Enhanced ZAG production by subcutaneous adipose tissue is linked to weight loss in gastrointestinal cancer patients

Background:

Profound loss of adipose tissue is a hallmark of cancer cachexia. Zinc-α2-glycoprotein (ZAG), a recently identified adipokine, is suggested as a candidate in lipid catabolism.

Methods:

In the first study, eight weight-stable and 17 cachectic cancer patients (weight loss ⩾5% in previous 6 months) were recruited. Zinc-α2-glycoprotein mRNA and protein expression were assessed in subcutaneous adipose tissue (SAT), subcutaneous adipose tissue morphology was examined and serum ZAG concentrations were quantified. In the second cohort, ZAG release by SAT was determined in 18 weight-stable and 15 cachectic cancer patients. The effect of ZAG on lipolysis was evaluated in vitro.

Results:

Subcutaneous adipose tissue remodelling in cancer cachexia was evident through shrunken adipocytes with increased fibrosis. In cachectic cancer patients, ZAG mRNA was upregulated (2.7-fold, P=0.028) while leptin mRNA decreased (2.2-fold, P=0.018); serum ZAG levels were found to be unaffected. Zinc-α2-glycoprotein mRNA correlated positively with weight loss (r=0.51, P=0.01) and serum glycerol levels (r=0.57, P=0.003). Zinc-α2-glycoprotein release by SAT was also elevated in cachectic patients (1.5-fold, P=0.024) and correlated with weight loss (r=0.50, P=0.003). Recombinant ZAG stimulated lipolysis in human adipocytes.

Conclusions:

Zinc-α2-glycoprotein expression and secretion by adipose tissue is enhanced in cachectic cancer patients. Given its lipid-mobilising effect, ZAG may contribute to adipose atrophy associated with cancer cachexia in human beings.

Analgesic use during pregnancy and risk of infant leukaemia: a Children's Oncology Group study

Background:

Infant leukaemia is likely initiated in utero.

Methods:

We examined whether analgesic use during pregnancy was associated with risk by completing telephone interviews of the mothers of 441 infant leukaemia cases and 323 frequency-matched controls, using unconditional logistic regression.

Results:

With the exception of a reduced risk for infant acute myeloid leukaemias with non-aspirin non-steroidal anti-inflammatory drugs (NSAID) use early in pregnancy (odds ratios=0.60; confidence intervals: 0.37–0.97), no statistically significant associations were observed for aspirin, non-aspirin NSAIDs, or acetaminophen use in early pregnancy or after knowledge of pregnancy.

Conclusion:

Overall, analgesic use during pregnancy was not significantly associated with the risk of infant leukaemia.

Maternal vitamin and iron supplementation and risk of infant leukaemia: a report from the Children's Oncology Group

Background:

Prenatal supplementation has been inversely associated with childhood, but not with infant, leukaemia.

Methods:

Mothers of 443 cases of infant leukaemia diagnosed during 1996–2006 and 324 frequency-matched controls completed interviews. Associations were evaluated by unconditional logistic regression.

Results:

We observed no associations between prenatal vitamin (odds ratio (OR)=0.79, 95% confidence interval (CI): 0.44–1.42) or iron supplementation (OR=1.07, 95% CI: 0.75–1.52) and infant leukaemia after adjustment for race/ethnicity and income. Similar results were observed for leukaemia subtypes analysed separately.

Conclusion

The observed null associations may be attributable to high supplementation rates and/or national fortification programmes.

A potential microRNA signature for tumorigenic conazoles in mouse liver

Triadimefon, propiconazole, and myclobutanil are conazoles, an important class of agricultural fungicides. Triadimefon and propiconazole are mouse liver tumorigens, while myclobutanil is not. As part of a coordinated study to understand the molecular determinants of conazole tumorigenicity, we analyzed the microRNA expression levels in control and conazole-treated mice after 90 d of administration in feed. MicroRNAs (miRNAs) are small noncoding RNAs composed of approximately 19-24 nucleotides in length, and have been shown to interact with mRNA (usually 3' UTR) to suppress its expression. MicroRNAs play a key role in diverse biological processes, including development, cell proliferation, differentiation, and apoptosis. Groups of mice were fed either control diet or diet containing 1800 ppm triadimefon, 2500 ppm propiconazole, or 2000 ppm myclobutanil. MicroRNA was isolated from livers and analyzed using Superarray whole mouse genome miRNA PCR arrays from SABioscience. Data were analyzed using the significance analysis of microarrays (SAM) procedure. We identified those miRNAs whose expression was either increased or decreased relative to untreated controls with q < or = 0.01. The tumorigenic conazoles induced many more changes in miRNA expression than the nontumorigenic conazole. A group of 19 miRNAs was identified whose expression was significantly altered in both triadimefon- and propiconazole-treated animals but not in myclobutanil-treated animals. All but one of the altered miRNAs were downregulated compared to controls. This pattern of altered miRNA expression may represent a signature for tumorigenic conazole exposure in mouse liver after 90 d of treatment.

Abstract 2044: Altered microRNA expression induced by tumorigenic conazoles in mouse liver

Triadimefon, propiconazole, and myclobutanil are conazoles, an important class of agricultural and therapeutic fungicides. Triadimefon and propiconazole are mouse liver tumorigens, while myclobutanil is not. As part of a coordinated study to understand the molecular determinants of conazole tumorigenicity, we analyzed the microRNA expression levels in control and conazole treated mice after 90 days of administration in feed. Groups of mice were fed either control diet or diet containing 1800 p.p.m. triadimefon, 2500 p.p.m. propiconazole or 2000 p.p.m. myclobutanil. MicroRNA was isolated from livers and analyzed using Superarray whole mouse genome miRNA PCR arrays from SABioscience. Data were analyzed using the Significance Analysis of Microarrays (SAM) procedure. We identified those miRNAs whose expression was either increased or decreased relative to untreated controls with q ≤ 0.01. The tumorigenic conazoles induced many more changes in miRNA expression than the non-tumorigenic conazole. A group of 19 miRNAs was identified whose expression was significantly altered in both triadimefon and propiconazole treated animals but not in myclobutanil treated animals. All but one of the altered miRNAs were downregulated compared to controls. The greatest fold-changes in miRNA expression were observed for mmu-mir-135b and mmu-mir-684. Among the putative targets of the miRNAs altered by tumorigenic conazoles are genes involved in regulation of apoptosis and cell proliferation. This abstract does not reflect US EPA policy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2044.

Lack of contribution of covalent benzo[a]pyrene-7,8-quinone-DNA adducts in benzo[a]pyrene-induced mouse lung tumorigenesis

Benzo[a]pyrene (B[a]P) is a potent human and rodent lung carcinogen. This activity has been ascribed in part to the formation of anti-trans-7,8-dihydroxy-7,8-dihydroB[a]P-9,10-epoxide (BPDE)-DNA adducts. Other carcinogenic mechanisms have been proposed: (1) the induction of apurinic sites from radical cation processes, and (2) the metabolic formation of B[a]P-7,8-quinone (BPQ) that can form covalent DNA adducts or reactive oxygen species which can damage DNA. The studies presented here sought to examine the role of stable BPQ-DNA adducts in B[a]P-induced mouse lung tumorigenesis. Male strain A/J mice were injected intraperitoneally once with BPQ or trans-7,8-dihydroxy-7,8-dihydroB[a]P (BP-7,8-diol) at 30, 10, 3, or 0mg/kg. Lungs and livers were harvested after 24h, the DNA extracted and subjected to (32)P-postlabeling analysis. Additional groups of mice were dosed once with BPQ or BP-7,8-diol each at 30 mg/kg and tissues harvested 48 and 72 h later, or with B[a]P (50mg/kg, a tumorigenic dose) and tissues harvested 72 h later. No BPQ or any other DNA adducts were observed in lung or liver tissues 24, 48, or 72 h after the treatment with 30 mg/kg BPQ. BP-7,8-diol gave BPDE-DNA adducts at all time points in both tissues and B[a]P treatment gave BPDE-DNA adducts in the lung. In each case, no BPQ-DNA adducts were detected. Mouse body weights significantly decreased over time after BPQ or BP-7,8-diol treatments suggesting that systemic toxicity was induced by both agents. Model studies with BPQ and N-acetylcysteine suggested that BPQ is rapidly inactivated by sulfhydryl-containing compounds and not available for DNA adduction. We conclude that under these treatment conditions BPQ does not form stable covalent DNA adducts in the lungs or livers of strain A/J mice, suggesting that stable BPQ-covalent adducts are not a part of the complex of mechanisms involved in B[a]P-induced mouse lung tumorigenesis.

K-Ras mutant fraction in A/J mouse lung increases as a function of benzo[a]pyrene dose

K-Ras mutant fraction (MF) was measured to examine the default assumption of low-dose linearity in the benzo[a]pyrene (B[a]P) mutational response. Groups of 10 male A/J mice (7- to 9-weeks old) received a single i.p. injection of 0, 0.05, 0.5, 5, or 50 mg/kg B[a]P and were sacrificed 28 days after treatment. K-Ras codon 12 TGT and GAT MFs in lung DNAs were measured using Allele-specific Competitive Blocker-PCR (ACB-PCR). The K-Ras codon 12 TGT geometric mean MF was 3.88 x 10(-4) in controls, indicating an average of 1 mutation in every approximately 1,288 lung cells. The K-Ras codon 12 TGT geometric mean MFs were as follows: 3.56 x 10(-4); 6.19 x 10(-4); 2.02 x 10(-3), and 3.50 x 10(-3) for the 0.05, 0.5, 5, and 50 mg/kg B[a]P treatment groups, respectively. The 5 and 50 mg/kg dose groups had TGT MFs significantly higher than did controls. Although 10(-5) is considered as the limit of accurate ACB-PCR quantitation, K-Ras codon 12 GAT geometric mean MFs were as follows: 8.38 x 10(-7), 1.47 x 10(-6), 2.19 x 10(-6), 5.71 x 10(-6), and 8.99 x 10(-6) for the 0, 0.05, 0.5, 5, and 50 mg/kg B[a]P treatment groups, respectively. The K-Ras TGT and GAT MFs increased in a B[a]P-dose-dependent manner, with response approximately linear over the 0.05 to 5 mg/kg dose range. K-Ras MF increased with B[a]P adduct burden measured for identical doses in a separate study. Thus, ACB-PCR may be useful in characterizing the shape of a dose-response curve at low doses and establishing relationships between DNA adducts and tumor-associated mutations.

Plasma MIC-1 correlates with systemic inflammation but is not an independent determinant of nutritional status or survival in oesophago-gastric cancer

Background:

Macrophage inhibitory cytokine-1(MIC-1) is a potential modulator of systemic inflammation and nutritional depletion, both of which are adverse prognostic factors in oesophago-gastric cancer (OGC).

Methods:

Plasma MIC-1, systemic inflammation (defined as plasma C-reactive protein (CRP) of ⩾10 mg l^–1 or modified Glasgow prognostic score (mGPS) of ⩾1), and nutritional status were assessed in newly diagnosed OGC patients (n=293). Healthy volunteers (n=35) served as controls.

Results:

MIC-1 was elevated in patients (median=1371 pg ml^–1; range 141–39 053) when compared with controls (median=377 pg ml^–1; range 141–3786; P<0.001). Patients with gastric tumours (median=1592 pg ml^–1; range 141–12 643) showed higher MIC-1 concentrations than patients with junctional (median=1337 pg ml^–1; range 383–39 053) and oesophageal tumours (median=1180 pg ml^–1; range 258–31 184; P=0.015). Patients showed a median weight loss of 6.4% (range 0.0–33.4%), and 42% of patients had an mGPS of ⩾1 or plasma CRP of ⩾10 mg l^–1 (median=9 mg l^–1; range 1–200). MIC-1 correlated positively with disease stage (r²=0.217; P<0.001), age (r²=0.332; P<0.001), CRP (r²=0.314; P<0.001), and mGPS (r²=0.336; P<0.001), and negatively with Karnofsky Performance Score (r²=−0.269; P<0.001). However, although MIC-1 correlated weakly with dietary intake (r²=0.157; P=0.031), it did not correlate with weight loss, BMI, or anthropometry. Patients with MIC-1 levels in the upper quartile showed reduced survival (median=204 days; 95% CI 157–251) when compared with patients with MIC-1 levels in the lower three quartiles (median=316 days; 95% CI 259–373; P=0.036), but MIC-1 was not an independent prognostic indicator.

Conclusions:

There is no independent link between plasma MIC-1 levels and depleted nutritional status or survival in OGC.

Analysis of the mutations induced by conazole fungicides in vivo

The mouse liver tumorigenic conazole fungicides triadimefon and propiconazole have previously been shown to be in vivo mouse liver mutagens in the Big Blue transgenic mutation assay when administered in feed at tumorigenic doses, whereas the non-tumorigenic conazole myclobutanil was not mutagenic. DNA sequencing of the mutants recovered from each treatment group as well as from animals receiving control diet was conducted to gain additional insight into the mode of action by which tumorigenic conazoles induce mutations. Relative dinucleotide mutabilities (RDMs) were calculated for each possible dinucleotide in each treatment group and then examined by multivariate statistical analysis techniques. Unsupervised hierarchical clustering analysis of RDM values segregated two independent control groups together, along with the non-tumorigen myclobutanil. The two tumorigenic conazoles clustered together in a distinct grouping. Partitioning around mediods of RDM values into two clusters also groups the triadimefon and propiconazole together in one cluster and the two control groups and myclobutanil together in a second cluster. Principal component analysis of these results identifies two components that account for 88.3% of the variability in the points. Taken together, these results are consistent with the hypothesis that propiconazole- and triadimefon-induced mutations do not represent clonal expansion of background mutations and support the hypothesis that they arise from the accumulation of reactive electrophilic metabolic intermediates within the liver in vivo.

The influence of systemic inflammation, dietary intake and stage of disease on rate of weight loss in patients with gastro-oesophageal cancer

Although weight loss is often a dominant symptom in patients with upper gastrointestinal malignancy, there is a lack of objective evidence describing changes in nutritional status and potential associations between weight loss, food intake, markers of systemic inflammation and stage of disease in such patients. Two hundred and twenty patients diagnosed with gastric/oesophageal cancer were studied. Patients underwent nutritional assessment consisting of calculation of body mass index, measurement of weight loss, dysphagia scoring and estimation of dietary intake. Serum acute-phase protein concentrations were determined by enzyme-linked immunosorbent assay. In all, 182 (83%) patients had lost weight at diagnosis (median loss, 7% body weight). Weight loss was associated with poor performance status, advanced disease stage, dysphagia, reduced dietary intake and elevated serum C-reactive protein (CRP) concentrations. Multiple regression identified dietary intake (estimate of effect, 38%), serum CRP concentrations (estimate of effect, 34%) and stage of disease (estimate of effect, 28%) as independent variables in determining degree of weight loss. Mechanisms other than reduced dietary intake or mechanical obstruction by the tumour appear to be involved in the nutritional decline in patients with gastro-oesophageal malignancy. Recognition that systemic inflammation plays a role in nutritional depletion may inform the development of appropriate therapeutic strategies to ameliorate weight loss, making patients more tolerant of cancer-modifying treatments such as chemotherapy.

Periconceptional maternal vitamin supplementation and childhood leukaemia: an uncertainty analysis

BACKGROUND

Recent studies in childhood cancer suggest that maternal vitamin supplementation may reduce the risk of leukaemia, neuroblastoma and certain types of childhood brain tumours. For example, a previous study found a significantly reduced risk of acute lymphoblastic leukaemia (ALL) but not acute myeloid leukaemia (AML) in children with Down syndrome whose mothers reported any vitamin supplement use prior to knowledge of pregnancy (ALL OR adjusted for confounders 0.51, 95% confidence limits (CL): 0.30, 0.89; AML OR adjusted for confounders 0.92, 95% CL 0.48, 1.76). Recall of exposures, including maternal vitamin supplement use, however, may be difficult and subject to error. Epidemiologists are encouraged to quantitatively adjust for systematic error in study results, but often do not.

METHODS

The impact that misclassification of maternal vitamin supplement use may have had on the observed ORs in this study was quantified. Uncertainty analysis was used to calculate ORs adjusted for inaccurate reporting of vitamin supplement use under assumed probability distributions for exposure misclassification parameters.

RESULTS

Given our assumptions, adjustment for exposure misclassification yielded ORs that were predominantly more protective for ALL than the crude OR.

CONCLUSIONS

Uncertainty analysis can give important insights into the magnitude and direction of error in study results due to exposure misclassification.

Childhood cancer in the offspring born in 1921-1984 to US radiologic technologists

We examined the risk of childhood cancer (<20 years) among 105 950 offspring born in 1921-1984 to US radiologic technologist (USRT) cohort members. Parental occupational in utero and preconception ionising radiation (IR) testis or ovary doses were estimated from work history data, badge dose data, and literature doses (the latter doses before 1960). Female and male RTs reported a total of 111 and 34 haematopoietic malignancies and 115 and 34 solid tumours, respectively, in their offspring. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression. Leukaemia (n=63) and solid tumours (n=115) in offspring were not associated with maternal in utero or preconception radiation exposure. Risks for lymphoma (n=44) in those with estimated doses of <0.2, 0.2-1.0, and >1.0 mGy vs no exposure were non-significantly elevated with HRs of 2.3, 1.8, and 2.7. Paternal preconception exposure to estimated cumulative doses above the 95th percentile (82 mGy, n=6 cases) was associated with a non-significant risk of childhood cancer of 1.8 (95% CI 0.7-4.6). In conclusion, we found no convincing evidence of an increased risk of childhood cancer in the offspring of RTs in association with parental occupational radiation exposure.

Mutations induced by benzo[a]pyrene and dibenzo[a,l]pyrene in lacI transgenic B6C3F1 mouse lung result from stable DNA adducts

Dibenzo[a,l]pyrene (DB[a,l]P) and benzo[a]pyrene (B[a]P) are carcinogenic polycyclic aromatic hydrocarbons (PAHs) that are each capable of forming a variety of covalent adducts with DNA. Some of the DNA adducts formed by these PAHs have been demonstrated to spontaneously depurinate, producing apurinic (AP) sites. The significance of the formation of AP sites as a key event in the production of mutations and tumours by PAHs has been a subject of ongoing investigations. Because cells have efficient and accurate mechanisms for repairing background levels of AP sites, the contribution of PAH-induced AP site mutagenesis is expected to be maximal in conditions where those induced AP sites are produced in significant excess of the endogenous AP sites. In this study, we investigated the effect of two dosing regimens on the mutagenicity of DB[a,l]P and B[a]P in vivo using the Big Blue(R) transgenic mouse system. We compared administration of a single highly tumorigenic dose of each PAH with a fractionated delivery of the same total dose administered over 5 days, with the expectation that PAH-induced AP sites would be produced at a greater margin above background levels in animals receiving the high single dose than in the animals receiving the fractionated doses. Treatment with DB[a,l]P yielded a 2.5-fold (single dose) to 3-fold (fractionated dose) increase in mutant frequencies relative to controls. Both single-dose and fractionated dose treatment regimens with B[a]P produced about a 15-fold increase in mutant frequencies compared to controls. The mutations induced by B[a]P and DB[a,l]P correlated with the stable covalent DNA adducts produced by each. These mutation results are consistent with the previously identified stable covalent DNA adducts being the promutagenic lesions produced by these two PAHs and do not support a major role for depurinating adducts, contributing to PAH-induced mutagenesis in mouse lung in vivo.

Biomarkers for cancer cachexia: is there also a genetic component to cachexia?

INTRODUCTION

Cancer cachexia is a severe debilitating disorder, which causes significant morbidity and mortality. In clinical practice, cachexia is often not treated until a late stage, when therapeutic options are limited.

OBJECTIVE

It is therefore of great interest to analyse early biomarkers of this syndrome.

CONCLUSION

In this review article, we summarise recent biomarkers found in various body compartments. We also explore the likelihood of a genetic predisposition to cachexia and focus on the potential role of single nucleotide polymorphisms in genes coding for pro- and anti-inflammatory cytokines, and 'atrogenes' associated with wasting in skeletal muscle.

Nanomechanical probing of microbubbles using the atomic force microscope

Atomic force microscopy (AFM) is a versatile mechanical nanosensor that can be used to quantify the mechanical properties of microbubbles (MBs) and the adhesion mechanisms of targeted MBs. Mechanical properties were investigated using AFM tipless cantilevers to microcompress the MBs. The range of compressive stiffness for biSphere was found to be between 1 and 10Nm(-1) using a cantilever with a spring constant of 0.6 Nm(-1). This stiffness was shown to decrease with the MB size in a non-linear fashion. It is also possible to calculate a theoretical Young's modulus of the shell. The adhesion properties of targeted lipid based MBs that use avidin-biotin chemistry for the attachment of targeting ligands were also studied. The MBs were attached to poly-L-lysine treated tipless cantilevers with spring constants ranging from 0.03 to 0.1 Nm(-1). This system interrogated individual cells with pulling cantilever distance of 15 microm, and scan rate at 0.2 Hz. The depth of contact was not larger than 0.4 microm. The targeted MBs provided a significantly larger adhesion to the cells compared to control ones. Average adhesion force was dependent on depth of contact. Analysis of the data demonstrated a single distribution of adhesion events with median at 89 pN, which is in agreement with the literature for such interactions. The nanointerrogation of MBs using AFM provides new insight into their mechanical properties, and should be of assistance to MB design and manufacture.