Adjuvant Chemotherapy for Non-Small Cell Lung Cancer

Nearly half of all patients who undergo surgical resection of localized non-small cell lung cancer (NSCLC) will develop and ultimately die of recurrent disease. The postoperative radiotherapy (PORT) meta-analysis showed adjuvant thoracic radiotherapy to have a detrimental effect on survival in this patient population. A meta-analysis of early trials of adjuvant chemotherapy by the Non-Small Cell Lung Cancer Collaborative Group showed that while chemotherapy with alkylating agents was also detrimental, chemotherapy with cisplatin-based adjuvant chemotherapy was associated with an improved hazard ratio for death (HR = 0.87), equating to a 5 percent survival benefit at 5 years. However, the result was not statistically significant (p = 0.08). Recently, results have been reported for several large Phase III trials of adjuvant chemotherapy which differed with respect to the stage of resected disease included, the type of chemotherapy used and the use of post-operative radiotherapy. Three trials (IALT, JBR 10, and ANITA) that utilized cisplatin-based doublets showed a significantly positive survival benefit of adjuvant chemotherapy in patients with Stage II-IIIA NSCLC. The magnitude of this benefit, which was suggested to be 4-5 percent at 5 years in the meta-analysis and by the IALT study, may be as large as 8-15 percent as indicated by more recent studies with modern platinum-based doublet chemotherapy. These data indicate that medically fit patients with resected Stage II-IIIA NSCLC should be offered adjuvant chemotherapy with a modern cisplatin-based doublet.

Clinical activity observed in a phase I dose escalation trial of an oral c-met and ALK inhibitor, PF-02341066

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Background: PF-02341066 (PF) is a selective, ATP-competitive, small molecule oral inhibitor of the c-Met/HGFR and ALK receptor tyrosine kinases that has not previously been tested in humans. A Phase 1 dose-escalation trial evaluating PF as an oral single agent was conducted to investigate safety, PK and PD in patients (pts) with advanced cancer (excluding leukemias). Methods: PF was administered under fasting conditions QD or BID on a continuous schedule to pts in successive dose-escalating cohorts at doses ranging from 50 mg QD to 300 mg BID. Pts with advanced cancer were enrolled in the study. Results: Thirty-seven pts were enrolled into the dose escalation part of the study. Tumor types included colorectal, pancreatic, sarcoma, ALCL and NSCLC. The MTD was 250 mg BID. Three DLTs were observed: grade 3 increase in ALT (1 pt at 200 mg QD) and grade 3 fatigue (2 pts at 300 mg BID). The most common AEs were nausea, emesis, fatigue and diarrhea. Nausea and emesis were independent of dose or duration of treatment. Mean AUC (30–57% CV) and Cmax (36–69% CV) increased proportionally with dose from 100 mg QD to 300 mg BID. The median terminal half-life was 46 hours. A 2- to 4-fold increase in the oral midazolam (MDZ) AUC was observed following 28-days of PF dosing at 100 mg QD (n = 3) and 300 mg BID (n = 2), respectively, suggesting PF to be an inhibitor of CYP3A. Ten pts have entered an enriched RP2D cohort of pts with tumors harboring c-Met amplification/gene mutation or ALK fusion genes. There has been 1 confirmed PR in a sarcoma pt with ALK rearrangement (inflammatory myofibroblastic tumor). Among 10 NSCLC pts whose tumors harbor EML4-ALK rearrangement, 1 pt has had a PR, 2 pts have achieved unconfirmed PR and 4 pts have had SD (3 have experienced reduction in tumor burden by ∼20% in measurable lesions and 1 has been treated for 28 weeks). Conclusions: The MTD of PF is 250 mg BID. The major AEs were fatigue or GI-related, and all AEs were manageable and reversible. There was no evidence of non-linear PK at PF doses >100 QD. Treatment with PF-02341066 resulted in promising clinical activity against tumors carrying activating ALK gene rearrangements. Further study of PF in pts with ALK-dependent tumors is warranted.

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Tpl2 kinase regulates T cell interferon-gamma production and host resistance to Toxoplasma gondii

Tpl2 (Tumor progression locus 2), also known as Cot/MAP3K8, is a hematopoietically expressed serine-threonine kinase. Tpl2 is known to have critical functions in innate immunity in regulating tumor necrosis factor–α, Toll-like receptor, and G protein–coupled receptor signaling; however, our understanding of its physiological role in T cells is limited. We investigated the potential roles of Tpl2 in T cells and found that it was induced by interleukin-12 in human and mouse T cells in a Stat4-dependent manner. Deficiency of Tpl2 was associated with impaired interferon (IFN)-γ production. Accordingly, Tpl2^−/− mice had impaired host defense against Toxoplasma gondii with reduced parasite clearance and decreased IFN-γ production. Furthermore, reconstitution of Rag2^−/− mice with Tpl2-deficient T cells followed by T. gondii infection recapitulated the IFN-γ defect seen in the Tpl2-deficient mice, confirming a T cell–intrinsic defect. CD4⁺ T cells isolated from Tpl2^−/− mice showed poor induction of T-bet and failure to up-regulate Stat4 protein, which is associated with impaired TCR-dependent extracellular signal-regulated kinase activation. These data underscore the role of Tpl2 as a regulator of T helper cell lineage decisions and demonstrate that Tpl2 has an important functional role in the regulation of Th1 responses.

Detection of the transforming AKT1 mutation E17K in non-small cell lung cancer by high resolution melting

Background

A recurrent somatic mutation, E17K, in the pleckstrin homology domain of the AKT1 gene, has been recently described in breast, colorectal, and ovarian cancers. AKT1 is a pivotal mediator of signalling pathways involved in cell survival, proliferation and growth. The E17K mutation stimulates downstream signalling and exhibits transforming activity in vitro and in vivo.

Findings

We developed a sensitive high resolution melting (HRM) assay to detect the E17K mutation from formalin-fixed paraffin-embedded tumours. We screened 219 non-small cell lung cancer biopsies for the mutation using HRM analysis. Four samples were identified as HRM positive. Subsequent sequencing of those samples confirmed the E17K mutation in one of the cases. A rare single nucleotide polymorphism was detected in each of the remaining three samples. The E17K was found in one of the 14 squamous cell carcinomas. No mutations were found in 141 adenocarcinomas and 39 large cell carcinomas.

Conclusion

The AKT1 E17K mutation is very rare in lung cancer and might be associated with tumorigenesis in squamous cell carcinoma. HRM represents a rapid cost-effective and robust screening of low frequency mutations such as AKT1 mutations in clinical samples.

Clinical activity of pemetrexed: a multitargeted antifolate anticancer agent

Pemetrexed is a new generation antifolate anticancer agent that inhibits several folate-dependent enzymes required for production of DNA and RNA intermediates. Early studies showed significant hematologic and nonhematologic toxicities with this agent. However it was found that many of these toxicities related to functional folate status and could be markedly reduced through routine supplementation with folic acid and vitamin B(12), without adversely affecting efficacy. Phase III studies with pemetrexed have established a clinical role for this drug as a single agent in the second-line treatment of non-small cell lung cancer and in combination with cisplatin for the frontline treatment of unresectable malignant pleural mesothelioma. Clinical trials of pemetrexed alone or in combination with other chemotherapeutic agents have shown considerable activity in many tumor types including colorectal, pancreatic and breast cancer, and urothelial tumors.

Mass spectrometry to classify non-small-cell lung cancer patients for clinical outcome after treatment with epidermal growth factor receptor tyrosine kinase inhibitors: a multicohort cross-institutional study

BACKGROUND

Some but not all patients with non-small-cell lung cancer (NSCLC) respond to treatment with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). We developed and tested the ability of a predictive algorithm based on matrix-assisted laser desorption ionization (MALDI) mass spectrometry (MS) analysis of pretreatment serum to identify patients who are likely to benefit from treatment with EGFR TKIs.

METHODS

Serum collected from NSCLC patients before treatment with gefitinib or erlotinib were analyzed by MALDI MS. Spectra were acquired independently at two institutions. An algorithm to predict outcomes after treatment with EGFR TKIs was developed from a training set of 139 patients from three cohorts. The algorithm was then tested in two independent validation cohorts of 67 and 96 patients who were treated with gefitinib and erlotinib, respectively, and in three control cohorts of patients who were not treated with EGFR TKIs. The clinical outcomes of survival and time to progression were analyzed.

RESULTS

An algorithm based on eight distinct m/z features was developed based on outcomes after EGFR TKI therapy in training set patients. Classifications based on spectra acquired at the two institutions had a concordance of 97.1%. For both validation cohorts, the classifier identified patients who showed improved outcomes after EGFR TKI treatment. In one cohort, median survival of patients in the predicted "good" and "poor" groups was 207 and 92 days, respectively (hazard ratio [HR] of death in the good versus poor groups = 0.50, 95% confidence interval [CI] = 0.24 to 0.78). In the other cohort, median survivals were 306 versus 107 days (HR = 0.41, 95% CI = 0.17 to 0.63). The classifier did not predict outcomes in patients who did not receive EGFR TKI treatment.

CONCLUSION

This MALDI MS algorithm was not merely prognostic but could classify NSCLC patients for good or poor outcomes after treatment with EGFR TKIs. This algorithm may thus assist in the pretreatment selection of appropriate subgroups of NSCLC patients for treatment with EGFR TKIs.

Contribution of Ara h 2 to peanut-specific, immunoglobulin E-mediated, cell activation

BACKGROUND

Ara h 2 is a potent peanut allergen but its contribution to the ability of a crude peanut extract (CPE) to cross-link IgE and activate mast cells has not been rigorously evaluated.

OBJECTIVE

To measure the contribution that Ara h 2 makes to the effector function of a CPE.

METHODS

Ara h 2 was specifically removed from a CPE as demonstrated by immunoblots, 2D gels, and an inhibitory ELISA. Functional assays of sham-treated and Ara h 2-depleted CPEs were performed with RBL SX-38 cells sensitized with IgE from highly peanut-allergic subjects and with naturally sensitized basophils.

RESULTS

Depletion of approximately 99% of the Ara h 2 from the CPE led to an increase in the concentration of the CPE necessary to give 50% of maximal degranulation (EC50) of the SX-38 cells following sensitization with sera that contain anti-Ara h 2 IgE. Assays with a pool of 10 sera showed a small but significant increase in the EC50 following depletion of Ara h 2 (1.65+/-0.15-fold; P<0.05) and assays of seven individual sera showed a similar increase in the average EC50 (1.7+/-0.2-fold; P<0.02). The percent of the anti-peanut IgE that binds Ara h 2 correlated with an increase in the EC50 of the CPE following depletion of Ara h 2 (r=0.83; P<0.02). On the other hand, data from three of these patients studied with a basophil histamine release assay did not show a significant effect of depletion of Ara h 2.

CONCLUSION

Based on its ability to cross-link IgE effectively, Ara h 2 is clearly an important peanut allergen. Its ability to cross-link IgE effectively from a specific serum is related to the proportion of anti-Ara h 2 in that serum but Ara h 2 does not account for a majority of the effector activity of the CPE for any of the sera studied.

Effect of Visual Feedback on Surgical Performance Using the da Vinci® Surgical System

BACKGROUND

Robotic surgical systems quantify human movements in terms of position, velocity, and time span. This information can be used to objectively assess surgical skill. The aim of this study was to test the effects of three-dimensional vs. two-dimensional visualization on performance using the da Vinci Surgical System (Intuitive Surgical, Sunnyvale, CA).

MATERIALS AND METHODS

The movements of novice and expert surgeons were recorded using the da Vinci Surgical System for a two-handed task in two visual environments (two-dimensional and three-dimensional). Data were analyzed to investigate the effect of visual feedback on performance.

RESULTS

Velocities and task completion times were significantly different for novices and experts (P < 0.05) for all velocity parameters in both visual conditions. Additionally, there was a significant difference between two-dimensional and three-dimensional times for novices (P < 0.05). Novices were idle significantly longer in two-dimensional than in three-dimensional visual input (P = 0.037), and overall, novices were idle longer than experts for both visual conditions (P = 0.001).

CONCLUSION

Three-dimensional visual input allows novice surgeons to perform tasks with higher velocities, less idle time, and greater economy of motion. However, three-dimensional visual input provides no significant enhancement of performance for expert surgeons.

Prediction of clinical outcome in non-small cell lung cancer (NSCLC) patients treated with gefitinib using Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) of serum

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Background: Assessment of epidermal growth factor receptor (EGFR) gene copy number, mutational status, and protein levels may predict response and possibly survival following treatment with EGFR tyrosine kinase inhibitors, but all these methods require tumor tissue, highlighting the need for a non-invasive predictive test. We evaluated the ability of MALDI-TOF MS profiling of serum to predict which patients (Pts) with NSCLC were likely to benefit from gefitinib treatment. Methods: Serum from Pts with NSCLC, collected prior to treatment with gefitinib, was subjected to MALDI-TOF MS using Voyager DE-STR or DE-PRO instruments. Replicate mass spectra obtained at two institutions were submitted to a third party for processing (background subtraction, noise estimation, normalization, spectral alignment and peak identification) and selection of discriminating mass/charge (m/z) values from a training cohort of 70 Caucasian Pts. The predictive capability of the profile was then assessed in independent cohorts of NSCLC Pts. Results: Intra- and inter- laboratory reproducibility of MALDI spectra were excellent. A set of 11 m/z values (mass range 5 - 12.5 kDa) predictive of clinical benefit were identified in the training cohort and confirmed by leave-one-out cross validation. Spectra from 19/70 Pts in the training cohort were unclassifiable. For the remaining 51 Pts the algorithm discriminated groups more or less likely to benefit with respect to time to progression (median 3.0 vs. 1.5 mo., p = 0.0325) and overall survival (median 14.6 vs. 2.3 mo., p = 0.0128). Validation was performed in an independent cohort consisting of serum from 69 Japanese Pts. Spectra from 13/69 Pts were unclassifiable. For the remaining 56 Pts it was possible to identify a group with superior time to progression (median 14.8 vs. 2.1 mo., p = 0.0012) and overall survival (median 19.1 vs. 7.9 mo., p = 0.0102). Conclusions: MALDI-TOF MS of pretreatment serum may aid with the identification of subsets of NSCLC Pts that will benefit from treatment with gefitinib. This algorithm is currently being evaluated in an expanded cohort of Pts receiving gefitinib treatment and in Pts treated with erlotinib.

[Table: see text]

The influence of efaproxiral on breast cancer xenograft hypoxia and HIF-1-alpha expression

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Background: Efaproxiral (E), a synthetic allosteric modifier of hemoglobin, has demonstrated clinical safety and efficacy as a radiosensitizer in patients with brain metastases from breast cancer. Although shown to enhance oxygenation in a murine mammary tumor, efaproxiral has not previously been tested in a human breast cancer xenograft. We studied changes in tumor oxygenation in a human xenograft and evaluated whether efaproxiral induces cell signaling events of potential therapeutic value. Methods: MDA-MB-468 breast cancer cells in matrigel were injected into the flank of nude mice. After tumors grew to 1–1.5 cm, animals were subjected to 1 of 3 treatments: ip saline +room air breathing (RA), ip saline + 50% oxygen breathing (O2), or ip efaproxiral (300 mg/kg) + 50% oxygen breathing (E+O2). Twenty minutes later the hypoxia marker, pimonidazole (pimo), was given, and 70 minutes later tumors were harvested for immunohistochemical study of hypoxia and hypoxia-inducible factor 1-alpha (HIF1-α) and RNA extraction to identify early changes in gene expression. Image analysis software was used to quantify observations. Results: Tumor hypoxia and HIF1-α staining were significantly decreased by efaproxiral (Table). HIF1-α staining did not entirely colocalize with pimo, implying different oxygen tension levels for HIF1-α ubiquitination and pimo reduction. Gene arrays indicated that after E+O2, expression of the hypoxia-induced DR1 transcription repressor was reduced compared with O2. Conclusions: The combination of E+O2 reduced hypoxia and HIF1-α expression in MDA-MB-468 human breast tumors in vivo, and an early effect on gene expression was reduced DR1. The results demonstrate an efaproxiral-mediated enhanced oxygenation of human hypoxic breast cancer. Furthermore, the efaproxiral-mediated down-regulation of HIF1-α suggests possible new opportunities in the clinical application of efaproxiral, notably as an adjuvant to systemic agents for which HIF1-α-mediated resistance limits efficacy.

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Modulation of intratumoral hypoxia by the epidermal growth factor receptor inhibitor gefitinib detected using small animal PET imaging

Blockade of signaling through the epidermal growth factor receptor (EGFR) tyrosine kinase by inhibitors such as gefitinib (Iressa) can inhibit tumor angiogenesis and enhance responses to ionizing radiation. In this study, the ability of gefitinib to modulate intratumoral oxygenation was evaluated in human EGFR-expressing A431 squamous cell carcinoma xenografts using in vivo small animal positron emission tomography (PET) imaging with the hypoxia marker [(18)F]fluoroazomycin arabinoside (FAZA) and by the immunohistochemical detection of hypoxia-induced adducts of the 2-nitroimidazole, pimonidazole. Serial noninvasive PET imaging of A431 xenografts showed a significant reduction in FAZA uptake following treatment with 75 mg/kg/d of gefitinib [tumor to background ratio, 6.1 +/- 1.0 (pretreatment) versus 2.3 +/- 0.6 (posttreatment); P = 0.0004]. Similarly, ex vivo quantitation of FAZA uptake showed significantly reduced FAZA uptake in established A431 xenografts treated with gefitinib compared with vehicle control (tumor to blood ratio for controls versus gefitinib, 8.0 +/- 3.0 versus 2.7 +/- 0.8; P = 0.007; or tumor to muscle ratio controls versus gefitinib, 8.6 +/- 2.8 versus 2.6 +/- 1.0; P = 0.002). The effect of gefitinib treatment seemed to be independent of tumor size. In addition, gefitinib treatment reduced pimonidazole-binding in A431 xenografts measured after 5 and 8 days of gefitinib treatment compared with baseline and with tumors treated with vehicle alone. A strong correlation was observed between pimonidazole binding and FAZA uptake. Together, these findings show that gefitinib reduces intratumoral hypoxia.

A phase I trial of high-dose palliative radiotherapy plus concurrent weekly Vinorelbine and Cisplatin in patients with locally advanced and metastatic NSCLC

The role of concurrent chemoradiotherapy (CRT) in patients with non-small-cell lung cancer (NSCLC) unsuitable for radical therapy but who require locoregional treatment has not been defined. The aims of this phase I trial were thus to develop a novel regimen of weekly chemotherapy concurrent with high-dose palliative RT (40 Gy/20 fractions) and assess its tolerability, objective and symptomatic response rates. Eligible patients had stage I–IIIB NSCLC unsuitable for radical RT or limited stage IV disease, ECOG PS⩽1 and required locoregional therapy. Treatment was RT (40 Gy/20 fractions/5 per week) and weekly Vinorelbine plus Cisplatin escalated in six planned dose levels (DLs). At 4 weeks post-RT, patients received two cycles of Cisplatin 80 mg m⁻² day 1+Vinorelbine 25 mg m⁻² days 1, 8, 15. Dose-limiting toxicities (DLTs) were defined in the CRT phase. Disease-related symptoms were assessed by the Lung Cancer Symptom Scale. In all, 24 patients accrued, stage IIIB (n=12) and IV disease (n=10). The highest administered dose was at DL 4, Vinorelbine 30 mg m⁻²+Cisplatin 20 mg m⁻² with DLTs of grade 4 neutropenia in two of three patients. No grade 3 or 4 nonhaematological toxicities were observed. The overall radiological response rate was 65% (n=23: complete response 4% and partial response 61%) and infield FDG-PET responses were seen in 89% (n=18). There was an improvement or stabilisation of symptoms and quality of life. Dose level 3, Vinorelbine 25 mg m⁻²+Cisplatin 20 mg m⁻², is recommended for further assessment. This regimen was tolerable and produced meaningful responses for patients for whom locoregional control is required, but who are unsuitable for radical CRT.

Adjuvant chemotherapy for resected non-small-cell lung cancer

Because of the high rate of distant disease recurrence, the 5-year survival of patients who have undergone complete surgical resection of localized non-small-cell lung cancer (NSCLC) is approximately 50%. Initial results from early studies of adjuvant postoperative chemotherapy reported an adverse effect of alkylating agent and older chemotherapy regimens on survival. Cisplatin-based combinations were the first to show a survival advantage. A 1995 meta-analysis of these studies suggested a 13% reduction in the hazard ratio for death (HR = 0.87), leading to a 5% survival benefit at 5 years. Still, these trials involved limited numbers of patients (N = 1,394), and the results failed to reach statistical significance (P = .08). Of the five largest subsequent randomized trials of platinum-based adjuvant therapy, three showed a significant survival advantage. Although it is impossible to determine the reasons for the differing outcomes of these studies, several key features distinguish them, and the data suggest that medically fit patients with resected stage IB or II NSCLC should be offered chemotherapy with a platinum/new drug combination.

Phase I/II study of concurrent twice-weekly paclitaxel and weekly cisplatin with radiation therapy for stage III non-small cell lung cancer

The optimal chemoradiation regimen for stage III non-small cell lung cancer (NSCLC) has not been determined. In this phase I/II study, the use of twice-weekly paclitaxel concomitant with weekly cisplatin and thoracic radiotherapy (RT) was evaluated. Patients with stage III NSCLC (without pleural effusion or cervical lymphadenopathy) were treated with thoracic RT (60 Gy in 30 fractions over 6 weeks) with concurrent weekly cisplatin 20 mg/m(2) and escalating doses of twice-weekly paclitaxel (starting dose of paclitaxel of 20 mg/m(2) increased in increments of 5 mg/m(2)) in successive cohorts of three to six patients until two or more patients experienced dose limiting toxicities (DLTs) at a particular dose level. All patients were planned to be given a further two cycles of consolidation chemotherapy consisting of paclitaxel 175 mg/m(2) and carboplatin AUC 5 after completion of RT. Twenty-five patients were enrolled in this study from two institutions. At a dose of paclitaxel 35 mg/m(2), two of four treated patients had DLTs (1 grade 3 oesophagitis and pulmonary toxicity; 1 grade 3 oesophagitis and infection). The recommended dose was therefore determined to be 30 mg/m(2) and a total of 15 patients were enrolled in an expanded cohort at this level. The overall response rate for all patients was 64% (95% CI: 43-82%). The estimated median survival was 23.6 months with an estimated 1-year and 2-year survival of 72 and 49%, respectively. Paclitaxel can be safely given twice-weekly at a dose of 30 mg/m(2) in combination with weekly cisplatin (20 mg/m(2)) and thoracic RT (60 Gy), and this regimen has significant activity in stage III NSCLC.

EGFR blockade with ZD1839 ("Iressa") potentiates the antitumor effects of single and multiple fractions of ionizing radiation in human A431 squamous cell carcinoma. Epidermal growth factor receptor

PURPOSE

Signaling pathways initiated by the epidermal growth factor receptor (EGFR) play important roles in the response to ionizing radiation. In this study the consequences of inhibiting the EGFR on the response of A431 cells (human vulvar squamous cell carcinoma cells that overexpress EGFR) to radiation, were investigated in vitro and in vivo, using the selective EGFR-tyrosine kinase inhibitor, ZD1839 ("Iressa").

METHODS AND MATERIALS

The effect of ZD1839 on proliferation, apoptosis, and clonogenic survival after radiation was determined in vitro. For in vivo studies, athymic nude mice with established subcutaneous A431 xenografts (approximately 100 mm(3)) were treated with either a single 10 Gy fraction or 4 daily 2.5 Gy fractions of radiation with or without ZD1839 (75 mg/kg/day intraperitoneally for 10 days) to determine effects on tumor growth delay.

RESULTS

Treatment of A431 cells with ZD1839 in vitro reduced proliferation, increased apoptosis, and reduced clonogenic survival after radiation. Strikingly greater than additive effects of ZD1839 in combination with radiation on tumor growth delay were observed in vivo after either a single 10 Gy fraction (enhancement ratio: 1.5) or multiple 4 x 2.5 Gy fractions (enhancement ratio: 4). ZD1839 reduced tumor vascularity, as well as levels of vascular endothelial growth factor (VEGF) protein and mRNA induced by stimulation with epidermal growth factor (EGF), suggesting a possible role of inhibition of angiogenesis in the effect.

CONCLUSIONS

Inhibiting EGFR-mediated signal transduction cascades with ZD1839 potentiates the antitumor effect of single and multiple fractions of radiation. These data provide preclinical rationale for clinical trials of EGFR inhibitors including ZD1839 in combination with radiation.

Generation and brain delivery of anti-aggregating antibodies against beta-amyloid plaques using phage display technology

Antibodies towards the N-terminal region of the beta-amyloid peptide bind to beta-amyloid fibrils, leading to their disaggregation. We generated anti-aggregating beta-amyloid antibodies using filamentous phages displaying the only four amino acids EFRH found to be the main regulatory site for beta-amyloid formation. In order to overcome the low permeability of the blood brain barrier for targeting 'anti-aggregating' mAbs to the betaA plaques in the brain, we applied antibody engineering methods to minimize the size of the mAbs while maintaining their biological activity. We found that single-chain antibodies displayed on the surface of the phage are capable of entering the central nervous system (CNS). The feasibility of these novel strategies for the production and targeting of anti-aggregating antibodies against beta-amyloid plaques to disease affected regions in the CNS may have clinical potential for treatment of Alzheimer's disease.

Applications of Positron Emission Tomography in the Development of Molecular Targeted Cancer Therapeutics

For molecular targeted cancer therapies to fulfill their promise in cancer treatment, innovative approaches are required to overcome significant obstacles that exist in the clinical development of these agents. Positron emission tomography (PET) is a functional imaging technology that allows rapid, repeated, noninvasive, in vivo assessment and quantification of many biological processes and in some cases molecular pathways targeted by these therapies. It is highly sensitive, with the capacity to detect subnanomolar concentrations of radiotracer and provides superior image resolution to conventional nuclear medicine imaging with gamma cameras. Novel PET radiotracers have been developed that allow visualisation of a variety of processes including tumour metabolism, cell proliferation, apoptosis, hypoxia and blood flow. Furthermore, specific molecular targets including cellular receptors can be identified using radiolabelled receptor ligands or specific monoclonal antibodies. Improvements in imaging technology leading to the development of small-animal PET scanners, with resolution capable of imaging commonly used mouse models of cancer, will enable PET to play an important role in preclinical proof-of-principle drug studies. Such improvements will also facilitate the validation of imaging protocols that can be readily translated to studies in humans. The greatest utility of PET in the development of molecular targeted therapeutics, however, lies in clinical studies, where PET may play a valuable role in a number of situations. These include selection of patients for therapy through noninvasive identification of the presence of specific molecular targets, pharmacokinetic studies with labelled drugs and pharmacodynamic evaluations of biological parameters to select the optimal biological dose, and assessment of response to therapies.

Single-chain antibody against the common epitope of mutant p53: isolation and intracytosolic expression in mammalian cells

The peptide epitope FRHSVV is cryptic in wild-type p53 and is exposed in many types of mutant p53 molecules isolated from various tumors. Mutant p53 marked by this epitope abrogates a tumor-suppressor function of wild-type p53 and possibly contributes to the transforming potential of other oncogenic processes. We report here the construction of a single-chain scFv antibody gene library derived from the mRNA of a mouse immunized with the epitope peptide FRHSVV which mimics the common epitope in p53 mutant protein molecules. The scFv was presented by phage display. The selected antibody gene, named ME1, was found to bind to the mutant p53 protein but not to the wild-type p53 protein. Preliminary studies show that the ME1 gene is expressed in the cytosol of mammalian cells. These findings suggest that the ME1 single-chain antibody may be useful as a tool for clarifying the role of mutant p53 in tumor transformation, especially in cells heterozygous in p53, and possibly for gene therapy of tumors.

Lack of efficacy of twice-weekly urokinase in the prevention of complications associated with Hickman catheters: a multicentre randomised comparison of urokinase versus heparin

Hickman catheters (HC) are associated with complications, in particular infection, occlusion and thrombosis. We tested the hypothesis that regular flushing of catheters with urokinase would reduce the frequency of these complications. Patients who required a double-lumen HC for (1) bone marrow or peripheral blood progenitor cell transplantation or (2) intensive combination chemotherapy for haematological malignancies were randomised to receive twice-weekly flushes of either urokinase (5000 units) or heparin (50 units). HC-survival analysis was determined by Cox regression. 100 patients were enrolled (urokinase=52; heparin=48) and treated for a mean of 8.5 weeks. No significant difference was observed in the incidence of HC-associated septicaemic events, which occurred in 8/52 in the urokinase group and 9/48 in the heparin group (actuarial incidence 20% versus 25%, P=0.50). Similarly, there was no differences in the incidence of exit site infections (urokinase=27/52 and heparin=28/48, P=0.122); HC-septic thromboses (urokinase=2/52 and heparin=4/48, P=0.34); lumen occlusion (urokinase=30/52 and heparin=30/48, P=0.681); or venous thrombosis (urokinase=8/52 and heparin=6/48, P=0.726). Overall, a high incidence of HC-related complications was seen in both groups; 40/52 in the urokinase group and 40/48 in the heparin group (actuarial incidence 80% versus 90%, P=0.367). Despite this only 18% of HC required early removal due to complications (urokinase=8, heparin=10). There was no difference in the incidence of complications in patients undergoing transplantation (n=68) compared with chemotherapy alone (n=32). Patients with haematological malignancies were more likely to have HC-related infective complications (P=0.006), and patients with solid tumours more likely to have venous thrombosis (P=0.027). The cumulative incidence of HC-related complications in this prospective study was higher than in previously reported series. Urokinase did not appear effective in reducing the frequency of these complications.

Antiaggregating antibody raised against human PrP 106-126 recognizes pathological and normal isoforms of the whole prion protein

Antibodies to the prion protein (PrP) have been critical to the neuropathological and biochemical characterization of PrP-related degenerative diseases in humans and animals. Although PrP is highly conserved evolutionarily, there is some sequence divergence among species; as a consequence, anti-PrP antibodies have a wide spectrum of reactivity when challenged with PrP from diverse species. We have produced an antibody [monoclonal antibody (mAb) 2-40] raised against a synthetic peptide corresponding to residues (106-126 of human PrP and have characterized it by epitope mapping, Western immunoblot analysis, and immunohistochemistry. The antibody recognizes not only human PrP isoforms but also pathological PrP from all species tested (i.e., sheep, hamsters, and mice). Together with the fact that it recognizes the whole PrP in both cellular and scrapie isoforms, mAb 2-40 may be helpful in studying conformational changes of the PrP, as well as establishing a possible connection between human and animal diseases.

Helix-coil transition of PrP106-126: molecular dynamic study

A set of 34 molecular dynamic (MD) simulations totaling 305 ns of simulation time of the prion protein-derived peptide PrP106-126 was performed with both explicit and implicit solvent models. The objective of these simulations is to investigate the relative stability of the alpha-helical conformation of the peptide and the mechanism for conversion from the helix to a random-coil structure. At neutral pH, the wild-type peptide was found to lose its initial helical structure very fast, within a few nanoseconds (ns) from the beginning of the simulations. The helix breaks up in the middle and then unwinds to the termini. The spontaneous transition into the random coil structure is governed by the hydrophobic interaction between His(111) and Val(122). The A117V mutation, which is linked to GSS disease, was found to destabilize the helix conformation of the peptide significantly, leading to a complete loss of helicity approximately 1 ns faster than in the wild-type. Furthermore, the A117V mutant exhibits a different mechanism for helix-coil conversion, wherein the helix begins to break up at the C-terminus and then gradually to unwind towards the N-terminus. In most simulations, the mutation was found to speed up the conversion through an additional hydrophobic interaction between Met(112) and the mutated residue Val(117), an interaction that did not exist in the wild-type peptide. Finally, the beta-sheet conformation of the wild-type peptide was found to be less stable at acidic pH due to a destabilization of the His(111)-Val(122), since at acidic pH this histidine is protonated and is unlikely to participate in hydrophobic interaction.

Immunotherapeutic strategies for prevention and treatment of Alzheimer's disease

Pathologic examination in Alzheimer's disease (AD) shows a significant correlation between beta-amyloid peptide (AbetaP) deposition and the clinical severity of dementia. Formation of beta-amyloid (Abeta) is a complex kinetic and thermodynamic process, dependent on peptide-peptide interactions that may be modulated by other proteins. We found that site-directed antibodies toward peptide EFRH sequences 3-6 of the N-terminal region of AbetaP suppress in vitro formation of Abeta and dissolve already-formed fibrillar amyloid. These so-called chaperone-like properties of monoclonal antibodies led to the development of a new immunologic approach to AD treatment. The immunization procedure, based on phages displaying the EFRH epitope as antigen, induced anti-AbetaP antibodies that recognized the whole AbetaP and exhibited antiaggregating properties similar to those of antibodies obtained by injection of Abeta fibrils. Production and performance of anti-beta-amyloid antibodies in the transgenic mouse model of AD showed that these antibodies may be delivered from the periphery to the central nervous system, preventing the formation of Abeta and dissolving already-present aggregates. Moreover, immunization with Abeta protected transgenic mice from the learning and age-related memory deficits that occur in AD. These data support the hypotheses that Abeta plays a central role in AD and that site-directed antibodies that modulate Abeta conformation may provide immunotherapy of the disease.

Zinc-mediated thermal stabilization of carboxypeptidase A

In this study we investigated the contribution of Zn ions to the catalytic and structural thermostability of carboxypeptidase A (CPA). Structural studies on CPA molecule, performed in the presence of a number of ligands, demonstrated the multiple binding models around Zn ions which may affect the enzyme functions. Zinc was reported to bind at various sites in the CPA molecule at room temperature leading to inhibition of its enzymic activity. In this study we found that binding of Zn to CPA molecule followed by exposure to 50 degrees C did not inhibit the enzymic activity but activates and protects it against heat denaturation. The stabilization effect was found to be dependent on the increasing Zn/CPA ratios. The moderate changes of CPA activity as well as the UV and fluorescence spectra analyses indicate that the main function of the newly introduced zinc atoms is structural rather than catalytical.

IgM detection via selective recognition by mannose-binding protein

Ca(2+)-dependent mannose-binding proteins (MBPs) belong to the family of animal lectins isolated from the liver and serum of rabbits, humans and rodents. They perform in vivo as defense molecules that act as opsonins by enhancing the clearance of mannose-rich pathogens and have been used in vitro for the purification of immunoglobulin M (IgM). In this study, we used MBPs as a sensitive and specific reagent for the detection of IgM due to their high specificity for mannose found only in IgM carbohydrate regions. MBP performed as a sensitive alternative to the usually used anti-IgM, where very low concentrations of IgM should be detected. IgM plays a central role in the initial response of the immune system to the invasion of foreign pathogens, as the early detection of the appearance of pathogenic IgM in biological fluids is of great significance in the diagnosis and treatment of many acute pathological cases. The development of a highly sensitive and reliable assay for the detection of low concentrations of IgM based on covalent binding on epoxy film-coated surfaces and selective recognition of IgM by MBP may be of clinical importance.

Towards Alzheimer's beta-amyloid vaccination

Beta-amyloid pathology, the main hallmark of Alzheimer's disease (AD), has been linked to its conformational status and aggregation. We recently showed that site-directed monoclonal antibodies (mAbs) towards the N-terminal region of the human beta-amyloid peptide bind to preformed beta-amyloid fibrils (Abeta), leading to disaggregation and inhibition of their neurotoxic effect. Here we report the development of a novel immunization procedure to raise effective anti-aggregating amyloid beta-protein (AbetaP) antibodies, using as antigen filamentous phages displaying the only EFRH peptide found to be the epitope of these antibodies. Due to the high antigenicity of the phage no adjuvant is required to obtain high affinity anti-aggregating IgG antibodies in animals model, that exhibit identity to human AbetaP. Such antibodies are able to sequester peripheral AbetaP, thus avoiding passage through the blood brain barrier (BBB) and, as recently shown in a transgenic mouse model, to cross the BBB and dissolve already formed beta-amyloid plaques. To our knowledge, this is the first attempt to use as a vaccine a self-anti-aggregating epitope displayed on a phage, and this may pave the way to treat abnormal accumulation-peptide diseases, such as Alzheimer's disease or other amyloidogenic diseases.

Primary large-cell non-Hodgkin's lymphoma of the testis: a retrospective analysis of patterns of failure and prognostic factors

We have analyzed 25 patients with primary testicular large-cell non-Hodgkin's lymphoma managed at our institution from 1972-1998. The median age was 69 years, with bilateral testicular involvement in 16%. The disease stage was I in 56%, II in 32%, and IV in 12%. Twenty-four patients received further therapy after orchiectomy, including chemotherapy in 18 and radiation therapy in 11 (encompassing regional nodes in 8 and the contralateral testis in 6), with 5 patients receiving both modalities. The complete remission rate was 88%, but a continuous pattern of recurrence is evident up to 10 years, when only 23% of patients are predicted to be in ongoing remission. The dominant sites of first failure were extranodal (91%), with prominent involvement of the contralateral testis and cerebral parenchyma. The 10-year overall survival rate is 32%, and the median overall survival is 4.4 years. Within the entire cohort, adverse prognostic factors for treatment failure were serum albumin < or = to 3.5 g/dL (P = 0.02), advanced age, advanced stage, and lack of anthracycline-containing chemotherapy (each P < or = to 0.3). Among patients with locoregional disease, albumin < or = to 3.5 g/dL (P = 0.08), no anthracycline-containing chemotherapy (P = 0.15), and fewer than 6 cycles of chemotherapy (P = 0.03) remained predictive. Based on this analysis, we are prospectively evaluating a treatment program for patients with testicular non-Hodgkin's large-cell lymphoma comprising (1) 6 cycles of anthracycline-based chemotherapy, (2) prophylactic radiation therapy to the contralateral testis, and (3) central nervous system prophylaxis with both intrathecal chemotherapy and systemic high-dose methotrexate.

Immunostaining of calmodulin and aluminium in Alzheimer's disease-affected brains

Previous in vitro studies have shown that Al(3+) binds to calmodulin, inducing alterations in its capability to interact with target proteins, accompanied by loss of immunological recognition by its conformational specific monoclonal antibody CAM1. In spite of the wealth of data of calmodulin action in vitro, little information is available on the possible involvement of this protein in the pathology typical of Alzheimer's disease. In the present study, we investigated calmodulin immunoreactivity in post-mortem human brains affected by Alzheimer's disease, compared with age-matched control brains. Conformational monoclonal antibodies raised against Ca(2+)-calmodulin, namely CAM1 and CAM4, were used in this study for the characterization of calmodulin. Calmodulin immunorecognition by monoclonal antibody CAM1 was found to be lost in cortical tissue sample from brains affected by Alzheimer's disease. This finding leads to the hypothesis of a new, possibly inactive, conformation of the molecule during the disease. On the other hand, CAM4 immunoreactivity was decreased in neurons of brains affected by Alzheimer's disease. Anti-Al(3+) monoclonal antibodies revealed instead more marked aluminium immunoreactivity in the affected brains compared to normal ones. The loss of CAM1 immunoreactivity and the occurrence of large amounts of aluminium suggest an alteration of the active conformation of calmodulin in disease-affected brains. These alterations could be involved in the development of Alzheimer's disease pathology.

Generation of auto-antibodies towards Alzheimer's disease vaccination

We developed a novel procedure to evoke anti-aggregating beta-amyloid (Abeta) antibodies, using filamentous phages displaying only four amino acids EFRH of the beta-amyloid peptide (AbetaP). This epitope was found to be the main regulatory site for fibril formation. For the first time, effective auto-antibodies have been obtained in guinea-pigs, which exhibit human identity in the AbetaP. Immunization through a phage-carrying epitope was found to be long-lasting, and no toxic effect caused by autoimmune response was detected in the challenged animal sections. These antibodies performed similarly to site-directed monoclonal antibodies and to antibodies raised against fibrillar Abeta in disaggregation of plaques, and may serve as the basis for developing an anti-Abeta vaccine.

Thyroglobulin messenger ribonucleic acid levels in the peripheral blood of children with benign and malignant thyroid disease

Reverse transcriptase-PCR has identified thyroglobulin mRNA (Tg mRNA) in peripheral blood of normal adults and adults with thyroid cancer. However, no children were studied. The primary objective of this study was to determine whether whole blood Tg mRNA levels differ between benign and malignant thyroid disease in children. The secondary goals were to determine whether whole blood Tg mRNA levels vary with age or pubertal development among children with thyroid disease. Whole blood Tg mRNA levels were determined in 38 children (29 girls, nine boys; median age, 14.5 y; range, 4.8-20.4 y) with benign and malignant thyroid disease and correlated with diagnosis, age, pubertal status, thyroid size, and serum levels of free thyroxine, TSH, and Tg protein. Tg mRNA levels ranged from 3.3 to 104 pg Eq/microg total thyroid RNA (mean, 28 +/- 20.2 pg Eq/microg total thyroid RNA) and were similar in benign and malignant disorders (p = 0.67). However, in children with previously treated papillary thyroid cancer, Tg mRNA levels directly correlated with total body (131)I uptake (p = 0.026) and serum Tg protein (p = 0.037). There was no difference between boys and girls, and no change with pubertal maturation. In children with benign thyroid disease, Tg mRNA levels correlated with serum TSH (p = 0.031), but not with diagnosis, age, Tanner stage, or thyroid size. We conclude that Tg mRNA levels are similar in children with benign and malignant thyroid disease and unchanged by age or pubertal status, but correlated with tumor burden in previously treated papillary thyroid cancer.

NIH symposium summary: organ preservation therapies for squamous cancers of the head and neck

This symposium, sponsored by the NIH Office of Rare Diseases, the National Cancer Institute, the National Institute of Deafness and Other Communication Disorders, and the National Institute of Dental and Craniofacial Diseases, reviewed the current status of organ preservation therapies for head and neck cancers, as well as promising newer approaches for therapy and for toxicity amelioration.

Immunomodulation of the human prion peptide 106-126 aggregation

Site-directed monoclonal antibodies (mAbs) may interact with their antigens, leading to stabilization, refolding, and suppression of aggregation. In the following study, we show that mAbs raised against the peptide 106-126 of human prion protein (PrP 106-126) modulate the conformational changes occurring in the peptide exposed to aggregation conditions. MAbs 3-11 and 2-40 prevent PrP 106-126's fibrillar aggregation, disaggregates already formed aggregates, and inhibits the peptide's neurotoxic effect on the PC12 cells system, while mAb 3F4 has no protective effect. We suggest that there are key positions within the PrP 106-126 molecule where unfolding is initiated and their locking with specific antibodies may maintain the prion peptide native structure, reverse the aggregated peptide conformation, and lead to rearrangements involved in the essential feature of prion diseases.

VIP and peptides related to activity-dependent neurotrophic factor protect PC12 cells against oxidative stress

Oxidative stress is a common associative mechanism that is part of the pathogenesis of many neurodegenerative diseases. Vasoactive intestinal peptide (VIP) is a principal neuropeptide associated with normal development and aging. We have previously reported that VIP induced the secretion of proteins from glial cells, including the novel survival-promoter: activity-dependent neurotrophic factor (ADNF). ADNF-9, a nine amino acid peptide derived from ADNF, protects neurons from death caused by various toxins. In the present study, we examined the neuroprotective effect of VIP against oxidative stress in a pheochromocytoma cell line (PC12). In addition, a lipophilic derivative of VIP, Stearyl-Nle17-VIP (SNV), and two femtomolar-acting peptides: ADNF-9 and a 70% homologous peptide to ADNF-9, NAP were tested as well. PC12 cells were treated with 100 microM H2O2 for 24 h resulting in a reduction in cell survival to 35-50% as compared to controls. Addition of VIP or SNV prior and during the exposure to100 microM H2O2 increased cell survival to 80-90% of control values. Culture treatment with ADNF-9 or NAP in the presence of 100 microM H2O2 increased cell survival to 75-80% of control values. Messenger RNA expression analysis revealed that incubation with VIP resulted in a twofold increase in VIP mRNA, whereas NAP treatment did not cause any change in VIP expression, implicating different mechanisms of action. Furthermore, addition of an ADNF-9 antibody prevented the ability of VIP to protect against oxidative stress, suggesting that VIP protection is partially mediated via an ADNF-like protein.

Immunization against Alzheimer's beta -amyloid plaques via EFRH phage administration

The epitope EFRH, corresponding to amino acids 3-6 within the human beta-amyloid peptide (AbetaP), acts as a regulatory site controlling both the formation and disaggregation process of the beta-amyloid fibrils (Abeta). Locking of this epitope by highly specific antibodies affects the dynamics of the entire AbetaP molecule, preventing self-aggregation as well as enabling resolubilization of already formed aggregates. Production of such antibodies by repeated injections of toxic human Abeta fibrils into transgenic mice suggests the feasibility of vaccination against Alzheimer's disease. Here, we report the development of an immunization procedure for the production of effective anti-aggregating beta-amyloid antibodies based on filamentous phages displaying the EFRH peptide as specific and nontoxic antigen. Effective autoimmune antibodies were obtained by EFRH phage administration in guinea pigs, which exhibit AbetaP identical to the human AbetaP region. Moreover, because of the high antigenicity of the phage, no adjuvant is required to obtain high affinity anti-aggregating IgG antibodies after a short immunization period of 3 weeks. Availability of such antibodies opens up possibilities for the development of an efficient and long-lasting vaccination for the prevention and treatment of Alzheimer's disease.

Vaccination for the prevention and treatment of Alzheimer's disease

In vitro studies showed that beta-amyloid peptide neurotoxicity correlates with the formation of fibrillar beta-amyloid and the variation in neurotoxic potency is related to the extent of peptide aggregation. Many efforts are being focused on the development of potent and selective inhibitors of amyloid formation in order to reduce the extent of their deposition and related neurotoxic effects. In our laboratory we are pioneering the idea that site-directed monoclonal antibodies (MAbs) can solubilize synthetic beta-amyloid aggregates. Production and performance of such antibodies by repeated injections of toxic human beta-amyloid fibrils into transgenic mice suggests the feasibility of vaccination against Alzheimer's disease (AD). Here we report the development of a novel immunization procedure for the production of effective antiaggregating beta-amyloid antibodies. The antigen is built from filamentous phages displaying the only four amino acids EFRH located at positions 3-6 of the beta-amyloid peptide found to be the main regulatory site of amyloid formation. Autoimmune antibodies are obtained by EFRH phage administration in guinea pigs, which exhibit human identity in the beta-amyloid peptide region. Availability of such antibodies opens up possibilities for the development of an efficient and long-lasting immunization procedure for the treatment of AD.

Modulation of Alzheimer's beta-amyloid neurotoxicity by site-directed single-chain antibody

A single-chain antibody was constructed from variable regions of heavy and light genes of the parental anti-beta-amyloid peptide IgM 508 antibody. This antibody exhibits anti-aggregating properties, leading to disaggregation of Alzheimer beta-amyloid (betaA) fibrils and prevents its toxic effect on cultured PC-12 cells. Sequencing of the small antibody, namely 508 (Fv), revealed that the V(L) domain contained a cysteine residue in the complementary determining region (CDR)3 (residue 96) which affects its solubility and stability. The cysteine codon was replaced using SOE PCR, and one of the mutants obtained, namely 508F(Fv) (containing phenylalanine instead of cysteine), showed an increased storage stability and higher affinity compared to the wild type. Antibody 508F(Fv) prevents the neurotoxicity of betaA (90% cell viability) and disrupts the fibril structure of beta-amyloid (62% decrease in ThT fluorescence). The ability of antibody 508F(Fv) to dissolve already-formed betaA fibrils makes it a good candidate for intracellular expression and modulation of APP processing as the first step towards the production of therapeutic protection molecules for Alzheimer's disease treatment.

Interactions of calmodulin with metal ions and with its target proteins revealed by conformation-sensitive monoclonal antibodies

Two monoclonal antibodies (mAbs) raised against bovine calmodulin (CaM), CAM1 and CAM4, enable one to monitor conformational changes that occur in the molecule. The interaction of CAM1 with CaM depends on the Ca2+ occupancy of its Ca(2+)-binding sites. CAM4, in contrast, interacts with CaM in a Ca(2+)-independent manner, interacting with both holoCaM and EGTA-treated CaM to a similar extent. Their interaction with various CaMs, CaM tryptic fragments and chemically modified CaM, as well as molecular graphics, led to identification of the CAM1 and CAM4 epitopes on the C- and N-terminal lobes of CAM respectively. The two mAbs were used as macromolecular probes to detect conformational changes occurring in the CaM molecule upon binding of metal ions and target proteins and peptides. MAb CAM1 successfully detected changes associated with Al3+ binding even in the presence of Ca2+, indicating that Al3+ and Ca2+ ions may bind to the protein simultaneously, leading to a new conformation of the molecule. MAbs CAM1 and CAM4 were used to follow the interactions of CaM with its target peptides and proteins. Complexes with melittin, mastoparan, calcineurin and phosphodiesterase showed different immunological properties on an immuno-enzyme electrode, indicating unique structural properties for each complex.

Intravenous extension of lung carcinoma to the left atrium: demonstration by positron emission tomography with CT correlation

Intravenous extension of lung carcinoma is rare. A right upper lobe bronchogenic carcinoma with unusually elongated intravenous extension to the left atrium was first visualized with positron emission tomography (PET) and then confirmed with dynamic CT. The PET appearance of intravascular tumour spread is striking, and presents only a short differential diagnosis.

Chemoembolization of hepatocellular carcinoma with cisplatin, doxorubicin, mitomycin-C, ethiodol, and polyvinyl alcohol: prospective evaluation of response and survival in a U.S. population

PURPOSE

To evaluate response and survival after hepatic chemoembolization with cisplatin, doxorubicin, mitomycin-C, Ethiodol, and polyvinyl alcohol in a U.S. population of patients with hepatocellular carcinoma.

MATERIALS AND METHODS

Thirty-eight consecutive patients were treated: 35% stage I, 62% stage II, 3% stage III. Fifty-one percent had cirrhosis. Chemoembolization was performed at approximately monthly intervals for one to seven sessions (mean, 2.2). Pretreatment and posttreatment cross-sectional imaging and alpha-fetoprotein (AFP) levels were obtained prospectively 1 month after treatment and then every 3 months. Thirty-day response was calculated by means of the the World Health Organization/Eastern Cooperative Oncology Group criteria.

RESULTS

One patient was lost to follow-up. In seven patients, lesions became resectable after chemoembolization. Among 13 evaluable patients with initially elevated AFP level, 70% had a partial biologic response (>50% decrease in AFP), 15% had a minor response (25-50% decrease), and the remaining 15% remained stable. Among 25 patients evaluable for morphologic response, 36% had a partial response, 32% had a minor response, and 32% remained stable. No patients had progression of disease while receiving therapy. The cumulative survival was 60% at 1 year, 41% at 2 years, and 16% at 3 years. Two patients developed progressive hepatic failure. Thirty-day mortality was 3% (one patient).

CONCLUSION

These results compare favorably to published response and survival data for chemoembolization of advanced hepatocellular carcinoma from Asia and Europe.

Quantitative reverse transcription-PCR measurement of thyroglobulin mRNA in peripheral blood of healthy subjects

BACKGROUND

Thyroglobulin mRNA can be detected qualitatively in the peripheral blood of patients with metastatic thyroid cancer, thyroid cancer patients with residual thyroid bed uptake, and individuals with no known thyroid disease with intact thyroid glands by use of a lengthy, highly sensitive extraction technique. To improve and broaden the clinical usefulness of this assay, we developed a quantitative reverse transcription (RT)-PCR assay for thyroglobulin mRNA, using RNA recovered from whole blood with a simplified extraction technique.

METHODS

Whole blood was drawn from 32 healthy subjects in standard EDTA blood collection tubes. Total RNA was extracted from whole blood, using the PUREscript RNA Isolation Kit. RT-PCR using intron-spanning primers was used to quantitatively amplify thyroglobulin mRNA, using the ABI PRISM 7700 Sequence Detection System with a fluorescent-labeled, thyroglobulin-specific oligonucleotide probe. Thyroid RNA calibration curves were created using total RNA recovered from a single nondiseased thyroid gland.

RESULTS

Qualitative RT-PCR demonstrated the presence of thyroglobulin mRNA in the whole blood sample of each healthy subject. The mean concentration of thyroglobulin mRNA detected in these subjects was 433 +/- 69 ng of total thyroid RNA per liter of whole blood (range, 26-1502 ng/L). Overall assay imprecision (CV) was 24% for five samples analyzed 10 times each in separate analytical runs on different days.

CONCLUSIONS

Thyroglobulin mRNA can be accurately detected and quantified in peripheral blood from healthy subjects. This new quantitative technique may improve the clinical utility of circulating thyroglobulin mRNA detection in patients with thyroid disease.

High affinity binding of monoclonal antibodies to the sequential epitope EFRH of beta-amyloid peptide is essential for modulation of fibrillar aggregation

Monoclonal antibodies raised against the N-terminal of Alzheimer's beta-amyloid peptide (betaAP) were found to modulate its fibrillar aggregation. While mAbs 6C6 and 10D5 inhibit the formation of beta-amyloid fibrils, trigger disaggregation and reversal to its non-toxic form, mAb 2H3 is devoid of these properties. MAb 2H3 binds the sequence DAEFRHD, corresponding to position 1-7 of the betaAP with high affinity (2 x 10(-9) M) similar to its binding with the whole betaAP. The EFRH peptide strongly inhibits binding of mAbs 6C6 and 10D5 to betaAP, whereas it inhibits weakly the interaction of 2H3 with betaAP. Low affinity binding of mAb 2H3 to EFRH might explain its failure in prevention of beta-amyloid formation.

Immuno-detection of aluminium and aluminium induced conformational changes in calmodulin--implications in Alzheimer's disease

Binding of calcium to calmodulin (CAM) induces specific structural rearrangements in the whole protein molecule. Ca2+ organizes and stabilizes the four-domains structure of calmodulin in a helical, active conformation that can bind to its target proteins; the central helix remaining flexible is an essential condition for their bio-recognition. The conformation of calmodulin, and its efficacy to interact with target proteins, is profoundly altered when bound to metal ions other than calcium. As recently reported, the local structural changes of CaM, which occur upon aluminium binding, lead to the impairment of protein flexibility and to the loss of its ability to interact with several other proteins, which may decrease or inhibit the regulatory character of calmodulin. In this study we followed conformational changes occurring in the calmodulin molecule after aluminium binding using highly specific monoclonal antibodies (mAbs) able to differentiate between the conformational states of calmodulin, as well as mAbs which recognize aluminium free or bound to proteins. Under the same experimental conditions, mAb CAM-1, a Ca2+ conformation sensitive antibody raised against calmodulin, fails to recognize the calmodulin-aluminium complex, despite the presence of Ca2+, while the anti-Al antibodies show a maximal binding pattern towards their antigen. These data suggest that Al3+ ions bind to calmodulin in the presence of Ca2+ ions, leading to an inactive, reversible conformation, instead of its physiological active form. Alteration of the conformation of calmodulin imposed by Al binding may have possible implications in the neurotoxicity mechanism related to Alzheimer's disease.