Abstract PD05-12: Combination of Notch Inhibitor MK-0752 and Endocrine Therapy for Early Stage ERα + Breast Cancer in a Presurgical Window Pilot Study

Background: Breast tumor initiating cells (TIC) use Notch receptors/ligands with other pathways for self renewal, resulting in tumor proliferation and progression. We showed that Notch inhibition with gamma secretase inhibitors (GSI) potentiates the effects of tamoxifen (tam) in xenografts (Rizzo et al. Cancer Res 2008). It is unknown whether GSIs plus endocrine therapy result in modulation of Notch and other proliferation markers in human breast cancer. Our objective was to add short exposure of the GSI MK-0752 to ongoing tam or letrozole (letr) during the presurgical window to determine 1) feasibility, 2) safety/tolerance, and 3) impact on biomarkers. We report the initial cohort of this pilot study (ClinTrials. gov NCT00756717).

Methods: Patients (pts) with early stage ERα + breast cancer were treated with 25 days of tam or letr. On day 15 MK-0752 was added to endocrine therapy (350 mg orally 3 days on, 4 days off, 3 days on), with definitive surgery day 25. Formalin fixed, paraffin embedded biopsies were obtained at baseline, day 14 and final surgery, with histologic confirmation of tumor content >50% and RNA extraction by standard methods. Q-PCR was done for Notch1, Notch3, Notch4, Deltex, Jagged1, c-myc, HEY1, HEY2, HES1, PS2, C-Myc, Cyclin A2, NOXA (pro-apoptotic protein), Ki67, Dicer-1, RPL13 (internal control). Ct averages for 3 replicates were used and mRNA levels were calculated by the 2ΔΔCt method. Baseline gene expression levels were used as comparators for days 14 and 25 levels in each pt. The first cohort of 10 pts was analyzed to determine if enough signals were present to justify expanding the cohort at this dose to 20 pts and possibly test a second cohort on an alternate MK-0752 dose/schedule. Results: The initial cohort of 10 pts completed all therapy (4 tam, 6 letr), all biopsies and definitive surgery on schedule. One other pt withdrew prior to starting MK-0752 due to hypertension. Toxicity was minimal: grade 1 periorbital edema/cough, nausea, and axillary paresthesias in 1 pt each; grade 1 facial rash, 2 pts; and grade 2 fatigue, 1 pt. There was no diarrhea or surgical complications. Significant changes occurred in molecular marker levels after MK-0752 plus tam/letr (day 25) vs. end of tam/letr alone (day 14) as follows: Ki67 mRNA decreased in 9/10 pts; Notch4 decreased, 10/10; NOXA increased, 6/10; and Notch1 decreased, 6/10. Other markers showed inter-individual variations and will be presented, along with results of the global gene expression profiling (in progress). Conclusions: The addition of a short exposure of the GSI MK-0752 to ongoing endocrine therapy was feasible, safe, and well tolerated in pts with ERα + early breast cancer prior to definitive surgery. It results in anti-proliferative and pro-apoptotic effects at the molecular level. Notch4, which plays a key role in breast TIC, was the most consistent molecular marker of response in this setting. This suggests a potential anti-TIC effect of this combination and a role in overcoming endocrine resistance. Accrual to the expanded cohort is underway. If findings are confirmed, the second study with alternate MK-0752 dose/schedule may commence. Funding: Swim Across America, Inc. (clinical trial costs); Merck (drug supply, profiling)

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD05-12.

Prevalence of obesity among affluent school children in Dhaka

A cross sectional study was conducted in September 2006 in one of the private schools in Dhaka, Bangladesh to see the prevalence of obesity among affluent school children and adolescents. Informed consent was taken from school authority to take anthropometric measurement of all school children. Standing height was measured with a stadiometer and weight with a bathroom scale. Waist and hip circumference were measured with a measuring tape. The body mass index (BMI) was calculated using weight in kilogram/(height in meter)2 formula. Obesity was defined as BMI≥95th percentile for age and sex, over weight as BMI≥85th percentile for age and sex, normal weight as BMI between 5th and 84th percentile and underweight as BMI <5th percentile. Official centers for disease control (CDC) growth chart for boys and girls age 2-20 years was used. Children and adolescents were divided into group 1(3-5 years), Group 2(6-9years), group 3(10-13 years) and group 4(14-18 years). There were a total of 468 children and adolescents (male 266, female 202). In group 1 there were 110 children, in group 2 there were177 children, in group 3 and 4 there were 149 and 32 adolescents respectively. The prevalence of obesity was 17.9%, higher among males (19.9%), compared to females (15.3%). Obesity was highest (27.7%) in group 2, 14.5% in group 1, 10.7% in group 3 and 9.4% in group 4.

A Phase II trial of 17-allylamino, 17-demethoxygeldanamycin (17-AAG, tanespimycin) in patients with metastatic melanoma

PURPOSE

A Phase II study to screen for anti-melanoma activity of the heat shock protein 90 (HSP90) inhibitor, 17-AAG (17-allylamino-17-demethoxygeldanamycin) was performed. The primary endpoint was the rate of disease stabilisation in patients with progressive, metastatic melanoma treated with 17-AAG. Secondary endpoints were to determine: the toxicity of 17-AAG, the duration of response(s), median survival and further study the pharmacokinetics and pharmacodynamics of 17-AAG.

PATIENTS AND METHODS

Patients with metastatic melanoma (progressive disease documented ≤6 months of entering study) were treated with weekly, intravenous 17-AAG. A Simon one sample two stage minimax design was used. A stable disease rate of ≥25% at 6 months was considered compatible with 17-AAG having activity.

RESULTS

Fourteen patients (8 male: 6 female) were entered, eleven received 17-AAG (performance status 0 or 1). Median age was 60 (range 29-81) years. The majority (93%) received prior chemotherapy and had stage M1c disease (71%). Toxicity was rarely ≥ Grade 2 in severity and commonly included fatigue, headache and gastrointestinal disturbances. One of eleven patients treated with 17-AAG had stable disease for 6 months and median survival for all patients was 173 days. The study was closed prematurely prior to completion of the first stage of recruitment and limited planned pharmacokinetic and pharmacodynamic analyses.

CONCLUSION

Some evidence of 17-AAG activity was observed although early study termination meant study endpoints were not reached. Stable disease rates can be incorporated into trials screening for anti-melanoma activity and further study of HSP90 inhibitors in melanoma should be considered.

Antioxidant enzymes in brackishwater oyster, Saccostrea cucullata as potential biomarkers of polyaromatic hydrocarbon pollution in Hooghly Estuary (India): seasonality and its consequences

Use of antioxidant enzymes as biomarkers often becomes a complicated process at application level because they show considerable seasonal fluctuation due to both natural and biological factors. In this study, we studied the consequences of seasonal variation of antioxidant enzymes [catalase (EC 1.11.1.6), superoxide dismutase (SOD, EC 1.15.1.1), glutathione peroxidase (GPX, EC 1.11.1.9) and microsomal NADPH-DT diaphorase (EC 1.6.99.2)] in the digestive gland of wild brackishwatcr oysters, Saccostrea cucullata for biomonitoring against polyaromatic hydrocarbon (PAH) contamination in Hooghly Estuary, north-eastern coast of India. As a general trend, maximum antioxidant enzyme activities were detected in pre-monsoon period or summer (March-June) followed by a gradual decrease during monsoon (July-October) with a minimum in post-monsoon period or winter (November-February) and this pattern was similar to tissue concentrations of PAHs also. The physiological fluctuations of the antioxidant defense systems were inversely-related to the lipid peroxidation indicating an enhanced susceptibility of oyster tissues to oxidative stress during post-monsoon or winter period. However, the oysters from polluted populations exhibited consistent very high PAHs load in their tissues as well as significant increases in the activities of antioxidant enzymes than in non-polluted populations in all three seasons. The results indicated that the antioxidant enzymes, catalase, SOD and microsomal NADPH-DT diaphorase in digestive gland of S. cucullata could be useful biomarkers of PAHs contamination. It also emphasized that seasonal variation of potential biomarkers like such enzymes should be incorporated into interpretation of biomonitoring studies by the use of appropriate controls and identical treatment in analysis of polluted and non-polluted samples.

Seasonal variation of antioxidant and biotransformation enzymes in barnacle, Balanus balanoides, and their relation with polyaromatic hydrocarbons

Seasonal variations in the antioxidant enzymes (catalase, superoxide dismutase [SOD], NADH-DT diaphorase), biotransformation enzyme, glutathione-S-transferase (GST) and microsomal lipid peroxidation in digestive tissue of barnacle, Balanus balanoides, from polluted and non-polluted populations have been evaluated. Relationships with accumulated polyaromatic hydrocarbon (PAH) concentration in barnacle tissues and environmental parameters (water temperature, salinity, dissolved oxygen concentration, water pH) were determined. As a general trend, maximum antioxidant enzyme and GST activities were detected in the pre-monsoon period or summer (March-June) followed by a gradual decrease during the monsoon (July October) with a minimum in the post-monsoon period or winter (November February). This pattern was similar to tissue concentrations of PAHs, resulting in a significant positive correlation with antioxidant enzymes, mainly catalase and SOD. Microsomal lipid peroxidation exhibited an almost reverse trend of seasonal variation to that of antioxidant enzyme activities indicating an enhanced susceptibility of barnacle tissues to oxidative stress. Among the environmental parameters, only water temperature seemed to have a significant effect on observed variations of antioxidant enzymes and GST activities. The barnacles from polluted and non-polluted populations exhibited seasonal differences in the activities of all the enzymes studied, particularly catalase, SOD and GST, suggesting the possibility of some biochemical adaptation in organisms from a chronically polluted environment. The results indicated that antioxidant defense components, catalase and SOD, are sensitive parameters that could be useful biomarkers for the evaluation of contaminated aquatic ecosystems. The results also suggested the potentiality of barnacle, B. balanoides, as a bioindicator organism against organic pollution.

Revised translation start site for secM defines an atypical signal peptide that regulates Escherichia coli secA expression

The secretion-responsive regulation of Escherichia coli secA occurs by coupling its translation to the translation and secretion of an upstream regulator, secM (formerly geneX). We revise the translational start site for secM, defining a new signal peptide sequence with an extended amino-terminal region. Mutational studies indicate that certain atypical amino acyl residues within this extended region are critical for proper secA regulation.

Snake venom hemorrhagins

Viperine and crotaline snake venoms contain one or more hemorrhagic principles called hemorrhagins. These are zinc-containing metalloproteases characterized by the presence of a protease domain, with additional domains in some of them. They act essentially by degrading the component proteins of basement membrane underlying capillary endothelial cells. The toxins also act on these cells causing lysis or drifting apart, resulting in hemorrhage per rhexis or per diapedesis. Some of these toxins have been found to exert additional effects such as fibrinogenolysis and platelet aggregation that facilitate hemorrhage. The structural and functional features of this class of toxins have been discussed in this review in an attempt to get a better understanding of their toxicity. This can be of immense therapeutic value in the management of snake venom poisoning, as hemorrhagins are among the major lethal factors in snake venom.

Regulation of Escherichia coli secA by cellular protein secretion proficiency requires an intact gene X signal sequence and an active translocon

secA is translationally regulated by the protein secretion proficiency state of the Escherichia coli cell. This regulation was explored by making signal sequence mutations in the gene upstream of secA, gene X, which promotes secA translational coupling. Gene X signal sequence mutants were constitutive for secA expression, while prlA alleles partially restored secA regulation. These results show that interaction of the pre-gene X protein with the translocon is required for proper secA regulation. Furthermore, gene X signal sequence mutations disrupted secA regulation only in the cis configuration. We propose that nascent pre-gene X protein interacts with the translocon during its secretion to constitute the secretion sensor.

Single dose vitamin A treatment in acute shigellosis in Bangladesh children: randomised double blind controlled trial

OBJECTIVE

To evaluate the efficacy of a single large oral dose of vitamin A in treating acute shigellosis in children in Bangladesh.

DESIGN

Randomised double blind controlled clinical trial.

SETTING

Dhaka Hospital, International Centre for Diarrhoeal Disease Research, Bangladesh.

SUBJECTS

83 children aged 1-7 years with bacteriologically proved shigellosis but no clinical signs of vitamin A deficiency; 42 were randomised to treatment with vitamin A and 41 formed a control group.

INTERVENTION

Children were given a single oral dose of 200,000 IU of vitamin A plus 25 IU vitamin E or a control preparation of 25 IU vitamin E.

MAIN OUTCOME MEASURES

Clinical cure on study day 5 and bacteriological cure.

RESULTS

Baseline characteristics of the subjects in the two treatment groups were similar. Significantly more children in the vitamin A group than in the control group achieved clinical cure (19/42 (45%) v 8/14 (20%); chi 2 = 5.14, 1 df, P = 0.02; risk ratio = 0.68 (95% confidence interval; 0.50 to 0.93)). When cure was determined bacteriologically, the groups had similar rates (16/42 (38%) v 16/41 (39%); chi 2 = 0.02, 1 df, P = 0.89; risk ratio = 0.98 (0.70 to 1.39)).

CONCLUSIONS

Vitamin A reduces the severity of acute shigellosis in children living in areas where vitamin A deficiency is a major public health problem.

Clofilium-induced block of delayed rectifier type K+ current in atrial tumor cells (AT-1 cells)

Atrial tumor myocytes derived from transgenic mice (AT-1 cells) have been shown to express mRNAs encoding cardiac K+ channels and display a cardiac electrophysiological phenotype. The major K+ current is the rapid component of the delayed rectifier (I(kr)). The purpose of the study was to characterize the mode of action of a class III anti-arrhythmic agent (C3A), clofilium, in these cells to elucidate further the mechanism and functional consequence of block. We show that clofilium blocks this I(kr) in a dose-dependent manner with IC50 of 1.25 microM. Clofilium induced block was irreversible for higher concentrations (> or = 50 microM) and partially reversible for lower doses. The reversal potential for this current was -77.5+/-1.5 mV. The block is voltage dependent and the drug probably binds the channel in the open state.

Clinical and laboratory evaluation of powered electric toothbrushes: laboratory determination of relative abrasion of three powered toothbrushes

Previously established data on average forces applied to various brushing instruments during in vivo toothbrushing were incorporated into a laboratory abrasion model. The apparatus included a specially constructed and standardized brushing machine and utilized an acrylic resin substrate. Three powered brushing instruments (Rota-dent, Interplak and Braun Oral-B Plaque Remover) and a manual toothbrush (Oral-B P40), were compared in this model. The system demonstrated excellent precision and could distinguish between brushing instruments with as little as 10% difference in abrasivity. It was found that brushing abrasivity increased in the order of Rota-dent < Braun < Interplak.

Nuclear DNA content of fine needle aspirates of invasive ductal carcinomas of the breast

Patients with aggressive breast cancers benefit from chemotherapy prior to surgery. If the biology of the breast cancers were better characterised pre-operatively, more patients at risk could be offered chemotherapy. We have assessed nuclear DNA content of fine needle aspirates (FNA) of 103 invasive ductal breast cancers and compared this to tumour size, node status and histological grade. Median follow-up was 18 months so no prognostic studies were made. Diploid and non-diploid tumours were distributed equally in node negative and positive patients. However non-diploidy status increased in line with known prognostic markers of tumour size and histological grade. This suggests that ploidy might contribute to the pre-operative assessment of prognosis. We conclude that nuclear DNA of breast cancer FNAs may be of value in the pre-operative biological assessment of breast cancer patients.

Clinical and laboratory evaluation of powered electric toothbrushes: laboratory determination of relative interproximal cleaning efficiency of four powered toothbrushes

The clinical brushing data from the paper entitled, Clinical and Laboratory Evaluation of Powered Electric Toothbrushes: In Vivo Determination of Average Force for Use of Manual and Powered Toothbrushes, by Boyd et al. in this Special Issue, were incorporated into a laboratory cleaning model. Utilizing a standardized brushing machine and a methyl methacrylate substrate, four powered brushing instruments were tested for cleaning efficiency: Rota-dent. Braun Oral-B. Interplak and Sonicare, and a manual toothbrush (Oral-B P40). The Sonicare powered brushing instrument was tested at the manufacturer's recommended brushing force of 0.5 N as well as a calculated force of 1.0 N. The results showed that the Rota-dent was more efficient (p < 0.01-0.001) in removing stain from both flat and interproximal surfaces than any of the other tested brushes. These results, together with those reported by McLey, et al. in Clinical and laboratory Evaluation of Powered Electric Toothbrushes: Laboratory Determination of Relative Abrasion of Three Powered Toothbrushes in this Special Issue, demonstrate that the rotary action Rota-dent instrument has the most efficient combination of low abrasion and high cleaning efficiency of the four powered brushes and the manual brush when all instruments were tested using clinically documented pressures.

Clinical and laboratory evaluation of powered electric toothbrushes: relative degree of bristle end-rounding

Toothbrush bristles with sharp edges have been postulated to represent a greater threat to dental tissues than end-rounded bristles. This study evaluated the effect of both in vivo and laboratory use on bristle wear rate, tip geometry and in vitro abrasivity. Three soft manual brushes (Oral-B P40, Crest Complete and Butler GUM) and one powered brush (Rota-dent) were tested. The results of this study show that the wear rate varied directly with brushing load and amount of dentifrice, and inversely with bristle diameter. Despite the initial geometry, a flat tip with rounded rims was typically observed after only 30 minutes of manual or Rota-dent brush use. There was no statistical difference in in vitro abrasion for new brushes versus used brushes.

Ryanodine induced block of a cloned human cardiac potassium channel

The effects of ryanodine in a cloned human cardiac potassium channel (hKvl.5) expressed in a stable mouse L cell line was studied using whole cell voltage clamp technique. Ryanodine in a dose dependent manner (10(-7) - 10(-5) M) reduced the peak current as well as the current at the end of a 250 ms pulse. Dose response data fitted to a Hill equation yielded IC50 of 1.2 microM. The degree of block was not voltage dependent. Peak current was reduced from 43.6 +/- 12.5% at 10(-5) M to 11.3 +/- 4.8% at 10(-7) M ryanodine. Ryanodine reduced the tail current amplitude without changing the time course relative to the control. The inhibition was only partially reversible at concentrations below 10(-6) M.

Assessment of gastric acid output by H2 breath test

BACKGROUND

The standard method to measure gastric acid secretion is the aspiration of gastric juice. A noninvasive breath test after application of magnesium has been proposed. The aim of this study was to modify the method, to possibly improve the discriminatory value of the test in comparison with intubation tests.

METHODS

We measured the time course of the reaction of magnesium and gastric acid in vitro and determined the gastric hydrogen kinetics in humans by insufflation of hydrogen into the stomach and measuring its reappearance in the exhaled air. Thereafter, a comparison of the breath test and the intubation test was done in 10 healthy volunteers in different secretory states.

RESULTS

After hydrogen insufflation 31.4% reappeared in 90 min (16.3% exhaled, rest belched). Discriminant analysis showed that the intubation test had a good discriminatory power. On the other hand, the breath test failed to distinguish between different secretory states (stimulation, inhibition, and intermediate).

CONCLUSION

Whereas the intubation test discriminated between high and low acid secretion, the breath test did not. This test therefore seems, at least as performed here, unsuitable as a diagnostic test of gastric acid secretion.

Dextrose-, adenosine- and magnesium-induced protective actions during anoxia and reperfusion in canine Purkinje tissue

1. The effects of dextrose, magnesium (Mg) and adenosine on membrane potential and force of contraction were studied in driven and overdriven canine cardiac Purkinje tissue. 2. Dextrose (50 mmol/L) and adenosine (4-6 mmol/L) both showed protective action (the latter to a lesser extent) against simulated anoxia and reperfusion-induced arrhythmias, increased force of contraction transiently on reperfusion, and the former sustained the increase in force to a lower level as long as it was in the superfusing solution. 3. Dextrose (50 mmol/L) and Mg (5 mmol/L) restored overdrive-induced hyperpolarization during simulated anoxia. Adenosine was largely ineffective. 4. It was concluded that dextrose and adenosine (to a lesser extent) protect against arrhythmias by replenishing the critical intracellular pool of ATP which controls membrane transport of electrolytes such as K and Ca. Restoration of Na-K ATPase activity alone (as in the case of high Mg concentrations) is not sufficient to prevent arrhythmias.

Modulations of membrane potential oscillations with drive, calcium overload, ryanodine, and caffeine

The objective of this study is to determine the conditions that generate overdrive excitation and overdrive suppression in canine cardiac Purkinje tissue superfused in vitro. Drive-induced (3 Hz) perturbations in the membrane potential of a calcium overloaded (induced by strophanthidin) Purkinje fiber (from a canine heart) were differently modulated by caffeine and ryanodine. Whereas the postdrive oscillations in the membrane potential Vos (single or multiple oscillations in the diastole of the action potential) and/or spontaneous rate (postdrive suppression or postdrive excitation [PDE]) depended on the concentration of strophanthidin (PDE occurred at 2.5 x 10(-7) M, and Vos were seen variably at several concentrations), caffeine (2-3 mM) in the presence of a lower concentration of strophanthidin (1.25 x 10(-7) M) induced PDE. At these lower concentrations, either drug administered alone only induced Vos. On the contrary, the characteristic effects of ryanodine (10(-8) M) in the presence of strophanthidin (2.5 x 10(-7) M) were either a consistent postdrive suppression immediately or the induction of a pronounced afterdepolarization ([AD] a depolarization following the repolarization of the action potential) whose amplitude decreased with time and suppression. At higher concentrations of ryanodine (10(-5) M-10(-6) M) in a calcium overloaded tissue (strophanthidin, 1.25 x 10(-7) M) overdrive induced a pronounced AD in most cases, with subsequent depolarization and cessation of activity in less than 20 minutes. Ryanodine alone caused suppression of postdrive diastolic potential at lower concentrations (10(-9) M-10(-8) M), a pronounced AD (amplitude diminished with later drives), and suppression at higher concentrations (10(-6) M-10(-5) M).(ABSTRACT TRUNCATED AT 250 WORDS)