Prolonged Mechanical Circumferential Stretch Induces Metabolic Changes in Rat Inferior Vena Cava

OBJECTIVE/BACKGROUND

Circumferential stretch on the vein wall has been suggested as a potential etiological factor in the development of varicose veins. However, the influence of vein wall stretch on vein metabolism has not yet been explored. The aim of this study was to investigate the effect of short and prolonged mechanical stretch on vein wall metabolism.

METHODS

Circular segments of inferior vena cava from male Sprague-Dawley rats were exposed to normal 0.5-g (nonstretched) or high 2-g (stretched) tension for short (4 h) or prolonged (18 h) duration (five vein segments per group). Contraction response to phenylephrine (10^-5 M) and KCl (96 mM) was elicited to observe the effect of circumferential stretch on vein function. The polar and organic metabolites in vein tissue were extracted using a bilayer extraction method. Aqueous and organic extracts were analyzed using nuclear magnetic resonance spectroscopy and ultra performance liquid chromatography coupled to mass spectrometry, respectively. Data acquired from both analytical platforms were analyzed using mathematical modeling.

RESULTS

Increased concentrations of valine (p = .02) and choline (p = .03) metabolites and triglyceride moieties (p = .03) were observed in veins stretched for 18 h compared with the nonstretched/18 h group.

DISCUSSION

Increased concentrations of branched chain amino acid valine and cell membrane constituent choline indicate increased muscle breakdown and increased metabolism of membrane phospholipids under stretch in an ex-vivo model. Increased intensities of triglyceride moieties in stretched vein segments for 18 h suggest that high pressure may induce an inflammatory response.

CONCLUSION

This study has shown that prolonged mechanical circumferential stretch (18 h) alters the metabolic profile of rat inferior vena cava.

PIK3CA mutations are associated with reduced pathological complete response rates in primary HER2-positive breast cancer: pooled analysis of 967 patients from five prospective trials investigating lapatinib and trastuzumab

BACKGROUND

The predictive value of PIK3CA mutations in HER2 positive (HER2+) breast cancer treated with neoadjuvant anti-HER2 and chemotherapy has been reported, but the power for subgroup analyses was lacking.

PATIENTS AND METHODS

We combined individual patient data from five clinical trials evaluating PIK3CA mutations and associations with pathological complete response (pCR), disease-free survival (DFS) and overall survival (OS). Patients received either trastuzumab (T), lapatinib (L) or the combination T/L in addition to a taxane-based chemotherapy. PIK3CA was genotyped in tumour biopsies taken before therapy.

RESULTS

A total of 967 patients were included in this analysis; the median follow-up is 47 months. Overall, the pCR rate was significantly lower in the PIK3CA mutant compared with the wild-type group (16.2% versus 29.6%; P < 0.001). Within the hormone-receptor positive (HR+) subgroup, the PIK3CA mutant group had a pCR rate of only 7.6% compared with 24.2% in the wild-type group (P < 0.001). In contrast, in the HER2+/HR- group, there was no difference in pCR (27.2% versus 36.4%; P = 0.125) according to PIK3CA mutation status (interaction test P = 0.036). According to treatment arm, the pCR rate for mutant versus wild-type was 20.3% versus 27.1% for T (P = 0.343), 11.3% versus 16.9% for L (P = 0.369) and 16.7% versus 39.1% for T/L (P < 0.001). In the HR+ T/L group, the pCR rate was 5.5% versus 33.9% (interaction between HR and PIK3CA genotype P = 0.008). DFS and OS were not significantly different by mutation status, though the incidence rate of events was low. However, HR+/PIK3CA mutant patients seemed to have significantly worse DFS {hazard ratio (HR) 1.56 [95% confidence interval (CI) 1.00-2.45], P = 0.050; Pinteraction = 0.021}. T/L tended to improve DFS compared with T in the wild-type cohort, especially in the HR- group [HR 0.72, 95% CI (0.41-1.25), P = 0.242].

CONCLUSION

Overall PIK3CA mutant/HER2+ tumours had significantly lower pCR rates compared with wild-type tumours, however mainly confined to the HR+/PIK3CA mutant population. No definite conclusions can be drawn regarding survival.

Metabolic Phenotypes of Carotid Atherosclerotic Plaques Relate to Stroke Risk: An Exploratory Study

OBJECTIVE

Stroke is a major cause of death and disability. That three-quarters of stroke patients will never have previously manifested cerebrovascular symptoms demonstrates the unmet clinical need for new biomarkers able to stratify patient risk and elucidation of the biological dysregulations. In this study, the utility of comprehensive metabolic phenotyping is assessed to provide candidate biomarkers that relate to stroke risk in stenosing carotid plaque tissue samples.

METHOD

Carotid plaque tissue samples were obtained from patients with cerebrovascular symptoms of carotid origin (n = 5), and from asymptomatic patients (n = 5). Two adjacent biological replicates were obtained from each tissue. Organic and aqueous metabolite extracts were obtained separately and analysed using two ultra performance liquid chromatography coupled to mass spectrometry metabolic profiling methods. Multivariate and univariate tools were used for statistical analysis.

RESULTS

The two study groups demonstrated distinct plaque phenotypes using multivariate data analysis. Univariate statistics also revealed metabolites that differentiated the two groups with a strong statistical significance (p = 10(-4)-10(-5)). Specifically, metabolites related to the eicosanoid pathway (arachidonic acid and arachidonic acid precursors), and three acylcarnitine species (butyrylcarnitine, hexanoylcarnitine, and palmitoylcarnitine), intermediates of the β-oxidation, were detected in higher intensities in symptomatic patients. However, metabolites implicated in the process of cell death, a process known to be upregulated in the formation of the vulnerable plaque, were unaffected.

CONCLUSIONS

Discrimination between symptomatic and asymptomatic carotid plaque tissue is demonstrated for the first time using metabolic profiling technologies. Two biological pathways (eicosanoid and β-oxidation) were implicated in differentiating symptomatic from asymptomatic patients and will be further investigated. These results indicate that metabolic phenotyping should be further explored to investigate the chemistry of the unstable plaque, in the pursuit of candidate biomarkers for risk-stratification and targets for pharmacotherapeutic intervention.

Abstract S5-01: Whole exome sequencing of pre-treatment biopsies from the neoALTTO trial to identify DNA aberrations associated with response to HER2-targeted therapies

Background: We examined if alterations in nucleic acid variants, genes, pathways, and overall mutational load and clonal entropy are associated with pathologic complete response (pCR) and survival after neoadjuvant anti-HER2 therapies in the NeoALTTO trial.

Methods: Whole exome sequencing was performed of 203 baseline biopsies with outcome information. The mean nucleotide coverage was 150x with &gt;90% of target bases showing &gt; 30x coverage in &gt; 99% of samples. Somatic mutations were called by MuTect and indels by Strelka, using pooled reference normal DNA. Significantly mutated genes (FDR&lt;10%) were identified by MutSigCV. Mutations in 714 canonical biological pathways were assessed and mutational load and genome clonal entropy (MATH) were calculated. Association with pCR and survival were evaluated by logistic regression adjusted for ER status and Cox-proportional hazards regression.

Results: Only 12 genes had mutation rates significantly above background and among these only PI3KCA was associated with lower pCR rate (OR=0.42, p=0.019). Genes with somatic mutations in more than 10 patients were also assessed, but none were associated with pCR or survival. Clonal entropy or adjusted mutation load also did not correlate with response. Mutations in 33 pathways showed significant association with response in the entire cohort. In the trastuzumab arm, 23 of the 33 pathways showed an association with response but none was independent of PIK3CA mutation. We constructed "PIK3CA-gene network" that included all unique genes (n=439) from theese 23 pathways. Of the 66 patients in the trastuzumab arm, 50 carried at least one mutation in one of the 439 genes and among these only 2 achieved pCR (4%) compared to 9 of 16 pCR (56%) among the wild type (OR=0.035; p &lt; 0.001). The same genes/mutations had little impact on pCR in the lapatinib arm (pCR 20%). In the lapatinib arm, mutations in 3 pathways conferred higher probability of pCR. The "Regulation of RhoA activity" pathway, had the most significant association with pCR in the entire cohort (OR=3.77, p=0.0009) and in the lapatininb (pCR 67% vs 17%, OR=14.8, p=0.008) and lapatinib + trastuzumab (OR=3.0, p=0.06) arms, but not in the trastuzumab arm (OR=1.4, p=0.7). Event free and overall survival were also significantly higher in patients who had mutations in this pathway. Twenty seven of the 48 genes in this pathway had mutations affecting 33 patients but different genes were affected in different individuals.

Conclusions: There are no high frequency recurrent single mutations associated with response to HER2-targeted therapies, other than PIK3CA. We identified several biological pathways, including RhoA activity, and a network of PIK3CA associated genes that are significantly associated with response when affected by mutations, however, different genes are mutated in different individuals.

Citation Format: Pusztai L, Shi W, Jiang T, Nuciforo P, Holmes E, Harbeck N, Sotiriou C, Rimm D, Hatzis C, de la Peña L, Armour A, Piccart-Gebhart M, Baselga J. Whole exome sequencing of pre-treatment biopsies from the neoALTTO trial to identify DNA aberrations associated with response to HER2-targeted therapies. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S5-01.

Role of metabolic phenotyping in understanding obesity and related conditions in Gulf Co-operation Council countries

Obesity is a major health concern in the Middle East and the incidence is rising in all sections of the population. Efforts to control obesity through diet and lifestyle interventions, and by surgical means, have had limited effect, and the gene-environment interactions underpinning the development of obesity and related pathologies such as metabolic syndrome, cardiovascular disease and certain cancers are poorly defined. Lifestyle, genetics, inflammation and the interaction between the intestinal bacteria and host metabolism have all been implicated in creating an obesogenic environment. We summarize the role of metabolic and microbial phenotyping in understanding the aetiopathogenesis of obesity and in characterizing the metabolic responses to surgical and non-surgical interventions, and explore the potential for clinical translation of this approach.

The Role of Speech and Language Therapy in Assessing and Managing Pharyngo-esophageal Diverticula

This study explores the contribution of Speech and Language Therapists (SLTs) to the assessment and management of patients presenting on videofluoroscopic swallow studies (VFSS) with a suspected pharyngo-oesophageal diverticulum. Records for all patients who attended for VFSS in an acute hospital over an eleven-year period were examined (N = 1820). Twenty patients were identified on VFSS as having a suspected diverticulum. Symptoms suggestive of a diverticulum were found during both bedside clinical examination and radiographic examination e.g. respiratory difficulties (n = 15; 75%), voice changes (n = 14; 70/0). VFSS confirmed a reduced risk of aspiration for 14 patients (70%) using a combination of fluid modification (n = 9; 45%), food modification (n = 13; 65%) and swallow strategies (n = 14; 70%). VFSS confirmed aspiration directly related to the diverticulum in 11 patients (55%). Findings indicate that SLTs have the opportunity to identify potential diverticula and implement behavioural management to reduce associated health risks. This is of particular importance to patients who are awaiting, or cannot undergo, surgical repair of their diverticulum.

Benefit to neoadjuvant anti-human epidermal growth factor receptor 2 (HER2)-targeted therapies in HER2-positive primary breast cancer is independent of phosphatase and tensin homolog deleted from chromosome 10 (PTEN) status

BACKGROUND

Assessment of phosphatase and tensin homolog deleted from chromosome 10 (PTEN) might be an important tool in identifying human epidermal growth factor receptor 2 (HER2)-positive breast cancer patients unlikely to derive benefit from anti-HER2 therapies. However, studies to date have failed to demonstrate its predictive role in any treatment setting.

PATIENTS AND METHODS

Prospectively collected baseline core biopsies from 429 early-stage HER2-positive breast cancer patients treated with trastuzumab, lapatinib, or their combination in the Neo-ALTTO study were stained using two anti-PTEN monoclonal antibodies (CST and DAKO). The association of PTEN status and PI3K pathway activation (defined as either PTEN loss and/or PIK3CA mutation) with total pathological complete response (tpCR) at surgery, event-free survival (EFS), and overall survival (OS) was evaluated.

RESULTS

PTEN loss was observed in 27% and 29% of patients (all arms, n = 361 and n = 363) for CST and DAKO, respectively. PTEN loss was more frequently observed in hormone receptor (HR)-negative (33% and 36% with CST and DAKO, respectively) compared with HR-positive tumours (20% and 22% with CST and DAKO, respectively). No significant differences in tpCR rates were observed according to PTEN status. PI3K pathway activation was found in 47% and 48% of patients (all arms, n = 302 and n = 301) for CST and DAKO, respectively. Similarly, tpCR rates were not significantly different for those with or without PI3K pathway activation. Neither PTEN status nor PI3K pathway activation were predictive of tpCR, EFS, or OS, independently of treatment arm or HR status. High inter-antibody and inter-observer agreements were found (>90%). Modification of scoring variables significantly affected the correlation between PTEN and HR status but not with tpCR.

CONCLUSION

These data show that PTEN status determination is not a useful biomarker to predict resistance to trastuzumab and lapatinib-based therapies. The lack of standardization of PTEN status determination may influence correlations between expression and relevant clinical end points.

CLINICAL TRIALS

This trial is registered with ClinicalTrials.gov: NCT00553358.

Metabolic phenotype-microRNA data fusion analysis of the systemic consequences of Roux-en-Y gastric bypass surgery

Background/Objectives:

Bariatric surgery offers sustained marked weight loss and often remission of type 2 diabetes, yet the mechanisms of establishment of these health benefits are not clear.

Subjects/Methods:

We mapped the coordinated systemic responses of gut hormones, the circulating miRNAome and the metabolome in a rat model of Roux-en-Y gastric bypass (RYGB) surgery.

Results:

The response of circulating microRNAs (miRNAs) to RYGB was striking and selective. Analysis of 14 significantly altered circulating miRNAs within a pathway context was suggestive of modulation of signaling pathways including G protein signaling, neurodegeneration, inflammation, and growth and apoptosis responses. Concomitant alterations in the metabolome indicated increased glucose transport, accelerated glycolysis and inhibited gluconeogenesis in the liver. Of particular significance, we show significantly decreased circulating miRNA-122 levels and a more modest decline in hepatic levels, following surgery. In mechanistic studies, manipulation of miRNA-122 levels in a cell model induced changes in the activity of key enzymes involved in hepatic energy metabolism, glucose transport, glycolysis, tricarboxylic acid cycle, pentose phosphate shunt, fatty-acid oxidation and gluconeogenesis, consistent with the findings of the in vivo surgery-mediated responses, indicating the powerful homeostatic activity of the miRNAs.

Conclusions:

The close association between energy metabolism, neuronal signaling and gut microbial metabolites derived from the circulating miRNA, plasma, urine and liver metabolite and gut hormone correlations further supports an enhanced gut-brain signaling, which we suggest is hormonally mediated by both traditional gut hormones and miRNAs. This transomic approach to map the crosstalk between the circulating miRNAome and metabolome offers opportunities to understand complex systems biology within a disease and interventional treatment setting.

Dominant components of the Thoroughbred metabolome characterised by (1) H-nuclear magnetic resonance spectroscopy: A metabolite atlas of common biofluids

REASONS FOR PERFORMING STUDY

Metabonomics is emerging as a powerful tool for disease screening and investigating mammalian metabolism. This study aims to create a metabolic framework by producing a preliminary reference guide for the normal equine metabolic milieu.

OBJECTIVES

To metabolically profile plasma, urine and faecal water from healthy racehorses using high resolution (1) H-nuclear magnetic resonance (NMR) spectroscopy and to provide a list of dominant metabolites present in each biofluid for the benefit of future research in this area.

STUDY DESIGN

This study was performed using 7 Thoroughbreds in race training at a single time point. Urine and faecal samples were collected noninvasively and plasma was obtained from samples taken for routine clinical chemistry purposes.

METHODS

Biofluids were analysed using (1) H-NMR spectroscopy. Metabolite assignment was achieved via a range of one- and 2-dimensional experiments.

RESULTS

A total of 102 metabolites were assigned across the 3 biological matrices. A core metabonome of 14 metabolites was ubiquitous across all biofluids. All biological matrices provided a unique window on different aspects of systematic metabolism. Urine was the most populated metabolite matrix with 65 identified metabolites, 39 of which were unique to this biological compartment. A number of these were related to gut microbial host cometabolism. Faecal samples were the most metabolically variable between animals; acetate was responsible for the majority (28%) of this variation. Short-chain fatty acids were the predominant features identified within this biofluid by (1) H-NMR spectroscopy.

CONCLUSIONS

Metabonomics provides a platform for investigating complex and dynamic interactions between the host and its consortium of gut microbes and has the potential to uncover markers for health and disease in a variety of biofluids. Inherent variation in faecal extracts along with the relative abundance of microbial-mammalian metabolites in urine and invasive nature of plasma sampling, infers that urine is the most appropriate biofluid for the purposes of metabonomic analysis.

Relation of raw and cooked vegetable consumption to blood pressure: the INTERMAP Study

Inverse associations have been reported of overall vegetable intake to blood pressure (BP); whether such relations prevail for both raw and cooked vegetables has not been examined. Here we report cross-sectional associations of vegetable intakes with BP for 2195 Americans ages 40-59 in the International Study of Macro/Micronutrients and Blood Pressure (INTERMAP) using four standardized multi-pass 24-h dietary recalls and eight BP measurements. Relations to BP of raw and cooked vegetables consumption, and main individual constituents were assessed by multiple linear regression. Intakes of both total raw and total cooked vegetables considered separately were inversely related to BP in multivariate-adjusted models. Estimated average systolic BP differences associated with two s.d. differences in raw vegetable intake (68 g per 1000 kcal) and cooked vegetable intake (92 g per 1000 kcal) were -1.9 mm Hg (95% confidence interval (CI): -3.1, -0.8; P=0.001) and -1.3 mm Hg (95% CI: -2.5, -0.2; P=0.03) without body mass index (BMI) in the full model; -1.3 mm Hg (95% CI: -2.4, -0.2; P=0.02) and -0.9 mm Hg (95% CI: -2.0, 0.2; P=0.1) with additional adjustment for BMI. Among commonly consumed individual raw vegetables, tomatoes, carrots, and scallions related significantly inversely to BP. Among commonly eaten cooked vegetables, tomatoes, peas, celery, and scallions related significantly inversely to BP.

Chemical mapping of the colorectal cancer microenvironment via MALDI imaging mass spectrometry (MALDI-MSI) reveals novel cancer-associated field effects

Matrix-assisted laser desorption ionisation imaging mass spectrometry (MALDI-MSI) is a rapidly advancing technique for intact tissue analysis that allows simultaneous localisation and quantification of biomolecules in different histological regions of interest. This approach can potentially offer novel insights into tumour microenvironmental (TME) biochemistry. In this study we employed MALDI-MSI to evaluate fresh frozen sections of colorectal cancer (CRC) tissue and adjacent healthy mucosa obtained from 12 consenting patients undergoing surgery for confirmed CRC. Specifically, we sought to address three objectives: (1) To identify biochemical differences between different morphological regions within the CRC TME; (2) To characterise the biochemical differences between cancerous and healthy colorectal tissue using MALDI-MSI; (3) To determine whether MALDI-MSI profiling of tumour-adjacent tissue can identify novel metabolic 'field effects' associated with cancer. Our results demonstrate that CRC tissue harbours characteristic phospholipid signatures compared with healthy tissue and additionally, different tissue regions within the CRC TME reveal distinct biochemical profiles. Furthermore we observed biochemical differences between tumour-adjacent and tumour-remote healthy mucosa. We have referred to this 'field effect', exhibited by the tumour locale, as cancer-adjacent metaboplasia (CAM) and this finding builds on the established concept of field cancerisation.

Long-term survival of children less than six years of age enrolled on the CCG-945 phase III trial for newly-diagnosed high-grade glioma: a report from the Children's Oncology Group

BACKGROUND

We analyzed the long-term survival of children under 6 years of age (<6 years) enrolled upon the Children's Cancer Group (CCG)-945 high-grade glioma (HGG) study to determine the impact of intrinsic biological characteristics as well as treatment upon both survival and quality of life (QOL) in this younger age population.

PROCEDURE

Analyses were undertaken on patients <6 years with institutionally diagnosed HGG enrolled on the CCG-945 trial. Comparisons of survival were performed for patients <3 years of age (<3 years) (treated with intent to avoid irradiation) versus those between 3 and 6 years of age (3-6 years) (treated with irradiation and chemotherapy) at diagnosis. Discordance between the institutional diagnoses of HGG and consensus-reviewed diagnoses led us to perform further survival analyses for both groups. We compared the two groups of patients for biological markers, and evaluated the neuropsychological and QOL outcomes of long-term survivors.

RESULTS

Patients <3 years (n = 49, 19.5% of all enrolled patients) at diagnosis had a 10-year EFS and OS of 29 ± 6.5% and 37.5 ± 7%, respectively, while for patients 3-6 years (n = 34, 13.5% of all enrolled patients) 10-year EFS and OS were 35 ± 8% and 36 ± 8%, respectively. Molecular marker analysis showed that a smaller proportion of patients <3 years harbored TP53 mutations (P = 0.05). Analysis of QOL outcomes with a median length of follow-up of 15.1 years (9.5-19.2) showed comparable results.

CONCLUSIONS

QOL and survival data were similar for the two groups. A larger prospective study is justified to study the efficacy of chemotherapy only regimens in younger children.

Abstract P1-08-09: EGFR expression is associated with decreased response from HER2 targeted therapeutics in the neo-adjuvant setting in the NeoALTTO trial

Background: Epidermal Growth Factor Receptor (EGFR, HER1) is known to heterodimerize with HER2 and may modulate the effectiveness of trastuzumab or lapatinib. Historically, it has been difficult to measure, but recently we reported a new, standardized, quantitative immunofluorescence assay and a novel EGFR antibody which showed that high levels of EGFR were associated with decreased benefit in the concurrent arm of the North Central Cancer Treatment Group (NCCTG/Alliance) N9831 trial (Rimm et al, SABCS 2012). Here we assess its value in the neo-adjuvant setting in the NeoALTTO trial.

Methods: NeoALTTO randomized 455 breast cancer patients to neoadjuvant trastuzumab, lapatinib or both and showed benefit in both single anti-HER2 therapy arms, and the combination therapy showing about twice as much benefit as either single drug arm. We used the previously described AQUA method of quantitative immunofluorescence to measure EGFR levels using the D38B1 antibody on between 4 and 140 fields of view per slide on 353 specimens. The averaged EGFR score was standardized to the absolute concentration using cell lines and western blots and the 13 ng/ug total protein established in the N9831 trial was tested to determine predictive value for pathological complete response (pCR) defined as ypT0/is.

Results: In NeoALTTO, 19% of the patients had EGFR levels above 13 ng/ug, compared to 16% in NCCTG N9831. The pCR rate was 35.3% in the patients with low EGFR, compared with 29.8% for high EGFR but this difference was not statistically significant. However, when adjusted for treatment and hormone receptor (HR) status, high EGFR is statistically significantly associated with lower response rate(p = 0.038). Continuous analysis measures were not significant. The effect on overall response at 6 weeks was also weakly significant when adjusting for treatment and HR status (p = 0.06). Surprisingly, for HR negative patients in the lapatinib only arm, the pCR rate in the low EGFR group was 47.2% compared with 16.0% in the high group. While this difference is statistically significant (p = 0.014), it should be interpreted cautiously because of the small numbers of patients and the multiple tests performed.

Conclusions: High expression of EGFR by the AQUA platform appears to be associated with decreased pCR rate from HER2 targeted therapy in the neoadjuvant setting. This observation is consistent with NCCTG N9831. Although underpowered, high EGFR levels predicted decreased pCR rate from lapatinib, the opposite of that anticipated for this small molecule dual EGFR/HER2 inhibitor. Further studies are required to determine the clinical utility of this assay and the biological mechanisms underlying these observations.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-09.