Abstract 1357: Role of Natural Killer-cell Immunoglobulin-like receptors KIR2DL1 and KIR3DL1 in immune resistance

Background: The aim of this study is to investigate the mechanism of immune-escape and cancer metastasis by the natural killer (NK) cell immunoglobulin-like receptor (KIRs) subtypes (KIR2DL1 and KIR2DL1) in human lung cancer. We previously reported that metastatic cancer cells acquire immune-resistance by aberrantly expressing KIR on their surface (AACR 2009). In this project we forced expression two of KIR2DL1 and KIR3DL1 plasmids in some H2122-GFP parental lung cancer cells with null expression of KIR and investigated their function in conferring the immune-resistance against NK cell killing.

Method: KIR2DL1 (LL454) and KIR3DL1 (LL456) plasmids were transfected into Phoenix Retroviral Expression system. Virus containing media were used to infect target cells (H2122-GFP) for individual KIR subtype or both KIR subtype expression. Stable transformants were enriched by cell sorting. H2122-GFP parental cells and KIR expressing cells were exposed to various amounts of human normal NK cells or transformed NK-92MI cell line. Anti-proliferative effects by NK cells were accessed with fluorescence intensity in microplate reader. IC50 was determined based on the Effector (NK) / Target Ratio (ETR).

Result: Using cell sorting, single (2DL1 or 3DL1) or double (2DL1 and 3DL1) KIR expressing cells were separated into groups of low, medium and high level of KIR2DL1 or KIR3DL1 expression, based on their fluorescence intensity. When exposed to various amount of normal human NK cells, the parental line was most sensitive to NK killing with an IC50 ETR=2.2, followed by 2DL1-M (4.7), 3DL1-M (5.2), 2DL1-H (7.0), 3DL1-H (9.5), KIR2+ (10.1) and KIR3+(12). Interestingly, the transformed NK-92MI cell line seemed to be more effective than normal human NK cell in killing H2122-GFP and its derivatives and had down shifted the ETR by 10 fold. Nevertheless, the parental line was most sensitive to NK-92MI killing with an IC50 ETR = 0.23, followed by 2DL1-H (0.66), 3DL1-H (1.1), 3D/2DL1-L (1.5), KIR3+(1.8), 2D/3DL1-M (2.00), 2D/3DL1-L (2.20), 3D/2DL1-H (2.60), 3D/2DL1-M (2.90) and 2D/3DL1-H (3.0) respectively. Our data clearly demonstrated that forced expression of KIRs into lung cancer cells confers resistance to NK cytolytic killing and the degree of resistance increases progressively with the level of KIR expression. Double expression of both 2DL1 and 3DL1 in high level in lung cancer cells resulted in higher resistance than the metastatic KIR+3 line.

Conclusion: Aberrant expression of KIR, either by in vivo immune-selection or by forced expression, is responsible for conferring immune-resistance against NK cytolytic killing of human lung cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1357.

Combination of 2-methoxyestradiol (2-ME2) and eugenol for apoptosis induction synergistically in androgen independent prostate cancer cells

Lack of effective treatment options for the management of hormone refractory prostate cancer (PCA) reinforce the great need to develop novel compounds that act singly or in combination. 2-Methoxyestradiol (2-ME(2)) is an endogenous estrogenic metabolite that has been reported to work as an antiproliferative agent in various tumor models including prostate. Recently conducted clinical trial in hormone refractory prostate cancer (HRPC) patients concluded that 2-ME(2) was safe and well tolerated. However this study identified bioavailability of 2-ME(2) as a limiting factor. Here we report the ability of a combination of 2-ME(2) and eugenol (4-allyl-2-methoxyphenol) as an approach for enhancing anticancerous activities in prostate cancer cells. Combining 2-ME(2) with eugenol (i) inhibited growth of prostate cancer cells and induced apoptosis at lower concentrations than either single agent alone; (ii) analysis of the data using combination index (CI) showed CI values of 0.4 indicating strong synergistic interaction; (iii) increased population of cells G(2)/M phase by 4.5-fold (p=0.01); (iv) significantly reduced expression of antiapoptotic protein Bcl-2 and enhanced expression of proapoptotic protein Bax. Combination induced apoptosis was not affected in PC-3 cells that over-express or lack Bcl-2 but was associated with loss of mitochondrial membrane potential. Since 2-ME(2) was well tolerated in phase II trail in patients with HRPC; and eugenol is consumed by humans in the form of spices, the combination of 2-ME(2) with eugenol may offer a new clinically relevant treatment regimen. Combining these agents may allow ameliorating any adverse effects of either 2-ME(2) or eugenol alone by reducing their individual concentrations should these two agents be developed for human use.

Comparison of traditional and low sensitivity whiteners

This placebo-controlled, double-blind randomized clinical trial compared five 10% carbamide peroxide tooth whitening formulations. Three products contained varying concentrations of potassium nitrate as desensitizers. One contained no desensitizers and one was a placebo. During the two weeks of active bleaching, participants used a daily diary to record the number of days of sensitivity from hot, cold, gums, tongue and/or throat. The total number of days of sensitivity experienced by the participants in each group was compared. Participants using the agent with no desensitizers did not experience any more sensitivity than those using the agent containing 3% potassium nitrate. The products that included 0.5% potassium nitrate and 0.5% potassium nitrate and 0.25% sodium fluoride were not associated with any more sensitivity than the placebo group. In addition, the shade tab change from baseline to 11 weeks following cessation of bleaching was compared. Using an active bleaching agent, no difference in color change was noted among the four groups. All four groups were associated with significantly higher color change than the placebo. The addition of a small percentage of potassium nitrate to a 10% carbamide peroxide tooth whitener was shown to significantly reduce postoperative sensitivity without reducing efficacy.

Effect of weight loss on markers of triglyceride-rich lipoprotein metabolism in the metabolic syndrome

BACKGROUND

Hypertriglyceridaemia, a consistent feature of dyslipidaemia in the metabolic syndrome (MetS), is related to the extent of abdominal fat mass and altered adipocytokine secretion. We determined the effect of weight loss by dietary restriction on markers of triglyceride-rich lipoprotein (TRL) metabolism and plasma adipocytokines.

DESIGN

Thirty-five men with MetS participated in a 16 week randomized controlled dietary intervention study. Apolipoprotein (apo) C-III, apoB-48, remnant-like particle (RLP)-cholesterol, total adiponectin, high-molecular weight (HMW) adiponectin, and retinol-binding protein-4 (RBP-4) concentrations were measured using immunoassays.

RESULTS

Compared with weight maintenance (n = 15), weight loss (n = 20) significantly decreased body weight, plasma insulin, triglycerides, total cholesterol, low-density lipoprotein (LDL)-cholesterol and lathosterol (P < 0.05). Weight loss also decreased plasma concentrations of apoC-III (-33%), apoB-48 (-37%), very low-density lipoprotein (VLDL)-apoB (-43%), RLP-cholesterol (-48%), and RBP-4 (-20%), and significantly increased plasma total (+20%) and HMW-adiponectin (+19%) concentrations. In the weight loss group, reduction in plasma apoC-III was associated (P < 0.05) with reduction in plasma apoB-48, VLDL-apoB, RLP-cholesterol and triglycerides. Increase in total adiponectin was associated (P < 0.05) with the reduction in plasma VLDL-apoB and triglycerides. The changes in HMW-adiponectin and RBP-4 were not associated with changes in plasma apoB-48, apoC-III, VLDL-apoB, RLP-cholesterol or triglycerides. In multiple regression analysis including changes in visceral fat, insulin and total adiponectin concentrations, the fall in plasma apoC-III concentration was an independent predictor of the reductions in plasma apoB-48, VLDL-apoB, RLP-cholesterol and triglycerides concentrations.

CONCLUSIONS

In men with MetS, weight loss decreases the plasma concentrations of apoB-48, VLDL-apoB, RLP-cholesterol and triglycerides. This effect could partly relate to concomitant changes in plasma apoC-III and adiponectin concentrations that accelerate the catabolism of TRLs.

An ABC of apolipoprotein C-III: a clinically useful new cardiovascular risk factor?

BACKGROUND

Hypertriglyceridaemia, commonly found in subjects with obesity and type 2 diabetes mellitus, is associated with increased risk of coronary heart disease (CHD). Apolipoprotein C-III (apoC-III) plays an important role in regulating the metabolism of triglyceride-rich lipoproteins (TRLs) and may provide a new approach to assessing hypertriglyceridaemia.

AIMS

We review the role of apoC-III in regulating TRL metabolism and address the potential importance of apoC-III in clinical practice.

DISCUSSION

Hypertriglyceridaemia is chiefly a consequence of alterations in the kinetics of TRLs, including overproduction and delayed clearance of very-low density lipoprotein (VLDL). ApoC-III is an inhibitor of lipoprotein lipase and of TRLs remnant uptake by hepatic lipoprotein receptors. Elevated apoC-III, usually resulting from hepatic overproduction of VLDL apoC-III, may cause accumulation of plasma TRLs leading to hypertriglyceridaemia. The results from recent observational studies demonstrate that apoC-III is a strong predictor of risk for CHD, but this chiefly relates to apoC-III in apoB-containing lipoproteins. Lifestyle and pharmacological intervention can correct hypertriglyceridaemia by a mechanism of action that regulates apoC-III transport.

CONCLUSIONS

Targeting apoC-III metabolism may therefore be an important, new therapeutic approach to managing dyslipidaemia and CHD risk in obesity, insulin resistance and type 2 diabetes mellitus. However, further work is required to establish the practical aspects of measuring apoC-III in routine laboratory service and the precise therapeutic targets for serum total apoC-III and/or apoC-III in apoB-containing lipoproteins. While showing much promise as a potentially useful cardiovascular risk factor, apoC-III is not yet ready for prime time use in clinical practice.

Radiofrequency ablation after transarterial embolization as therapy for patients with unresectable hepatocellular carcinoma

PURPOSE

To evaluate the usefulness of transcatheter arterial embolization (TAE) followed by radiofrequency ablation (RFA) as combined treatment for unresectable hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

Thirty-six consecutive patients (cirrhosis, Child-Pugh class A or B) with solitary or oligonodular HCC were treated (41 lesions; mean size, 58.9 mm; range, 30-120 mm). RFA was performed after one TAE treatment. Local efficacy was evaluated with multiphasic computed tomography (CT) performed an average of two months after RFA and once during later follow-up.

RESULTS

The mean follow-up period was 16 months (range, 2-45 months). Technical success (namely, complete tumor devascularization during the arterial phase) was achieved for 59% of lesions at the first CT evaluation and for 46% at the second evaluation. Among prognostic factors included in the analysis, only lesion diameter (< 50 mm versus > or = 50 mm) was statistically significant in terms of predicting local success (Fisher's exact test: 85% versus 43% at first CT, p<0.01; 70% versus 36% during follow-up, p=0.05). There were no major periprocedural complications. Kaplan-Meier analysis showed survival rates of 84% at 12 months and 57% at 24 months.

CONCLUSIONS

Combined therapy--TAE then RFA--for unresectable HCC lesions in patients with cirrhosis produces a relatively high complete local response rate compared with TAE or RFA alone. Our results, considered with those from other case series, may help design prospective, randomized clinical trials to test combination therapy versus single-modality therapy in terms of risks and benefits.

Cross-talk between G Protein–Coupled Receptor and Epidermal Growth Factor Receptor Signaling Pathways Contributes to Growth and Invasion of Head and Neck Squamous Cell Carcinoma

G protein-coupled receptors (GPCR) and the epidermal growth factor receptor (EGFR) are often both overexpressed and contribute to the growth of cancers by activating autocrine pathways. GPCR ligands have been reported to trigger EGFR signaling via receptor cross-talk in cancer cells. Here, we show that GPCR ligands prostaglandin E2 (PGE2) and bradykinin (BK) activate EGFR signaling. Inhibition of EGFR using several strategies, including small-molecule inhibitors and an EGFR-specific antibody, resulted in partial attenuation of signaling downstream of EGFR. PGE2 and BK triggered EGFR signaling by increasing selective autocrine release of transforming growth factor-alpha (TGF-alpha). Inhibition of tumor necrosis factor-alpha-converting enzyme abrogated BK- or PGE2-mediated activation of EGFR signaling. Both PGE2 and BK stimulated head and neck squamous cell carcinoma (HNSCC) invasion via EGFR. Treatment of HNSCC cells with the BK antagonist CU201 resulted in growth inhibition. The combination of CU201 with the EGFR small-molecule inhibitor erlotinib resulted in additive inhibitory effects on HNSCC cell growth in vitro. Inhibition of the PGE2 synthesis pathway with sulindac induced HNSCC cytotoxicity at high doses (EC(50), 620 micromol/L). However, combined inhibition of both EGFR with the tyrosine kinase inhibitor erlotinib and GPCR with sulindac at low doses of 6 and 310 micromol/L, respectively, resulted in synergistic killing of HNSCC tumor cells. Combined blockade of both EGFR and GPCRs may be a rational strategy to treat cancers, including HNSCC that shows cross-talk between GPCR and EGFR signaling pathways.

Antitumor Activity of the Epidermal Growth Factor Receptor (EGFR) Tyrosine Kinase Inhibitor Gefitinib (ZD1839, Iressa) in Non–Small Cell Lung Cancer Cell Lines Correlates with Gene Copy Number and EGFR Mutations but not EGFR Protein Levels

PURPOSE

Recognition that the epidermal growth factor receptor (EGFR) was a therapeutic target in non-small cell lung cancer (NSCLC) and other cancers led to development of the small-molecule receptor tyrosine kinase inhibitors gefitinib and erlotinib. Clinical trials established that EGFR tyrosine kinase inhibitors produced objective responses in a minority of NSCLC patients. We examined the sensitivity of 23 NSCLC lines with wild-type or mutated EGFR to gefitinib to determine genes/proteins related to sensitivity, including EGFR and HER2 cell surface expression, phosphorylated EGFR expression, EGFR gene copy number, and EGFR mutational status. Downstream cell cycle and signaling events were compared with growth-inhibitory effects.

EXPERIMENTAL DESIGN

We determined gefitinib sensitivity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, EGFR expression by fluorescence-activated cell sorting and immunohistochemistry, phosphorylated EGFR by Western blotting, EGFR gene copy number by fluorescence in situ hybridization, and EGFR mutation by sequencing. The cellular effects of gefitinib on cell cycle were determined by flow cytometry and the molecular effects of gefitinib EGFR inhibition on downstream signal proteins by Western blotting. Gefitinib in vivo effects were evaluated in athymic nude mice bearing sensitive and resistant NSCLC xenografts.

RESULTS

There was a significant correlation between EGFR gene copy number, EGFR gene mutations, and gefitinib sensitivity. EGFR protein was necessary but not sufficient for predicting sensitivity. Gefitinib-sensitive lines showed a G(1) cell cycle arrest and inactivation of downstream signaling proteins; resistant cell lines had no changes. The in vivo effects mirrored the in vitro effects.

CONCLUSIONS

This panel of NSCLC lines characterized for gefitinib response was used to identify predictive molecular markers of response to gefitinib. Several of these have subsequently been shown to identify NSCLC patients likely to benefit from gefitinib therapy.

Comparison of clinical staging systems in predicting survival of hepatocellular carcinoma patients receiving major or minor hepatectomy

AIM

To compare the utility of seven commonly used staging systems in the prediction of survival among patients with hepatocellular carcinoma (HCC) undergoing major or minor hepatectomy.

METHODS

All patients were classified by the Okuda, the TNM, the CLIP, the BCLC, the CUPI, the JIS and the MELD classifications to estimate the probabilities of survival. Survival curves were calculated using the Kaplan-Meier method and were examined using log-rank testing. The overall predictive power for patient survival with each staging system was evaluated using linear trend chi(2) tests and from the area under the receiver operating characteristic (ROC) curve.

RESULTS

In our patient cohort, the log-rank test and the linear trend chi(2) test of the CLIP and JIS systems gave better results than did the other staging systems. The discriminatory ability of the CLIP and JIS staging for death, evaluated by ROC curve areas, was also better. In the subgroups of major hepatectomy patients with a non-cirrhotic liver or minor hepatectomy patients with a cirrhotic liver, the CLIP and JIS systems showed similar better performances in these three tests. The discriminatory ability of the CLIP system was the best in major hepatectomy patients with a non-cirrhotic liver while JIS score discriminated best in minor hepatectomy patients with a cirrhotic liver.

CONCLUSION

Among the seven staging systems, the CLIP and JIS systems perform better than do the others. While the CLIP system should be considered to stage major hepatectomy patients, the JIS system could be chosen to stage minor hepatectomy patients.

Fish oils, phytosterols and weight loss in the regulation of lipoprotein transport in the metabolic syndrome: lessons from stable isotope tracer studies

1. Dyslipoproteinaemia is a cardinal feature of the metabolic syndrome that accelerates atherosclerosis. It is characterized by high plasma concentrations of triglyceride-rich and apolipoprotein (apo) B-containing lipoproteins, with depressed concentrations of high-density lipoprotein (HDL). Dysregulation of lipoprotein metabolism in these subjects may be due to a combination of overproduction of very-low density lipoprotein (VLDL) apoB-100, decreased catabolism of apoB-containing particles and increased catabolism of HDL apoA-I particles. 2. Nutritional interventions may favourably alter lipoprotein transport in the metabolic syndrome. We review our collaborative studies, using stable isotopes and compartmental modelling, of the kinetic effects of fish oils, plant sterols (phytosterols) and weight reduction on the dyslipoproteinaemia in this disorder. 3. Fish oil supplementation diminished hepatic secretion of VLDL-apoB and enhanced conversion of VLDL to low-density lipoprotein (LDL)-apoB, without altering catabolism. 4. Plant sterols (phytosterols) did not have a significant effect on plasma concentrations of lipids and lipoprotein or the kinetics of apoB and apoA-I. 5. Modest weight reduction optimally decreased plasma triglyceride and LDL-cholesterol via reduction in hepatic apoB secretion and reciprocal upregulation of LDL catabolism. 6. The scope and potential of future studies using stable isotope tracers is discussed.

Measurement of liver fat by magnetic resonance imaging: Relationships with body fat distribution, insulin sensitivity and plasma lipids in healthy men

AIM

We compared the use of magnetic resonance imaging (MRI) as a test for liver fat content (LFAT) with proton magnetic resonance spectroscopy (MRS) and investigated its relationship with body fat distribution, insulin sensitivity, plasma lipids and lipoproteins.

METHODS

LFAT was quantified by MRI and MRS in 17 free-living, healthy men with a wide range of body mass indexes. Fasting adiponectin was measured by immunoassay and insulin resistance by homeostasis assessment (HOMA) score. Intraperitoneal, retroperitoneal, anterior subcutaneous and posterior subcutaneous abdominal adipose tissue masses (ATMs) were determined by MRI.

RESULTS

Measurements of LFAT by MRI and MRS were highly correlated (r = 0.851, p < 0.001). In univariate regression analysis, LFAT by MRI was also significantly correlated with plasma triglycerides (TGs), insulin, HOMA score, carbohydrate intake and the masses of all abdominal adipose tissue compartments (p < 0.05). LFAT was inversely correlated with plasma adiponectin (r = -0.505, p < 0.05). In multivariate linear regression analysis including plasma adiponectin and age, intraperitoneal ATM was an independent predictor of LFAT (beta-coefficient = 0.587, p = 0.024). Moreover, intraperitoneal ATM was also an independent predictor of HOMA score after adjusting for LFAT, plasma adiponectin and age (beta-coefficient = 0.810, p = 0.010). Conversely, LFAT was a significant predictor of plasma TG concentration after adjusting for adiponectin, intraperitoneal ATM, HOMA and age (beta-coefficient = 0.751, p = 0.007). Similar findings applied with LFAT measured by MRS.

CONCLUSIONS

These data suggest that MRI is as good as MRS to quantify liver fat content. Our data also suggest that liver fat content could link intraabdominal fat with insulin resistance and dyslipidaemia.

High-density lipoprotein apolipoprotein A-I kinetics: comparison of radioactive and stable isotope studies

To compare the kinetic determinants of high-density lipoprotein (HDL) apolipoprotein A-I (apoA-I) concentration in lean normolipidaemic subjects using radioisotope and stable isotope studies. We pooled data from 16 radioisotope and 13 stable isotope studies to investigate the kinetics of apoA-I in lean normolipidemic individuals. We also examined the associations of HDL kinetic parameters with age, sex, body mass index (BMI) and concentrations of apoA-I, triglycerides, HDL cholesterol and low-density lipoprotein (LDL) cholesterol. Lean subjects from radioisotope and stable isotope studies were matched for age, gender, BMI and lipid profile. The apoA-I concentration was significantly lower in the radioisotope group than the stable isotope group (P = 0.031). There was no significant difference in HDL apoA-I fractional catabolic rate (FCR) and production rate (PR) between the groups. In the radioisotope group, HDL apoA-I FCR was significantly associated with apoA-I and HDL cholesterol concentrations (r = -0.681, P < 0.001 and r = -0.542, P < 0.001, respectively), whereas in the stable isotope group, only HDL apoA-I PR was significantly associated with apoA-I concentration (r = 0.455, P = 0.004). Our findings suggest that HDL apoA-I FCR is the primary determinant of apoA-I concentrations in lean subjects in studies using radiotracer techniques. By contrast, HDL apoA-I PR is the primary determinant of apoA-I concentration in lean subject in studies employing stable isotope methods. These discrepancies may be reconciled by differences in methodologies and/or study population characteristics.

Performance of 2 packable composites at 12 months

OBJECTIVE

The purpose of this randomized, double-blind, clinical trial was to compare the marginal seal of 2 packable resin composite materials in moderate to large lesions on molars.

METHOD AND MATERIALS

Fifty participants in need of a moderate to large Class 2 or complex Class 1 molar restoration were randomly distributed into 4 groups, to receive either Alert (Jeneric/Pentron) or SureFil (Dentsply/Caulk) resin composite with or without a surface sealer. Each participant received one restoration. With the exception that study protocol limited increments to no more than 4 mm, teeth were restored according to the manufacturers' instructions, and surface sealer was applied after finishing in the designated groups. Use of Alert includes routine placement of a flowable composite liner. Clinical performance of the restorations was evaluated in 8 categories at baseline, 6 months, and 12 months. The 2 materials were compared to determine if a difference in marginal seal existed between groups. The number of restorations exhibiting marginal staining was compared using Fischer's exact test at a significance level of 5%.

RESULTS

Six participants did not present for the 12-month recall. At 12 months, 19 (90.5%) Alert restorations and 15 (68.2%) SureFil restorations did not exhibit marginal staining. There was no statistically significant difference between the 2 restorative materials for marginal staining. Overall, 3 restorations were rated as failures.

CONCLUSION

At 12 months, materials placed with a flowable liner were not associated with a significant reduction in marginal staining.

Apolipoproteins as markers and managers of coronary risk

Coronary artery disease (CAD) is a major cause of morbidity and mortality in Western communities. Reliable indices of coronary risk assessment and targets for drug treatment are important to the management of patients. Although plasma LDL cholesterol is well established as a predictor of CAD, it may not be the best circulatory marker. Results from recent epidemiological studies and statin trials suggest that apolipoprotein B-100 (apoB), with or without apoA-I, is superior to LDL cholesterol in predicting coronary events. Measurements of apolipoproteins are internationally standardized, automated, cost-effective and more convenient and precise than those for LDL cholesterol. ApoB may also be preferable to the measurement of non-HDL cholesterol. Measurement of apolipoproteins (apoB and possibly apoA-I) should be routinely added to the routine lipid profile (cholesterol, triglycerides and high-density lipoprotein cholesterol) to assess the atherogenic potential of lipid disorders. This is particularly relevant to dyslipidaemias characterized by an elevation in plasma triglycerides. Apolipoproteins, especially apoB, could also replace the standard "lipid profile" as a target for therapy in at-risk patients.

Restoring E-cadherin expression increases sensitivity to epidermal growth factor receptor inhibitors in lung cancer cell lines

The epidermal growth factor receptor (EGFR) is overexpressed in the majority of non-small cell lung cancers (NSCLC). EGFR tyrosine kinase inhibitors, such as gefitinib and erlotinib, produce 9% to 27% response rates in NSCLC patients. E-Cadherin, a calcium-dependent adhesion molecule, plays an important role in NSCLC prognosis and progression, and interacts with EGFR. The zinc finger transcriptional repressor, ZEB1, inhibits E-cadherin expression by recruiting histone deacetylases (HDAC). We identified a significant correlation between sensitivity to gefitinib and expression of E-cadherin, and ZEB1, suggesting their predictive value for responsiveness to EGFR-tyrosine kinase inhibitors. E-Cadherin transfection into a gefitinib-resistant line increased its sensitivity to gefitinib. Pretreating resistant cell lines with the HDAC inhibitor, MS-275, induced E-cadherin along with EGFR and led to a growth-inhibitory and apoptotic effect of gefitinib similar to that in gefitinib-sensitive NSCLC cell lines including those harboring EGFR mutations. Thus, combined HDAC inhibitor and gefitinib treatment represents a novel pharmacologic strategy for overcoming resistance to EGFR inhibitors in patients with lung cancer.

An alternative technique for totally implantable central venous access devices. A retrospective study of 1311 cases

AIM

The aim of the present study was to report our experience of totally implantable central venous access devices (TICVAD) implantation using two techniques and attempt to define the better technique.

MATERIALS AND METHODS

From January 1998 to September 2003, 1131 patients were reviewed and divided into two groups with implantation by cephalic vein cut-down (group A) done by general surgeons and subclavian vein puncture with the Seldinger technique (group B) done by vascular surgeons. The operative time, early and late complications of these two groups were compared. Data were analysed by Student's t-test.

RESULTS

The average of operative time was 43 min in group A (35-70 min) and 40 min in group B (35-60 min) (P>0.05). No post-operative pneumothorax, hemothorax and fragmentation occurred in group A; the incidence of peri-operative complication was higher in group B. The overall and early complications of group A were significantly lower than that of group B (P<0.0001).

CONCLUSION

This retrospective study showed that the cephalic vein cut-down approach for TICVAD placement avoided the risks of pneumothorax, hemothorax and catheter fragmentation.

Oxidized LDL and small LDL particle size are independently predictive of a selective defect in microcirculatory endothelial function in type 2 diabetes

AIM

To explore the associations of LDL (low-density lipoprotein) particle size and oxidized LDL with endothelium-dependent function of the forearm microcirculation in diabetes.

METHODS

Endothelium-dependent function was examined in 43 middle-aged men and women with type 2 diabetes and 10 age-matched controls. All received aspirin to inhibit endothelial cyclo-oxygenase. Forearm blood flow (FBF) was measured using venous occlusion plethysmography with separate administration of acetylcholine (ACh) and bradykinin (BK) into the brachial artery. Endothelium-independent function was assessed using sodium nitroprusside (SNP). N(G)-monomethyl-L-arginine (L-NMMA) was co-infused with ACh (ACh + L-NMMA) and BK (BK + L-NMMA) to assess non-NO-mediated contributions to endothelium-dependent function.

RESULTS

Subjects with diabetes had impaired endothelium-dependent and endothelium-independent function compared with controls (p < 0.01 for ACh, BK and SNP). In multivariate regression analysis, LDL size (r = 0.41 and p = 0.007), oxidized LDL (r = -0.41 and p = 0.007) and duration of diabetes (r = -0.37 and p = 0.02) predicted FBF response to ACh independently of age, gender and systolic blood pressure. There were no associations between LDL size, oxidized LDL, duration of diabetes and FBF response to BK, SNP, ACh + L-NMMA or BK + L-NMMA.

CONCLUSION

In type 2 diabetes, small dense LDL particles, duration of diabetes and oxidized LDL may independently contribute to endothelial dysfunction of the microcirculation. These disturbances may occur via a selective defect, because ACh and BK activate endothelial NO synthase via different G-protein signal transduction pathways.

Pim Family Kinases Enhance Tumor Growth of Prostate Cancer Cells

Recent analyses indicate that the expression of the Pim-1 protein kinase is elevated in biopsies of prostate tumors. To identify the mechanism by which the Pim kinases may affect the growth of prostate tumors, we expressed Pim-1, Pim-2, or a kinase-dead Pim-2 protein in human PC3 prostate cancer cells. On implantation of the transfectants in nude mice, the growth of the cells expressing Pim-1 or Pim-2 was significantly faster than the growth of the control cells transfected with the neomycin-resistant gene or the kinase-dead Pim-2 protein. When grown in medium, the doubling time of the Pim-1 and Pim-2 transfectants was faster (0.75 days) than that of the control cells (1.28 days). We, therefore, examined the ability of Pim to control the phosphorylation of proteins that regulate protein synthesis. On growth factor starvation or rapamycin treatment, the Pim-1 and Pim-2 transfectants maintained their ability to phosphorylate 4E-BP1 and S6 kinase, although this phosphorylation did not occur in the control-transfected PC3 cells. We have found that the cellular levels of c-Myc were elevated in the Pim-1 and Pim-2 transfectants under these conditions. The Pim-1 and Pim-2 transfectants have lower levels of serine/threonine protein phosphatase 2A (PP2A) activity and the alpha- and beta-subunit B56gamma of the PP2A phosphatase do not coimmunoprecipitate in these cells. Thus, the effects of Pim on PP2A activity may mediate the levels of c-Myc and the phosphorylation of proteins needed for increased protein synthesis. Both of these changes could have a significant impact on tumor growth.

Combination cancer chemotherapy with one compound: pluripotent bradykinin antagonists

Lung and prostate cancers are major health problems worldwide. Treatments with standard chemotherapy agents are relatively ineffective. Combination chemotherapy gives better treatment than a single agent because the drugs can inhibit the cancer in different pathways, but new therapeutic agents are needed for the treatment of both tumor types. Bradykinin (BK) antagonists offer advantages of combination therapy in one compound. These promising multitargeted anti-cancer compounds selectively stimulate apoptosis in cancers and also inhibit both angiogenesis and matrix metalloprotease (MMP) action in treated lung and prostate tumors in nude mice. The highly potent, metabolism-resistant bradykinin antagonist peptide dimer, B-9870 [SUIM-(DArg-Arg-Pro-Hyp-Gly-Igl-Ser-DIgl-Oic-Arg)2] (SUIM=suberimidyl; Hyp=4-hydroxyproline; Igl=alpha-(2-indanyl)glycine; Oic=octahydroindole-2-carboxylic acid) and its non-peptide mimetic, BKM-570 [2,3,4,5,6-pentafluorocinnamoyl-(o-2,6-dichlorobenzyl)-L-tyrosine-N-(4-amino-2,2,6,6-tetramethylpiperidyl)amide] are superior to the widely used but toxic chemotherapeutic drugs cisplatin and taxotere. In certain combinations, they act synergistically with standard anti-cancer drugs. Due to its structure and biological activity, BKM-570 is an attractive lead compound for derivatization and evaluation for lung and prostate cancer drugs.

Association of adiponectin and resistin with adipose tissue compartments, insulin resistance and dyslipidaemia

AIM

In this study, we investigated the association of plasma adiponectin and resistin concentrations with adipose tissue compartments in 41 free-living men with a wide range of body mass index (22-35 kg/m(2)).

METHODS

Using enzyme immunoassays, plasma adiponectin and resistin were measured. Intraperitoneal, retroperitoneal, subcutaneous abdominal and posterior subcutaneous abdominal adipose tissue masses (IPATM, RPATM, SAATM and PSAATM, respectively) were determined using magnetic resonance imaging. Total adipose tissue mass (TATM) was measured using bioelectrical impedance. Insulin resistance was estimated with the help of homeostasis model assessment (HOMA) score.

RESULTS

In univariate regression, plasma adiponectin levels were inversely related to IPATM (r = -0.389, p < 0.05), SAATM (r = -0.500, p < 0.001), PSAATM (r = -0.502, p < 0.001), anterior SAATM (r = -0.422, p < 0.01) and TATM (r = -0.421, p < 0.01). In multiple regression models, adiponectin was chiefly correlated with PSAATM. Plasma adiponectin concentrations were also inversely correlated with HOMA score (r = -0.540, p < 0.001) and triglyceride (r = -0.632, p < 0.001), and positively correlated with high-density lipoprotein cholesterol (r = 0.508, p < 0.001). There were no significant correlations between resistin levels and adipose tissue masses, insulin resistance or dyslipidaemia.

CONCLUSIONS

In men, total body fat is significantly correlated with plasma adiponectin, but not with plasma resistin levels. Low plasma adiponectin levels appear to be chiefly determined by the accumulation of posterior subcutaneous abdominal fat mass, as opposed to intra-abdominal fat, and are strongly predictive of insulin resistance and dyslipidaemia.

Statin therapy improves brachial artery vasodilator function in patients with Type 1 diabetes and microalbuminuria

AIMS

Type 1 diabetes mellitus patients with microalbuminuria have endothelial dysfunction associated with the degree of albuminuria but not with LDL-cholesterol levels. Lipid-lowering agents such as statins may still be of benefit as they can correct endothelial dysfunction by both lipid and non-lipid mechanisms. We therefore examined the effects of atorvastatin on brachial artery endothelial dysfunction in these patients.

METHODS

In a double-blind, randomized crossover study, 16 Type 1 diabetes mellitus patients with microalbuminuria received 6 weeks of atorvastatin 40 mg/day or placebo, separated by a 4-week washout. Brachial artery, endothelium-dependent, flow-mediated dilatation (FMD) and endothelium-independent, glyceryl trinitrate-mediated dilatation (GTNMD) were measured.

RESULTS

Compared with placebo, atorvastatin produced a significant decrease in apolipoprotein B (34.2%), LDL-cholesterol (44.1%) (all P < 0.001), and oxidized-LDL (35.7%, P = 0.03). There was a non-significant increase in plasma cGMP (P = 0.13) on atorvastatin. FMD and GTNMD increased significantly on atorvastatin (FMD: atorvastatin +1.8 +/- 0.4%; placebo +0.2 +/- 0.4%, P = 0.007); (GTNMD: atorvastatin +1.3 +/- 0.9%; placebo -1.2 +/- 0.6%, P = 0.04). An increase in cGMP was independently correlated with an increase in FMD on atorvastatin (adjusted (R2) 0.41, P = 0.02).

CONCLUSION

Atorvastatin improves endothelium-dependent and independent vasodilator function of the brachial artery in Type 1 diabetes mellitus patients with microalbuminuria. This may relate to pleiotropic effects of statins, in particular reduced oxidative stress and increased availability of nitric oxide.