Toward Elimination of Electrochemical Corrosion in Dental Implants: A Zirconia-Titanium Composite Prototype

Background Titanium dental implants (e.g., Nobel Biocare, Switzerland) are routinely used as support for dental restoration. Titanium has been the material of choice due to its corrosion resistance and ability to integrate with bone. Nevertheless, corrosion and titanium dissolution do occur. Compared to control, peri-implantitis tissue biopsies have been shown to contain high concentrations of dissolved titanium as well as metal particles. Dissolved titanium species have been found to be associated with the structure/diversity of the subgingival plaque microbiome and the extent of global methylation. Of note, peri-implantitis and peri-implant mucositis are common biological complications of implant therapy. Microorganisms and local inflammation together with a gradient of oxygen have been proven to form an electrochemical fuel cell, which generates the current that flows through the body of the titanium implant. Effectively, the fuel cell reduces oxygen and oxidizes titanium that turns into a soluble form. We are proposing a new zirconia-titanium composite implant design whereby the electrical current is disrupted while other properties are still conducive to osseointegration. Methodology Biocompatible zirconia bolts were treated with hydrofluoric acid (HF) and coated with titanium in a vacuum evaporator. The coating was masked with nail polish, and unmasked areas were etched with HF followed by mask removal with a solvent. Microbial challenges were conducted with a volunteer's plaque. Regular implant (control) and the prototype were inserted into simulated peri-implant environments implemented as a fiberglass sleeve immersed into a growth medium. After a five-day growth, samples were taken and HNO3 digested. Dissolved titanium was evaluated by inductively coupled plasma mass spectrometry. Results Proof-of-concept implant prototypes were successfully created. Vacuum deposition results in reproducible stable titanium coating. The thickness of the titanium coating was estimated using atomic force microscopy. A microbial challenge revealed that compared to the commercial titanium implant, the new implant prototype showed decreased amounts of corrosion-leached titanium. Conclusions We demonstrate a path forward toward a new design of a dental implant, whereby corrosion-induced electrical currents are interrupted resulting in a decreased amount of dissolved titanium.

PCSK9 inhibition with alirocumab decreases plasma lipoprotein(a) concentration by a dual kinetic mechanism of action

Background

Lipoprotein(a) [Lp(a)] is a low-density lipoprotein (LDL)-like particle, covalently bound to apolipoprotein(a) [apo(a)]. Recent trials show that proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, such as alirocumab, decrease plasma Lp(a) levels and risk of atherosclerotic cardiovascular disease (ASCVD). The kinetic mechanism for lowering Lp(a) by PCSK9 inhibitors may differ according to pre-treatment apo(a) levels.

Purpose

We investigated the effect of alirocumab on Lp(a) metabolism in 21 long-term statin-treated patients [Lp(a) >0.5 g/L in all] with moderate-high (n=10) and high (n=11) apo(a) concentrations according to a cutoff of median apo(a) levels of 145 nmol/L.

Methods

Apo(a) kinetics were studied before and after 12-week treatment with alirocumab (150 mg subcutaneously fortnightly). Apo(a) fractional catabolic rate (FCR) and production rate (PR) were determined using intravenous D3-leucine administration, mass spectrometry and compartmental modelling.

Results

The plasma concentration and PR of apo(a) were significantly higher in patients with high apo(a) than in patients with moderate-high apo(a) levels (273±30 nmol/L vs 130±4.7 nmol/L and 6.0±0.69 nmol/kg/day vs 2.6±0.15 nmol/kg/day, respectively; P<0.001). The FCR of apo(a) was not significantly different between two groups (0.48±0.02 pools/day vs 0.45±0.01 pools/day, P>0.05). In patients with moderate-high apo(a) levels, alirocumab significantly lowered plasma apo(a) levels (−17%, P<0.01) and increased the FCR of apo(a) (+26%, P<0.001), but did not alter apo(a) PR. In contrast, alirocumab significantly lowered plasma apo(a) concentrations (−31%, P<0.001) via a dual mechanism that increased apo(a) FCR (+31%, P<0.001) and lowered PR (−9%, P<0.05) in patients with high apo(a) levels. The reductions in apo(a) concentration and PR with alirocumab in the high apo(a) group remained significant after adjusting for background statin when compared with patients with moderate-high apo(a) levels (P<0.05).

Conclusions

In statin-treated patients with elevated Lp(a), alirocumab may lower elevated plasma Lp(a) concentrations by a dual mechanism of increasing the catabolism and decreasing the production of Lp(a) particles, specifically in patients with relatively high apo(a) concentrations.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This independent research was funded by an Investigator Initiated Study Concept Research Grant from Regeneron Pharmaceuticals and Sanofi (Protocol No. LPS 14508). Figure 1Figure 2

Effect of silver diamine fluoride and potassium iodide on bonding to demineralized dentin

PURPOSE

To evaluate the microtensile bond strength (MTBS) of resin composite to demineralized dentin treated with SDF or SDF-KI.

METHODS

Occlusal enamel of 30 caries-free extracted human molars was removed to expose flat dentin surfaces. Specimens were immersed in demineralizing solution (pH 4.5) for 7 days. A standard smear layer was created using 600-grit silicon carbide paper. Specimens were distributed into three groups (n=10). Control: Dentin rinsed with deionized water; SDF: Dentin treated with 38% SDF; and SDF-KI: Dentin treated with SDF and KI. Specimens were bonded with composite using Scotchbond Universal in etch-and-rinse mode. MTBS beams were prepared from each specimen after 24 hours and tested. Data was analyzed by one-way ANOVA with Tukey HSD post-hoc test.

RESULTS

MTBS test results ranged from 0 to 40 MPa. The highest values were obtained in the Control and lowest in SDF-KI, where pre-test failures were frequently observed. One-way ANOVA showed a significant difference among groups (P< 0.005); post-hoc analysis suggested no statistical difference between Control and SDF, but both groups showed higher MTBS compared with SDF-KI.

CLINICAL SIGNIFICANCE

Silver diamine fluoride can be applied precisely and regionally on demineralized dentin before bonding without compromising the bond strength of a universal adhesive used with phosphoric acid etching. Addition of potassium iodide to reduce discoloration will dramatically weaken the bond.

Blunt Abdominal Trauma with Left Kidney Dropped into Lower Retroperitoneal Cavity: A Case Report and Literature Review

Blunt abdominal injury with kidney laceration is not unusually seen in high-energy traffic accident. It can present with no symptoms and yet lead to fatal complications. High-grade lacerations of kidney (American Association for the Surgery of Trauma [AAST] grade IV to V) will show up with contrast extravasation and disrupted kidney/pelvicalyceal system morphology in computed tomography (CT). However, it is rare to see kidney dislocation from retroperitoneal space because of the presence of the Gerota's fascia. We present a case of a 16-year-old boy suffering from traffic accident with blunt truncal/abdominal injury. The contrast CT of abdomen revealed that his left kidney was dislocated from the original retroperitoneal space and sagged to the lower retroperitoneal cavity. We performed emergency left nephrectomy. He recovered well and there was no complication noted after the surgical intervention. We also review the literature of kidney laceration regarding diagnosis and treatment. (Hong Kong j.emerg.med. 2016;24:176-179)

Nutrition and physical activity in the prevention and treatment of sarcopenia: systematic review

This systematic review summarizes the effect of combined exercise and nutrition intervention on muscle mass and muscle function. A total of 37 RCTs were identified. Results indicate that physical exercise has a positive impact on muscle mass and muscle function in subjects aged 65 years and older. However, any interactive effect of dietary supplementation appears to be limited.

INTRODUCTION

In 2013, Denison et al. conducted a systematic review including 17 randomized controlled trials (RCTs) to explore the effect of combined exercise and nutrition intervention to improve muscle mass, muscle strength, or physical performance in older people. They concluded that further studies were needed to provide evidence upon which public health and clinical recommendations could be based. The purpose of the present work was to update the prior systematic review and include studies published up to October 2015.

METHODS

Using the electronic databases MEDLINE and EMBASE, we identified RCTs which assessed the combined effect of exercise training and nutritional supplementation on muscle strength, muscle mass, or physical performance in subjects aged 60 years and over. Study selection and data extraction were performed by two independent reviewers.

RESULTS

The search strategy identified 21 additional RCTs giving a total of 37 RCTs. Studies were heterogeneous in terms of protocols for physical exercise and dietary supplementation (proteins, essential amino acids, creatine, β-hydroxy-β-methylbuthyrate, vitamin D, multi-nutrients, or other). In 79% of the studies (27/34 RCTs), muscle mass increased with exercise but an additional effect of nutrition was only found in 8 RCTs (23.5%). Muscle strength increased in 82.8% of the studies (29/35 RCTs) following exercise intervention, and dietary supplementation showed additional benefits in only a small number of studies (8/35 RCTS, 22.8%). Finally, the majority of studies showed an increase of physical performance following exercise intervention (26/28 RCTs, 92.8%) but interaction with nutrition supplementation was only found in 14.3% of these studies (4/28 RCTs).

CONCLUSION

Physical exercise has a positive impact on muscle mass and muscle function in healthy subjects aged 60 years and older. The biggest effect of exercise intervention, of any type, has been seen on physical performance (gait speed, chair rising test, balance, SPPB test, etc.). We observed huge variations in regard to the dietary supplementation protocols. Based on the included studies, mainly performed on well-nourished subjects, the interactive effect of dietary supplementation on muscle function appears limited.

Effect of omega-3 fatty acid supplementation on arterial elasticity in patients with familial hypercholesterolaemia on statin therapy

BACKGROUND AND AIMS

Increased arterial stiffness is closely linked with raised blood pressure that contributes substantially to enhanced risk of coronary heart disease in high risk individuals with familial hypercholesterolaemia (FH). Omega-3 fatty acid (ω3-FA) supplementation has been demonstrated to lower blood pressure in subjects with a high cardiovascular disease risk. Whether ω3-FA supplementation improves arterial stiffness in FH subjects, on background statin therapy, has yet to be investigated.

METHOD AND RESULTS

We carried out an 8-week randomized, crossover intervention trial to test the effect of 4 g/d ω3-FA supplementation (46% eicosapentaenoic acid and 38% docosahexaenoic acid) on arterial elasticity in 20 adults with FH on optimal cholesterol-lowering therapy. Large and small artery elasticity were measured by pulse contour analysis of the radial artery. ω3-FA supplementation significantly (P < 0.05 in all) increased large artery elasticity (+9%) and reduced systolic blood pressure (-6%) and diastolic blood pressure (-6%), plasma triglycerides (-20%), apoB concentration (-8%). In contrast, ω3-FAs had no significant effect on small artery elasticity. The change in large artery elasticity was not significantly associated with changes in systolic blood pressure or plasma triglyceride concentration.

CONCLUSIONS

ω3-FA supplementation improves large arterial elasticity and arterial blood pressure independent of statin therapy in adults with FH.

CLINICAL TRIAL REGISTRATION

https://www.clinicaltrials.com/NCT01577056.

AZ1366: An Inhibitor of Tankyrase and the Canonical Wnt Pathway that Limits the Persistence of Non-Small Cell Lung Cancer Cells Following EGFR Inhibition

Purpose: The emergence of EGFR inhibitors such as gefitinib, erlotinib, and osimertinib has provided novel treatment opportunities in EGFR-driven non-small cell lung cancer (NSCLC). However, most patients with EGFR-driven cancers treated with these inhibitors eventually relapse. Recent efforts have identified the canonical Wnt pathway as a mechanism of protection from EGFR inhibition and that inhibiting tankyrase, a key player in this pathway, is a potential therapeutic strategy for the treatment of EGFR-driven tumors.Experimental Design: We performed a preclinical evaluation of tankyrase inhibitor AZ1366 in combination with multiple EGFR-inhibitors across NSCLC lines, characterizing its antitumor activity, impingement on canonical Wnt signaling, and effects on gene expression. We performed pharmacokinetic and pharmacodynamic profiling of AZ1366 in mice and evaluated its therapeutic activity in an orthotopic NSCLC model.Results: In combination with EGFR inhibitors, AZ1366 synergistically suppressed proliferation of multiple NSCLC lines and amplified global transcriptional changes brought about by EGFR inhibition. Its ability to work synergistically with EGFR inhibition coincided with its ability to modulate the canonical Wnt pathway. Pharmacokinetic and pharmacodynamic profiling of AZ1366-treated orthotopic tumors demonstrated clinically relevant serum drug levels and intratumoral target inhibition. Finally, coadministration of an EGFR inhibitor and AZ1366 provided better tumor control and improved survival for Wnt-responsive lung cancers in an orthotopic mouse model.Conclusions: Tankyrase inhibition is a potent route of tumor control in EGFR-dependent NSCLC with confirmed dependence on canonical Wnt signaling. These data strongly support further evaluation of tankyrase inhibition as a cotreatment strategy with EGFR inhibition in an identifiable subset of EGFR-driven NSCLC. Clin Cancer Res; 23(6); 1531-41. ©2016 AACR.

PD-L1 Expression by Two Complementary Diagnostic Assays and mRNA In Situ Hybridization in Small Cell Lung Cancer

INTRODUCTION

Therapeutic antibodies to immune checkpoints show promising results. Programmed death-ligand 1 (PD-L1), an immune checkpoint ligand, blocks the cancer immunity cycle by binding the PD-L1 receptor (programmed death 1). We investigated PD-L1 protein expression and messenger RNA (mRNA) levels in SCLC.

METHODS

PD-L1 protein expression and mRNA levels were determined by immunohistochemistry (IHC) with SP142 and Dako 28-8 PD-L1 antibodies and in situ hybridization in primary tumor tissue microarrays in both tumor cells and tumor-infiltrating immune cells (TIICs) obtained from a limited-disease SCLC cohort of 98 patients. An additional cohort of 96 tumor specimens from patients with extensive-disease SCLC was assessed for PD-L1 protein expression in tumor cells with Dako 28-8 antibody only.

RESULTS

The overall prevalence of PD-L1 protein expression in tumor cells was 16.5%. In the limited-disease cohort, the prevalences of PD-L1 protein expression in tumor cells with SP142 and Dako 28-8 were 14.7% and 19.4% (tumor proportion score cutoff ≥1%) and PD-L1 mRNA ISH expression was positive in 15.5% of tumor samples. Increased PD-L1 protein/mRNA expression was associated with the presence of more TIICs (p < 0.05). The extensive-disease cohort demonstrated a 14.9% positivity of PD-L1 protein expression in tumor cells with Dako 28-8 antibody.

CONCLUSIONS

A subset of SCLCs is characterized by positive PD-L1 and/or mRNA expression in tumor cells. Higher PD-L1 and mRNA expression correlate with more infiltration of TIICs. The prevalence of PD-L1 in SCLC is lower than that published for NSCLC. The predictive role of PD-L1 expression in SCLC treatment remains to be established.

Barasertib (AZD1152), a Small Molecule Aurora B Inhibitor, Inhibits the Growth of SCLC Cell Lines In Vitro and In Vivo

Small-cell lung cancer (SCLC) cells have rapid proliferation, universal Rb inactivation, and high rates of MYC family amplification, making aurora kinase inhibition a natural target. Preclinical studies have demonstrated activity for Aurora A and pan-Aurora inhibitors with some relationship to MYC family expression. A clinical trial showed activity for an Aurora kinase A inhibitor, but no biomarkers were evaluated. We screened a panel of 23 SCLC lines with and without MYC family gene amplification or high MYC family gene expression for growth inhibition by the highly potent, selective aurora kinase B inhibitor barasertib. Nine of the SCLC lines were very sensitive to growth inhibition by barasertib, with IC₅₀ values of <50 nmol/L and >75% growth inhibition at 100 nmol/L. Growth inhibition correlated with cMYC amplification (P = 0.018) and cMYC gene expression (P = 0.026). Sensitive cell lines were also enriched in a published MYC gene signature (P = 0.042). In vivo, barasertib inhibited the growth of xenografts established from an SCLC line that had high cMYC gene expression, no cMYC amplification, and was positive for the core MYC gene signature. Our studies suggest that SCLC tumors with cMYC amplification/high gene expression will frequently respond to Aurora B inhibitors and that clinical studies coupled with predictive biomarkers are indicated. Mol Cancer Ther; 15(10); 2314-22. ©2016 AACR.

Abstract 3047: Sensitization of prostate cancer to chemo-radiation by ribosomal protein S6 inhibition

Radiation Therapy (RT) is curative for most localized prostate cancer (PCA) patients, but is limited by dose-related toxicities and radioresistance. Administration of Nexrutine® (Nx), an inexpensive supplement from Phellodendron amurense bark extract prior to RT inhibited progression to poorly differentiated carcinoma in transgenic adenocarcinoma of the mouse prostate (TRAMP) mice. However, the precise molecular mechanism underlying Nx-mediated tumor growth inhibitory effects in combination with RT is unclear. Using global transcriptome profiling coupled with GeneSpring analysis, we have identified significant modulation of number of signaling pathways including genes involved in mTOR and NFκB signaling. Based on these data, we hypothesized that downregulation of ribosomal protein S6 (rpS6) sensitizes prostate tumor to overcome radioresistance. PCA cell lines had higher levels of total and p-rpS6 compared to non-tumorigenic prostate cell lines. Using clonogenic assays, we observed that pretreatment of Nx for 8h could potentiate the effect of low dose RT in LNCaP (AR positive with WT p53), PC-3 (AR negative & p53 null) and PC-3 AR (AR expressing & p53 null) cells. The combinatorial effect depicted strong synergism and had similar effects as high dose RT. Notably, we observed increased activation of Akt/mTOR/NFκB signaling molecules after treatment of PC-3 cells with RT, which was either abrogated (p-rpS6, p-NFκB & p-p70S6K) or decreased (p-Akt) in cells pretreated with Nx prior to RT. Also, Nx pretreatment inhibited the levels of HIF1-α and CyclinD1, which are downstream targets of rpS6. Using immunofluorescence assay, we saw that the combination treatment increased the γH2AX foci compared to 2 Gy alone, indicating increased DNA damage. This is associated with increased protein levels of key G2/M regulatory proteins including Wee-1, p-cdc2 levels and decreased Chk1, p-cdc25C resulting in prolonged RT-induced G2/M arrest. The combination treatment also caused a significant increase in apoptosis, which was evidenced by increased cleaved PARP levels, subG1 levels and Annexin/PI staining. Strikingly, knockdown of rpS6 sensitized PC-3 cells to RT and reversed the observed effects of Nx, indicating the importance of rpS6 in mediating these changes. Remarkably, p-mTOR, p70S6K, NFκB, Ki67 & Cyclin D1 were decreased in the prostate tissue of mice receiving the combination compared to RT alone. Recently, a phase 0/1 clinical trial of Nx in PCA patients receiving RT decreased PSA levels and was well-tolerated. Interestingly, tumor tissue from Nx treated patients showed decreased rpS6 staining intensity compared to the normal tissue. Collectively, our data suggests that Nx has radiosensitizing effect in a range of PCA cell lines and could prevent progression to advanced PCA by inhibiting rpS6. Supported by NCCAM (R01 AT-007448) & VA-MERIT Award (I01 BX 000766)

Citation Format: Suleman S. Hussain, Carolina B. Livi, Nikos Papanikolaou, Daniel C. Chan, Rita Ghosh, Addanki P. Kumar. Sensitization of prostate cancer to chemo-radiation by ribosomal protein S6 inhibition. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3047.

Effect of niacin on triglyceride-rich lipoprotein apolipoprotein B-48 kinetics in statin-treated patients with type 2 diabetes

AIM

To investigate the effects of extended-release (ER) niacin on apolipoprotein B-48 (apoB-48) kinetics in statin-treated patients with type 2 diabetes (T2DM).

METHODS

A total of 12 men with T2DM were randomized to rosuvastatin or rosuvastatin plus ER niacin for 12 weeks and then crossed to the alternate therapy. Postprandial metabolic studies were performed at the end of each treatment period. D3-leucine tracer was administered as subjects consumed a high-fat liquid meal. ApoB-48 kinetics were determined using stable isotope tracer kinetics with fractional catabolic rates (FCRs) and secretion rates derived using a non-steady-state compartmental model. Area-under-the-curve (AUC) and incremental AUC (iAUC) for plasma triglyceride and apoB-48 were also calculated over the 10-h period after ingestion of the fat meal.

RESULTS

In statin-treated patients with T2DM, apoB-48 concentration was lower with ER niacin (8.24 ± 1.98 vs 5.48 ± 1.14 mg/l, p = 0.03) compared with statin alone. Postprandial triglyceride and apoB-48 AUC were also significantly lower on ER niacin treatment (-15 and -26%, respectively; p < 0.05), without any change to triglyceride and apoB-48 iAUC. ApoB-48 secretion rate in the basal state (3.21 ± 0.34 vs 2.50 ± 0.31 mg/kg/day; p = 0.04) and number of apoB-48-containing particles secreted in response to the fat load (1.35 ± 0.19 vs 0.84 ± 0.12 mg/kg; p = 0.02) were lower on ER niacin. ApoB-48 FCR was not altered with ER niacin (8.78 ± 1.04 vs 9.17 ± 1.26 pools/day; p = 0.79).

CONCLUSIONS

ER niacin reduces apoB-48 concentration by lowering fasting and postprandial apoB-48 secretion rate. This effect may be beneficial for lowering atherogenic postprandial lipoproteins and may provide cardiovascular disease risk benefit in patients with T2DM.

Abstract 1797: Downregulation of ribosomal protein S6 overcomes radioresistance in prostate cancer

Radiation Therapy (RT) is a definitive treatment for early-localized prostate cancer (PCA), but is associated with side effects which impair quality of life in addition to development of radioresistance. PI3K/Akt/mTOR signaling is one of the contributors to therapeutic resistance, including radioresistance. Ribosomal protein S6 (rpS6), a downstream effector of PI3K/Akt/mTOR signaling, mediates radioresistance by increasing protein synthesis, cell survival and epithelial mesenchymal transition. Also, increased activation of rpS6 is correlated with poor survival in PCA. Therefore, downregulation of rpS6 could decrease RT induced toxic side effects by sensitizing tumor cells. Based on published evidence demonstrating tumor growth inhibitory activities, we tested if Nexrutine® (Nx), an inexpensive OTC herbal supplement from Phellodendron amurense bark extract, could potentiate RT by inhibiting rpS6 activation. Using clonogenic assays, low dose RT in combination with Nx was found to have similar inhibition of surviving fraction compared to high dose RT in androgen independent PC-3 cells. Isobologram analysis of these data depicted strong synergism. In addition, increased activation of Akt/NFKB signaling molecules was observed in PC-3 cells exposed to radiation. The observed radiation-induced increase in these signaling molecules was either abolished (p-rpS6, p-NFKB and p-p70S6K) or decreased (p-Akt) in cells pretreated with Nx (8 hours) prior to RT. Additionally, Nx pretreatment prolonged the G2/M arrest caused by RT in PC-3 cells. Strikingly, knockdown of rpS6 in PC-3 cells reversed the observed effects of Nx, indicating the importance of rpS6 in mediating these changes. Furthermore, administration of Nx in combination with RT inhibited prostate tumor progression in transgenic adenocarcinoma of the mouse prostate (TRAMP) mice with no prominent toxicity. Notably, immunohistochemical analysis revealed decreased levels of p-mTOR, p70S6K, NFKB, Ki67 and Cyclin D1 in the prostate in combination group of animals compared to monotherapy. Taken together, our data suggest that Nx sensitizes PCA cells by down regulating rpS6 and delays progression to lethal disease. Remarkably, in a recent phase 0/1 study patients (81%) receiving Nx showed decreased PSA levels with no signs of grade 3 toxicity. Thus, Nx shows immense potential for use as an adjuvant in combination with conventional therapy for effective clinical management of PCA.

Supported by NCCAM (R01 AT-007448) and VA-MERIT Award (I01 BX 000766; APK)

Citation Format: Suleman S. Hussain, Paul Rivas, Roble G. Bedolla, Nikos Papanikolaou, Robert L. Reddick, Brad H. Pollock, Daniel C. Chan, Rita Ghosh, Addanki P. Kumar. Downregulation of ribosomal protein S6 overcomes radioresistance in prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1797. doi:10.1158/1538-7445.AM2015-1797

Abstract 4836: Immune-tolerance due to aberrant expression of Natural Killer-Cell Immunoglobulin-like Receptors (KIRs) on cancer cells and enhanced cancer-platelet interactions

Background: Metastatic cancer cells spread through blood vessels where they constantly interact with platelets and leukocytes, forming tumor microemboli and thereby protected from otherwise rapid elimination from host immune defense cells such as NK cells. We previously demonstrated that metastatic cancer cells with aberrant expression or with forced ectopic expression of Natural Killer Immunoglobulin-like Receptors (KIRs) are more resistant to NK killing than those with null or low KIR expression. Here we report that KIR-expressing cancer cells interact more strongly with platelets leading to significantly increase in NK tolerance than those cancer cells with null or low KIR expression. We have demonstrated that certain anti-platelet antagonists are capable of reversing the NK tolerance of these cancer cells in vitro.

Methods: Aberrant expressions of KIR genes in metastatic cancers derived from orthotopic rat models were detected by DNA microarray analysis and verified with immunohistochemistry and flow cytometry. Stable transformants with ectopic expression of KIR2DL1 or KIR3DL1 were enriched by cell sorting. Binding of cancer cells with human platelets were analyzed by flow cytometry. NK killing of GFP-tagged cancer cells with differential KIR expressions in the presence and absence of human platelets, with or without pretreatment of anti-platelet antagonists or anti-KIR antibodies, was accessed with a fluorescent plate reader.

Results: Using in vitro NK cytotoxic assays, we have found that KIR (aberrant or ectopic) expression or platelet coating on cancers clearly increased their resistance to NK cell killing when compared with parental cells. Interestingly, platelet coating on those metastatic cancer cells with high (aberrant or ectopic) KIR expression increased their IC50 values by 6 to 14 folds respectively when compared with parental cells. We show that NK tolerance correlates positively with platelet coating and the levels of KIR expression on the cancer cells (with correlation coefficient = 0.90 to 0.98), and that the NK resistance is significantly increased when both KIR aberrant expression and platelet coating are present on the cancer cells. However, pretreatment with anti-KIR antibodies and anti-platelet antagonists effectively reverse NK resistance.

Conclusion: Aberrant KIR expression on cancer cells enhances their interaction with platelets leading to significant increase in NK tolerance. Anti-platelet antagonists and anti-KIR antibodies alone or in combination may have clinical potential for the treatment or prevention of metastatic and immune resistant cancer cells.

Citation Format: Daniel CF Chan, Zhiyong Zhang, Di Zheng, Tiffany Chan, Mary Berg, Kathryn Horwitz, Natalie Ahn, Lewis Lanier, Paul Bunn. Immune-tolerance due to aberrant expression of Natural Killer-Cell Immunoglobulin-like Receptors (KIRs) on cancer cells and enhanced cancer-platelet interactions. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4836. doi:10.1158/1538-7445.AM2014-4836

Association between skeletal muscle fat content and very-low-density lipoprotein-apolipoprotein B-100 transport in obesity: effect of weight loss

AIMS

Ectopic deposition of fat in skeletal muscle is a feature of metabolic syndrome, but its specific association with very-low-density lipoprotein (VLDL)-apolipoprotein (apo) B-100 metabolism remains unclear.

METHODS

We examined the association between skeletal muscle fat content and VLDL-apoB-100 kinetics in 25 obese subjects, and the responses of these variables to weight loss. The fat contents of liver, abdomen and skeletal muscle were determined by magnetic resonance imaging, and VLDL-apoB-100 kinetics were assessed using stable isotope tracers.

RESULTS

In obese subjects who were insulin sensitive (homeostasis model assessment, HOMA, score ≤ 2.6, n = 12), skeletal muscle fat content was significantly associated with hepatic fat content (r = 0.636), energy intake (r = 0.694), plasma triglyceride (r = 0.644), apoB-100 (r = 0.529), glucose (r = 0.622), VLDL-apoB-100 concentrations (r = 0.860), VLDL-apoB-100 fractional catabolic rate (FCR; r = -0.581) and VLDL-apoB-100 secretion rate (r = 0.607). These associations were not found in obese subjects who were insulin resistant (HOMA score >2.6, n = 13). Of these 25 subjects, 10 obese subjects underwent a 16-week weight loss program. The low-fat diet achieved significant reduction (p < 0.05) in body weight, visceral and subcutaneous fat areas, liver and skeletal muscle fat, energy intake, triglyceride, insulin, HOMA score, VLDL-apoB100 concentrations and VLDL-apoB100 secretion rate. The percentage reduction of skeletal muscle fat with weight loss was significantly associated with the corresponding changes in VLDL-apoB100 concentration (r = 0.770, p = 0.009) and VLDL-apoB-100 secretion (r = 0.682, p = 0.030).

CONCLUSIONS

Skeletal muscle fat content is associated with VLDL-apoB-100 transport. Weight loss lowers skeletal muscle fat and VLDL-apoB-100 secretion.

Abstract 4626: Evaluating the pharmacodynamics and pharmacokinetic effects of MM-398, a nanoliposomal irinotecan (nal-IRI) in subcutaneous xenograft tumor models of human squamous cell carcinoma and small cell lung cancers

Background: MM-398 is a novel nanoliposomal encapsulation of irinotecan (nal-IRI), a topoisomerase I inhibitor. In preclinical studies, nal-IRI has been shown to greatly modify the pharmacokinetics and biodistribution of CPT-11 and its active metabolite, SN-38, thereby improving its activity. In this report, we evaluate the in vivo activity of nal-IRI in the two xenograft models of lung cancer. A pharmacodynamics (PD) study was performed to measure the drug activation and deposition parameters in these tumor models. In addition we investigated the effects of nal-IRI on tumor growth, tumor-associated macrophages (TAM's), vasculature, cell proliferation, and apoptosis.

Methods: Xenograft models of subcutaneous H157 squamous cell carcinoma (SCC) and H841 small cell lung cancer (SCLC) were established in mice. A short pharmacodynamics (PD) study was performed, wherein, 24 hours after a single dose, animals were euthanized and tumors collected. PD analysis included profiling for carboxylesterase (CES) levels, vasculature (CD31), macrophage (F4/80), and metabolite (CPT-11 and SN-38) levels. For the tumor activity study, animals (5 per group) were treated by weekly i.v. injections with placebo liposome, free irinotecan at 25 mg/kg/wk, or nal-IRI at 30 and 50 mg/kg/wk for three weeks. Tumor volumes were measured with digital calipers. IHC analysis was performed for TAM content, tumor proliferation (Ki67), apoptosis, and vasculature.

Results: (1) The carboxylesterase enzyme (activation) and CPT-11 (deposition) tumor levels resulted in extended intratumor SN38 duration, as predicted by the model simulation; (2) nal-IRI suppressed H157 tumor growth in a dose dependent manner, much more efficiently than free irinotecan. On day 25, nal-IRI, at 30 and 50 mg/kg/wk, inhibited tumor growth by 92.6% and 96.3%, respectively, when compared with placebo liposome. In contrast, free irinotecan inhibited tumor growth by 55.7%; (3) For the SCLC H841 xenograft, on day 35, nal-IRI at 30 and 50 mg/kg/wk, also inhibited tumor growth by 84.9% and 93.4% respectively, greater than free irinotecan by 32.7%, when compared with placebo liposome. No obvious toxicities or weight loss were noted in the nal-IRI treated groups; (4) TAM levels were significantly (p&lt;0.05) higher in tumors treated with nal-IRI (30mg/kg and 50mg/kg), as compared to control or free irinotecan treated tumors.

Conclusion: nal-IRI inhibited tumor growth in lung tumor xenograft models, suggesting the treatment of human SCC and SCLC, in which there are high unmet medical needs, as a potential target for clinical investigation.

Citation Format: Daniel CF Chan, Ashish Kalra, Zhiyong Zhang, Nancy Paz, Dmitri Kirpotin, Daryl Drummond, Ulrik Nielsen, Paul A. Bunn, Jonathan Fitzgerald. Evaluating the pharmacodynamics and pharmacokinetic effects of MM-398, a nanoliposomal irinotecan (nal-IRI) in subcutaneous xenograft tumor models of human squamous cell carcinoma and small cell lung cancers. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4626. doi:10.1158/1538-7445.AM2014-4626

Atorvastatin plus omega-3 fatty acid ethyl ester decreases very-low-density lipoprotein triglyceride production in insulin resistant obese men

AIM

To test the effect of atorvastatin (ATV) and ATV plus ω-3 FAEEs on VLDL-TG metabolism in obese, insulin resistant men.

METHODS

We carried out a 6-week randomized, placebo-controlled study to examine the effect of ATV (40 mg/day) and ATV plus ω-3 FAEEs (4 g/day) on VLDL-TG metabolism in 36 insulin resistant obese men. VLDL-TG kinetics were determined using d5 -glycerol, gas chromatography-mass spectrometry and compartmental modelling.

RESULTS

Compared with the placebo, ATV significantly decreased VLDL-TG concentration (-40%, p < 0.001) by increasing VLDL-TG fractional catabolic rate (FCR) (+47%, p < 0.01). ATV plus ω-3 FAEEs lowered VLDL-TG concentration to a greater degree compared with placebo (-46%, p < 0.001) or ATV monotherapy (-13%, p = 0.04). This was achieved by a reduction in VLDL-TG production rate (PR) compared with placebo (-32%, p = 0.008) or ATV (-20%, p = 0.03) as well as a reciprocal increase in VLDL-TG FCR (+42%, p < 0.05) compared with placebo.

CONCLUSION

In insulin resistant, dyslipidaemic, obese men, ATV improves VLDL-TG metabolism by increasing VLDL-TG FCR. The addition of 4 g/day ω-3 FAEE to statin therapy provides further TG-lowering by lowering VLDL-TG PR.

Tankyrase and the canonical Wnt pathway protect lung cancer cells from EGFR inhibition

Lung cancer is the leading cause of death worldwide. Adenocarcinomas, the most common histologic subtype of non-small cell lung cancer (NSCLC), are frequently associated with activating mutations in the epidermal growth factor receptor (EGFR) gene. Although these patients often respond clinically to the EGFR tyrosine kinase inhibitors erlotinib and gefitinib, relapse inevitably occurs, suggesting the development of escape mechanisms that promote cell survival. Using a loss-of-function, whole genome short hairpin RNA (shRNA) screen, we identified that the canonical Wnt pathway contributes to the maintenance of NSCLC cells during EGFR inhibition, particularly the poly-ADP-ribosylating enzymes tankyrase 1 and 2 that positively regulate canonical Wnt signaling. Inhibition of tankyrase and various other components of the Wnt pathway with shRNAs or small molecules significantly increased the efficacy of EGFR inhibitors both in vitro and in vivo. Our findings therefore reveal a critical role for tankyrase and the canonical Wnt pathway in maintaining lung cancer cells during EGFR inhibition. Targeting the Wnt-tankyrase-β-catenin pathway together with EGFR inhibition may improve clinical outcome in patients with NSCLC.

Abstract 1941: Development of novel NSAID conjugated molecules for lung cancer therapy

Background: Many promising chemopreventive Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) such as Flurbiprofen have acquired anti-cyclooxygenase 2 (COX2) effects with anti-cancer activities. Recently several phosphorylated-NSAID compounds were shown to improve the therapeutic potency over the parental NSAID molecules (JPET 111.183533, 2011) by 10 to 30 folds. Previously, we also reported several novel and potent molecules by the incorporation of NSAIDs such as aspirin, indomethancin, ketorolac, ketoprofen, and sulindac into the aclyting N-terminal of our lead mimetic molecules B317 (F5C-OC2Y-Atmp) (AACR 45: 476, 2004). Here we report a new series of highly potent molecules by replacing the N-terminal F5C with a flurbiprofen (Fbp). The resultant molecules effectively inhibit many cancer cell lines in vitro and in vivo, with efficacy much better than the unmodified parental NSAID molecules or those phosphorylated NSAID analogs. Methods: Standard MTT assays were used to access growth inhibitory effects of the parental and NSAID conjugated molecules. Effects of drugs on cell cycle and apoptosis were analyzed by flow cytometry. In vivo efficacy was evaluated in subcutaneous lung xenografts in athymic nude mice. Results: 32 lung cancer cell lines including 24 NSCLC and 8 SCLC cell lines were treated with various concentrations of some selected conjugated drugs for 4 days. The best compound had an average IC 50 value of 0.5 uM, with a range of 0.1 to 2 uM, while parental Flurbiprofen had IC50 value of 500 uM, with a range of 200 uM to 800uM. Cell cycle analysis showed that exposure of lung cancer cells to these new conjugates resulted in a significant shift of cells from S and G2 phases into G1 arrest, resulting in high percentage of apoptotic cell deaths in a dose- and time-dependent manner. Finally, our in vivo efficacy studies demonstrated that new NSAID conjugates at 5 mg/kg by daily ip injections significantly suppressed growth of subcutaneous xenografts of human lung adenocarcinoma in athymic nude mice without causing weight loss. Conclusion: Our new NSAID conjugate is a novel class of therapeutic agent with anti-growth effects against lung cancer cells in vitro and in vivo, with a 1000 fold increase in potency than the parental Flurbiprofen.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1941. doi:1538-7445.AM2012-1941

A translation inhibitor identified in a Drosophila screen enhances the effect of ionizing radiation and taxol in mammalian models of cancer

We described previously a screening protocol in Drosophila melanogaster that allows us to identify small molecules that increase the killing effect of ionizing radiation in vivo in a multicellular context. The ability of this screen to identify agents that enhance the effect of radiation in human cancer models has been validated in published proof-of-concept studies. Here we describe an agent, identified by screening through two National Cancer Institute (NCI) small molecule libraries in Drosophila, that increases the effect of radiation. This agent, Bouvardin (NSC 259968), inhibits the elongation step of protein synthesis. We find that Bouvardin enhances the killing effect of X-rays in both Drosophila larvae and in human cancer cells. More detailed analysis showed that Bouvardin also increases the effect of radiation in clonogenic assays and in human cancer xenografts in mice. Finally, we present data that Bouvardin can also increase the efficacy of taxol. Regulation of translation is important to cancer biology. Current therapies target every aspect of cancer cell proliferation from growth factor signaling to cell division, with the exception of translation elongation. Our identification of Bouvardin as an enhancer of radio- and chemo-therapeutic agents suggests that targeting this niche has the potential to improve existing cancer therapies.

The relationship between acid-suppressing drugs and phytobezoar formation: a retrospective analysis and discussion of phytobezoar formation

OBJECTIVES

Although phytobezoars are a rare cause of gastrointestinal obstruction, they are most commonly found in patients with previous gastric surgery. It is well known that predisposing factors of phytobezoar formation are ingestion of fruits containing soluble tannin, presence of dilute hydrochloric acid in the stomach, and gastric stasis or delayed emptying. We investigated whether intake of acid-suppressing drugs that neutralize gastric acidity or inhibit gastric acid secretion to constitute a hypo-acidic condition, increases the risk of phytobezoar formation.

MATERIALS AND METHODS

Between September 1992 and October 2008, 32 patients (24 male and 8 female) with gastrointestinal phytobezoars were diagnosed either surgically or endoscopically at the Tri-Service General Hospital, Taipei, Republic of China. The data were collected from hospital records and analyzed retrospectively.

RESULTS

Eighteen (56.25%) of all patients had previous gastric surgery and 6 (42.9%) of the 14 patients who had not undergone surgery had diabetes mellitus. The majority of admissions were during winter and spring (between October and March) (P < 0.01) and none of the patients had taken acid-suppressing drugs during the 6 months before detection of gastrointestinal phytobezoars.

CONCLUSIONS

In our study, intake of acid-suppressing drugs did not increase the risk of phytobezoar formation in patients with normal gastric motility. Moreover, we believe that the major factor in phytobezoar formation is gastric stasis or delayed emptying, which sufficiently prolongs the retention period of materials in the stomach, while dilute hydrochloric acid is a minor factor.

The effect of fenofibrate on HDL cholesterol and HDL particle concentration in postmenopausal women on tibolone therapy

BACKGROUND

Low high-density lipoprotein (HDL) cholesterol and particle concentration are risk factors for coronary heart disease in women. Tibolone lowers HDL cholesterol and HDL particle concentration, an effect that could be reversed by the peroxisome proliferator-activator receptor-α agonist fenofibrate.

OBJECTIVE

To assess the effects of fenofibrate on plasma HDL particles in postmenopausal women taking tibolone therapy.

DESIGN AND PARTICIPANTS

Randomized crossover study conducted in a women's health clinic. Fourteen postmenopausal women taking tibolone 2.5 mg daily for menopausal symptoms were randomized to either fenofibrate 160 mg daily or no treatment for 8 weeks, followed by a 3-week wash-out for fenofibrate and then crossed over to alternate therapy for another 8 weeks. The main outcome measure was changes in plasma HDL cholesterol concentration, apoA-I and apoA-II, LpA-I and LpA-I-A-II.

RESULTS

After 8 weeks of fenofibrate therapy, there was no change in HDL cholesterol, 1.13 ± 0.06 v 1.16 ± 0.06 mmol/l (P = 0.47) or apoA-I, 1.19 ± 0.05 v 1.20 ± 0.05 g/l (P = 0.23). LpA-I fell significantly 0.35 ± 0.03 v 0.29 ± 0.02 (P = 0.02) but there was a rise in apoA-II, 0.35 ± 0.01 v 0.39 ± 0.01 g/l (P = 0.01). There was a significant fall in total cholesterol, triglycerides, low-density lipoprotein cholesterol and apoB.

CONCLUSION

In women taking tibolone, fenofibrate increases plasma apoA-II concentration and effects a redistribution of HDL subfractions but does not correct tibolone-induced changes in HDL cholesterol or HDL particle concentration. The mechanism and significance of this require further investigation.

Fenofibrate concomitantly decreases serum proprotein convertase subtilisin/kexin type 9 and very-low-density lipoprotein particle concentrations in statin-treated type 2 diabetic patients

AIM

Diabetic dyslipidaemia, characterized by hypertriglyceridaemia as a result of elevated serum very-low-density lipoprotein (VLDL) concentrations, contributes to the increased risk of cardiovascular disease (CVD) in type 2 diabetes (T2DM). Proprotein convertase subtilisin/kexin type 9 (PCSK9) may play a role in regulating VLDL metabolism. We investigated the effect of fenofibrate on serum PCSK9 and VLDL particle concentrations in T2DM patients already receiving statin therapy.

METHODS

In a double-blind randomized crossover study, 15 statin-treated T2DM patients (63 +/- 8 years, body mass index (BMI) 29 +/- 3 kg/m(2)) were treated with fenofibrate (145 mg/day) or matching placebo for 12 weeks. Serum PCSK9 concentrations were measured by immunoassay. VLDL particle concentration and size were determined by nuclear magnetic resonance spectroscopy.

RESULTS

Fenofibrate decreased serum triglycerides (-23%), VLDL-triglycerides (-51%), total cholesterol (-11%), LDL-cholesterol (-16%), apolipoprotein B-100 (-16%), apolipoprotein C-III (-20%) and PCSK9 (-13%) concentrations compared with placebo (p < 0.05). Fenofibrate also decreased serum concentrations of large (-45%), medium (-66%) and small VLDL (-67%) particles (p < 0.05), without altering VLDL particle size. Serum PCSK9 reduction correlated with decreases in total (r = 0.526, p = 0.044) and small (r = 0.629, p = 0.021) VLDL particle concentrations.

CONCLUSIONS

Fenofibrate concomitantly decreased serum PCSK9 and VLDL particle concentrations in statin-treated T2DM patients. These findings support a mechanistic link between PCSK9 and VLDL metabolism, possibly through an effect of PSK9 on VLDL receptor degradation.

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.

The Effects of Cetuximab Alone and in Combination With Radiation and/or Chemotherapy in Lung Cancer

Purpose: The epidermal growth factor receptor (EGFR) overexpressed in approximately 80% of non-small cell lung cancers (NSCLC) is a target for novel therapeutics. Concurrent chemoradiation is the current standard of care for treatment of patients with locally advanced NSCLC. However, &lt; 20% of patients remain disease-free at 5 years despite this aggressive treatment. Cetuximab is a humanized monoclonal antibody that recognizes the human EGFR, and in previous studies, inhibited the growth of EGFR-expressing human cancer cell lines. In this report, we investigated the cellular and molecular effects of cetuximab alone and in combination with radiation and/or chemotherapy in human NSCLC cell lines with varying levels of EGFR overexpression in vitro and in vivo.

Experimental Design: We evaluated the EGFR status of a panel of human NSCLC cancer cell lines by immunohistochemistry and flow cytometry. We then evaluated cetuximab effects on growth, cell cycle distribution, and downstream intracellular signaling molecules in this panel of NSCLC cancer cell lines. NSCLC cell lines were treated with cetuximab alone or in combination with radiation, chemotherapy, or chemoradiation to determine the cooperative effects of cetuximab both in vitro and in vivo in athymic nude mice bearing NSCLC xenografts.

Results: Cetuximab alone inhibited the in vitro growth of some but not all EGFR-expressing NSCLC cell lines in a dose-dependent manner. Flow cytometric analysis of cell cycle distribution after 24 hours of cetuximab treatment revealed a shift into the G0/G1 phase of the cell cycle in cetuximab-sensitive EGFR-expressing cell lines and at concentrations that were growth-inhibitory. There were no cell cycle changes in the EGFR-negative cell lines. After 4 hours of exposure, cetuximab reduced epidermal growth factor (EGF)-induced phosphorylation of EGFR (pEGFR) and HER-2 (pHER2) in cetuximab-sensitive cell lines but not in cetuximab-resistant cell lines. Cetuximab reduced EGF-induced phosphorylation of extracellular signal-regulated kinase-1/2 (pERK) in all EGFR-expressing cell lines. In the absence of EGF, cetuximab alone increased the level of pEGFR and pHER2 above that seen in untreated control cells in both sensitive and resistant cell lines that were EGFR- and HER2-positive, but not in EGFR- or HER2-negative lines. Despite the cetuximab-induced increase in phosphorylation of EGFR and HER2, peak EGF-induced levels of pEGFR and pHER2 were reduced by cetuximab in the cetuximab-sensitive lines but not in the resistant lines. Cooperative (combination index values &lt; 1.0) growth inhibitory effects were observed in vitro combination assays with cetuximab and radiation only in cetuximab-sensitive NSCLC cell lines. A lack of cooperation was seen in cetuximab-insensitive NSCLC cell lines. Similar findings were observed with in vitro combination studies of cetuximab plus cisplatin or paclitaxel. In nude mice bearing EGFR-expressing, cetuximab-sensitive, NSCLC cell line xenografts, cetuximab plus radiation induced a marked improvement in tumor growth inhibition over either agent alone. The growth inhibitory effects of cetuximab-radiation were similar to the growth inhibitory effects of concurrent chemoradiation. Triple combination therapy of cetuximab and chemoradiation yielded a nonsignificant advantage in tumor growth control over doublet combinations (cetuximab and radiation or chemoradiation) in vivo.

Conclusions: Similar results in tumor growth inhibition observed in mice treated with cetuximab-radiation and cisplatin-radiation provide a rationale for the clinical investigation of cetuximab with concurrent radiation in selected patients with locally advanced NSCLC. Local tumor control and treatment toxicity should be evaluated between cetuximab-radiation and chemoradiation regimens. Proper patient selection will be critical to the success of such trials and further studies are needed to identify optimal patient selection criteria.