Critical role of TRPC6 channels in G2 phase transition and the development of human oesophageal cancer

BACKGROUND

Oesophageal squamous cell carcinoma (OSCC) is one of the leading causes of cancer-related death worldwide. However, the mechanism by which the OSCC develops remains largely unknown. Ion channels are important for cancer development. Whether the transient receptor potential canonical (TRPC), known as the non-selective cation channels, plays a role in OSCC development is unknown.

METHODS

The expression of TRPC6, a member of TRPC subfamily, was examined in samples from patients with OSCC by immunostaining and in situ hybridisation. The effects of TRPC6 channels on OSCC cell cycle progression, cell growth and in vivo tumour formation were investigated. The functional TRPC6 channels were found in OSCC cells by electrophysiology and Ca(2+) imaging analysis.

RESULTS

The expression of TRPC6 at protein and mRNA levels was markedly increased in human OSCC specimens than that in normal human oesophageal tissues. Blockade of TRPC6 channels in human OSCC cells inhibited elevation of intracellular Ca(2+) concentration ([Ca(2+)](i)) and activation of Cdc2 kinase. Meanwhile, the OSCC cell cycle was arrested at G2 phase and the cell growth was suppressed. Furthermore, inhibition of TRPC6 channels suppressed in nude mice the tumour formation generated by injection of the OSCC cells.

CONCLUSION

TRPC6 channels play a critical role in the development of OSCC. The [Ca(2+)](i) elevation regulated by TRPC6 channels is essential for G2 phase progression and OSCC development. These channels might be a novel target for therapeutic intervention of OSCC.

High mobility group box 1 as a mediator of endotoxin administration after hemorrhagic shock-primed lung injury

High mobility group box 1 (HMGB1) was discovered as a novel late-acting cytokine that contributes to acute lung injury (ALI). However, the contribution of HMGB1 to two-hit-induced ALI has not been investigated. To examine the participation of HMGB1 in the pathogenesis of ALI caused by the two-hit hypothesis, endotoxin was injected intratracheally in a hemorrhagic shock-primed ALI mouse model. Concentrations of HMGB1 in the lung of the shock group were markedly increased at 16 h (1.63 +/- 0.05, compared to the control group: 1.02 +/- 0.03; P < 0.05), with the highest concentration being observed at 24 h. In the sham/lipopolysaccharide group, lung HMGB1 concentrations were found to be markedly increased at 24 h (1.98 +/- 0.08, compared to the control group: 1.07 +/- 0.03; P < 0.05). Administration of lipopolysaccharide to the hemorrhagic shock group resulted in a notable HMGB1 increase by 4 h, with a further increase by 16 h. Intratracheal lipopolysaccharide injection after hemorrhagic shock resulted in the highest lung leak at 16 h (2.68 +/- 0.08, compared to the control group: 1.05 +/- 0.04; P < 0.05). Compared to the hemorrhagic shock/lipopolysaccharide mice, blockade of HMGB1 at the same time as lipopolysaccharide injection prevented significantly pulmonary tumor necrosis factor-alpha, interleukin-1beta and myeloperoxidase. Lung leak was also markedly reduced at 16 h; blockade of HMGB1 24 h after lipopolysaccharide injection failed to alter lung leak or myeloperoxidase at 48 h. Our observations suggest that HMGB1 plays a key role as a late mediator when lipopolysaccharide is injected after hemorrhagic shock-primed ALI and the kinetics of its release differs from that of one-hit ALI. The therapeutic window to suppress HMGB1 activity should not be delayed to 24 h after the disease onset.

Prolonging microtubule dysruption enhances the immunogenicity of chronic lymphocytic leukaemia cells

Cytotoxic chemotherapies do not usually mediate the expression of an immunogenic gene programme in tumours, despite activating many of the signalling pathways employed by highly immunogenic cells. Concomitant use of agents that modulate and complement stress-signalling pathways activated by chemotherapeutic agents may then enhance the immunogenicity of cancer cells, increase their susceptibility to T cell-mediated controls and lead to higher clinical remission rates. Consistent with this hypothesis, the microtubule inhibitor, vincristine, caused chronic lymphocytic leukaemia (CLL) cells to die rapidly, without increasing their immunogenicity. Protein kinase C (PKC) agonists (such as bryostatin) delayed the death of vincristine-treated CLL cells and made them highly immunogenic, with increased stimulatory abilities in mixed lymphocyte responses, production of proinflammatory cytokines, expression of co-stimulatory molecules and activation of c-Jun N-terminal kinase (JNK), p38 and nuclear factor kappa B (NF-kappaB) signalling pathways. This phenotype was similar to the result of activating CLL cells through Toll-like receptors (TLRs), which communicate 'danger' signals from infectious pathogens. Use of PKC agonists and microtubule inhibitors to mimic TLR-signalling, and increase the immunogenicity of CLL cells, has implications for the design of chemo-immunotherapeutic strategies.

Predictive values of clinical and pathological parameters for malignancy of gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) possess a wide spectrum of biological properties, from indolent to highly aggressive. In this study, we evaluated a set of clinical and pathological parameters for their predicative values for malignancy of GISTs by retrospective reviews of tumor specimens and their relevant medical records from 840 patients. All GIST cases were first assigned as malignant if they met any of the following criteria: gross spreads, including liver metastassis and/or peritoneal dissemination, microscopic spreads, including lymph node metastasis, infiltrations to vascular, fat, nerve and muscularis mucosal tissues, or relapse. The remaining cases were recorded as biological behavior uncertain. This initial assignment revealed a set of five morphological features to be associated with malignancy. They were: mitotic counts greater than 10 per 50HPFs (P<0.0001), muscularis propria infiltration (P<0.0001), coagulative necrosis (P<0.0001), perivascular growth pattern (P=0.005), and severe nuclear atypia (P=0.014). Therefore, a new classification system, including criteria of 2 gross spreads, 5 microscopic spreads, and 5 histopathological parameters was developed. All the GIST cases were re-classified into a group of 485 malignant tumors, and a group of 355 nonmalignant tumors. Patient follow-up data revealed 5-year disease-free and overall survival rates as high as 99.3% and 100% for the nonmalignant group, but low rates of 43.9% and 59.7% for the malignant group. These results demonstrated a correlation of the new classification with clinical outcomes. Therefore, this set of 12 parameters has predictive values for malignancy of GISTs, and is potentially useful in the grading of the tumors.

Farnesyltransferase inhibitors as radiation sensitizers

PURPOSE

The inhibition of activated Ras combined with radiotherapy was identified as a potential method for radiosensitization.

MATERIALS AND METHODS

Immunoblotting was used to control for prenylation inhibition of the respective Ras isoforms and for changes in activity of downstream proteins. Clonogenic assays with human and rodent tumour cell lines and transfected cell lines served for the testing of radiosensitivity. Xenograft tumours were treated with farnesyl transferase inhibitors and radiation and assayed for ex vivo plating efficiency, regrowth of tumours and EF5 staining for detection of hypoxia. Concurrent treatment with L-778,123 and radiotherapy was performed in non-small cell lung cancer (NSCLC) and head and neck cancer (HNC) patients.

RESULTS

Blocking the prenylation of Ras proteins in cell lines with Ras activated by mutations or receptor signalling resulted in radiation sensitization in in vitro and in vivo. The PI3 kinase downstream pathway was identified as a contributor to Ras-mediated radiation resistance. Additionally, increased oxygenation of xenograft tumours was observed after FTI treatment. Combined treatment in a phase I study was safe and effective in NSCLC and HNC.

CONCLUSIONS

Tumour cells with activated Ras were sensitized to radiation. Unravelling the underlying mechanisms promises to lead to even more specific drugs with higher potency and safety.

Src kinase Hck association with the WASp and mDia1 cytoskeletal regulators promotes chemoattractant-induced Hck membrane targeting and activation in neutrophils

The haemopoietic cell kinase (Hck) plays an important but poorly understood role in coupling chemoattractant stimuli to the actin cytoskeletal rearrangement required for neutrophil polarization and chemotaxis. Here, we show that Hck coimmunoprecipitates with the cytoskeletal regulatory Wiskott-Aldrich syndrome protein (WASp) and mammalian diaphanous-related formin 1 (mDia1) in chemoattractant-stimulated neutrophils, and that the 3 proteins inducibly colocalize with one another at the leading edge of chemotaxing cells. Hck interaction with WASp was found to be mediated by the Hck SH3 domain binding to the WASp proline-rich region, while Hck interaction with mDia1 was indirect but was required for binding to WASp. In contrast to wild-type cells, both WASp- and mDia1-deficient neutrophils showed severe impairment of chemokine-induced Hck membrane translocation and induction of Hck binding to WASp, and Hck activation and WASp tyrosine phosphorylation were impaired in mDia1-/- cells. Thus, chemotactic stimulation appears to induce an mDia1/Hck/WASp complex required for Hck membrane targeting and for induction of the Hck-mediated WASp tyrosine phosphorylation thought to be required for WASp-driven actin polymerization. These findings reveal that Hck functions in neutrophils to be realized, at least in part, via its interaction with mDia1 and WASp, and identifies the mDia1/Hck/WASp axis as a cytoskeletal signaling interface linking tyrosine phosphorylation to chemotactic and, possibly, other actin-based neutrophil responses.

The role of EGFR MAbs C225 in breast cancer stem cells

e22093

Background: The epithermal growth factor receptor(EGFR) signaling pathways has been implicated in self-renewal of breast cancer stem cells. It has been proved that the EGFR tyrosine kinase inhibitor-gefitinib significantly decreased the mammosphere- forming efficiency(MFE) in ductal carcinoma in situ (DCIS) derived cancer cells. We investigated the response of breast cancer stem cells in breast cancer cell line MCF-7 to EGFR MAbs C225(cetuximab). Methods: Cells were used for nonadherent (i.e.,mammosphere) culture and were divided into four groups according to the different culture medium whether or not including exogenous EGF and MAbs C225. MFE was calculated as the number of mammospheres (≥60um) and was expressed as a percentage. We Compared the percentage of CD44+/CD24- cells from the four groups, and measured the levels of the Wnt and Notch-3 gene expression of the four groups. Results: There was no significant difference of MFE between groups. In the presence of exogenous EGF, MAbs C225 significantly decreased the MFE and the percentage of CD44+/CD24- cells of mammospheres compared with exogenous EGF alone(0.7% versus 1.5%, P < 0.001 and 4% versus 11%P < 0.001;respectively). In the absence of exogenous EGF, MAbs C225 aslo statistically decreased the MFE and the percentage of CD44+/CD24- cells of mammospheres compared with that of lacking exogenous EGF and MAbs C225(0.53% versus 1.3%,P = 0.003 and 9% versus 3%, P < 0.01;respectively). And we observed that the Notch-3 gene expression was compensativly increased in the two groups of addition of MAb C225. No significant differences of Wnt gene expression were observed between groups. Conclusions: EGFR MAbs C225 could disrupt mammoshpere formation and decrease the percentage of CD44+/CD24- cells of mammoshpere cells. The expression of Notch-3 is increased with the EGFR antagonistics in breast cancer stem cells.

No significant financial relationships to disclose.

Phase I study of chidamide (CS055/HBI-8000), a novel histone deacetylase inhibitor, in patients with advanced solid tumors and lymphomas

3529

Background: Chidamide (CS055/HBI-8000) is a new benzamide type of histone deacetylase (HDAC) inhibitor with low nanomolar activity against HDAC1, 2, 3 and 10. This Phase I study evaluated the safety and tolerability of chidamide in patients (pts) with advanced solid tumors and lymphomas. Methods: 31 pts with refractory or relapsed advanced solid tumors (22) and lymphomas (9) were enrolled in this study. Escalating doses of 5, 10, 17.5, 25, 32.5 and 50 mg Chidamide (each with 3 to 7 pts) were administered orally either twice or three times per week for 4 consecutive weeks every 6 weeks. Results: No dose limiting toxicities (DLTs) were identified in the 2 x per week cohorts (22 pts) up to 50 mg; G2 and G3 hematological toxicities (leukopenia/neutropenia and thrombocytopenia) were observed at 50 mg. DLTs were reported as G3 diarrhea or vomiting in 2 pts in the 3 x per week cohort at 50 mg. Common adverse events were G1/G2, fatigue (n = 11), thrombocytopenia (n = 9), anorexia (n = 8), nausea/vomiting (n = 7), leukopenia/neutropenia (n = 6), hypochromia (n = 6), and diarrhea (n = 5). No cystitis, pericarditis, pericardial effusion or prolonged QTc intervals were observed. Single dose PK analysis in pts with 25, 32.5 and 50 mg revealed T1/2 of 16.8–18.3 h, Tmax of 1–2 h in most cases, and a dose-related increase in Cmax and AUC. Multiple dose PK analysis in pts with 32.5 mg 3 x per week suggested drug accumulation with this regimen. Significant induction of histone (H3) acetylation was observed in peripheral white blood cells, which lasted for 2–3 days in most pts after single dosing. 25 pts with total treatment cycles of 49 (range 1–6) were evaluable for efficacy. 4 pts with T-cell lymphomas (4/5 evaluable) and 1 pt with submandibular adenoid cystic carcinoma achieved PR, and 11 pts (2 B-cell lymphomas and 9 solid tumors) experienced SD. Conclusions: Chidamide was well-tolerated in pts with advanced solid tumors and lymphomas in the tested regimens. In addition, the compound exhibited a relatively long half-life, a long-lasting biomarker response and encouraging antitumor activity at well-tolerated doses. The overall phase I results recommend the 2 x per week regimen for phase II studies.

[Table: see text]

Expression of CD24 as a predictor of prognosis of hepatocellular carcinoma after operation

e22043

Background: CD24 expression has previously been reported in hepatocellular carcinoma (HCC), although little is known about its prognostic significance. The aim of this study is to evaluate the relation of CD24 expression and its prognostic significance in HCC. Methods: CD24 expression in stepwise metastatic HCC cell lines and tumor tissues from 50 HCC patients was investigated by quantitative real-time reverse transcription-PCR and Western blot analyses. The role of CD24 was investigated by depletion CD24 expression in HCC cells through small-interfering RNA. Tumor tissue microarrays of 314 HCC patients who underwent resection between 1997 and 2000 were used to detect the expressions of CD24, β-catenin and PCNA expression. The prognostic significance was assessed using Kaplan-Meier survival estimates and log-rank tests. Results: CD24 was overexpressed in the high metastatic HCC cell line and in tumor tissues of recurrent patients. Depletion of CD24 caused a notable decrease in cell proliferation, migration and invasiveness in vitro. CD24 was confirmed as an independent predictor for overall survival (p<0.001) and relapse-free survival (p<0.001), regardless of recurrence time, AFP level, TNM stage and Edmondson stage. High expression of CD24 in HCC tissues was significantly associated cytoplasmic/nuclear accumulation of β-catenin (p=0.023), high tumor proliferate status (p=0.018) and diffused intrahepatic recurrence and distance metastasis (p=0.026). Adjuvant TACE after operation reduced the early recurrence (≤1 year) in CD24+ HCC patients (p=0.024), while there had no significant changes in CD24- patients (p=0.284). Conclusions: High expression levels of CD24 were related with high invasive and metastatic potential, high tumor proliferation status and activation of Wnt/β-catenin pathway. The expression of CD24 provides new prognostic information about HCC prognosis and targeted therapy to CD24+fraction in HCC may comprise a promising anti-recurrence strategy for HCC patients after surgery.

No significant financial relationships to disclose.

The mDial formin is required for neutrophil polarization, migration, and activation of the LARG/RhoA/ROCK signaling axis during chemotaxis

Neutrophil chemotaxis depends on actin dynamics, but the roles for specific cytoskeleton regulators in this response remain unclear. By analysis of mammalian diaphanous-related formin 1 (mDia1)-deficient mice, we have identified an essential role for this actin nucleator in neutrophil chemotaxis. Lack of mDia1 was associated with defects in chemoattractant-induced neutrophil actin polymerization, polarization, and directional migration, and also with impaired activation of RhoA, its downstream target p160-Rho-associated coil-containing protein kinase (ROCK), and the leukemia-associated RhoA guanine nucleotide exchange factor (LARG). Our data also revealed mDia1 to be associated with another cytoskeletal regulator, Wiskott-Aldrich syndrome protein (WASp), at the leading edge of chemotaxing neutrophils and revealed polarized morphology and chemotaxis to be more mildly impaired in WAS(-/-) than in mDia1(-/-) neutrophils, but essentially abrogated by combined mDia1/WASp deficiency. Thus, mDia1 roles in neutrophil chemotaxis appear to be subserved in concert with WASp and are realized at least in part by activation of the LARG/RhoA/ROCK signaling pathway.

Data acquisition system using six degree-of-freedom inertia sensor and ZigBee wireless link for fall detection and prevention

Fall detection and prevention require logged physiological activity data of a patient for a long period of time. This work develops a data acquisition system to collect motion data from multiple patients and store in a data base. A wireless sensor network is built using high precision inertia sensors and low power Zigbee wireless transceivers. Testing results prove the system function properly. Researchers and physicians can now retrieve and analyze the accurate data of the patient movement with ease.

Hypoxia-mediated up-regulation of MGr1-Ag/37LRP in gastric cancers occurs via hypoxia-inducible-factor 1-dependent mechanism and contributes to drug resistance

Our previous study demonstrated hypoxia-inducible factor-1(HIF-1) could prompt multidrug resistance (MDR) phenotype and MGr1-Ag/37LRP, a novel drug-resistance protein was reported by our labortary, associated with multidrug resistance in gastric cancer. Given this association, we hypothesized that MGr1-Ag/37LRP contributed to HIF-1-dependent hypoxia-induced MDR phenotype. Initial experiments revealed that blocking MGr1-Ag/37LRP expression by siRNA in gastric cancer cells effectively reversed multidrug resistance phenotype induced by hypoxia. Subsequent analysis of MGr1-Ag/37LRP mRNA and protein in gastric cancer cells revealed a time-dependent manner increase with hypoxia. While the up-regulation of MGr1-Ag/37LRP was abolished by HIF-1 inhibition with siRNA. Studies using luciferase promoter constructs revealed a significant increase in activity in cells subject to hypoxia and such hypoxia inducibility was lost in cells co-transfected siRNA targeting HIF-1. Analysis of the MGr1-Ag/37LRP promoter revealed several potential binding sites for HIF-1. Electrophoretic mobility shift assay and chromatin immunoprecipitation demonstrated a functional HIF-1 binding site within MGr1-Ag/37LRP gene regulatory sequence located at -16 to -11 relative to the transcriptional initiation point. These observations demonstrate that MGr1-Ag/37LRP is actively engaged by hypoxia and represent a novel HIF-1 target. Such results suggest hypoxia-elicited MGr1-Ag/37LRP expression as a pathway for resistance of gastric cancer to chemotherapeutics.

Assessment of mitral valve volume by quantitative three-dimensional echocardiography in patients with rheumatic mitral valve stenosis

BACKGROUND

Thickening of mitral leaflets in rheumatic mitral valve stenosis is well described in necropsy studies; however, volume computation of the thickening mitral leaflets has not been attempted. 4trial fibrillation is one of the complications of rheumatic mitral stenosis. Quantitative assessment of thickened mitral valve and its relation to clinical complications is clinically desirable.

HYPOTHESIS

The study was undertaken to compare measurement of mitral valve volume in normal subjects and in patients with rheumatic mitral valve stenosis.

METHODS

An HP Sonos 2500 echocardiographic system with 5 MHz multiplane transesophageal transducer was used for data acquisition, and TomTec Echoscan computer setup was used to off-line volume computation. Study subjects included 10 normal subjects (mean age 44.8 years) and 36 patients with rheumatic mitral valve stenosis (22 female, 14 male) with an age range of 25 to 69 years (mean age 47 +/- 9.6 years). Mitral valve volumes were compared between the normal subjects and patients with mitral valve stenosis, and further comparison was made between the sinus rhythm (SR) and atrial fibrillation (AF) groups in patients with mitral valve stenosis. In all study subjects, the mitral valve area (MVA) was determined by two-dimensional echocardiography.

RESULTS

Quantitative three-dimensional (3-D) echocardiography showed that mitral valve volume was significantly larger in patients with mitral valve stenosis than in normal subjects (9.0 +/- 2.2 and 4.5 +/- 0.7 ml, respectively, p < 0.001). When patients with mitral valve stenosis were divided into the SR and AF groups, mitral valve volume was found to be significantly larger in the AF group than in the SR group (9.76 +/- 2.2 ml. and 7.72 +/- 1.5 ml, respectively, p < 0.01) and patients in the AF group tended to be older (p < 0.05) with larger left atrial diameter (LAD) (p < 0.01). However, MVA between the two groups showed no statistical significance (1.1 +/- 0.43 and 1.0 +/- 0.34 cm2, respectively, p > 0.2). When the study subjects were divided into two groups (< 50 and > or = 50 years) according to age, the comparison of mitral valve volume between these two groups (9.37 +/- 2.18 and 8.56 +/- 2.14 ml, p > 0.2) showed no statistical significance.

CONCLUSIONS

Quantitative 3-D echocardiography can be applied for the measurement of mitral valve volume in vivo. Patients with rheumatic mitral valve stenosis with atrial fibrillation have a propensity to have a larger mitral valve volume and are older than the patients with sinus rhythm; however, the age per se does not seem to be a cause for larger mitral valve volume.

Analysis of 10 independent samples provides evidence for association between schizophrenia and a SNP flanking fibroblast growth factor receptor 2

We and others have previously reported linkage to schizophrenia on chromosome 10q25-q26 but, to date, a susceptibility gene in the region has not been identified. We examined data from 3606 single-nucleotide polymorphisms (SNPs) mapping to 10q25-q26 that had been typed in a genome-wide association study (GWAS) of schizophrenia (479 UK cases/2937 controls). SNPs with P<0.01 (n=40) were genotyped in an additional 163 UK cases and those markers that remained nominally significant at P<0.01 (n=22) were genotyped in replication samples from Ireland, Germany and Bulgaria consisting of a total of 1664 cases with schizophrenia and 3541 controls. Only one SNP, rs17101921, was nominally significant after meta-analyses across the replication samples and this was genotyped in an additional six samples from the United States/Australia, Germany, China, Japan, Israel and Sweden (n=5142 cases/6561 controls). Across all replication samples, the allele at rs17101921 that was associated in the GWAS showed evidence for association independent of the original data (OR 1.17 (95% CI 1.06-1.29), P=0.0009). The SNP maps 85 kb from the nearest gene encoding fibroblast growth factor receptor 2 (FGFR2) making this a potential susceptibility gene for schizophrenia.

Insulin prevents latent skin lesions by inhibiting the generation of advanced glycation end products in streptozotocin-induced diabetic rats

The preventive effect of insulin on latent skin lesions in streptozotocin-induced diabetic rats was investigated. Diabetes was induced in 72 male Sprague-Dawley rats, with 36 rats serving as the control group. Half of the diabetic rats were treated with insulin, and the other half were injected with vehicle. Skin tissues were collected 4, 8, and 12 weeks after the initiation of insulin therapy for measurement of glucose, collagen-related fluorescence and advanced glycation end product (AGE) expression, and histological observation. The diabetic rats exhibited changes in skin tissue, including a decrease in thickness, disappearance of the multilayer epithelium structure, degeneration of collagen fibers, and an increase in the infiltration of inflammatory cells, in addition to a significant increase in blood glucose and AGE expression. These effects were greatly ameliorated by insulin therapy. Insulin therapy in early-stage diabetes mellitus prevents potential skin lesions, possibly by inhibiting AGE formation and inflammatory reactions following glycemic control.