EMX2 is epigenetically silenced and suppresses growth in human lung cancer

Lung cancer is a common cancer and the leading cause of cancer-related death worldwide. Aberrant activation of WNT signaling is implicated in lung carcinogenesis. EMX2, a human homologue of the Drosophila empty spiracles gene is a homeodomain-containing transcription factor. The function of EMX2 has been linked to the WNT signaling pathway during embryonic patterning in mice. However, little is known about the role of EMX2 in human tumorigenesis. In this study, we found that EMX2 was dramatically downregulated in lung cancer tissue samples and this downregulation was associated with methylation of the EMX2 promoter. Restoration of EMX2 expression in lung cancer cells lacking endogenous EMX2 expression suppressed cell proliferation and invasive phenotypes, inhibited canonical WNT signaling, and sensitized lung cancer cells to the treatment of the chemo cytotoxic drug cisplatin. On the other hand, knockdown of EMX2 expression in lung cancer cells expressing endogenous EMX2 promoted cell proliferation, invasive phenotypes and canonical WNT signaling. Taken together, our study suggests that EMX2 may have important roles as a novel suppressor in human lung cancer.

Frameshift and novel mutations in FUS in familial amyotrophic lateral sclerosis and ALS/dementia

OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is a progressive paralytic disorder caused by degeneration of motor neurons. Mutations in the FUS gene were identified in patients with familial ALS (FALS) and patients with sporadic ALS (SALS) from a variety of genetic backgrounds. This work further explores the spectrum of FUS mutations in patients with FALS and patients with FALS with features of frontotemporal dementia (FALS/FTD) or parkinsonism and dementia (FALS/PD/DE).

METHODS

All exons of the FUS gene were sequenced in 476 FALS index cases negative for mutations in SOD1 and TARDBP. A total of 561-726 controls were analyzed for genetic variants observed. Clinical data from patients with FUS mutations were compared to those of patients with known SOD1 and TARDBP mutations.

RESULTS

We identified 17 FUS mutations in 22 FALS families, 2 FALS/FTD families, and 1 FALS/PD/DE family from diverse genetic backgrounds; 11 mutations were novel. There were 4 frameshift, 1 nonsense, and 1 possible alternate splicing mutation. Patients with FUS mutations appeared to have earlier symptom onset, a higher rate of bulbar onset, and shorter duration of symptoms than those with SOD1 mutations.

CONCLUSIONS

FUS gene mutations are not an uncommon cause in patients with FALS from diverse genetic backgrounds, and have a prevalence of 5.6% in non-SOD1 and non-TARDBP FALS, and approximately 4.79% in all FALS. The pathogenicity of some of these novel mutations awaits further studies. Patients with FUS mutations manifest earlier symptom onset, a higher rate of bulbar onset, and shorter duration of symptoms.

ERK/MAPK activation involves hypoxia-induced MGr1-Ag/37LRP expression and contributes to apoptosis resistance in gastric cancer

We previously demonstrated that hypoxia increased the hypoxia-inducible factor (HIF-1)-dependent MGr1-Ag/37LRP expression, which enhanced adhesion of gastric cancer cells to laminin, inhibited drug-induced apoptosis and caused cell adhesion-mediated drug resistance (CAM-DR). Here, we investigated the role of extracellular-regulated kinase (ERK) 1/2 in the signaling mechanisms underlying these events. We found that hypoxia activated ERK activity in vitro and in vivo. Overexpression of mitogen-activated protein kinase (MAPK) kinase (MEK), which preferentially activated ERK, mimics, in a nonadditive way, hypoxia-induced activity of MGr1-Ag/37LRP promoter and expression of MGr1-Ag/37LRP. Furthermore, U0126, the MEK inhibitor, inhibited hypoxia- and MEK-induced MGr1-Ag/37LRP promoter activity in a dose-dependent manner. MEK inhibition also reversed hypoxia- and MEK-induced HIF-1 protein and its activity in a dose-dependent manner. We also investigated reactive oxygen species signaling this response. Exogenous addition of H(2)O(2) was sufficient to activate ERK in a dose-dependent profile. Reactive oxygen species scavengers of H(2)O(2) significantly inhibited hypoxia-induced ERK or HIF-1 activation and sequential expression of MGr1-Ag/37LRP. We also investigated the signaling in hypoxia-induced cell adhesion and apoptosis induced by vincristine. Hypoxia significantly enhanced adhesion of SGC7901 cells to laminin in a time-dependent manner, which might be inhibited by the MEK inhibitor U0126 and MGr1-Ag/37LRP siRNA. Consistent with results of adhesion assay, hypoxia-resistant apoptosis might be reversed by U0126 in a dose-dependent manner. Our results suggest that hypoxia-elicited MGr1-Ag/37LRP expression activated by HIF-1 depends on ERK activation. These events are dependent of reactive oxygen intermediates.

Meta-analysis: polymorphisms in TNF-alpha gene promoter and Crohn's disease

BACKGROUND

Tumour necrosis factor alpha (TNF-alpha) is involved in the pathogenesis of Crohn's disease (CD). However, results on the association between the polymorphisms in TNF-alpha promoter and the risk of CD are inconsistent.

AIM

To perform a quantitative synthesis for the genetic polymorphisms in TNF-alpha promoter and CD risk.

METHODS

Databases were searched (up to 2009) and 31 studies were included. Risks of CD associated with the polymorphisms in TNF-alpha promoter were assessed.

RESULTS

Overall, individuals with -1031 TC+CC genotype had a slightly increased risk to develop CD compared with individuals with -1031 TT genotype (OR, 1.32; 95% CI, 1.03-1.70). In the further stratified analysis, we found Asians with the -1031T>C, -863 C>A and -857 C>T variant polymorphisms have almost one and a half CD risk compared with other genotypes (OR, 1.58; 95% CI, 1.16-2.15; OR, 1.55; 95% CI, 1.18-2.02; OR, 1.54; 95% CI, 1.19-1.99 respectively). We did not find -308 G>A variant associated with CD location and disease behaviours in stratified analysis.

CONCLUSIONS

TNF-alpha polymorphisms in the promoter region might be used as a biomarker for CD risk prediction. Larger studies with mixed ethnicity subjects and stratified by clinical and sub clinical characteristics are needed to validate our findings.

Hypoxia promotes metastasis in human gastric cancer by up-regulating the 67-kDa laminin receptor

It has been reported that the 67-kDa laminin receptor (67LR) is implicated in cancer metastasis. We recently showed that 37LRP, the 67LR precursor, is a hypoxia-inducible factor 1 (HIF-1) target gene exposed to hypoxia in gastric cancer. Here, we investigated the role of 67LR in hypoxic metastasis and invasion in gastric cancer. Immunohistochemical analysis, western blotting, and RT-PCR assays revealed that 67LR was highly expressed in metastatic gastric cancers in vivo. Knockdown of the 67LR protein by RNA interference significantly decreased the adhesive, invasive, and in vivo metastatic abilities of the gastric cancer cell lines SGC7901 and MKN-45. Western blot analysis showed that 67LR increased the expression of urokinase-type plasminogen activator (uPA) and matrix metalloproteinase (MMP)-9, and decreased tissue inhibitor of matrix metalloproteinase (TIMP)-1 protein. We further showed that hypoxia induced 67LR expression in a time-dependent manner and this induction was inhibited by HIF-1 small-interfering (si) RNA. Both ERK and JNK inhibitors significantly inhibited hypoxia-induced expression of 67LR and the subsequent expression of uPA and MMP 9. SiRNA against 67LR or antibody against MMP9 and uPA significantly inhibited hypoxia-induced in vitro invasive ability. Taken together, these results reveal that 67LR promotes the invasive and metastatic ability of the gastric cancer cells through increasing uPA and MMP 9 expression, with involvement of the ERK and JNK signal pathway in hypoxia-induced 67 LR expressions and subsequent uPA and MMP9 expression.

Inhibition of the p53-MDM2 interaction by adenovirus delivery of ribosomal protein L23 stabilizes p53 and induces cell cycle arrest and apoptosis in gastric cancer

BACKGROUND

Inhibiting MDM2 activity in tumors that express wild-type (wt) p53 but have high levels of MDM2 protein has been considered an attractive anticancer strategy for many years. Previous studies revealed that human ribosomal protein L23 (RPL23) inhibited MDM2-mediated p53 degradation and thus induced p53 levels as well as its activity, suggesting that it might be a candidate for use as a gene therapy for cancer. In the present study, we evaluated whether targeting this pathway could be of therapeutic value against human gastric carcinoma.

METHODS

Gastric cancer cell lines carrying wt or mutant p53 gene were infected with adenovirus expressing RPL23 (Ad-RPL23). Cell growth assay, flow cytometry assay and morphology were used to observe the effects of Ad-RPL23 infection on tumor cells, and further, the effect of Ad-RPL23 treatment on tumor growth in vivo was investigated.

RESULTS

In vitro, adenovirus-mediated RPL23 gene transfer stabilized wt p53 by inhibiting its degradation, and thus resulted in G(1)-S cell cycle arrest and/or apoptosis of human gastric cancer MKN45 and AGS cells carrying wt p53 gene. Adenovirus-mediated RPL23 gene transfer also inhibited the growth of MKN45 tumors in subcutaneous mouse models.

CONCLUSIONS

The data obtained in the present study suggest that, through the inhibition of the p53-MDM2 interaction, adenovirus delivery of RPL23 can inhibit the proliferation of gastric cancer cells harboring wt p53 in vitro and in vivo. Exogenous RPL23-induced wt p53 stabilization and activation may be a novel therapeutic approach for patients with gastric cancer.

Manufacturing of 50 kA superconducting transformer for ITER correction coil conductor test

To meet the specifications of International Thermonuclear Experimental Reactor correction coil (CC) conductor, a 50 kA superconducting transformer has been designed and manufactured to provide the short sample of the CC conductor the current. The transformer consists of two concentric layer-wound superconducting solenoids with the primary inside the secondary coil. In order to test the transformer, the two legs of the secondary coil were directly connected by superconducting cables. A 500 W/4.5 K refrigerator was used to provide the supercritical helium. The maximum current of 56.3 kA in the secondary coil loop was obtained.

The rag locus of Porphyromonas gingivalis might arise from Bacteroides via horizontal gene transfer

Porphyromonas gingivalis is regarded as one of the risk factors of periodontitis. P. gingivalis exhibits a wide variety of genotypes. Many insertion sequences (ISs), located in their chromosomes, made P. gingivalis differentiate into virulent and avirulent strains. In this research, we investigated the prevalence of P. gingivalis in the gingival crevicular fluid (GCF) among periodontitis patients from Zhenjiang, China, detected the P. gingivalis rag locus distributions by multiplex polymerase chain reaction (PCR), and analyzed the origin of the P. gingivalis rag locus based on evolution. There were three rag locus variants co-existing in Zhenjiang. The results showed that the rag locus may be associated with severe periodontitis. This work also firstly ascertained that the rag locus might arise, in theory, from Bacteroides sp. via horizontal gene transfer.

Single-center experience of 253 portal vein thrombosis patients undergoing liver transplantation in China

OBJECTIVE

We sought to review the etiopathogenesis, diagnosis, and surgical options for 253 patients with portal vein thrombosis (PVT) undergoing orthotopic liver transplantation (OLT) to assess the the impact of PVT on outcomes.

METHODS

We retrospectively analyzed the data from 2508 adult patients undergoing 2614 OLTs in our center from September 1998 to July 2007. PVT was scored according to the operative findings and Yerdel grading of PVT. No prisoners were used as donors for this study.

RESULTS

Two hundred fifty-three patients were diagnosed with PVT (10.09%): there were 104 grade I; 114, grade II; 29, grade III; and 6, grade IV PVT. Sex and previous splenectomy increased the risk for PVT. In grade I and II cases, we performed simple thrombectomy, eversion thrombectomy, or improved eversion thrombectomy (IET, innovated by our center), producing smooth postoperative recoveries with a 0% in-hospitality mortality. In grade III cases, 18 underwent successful IET. Of 11 subjects who had eversion thrombectomy, six failed, and the distal superior mesentery vein or dilated splanchnic collateral tributary had to be used as the inflow vessel in four patients, and portal vein arterialization were performed in the other two patients, all of whom experienced a smooth postoperative recovery except one who died of hepatic failure and pulmonary infection 2 weeks after the operation. The in-hospitality mortality was 3.45%. In grade IV cases, three underwent successful IET, but another three cases failed, with two of them requiring a renal vein as the inflow vessel, and other one undergoing portocaval hemitransposition, with one postoperative death due to hepatic failure and another of cancer recurrence, an in-hospitality mortality rate of 33.33%. The transfusion requirement among PVT patients was significantly higher than that in non-PVT patients (9.32 +/- 3.12 U vs 6.02 +/- 2.40 U; P < .01). Blood loss in PVT patients who underwent the IET technique was significantly lower than that for an eversion thrombectomy (2800.36 +/- 930.52 mL vs 5700.21 +/- 162.50 mL P < .05). The overall actuarial 1-year survival rate in PVT patients was similar to the controls (86.56% vs 89.40%; P > .05).

CONCLUSION

OLT was successfully performed for PVT patients. The grade of PVT decided the surgical strategy. Similar 1-year survival rates were attained between PVT patients and controls undergoing OLT.

Ribosomal protein L6 promotes growth and cell cycle progression through upregulating cyclin E in gastric cancer cells

Our previous study revealed that human ribosomal protein L6 (RPL6) was upregulated in multidrug-resistant gastric cancer cells and over-expression of RPL6 could protect gastric cancer cells from drug-induced apoptosis. The present study was designed to explore the role of RPL6 in tumorigenesis and development of gastric cancer. The expression of RPL6 in gastric cancer tissues and normal gastric mucosa was evaluated by immunohistochemical staining. It was found RPL6 was expressed at a higher level in gastric cancer tissues than that in normal gastric mucosa. RPL6 was then genetically overexpressed or knocked down in human immortalized gastric mucosa epithelial GES cells. It was demonstrated that upregulation of RPL6 accelerated the growth and enhanced in vitro colony forming ability of GES cells whereas downregulation of RPL6 showed adverse effects. Moreover, over-expression of RPL6 could promote G1 to S phase transition of GES cells. It was further evidenced that upregulation of RPL6 resulted in elevated cyclin E expression while downregulation of RPL6 caused decreased cyclin E expression in GES cells. Taken together, these data indicated that RPL6 was overexpressed in human gastric cancer and its over-expression could promote cell growth and cell cycle progression at least through upregulating cyclin E expression.

Four types of potassium currents in motor nerve terminals of snake

The experiments were performed on transversus abdominis muscle of Elaphe dione by subendothelial recording. The results indicate that in snake motor nerve endings there exist four types of K(+) channels, i.e. voltage-dependent fast and slow K(+) channels, Ca(2+)-activated K(+) channel and ATP-sensitive K(+) channel. (i) The typical wave form of snake terminal current was the double-peaked negativity in standard solution. The first peak was attributed to Na(+) influx (I(Na)) in nodes of Ranvier. The second one was blocked by 3,4-aminopyridine (3,4-DAP) or tetraethylammonium (TEA), which corresponded to fast K(+) outward current (I(k.f)) through the fast K(+) channels in terminal part. (ii) After I(K.F) as well as the slow K(+) current (I(K.S)) were blocked by 3, 4-DAP, the TEA-sensitive Ca(2 +)-dependent K(+) current (I(K(Ca))) passing through Ca(2 +)-activated K(+) channel was revealed, whose amplitude depended on [K(+)](o) and [ca(2+) ](o). It was blocked by Ba(2+), Cd(2+) or Co(2+). (iii) I(K.F) and I(K(Ca)) were blocked by TEA, while I(K. S) was retained. It was sensitive to 3,4-DAP, partially blocked by ethanol (200 mmol/L) or beta-bungarotoxin (2 micromol/L), and enhanced by low pH (6.4-6.7). This is the first report that certain current component of motor nerve terminal is sensitive to pH in the range of 6. 4-7. 5. (iv) That diazoxide (200 micromol/L) increased the second negative peak and the effect was eliminated after further addition of glibenclamide (50 micromol/L) was taken as evidence for the presence of ATP-sensitive K(+) current (I(K.ATP)) at snake nerve terminal.

Peroxynitrite mediates glomerular lesion of diabetic rat via JAK/STAT signaling pathway

BACKGROUND

Peroxynitrite, a highly reactive oxidant produced by the reaction of nitric oxide with free radicals superoxide, has been indicated to be involved in many diseases. However, the contributions of peroxynitrite to diabetic nephropathy and the underlying mechanism have not been fully explored.

AIM

The present study was designed to evaluate the role and the underlying mechanism of peroxynitrite in glomerular lesion of diabetic rat.

METHODS

Diabetes was induced in male Wistar rats by i.p. injection of streptozotocin, and urate was used as a specific scavenger of peroxynitrite; the pathological changes of rat glomerulus were evaluated by hematoxylin and eosin, periodic acid-Schiff staining and transmission electron microscopy observation; immunohistochemistry and Western blot were used to detect the content of nitrotyrosine (the marker of peroxynitrite) in renal cortex; the expression levels of tyrosine phosphorylation of JAK2, STAT1, and STAT3 were assessed by Western blot assay; RT-PCR and Western blot were used to assay expression levels of transforming growth factor (TGF)-beta1 and fibronectin; biochemical indicators of renal function were also detected.

RESULTS

The content of nitrotyrosine was increased, consistent with the pathological changes of glomerulus and renal dysfunction in the diabetes group. Urate prevented the formation of nitrotyrosine in rat glomerulus and attenuated the pathological alterations. Furthermore, urate inhibited the activation of JAK2, STAT1, and STAT3. Finally, homogenates from renal cortices demonstrated reduced expression of TGF- beta1 and fibronectin under urate treatment.

CONCLUSIONS

Our findings thus provides in vivo evidence that exaggerated peroxynitrite formation mediates the glomerular lesion in, at least, Type 1 diabetes, which may function through JAK/STAT signaling pathway.