A cloud on the horizon-a survey into the use of electronic vaping devices for recreational drug and new psychoactive substance (NPS) administration

BACKGROUND

There is limited published scientific data on vaping recreational drugs other than cannabis. A recent review suggested that 15% of people vaping cannabis have also vaped a synthetic cannabinoid receptor agonist (SCRA) and identified over 300 Internet reports of e-liquid manufacture of recreational drugs and/or new psychoactive substances (NPS).

AIM

To determine the prevalence of use of electronic vaping devices for recreational drug and NPS delivery in the UK.

DESIGN

A voluntary online survey using a convenience sample of UK adult participants (aged 16 years old and over) identified by a market research company.

METHODS

Data was collected regarding demographics, smoking history, electronic vaping device history and recreational drug/NPS use and route of administration.

RESULTS

There were 2501 respondents. The mean (±SD) age was 46.2 ± 16.8 years old. The commonest lifetime recreational drug used was Cannabis (818, 32.7%). The majority of respondents had smoked (1545, 61.8%) with 731 (29.2%) being current smokers. The most commonly used SCRA product was 'Spice Gold' (173, 6.9%) and SCRA compound was ADB-CHMICA (48, 1.9%). 861 (34.4%) had used an electronic vaping device; 340 (13.6%) having used them for recreational drug administration; 236 (9.4%) reporting current use. The commonest lifetime recreational drug to be vaped was cannabis (155, 65.7%), with electronic cigarettes (230, 48.2%) being the commonest reported route of SCRA compound administration.

CONCLUSION

9.4% of respondents currently use electronic vaping devices for recreational drug administration with 6.2% reporting lifetime cannabis vaping use. Further larger scale studies are required to help inform the appropriate treatment and primary prevention strategies.

Corrigendum: Clinical effectiveness and cost-effectiveness of first-line chemotherapy for adult patients with locally advanced or metastatic non-small cell lung cancer: a systematic review and economic evaluation

Table 96 has been removed as it includes incorrect hazard ratios caused by a reversal of the hazard ratio calculations. However, this does not impact on any of the clinical or economic results reported.

Clinical effectiveness and cost-effectiveness of first-line chemotherapy for adult patients with locally advanced or metastatic non-small cell lung cancer: a systematic review and economic evaluation

BACKGROUND

The National Institute for Health and Care Excellence (NICE) has issued multiple guidance for the first-line management of patients with lung cancer and recommends different combinations of chemotherapy treatments. This review provides a synthesis of clinical effectiveness and cost-effectiveness evidence supporting current guidance.

OBJECTIVES

To evaluate the clinical effectiveness and cost-effectiveness of first-line chemotherapy currently licensed in Europe and recommended by NICE, for adult patients with locally advanced or metastatic non-small cell lung cancer (NSCLC).

DATA SOURCES

Three electronic databases (MEDLINE, EMBASE and The Cochrane Library) were searched from 2001 to August 2010.

REVIEW METHODS

Trials that compared first-line chemotherapy currently licensed in Europe and recommended by NICE in chemotherapy-naive adult patients with locally advanced or metastatic NSCLC were included. Data on key outcomes including, but not limited to, overall survival (OS), progression-free survival (PFS) and adverse events (AEs) were extracted. For the assessment of cost-effectiveness, outcomes included incremental cost per quality-adjusted life-year (QALY) gained. Analyses were performed for three NSCLC subpopulations: patients with predominantly squamous disease, patients with predominantly non-squamous disease and patients with epidermal growth factor receptor (EGFR) mutation-positive (M+) status. Meta-analysis and mixed-treatment comparison methodology were conducted where appropriate.

RESULTS

Twenty-three trials involving > 11,000 patients in total met the inclusion criteria. The quality of the trials was poor. In the case of patients with squamous disease, there were no statistically significant differences in OS between treatment regimes. The mixed-treatment comparison demonstrated that, in patients with non-squamous disease, pemetrexed (Alimta®, Eli Lilly and Company; PEM) + platinum (PLAT) increases OS statistically significantly compared with gemcitabine (Gemzar®, Eli Lilly and Company; GEM) + PLAT [hazard ratio (HR) = 0.85; 95% confidence interval (CI) 0.74 to 0.98] and that paclitaxel (Abraxane®, Celgene Corporation; PAX) + PLAT increases OS statistically significantly compared with docetaxel (Taxotere®, Sanofi-aventis; DOC) + PLAT (HR = 0.79, 95% CI 0.66 to 0.93). None of the comparisons found any statistically significant differences in OS among patients with EGFR M+ status. Direct meta-analysis showed a statistically significant improvement in PFS with gefitinib (Iressa®, AstraZeneca; GEF) compared with DOC + PLAT and PAX + PLAT (HR = 0.49; 95% CI 0.33 to 0.73; and HR = 0.38; 95% CI 0.24 to 0.60, respectively). No papers related to UK decision-making were identified. A de novo economic model was developed. Using list prices (British National Formulary), cisplatin (CIS) doublets are preferable to carboplatin doublets, but this is reversed if electronic market information tool prices are used, in which case drug administration costs then become more important than drug acquisition costs. For patients with both squamous and non-squamous disease, moving from low to moderate willingness-to-pay thresholds, the preferred drugs are PAX → GEM → DOC. However, in patients with non-squamous disease, PEM + CIS resulted in increased OS and would be considered cost-effective up to £35,000 per QALY gained. For patients with EGFR M+, use of GEF compared with PAX or DOC yields very high incremental cost-effectiveness ratios. Vinorelbine (Navelbine®, Pierre Fabre Pharmaceutical Inc.) was not shown to be cost-effective in any comparison.

LIMITATIONS

Poor trial quality and a lack of evidence for all drug comparisons complicated and limited the data analysis. Outcomes and adverse effects are not consistently combined across the trials. Few trials reported quality-of-life data despite their relevance to patients and clinicians.

CONCLUSIONS

The results of this comprehensive review are unique to NSCLC and will assist clinicians to make decisions regarding the treatment of patients with advanced NSCLC. The design of future lung cancer trials needs to reflect the influence of factors such as histology, genetics and the new prognostic biomarkers that are currently being identified. In addition, trials will need to be adequately powered so as to be able to test for statistically significant clinical effectiveness differences within patient populations. New initiatives are in place to record detailed information on the precise chemotherapy (and targeted chemotherapy) regimens being used, together with data on age, cell type, stage of disease and performance status, allowing for very detailed observational audits of management and outcomes at a population level. It would be useful if these initiatives could be expanded to include the collection of health economics data.

FUNDING

The National Institute for Health Research Health Technology Assessment.

Lapatinib and trastuzumab in combination with an aromatase inhibitor for the first-line treatment of metastatic hormone receptor-positive breast cancer which over-expresses human epidermal growth factor 2 (HER2): a systematic review and economic analysis

BACKGROUND

Breast cancer is the uncontrolled, abnormal growth of malignant breast tissue affecting predominantly women. Metastatic breast cancer (mBC) is an advanced stage of the disease when the disease has spread beyond the original organ. Hormone receptor status and human epidermal growth factor 2 (HER2) status are two predictive factors that are taken into consideration when estimating the prognosis of patients with breast cancer.

OBJECTIVES

To review the clinical effectiveness and cost-effectiveness evidence base for lapatinib (LAP) in combination with an aromatase inhibitor (AI) and trastuzumab (TRA) in combination with an AI for the first-line treatment of patients who have hormone receptor-positive (HR+)/human epidermal growth factor 2-positive (HER2+) mBC.

DATA SOURCES

Relevant electronic databases and websites, including MEDLINE, EMBASE and the Cochrane Library, were searched until May 2010. Further data were derived from the manufacturers' submissions for LAP + AI and TRA + AI.

REVIEW METHODS

A systematic review of the clinical effectiveness and cost-effectiveness of LAP + AI and TRA + AI was undertaken. As it was deemed inappropriate to compare LAP + AI with TRA + AI, two separate assessments of cost-effectiveness versus AIs alone were undertaken.

RESULTS

Three trials were included in the systematic review [the patient populations of the efficacy and safety of lapatinib combined with letrozole (EGF30008) trial, the efficacy and safety of trastuzumab combined with anastrozole (TAnDEM) trial and the efficacy and safety of letrozole combined with trastuzumab (eLEcTRA) trial]. As a result of differences in the exclusion criteria and because one trial was halted prematurely, comparisons across trials were believed to be inappropriate and meta-analysis was not possible. Individually, however, the findings from the trials all suggest that LAP + AI or TRA + AI results in improved progression-free survival and/or time to progression when compared with AIs alone. The trials do not show a statistically significant benefit in terms of overall survival. Two separate economic analyses were conducted based on the completed trials; neither LAP + AI nor TRA + AI was found to be cost-effective when compared with AI monotherapy.

LIMITATIONS

Because of differences in the EGF30008 and the TAnDEM trials, the Assessment Group believes the indirect comparisons analyses conducted by the manufacturers are inappropriate and, for the same reason, chooses not to compare LAP + AI with TRA + AI in an economic evaluation.

CONCLUSIONS

LAP + AI and TRA + AI appear to be clinically more effective than AI monotherapy, but neither is cost-effective compared with AIs alone. It was not possible to compare LAP + AI with TRA + AI. Future research should include research into treating mBC in the HR+/HER2+ population who are not TRA (or LAP) naive and into comparing the clinical effectiveness of AIs as monotherapy in patients with HER2+ and human epidermal growth factor 2-negative breast cancer.

FUNDING

The National Institute for Health Research Technology Assessment programme.

Clopidogrel and modified-release dipyridamole for the prevention of occlusive vascular events (review of Technology Appraisal No. 90): a systematic review and economic analysis

BACKGROUND

Occlusive vascular events such as myocardial infarction (MI), ischaemic stroke and transient ischaemic attack (TIA) are the result of a reduction in blood flow associated with an artery becoming narrow or blocked through atherosclerosis and atherothrombosis. Peripheral arterial disease is the result of narrowing of the arteries that supply blood to the muscles and other tissues, usually in the lower extremities. The primary objective in the treatment of all patients with a history of occlusive vascular events and peripheral arterial disease is to prevent the occurrence of new occlusive vascular events.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of clopidogrel and modified-release dipyridamole (MRD) alone or with aspirin (ASA) compared with ASA (and each other where appropriate) in the prevention of occlusive vascular events in patients with a history of MI, ischaemic stroke/TIA or established peripheral arterial disease. To consider the clinical effectiveness and cost-effectiveness of clopidogrel in patients with multivascular disease. This review is an update of the evidence base for the National Institute for Health and Clinical Excellence (NICE) guidance Technology Appraisal No. 90 (TA90) entitled Clopidogrel and modified-release dipyridamole for the prevention of occlusive vascular events (2005).

DATA SOURCES

Four electronic databases (EMBASE, MEDLINE, Web of Science and The Cochrane Library) were searched for randomised controlled trials (RCTs) and economic evaluations. Submissions to NICE by the manufacturers of the interventions were also considered.

REVIEW METHODS

A systematic review of clinical effectiveness and cost-effectiveness was conducted. To manage heterogeneity between trials, indirect analysis (using a mixed-treatment methodology) was performed on selected clinical outcomes. A new economic model was developed to assess incremental costs per life-year gained [quality-adjusted life-years (QALYs)].

RESULTS

For evidence of clinical effectiveness, four RCTs were identified: CAPRIE (Clopidogrel versus Aspirin in Patients at Risk of Ischaemic Events), ESPRIT (European/Australasian Stroke Prevention in Reversible Ischaemia Trial), PRoFESS (Prevention Regimen For Effectively avoiding Second Strokes) and ESPS-2 (Second European Stroke Prevention Study). In CAPRIE (patients with MI, ischaemic stroke or peripheral arterial disease), statistically significant outcomes in favour of clopidogrel were noted for the primary outcome (first occurrence of ischaemic stroke, MI or vascular death) compared with ASA [relative risk reduction 8.7%; 95% confidence interval (CI) 0.3% to 16.5%; p = 0.043]. In ESPRIT (patients with ischaemic stroke/TIA) for the primary outcome (first occurrence of death from all vascular causes, non-fatal stroke, non-fatal MI or major bleeding complication), the risk of event occurrence was statistically significantly lower in the MRD + ASA arm than in the ASA arm [hazard ratio (HR) 0.80; 95% CI 0.66 to 0.98], with no statistically significant difference in bleeding events between the two arms. In PRoFESS (patients with ischaemic stroke) the rate of recurrent stroke of any type (primary outcome) was similar in the MRD + ASA and clopidogrel groups, and the null hypothesis (that MRD + ASA was inferior to clopidogrel) could not be rejected. In ESPS-2 (patients with ischaemic stroke/TIA), on the primary outcome of stroke, statistically significant differences in favour of MRD + ASA were observed compared with ASA and MRD alone (relative risk 0.76; 95% CI 0.63 to 0.93). The outcomes addressed in the mixed-treatment comparisons (limited by the available data) for the ischaemic stroke/TIA population confirmed the results of the direct comparisons. The 11 economic evaluations included in the review of cost-effectiveness indicated that for patients with previous peripheral arterial disease, ischaemic stroke or MI, clopidogrel is cost-effective compared with ASA, and for patients with previous ischaemic stroke/TIA, treatment with MRD + ASA is cost-effective compared with any other treatment in patients in the secondary prevention of occlusive vascular events. The relevance of the review was limited as the economic evaluations were not based on the most current clinical data. Cost-effectiveness results generated from the Assessment Group's de novo economic model suggested that the most cost-effective approach for patients with ischaemic stroke/TIA is clopidogrel followed by MRD + ASA then ASA. For patients with MI, the most cost-effective approach is ASA followed by clopidogrel. For patients with established peripheral arterial disease, the most cost-effective approach is clopidogrel followed by ASA. For patients with multivascular disease, clopidogrel followed by ASA is the most cost-effective approach. Incremental cost-effectiveness ratios (ICERs) were also calculated for patients who are intolerant to ASA. Assuming that the branded price for clopidogrel is used and TA90 guidance is not applied, all of the ICERs range between £2189 and £13,558 per QALY gained. Probabilistic sensitivity analyses were fully consistent with these findings.

CONCLUSIONS

The evidence suggests that the most cost-effective treatment for patients with ischaemic stroke/TIA is clopidogrel followed by MRD + ASA followed by ASA; for patients with MI, ASA followed by clopidogrel; and for patients with established peripheral arterial disease or multivascular disease, clopidogrel followed by ASA.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Hematopoietic-specific lentiviral vectors circumvent cellular toxicity due to ectopic expression of Wiskott-Aldrich syndrome protein

Efficient and safe gene modification of hematopoietic stem cells is a requirement for gene therapy of primary immunodeficiencies such as Wiskott-Aldrich syndrome. However, deregulated expression or ectopic expression in the progeny of transduced nonhematopoietic progenitor cells may lead to unwanted toxicity. We therefore analyzed the effect of ectopic expression of Wiskott-Aldrich syndrome protein (WASp) and the potential benefits of hematopoietic-specific lentiviral vectors (driven by the WAS proximal promoter). Overexpression of WASp by constitutive lentiviral vectors is highly toxic in nonhematopoietic cells because it causes dramatic changes in actin localization and polymerization that result in decreased cell viability, as evidenced by a significant growth disadvantage of WASp-overexpressing nonhematopoietic cells and increased cell death. These toxic effects do not affect cells of hematopoietic origin because, remarkably, we found that WASp cannot be readily overexpressed in T cells, even after multiple vector integrations per cell. The adverse cellular effects found after transduction of nonhematopoietic cells with constitutive lentiviral vectors are overcome by the use of transcriptionally targeted lentiviral vectors expressing WASp, which, at the same time, are efficient tools for gene therapy of WAS as demonstrated by their ability to reconstitute cellular defects from WASp-deficient mouse and human cells. We therefore postulate that transcriptionally regulated lentiviral vectors represent a safer and efficient alternative for the development of clinical protocols of WAS gene therapy.

Lentiviral vectors transcriptionally targeted to hematopoietic cells by WASP gene proximal promoter sequences

The development of vectors that express a therapeutic transgene efficiently and specifically in hematopoietic cells (HCs) is an important goal for gene therapy of hematological disorders. In order to achieve this, we used a 500 bp fragment from the proximal WASP gene promoter to drive the expression of the WASP cDNA in the context of a self-inactivating lentiviral vector. Single-round transduction of WASp-deficient herpesvirus saimiri (HVS)-immortalized cells as well as primary allospecific T cells from Wiskott-Aldrich syndrome (WAS) patients with this vector (WW) resulted in expression levels similar to those of control cells. Non-HCs were transduced with similar efficiency, but the levels of WASp were 135-350 times lower than those achieved in HCs. Additionally, transduction of WASp-deficient cells with WW conferred a selective growth advantage in vitro. Therefore, lentiviral vectors incorporating proximal promoter sequences from the WASP gene confer hematopoietic-specific, and physiological protein expression.

Restoration of podosomes and chemotaxis in Wiskott-Aldrich syndrome macrophages following induced expression of WASp

We used a direct-viewing (Dunn) chemotaxis chamber to analyse the chemotactic responses of human normal and Wiskott-Aldrich syndrome (WAS) macrophages to the cytokine colony stimulating factor-1 (CSF-1). In five patients with classic WAS, where specialised adhesion complexes called podosomes are absent, chemotaxis of macrophages was abolished. The deficient chemotactic responses of WAS macrophages following cytokine stimulation could be correlated with abnormalities in cell polarisation and actin organisation. In a series of cell microinjection studies we found that normal chemotactic responses were restored in WASp macrophages transfected with a full-length human WAS construct. Expression of exogenous WAS protein (WASp) in these cells also restored normal polarised cell morphology and the ability to form podosomes.

Application of a high-throughput antibody-based assay for identification of the granule-bound starch synthase Wx-B1b allele in Australian wheat lines

An enzyme-linked immunosorbent assay (ELISA) for the discrimination of Wx-B1a and Wx-B1b genotypes at the granule-bound starch synthase I (GBSSI) or waxy locus of hexaploid wheat (Triticum aestivum L.) was adapted to a high-throughput, 96-well microtitre plate format. This test is applicable to the direct analysis of starch, flour, or crushed grain and requires less than 1 grain to perform. Several hundred samples may be routinely analysed in one day. The assay was validated using quantitative trait locus (QTL) analysis of a doubled haploid mapping population of the cross Cranbrook (Wx-B1a)/Halberd (Wx-B1b). This demonstrated that the assay unambiguously identified 153 of 161 lines analysed, with a highly significant QTL (LRS value 270) accounting for 83% of ELISA variation, at the Wx-B1 locus on chromosome 4AL. In addition, measurement of total GBSSI variation using a non-isoform-specific GBSSI detection monoclonal antibody also gave a significant QTL (LRS of 84, accounting for 42% of ELISA variation) at the Wx-B1 locus. Application of the assay to crude flour extracts of 8 grains for each of 1093 progeny from 4 crosses segregating at the Wx-B1 locus permitted the unambiguous scoring of lines as pure Wx-B1a or pure Wx-B1b. The scoring by ELISA was strongly related to the flour swelling volume of the lines, thus demonstrating the utility of this high-throughput screening method for the faster, more efficient development of Australian noodle wheats.

Acidic fibroblast growth factor is progressively increased in the development of oesophageal glandular dysplasia and adenocarcinoma

AIMS

To determine by immunohistochemistry and amplification of cDNA the relationship between fibroblast growth factor (FGF) expression and progressive changes in Barrett's oesophagus associated with oesophageal adenocarcinoma (OA). The FGFs are potent mitogens that possess angiogenic properties and the capability to regulate growth and differentiation of various cell types. They have also been implicated in the development and progression of numerous solid tumours, including some carcinomas of the aerodigestive tract, such as nasopharyngeal carcinoma and pancreatic adenocarcinoma.

MATERIAL AND RESULTS

We studied the expression of the two prototypic FGFs, acidic FGF (FGF-1) and basic FGF (FGF-2), in OA and OA precursor lesions, including intestinal metaplasia (IM), low-grade dysplasia (LGD) and high-grade dysplasia (HGD). Fresh tissue from 10 OAs and four associated HGDs was available for the determination of FGF-1 and FGF-2 mRNA expression accomplished by the PCR amplification of cDNA. Using immunohistochemistry, we studied the expression of the FGF-1 and FGF-2 proteins in archival, paraffin-embedded tissue that was available from 17 oesophageal resection specimens that included OAs and OA precursor lesions. As compared to gastric fundic mucosal controls, OAs and HGDs showed significantly enhanced expression of FGF-1 mRNA and protein. IMs and LGDs showed significantly lesser degrees of FGF-1 immunoreactivity that were not increased over controls. In contrast, both the overall percentage of FGF-2-reactive OAs and the overall FGF-2 protein expression, assessed using an immunoreactivity score, are comparable to FGF-2 expression in controls.

CONCLUSIONS

It appears that FGF-2 is ubiquitously expressed in OA and in normal oesophageal and gastric mucosa while significant FGF-1 expression is essentially restricted to HGD and OA. Our data also suggest that FGF-1 is sequentially upregulated in the progression from metaplasia to dysplasia and adenocarcinoma.

Phenotypic characteristics of Obsessive-Compulsive Disorder ascertained in adulthood

Over the past decade, the increased awareness and knowledge of Obsessive-Compulsive Disorder (OCD) has allowed the in-depth study of its phenotypic characteristics. The largest studies to date have described the symptom and syndrome characteristics of treatment-seeking patients. While usefully homogeneous with regard to their current state, the clinical characteristics of patients seeking treatment may only partially represent the OCD population. We report findings from 100 self-selected volunteers at various stages of their OCD illness who were participating in a genetic study. Many similarities with past reports were found, including high rates of mood disorder, significantly more mood disorder in females as compared with males, and increased social impairment among males despite an equal amount of time in episodes of disorder. On the other hand, mean age of onset in this nontreatment seeking population was younger. Lifetime rates of obsessions and compulsions in this population were substantially higher than previous reports, suggesting that the content of obsessions and compulsions shifted over time, and evolved into a lifetime repertoire. Furthermore, a separate analysis of the age of clinically significant O-C symptom onset without impairment revealed that males and females did not differ, suggesting that previous reports of earlier onset age in males may actually reflect earlier onset of impairment. Future genetic studies may benefit from the analysis of both significant O-C symptom onset, as well as the onset of full-syndromal OCD. These findings may suggest phenotypic characteristics that define homogeneous subgroups of patients with OCD.

Loss of heterozygosity and homozygous deletion of the tpr locus in human gastric cancer

BACKGROUND

Despite being one of the world's most common neoplasias, there is little information on the molecular events that lead to gastric cancer. Molecular studies have shown that inactivation of tumor suppressor genes by mutation and/or allelic loss is an important genetic alteration in the multistep process of tumorigenesis.

METHODS

In an attempt to identify a putative tumor suppressor gene involved in the carcinogenesis of gastric cancer, we performed Southern blot analysis using the tpr probe for 44 patients with gastric cancer, using tumor tissue and normal tissue from the same specimen.

RESULTS

Of the 44 samples, 7 (16%) were informative, heterozygous cases for the tpr probe. Three of the informative cases showed a loss of heterozygosity and 3 cases showed homozygous deletion for the tpr probe (6 of 7; 85%).

CONCLUSIONS

These findings suggest that tpr gene plays a role in gastric tumorigenesis, and this may be due to a tumor suppressor effect for the tpr gene.

Amplification of HER-2/neu gene in human gastric adenocarcinomas: correlation with primary site

Adenocarcinomas of the proximal stomach including the gastroesophageal junction are extremely virulent cancers which are increasing rapidly in incidence. Stage-for-stage proximal gastric cancers have a worse prognosis than do tumors of the body or antrum of the stomach. To further explore biological differences based on site, we studied 80 patients with locally advanced primary tumours of the proximal (n = 40) and distal stomach (n = 40) for amplification of the HER-2/neu proto-oncogene. None of 40 patients with proximal lesions had overexpression of HER-2/neu, whereas four of 40 (10%) distal adenocarcinomas had a 16-24-fold gene amplification (P = 0.04). In the adenocarcinomas from two patients, gene rearrangements were found in addition to amplification. HER-2/neu gene product p185 over-expression was found only in the amplified cases. All four patients with distal tumors and amplification had rapid progression of disease (median survival: 4.3 months). While it is unclear why HER-2/neu amplification is seen only in distal tumors, these data further support the hypothesis that biological differences between proximal and distal lesions are present. As is the case for other tumours, HER-2/neu amplification is associated with a poor prognosis for the individual patient.

Characterization of cell lines established from human gastric-esophageal adenocarcinomas. Biologic phenotype and invasion potential

BACKGROUND

Gastric carcinoma is one of the most common malignancies worldwide, with an overall survival of about 10%. Improvement in therapy awaits better understanding of the biologic behavior of this tumor. Establishment of cell lines permits detailed analysis of the biology of gastric cancer. The authors report on the establishment and characterization of five cell lines arising from primary proximal gastric and distal esophageal adenocarcinomas.

METHODS

Cultures of epithelial cells from adenocarcinomas of the proximal stomach or adenocarcinoma of the lower esophagus were established. Gastric cancer cell lines were analyzed for doubling times, anchorage-independent growth, tumorigenic and metastatic potential in nu/nu mice, expression of keratin proteins by indirect immunofluorescence, invasive potential in a Boyden Chamber, and growth factor production by reverse transcription of mRNA in cDNA and subsequent amplification by the polymerase chain reaction.

RESULTS

Five cell lines were derived from primary gastric adenocarcinomas of the proximal stomach and from Barrett esophagus. All five cell lines were tumorigenic but not metastatic in vivo. None were capable of anchorage independent growth in vitro. Two lines were highly invasive in the Boyden chamber assay, whereas two lines were minimally or noninvasive. All five cell lines expressed RNA transcripts specific for the growth factors TGF beta 1, TGF beta 2, TGF beta 3, TGF alpha, and platelet-derived growth factor A, whereas subsets of cell lines expressed transcripts for aFGF, bFGF, FGF-5, Hst, and platelet-derived growth factor B.

CONCLUSIONS

Five cell lines derived from primary gastric-esophageal adenocarcinomas were established in tissue culture. These cell lines show differences in morphologic features, growth potential, and invasiveness. These newly established gastric cancer cell lines should prove useful for a wide range of studies attempting to decipher the biology of proximal gastric adenocarcinoma.

Translation and mRNA decay

Degradation of messenger RNA from the lactose operon (lac mRNA) was measured during the inhibition of protein synthesis by chloramphenicol (CM) or of translation-initiation by kasugamycin (KAS). With increasing CM concentration mRNA decay becomes slower, but there is no direct proportionality between rates of chemical decay and polypeptide synthesis. During exponential growth lac mRNA is cleaved endonucleolytically (Blundell and Kennell, 1974). At a CM concentration which completely inhibits all polypeptide synthesis this cleavage is blocked. In contrast, if only the initiation of translation is blocked by addition of KAS, the cleavage rate as well as the rate of chemical decay are increased significantly without delay. These faster rates do not result from immediate degradation of the lengthening stretch of ribosome-free proximal message, since the full-length size is present and the same discrete message sizes are generated during inhibition. These results suggest that neither ribosomes nor translation play an active role in the degradative process. Rather, targets can be protected by the proximity of a ribosome, and without nearly ribosomes the probability of cleavage becomes very high. During normal growth there is a certain probability that any message is in such a vulnerable state, and the fraction of vulnerable molecules determines the inactivation rate of that species.