Xanthine oxidoreductase and chemosensitivity in non-small cell lung cancer

11077

Background: Xanthine oxidoreductase (XOR) is an enzyme involved in the degradation of purines into uric acid and reactive oxygen species and activation of the MAP kinase pathway involved in apoptosis. Decreased XOR expression was shown in recent studies to be associated with more aggressive disease in breast (Linder et al. Clin Cancer Res. 2005;11:4372–4381) and gastric cancers (Linder et al. J Clin Pathol. 2006;59:965–971). The goal of our study was to show that decreased XOR expression was associated with decreased survival in non-small cell lung cancer (NSCLC). Methods: Tissue specimens from 82 patients (pts) were stained using a XOR specific antibody (36 male and 46 female, age range from 40 to 92 years). These included 41 adenocarcinoma, 31 squamous cell, 8 poorly/moderately differentiated, and 2 bronchioloalveolar. XOR staining intensity was measured on a scale of 0 through 4 (0 being no staining). XOR intensity was correlated with clinical characteristics and outcomes using log rank and COX PH regression analysis. Results: Of the 82 pts, 34 received adjuvant chemo, and of these, 15 specimens had low XOR intensity (0–1). These 15 pts received adjuvant chemo and had a median survival of 543 days. In comparison, 19 of the 34 pts receiving adjuvant chemo had specimens with high XOR intensity (2–4). Their median survival was significantly longer at 2,023 days (p=0.007, hazard ratio=0.33). Conclusions: Although we had a small sample size, in our retrospective study, we found that pts who received adjuvant chemo had a longer survival if their tumors expressed high levels of XOR. XOR could be a potential predictor for responsiveness to adjuvant chemo in patients with NSCLC. Pts with decreased XOR may be less responsive to chemo and thus be able to avoid a toxic treatment if it is not significantly beneficial. [Table: see text]

No significant financial relationships to disclose.

PLX4032, a highly selective V600EBRAF kinase inhibitor: Clinical correlation of activity with pharmacokinetic and pharmacodynamic parameters in a phase I trial

9021

Background: PLX4032 is an oral, highly selective inhibitor of oncogenic V600EBRAF kinase currently in phase I trial. V600EBRAF mutation activates Raf/MEK/ERK pathway in multiple tumor types. We evaluated the relationship between PK, PD (pERK, Ki67, FDG-PET), tumor histology and clinical activity following PLX4032 administration in a phase I trial. Methods: In the phase I trial, 6 melanoma pts with V600EBRAF were treated with PLX4032 daily at several dose levels and tumor biopsies (baseline vs. day 15) were assessed histologically and by semi-quantitative IHC analysis (modified H-score) for pERK and Ki67. The first 4 pts received a crystalline formulation of PLX4032; the last 2 pts received a formulation with increased bioavailability. Plasma PK parameters were collected at frequent time points on Days 1, 8 and 15. FDG-PET was performed on Days 1 and 15 on last 2 pts. Results: In the first 4 pts, no histological changes were observed with treatment and all developed disease progression. All had decreased percentage of Ki67 positive nuclei (pre-Rx, range 20–60%, median 45%; post-Rx, range 5–25%, median 12.5%) and 3 of the 4 had decreased pERK levels (pre-Rx, range 50–100, median 60; post-Rx, range 10–40, median 11). Mean PLX4032 AUC0–24h ∼ 126 μM*h was in the range for preclinical tumor stasis but below the threshold for shrinkage. In the last 2 pts, striking tumor necrosis and tumor melanosis was observed in the post-Rx samples. One pt remains on study with a confirmed PR, the other showed a clinical response before disease progression occurred in cycle 2. The percentage of Ki67 positive nuclei declined substantially (pre-Rx, 30% and 50% to post-Rx, 5% and 3%), as did the levels of pERK in the pt with PR (pre-Rx: 70 to post-Rx: 2). Mean PLX4032 AUC0–24h was well above the preclinical threshold in the range of 500 - 1000 μM*h. Both pts had decreased FDG uptake on D15. Conclusions: Clinical activity of PLX4032 treatment correlates with drug exposure levels as measured by AUC0–24h and was associated with histological changes in V600EBRAF positive melanomas on Day 15. Reduction of pERK, along with evidence of reduced proliferation and FDG uptake was observed. Further analysis of PD markers with additional pts at the MTD is planned.

[Table: see text]

Phase I dose-escalation study of thoracic radiotherapy in combination with gefitinib in patients with IIIB/IV non-small cell lung cancer (NCT00497250)

e14581

Background: Cinical studies have confirmed that gefitinib, an EGFR-TKI, is effective for some advanced NSCLC patients. Patients with Asian ethnicity are reported to have a higher response rate with gefitinib monotherapy. However, a higher incidence of interstitial lung disease, sometimes lethal, is also found. The combination of gefitinib and radiotherapy has been observed to have a synergistic, anti-proliferative effect against NSCLC in vitro. This phase I study assessed the safety, clinical feasibility and optimally tolerated regimen (OTR) of this combination in patients with pretreated locally advanced or metastatic (IIIB/IV) NSCLC. Methods: Patients with stage IIIB or selected stage IV, failure of platinum-based chemotherapy regimen NSCLC were eligible. Four Cohorts of eight patients each were planned to be treated with escalating doses from 54 to 60 Gy of conformal or intensity- modulated radiotherapy (2Gy/Fx) administered in combination with gefitinib 250mg daily during RT and 60 days after the completion of RT to determine the OTR. Results: Since June 2007, 2 cohorts, a total of 16 patients, were enrolled and treated: 8 stage IIIB and 8 stage IV; 2 squamous-cell carcinoma and 14 adenocarcinoma; 8 smokers and 8 nonsmokers. Prior-chemotherapy regimen was consisted of NP, GP and TP for a median of 3.5 cycles (range, 1–5). Median follow-up time was seven months. Mean progression-free survival time was 5.2 months (median, 3.9; range, 1.7–12.3). Overall, adverse events were mild to moderate in severity. The most frequent grade 2 events included pneumonitis (31%) and dysphagia (19%). There were one treatment-related grade 3 event, which was nausea, and no grade 4 events. Most of the failure patterns were out-of-field (11/13) and the most common distant metastasis organ was the lungs. Three patients are progression-free to date. Conclusions: Thoracic radiotherapy up to 56 Gy concurrent with gefitinib 250 mg daily was well tolerated and clinically active in this group of pretreated Chinese NSCLC patients, including nonsmokers with adenocarcinoma. Accrual is continuing. Sponsorship: This work was partly supported by Program for New Century Excellent Talents in University (NCET), Ministry of Education.

No significant financial relationships to disclose.

Ki67 as a prognostic biomarker for patients with vertical growth phase (VGP) melanomas

9043

Background: In VGP melanomas proliferation is reflected in dermal mitotic figures (“mitogenic” VGP) and/or tumor cell nests larger than any epidermal nest. An alternative to mitotic rate (MR) to characterize cell proliferation is the expression of Ki67 protein. Since Ki67 is expressed in all phases of the cell cycle except G0, it is potentially a more robust biomarker for proliferation and prognosis than mitoses. Methods: To test the hypothesis that Ki67 would replace MR as a prognostic factor, we did a retrospective cohort study of 432 patients with Stage I/II primary VGP melanomas who had at least 10 years of follow up. Tissue sections were stained using the monoclonal antibody MIB-1 to Ki67 and the % of positive melanoma cells were evaluated by two readers. ROC curves for Ki67 and MR were computed. Predicted probabilities (PP) of 10-year melanoma-specific death were computed from 3 multivariate logistic regression models, one for each biomarker (Models 1 and 2) and one with both (Model 3), controlling for established melanoma prognostic factors (thickness, gender, anatomic site, ulceration, regression and tumor infiltrating lymphocytes), and compared. Cross-validation was used to assess differences between using Ki67 and using MR including the differences in PP, Brier scores and the misclassification rates. A decision curve analysis was done to assess the clinical net benefit of the two. Results: The areas under the ROC curve (AUCs) for Ki67 and MR, both continuous factors, were 0.69 and 0.79, respectively. In the multivariate analysis, Ki67 expression was significant in Model 1 (OR=1.03, 95% CI: 1.01–1.05), mitotic rate was not significant in Model 2 (1.05, 0.99–1.1), and only Ki67 was significant in Model 3 (1.03, 1.01–1.05). The AUCs for the three models were 0.84, 0.84, and 0.85, respectively. Based on cross-validation, there was no difference between the two biomarkers in PP, Brier scores, or misclassification rates. The decision cost analysis demonstrated the same net benefit for the two. Conclusions: A prospective study needs to be conducted to confirm that Ki67 and MR are equivalent.

No significant financial relationships to disclose.

The prognostic significance of lymphatic invasion in primary melanoma

9050

Background: Lymphatic invasion (LI) is an under-observed phenomenon in primary malignancies that can be better detected by immunostaining and that may associate with prognosis. In this study we sought to test the hypothesis that LI was associated with melanoma-specific survival (MSS) and was an independent prognostic factor. Methods: This study included 277 patients with stage I/II melanomas in vertical growth phase (VGP) who had at least 10 years of follow up. The log-rank test was used to test the study hypothesis - 72 melanoma-specific deaths were needed for 80% power to detect an odds ratio of 2.1. Paraffin sections were stained with antibodies to podoplanin (lymphatic vessels) and S-100 (melanoma cells) to identify LI. Univariate and multivariate Cox models were used to evaluate the prognostic significance of LI. An independent cohort of 106 similar patients was used for validation of the 10-year MSS rates. Results: LI was observed in 44.5% (95% CI: 38.6% - 50.4%) of the melanomas and its presence was significantly associated with thickness, mitotic rate, gender, age, and ulceration (U). The Kaplan-Meier survival curves for those with and without LI were significantly different (log-rank test p=0.022). The final multivariate model for time to MSD identified 4 independent prognostic factors: thickness (HR=1.5, p<0.001), U (HR=2.2 p=0.013), site (HR=3.9, p<0.001) and LI (HR=1.9, p=0.015). These factors were used to define a prognostic tree with 5 risk groups defined by melanomas that were thin (≤1.0mm) with no LI or U; thin with LI but no U; 1–3mm with no U; 1–3mm with U; and >3mm. Respectively, MSS rates were 100%, 88.6%, 77%, 48% and 42%. In the validation set, observed 10-year MSS rates in each risk group were not significantly different from those predicted from the survival curves for the tree-based risk groups. Conclusions: LI is an independent prognostic factor for MSS. Among patients with thin melanomas without U the 10-year MSS was lower for those patients with LI (89%, 95% CI=78% - 99%; n=41) compared to those without (100%, n=78). LI is an important prognostic factor that needs further validation in a population of patients from the sentinel node biopsy era.

No significant financial relationships to disclose.

Effect of metronomic use of zoledronic acid (ZOL) on antitumor and antiosteoclastic effects in breast cancer patients with bone metastasis

e14603

Background: Zoledronic acid (ZOL) can reduce the risk of skeletal-related events (SREs) and may have direct and indirect antitumor effects, which have been shown in animal models, pilot clinical studies as well as in recent phase III randomized trials. However, the pharmacokinetics of the drug in breast cancer patients remains to be elucidated and optimized. The purpose of this randomized study was to compare the effects of ZOL on osteoclasts and angiogenesis between a weekly low-dose versus a conventional dosage. Methods: Sixty breast cancer patients with bone metastases were recruited in this randomized phase II clinical study. The participants either received ZOL 1mg IV weekly for 4 doses or a single dose of ZOL 4mg IV. No other antitumor treatments were administered. During the first month after initial infusion of ZOL, serial blood samples were collected on day 1, 15 and 29 measuring markers for bone resorption (NTx), angiogenesis (VEGF), and tumor burden (CEA and CA15–3). Results: Compared to a single-dose administration, weekly low dose of ZOL resulted in a greater reduction in serum levels of VEGF and NTx, with a significant trend over time during one month observation. There were no statistically significant differences in circulating levels of CEA and CA15–3 between the two dosing regimens. Patients who received metronomic ZOL had a longer median time to disease progression (TTP) (7.0 months, 95%CI, 6.1–7.9 months) than those who had a single dose of ZOL (2.8 months, 95%CI, 0–5.7 months; p=0.076). Conclusions: The metronomic use of low-dose ZOL 1 mg appeared to be more effective than the conventional regimen in the long-lasting reduction of VEGF and NTx, and in prolonging TTP. This dosing schedule should be further assessed in phase III trials as we demonstrated that ZOL 1mg has greater antitumor properties in our study.

No significant financial relationships to disclose.

Use of peripheral blood genomic markers whose expression levels reflect that of breast tumor genomic markers to predict drug treatment and sensitivity

3588

Background: Tumor gene expression signatures have been used to predict drug response, and we have previously reported drug-induced signatures to be more informative than the untreated baseline signatures. However, repeated tumor sampling during treatment is not feasible for most patients. We studied peripheral mononuclear cell (PBMC) gene expression levels in association with tumor gene expression levels in an attempt to identify peripheral blood markers that may serve as more accessible surrogates to predict drug treatment and response. Methods: Chemonaive breast cancer patients were treated with an alternating sequential regimen of doxorubicin and docetaxel and randomized to start with either drug. RNA from primary tumor before and 3 weeks, and from PBMC before and 24 hours after the first cycle of each drug was hybridized on the Affymetrix HG-U133+2 array containing 54,675 probe sets. Results: Pre- and post-treatment tumors from 47 patients were studied, including 35 with paired PBMC samples. 230 pre- and 85 posttreatment PBMC probe sets showed strong correlation in expression level (Pearson correlation coefficient >0.9) with the corresponding pre- and posttreatment tumor probe set, and included genes involved in transcription regulation and binding. Of the 975 tumor probe sets whose changes distinguished doxorubicin from docetaxel treatment, 12 corresponding PBMC probe sets were identified (p < 0.001) whose changes at 24 hours distinguished the two treatments with 77% accuracy. Of the 1,081 and 1,526 tumor probe sets whose changes predicted treatment response to doxorubicin and docetaxel, 19 and 15 informative PBMC probe sets predicted response to each drug with 100% and 80% accuracy, and included TNF receptor associated protein 1 and trefoil factor 1 for doxorubicin-, and folliculin and dynein for docetaxel-response. When the PBMC probe sets were validated in an independent test set treated with docetaxel (n = 23), 87% was correctly classified as docetaxel-treated, while 89% of non-responders clustered together. Conclusions: Peripheral blood contains genomic markers whose expression levels closely reflect that of breast tumor markers, and may be promising as surrogates to predict drug treatment and sensitivity.

No significant financial relationships to disclose.

Standardising analogue front end design for ultrasound imaging systems

The standardisation of analogue front end products is allowing the development of portable ultrasound devices that provide enhanced image quality while minimising power consumption. The design opportunities associated with the use of these products are described.

MR imaging findings of the uveal schwannoma

BACKGROUND AND PURPOSE

Uveal schwannoma is a rare benign neoplastic proliferation of pure Schwann cells. The purpose of this study was to describe MR imaging features of uveal schwannoma.

MATERIALS AND METHODS

MR images in 6 female patients with uveal schwannoma confirmed by pathologic examination were retrospectively reviewed. MR imaging was performed in all 6 patients, with postcontrast T1-weighted imaging (T1WI) completed in all 6 patients and dynamic contrast-enhanced MR imaging, in 5. MR imaging findings of the tumor were evaluated with emphasis on the location, size, shape, margin, signal intensity, and pattern of enhancement.

RESULTS

The lesions appeared as solitary well-defined ovoid masses in the ciliochoroidal region in 5 patients and in the choroid in 1. With respect to the vitreous body, uveal schwannoma was hyperintense on T1WI spin-echo (SE) images in all 6 patients. The tumors were hypointense to the vitreous body on fast SE (FSE) T2-weighted images (T2WI) in 4 patients and isointense in 1. However, with respect to the brain, uveal schwannoma demonstrated isointensity on T1WI SE images in all 6 patients, isointensity on FSE T2WI images in 5 patients, and hyperintensity on T2WI SE images in 1. On postcontrast T1WI images, 3 patients showed markedly heterogeneous enhancement, and 3 showed markedly homogeneous enhancement.

CONCLUSIONS

Uveal schwannoma should be included in the differential diagnosis when an oval isointense mass relative to brain is seen in the ciliochoroidal region.

Hydrogen peroxide reduces lead-induced oxidative stress to mouse brain and liver

Lead (Pb) intoxication may initiate many disorders in human and animals. This study investigates the role of exogenous hydrogen peroxide (H(2)O(2)) in inducing mouse tolerance to Pb exposure. Results showed that the simultaneous application of 1.2 microg H(2)O(2) per kg body weight efficiently protected mice against the Pb-caused injury, as revealed by decreased growth suppression caused by the Pb stress, increased antioxidative enzyme activity, reduced lipid peroxidation, and the protective effect on the nuclear DNA integrity. To our knowledge, this is the first finding of this sort.

The effects of proteasome inhibitor bortezomib on a P-gp positive leukemia cell line K562/A02

The aim of this study is to clarify the efficacy of proteasome inhibitor bortezomib to multidrug resistant (MDR) acute leukemia cells. We observed the effects of bortezomib on a P-glycoprotein (P-gp) positive leukemia line K562/A02. The results showed that bortezomib has significant effects on P-gp positive K562/A02 cells including cytotoxicity (48 h IC(50): 171.36 nM), induction of apoptosis (31.71 +/- 1.07% apoptotic cells after 24 h treatment at 100 nM), and inhibition of proteasome chymotrypsin-like activity (relative activity to untreated controls: 20.07 +/- 0.66% at 24 h with 10 nM bortezomib). These effects were lower than those observed in K562 cells (IC(50), percentage of apoptotic cells, relative chymotrypsin-like activity to untreated controls were 56.28 nM, 77.95 +/- 0.35%, 5.35 +/- 2.05% after the same treatments, respectively). No synergy between daunorubicin and bortezomib was shown in the killing of K562/A02 cells (synergistic ratios were <1). P-gp expression levels did not decrease in K562/A02 cells after bortezomib treatment. Pretreatment with bortezomib does not improve the intracellular anthracycline concentration in K562/A02 cells. Bortezomib shows a promising effect for the treatment of refractory/relapsed leukemia, but it does not improve the effect of anthracycline to MDR leukemia cells.

A giant facial nerve schwannoma extending from the middle cranial fossa to the mastoid region: case report

Facial nerve schwannomas are uncommon benign tumours and seldom extend into the middle cranial fossa. This is a case report of a giant facial nerve schwannoma extending from the middle cranial fossa to the mastoid region, which was successfully removed using combined interdisciplinary subtemporal and transmastoid approaches. Complete resection of the tumour was the optimal therapy for this patient because the facial nerve had been severely destroyed by the tumour. The clinical presentation, histological features, radiological findings and management of this case, as well as the relevant literature, are presented.

Novel F-releasing composite with improved mechanical properties

In recent years, the authors have been developing novel fluoride-releasing dental composites containing ternary zirconium fluoride chelates. The aim of this study was to improve the physical and mechanical properties of these composites by improving the formulation of the monomers and photoinitiators. The hypothesis was that reduction of hydrophilic monomers and improvement of the photoinitiators could reduce water sorption and significantly increase the mechanical properties of the composite. The degree of conversion of the composites containing different compositions of photoinitiators was studied by Fourier transform near-infrared spectroscopy (FT-NIR). Ten experimental composites containing different compositions of ethoxylated bisphenol-A dimethacrylate (EBPADMA), 1,6-hexanediol dimethacrylate (HDDMA), triethylene glycol dimethacrylate (TEGDMA), and 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy) phenyl]-propane (BisGMA) were tested for flexural strength, viscosity, and water sorption. The experimental composite containing 20% synthesized fluoride-releasing monomer, 30% BisGMA, 30% EBPADMA, and 20% HDDMA showed significantly higher fluoride release and recharge, but physical and mechanical properties similar to those of the control composite containing 40% BisGMA, 40% EBPADMA, and 20% HDDMA.

Modelling of processes governing subcellular localisation of MinD in Escherichia coli

Recent research has highlighted several examples wherein bacterial cell fate is determined by precise subcellular localisation of proteins. A prominent example is the polar localisation and oscillation of the Min proteins which is necessary for accurate cell division in Escherichia coli. Several computational models have been proposed which reproduce the oscillatory behaviour and observed phenotypes. However, these models use varying assumptions to do so leading to different mechanisms for precise polar localisation of MinD zones. To gain further insight, the authors extend a simplified model which focused on some key processes to explain the observed length scale for MinD zone formation. Using analytical approaches and numerical simulations, the authors explore cellular MinD distributions produced by these processes and propose a mechanism for precise polar localisation of MinD.

Electron tomography of regularly shaped nanostructures under non-linear image acquisition

Electron tomography allows the 3D quantitative characterization of nanostructures, provided a monotonic relationship is fulfilled between the projected signal and the atomic number and thickness of the specimen. This requirement is not satisfied if the micrographs are affected by (i) diffraction contrast, (ii) detector saturation or (iii) contrast inversion due to absorption (high-angle scattering) at high thickness. Artefacts related to the non-monotonic tomography acquisition are examined using computer simulations and experimental tilt series of tungsten tips and CeO(2) nanoparticles. Conditions are derived under which in spite of the non-linear artefacts the information is sufficient for reconstructing the 3D morphology of convex objects by geometric tomography.

Association of ADHD with genetic variants in the 5'-region of the dopamine transporter gene: evidence for allelic heterogeneity

Multiple studies have reported an association between attention deficit hyperactivity disorder (ADHD) and the 10-repeat allele of a variable number tandem repeat (VNTR) polymorphism in the 3'-untranslated region (3'UTR) of the dopamine transporter gene (DAT1). Yet, recent meta-analyses of available data find little or no evidence for this association; although there is strong evidence for heterogeneity between datasets. This pattern of findings could arise for several reasons including the presence of relatively rare risk alleles on common haplotype backgrounds or the functional interaction of two or more loci within the gene. We previously described the importance of a specific haplotype at the 3' end of DAT1, as well as the identification of associated single nucleotide polymorphisms (SNPs) within or close to 5' regulatory sequences. In this study we replicate the association of SNPs at the 5' end of the gene and identify a specific risk haplotype spanning the 5' and 3' markers. These findings indicate the presence of at least two loci associated with ADHD within the DAT1 gene and suggest that either additive or interaction effects of these two loci on the risk for ADHD. Overall these data provide further evidence that genetic variants of the dopamine transporter gene confer an increased risk for ADHD.