the TME contribute to PCa progression. We discuss immune effector cells, specialized niches, such as the vascular and bone marrow, and several key protein factors that mediate host effects on PCa. This discussion highlights the concept that the TME offers a potentially very fertile target for PCa therapy.

The effect of cyclosporine A on the phosphorylation of the AMPK pathway in the rat hippocampus

Cyclosporine A (CsA), an immunosuppressant and calcineurin inhibitor, induces hyperlipidemia in humans and animals. AMP-activated protein kinase (AMPK) is involved in metabolic homeostasis and lipid metabolism through modulating downstream molecules acetyl CoA carboxylase (ACC) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoAR). AMPK activity is regulated by the phosphorylation at the Thr-172 residue by its upstream liver kinase B 1 (LKB1), Ca(2+)/calmodulin-dependent protein kinase kinase β (CaMKKβ) or transforming growth-factor-β-activated kinase 1 (TAK1). AMPK can be deactivated through dephosphorylation by protein phosphatase 2Cα (PP2Cα). In this study, we demonstrated that phosphorylation at Thr-172-AMPK increased with a concurrent increase in the phosphorylation of Ser-431-LKB1 and Thr-184/187-TAK1 in the rat hippocampus at 5 h after an intraperitoneal CsA (50 mg/kg) injection. CsA did not affect the phosphorylation of Thr-196-Ca(2+)/calmodulin-dependent protein kinase 4 (CaMK4) and the amount of PP2Cα. An increased phosphorylation of Ser-79-ACC and Ser-872-HMG-CoAR was also observed. In conclusion, our data indicate that CsA activates the AMPK pathway in the rat hippocampus, which suggests that CsA affects the regulatory signaling pathway of lipid metabolism in the rat brain.

Can lymph node ratio take the place of pN categories in the UICC/AJCC TNM classification system for colorectal cancer?

BACKGROUND

Lymph node ratio (LNR) has been reported to represent a powerful independent prognostic value in some malignancies. The significance of LNR in colorectal cancer is still under debate.

METHODS

A total of 505 patients with stage III colorectal cancer were reviewed. Using running log-rank statistics, we calculated the best cutoff values for LNRs and proposed a novel rN category: rN1, 0% < LNR ≤ 35%; rN2, 35% < LNR ≤ 69%; and rN3, LNR > 69%. A Spearman's correlation coefficient test was used to assess the correlation between the number of retrieved nodes and the number of metastatic nodes, as well as the number of retrieved nodes and the LNRs. Univariate and two-step multivariate analyses were performed, respectively, to identify the significant prognostic clinicopathologic factors.

RESULTS

The 5-year overall survival rate decreased significantly with increasing LNRs: rN(1) = 61% survival rate, rN(2) = 30.3% survival rate, and rN(3) = 11.2% survival rate (P < 0.001). Univariate and two-step multivariate analyses identified the rN category as a significant prognostic factor no matter whether the minimum number of LNs retrieved was met. There was a significant prognostic difference among different rN categories for any pN category, but no apparent prognostic difference was seen between different pN categories in any rN category. Moreover, marked heterogeneity could be seen within III(a-c) substages when survival was compared among rN(1-3) categories but not between pN(1-2) categories.

CONCLUSIONS

rN categories have more potential for predicting patient outcomes and are superior to the UICC/AJCC pN categories. We recommend rN categories for prognostic assessment and rN categories should be reported routinely in histopathological reports.

Validation of the seventh edition of the American Joint Committee on Cancer TNM staging system for gastric cancer

BACKGROUND

The seventh edition of the American Joint Committee on Cancer (AJCC) TNM classification for gastric cancer was published in 2010 and included major revisions. The aim of the current study was to evaluate the validity of the seventh edition TNM classification for gastric cancer based on an Asian population.

METHODS

A total of 2916 gastric cancer patients who underwent R0 surgical resection from 1989 through 2008 in a single institute were included, and were analyzed according to the seventh edition of the TNM classification for validation.

RESULTS

When adjusted using the seventh edition of the TNM classification, upstaging was observed in 771 patients (26.4%) and downstaging was observed in 178 patients (6.1%) compared with the sixth edition of the TNM classification. The relative risk (RR) of seventh edition pT classification was found to be increased with regular intensity compared with the sixth edition pT classification. The RR of seventh edition pN classification was found to be increased with irregular intensity compared with the sixth edition pN classification. In survival analysis, there were significant differences noted for each stage of disease, but only a marginal difference was demonstrated between stage IA and stage IB (P = .049). In the hybrid TNM classification, which combines the seventh edition pT classification and the sixth edition pN classification, both pT and pN classifications demonstrated a more ideal distribution of the RR, and 5-year survival rates also showed a significant difference for each stage (P <.01).

CONCLUSIONS

The seventh edition of the TNM classification was considered valid based on the results of the current study. However, the hybrid TNM classification, comprised of a combination of the seventh edition pT classification and sixth edition pN classification, should be considered for the next edition.

Association of heparanase gene (HPSE-1) single nucleotide polymorphisms with gastric cancer

BACKGROUND

Heparanase activity plays a decisive role in biological processes associated with remodeling of the extracellular matrix (e.g., cancer metastasis, angiogenesis, and inflammation). Heparanase gene overexpression has been associated with advanced stage and poor survival in several cancers. We investigated the potential association between single nucleotide polymorphisms (SNPs) of the HPSE-1 gene, tumor susceptibility, clinicopathological parameters, and survival with gastric cancer among the Han population in northern China.

METHODS

In this case-control study, there were 155 patients with gastric cancer and 204 healthy controls. The genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Chi-square test was performed to exam differences of genotypes or alleles frequency between samples. The effect of various variables on outcome was investigated by multivariate analysis using the Cox proportional hazards model.

RESULTS

We identified four polymorphisms in the HPSE-1 gene. Polymorphisms in introns 2 and 3, exon8, and exon13 occurred at a minor allele frequency of >or=10%. There was an increase in frequency of individuals with a genotype that carried the intron3 (A), exon8 (A), exon13 (G) haplotype (AAG) in patients with gastric cancer compared with healthy individuals (P = 0.0001; OR = 7.467; 95% CI: 2.274-24.509). SNP rs11099592 variant genotypes AG/AA were associated with a Borrmann type classification (P = 0.015; OR = 0.182; 95% CI: 0.049-0.668) and invasion depth (P = 0.020; OR = 0.341; 95% CI: 0.134-0.866), whereas SNP rs4328905 AG genotype was correlated to Lauren diffuse grade (P = 0.027; OR = 0.419; 95% CI 0.191-0.917). SNP rs6856901 variant genotypes GC/CC were associated with a better tumor-related survival (P = 0.028; OR = 0.504; 95% CI: 0.273-0.930) compared with GG genotype.

CONCLUSIONS

HPSE-1 polymorphisms may contribute to gastric tumor characteristics. SNP rs6856901 may be helpful in identifying clinical outcome of patients with gastric cancer.