Evaluating compliance with the care standard of proactively assessing bone health in patients with diabetes: a pilot audit of practice across Asia by the Asia Pacific Consortium on Osteoporosis (APCO)

This pilot audit explored how bone health is assessed patients with diabetes in diverse centres across Asia. Only 343 of 1092 (31%) audited patients had a bone health assessment, 27% of whom were diagnosed with osteoporosis. Quality improvement strategies are needed to address gaps in patient care in this area.

PURPOSE

The Asia Pacific Consortium on Osteoporosis (APCO) Framework outlines clinical standards for assessing and managing osteoporosis. A pilot audit evaluated adherence to clinical standard 4, which states that bone health should be assessed in patients with conditions associated with bone loss and/or increased fracture risk; this report summarises the audit findings in patients with diabetes. A secondary aim was to assess the practicality and real-world use of the APCO bone health audit tool kit.

METHODS

Eight centres across Asia participated in the pilot audit, selecting diabetes as the target group. Participants reviewed their practice records for at least 20 consecutively treated patients with the target condition. Questions covered routine investigations, bone health assessment, osteoporosis diagnosis, and patient referral pathways. Data were summarised descriptively.

RESULTS

The participants represented public hospitals, university medical centres, and private clinics from India, Malaysia, Pakistan, Singapore, Taiwan, and Vietnam that see an estimated total of 95,000 patients with diabetes per year. Overall, only 343 of 1092 audited patients (31%) had a bone health assessment. Osteoporosis was subsequently diagnosed in 92 of 343 (27%) patients.

CONCLUSION

Bone health was not assessed in most patients with diabetes. The results provide insight into current practices across diverse Asian centres and demonstrate the practical value of the audit tool kit. Participant feedback has been used to improve the tool kit. Results of this pilot audit are being used in the respective centres to inform quality improvement projects needed to overcome the gap in patient care.

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.