High correspondence between EGFR mutations in tissue and in circulating DNA form non-small-cell lung cancer (NSCLC) patients (p) with poor performance status (PS)

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Background: We evaluated the correspondence between EGFR mutations in NSCLC tissue and matched serum DNA and the value of EGFR mutations as a serological marker. Methods: 121 Spanish stage IV NSCLC p received customized first- or second-line erlotinib monotherapy based on the presence of EGFR mutations in the tumor tissue. Serum genomic DNA was obtained from all p prior to erlotinib administration. EGFR exon 19 deletions were studied by length analysis of fluorescently labeled PCR products and the exon 21 L858R mutation by a PCR Taqman assay. Results: The EGFR mutation status in the serum was consistent with that in the tumor tissue of 82/121 p (68%) and of 15/16 p (93.8%) with PS 2 had mutations. Overall, 64.3% of p had an exon 19 deletion and 35.7% had L858R. 78% of mutations were found in females (P=0.01) and 77.6% in never-smokers (P=0.07). Response rate was 88% in p with mutations only in the tumor and 87% in p with mutations in tumor and serum. Complete responses were observed in 20% of p with mutations in tumor and serum vs 4% of p with mutations only in tumor (P=0.09). With a median follow-up of 6.8 months (m) (range, 1.2–17.6), time to progression (TTP) and median survival have not been reached. A trend to better outcome was seen in p without serum EGFR mutations. TTP was longer for p with EGFR exon 19 deletions (not reached) than for p with L858R (7.7 m) (P=0.02). TTP for p with PS 2 with exon 19 deletions was not reached, while it was 2.7 m for p with L858R (P=0.17). Conclusions: EGFR mutations in serum could be a non-invasive source of information on the genotype of the original tumor cells and could be a useful tool to predict p response to erlotinib, especially in p with poor PS.

No significant financial relationships to disclose.

The place of targeted therapies in the management of non-small cell bronchial carcinoma. Molecular markers as predictors of tumor response and survival in lung cancer

This review highlights the numerous molecular biology findings in the field of lung cancer with potential therapeutic impact in both the near and distant future. Abundant pre-clinical and clinical data indicate that BRCA1 mRNA expression is a differential modulator of chemotherapy sensitivity. Low levels predict cisplatin sensitivity and antimicrotubule drug resistance, and the opposite occurs with high levels. The main core of recent research has centered on epidermal growth factor receptor (EGFR) mutations and gene copy numbers. For the first time, EGFR mutations have been shown to predict dramatic responses in metastatic lung adenocarcinomas, with a threefold increase in time to progression and survival in patients receiving EGFR tyrosine-kinase inhibitors. Evidence has also been accumulated on the crosstalk between estrogen and EGFR receptor pathways, paving the way for clinical trials of EGFR tyrosine-kinase inhibitors plus aromatase inhibitors. Understanding the relevance of these findings can help to change the clinical practice in oncology towards customizing chemotherapy and targeted therapies, leading to improvement both in survival and in cost-effectiveness.

Clinical outcome of gemcitabine (gem)/cisplatin (cis)- vs docetaxel (doc)/cis-treated stage IV non-small cell lung cancer (NSCLC) patients (p) according to X-ray repair cross-complementing group 3 (XRCC3) polymorphism and age

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Background: Significant interaction between XRCC1 genotype and age has been reported, with younger subjects having a greater risk of developing lung cancer. Carriers of XRCC3 241 MetMet have higher levels of DNA adducts, leading us to hypothesize that they would be more chemosensitive, especially younger patients. Methods: Real-time PCR assay was used to determine XRCC3 genotype from DNA isolated from baseline blood samples of 878 stage IV NSCLC p (162 treated with gem/cis; 716 with doc/cis). Median age, 60; 266 p (30%) <55; 239 p (39%) 55–66; 273 p (31%) >66. Adenocarcinoma: 459 p (53%). Homozygous variant XRCC3 241 MetMet was found in 124 p (14%), with the same frequency in each of the three age groups. Results: After a median follow-up of 7.6 months (m) (95% CI, 1–47 m), overall median survival (MS) was 9.5 m (95% CI, 8.8–10.2 m), with no differences between the 2 regimens. In all p with XRCC3 241 MetMet, MS was 12.9 m for p treated with gem/cis and 8.4 m for p treated with doc/cis (P = 0.06) (hazard ratio at 2 y = 0.23). In p with XRCC3 241 MetMet <55 y, MS was not reached for p treated with gem/cis and 9.2 m for p treated with doc/cis (P = 0.02), which translated into a 60% difference in survival at 2 y. This difference diminished in p with XRCC3 241 MetMet 55–66 y (MS 12.9 m with gem/cis, 6.9 m with doc/cis [P = 0.09]; 28% difference in survival at 2 y) and disappeared in p >66 y (MS 5.8 m with gem/cis, 7.8 m with doc/cis [P = 0.55]. For the other XRCC3 241 genotypes (ThrThr and ThrMet), no differences in MS were found either overall or broken down by age. Conclusions: XRCC3 241 MetMet is both an easily assessable and robust predictive marker for survival in younger gem/cis-treated NSCLC p. The survival benefit dwindles with increasing age, possibly related to the enhanced DNA repair capacity of older p.

No significant financial relationships to disclose.

Epidermal growth factor receptor activating mutations in Spanish gefitinib-treated non-small-cell lung cancer patients

BACKGROUND

North American and Japanese non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) activation via tyrosine kinase (TK) mutations respond dramatically to gefitinib treatment. To date, however, the frequency and effect of EGFR TK mutations have not been examined in European patients.

PATIENTS AND METHODS

Eighty-three Spanish advanced NSCLC patients who had progressed after chemotherapy, were treated with compassionate use of gefitinib. Patients were selected on the basis of available tumor tissue. Tumor genomic DNA was retrieved from paraffin-embedded tissue obtained by laser capture microdissection. EGFR mutations in exons 19 and 21 were examined by direct sequencing.

RESULTS

EGFR mutations were found in 10 of 83 (12%) of patients. All mutations were found in adenocarcinomas, more frequently in females (P=0.007) and non-smokers (P=0.01). Response was observed in 60% of patients with mutations and 8.8% of patients with wild-type EGFR (P=0.001). Time to progression for patients with mutations was 12.3 months, compared with 3.6 months for patients with wild-type EGFR (P=0.002). Median survival was 13 months for patients with mutations and 4.9 months for those with wild-type EGFR (P=0.02).

CONCLUSIONS

EGFR TK mutational analysis is a novel predictive test for selecting lung adenocarcinoma patients for targeted therapy with EGFR TK inhibitors.

The regulation of alpha chemokines during HIV-1 infection and leukocyte activation: relevance for HIV-1-associated dementia

Cellular immunity against human immunodeficiency virus type 1 (HIV-1)-infected brain macrophages serves to prevent productive viral replication in the nervous system. Inevitably, during advanced disease, this antiretroviral response breaks down. This could occur through virus-induced dysregulation of lymphocyte trafficking. Thus, we studied the production of non-ELR-containing alpha-chemokines and their receptor (CXCR3) expression in relevant virus target cells. Macrophages, lymphocytes, and astrocytes secreted alpha-chemokines after HIV-1 infection and/or immune activation. Lymphocyte CXCR3-mediated chemotactic responses were operative. In all, alpha-chemokine-mediated T cell migration continued after HIV-1 infection and the neuroinflammatory events operative during productive viral replication in brain.

Design and synthesis of irreversible depsipeptidyl human rhinovirus 3C protease inhibitors

Novel tripeptidyl C-terminal Michael acceptors with an ester replacement of the P(2)-P(3) amide bond were investigated as irreversible inhibitors of the human rhinovirus (HRV) 3C protease (3CP). When screened against HRV serotype-14 the best compound was shown to have very good 3CP inhibition (k(obs)/[I]=270,000M(-1)s(-1)) and potent in vitro antiviral activity (EC(50)=7.0nM).

Analysis of transition from long-term nonprogressive to progressive infection identifies sequences that may attenuate HIV type 1

Long-term nonprogressive human immunodeficiency virus type 1 (HIV-1) infection and its transition to progressive infection presents an opportunity to identify the molecular determinants of HIV-1 attenuation and pathogenesis. We studied an individual who underwent a transition from long-term nonprogressive to rapidly progressive infection. Because HIV-1 RNA genomes in plasma represent replicating virus, we developed a technique to clone full-length HIV-1 RNA genomes from plasma and used this technique to obtain clones from this individual before and during the transition. Most clones assayed were infectious, demonstrating that the RNA genomes encoded viable virus. Analysis of 20 complete HIV-1 RNA genomic sequences revealed one major difference between sequences found during the two phases of infection. During the nonprogressive phase, the predominant sequences had a large deletion in an Sp1-binding site and adjacent promoter in the U3 part of the long terminal repeat (LTR); when the infection became progressive, all viruses had intact Sp1 and promoter sequences and were derived from a minor species present earlier. Analysis of 184 clones of the LTR region obtained at five time points spanning a 7-year period confirmed this switch. In an in vitro assay, the deletion downregulated LTR-driven transcription of a reporter gene. In addition, analysis of cytotoxic T lymphocyte (CTL) epitopes predicted from the complete viral RNA genomes revealed multiple potential escape mutants that accumulated by the time of progression. These studies suggest that during the nonprogressive phase, the Sp1 enhancer-promoter deletion is likely to have played a role in decreasing replication, thereby attenuating HIV-1. The accumulation of CTL escape mutants suggests that a breakdown in immunologic surveillance may have allowed proliferation of intact virus, thus leading to rapid disease progression. These data reveal the viral and immune interactions characterizing a transition from long-term nonprogressive to rapidly progressive infection.

Distinct behavioral and neuropathological abnormalities in transgenic mouse models of HD and DRPLA

Huntington's disease (HD) and Dentatorubral and pallidoluysian atrophy (DRPLA) are autosomal dominant, neurodegenerative disorders caused by the expansion of polyglutamine tracts in their respective proteins, huntingtin and atrophin-1. We have previously generated mouse models of these disorders, using transgenes expressed via the prion protein promoter. Here, we report the first direct comparison of abnormalities in these models. The HD mice show abbreviated lifespans (4-6 months), hypoactivity, and mild impairment of motor skills. The DRPLA mice show severe tremors, are hyperactive, and are profoundly uncoordinated. Neuropathological analyses reveal that the distribution of diffuse nuclear immunolabeling and neuronal intranuclear inclusions (NII's), in the CNS of both models, was remarkably similar. Cytoplasmic aggregates of huntingtin were the major distinguishing neuropathological feature of the HD mice; mutant atrophin-1 accumulated/aggregated only in the nucleus. We suggest that the distinct behavioral and neuropathological phenotypes in these mice reflect differences in the way these mutant proteins perturb neuronal function.

A frameshift mutation in NOD2 associated with susceptibility to Crohn's disease

Crohn's disease is a chronic inflammatory disorder of the gastrointestinal tract, which is thought to result from the effect of environmental factors in a genetically predisposed host. A gene location in the pericentromeric region of chromosome 16, IBD1, that contributes to susceptibility to Crohn's disease has been established through multiple linkage studies, but the specific gene(s) has not been identified. NOD2, a gene that encodes a protein with homology to plant disease resistance gene products is located in the peak region of linkage on chromosome 16 (ref. 7). Here we show, by using the transmission disequilibium test and case-control analysis, that a frameshift mutation caused by a cytosine insertion, 3020insC, which is expected to encode a truncated NOD2 protein, is associated with Crohn's disease. Wild-type NOD2 activates nuclear factor NF-kappaB, making it responsive to bacterial lipopolysaccharides; however, this induction was deficient in mutant NOD2. These results implicate NOD2 in susceptibility to Crohn's disease, and suggest a link between an innate immune response to bacterial components and development of disease.

Preparation of monoclonal antibodies to murine platelet glycoprotein IIb/IIIa (alphaIIbbeta3) and other proteins from hamster-mouse interspecies hybridomas

To obtain mouse-specific monoclonal antibodies (mAbs) against platelet proteins, an Armenian hamster was immunized with washed mouse platelets. Immune splenocytes were then fused with a nonsecreting murine myeloma cell line, and the resulting heterohybridomas were screened for antibody production utilizing an ELISA in which the target antigen was mouse platelets adsorbed onto microtiter plates in the presence of thrombin. Secondary screening assays included ELISA tests using murine fibrinogen or platelets from beta3-integrin knockout mice, flow cytometry, immunoblotting, immunoprecipitation, and a functional assay to identify antibodies that inhibit platelet-fibrinogen interactions. Hybridoma cells producing hamster mAbs against murine glycoprotein (GP) IIb/IIIa, fibrinogen, CD9, and other platelet integrins were identified. Two hybridomas (1B5 and 9C2) producing antibodies that react with the GPIIb/IIIa complex in immunoprecipitation analysis were subcloned twice. Functional analyses by means of aggregation and adhesion assays revealed that 1B5 completely inhibits platelet-fibrinogen interactions, whereas 9C2 does not affect platelet aggregation or platelet adhesion.