Estimating the effects of preventive and weight-management interventions on the prevalence of childhood obesity in England: a modelling study

BACKGROUND

The effects of the systematic delivery of treatments for obesity are unknown. We aimed to estimate the potential effects on the prevalence of childhood obesity of systematically offering preventive and treatment interventions to eligible children in England, based on weight or health status.

METHODS

For this modelling study, we developed a cross-sectional simulation model of the child and young adult population in England using data from multiple years of the Health Survey of England conducted between Jan 1, 2010, and Dec 31, 2019. Individuals were assessed for eligibility via age, BMI, and medical complications. Weight status was defined based on clinical criteria used by the UK National Institute of Health and Care Excellence. Published systematic reviews were used to estimate effect sizes for treatments, uptake, and completion for each weight-management tier. We used all available evidence, including evidence from studies that showed an unfavourable effect. We estimated the effects of two systematic approaches: a staged approach, in which children and young people were simultaneously given the most intensive treatment for which they were eligible, and a stepped approach, in which each management tier was applied sequentially, with additive effects. The primary outcomes were estimated prevalence of clinical obesity, defined as a BMI ≥98th centile on the UK90 growth chart, and difference in comparison with the estimated baseline prevalence.

FINDINGS

18 080 children and young people were included in the analytical sample. Baseline prevalence of clinical obesity was estimated to be 11·2% (95% CI 10·5 to 11·8) for children and young people aged 2-18 years. In modelling, we estimated absolute decreases in the prevalence of obesity of 0·9% (95% CI 0·1 to 1·8) for universal, preventive interventions; 0·2% (0·1 to 0·4) for interventions within a primary-care setting; 1·0% (0·1 to 2·1) for community and lifestyle interventions; 0·2% (0·0 to 0·4) for pharmaceutical interventions; and 0·4% (0·1 to 0·7) for surgical interventions. Staged care was estimated to result in an absolute decrease in the prevalence of obesity of 1·3% (-0·3 to 2·4) and stepped care was estimated to lead to an absolute decrease of 2·4% (0·1 to 4·8).

INTERPRETATION

Although individual effect sizes for prevention and treatment interventions were small, when delivered at scale across England, these interventions have the potential to meaningfully contribute to reducing the prevalence of childhood obesity.

FUNDING

UK National Institute for Health and Care Research.

Advertising and Young People's Critical Reasoning Abilities: Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

Young people are exposed to an abundance of advertising for unhealthy products (eg, unhealthy foods, tobacco, alcohol). Because of their developing cognition, children may not be able to understand the intent of advertising. However, advertising restrictions often assume that adolescents have critical reasoning capacity and can resist the effects of advertising. This review seeks to assess whether the evidence supports this assumption.

METHODS

Ten databases were searched in December 2020. Inclusion criteria were participants aged 6 to 17 years, any advertising exposure, objectively measured understanding or attitudinal outcome, a comparison, control, and between-group comparison. This study included all languages and excluded studies published pre-2010. Two reviewers independently extracted data and assessed study quality.

RESULTS

Thirty-eight articles were included. Meta-analysis of 9 studies with attitudinal outcomes indicated that unhealthy product advertising generated more positive brand or product attitudes compared with neutral or no advertising control in all ages. There were significant effects for digital and nondigital advertising formats. We found greater understanding did not protect against the impact of advertising on brand or product attitudes. Limitations include the inability to meta-analyze the impact of advertising on understanding or the influence of age.

CONCLUSIONS

Evidence shows that the attitudes of young people were influenced by advertising. Critical reasoning abilities did not appear to be fully developed during adolescence and not found to be protective against the impact of advertising. Policymakers should ensure regulations to restrict marketing of unhealthy commodities protects adolescents as well as younger children.

The impact on dietary outcomes of licensed and brand equity characters in marketing unhealthy foods to children: A systematic review and meta-analysis

Licensed and brand equity characters are used to target children in the marketing of products high in fat, salt, and sugar (HFSS), but the impact of characters on dietary outcomes is unclear. The primary aim of this review was to quantify the impact of both licensed and brand equity characters on children's dietary outcomes given that existing regulations often differentiates between these character types. We systematically searched eight interdisciplinary databases and included studies from 2009 onwards until August 2021, including all countries and languages. Participants were children under 16 years, exposure was marketing for HFSS product with a character, and the outcomes were dietary consumption, preference, or purchasing behaviors of HFSS products. Data allowed for meta-analysis of taste preferences. A total of 16 articles (including 20 studies) met the inclusion criteria, of which five were included in the meta-analysis. Under experimental conditions, the use of characters on HFSS packaging compared with HFSS packaging with no character was found to result in significantly higher taste preference for HFSS products (standardized mean difference on a 5-point scale 0.273; p < 0.001). Narrative findings supported this, with studies reporting impact of both character types on product preferences including food liking and snack choice. There was limited evidence on the impact on purchase behaviors and consumption. These findings are supportive of policies that limit the exposure of HFSS food marketing using characters to children.

Modeling the impact of calorie-reduction interventions on population prevalence and inequalities in childhood obesity in the Southampton Women's Survey

BACKGROUND

In the United Kingdom, rates of childhood obesity are high and inequalities in obesity have widened in recent years. Children with obesity face heightened risks of living with obesity as adults and suffering from associated morbidities. Addressing population prevalence and inequalities in childhood obesity is a key priority for public health policymakers in the United Kingdom and elsewhere. Where randomized controlled trials are not possible, potential policy actions can be simulated using causal modeling techniques.

OBJECTIVES

Using data from the Southampton Women's Survey (SWS), a cohort with high quality dietary and lifestyle data, the potential impact of policy-relevant calorie-reduction interventions on population prevalence and inequalities of childhood obesity was investigated.

METHODS

Predicted probabilities of obesity (using UK90 cut-offs) at age 6-7 years were estimated from logistic marginal structural models adjusting for observed calorie consumption at age 3 years (using food diaries) and confounding. A series of policy-relevant intervention scenarios were modeled to simulate reductions in energy intake (differing in effectiveness, the targeting mechanisms, and level of uptake).

RESULTS

At age 6-7 years, 8.3% of children were living with obesity, after accounting for observed energy intake and confounding. A universal intervention to lower median energy intake to the estimated average requirement (a 13% decrease), with an uptake of 75%, reduced obesity prevalence by 1% but relative and absolute inequalities remained broadly unchanged.

CONCLUSIONS

Simulated interventions substantially reduced population prevalence of obesity, which may be useful in informing policymakers.

Obesity prevention in the early years: A mapping study of national policies in England from a behavioural science perspective

Background

Evidence indicates that early life is critical for determining future obesity risk. A sharper policy focus on pregnancy and early childhood could help improve obesity prevention efforts. This study aimed to systematically identify and categorise policy levers used in England with potential to influence early life course (pregnancy, 0–5 years) and identify how these interface with energy balance behaviours. The objective is to identify gaps and where further policy actions could most effectively focus.

Methods

A behavioural science approach was taken using the Capability-Opportunity-Motivation-Behaviour (COM-B) model and Behaviour Change Wheel (BCW) framework. The key determinants of energy balance in the early years were identified from the Foresight Systems Map. Policy actions were scoped systematically from available literature, including any health or non-health policies which could impact on energy balance behaviours. Foresight variables and policy actions were considered in terms of COM-B and the BCW to determine approaches likely to be effective for obesity prevention and treatment. Existing policies were overlaid across the map of key risk factors to identify gaps in obesity prevention and treatment provision.

Results

A wide range of policy actions were identified (n = 115) to address obesity-relevant risk factors. These were most commonly educational or guidelines relating to environmental restructuring (i.e. changing the physical or social context). Scope for strengthening policies relating to the food system (e.g. the market price of food) and psychological factors contributing to obesity were identified. Policies acted via all aspects of the COM-B model, but there was scope for improving policies to increase capability through skills acquisition and both reflective and automatic motivation.

Conclusions

There is substantial policy activity to address early years obesity but much is focused on education. Scope exists to strengthen actions relating to upstream policies which act on food systems and those targeting psychological factors contributing to obesity risk.

Front of pack nutritional labelling schemes: a systematic review and meta-analysis of recent evidence relating to objectively measured consumption and purchasing

BACKGROUND

Front of pack labelling (FOPL) provides visible nutritional information and appears to influence knowledge and reformulation. However, a recent Cochrane review found limited and inconsistent evidence for behaviour change. The present review aimed to examine studies published subsequent the Cochrane review, focusing on prepackaged foods, examining the impact of FOPL on purchasing and consumption.

METHODS

Controlled experimental/intervention and interrupted time series (ITS) studies were included, with no age/geography restrictions. Exposures were FOPL with objectively measured consumption/purchasing outcomes. Thirteen databases were searched (January 2017 to April 2019) and forward citation searching was undertaken on the included studies. Purchasing data from experimental studies were meta-analysed. Two series of meta-analyses were undertaken; combined FOPL versus no-FOPL and specific FOPL scheme versus no-FOPL. Outcomes were sugar (g 100 g^-1 ), calories (kcal 100 g^-1 ), saturated fat (g 100 g^-1 ) and sodium (mg 100 g^-1 ).

RESULTS

We identified 14 studies, reporting consumption (experimental; n = 3) and purchasing (n = 8, experimental; n = 3, ITS). Meta-analysis of experimental studies showed sugar and sodium content of purchases was lower for combined FOPL versus no-FOPL (-0.40 g sugar 100 g^-1 , P < 0.01; -24.482 mg sodium 100 g^-1 , P = 0.012), with a trend for lower energy and saturated fat (-2.03 kcal 100 g^-1 , P = 0.08; -0.154 g saturated fat 100 g^-1 , P = 0.091). For specific FOPL, products purchased by 'high in' FOPL groups had lower sugar (-0.67 g sugar 100 g^-1 , P ≤ 0.01), calories (-4.43 kcal 100 g^-1 , P < 0.05), sodium (-33.78 mg 100 g^-1 , P = 0.01) versus no-FOPL; Multiple Traffic Light had lower sodium (-34.94 mg 100 g^-1 , P < 0.01) versus no-FOPL. Findings regarding consumption were limited and inconsistent. FOPL resulted in healthier purchasing in ITS studies.

CONCLUSIONS

This review provides evidence from experimental and 'real-life' studies indicating that FOPL encourages healthier food purchasing. PROSPERO CRD42019135743.

School closure and management practices during coronavirus outbreaks including COVID-19: a rapid systematic review

In response to the coronavirus disease 2019 (COVID-19) pandemic, 107 countries had implemented national school closures by March 18, 2020. It is unknown whether school measures are effective in coronavirus outbreaks (eg, due to severe acute respiratory syndrome [SARS], Middle East respiratory syndrome, or COVID-19). We undertook a systematic review by searching three electronic databases to identify what is known about the effectiveness of school closures and other school social distancing practices during coronavirus outbreaks. We included 16 of 616 identified articles. School closures were deployed rapidly across mainland China and Hong Kong for COVID-19. However, there are no data on the relative contribution of school closures to transmission control. Data from the SARS outbreak in mainland China, Hong Kong, and Singapore suggest that school closures did not contribute to the control of the epidemic. Modelling studies of SARS produced conflicting results. Recent modelling studies of COVID-19 predict that school closures alone would prevent only 2-4% of deaths, much less than other social distancing interventions. Policy makers need to be aware of the equivocal evidence when considering school closures for COVID-19, and that combinations of social distancing measures should be considered. Other less disruptive social distancing interventions in schools require further consideration if restrictive social distancing policies are implemented for long periods.

School closure and management practices during coronavirus outbreaks including COVID-19: a rapid systematic review

In response to the coronavirus disease 2019 (COVID-19) pandemic, 107 countries had implemented national school closures by March 18, 2020. It is unknown whether school measures are effective in coronavirus outbreaks (eg, due to severe acute respiratory syndrome [SARS], Middle East respiratory syndrome, or COVID-19). We undertook a systematic review by searching three electronic databases to identify what is known about the effectiveness of school closures and other school social distancing practices during coronavirus outbreaks. We included 16 of 616 identified articles. School closures were deployed rapidly across mainland China and Hong Kong for COVID-19. However, there are no data on the relative contribution of school closures to transmission control. Data from the SARS outbreak in mainland China, Hong Kong, and Singapore suggest that school closures did not contribute to the control of the epidemic. Modelling studies of SARS produced conflicting results. Recent modelling studies of COVID-19 predict that school closures alone would prevent only 2-4% of deaths, much less than other social distancing interventions. Policy makers need to be aware of the equivocal evidence when considering school closures for COVID-19, and that combinations of social distancing measures should be considered. Other less disruptive social distancing interventions in schools require further consideration if restrictive social distancing policies are implemented for long periods.

The effect of screen advertising on children's dietary intake: A systematic review and meta-analysis

Evidence indicates that screen advertising for unhealthy food results in significant increases in dietary intake among children. This review was undertaken with the main aim of estimating the quantitative effect of screen advertising in experimental and nonexperimental conditions on children's dietary intake. Systematic searches were undertaken of interdisciplinary databases. Studies from 1980 to April 2018, all geography and languages, were included; participants were children and adolescents aged between 2 and 18 years; the intervention was screen advertising; and the outcome was dietary intake. Meta-analyses were conducted for measured and nonmeasured outcomes. Food advertising was found to increase dietary intake among children (age range 2-14, mean 8.8 years) in experimental conditions for television (TV) advertising and advergames. Meta-analysis revealed that children exposed to food advertising on TV (11 studies) and advergames (five studies) respectively consumed an average 60.0 kcal (95% confidence interval [CI], 3.1-116.9) and 53.2 kcal (95% CI, 31.5-74.9) more than children exposed to nonfood advertising. There was also an effect by body mass index (BMI). Findings from nonexperimental studies revealed that exposure to TV food advertising was positively associated with and predictive of dietary intake in children. Short-term exposure to unhealthy food advertising on TV and advergames increases immediate calorie consumption in children.

Abstract P6-21-03: Phase I trial of intratumoral (IT) administration of a NIS-expressing derivative manufactured from a genetically engineered strain of measles virus (MV)

Background: The live attenuated non-pathogenic Edmonston MV vaccine strain has advantages as an oncolytic platform given its tumor specificity, potent bystander effect, and ability to be engineered and retargeted. MV-NIS expresses the human thyroidal sodium-iodide symporter (NIS) and is selectively oncolytic, entering tumor cells through CD46 (overexpressed on many cancers, including breast cancer of all subtypes) and Nectin-4. NIS expression in MV-NIS infected cells permits noninvasive monitoring of virus spread by SPECT-CT imaging of Tc-99m pertechnetate or I-123 uptake.

Methods: NCT01846091 is a standard 3+3 phase I trial of a single IT administration of MV-NIS in pts with recurrent/metastatic squamous cell carcinoma of the head and neck (SCCHN) or metastatic breast cancer (MBC). Primary objectives are (a) safety and tolerability and (b) maximally tolerated single dose. The secondary clinical objective is to preliminarily assess antitumor efficacy at and away from the MV injection site. Key eligibility criteria were: absence of standard therapy with life prolonging intent; at least one lesion &gt;1 cm amenable to percutaneous injection; and no impending visceral crisis. MV-NIS was administered on D1 with mandatory SPECT-CT at baseline (BL) and on D3&D8; repeat SPECT-CT on D15&D21 if the prior result was positive; mandatory tumor biopsies on D3&D21; optional tumor biopsies on D8&D15; assessments for viremia and viral shedding at BL and on D3,D8,D15,D21; and standard imaging for restaging at BL,D21,W6,W12.

Results: Accrual completed with 12 evaluable pts (6 SCCHN and 6 MBC) at 3 dose levels (108, 3x108, 109 TCID50). The MBC group included 5 HR+/HER2- pts and 1 pt with mixed HR+/HER2- and HR+/HER2+ disease. 5 pts had evidence of disease progression prior to study participation. No dose limiting toxicities were observed among the MBC pts; AEs possibly related to MV-NIS in this group were gr2 fatigue, gr1 flu-like illness, gr2 lymphopenia (all n=1). No SCCHN responses were observed. Best response for the MBC pts was: stable disease (SD) &gt;6 wks, n=4; clinical response, n=1; progression, n=1. One MBC pt with SD for 12 wks had positive SPECT/CT imaging at and away from the injection site on D3&D8 and was the only pt seronegative for measles IgG antibodies prior to MV-NIS exposure. The MBC pt who responded after initial MV-NIS exposure was the only pt with low viral RNA in blood (D3); she received additional doses at W9&W13 without toxicity through an expanded access protocol exemption and had disease progression by W19. No viral shedding was detected from mouth rinse or urine in any pt. MV was detected in tumor samples from all pts treated at the highest dose level. Additional blood and tissue analyses are in progress.

Conclusion: These results demonstrate the safety of IT MV-NIS administration, provide early evidence of biologic activity in MBC, and support the possibility of viral replication in tumors remote from the IT injection site. A MV strain encoding the immunomodulatory neutrophil activating protein transgene has been constructed (MV-s-NAP) with preclinical evidence of improved antitumor activity and immunogenicity. The phase I MV-s-NAP trial will start recruitment in Fall 2018.

Citation Format: Liu MC, Peng K-W, Federspiel MJ, Russell SJ, Brunton BA, Zhou Y, Packiriswamy N, Hubbard JM, Loprinzi CL, Peethambaram PP, Ruddy KJ, Allred JB, Galanis E, Okuno SH. Phase I trial of intratumoral (IT) administration of a NIS-expressing derivative manufactured from a genetically engineered strain of measles virus (MV) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-21-03.

PIWIs, piRNAs and Retrotransposons: Complex battles during reprogramming in gametes and early embryos

Gamete and embryo development are indispensable processes for successful reproduction. Cells involved in these processes acquire pluripotency, the ability to differentiate into multiple different cell types, through a series of events known as reprogramming that lead to profound changes in histone and DNA methylation. While essential for pluripotency, this epigenetic remodelling removes constraints that normally limit the expression of genomic sequences known as transposable elements (TEs). Unconstrained TE expression can lead to many deleterious consequences including infertility, so organisms have evolved complex and potent mechanistic arsenals to target and suppress TE expression during reprogramming. This review will focus on the control of transposable elements in gametes and embryos, and one important TE suppressing system known as the PIWI pathway. This broadly conserved, small RNA-targeted silencing mechanism appears critical for fertility in many species and may participate in multiple aspects of gene regulation in reproduction and other contexts.

High somatic mutation and neoantigen burden are correlated with decreased progression-free survival in multiple myeloma

Tumor-specific mutations can result in immunogenic neoantigens, both of which have been correlated with responsiveness to immune checkpoint inhibitors in highly mutagenic cancers. However, early results of single-agent checkpoint inhibitors in multiple myeloma (MM) have been underwhelming. Therefore, we sought to understand the relationship between mutation and neoantigen landscape of MM patients and responsiveness to therapies. Somatic mutation burden, neoantigen load, and response to therapy were determined using interim data from the MMRF CoMMpass study (NCT01454297) on 664 MM patients. In this population, the mean somatic and missense mutation loads were 405.84(s=608.55) and 63.90(s=95.88) mutations per patient, respectively. There was a positive linear relationship between mutation and neoantigen burdens (R²=0.862). The average predicted neoantigen load was 23.52(s=52.14) neoantigens with an average of 9.40(s=26.97) expressed neoantigens. Survival analysis revealed significantly shorter progression-free survival (PFS) in patients with greater than average somatic missense mutation load (N=163, 0.493 vs 0.726 2-year PFS, P=0.0023) and predicted expressed neoantigen load (N=214, 0.555 vs 0.729 2-year PFS, P=0.0028). This pattern is maintained when stratified by disease stage and cytogenetic abnormalities. Therefore, high mutation and neoantigen load are clinically relevant risk factors that negatively impact survival of MM patients under current standards of care.

Pomalidomide-dexamethasone in refractory multiple myeloma: long-term follow-up of a multi-cohort phase II clinical trial

Despite therapeutic advances, multiple myeloma remains incurable, with limited options for patients with refractory disease. We conducted a large, multi-cohort clinical trial testing various doses and treatment schedules of pomalidomide and dexamethasone (Pom/dex) in patients with refractory multiple myeloma. Overall, 345 patients were enrolled to six cohorts based on number and type of prior lines of therapy, pomalidomide dose and schedule. Median prior lines of therapy were three with near universal prior exposure to proteasome inhibitors and/or immunomodulatory drugs. A confirmed response rate of 35% was noted for all cohorts (range 23-65%) with higher responses in cohorts with fewer prior lines of therapy. Median time to confirmed response was ⩽2 months and the longest progression-free survival and overall survival seen in any cohort were 13.1 and 47.9 months, respectively. Observed adverse reactions were as expected, with myelosuppression and fatigue being the most common hematologic and non-hematologic adverse events (AEs), respectively. Longer durations of treatment and response, higher response rates and fewer AEs were noted with the 2 mg pomalidomide dose. This is the longest follow-up data for Pom/dex in refractory multiple myeloma and will help shape the real-world utilization of this regimen.

Changes in uninvolved immunoglobulins during induction therapy for newly diagnosed multiple myeloma

Little is known about the impact of multiple myeloma (MM) treatment on uninvolved immunoglobulins (Ig). We identified 448 patients who received high-dose dexamethasone (HD-DEX), lenalidomide and dexamethasone (RD), bortezomib and dexamethasone (VD), bortezomib, cyclophosphamide and dexamethasone (VCD) or bortezomib, lenalidomide and dexamethasone (VRD) for newly diagnosed MM at our institution between 2000 and 2013, and who had available data on absolute lymphocyte count (ALC) and quantitative uninvolved Ig at baseline and at the end of four cycles of therapy. Changes in ALC and uninvolved Ig were significantly different across treatments, with VCD and HD-DEX producing reductions in uninvolved Ig, and RD, VD and VRD leading to increases in uninvolved Ig. In addition, treatment with RD, VD and VRD was independently associated with higher odds of achieving a ⩾25% increase in or normalization of the primary uninvolved Ig on multivariate analysis. Although achievement of a humoral response in the primary uninvolved Ig was associated with a higher odds of achieving VGPR or better after four cycles of therapy, it was not associated with improved overall survival. These data highlight the different mechanisms of action of MM drugs and point toward a possible role for the use of VCD in treating antibody-mediated autoimmune disease.

Evolving changes in disease biomarkers and risk of early progression in smoldering multiple myeloma

We studied 190 patients with smoldering multiple myeloma (SMM) at our institution between 1973 and 2014. Evolving change in monoclonal protein level (eMP) was defined as ⩾10% increase in serum monoclonal protein (M) and/or immunoglobulin (Ig) (M/Ig) within the first 6 months of diagnosis (only if M-protein ⩾3 g/dl) and/or ⩾25% increase in M/Ig within the first 12 months, with a minimum required increase of 0.5 g/dl in M-protein and/or 500 mg/dl in Ig. Evolving change in hemoglobin (eHb) was defined as ⩾0.5 g/dl decrease within 12 months of diagnosis. A total of 134 patients (70.5%) progressed to MM over a median follow-up of 10.4 years. On multivariable analysis adjusting for factors known to predict for progression to MM, bone marrow plasma cells ⩾20% (odds ratio (OR)=3.37 (1.30-8.77), P=0.013), eMP (OR=8.20 (3.19-21.05), P<0.001) and eHb (OR=5.86 (2.12-16.21), P=0.001) were independent predictors of progression within 2 years of SMM diagnosis. A risk model comprising these variables was constructed, with median time to progression of 12.3, 5.1, 2.0 and 1.0 years among patients with 0-3 risk factors respectively. The 2-year progression risk was 81.5% in individuals who demonstrated both eMP and eHb, and 90.5% in those with all three risk factors.

Quantification of circulating clonal plasma cells via multiparametric flow cytometry identifies patients with smoldering multiple myeloma at high risk of progression

The presence of high numbers of circulating clonal plasma cells (cPCs) in patients with smoldering multiple myeloma (SMM), detected by a slide-based immunofluorescence assay, has been associated with a shorter time to progression (TTP) to MM. The significance of quantifying cPCs via multiparameter flow cytometry, a much more readily available diagnostic modality, in patients with SMM has not been evaluated. This study evaluated 100 patients with a known or new diagnosis of SMM who were seen at the Mayo Clinic, Rochester from January 2008 until December 2013. Patients with ⩾150 cPCs (N=9) were considered to have high number of cPCs based on the 97% specificity and 78% PPV of progression to MM within 2 years of cPC assessment. The median TTP of patients with ⩾150 cPCs was 9 months compared with not reached for patients with <150 cPCs (P<0.001). Thus, quantification of cPCs via multiparametric flow cytometry identifies patients with SMM at very high risk of progression to MM within 2 years and warrants confirmation in larger studies. In the future, this may allow reclassification of such patients as having MM requiring therapy prior to them enduring end-organ damage.

Early relapse following initial therapy for multiple myeloma predicts poor outcomes in the era of novel agents

Outcomes for patients with multiple myeloma (MM) have improved in recent years owing to use of novel agents and high-dose therapy followed by autologous stem cell transplant (ASCT). We analyzed the outcomes of 511 consecutive patients treated with novel therapies at our institution between 2006 and 2014 to determine the impact of relapse within 12 months of initiating treatment. A total of 82 patients (16.0%) experienced early relapse, with median time to relapse of 8.0 months (95% confidence interval (CI); 6.3, 8.9). Median overall survival (OS) was significantly worse for this group at 21.0 months (95% CI; 16.3, 27.2) vs not reached (NR) (95% CI; 96.3, NR) for those with late relapse (P<0.001). Survival outcomes remained poor among early relapse patients irrespective of depth of response to initial therapy. In multivariate analysis, low albumin and high-risk cytogenetics predicted early relapse. Outcomes of early relapse from early ASCT were also considered; median OS from ASCT for those relapsing within 12 months was 23.1 months (95% CI; 15.7, 32.4) vs 122.2 months (95% CI; 111.5, 122.2) for the remaining patients (P<0.001). Early relapse remains a marker of poor prognosis in the current era, and such patients should be targeted for clinical trials.

Impact of childhood experience and adult well-being on eating preferences and behaviours

OBJECTIVES

To examine the relative contribution of childhood experience, measured by childhood violence and childhood happiness, and adult well-being on adult eating preferences and behaviours, independent of proximal factors such as current deprivation.

DESIGN

A cross-sectional, stratified, randomised sample survey using retrospective measures of childhood violence and happiness and self-reported measures of current well-being.

SETTING

The North West Region of England between September 2012 and March 2013.

PARTICIPANTS

Individuals aged 18-95-year-olds from randomly selected households (participation was successful for 90% of eligible households and 78% of the total visited addresses; n=11,243).

OUTCOMES

Dichotomised measures for preference of healthy foods or 'feel good' foods and low or high daily fruit and vegetable consumption.

RESULTS

After correcting for demographics, combined categories for childhood experience and dichotomised measures of adult well-being were found to be significantly related to adult food preferences and eating behaviours. Participants with unhappy and violent childhoods compared to those with happy and non-violent childhoods had adjusted ORs (95% CI, significance) of 2.67 (2.15 to 3.06, p<0.001) of having low daily fruit and vegetable intake (two or less portions) and 1.53 (1.29 to 1.81, p<0.001) of choosing 'feel good' foods over foods which were good for their long term health.

CONCLUSIONS

Daily intake of fruit and vegetables, linked to non-communicable diseases, and preference for 'feel good' foods, linked to obesity, are affected by childhood experience and adult well-being independent of demographic factors. Preventative interventions which support parent-child relationships and improve childhood experience are likely to reduce the development of poor dietary and other health-risk behaviours.

Improvement in renal function and its impact on survival in patients with newly diagnosed multiple myeloma

Renal impairment (RI) is seen in over a quarter of patients with newly diagnosed multiple myeloma (NDMM). It is not clear if reversal of RI improves the outcome to that expected for NDMM patients without RI. We evaluated 1135 consecutive patients with NDMM seen at the Mayo Clinic between January 2003 and December 2012. RI was defined as having a creatinine clearance (CrCl) <40ml/min. The median overall survival (OS) for patients with RI at diagnosis receiving and not receiving novel agent induction therapy was not reached vs 46 months (P<0.001). The median OS for patients with CrCl ⩾40 ml/min at diagnosis, CrCl <40 ml/min at diagnosis but improved to ⩾40 ml/min and CrCl <40 ml/min at diagnosis and remained <40 ml/min, were 112, 56 and 33 months, respectively (P<0.001). The complete renal response rate for patients with RI at diagnosis receiving novel agent induction therapy compared to the rest was 40 vs 16% (P<0.001). In conclusion, patients with reversal of RI have improved outcomes, but it remains inferior to patients with normal renal function at diagnosis. These results have implications for identifying early treatment strategies for patients at risk of developing renal insufficiency.

Continued improvement in survival in multiple myeloma: changes in early mortality and outcomes in older patients

Therapy for multiple myeloma (MM) has markedly changed in the past decade with the introduction of new drugs, but it is not clear whether the improvements have been sustained. We studied 1038 patients diagnosed between 2001 and 2010, grouping patients into two 5-year periods by diagnosis, 2001-2005 and 2006-2010. The median estimated follow-up for the cohort was 5.9 years with 47% alive at the last follow-up. The median overall survival (OS) for the entire cohort was 5.2 years: 4.6 years for patients in the 2001-2005 group compared with 6.1 years for the 2006-2010 cohort (P=0.002). The improvement was primarily seen among patients over 65 years, the 6-year OS improving from 31 to 56%, P<0.001. Only 10% of patients died during the first year in the latter group, compared with 16% in the earlier cohort (P<0.01), suggesting improvement in early mortality. The improved outcomes were linked closely to the use of one or more new agents in initial therapy. The current results confirm continued survival improvement in MM and highlight the impact of initial therapy with novel agents. Most importantly, we demonstrate that the improved survival is benefitting older patients and that early mortality in this disease has reduced considerably.

HSV-NIS, an oncolytic herpes simplex virus type 1 encoding human sodium iodide symporter for preclinical prostate cancer radiovirotherapy

Several clinical trials have shown that oncolytic herpes simplex virus type 1 (oHSV-1) can be safely administered to patients. However, virus replication in tumor tissue has generally not been monitored in these oHSV clinical trials, and the data suggest that its oncolytic potency needs to be improved. To facilitate noninvasive monitoring of the in vivo spread of an oHSV and to increase its antitumor efficacy, the gene coding for human sodium iodide symporter (NIS) was incorporated into a recombinant oHSV genome and the corresponding virus (oHSV-NIS) rescued in our laboratory. Our data demonstrate that a human prostate cancer cell line, LNCap, efficiently concentrates radioactive iodine after the cells have been infected in vitro or in vivo. In vivo replication of oHSV-NIS in tumors was noninvasively monitored by computed tomography/single-photon emission computed tomography imaging of the biodistribution of pertechnetate and was confirmed. LNCap xenografts in nude mice were eradicated by intratumoral administration of oHSV-NIS. Systemic administration of oHSV-NIS prolonged the survival of tumor-bearing mice, and the therapeutic effect was further enhanced by administration of ¹³¹I after the intratumoral spread of the virus had peaked. oHSV-NIS has the potential to substantially enhance the outcomes of standard therapy for patients with prostate cancer.

Using clinically approved cyclophosphamide regimens to control the humoral immune response to oncolytic viruses

Oncolytic viruses can be neutralized in the bloodstream by antiviral antibodies whose titers increase progressively with each exposure, resulting in faster virus inactivation and further reductions in efficacy with each successive dose. A single dose of cyclophosphamide (CPA) at 370 mg m(-2) was not sufficient to control the primary antiviral immune responses in mice, squirrel monkeys and humans. We therefore tested clinically approved multidose CPA regimens, which are known to kill proliferating lymphocytes, to determine if more intensive CPA therapy can more effectively suppress antiviral antibody responses during virotherapy. In virus-susceptible mice, primary antibody responses to intravenously (i.v.) administered oncolytic measles virus (MV) or vesicular stomatitis virus (VSV) were partially or completely suppressed, respectively, by oral (1 mg × 8 days) or systemic (3 mg × 4 days) CPA regimens initiated 1 day before virus. When MV- or VSV-immune mice were re-challenged with the respective viruses and concurrently treated with four daily systemic doses of CPA, their anamnestic antibody responses were completely suppressed and antiviral antibody titers fell significantly below pre-booster levels. We conclude that the CPA regimen of four daily doses at 370 mg m(-2) should be evaluated clinically with i.v. virotherapy to control the antiviral antibody response and facilitate effective repeat dosing.

Curative one-shot systemic virotherapy in murine myeloma

Current therapy for multiple myeloma is complex and prolonged. Antimyeloma drugs are combined in induction, consolidation and/or maintenance protocols to destroy bulky disease, then suppress or eradicate residual disease. Oncolytic viruses have the potential to mediate both tumor debulking and residual disease elimination, but this curative paradigm remains unproven. Here we engineered an oncolytic vesicular stomatitis virus to minimize its neurotoxicity, enhance induction of antimyeloma immunity, and facilitate noninvasive monitoring of its intratumoral spread. Using high resolution imaging, autoradiography and immunohistochemistry, we demonstrate that the intravenously administered virus extravasates from tumor blood vessels in immunocompetent myeloma-bearing mice, nucleating multiple intratumoral infectious centers which expand rapidly and necrose at their centers, ultimately coalescing to cause extensive tumor destruction. This oncolytic tumor debulking phase lasts only for 72 hours after virus administration, and is completed before antiviral antibodies become detectable in the bloodstream. Anti-myeloma T cells, cross-primed as the virus-infected cells provoke an antiviral immune response, then eliminate residual uninfected myeloma cells. The study establishes a curative oncolytic paradigm for multiple myeloma where direct tumor debulking and immune eradication of minimal disease are mediated by a single intravenous dose of a single therapeutic agent. Clinical translation is underway.

Polyinosinic acid decreases sequestration and improves systemic therapy of measles virus

Off target binding or vector sequestration can significantly limit the efficiency of systemic virotherapy. We report here that systemically administered oncolytic measles virus (MV) was rapidly sequestered by the mononuclear phagocytic system (MPS) of the liver and spleen in measles receptor CD46-positive and CD46-negative mice. Since scavenger receptors on Kupffer cells are responsible for the elimination of blood-borne pathogens, we investigated here if MV uptake was mediated by scavenger receptors on Kupffer cells. Pretreatment of cells with poly(I), a scavenger receptor ligand, reduced MV expression by 99% in murine (J774A.1) macrophages and by 50% in human (THP-1) macrophages. Pre-dosing of mice with poly(I) reduced MPS sequestration of MV and increased circulating levels of MV by 4 to 15-folds at 2 minutes post virus administration. Circulating virus was still detectable 30 mins post infusion in mice predosed with poly(I) while no detectable MV was found at 5–10 min post infusion if mice did not receive poly(I). MPS blockade by poly(I) enhanced virus delivery to human ovarian SKOV3ip.1 and myeloma KAS6/1 xenografts in mice. Higher gene expression and improved control of tumor growth was noted early post therapy. Based on these results, incorporation of MPS blockade into MV treatment regimens is warranted.

Pinhole micro-SPECT/CT for noninvasive monitoring and quantitation of oncolytic virus dispersion and percent infection in solid tumors

The purpose of our study was to validate the ability of pinhole micro-single-photon emission computed tomography/computed tomography (SPECT/CT) to 1) accurately resolve the intratumoral dispersion pattern and 2) quantify the infection percentage in solid tumors of an oncolytic measles virus encoding the human sodium iodide symporter (MV-NIS). NIS RNA level and dispersion pattern were determined in control and MV-NIS infected BxPC-3 pancreatic tumor cells and mouse xenografts using quantitative, real-time, reverse transcriptase, polymerase chain reaction, autoradiography, and immunohistochemistry (IHC). Mice with BxPC-3 xenografts were imaged with ¹²³I or ⁹⁹TcO₄ micro-SPECT/CT. Tumor dimensions and radionuclide localization were determined with imaging software. Linear regression and correlation analyses were performed to determine the relationship between tumor infection percentage and radionuclide uptake (% injected dose per gram) above background and a highly significant correlation was observed (r² = 0.947). A detection threshold of 1.5-fold above the control tumor uptake (background) yielded a sensitivity of 2.7% MV-NIS infected tumor cells. We reliably resolved multiple distinct intratumoral zones of infection from noninfected regions. Pinhole micro-SPECT/CT imaging using the NIS reporter demonstrated precise localization and quantitation of oncolytic MV-NIS infection and can replace more time-consuming and expensive analyses (eg, autoradiography and IHC) that require animal sacrifice.

Pomalidomide (CC4047) plus low dose dexamethasone (Pom/dex) is active and well tolerated in lenalidomide refractory multiple myeloma (MM)

Patients with multiple myeloma progressing on current therapies have limited treatment options. Pomalidomide (CC4047), an immunomodulatory drug, has significant activity in relapsed myeloma and previous studies suggest activity in lenalidomide refractory disease. To better define its efficacy in this group, we treated a cohort of lenalidomide refractory patients. Pomalidomide was given orally (2 mg) daily, continuously in 28-day cycles along with dexamethasone (40 mg) given weekly. Responses were assessed by the International Myeloma Working Group Criteria. Thirty-four patients were enrolled. The best response was very good partial response in 3 (9%), partial response (PR) in 8 (23%), best responses (MR) in 5 (15%), stable disease in 12 (35%) and progressive disease in 6 (18%), for an overall response rate of 47%. Of the 14 patients that were considered high risk, 8 (57%) had responses including 4 PR and 4 MR. The median time to response was 2 months and response duration was 9.1 months, respectively. The median overall survival was 13.9 months. Toxicity was primarily hematologic, with grade 3 or 4 toxicity seen in 18 patients (53%) consisting of anemia (12%), thrombocytopenia (9%) and neutropenia (26%). The combination of pomalidomide and dexamethasone (Pom/dex) is highly active and well tolerated in patients with lenalidomide-refractory myeloma.

Population structure and historical biogeography of European Arabidopsis lyrata

Understanding the natural history of model organisms is important for the effective use of their genomic resources. Arabidopsis lyrata has emerged as a useful plant for studying ecological and evolutionary genetics, based on its extensive natural variation, sequenced genome and close relationship to A. thaliana. We studied genetic diversity across the entire range of European Arabidopsis lyrata ssp. petraea, in order to explore how population history has influenced population structure. We sampled multiple populations from each region, using nuclear and chloroplast genome markers, and combined population genetic and phylogeographic approaches. Within-population diversity is substantial for nuclear allozyme markers (mean P=0.610, A(e)=1.580, H(e)=0.277) and significantly partitioned among populations (F(ST)=0.271). The Northern populations have modestly increased inbreeding (F(IS)=0.163 verses F(IS)=0.093), but retain comparable diversity to central European populations. Bottlenecks are common among central and northern Europe populations, indicating recent demographic history as a dominant factor in structuring the European diversity. Although the genetic structure was detected at all geographic scales, two clear differentiated units covering northern and central European areas (F(CT) =0.155) were identified by Bayesian analysis and supported by regional pairwise F(CT) calculations. A highly similar geographic pattern was observed from the distribution of chloroplast haplotypes, with the dominant northern haplotypes absent from central Europe. We conclude A. l. petraea's cold-tolerance and preference for disturbed habitats enabled glacial survival between the alpine and Nordic glaciers in central Europe and an additional cryptic refugium. While German populations are probable peri-glacial leftovers, Eastern Austrian populations have diversity patterns possibly compatible with longer-term survival.

Measles virus as an oncolytic vector platform

Viral vector systems are widely being used in the development of new genetic approaches for a variety of human diseases. Oncolytic viruses have shown great potential as cancer therapeutics. The ideal viral vector for cancer gene therapy eradicates a clinically significant fraction of malignant cells and leaves normal tissues unharmed. The Edmonston vaccine strain of measles virus is a replicating RNA virus which is characterized by its tumor selectivity and oncolysis. Its strong tumor suppressive potential combined with its excellent safety record as a viral vaccine makes it an optimal platform for oncolytic virotherapy of cancer. Recent advances in genetic engineering of measles virus allow insertion of therapeutic and diagnostic transgenes as well as complete retargeting of measles virus. These strategies resulted in the generation of recombinant measles viruses allowing non-invasive monitoring of viral replication and viral spread. The immune defense is a significant barrier for efficient viral gene therapy. Immune-evasive strategies have successfully been developed for measles virus enhancing its efficacy. This review gives an overview of measles virus as an anticancer agent; in particular, its use in oncologic virotherapy as well as new developments in targeting and immune evasive strategies.

Preclinical pharmacology and toxicology of intravenous MV-NIS, an oncolytic measles virus administered with or without cyclophosphamide

MV-NIS is an oncolytic measles virus encoding the human thyroidal sodium iodide symporter (NIS). Here, we report the results of preclinical pharmacology and toxicology studies conducted in support of our clinical protocol "Phase I Trial of Systemic Administration of Edmonston Strain of Measles Virus, Genetically Engineered to Express NIS, with or without Cyclophosphamide, in Patients with Recurrent or Refractory Multiple Myeloma." Dose-response studies in the KAS-6/1 myeloma xenograft model demonstrated a minimum effective dose of 4 x 10(6) TCID50 (tissue culture infectious dose 50)/kg. Toxicity studies in measles-naive squirrel monkeys and measles-susceptible transgenic mice were negative at intravenous doses up to 10(8) and 4 x 10(8) TCID50/kg, respectively. Abundant viral mRNA, maximal on day 8, was detected in cheek swabs of squirrel monkeys, more so after pretreatment with cyclophosphamide. On the basis of these data, the safe starting dose of MV-NIS for our clinical protocol was set at 1-2 x 10(4) TCID50/kg (10(6) TCID50 per patient).

Long-term outcomes in children with high-risk neuroblastoma treated with autologous stem cell transplantation

We retrospectively analysed the outcomes of children transplanted for high-risk neuroblastoma (NB) at a single institution predominantly transplanted with total body irradiation and chemotherapy. The aims of this study were to determine the prognostic impact of clinical and biological features and to document long-term health outcomes. Forty patients were transplanted with a single unpurged autograft. Fourteen patients died from disease progression and two from late complications of treatment. Twenty-three patients are alive at a median of 4.6 years from diagnosis. Kaplan-Meier estimates of overall survival at 2, 5 and 10 years are 76+/-7.0, 60.2+/-8.4 and 54.7+/-9.3% following transplant. Response to induction therapy was significantly associated with survival (P<0.01). Long-term complications included growth (100%) and pubertal failure (83%), hearing impairment (73%), orthopaedic complications (63%), renal impairment (47%) and thyroid abnormalities (36%). Intrinsic and acquired resistance to chemotherapy remains the major obstacle to improving outcomes in high-risk NB. Although patients with chemo-sensitive disease are less likely to experience a relapse, substantial therapy-related toxicities result in poor long-term health outcomes for survivors.

A practical guide to defining high-risk myeloma for clinical trials, patient counseling and choice of therapy

Clinical outcomes for multiple myeloma (MM) are highly heterogeneous and it is now clear that pivotal genetic events are the primary harbingers of such variation. These findings have broad implications for counseling, choice of therapy and the design and interpretation of clinical investigation. Indeed, as in acute leukemias and non-hodgkins lymphoma, we believe it is no longer acceptable to consider MM a single disease entity. As such, the accurate diagnosis of MM subtypes and the adoption of common criteria for the identification and stratification of MM patients has become critical. Herein, we provide a consensus high-risk definition and offer practical guidelines for the adoption of routine diagnostic testing. Although acknowledging that more refined classifications will continue to be developed, we propose that the definition of high-risk disease (any of the t(4;14), t(14;16), t(14;20), deletion 17q13, aneuploidy or deletion chromosome 13 by metaphase cytogenetics, or plasma cell labeling index >3.0) be adopted. This classification will identify most of the 25% of MM patients for whom current therapies are inadequate and for whom investigational regimens should be vigorously pursued. Conversely, the 75% of patients remaining have more favorable outcomes using existing - albeit non-curative - therapeutic options.

Evaluation of T cells as carriers for systemic measles virotherapy in the presence of antiviral antibodies

Neutralizing antiviral antibodies (Abs) can hinder systemic virotherapy. Here, we used activated T cells as carriers to deliver oncolytic measles viruses (MV) to multiple myeloma xenografts in the presence of anti-MV antibodies (Abs). Virus-infected T cells expressing measles H/F fusogenic envelope glycoproteins could efficiently transfer MV infection by heterofusion, even after exposure to virus-inactivating anti-MV antisera. Severe-combined immunodeficiency (SCID) mice bearing subcutaneous or disseminated human myeloma xenografts were given MV-luciferase (MV-Luc) or MV-Luc-infected T cells intravenously. Indium111 labeling indicated that 1-2% of the virus-infected T cells trafficked to tumors. Preinfected T cells fused with tumor cells in vivo and transferred MV-Luc to tumor xenografts where intratumoral viral spread was monitored non-invasively using bioluminescent imaging. In mice passively immunized with high titers of measles immune serum, intravenous virus and cell delivery were both inhibited. Decreasing the amount of measles immune serum given to mice permitted tumor infection by virus-infected T cells and cell-free virus. In conclusion, virus-loaded T cells may facilitate systemic measles virotherapy in the presence of antiviral Abs and they warrant further investigation as potential MV cell carriers.

Pharmacokinetics of oncolytic measles virotherapy: eventual equilibrium between virus and tumor in an ovarian cancer xenograft model

Because of their ability to replicate, the dose-response relationships of oncolytic viruses cannot easily be predicted. To better understand the pharmacokinetics of virotherapy in relation to viral dose and schedule, we administered MV-CEA intraperitoneally in an orthotopic mouse model of ovarian cancer. MV-CEA is an attenuated oncolytic measles virus engineered to express soluble human carcinoembryonic antigen (CEA), and the virus is currently undergoing phase I clinical testing in patients with ovarian cancer. Plasma CEA levels correlate with numbers of virus-infected tumor cells at a given time, and were used as a surrogate to monitor the profiles of viral gene expression over time. The antineoplastic activity of single- or multiple-dose MV-CEA was apparent over a wide range of virus doses (10(3)-10(8) TCID(50)), with little reduction in observed antitumor efficacy, even at the lowest tested dose. However, analysis of CEA profiles of treated mice was highly informative, illustrating the variability in virus kinetics at different dose levels. The highest doses of virus were associated with higher initial levels of tumor cell killing, but the final outcome of MV-CEA therapy at all dose levels was a partial equilibrium between virus and tumor, resulting in significant slowing of tumor growth and enhanced survival of the mice.

Library-based selection of retroviruses selectively spreading through matrix metalloprotease-positive cells

Viruses conditionally replicating in cancer cells form an attractive novel class of antitumoral agents. To engineer such viruses infectivity can be coupled with proteolytic activity of the target cell by modifying the envelope (Env) protein of murine leukaemia virus (MLV) with blocking domains that prevent cell entry unless they are cleaved off by tumour-associated proteases like the matrix metalloproteases (MMP). Here we show that MLV variants selectively spreading through MMP-positive cells can be evolved from virus libraries, in which a standard MMP-2 substrate peptide connecting the blocking domain CD40L with the Env protein was diversified. Passaging the virus library on human fibrosarcoma or glioma cell lines resulted in the selection of about 10 virus clones, of which the three most frequent ones were shown to become activated by MMPs and to be replication competent on MMP-positive cells only. On these cells, the selected linker peptides improved the spreading by several orders of magnitude in vitro, as well as in tumour xenografts in vivo, approaching the kinetic of the unmodified wild-type virus. The data suggest that retroviral protease substrate libraries form a potent tool for the engineering of viruses conditionally replicating in a given cancer cell type of interest.

Targeting virus entry and membrane fusion through specific peptide/MHC complexes using a high-affinity T-cell receptor

The T-cell receptor (TCR) determines the specificity of T-cell recognition by binding to peptide fragments of intracellular proteins presented at the cell surface in association with molecules of the major histocompatibility complex (MHC). Engagement of the TCR by its cognate peptide/MHC ligand, with appropriate co-stimulatory signals, leads to activation of T-cell effector functions. Here we show that the attachment proteins of attenuated measles viruses, engineered to display a high-affinity single-chain TCR (scTCR), can recognize and bind to specific peptide-MHC complexes and thereby mediate targeted virus-cell entry and cell-to-cell fusion. Using the 2C TCR and its peptide/MHC ligand (SIYRYYGL/mouse K(b)), we show that a scTCR grafted onto the measles virus H protein confers new specificity to virus entry and cell fusion. The efficiency of TCR-mediated virus entry was dependent on the number of peptide/MHC complexes expressed on the target cells, increasing progressively above densities higher than 2500 complexes per cell. This work introduces a new paradigm for targeting virus entry and membrane fusion by extending the repertoire of targets to specific peptide-MHC ligands and offering a novel quantitative readout for the cellular expression of peptide-MHC complexes.

Targeting retroviral and lentiviral vectors

Retroviral vectors capable of efficient in vivo gene delivery to specific target cell types or to specific locations of disease pathology would greatly facilitate many gene therapy applications. The surface glycoproteins of membrane-enveloped viruses stand among the choice candidates to control the target cell receptor recognition and host range of retroviral vectors onto which they are incorporated. This can be achieved in many ways, such as the exchange of glycoprotein by pseudotyping, their biochemical modifications, their conjugation with virus-cell bridging agents or their structural modifications. Understanding the fundamental properties of the viral glycoproteins and the molecular mechanism of virus entry into cells has been instrumental in the functional alteration of their tropism. Here we briefly review the current state of our understanding of the structure and function of viral envelope glycoproteins and we discuss the emerging targeting strategies based on retroviral and lentiviral vector systems.

Directed evolution of retroviruses activatable by tumour-associated matrix metalloproteases

Protease-activatable retroviral vectors offer the possibility of targeted gene transfer into cancer cells expressing a unique set of proteases as, for example, the matrix metalloproteases (MMPs). However, it is difficult to predict which substrate sequence will be optimally cleaved by a given tumour cell type. Therefore, we developed a novel approach that allows the selection of MMP-activatable retroviruses from libraries of viruses displaying combinatorially diversified protease substrates. Starting from a virus harbouring a standard MMP-2 substrate motif, after only two consecutive cycles of diversification and in vivo selection, MMP-activatable viruses were recovered. Biochemical characterization of the selected viruses revealed that their linker peptides showed a considerably increased sensitivity for MMP-2 cleavage, and interestingly also improved the particle incorporation rate of the Env protein. Owing to the optimized linker peptide, the selected viruses exhibited a greatly enhanced spreading efficiency through human fibrosarcoma cells, while having retained the dependency on MMP activation. Moreover, cell entry efficiency and virus titres were considerably improved as compared to the parental virus displaying the standard MMP-2 substrate. The results presented imply that retroviral protease substrate libraries allow the definition of MMP substrate specificities under in vivo conditions as well as the generation of optimally adapted tumour-specific viruses.

Targeting the cytotoxicity of fusogenic membrane glycoproteins in gliomas through protease-substrate interaction

Fusogenic membrane glycoproteins (FMG) are potent therapeutic transgenes with potential utility in the gene therapy of gliomas. FMG expression constructs caused massive syncytia formation followed by cytotoxic cell death in glioma cell lines, and antitumor activity has been shown in glioma xenografts. FMG-induced fusion in glioma cells can involve heterologous cell lines including normal astrocytes and fibroblasts, therefore making targeting important. Here we report on the use of matrix metalloproteinase (MMP) cleavable linkers to target cytotoxicity of FMGs against gliomas. Expression constructs were made expressing the hyperfusogenic version of the Gibbon Ape Leukemia Virus envelope glycoprotein (GALV) linked to a blocking ligand (the C-terminal extracellular domain of CD40 ligand) via either an MMP cleavable linker (GALV M40), a factor Xa protease cleavable linker (GALV X40), or a noncleavable linker (GALV N40). Unmodified GALV expressing constructs were used as positive controls. The glioma cell lines U87, U118, and U251 previously characterized by zymography and MMP-2 activity assay as high, medium, and low MMP expressors, respectively; normal human astrocytes and the MMP-poor cell line TE671 were transfected with the GALV, GALV N40, GALV X40, and GALV M40 constructs. In contrast to unmodified GALV constructs, transfection with GALV X40 and GALV N40 constructs blocked fusion and cytotoxic cell death. Fusion occurred, however, after transfection with constructs containing MMP cleavable linkers to an extent dependent on MMP expression in the specific cell line. Use of the broad-spectrum MMP inhibitors, 1,10-phenanthroline and N-hydroxy-piperazine-carboxamide completely abolished the ability of MMP constructs to induce fusion. In cell mixing experiments, mixing of MMP-poor cell lines transfected with GALV M40 constructs with the MMP overexpressing untransfected U87 glioma cells led to partial restoration of fusion. Use of U87 supernatant did result in a similar effect. Establishment of stable tranfectants expressing the membrane-type MMPs, MT-1 MMP and MT-2 MMP did restore fusion in the MMP-poor cell line TE671 after transfection with GALV M40, thus indicating that both membrane-type MMPs and soluble MMPs activate the MMP cleavable constructs. In addition, the GALV M40 construct retained its cytotoxic activity against U87 cells in vivo, although less effectively as compared to unmodified GALV. Our data indicate that GALV-induced cytotoxicity in glioma cell lines can be blocked by display of the CD40 ligand. Incorporation of an MMP cleavable linker can selectively restore cytotoxicity in MMP expressing glioma cell lines both in vitro and in vivo, while sparing normal human astrocytes. Given the high frequency of MMP overexpression in gliomas, this represents a promising targeting strategy.

A direct mechanical method for accurate and efficient adenoviral vector delivery to tissues

We describe a mechanical method for delivery of adenoviral vector to the adventitial surface of arteries and to other tissues. Our goal was to characterize, principally in intact carotid artery, the morphological, biochemical, and functional effects of mechanical delivery of a recombinant beta-galactosidase-expressing adenoviral vector following its direct application using a small paintbrush. Our ex vivo and in vivo data demonstrate efficient, accurate, and rapid transduction of arteries without compromise of their morphological, biochemical, and functional integrity. We also demonstrate the general applicability of this technique in vivo via transduction of skeletal muscle, fibrotendinous tissue, peritoneum, serosal surface of bowel, and wounded skin. We conclude that direct mechanical delivery of an adenoviral vector to tissues using a suitable paintbrush represents an intuitive, accurate, and effective means of augmenting gene transfer efficiency, and may be a useful adjunct to other delivery methods.

Polyploidy, phylogeography and Pleistocene refugia of the rockfern Asplenium ceterach: evidence from chloroplast DNA

Chloroplast DNA sequences were obtained from 331 Asplenium ceterach plants representing 143 populations from throughout the range of the complex in Europe, plus outlying sites in North Africa and the near East. We identified nine distinct haplotypes from a 900 bp fragment of trnL-trnF gene. Tetraploid populations were encountered throughout Europe and further afield, whereas diploid populations were scarcer and predominated in the Pannonian-Balkan region. Hexaploids were encountered only in southern Mediterranean populations. Four haplotypes were found among diploid populations of the Pannonian-Balkans indicating that this region formed a northern Pleistocene refugium. A separate polyploid complex centred on Greece, comprises diploid, tetraploid and hexaploid populations with two endemic haplotypes and suggests long-term persistence of populations in the southern Mediterranean. Three chloroplast DNA (cpDNA) haplotypes were common among tetraploids in Spain and Italy, with diversity reducing northwards suggesting expansion from the south after the Pleistocene. Our cpDNA and ploidy data indicate at least six independent origins of polyploids.

Single-chain antibody-based gene therapy: inhibition of tumor growth by in situ production of phage-derived human antibody fragments blocking functionally active sites of cell-associated matrices

Experimental evidence suggests that blocking the interactions between endothelial cells and extracellular matrix (ECM) components may provide a potent and general strategy to inhibit tumor neovascularization. Based on these considerations, we have focused our efforts on laminin, component of the vascular basement membrane of every tumor-associated vessel, which serves an essential role in tube formation. We screened anti-laminin single-chain antibody fragments (scFv) derived from a human phage-display library and identified one that blocks the formation of capillary-like structures in vitro. This scFv inhibits angiogenesis in vivo in the chick embryo chorioallantoic membrane assay and prevents the establishment and growth of subcutaneous tumors in mice, either when administered as bolus protein therapy or when produced locally by gene-modified tumor cells. Our work represents the first demonstration of a direct in vivo therapeutic effect of a single-chain antibody secreted by gene-modified mammalian cells. These results open the way for a new antibody-based gene therapy strategy of cancer.