NANOG controls testicular germ cell tumour stemness through regulation of MIR9-2

BACKGROUND

Testicular germ cell tumours (TGCTs) represent a clinical challenge; they are most prevalent in young individuals and are triggered by molecular mechanisms that are not fully understood. The origin of TGCTs can be traced back to primordial germ cells that fail to mature during embryonic development. These cells express high levels of pluripotency factors, including the transcription factor NANOG which is highly expressed in TGCTs. Gain or amplification of the NANOG locus is common in advanced tumours, suggesting a key role for this master regulator of pluripotency in TGCT stemness and malignancy.

METHODS

In this study, we analysed the expression of microRNAs (miRNAs) that are regulated by NANOG in TGCTs via integrated bioinformatic analyses of data from The Cancer Genome Atlas and NANOG chromatin immunoprecipitation in human embryonic stem cells. Through gain-of-function experiments, MIR9-2 was further investigated as a novel tumour suppressor regulated by NANOG. After transfection with MIR9-2 mimics, TGCT cells were analysed for cell proliferation, invasion, sensitivity to cisplatin, and gene expression signatures by RNA sequencing.

RESULTS

For the first time, we identified 86 miRNAs regulated by NANOG in TGCTs. Among these, 37 miRNAs were differentially expressed in NANOG-high tumours, and they clustered TGCTs according to their subtypes. Binding of NANOG within 2 kb upstream of the MIR9-2 locus was associated with a negative regulation. Low expression of MIR9-2 was associated with tumour progression and MIR9-2-5p was found to play a role in the control of tumour stemness. A gain of function of MIR9-2-5p was associated with reduced proliferation, invasion, and sensitivity to cisplatin in both embryonal carcinoma and seminoma tumours. MIR9-2-5p expression in TGCT cells significantly reduced the expression of genes regulating pluripotency and cell division, consistent with its functional effect on reducing cancer stemness.

CONCLUSIONS

This study provides new molecular insights into the role of NANOG as a key determinant of pluripotency in TGCTs through the regulation of MIR9-2-5p, a novel epigenetic modulator of cancer stemness. Our data also highlight the potential negative feedback mediated by MIR9-2-5p on NANOG expression, which could be exploited as a therapeutic strategy for the treatment of TGCTs.

Drug-resilient Cancer Cell Phenotype Is Acquired via Polyploidization Associated with Early Stress Response Coupled to HIF2α Transcriptional Regulation

Therapeutic resistance and recurrence remain core challenges in cancer therapy. How therapy resistance arises is currently not fully understood with tumors surviving via multiple alternative routes. Here, we demonstrate that a subset of cancer cells survives therapeutic stress by entering a transient state characterized by whole-genome doubling. At the onset of the polyploidization program, we identified an upregulation of key transcriptional regulators, including the early stress-response protein AP-1 and normoxic stabilization of HIF2α. We found altered chromatin accessibility, ablated expression of retinoblastoma protein (RB1), and enrichment of AP-1 motif accessibility. We demonstrate that AP-1 and HIF2α regulate a therapy resilient and survivor phenotype in cancer cells. Consistent with this, genetic or pharmacologic targeting of AP-1 and HIF2α reduced the number of surviving cells following chemotherapy treatment. The role of AP-1 and HIF2α in stress response by polyploidy suggests a novel avenue for tackling chemotherapy-induced resistance in cancer.

SIGNIFICANCE

In response to cisplatin treatment, some surviving cancer cells undergo whole-genome duplications without mitosis, which represents a mechanism of drug resistance. This study presents mechanistic data to implicate AP-1 and HIF2α signaling in the formation of this surviving cell phenotype. The results open a new avenue for targeting drug-resistant cells.

Classification of cancer cells at the sub-cellular level by phonon microscopy using deep learning

There is a consensus about the strong correlation between the elasticity of cells and tissue and their normal, dysplastic, and cancerous states. However, developments in cell mechanics have not seen significant progress in clinical applications. In this work, we explore the possibility of using phonon acoustics for this purpose. We used phonon microscopy to obtain a measure of the elastic properties between cancerous and normal breast cells. Utilising the raw time-resolved phonon-derived data (300 k individual inputs), we employed a deep learning technique to differentiate between MDA-MB-231 and MCF10a cell lines. We achieved a 93% accuracy using a single phonon measurement in a volume of approximately 2.5 μm3. We also investigated means for classification based on a physical model that suggest the presence of unidentified mechanical markers. We have successfully created a compact sensor design as a proof of principle, demonstrating its compatibility for use with needles and endoscopes, opening up exciting possibilities for future applications.

The impact of the COVID-19 pandemic on presentations of self-harm over an 18-month period to a tertiary hospital

OBJECTIVES

To examine and compare rates and methods of self-harm presenting to a tertiary referral hospital during an 18-month period since the onset of the COVID-19 pandemic with a similar period immediately prior to the pandemic onset.

METHODS

Data from an anonymized database compared rates of self-harm presentations and methods employed between 1st March 2020 and 31st August 2021 to a similar time-frame prior to the onset of the COVID-19 pandemic.

RESULTS

A 9.1% increase in presentations with self-harm was noted since the onset of the COVID-19 pandemic. Periods of more stringent restrictions were associated with higher levels of self-harm (daily rate of 2.10 v 0.77). A higher lethality of attempt was demonstrated post-COVID-19 onset (χ2 = 15.38, p < 0.001). Fewer individuals presenting with self-harm were diagnosed with an adjustment disorder since the onset of the COVID-19 pandemic (n = 84, 11.1%, v. n = 112, 16.2%, χ2 = 7.898, p = 0.005), with no other differences pertaining to psychiatric diagnosis noted. More patients actively engaged with mental health services (MHS) presented with self-harm (n = 239 (31.7%) v. n = 137, (19.8%), χ2 = 40.798, p ≤ 0.001) since the onset of the COVID-19 pandemic.

CONCLUSIONS

Despite an initial reduction, an increase in rates of self-harm has occurred since the onset of the COVID-19 pandemic with higher rates evident during periods of higher government mandated restrictions. An increase in active patients of MHS presenting with self-harm potentially relates to reduced availability of supports and particularly group activities. The recommencement of group therapeutic interventions for individuals attending MHS in particular is warranted.

The Role of miRNAs in Gliomas in Response to Hypoxia

AIMS

Identifying significant miRNAs that are either under or overexpressed in hypoxia compared to normoxia in glioma cells. Further exploring the effect and role of hypoxia on miR-92a-3p and miR-149-5p in gliomas in apoptotic and cellular senescence pathways.

METHOD

A range of glioma cells were used for screening, including primary cell lines: GIN28 and GIN31; low-grade cell lines: LGG19 and LGG24; a paediatric cell line: SF188 and a commercially available glioblastoma cell line U87. These cells were cultured at both 1% (hypoxia) and 20% (normoxia) oxygen levels. Screening of miRNAs was achieved by quantitative polymerase chain reaction (qPCR) using miRNA specific primers. Knockdowns/in were achieved by transfecting with miR-92a-3p and miR-149-5p mimics and inhibitors. Caspase-glo assay was used to assess the effect of hypoxia on apoptosis.

RESULTS

A range of miRNAs were differentially expressed in hypoxia in a range of glioma cell lines. miRNA 92a-3p and miR-149-5p were found to be downregulated and upregulated respectively in primary gliomablastoma cells in hypoxia compared to normoxia. These particular miRNAs are also found to have multiple targets in apoptosis and cellular senescence.

CONCLUSION

The screening of 90 miRNAs among the different categories of gliomas highlighted multiple miRNAs that were significant in hypoxia compared to normoxia. Using primary cell lines have identified hypoxia-affected miRNAs in glioblastomas. This discovery will increase our knowledge and understanding of the hypoxia effect on miRNAs which may aid and direct targeted therapy to conquer hypoxia in glioblastomas.

The impact of service user's suicide on mental health professionals

OBJECTIVES

Our principle objective was to examine the personal and professional impact of service user (SU) suicide on mental health professionals (MHPs). We also wished to explore putative demographic or clinical factors relating to SUs or MPHs that could influence the impact of SU suicide for MHPs and explore factors MHPs report as helpful in reducing distress following SU suicide.

METHODS

A mixed-method questionnaire with quantitative and thematic analysis was utilised.

RESULTS

Quantitative data indicated SU suicide was associated with personal and professional distress with sadness (79.5%), shock (74.5%) and surprise (68.7%) particularly evident with these phenomena lasting less than a year for more than 90% of MHPs. MHPs also reported guilt, reduced self-confidence and a fear of negative publicity. Thematic analysis indicated that some MHPs had greater expertise when addressing SU suicidal ideation and in supporting colleagues after experiencing a SU suicide. Only 17.7% of MHPs were offered formal support following SU suicide.

CONCLUSION

SU suicide impacts MHPs personally and professionally in both a positive and negative fashion. A culture and clear pathway of formal support for MHPs to ascertain the most appropriate individualised support dependent on the distress they experience following SU suicide would be optimal.

Targeting hypoxia regulated sodium driven bicarbonate transporters reduces triple negative breast cancer metastasis

Regions of low oxygen (hypoxia) are found in >50% of breast tumours, most frequently in the more aggressive triple negative breast cancer subtype (TNBC). Metastasis is the cause of 90% of breast cancer patient deaths. Regions of tumour hypoxia tend to be more acidic and both hypoxia and acidosis increase tumour metastasis. In line with this the metastatic process is dependent on pH regulatory mechanisms. We and others have previously identified increased hypoxic expression of Na+ driven bicarbonate transporters (NDBTs) as a major mechanism of tumour pH regulation. Hypoxia induced the expression of NDBTs in TNBC, most frequently SLC4A4 and SLC4A5. NDBT inhibition (S0859) and shRNA knockdown suppressed migration (40% reduction) and invasion (70% reduction) in vitro. Tumour xenograft metastasis in vivo was significantly reduced by NDBT knockdown. To investigate the mechanism by which NDBTs support metastasis, we investigated their role in regulation of phospho-signalling, epithelial-to-mesenchymal transition (EMT) and metabolism. NDBT knockdown resulted in an attenuation in hypoxic phospho-signalling activation; most notably LYN (Y397) reduced by 75%, and LCK (Y394) by 72%. The metastatic process is associated with EMT. We showed that NDBT knockdown inhibited EMT, modulating the expression of key EMT transcription factors and ablating the expression of vimentin whilst increasing the expression of E-cadherin. NDBT knockdown also altered metabolic activity reducing overall ATP and extracellular lactate levels. These results demonstrate that targeting hypoxia-induced NDBT can be used as an approach to modulate phospho-signalling, EMT, and metabolic activity and reduce tumour migration, invasion, and metastasis in vivo.

Endothelial Cell RNA-Seq Data: Differential Expression and Functional Enrichment Analyses to Study Phenotypic Switching

RNA-seq is a common approach used to explore gene expression data between experimental conditions or cell types and ultimately leads to information that can shed light on the biological processes involved and inform further hypotheses. While the protocols required to generate samples for sequencing can be performed in most research facilities, the resulting computational analysis is often an area in which researchers have little experience. Here we present a user-friendly bioinformatics workflow which describes the methods required to take raw data produced by RNA sequencing to interpretable results. Widely used and well documented tools are applied. Data quality assessment and read trimming were performed by FastQC and Cutadapt, respectively. Following this, STAR was utilized to map the trimmed reads to a reference genome and the alignment was analyzed by Qualimap. The subsequent mapped reads were quantified by featureCounts. DESeq2 was used to normalize and perform differential expression analysis on the quantified reads, identifying differentially expressed genes and preparing the data for functional enrichment analysis. Gene set enrichment analysis identified enriched gene sets from the normalized count data and clusterProfiler was used to perform functional enrichment against the GO, KEGG, and Reactome databases. Example figures of the functional enrichment analysis results were also generated. The example data used in the workflow are derived from HUVECs, an in vitro model used in the study of endothelial cells, published and publicly available for download from the European Nucleotide Archive.

Doxycycline Attenuates Cancer Cell Growth by Suppressing NLRP3-Mediated Inflammation

NLR family pyrin domain containing 3 (NLRP3) inflammasome formation is triggered by the damaged mitochondria releasing reactive oxygen species. Doxycycline was shown to regulate inflammation; however, its effect on NLRP3 in cancer remains largely unknown. Therefore, we sought to determine the effect of doxycycline on NLRP3 regulation in cancer using an in vitro model. NLRP3 was activated in a prostate cancer cell line (PC3) and a lung cancer cell line (A549) before treatment with doxycycline. Inflammasome activation was assessed by analyzing RNA expression of NLRP3, Pro-CASP-1, and Pro-IL1β using RT-qPCR. Additionally, NLPR3 protein expression and IL-1β secretion were analyzed using Western blot and ELISA, respectively. Tumor cell viability was determined using Annexin V staining and a cell proliferation assay. Cytokine secretion was analyzed using a 41Plex assay for human cytokines. Data were analyzed using one-way ANOVA model with Tukey’s post hoc tests. Doxycycline treatment decreased NLRP3 formation in PC3 and A549 cells compared to untreated and LPS only treated cells (p < 0.05). Doxycycline also decreased proliferation and caused cell death through apoptosis, a response that differed to the LPS-Nigericin mediated pyroptosis. Our findings suggest that doxycycline inhibits LPS priming of NLRP3 and reduces tumor progression through early apoptosis in cancer.

Therapeutic Potential of Pharmacological Targeting NLRP3 Inflammasome Complex in Cancer

Introduction

Dysregulation of NLRP3 inflammasome complex formation can promote chronic inflammation by increased release of IL-1β. However, the effect of NLRP3 complex formation on tumor progression remains controversial. Therefore, we sought to determine the effect of NLRP3 modulation on the growth of the different types of cancer cells, derived from lung, breast, and prostate cancers as well as neuroblastoma and glioblastoma in-vitro.

Method

The effect of Caspase 1 inhibitor (VX765) and combination of LPS/Nigericin on NLRP3 inflammasome activity was analyzed in A549 (lung cancer), MCF-7 (breast cancer), PC3 (prostate cancer), SH-SY5Y (neuroblastoma), and U138MG (glioblastoma) cells. Human fibroblasts were used as control cells. The effect of VX765 and LPS/Nigericin on NLRP3 expression was analyzed using western blot, while IL-1β and IL-18 secretion was detected by ELISA. Tumor cell viability and progression were determined using Annexin V, cell proliferation assay, LDH assay, sphere formation assay, transmission electron microscopy, and a multiplex cytokine assay. Also, angiogenesis was investigated by a tube formation assay. VEGF and MMPs secretion were detected by ELISA and a multiplex assay, respectively. Statistical analysis was done using one-way ANOVA with Tukey’s analyses and Kruskal–Wallis one-way analysis of variance.

Results

LPS/Nigericin increased NRLP3 protein expression as well as IL-1β and IL-18 secretion in PC3 and U138MG cells compared to A549, MCF7, SH-SY5Y cells, and fibroblasts. In contrast, MIF expression was commonly found upregulated in A549, PC3, SH-SY5Y, and U138MG cells and fibroblasts after Nigericin treatment. Nigericin and a combination of LPS/Nigericin decreased the cell viability and proliferation. Also, LPS/Nigericin significantly increased tumorsphere size in PC3 and U138MG cells. In contrast, the sphere size was reduced in MCF7 and SH-SY5Y cells treated with LPS/Nigericin, while no effect was detected in A549 cells. VX765 increased secretion of CCL24 in A549, MCF7, PC3, and fibroblasts as well as CCL11 and CCL26 in SH-SY5Y cells. Also, VX765 significantly increased the production of VEGF and MMPs and stimulated angiogenesis in all tumor cell lines.

Discussion

Our data suggest that NLRP3 activation using Nigericin could be a novel therapeutic approach to control the growth of tumors producing a low level of IL-1β and IL-18.

Regulation of cellular sterol homeostasis by the oxygen responsive noncoding RNA lincNORS

We hereby provide the initial portrait of lincNORS, a spliced lincRNA generated by the MIR193BHG locus, entirely distinct from the previously described miR-193b-365a tandem. While inducible by low O₂ in a variety of cells and associated with hypoxia in vivo, our studies show that lincNORS is subject to multiple regulatory inputs, including estrogen signals. Biochemically, this lincRNA fine-tunes cellular sterol/steroid biosynthesis by repressing the expression of multiple pathway components. Mechanistically, the function of lincNORS requires the presence of RALY, an RNA-binding protein recently found to be implicated in cholesterol homeostasis. We also noticed the proximity between this locus and naturally occurring genetic variations highly significant for sterol/steroid-related phenotypes, in particular the age of sexual maturation. An integrative analysis of these variants provided a more formal link between these phenotypes and lincNORS, further strengthening the case for its biological relevance.

Abstract 2652: Defining the role of AP1 in molecular adaptation to hypoxia in colorectal cancer

Background:

The aim of this project was to investigate the role of Activator Protein 1 (AP1) in molecular adaptation to hypoxia in colorectal cancer. Colorectal cancer is the 3rd most common cancer worldwide. Low oxygen (hypoxia) found in 30-50% of colorectal tumors is associated with resistance to chemotherapy, radiotherapy and poor patient prognosis. Hypoxia stabilizes the transcription factors HIF1α and HIF2α which enable molecular adaptation to the hypoxic insult at a transcriptional level, in cooperation with additional transcription factors. To identify genes that regulate hypoxic survival in colorectal cancer, we carried out a lentiviral shRNA unbiased screen targeting 6142 genes, in HCT116 cells. We identified AP1 transcription factor subunits as key mediators of hypoxic cell viability that were required in hypoxia and in 3D spheroid culture in colorectal cancer

Methods: Our experiments were conducted in a panel of cancer and normal colorectal cell lines (HCT116, LS174T, SW620, HT29 and CCD 841 CoN) in normoxia and hypoxia (1%O2) and in 3D spheroid cultures. The association of the different AP1 subunits and the impact of AP1 subunits on hypoxia-regulated expression and cell phenotypes was investigated using a variety of cell and molecular biology approaches.

Results: Our results identify that AP1 subunits cJUN, JUNB, JUND, FOSL1 and FOSL2 are upregulated by hypoxia in colorectal cancer in a HIF independent manner. We observed that individual AP1 subunit knockdown in particular FOSL2 and JUND knockdown significantly decreased cancer cell survival in hypoxia. FOSL2 and JUND decreased the cell survival respectively by 40% and 60% in HCT116 and by 45% and 60% in LS174T (n=3, p&lt;0.001). This effect was not observed when the cells were treated with T-5224 (10 µM), an AP-1 inhibitor suggesting a complex modulation of the transcriptional response by AP1 in hypoxia. In hypoxic conditions, by Co-IP studies, we established in HCT116 and LS174T that a selected pattern of AP1 heterodimers in particular FOSL2/JUNB and FOSL2/cJUN heterodimers were induced to mediate the transcriptional response to hypoxia. siRNA knockdown demonstrated that AP1 subunits modulate the expression of a specific set of hypoxia-regulated genes such as CA9 (Carbonic Anhydrase 9) and ANGPTL4 (n=3, p&lt;0.05), important modulators of the hypoxic response.

Conclusions:

These data identify AP1 as a key mediator of the molecular adaptation to the hypoxic insult in the colorectal tumour microenvironment. Targeting AP1 subunits is a likely therapeutic approach for the treatment of the therapy resistant hypoxic regions of colorectal cancers.

Citation Format: Eric Vancauwenberghe, Hannah Bolland, Christopher Carroll, Leonardo Da Motta, Anna Grabowska, Francesca Buffa, Adrian Harris, Alan McIntyre. Defining the role of AP1 in molecular adaptation to hypoxia in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2652.

Adaptation to HIF1α Deletion in Hypoxic Cancer Cells by Upregulation of GLUT14 and Creatine Metabolism

Hypoxia-inducible factor 1α is a key regulator of the hypoxia response in normal and cancer tissues. It is well recognized to regulate glycolysis and is a target for therapy. However, how tumor cells adapt to grow in the absence of HIF1α is poorly understood and an important concept to understand for developing targeted therapies is the flexibility of the metabolic response to hypoxia via alternative pathways. We analyzed pathways that allow cells to survive hypoxic stress in the absence of HIF1α, using the HCT116 colon cancer cell line with deleted HIF1α versus control. Spheroids were used to provide a 3D model of metabolic gradients. We conducted a metabolomic, transcriptomic, and proteomic analysis and integrated the results. These showed surprisingly that in three-dimensional growth, a key regulatory step of glycolysis is Aldolase A rather than phosphofructokinase. Furthermore, glucose uptake could be maintained in hypoxia through upregulation of GLUT14, not previously recognized in this role. Finally, there was a marked adaptation and change of phosphocreatine energy pathways, which made the cells susceptible to inhibition of creatine metabolism in hypoxic conditions. Overall, our studies show a complex adaptation to hypoxia that can bypass HIF1α, but it is targetable and it provides new insight into the key metabolic pathways involved in cancer growth. IMPLICATIONS: Under hypoxia and HIF1 blockade, cancer cells adapt their energy metabolism via upregulation of the GLUT14 glucose transporter and creatine metabolism providing new avenues for drug targeting.

Hypoxia-induced switch in SNAT2/SLC38A2 regulation generates endocrine resistance in breast cancer

Tumor hypoxia is associated with poor patient outcomes in estrogen receptor-α-positive (ERα+) breast cancer. Hypoxia is known to affect tumor growth by reprogramming metabolism and regulating amino acid (AA) uptake. Here, we show that the glutamine transporter, SNAT2, is the AA transporter most frequently induced by hypoxia in breast cancer, and is regulated by hypoxia both in vitro and in vivo in xenografts. SNAT2 induction in MCF7 cells was also regulated by ERα, but it became predominantly a hypoxia-inducible factor 1α (HIF-1α)-dependent gene under hypoxia. Relevant to this, binding sites for both HIF-1α and ERα overlap in SNAT2's cis-regulatory elements. In addition, the down-regulation of SNAT2 by the ER antagonist fulvestrant was reverted in hypoxia. Overexpression of SNAT2 in vitro to recapitulate the levels induced by hypoxia caused enhanced growth, particularly after ERα inhibition, in hypoxia, or when glutamine levels were low. SNAT2 up-regulation in vivo caused complete resistance to antiestrogen and, partially, anti-VEGF therapies. Finally, high SNAT2 expression levels correlated with hypoxia profiles and worse outcome in patients given antiestrogen therapies. Our findings show a switch in the regulation of SNAT2 between ERα and HIF-1α, leading to endocrine resistance in hypoxia. Development of drugs targeting SNAT2 may be of value for a subset of hormone-resistant breast cancer.

MicroRNA Post-transcriptional Regulation of the NLRP3 Inflammasome in Immunopathologies

Inflammation has a crucial role in protection against various pathogens. The inflammasome is an intracellular multiprotein signaling complex that is linked to pathogen sensing and initiation of the inflammatory response in physiological and pathological conditions. The most characterized inflammasome is the NLRP3 inflammasome, which is a known sensor of cell stress and is tightly regulated in resting cells. However, altered regulation of the NLRP3 inflammasome is found in several pathological conditions, including autoimmune disease and cancer. NLRP3 expression was shown to be post-transcriptionally regulated and multiple miRNA have been implicated in post-transcriptional regulation of the inflammasome. Therefore, in recent years, miRNA based post-transcriptional control of NLRP3 has become a focus of much research, especially as a potential therapeutic approach. In this review, we provide a summary of the recent investigations on the role of miRNA in the post-transcriptional control of the NLRP3 inflammasome, a key regulator of pro-inflammatory IL-1β and IL-18 cytokine production. Current approaches to targeting the inflammasome product were shown to be an effective treatment for diseases linked to NLRP3 overexpression. Although utilizing NLRP3 targeting miRNAs was shown to be a successful therapeutic approach in several animal models, their therapeutic application in patients remains to be determined.

Effects of acute sleep deprivation and caffeine supplementation on anaerobic performance

Purpose

Athletes involved in team sports may be subject to varying degrees of sleep deprivation either before or after training and competition. Despite the belief among athletes and coaches of the importance of adequate sleep for ensuing performance, the effect of sleep loss on team-sport anaerobic performance remains unclear. There is conflicting evidence in the scientific literature as to the impact of acute sleep deprivation and caffeine supplementation on anaerobic performance indices. The purpose of this study is to investigate the effect of 24 hours of acute sleep deprivation on anaerobic performance and the effect of caffeine supplementation on anaerobic performance in the sleep deprived state.

Methods

11 club level games players (n=11, 25±4 yr, 178±7.5 cm, 80.2±10.4 kg, 15.1±5.6% body fat) participated in a repeated measures double-blinded placebo control trial. Following familiarisation, each participant returned for testing on three separate occasions. One of the testing sessions took place following a night of normal sleep and the other two sessions took place following 24 hours of sleep deprivation with supplementation of either placebo or 6 mg.kg- 1 of caffeine. During each testing session participants performed the vertical jump height, 20-m straight sprint, Illinois speed agility test and 5-m shuttle run.

Results

No significant differences were detected comparing non sleep deprived and sleep deprived interventions in any of the assessed outcome measures. There were also no significant differences observed in any of the outcome measures when comparing caffeine and placebo data in the sleep deprived state.

Conclusion

In this cohort of athletes, a 24-h period of acute sleep deprivation did not have any significant impact on anaerobic performance. Caffeine also did not have any effect of on anaerobic performance in the sleep-deprived state.

IGF1R signalling in testicular germ cell tumour cells impacts on cell survival and acquired cisplatin resistance

Testicular germ cell tumours (TGCTs) are the most frequent malignancy and cause of death from solid tumours in the 20‐ to 40‐year age group. Although most cases show sensitivity to cis‐platinum‐based chemotherapy, this is associated with long‐term toxicities and chemo‐resistance. Roles for receptor tyrosine kinases other than KIT are largely unknown in TGCT. We therefore conducted a phosphoproteomic screen and identified the insulin growth factor receptor‐1 (IGF1R) as both highly expressed and activated in TGCT cell lines representing the nonseminomatous subtype. IGF1R was also frequently expressed in tumour samples from patients with nonseminomas. Functional analysis of cell line models showed that long‐term shRNA‐mediated IGF1R silencing leads to apoptosis and complete ablation of nonseminoma cells with active IGF1R signalling. Cell lines with high levels of IGF1R activity also showed reduced AKT signalling in response to decreased IGF1R expression as well as sensitivity to the small‐molecule IGF1R inhibitor NVP‐AEW541. These results were in contrast to those in the seminoma cell line TCAM2 that lacked IGF1R signalling via AKT and was one of the two cell lines least sensitive to the IGF1R inhibitor. The dependence on IGF1R activity in the majority of nonseminomas parallels the known role of IGF signalling in the proliferation, migration, and survival of primordial germ cells, the putative cell of origin for TGCT. Upregulation of IGF1R expression and signalling was also found to contribute to acquired cisplatin resistance in an in vitro nonseminoma model, providing a rationale for targeting IGF1R in cisplatin‐resistant disease. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Methods: Using Three-Dimensional Culture (Spheroids) as an In Vitro Model of Tumour Hypoxia

Regions of hypoxia in tumours can be modelled in vitro in 2D cell cultures with a hypoxic chamber or incubator in which oxygen levels can be regulated. Although this system is useful in many respects, it disregards the additional physiological gradients of the hypoxic microenvironment, which result in reduced nutrients and more acidic pH. Another approach to hypoxia modelling is to use three-dimensional spheroid cultures. In spheroids, the physiological gradients of the hypoxic tumour microenvironment can be inexpensively modelled and explored. In addition, spheroids offer the advantage of more representative modelling of tumour therapy responses compared with 2D culture. Here, we review the use of spheroids in hypoxia tumour biology research and highlight the different methodologies for spheroid formation and how to obtain uniformity. We explore the challenge of spheroid analyses and how to determine the effect on the hypoxic versus normoxic components of spheroids. We discuss the use of high-throughput analyses in hypoxia screening of spheroids. Furthermore, we examine the use of mathematical modelling of spheroids to understand more fully the hypoxic tumour microenvironment.

An aerosol challenge model of tuberculosis in Mauritian cynomolgus macaques

Background

New interventions for tuberculosis are urgently needed. Non-human primate (NHP) models provide the most relevant pre-clinical models of human disease and play a critical role in vaccine development. Models utilising Asian cynomolgus macaque populations are well established but the restricted genetic diversity of the Mauritian cynomolgus macaques may be of added value.

Methods

Mauritian cynomolgus macaques were exposed to a range of doses of M. tuberculosis delivered by aerosol, and the outcome was assessed using clinical, imaging and pathology-based measures.

Results

All macaques developed characteristic clinical signs and disease features of tuberculosis (TB). Disease burden and the ability to control disease were dependent on exposure dose. Mauritian cynomolgus macaques showed less variation in pulmonary disease burden and total gross pathology scores within exposure dose groups than either Indian rhesus macaques or Chinese cynomolgus macaques

Conclusions

The genetic homogeneity of Mauritian cynomolgus macaques makes them a potentially useful model of human tuberculosis.

The Role of pH Regulation in Cancer Progression

Frequently observed phenotypes of tumours include high metabolic activity, hypoxia and poor perfusion; these act to produce an acidic microenvironment. Cellular function depends on pH homoeostasis, and thus, tumours become dependent on pH regulatory mechanisms. Many of the proteins involved in pH regulation are highly expressed in tumours, and their expression is often of prognostic significance. The more acidic tumour microenvironment also has important implications with regard to chemotherapeutic and radiotherapeutic interventions. In addition, we review pH-sensing mechanisms, the role of pH regulation in tumour phenotype and the use of pH regulatory mechanisms as therapeutic targets.

The BET inhibitor JQ1 selectively impairs tumour response to hypoxia and downregulates CA9 and angiogenesis in triple negative breast cancer

The availability of bromodomain and extra-terminal inhibitors (BETi) has enabled translational epigenetic studies in cancer. BET proteins regulate transcription by selectively recognizing acetylated lysine residues on chromatin. BETi compete with this process leading to both downregulation and upregulation of gene expression. Hypoxia enables progression of triple negative breast cancer (TNBC), the most aggressive form of breast cancer, partly by driving metabolic adaptation, angiogenesis and metastasis through upregulation of hypoxia-regulated genes (for example, carbonic anhydrase 9 (CA9) and vascular endothelial growth factor A (VEGF-A). Responses to hypoxia can be mediated epigenetically, thus we investigated whether BETi JQ1 could impair the TNBC response induced by hypoxia and exert anti-tumour effects. JQ1 significantly modulated 44% of hypoxia-induced genes, of which two-thirds were downregulated including CA9 and VEGF-A. JQ1 prevented HIF binding to the hypoxia response element in CA9 promoter, but did not alter HIF expression or activity, suggesting some HIF targets are BET-dependent. JQ1 reduced TNBC growth in vitro and in vivo and inhibited xenograft vascularization. These findings identify that BETi dually targets angiogenesis and the hypoxic response, an effective combination at reducing tumour growth in preclinical studies.

Alternative BCG delivery strategies improve protection against Mycobacterium tuberculosis in non-human primates: Protection associated with mycobacterial antigen-specific CD4 effector memory T-cell populations

Intradermal (ID) BCG injection provides incomplete protection against TB in humans and experimental models. Alternative BCG vaccination strategies may improve protection in model species, including rhesus macaques. This study compares the immunogenicity and efficacy of BCG administered by ID and intravenous (IV) injection, or as an intratracheal mucosal boost (ID + IT), against aerosol challenge with Mycobacterium tuberculosis Erdman strain. Disease pathology was significantly reduced, and survival improved, by each BCG vaccination strategy, relative to unvaccinated animals. However, IV induced protection surpassed that achieved by all other routes, providing an opportunity to explore protective immunological mechanisms using antigen-specific IFN-γ ELISpot and polychromatic flow cytometry assays. IFN-γ spot forming units and multifunctional CD4 T-cell frequencies increased significantly following each vaccination regimen and were greatest following IV immunisation. Vaccine-induced multifunctional CD4 T-cells producing IFN-γ and TNF-α were associated with reduced disease pathology following subsequent M.tb challenge; however, high frequencies of this population following M.tb infection correlated with increased pathology. Cytokine producing T-cells primarily occupied the CD4 transitional effector memory phenotype, implicating this population as central to the mycobacterial response, potentially contributing to the stringent control observed in IV vaccinated animals. This study demonstrates the protective efficacy of IV BCG vaccination in rhesus macaques, offering a valuable tool for the interrogation of immunological mechanisms and potential correlates of protection.

Disrupting Hypoxia-Induced Bicarbonate Transport Acidifies Tumor Cells and Suppresses Tumor Growth

Tumor hypoxia is associated clinically with therapeutic resistance and poor patient outcomes. One feature of tumor hypoxia is activated expression of carbonic anhydrase IX (CA9), a regulator of pH and tumor growth. In this study, we investigated the hypothesis that impeding the reuptake of bicarbonate produced extracellularly by CA9 could exacerbate the intracellular acidity produced by hypoxic conditions, perhaps compromising cell growth and viability as a result. In 8 of 10 cancer cell lines, we found that hypoxia induced the expression of at least one bicarbonate transporter. The most robust and frequent inductions were of the sodium-driven bicarbonate transporters SLC4A4 and SLC4A9, which rely upon both HIF1α and HIF2α activity for their expression. In cancer cell spheroids, SLC4A4 or SLC4A9 disruption by either genetic or pharmaceutical approaches acidified intracellular pH and reduced cell growth. Furthermore, treatment of spheroids with S0859, a small-molecule inhibitor of sodium-driven bicarbonate transporters, increased apoptosis in the cell lines tested. Finally, RNAi-mediated attenuation of SLC4A9 increased apoptosis in MDA-MB-231 breast cancer spheroids and dramatically reduced growth of MDA-MB-231 breast tumors or U87 gliomas in murine xenografts. Our findings suggest that disrupting pH homeostasis by blocking bicarbonate import might broadly relieve the common resistance of hypoxic tumors to anticancer therapy. Cancer Res; 76(13); 3744-55. ©2016 AACR.

Genomic alterations underlie a pan-cancer metabolic shift associated with tumour hypoxia

BACKGROUND

Altered metabolism is a hallmark of cancer. However, the role of genomic changes in metabolic genes driving the tumour metabolic shift remains to be elucidated. Here, we have investigated the genomic and transcriptomic changes underlying this shift across ten different cancer types.

RESULTS

A systematic pan-cancer analysis of 6538 tumour/normal samples covering ten major cancer types identified a core metabolic signature of 44 genes that exhibit high frequency somatic copy number gains/amplifications (>20 % cases) associated with increased mRNA expression (ρ > 0.3, q < 10(-3)). Prognostic classifiers using these genes were confirmed in independent datasets for breast and kidney cancers. Interestingly, this signature is strongly associated with hypoxia, with nine out of ten cancer types showing increased expression and five out of ten cancer types showing increased gain/amplification of these genes in hypoxic tumours (P ≤ 0.01). Further validation in breast and colorectal cancer cell lines highlighted squalene epoxidase, an oxygen-requiring enzyme in cholesterol biosynthesis, as a driver of dysregulated metabolism and a key player in maintaining cell survival under hypoxia.

CONCLUSIONS

This study reveals somatic genomic alterations underlying a pan-cancer metabolic shift and suggests genomic adaptation of these genes as a survival mechanism in hypoxic tumours.

A meta-review of stress, coping and interventions in dementia and dementia caregiving

Background

There has been a substantial number of systematic reviews of stress, coping and interventions for people with dementia and their caregivers. This paper provides a meta-review of this literature 1988-2014.

Method

A meta-review was carried out of systematic reviews of stress, coping and interventions for people with dementia and their caregivers, using SCOPUS, Google Scholar and CINAHL Plus databases and manual searches.

Results

The meta-review identified 45 systematic reviews, of which 15 were meta-analyses. Thirty one reviews addressed the effects of interventions and 14 addressed the results of correlational studies of factors associated with stress and coping. Of the 31 systematic reviews dealing with intervention studies, 22 focused on caregivers, 6 focused on people with dementia and 3 addressed both groups. Overall, benefits in terms of psychological measures of mental health and depression were generally found for the use of problem focused coping strategies and acceptance and social-emotional support coping strategies. Poor outcomes were associated with wishful thinking, denial, and avoidance coping strategies. The interventions addressed in the systematic reviews were extremely varied and encompassed Psychosocial, Psychoeducational, Technical, Therapy, Support Groups and Multicomponent interventions. Specific outcome measures used in the primary sources covered by the systematic reviews were also extremely varied but could be grouped into three dimensions, viz., a broad dimension of “Psychological Well-Being v. Psychological Morbidity” and two narrower dimensions of “Knowledge and Coping” and of “Institutionalisation Delay”.

Conclusions

This meta-review supports the conclusion that being a caregiver for people with dementia is associated with psychological stress and physical ill-health. Benefits in terms of mental health and depression were generally found for caregiver coping strategies involving problem focus, acceptance and social-emotional support. Negative outcomes for caregivers were associated with wishful thinking, denial and avoidance coping strategies. Psychosocial and Psychoeducational interventions were beneficial for caregivers and for people with dementia. Support groups, Multicomponent interventions and Joint Engagements by both caregivers and people with dementia were generally found to be beneficial. It was notable that virtually all reviews addressed very general coping strategies for stress broadly considered, rather than in terms of specific remedies for specific sources of stress. Investigation of specific stressors and remedies would seem to be a useful area for future research.

Electronic supplementary material

The online version of this article (doi:10.1186/s12877-016-0280-8) contains supplementary material, which is available to authorized users.

The Role of Oxygen in Avascular Tumor Growth

The oxygen status of a tumor has significant clinical implications for treatment prognosis, with well-oxygenated subvolumes responding markedly better to radiotherapy than poorly supplied regions. Oxygen is essential for tumor growth, yet estimation of local oxygen distribution can be difficult to ascertain in situ, due to chaotic patterns of vasculature. It is possible to avoid this confounding influence by using avascular tumor models, such as tumor spheroids, a much better approximation of realistic tumor dynamics than monolayers, where oxygen supply can be described by diffusion alone. Similar to in situ tumours, spheroids exhibit an approximately sigmoidal growth curve, often approximated and fitted by logistic and Gompertzian sigmoid functions. These describe the basic rate of growth well, but do not offer an explicitly mechanistic explanation. This work examines the oxygen dynamics of spheroids and demonstrates that this growth can be derived mechanistically with cellular doubling time and oxygen consumption rate (OCR) being key parameters. The model is fitted to growth curves for a range of cell lines and derived values of OCR are validated using clinical measurement. Finally, we illustrate how changes in OCR due to gemcitabine treatment can be directly inferred using this model.

The tumour hypoxia induced non-coding transcriptome

Recent investigations have highlighted the importance of the non-coding genome in regions of hypoxia in tumours. Such regions are frequently found in solid tumours, and are associated with worse patient survival and therapy resistance. Hypoxia stabilises the transcription factors, hypoxia inducible factors (HIF1α and HIF2α) which coordinate transcriptomic changes that occur in hypoxia. The changes in gene expression induced by HIF1α and HIF2α contribute to many of the hallmarks of cancer phenotypes and enable tumour growth, survival and invasion in the hypoxic tumour microenvironment. Non-coding RNAs, in particular microRNAs (miRNAs), which regulate mRNA stability and translation, and long-non-coding RNAs (lncRNAs), which have diverse functions including chromatin modification and transcriptional regulation, are also important in enabling the key hypoxia regulated processes. They have roles in the regulation of metabolism, angiogenesis, autophagy, invasion and metastasis in the hypoxic microenvironment. Furthermore, HIF1α and HIF2α expression and stabilisation are also regulated by both miRNAs and lncRNAs. Here we review the recent developments in the expression, regulation and functions of miRNAs, lncRNAs and other non-coding RNA classes in tumour hypoxia.

Carbonic Anhydrase Activity Monitored In Vivo by Hyperpolarized 13C-Magnetic Resonance Spectroscopy Demonstrates Its Importance for pH Regulation in Tumors

Carbonic anhydrase buffers tissue pH by catalyzing the rapid interconversion of carbon dioxide (CO2) and bicarbonate (HCO3 (-)). We assessed the functional activity of CAIX in two colorectal tumor models, expressing different levels of the enzyme, by measuring the rate of exchange of hyperpolarized (13)C label between bicarbonate (H(13)CO3(-)) and carbon dioxide ((13)CO2), following injection of hyperpolarized H(13)CO3(-), using (13)C-magnetic resonance spectroscopy ((13)C-MRS) magnetization transfer measurements. (31)P-MRS measurements of the chemical shift of the pH probe, 3-aminopropylphosphonate, and (13)C-MRS measurements of the H(13)CO3(-)/(13)CO2 peak intensity ratio showed that CAIX overexpression lowered extracellular pH in these tumors. However, the (13)C measurements overestimated pH due to incomplete equilibration of the hyperpolarized (13)C label between the H(13)CO3(-) and (13)CO2 pools. Paradoxically, tumors overexpressing CAIX showed lower enzyme activity using magnetization transfer measurements, which can be explained by the more acidic extracellular pH in these tumors and the decreased activity of the enzyme at low pH. This explanation was confirmed by administration of bicarbonate in the drinking water, which elevated tumor extracellular pH and restored enzyme activity to control levels. These results suggest that CAIX expression is increased in hypoxia to compensate for the decrease in its activity produced by a low extracellular pH and supports the hypothesis that a major function of CAIX is to lower the extracellular pH.

Carbonic anhydrase IX induction defines a heterogeneous cancer cell response to hypoxia and mediates stem cell-like properties and sensitivity to HDAC inhibition

Carbonic anhydrase IX (CAIX) is strongly induced by hypoxia and its overexpression is associated with poor therapeutic outcome in cancer. Here, we report that hypoxia promotes tumour heterogeneity through the epigenetic regulation of CAIX. Based on hypoxic CAIX expression we identify and characterize two distinct populations of tumour cells, one that has inducible expression of CAIX and one that does not. The CAIX+ve population is enriched with cells expressing cancer stem cell markers and which have high self-renewal capacity. We show that differential CAIX expression is due to differences in chromatin structure. To further investigate the relationship between chromatin organization and hypoxic induction of CAIX expression we investigated the effect of JQ1 an inhibitor of BET bromodomain proteins and A366 a selective inhibitor of the H3K9 methyltransferase G9a/GLP. We identified that these drugs were able to modulate hypoxic CAIX expression induction. This further highlights the role of epigenetic modification in adaption to hypoxia and also in regulation of heterogeneity of cells within tumours. Interestingly, we identified that the two subpopulations show a differential sensitivity to HDAC inhibitors, NaBu or SAHA, with the CAIX positive showing greater sensitivity to treatment. We propose that drugs modulating chromatin regulation of expression may be used to reduce heterogeneity induced by hypoxia and could in combination have significant clinical consequences.

The pH low insertion peptide pHLIP Variant 3 as a novel marker of acidic malignant lesions

Current strategies for early detection of breast and other cancers are limited in part because some lesions identified as potentially malignant do not develop into aggressive tumors. Acid pH has been suggested as a key characteristic of aggressive tumors that might distinguish aggressive lesions from more indolent pathology. We therefore investigated the novel class of molecules, pH low insertion peptides (pHLIPs), as markers of low pH in tumor allografts and of malignant lesions in a mouse model of spontaneous breast cancer, BALB/neu-T. pHLIP Variant 3 (Var3) conjugated with fluorescent Alexa546 was shown to insert into tumor spheroids in a sequence-specific manner. Its signal reflected pH in murine tumors. It was induced by carbonic anhydrase IX (CAIX) overexpression and inhibited by acetazolamide (AZA) administration. By using (31)P magnetic resonance spectroscopy (MRS), we demonstrated that pHLIP Var3 was retained in tumors of pH equal to or less than 6.7 but not in tissues of higher pH. In BALB/neu-T mice at different stages of the disease, the fluorescent signal from pHLIP Var3 marked cancerous lesions with a very low false-positive rate. However, only ∼60% of the smallest lesions retained a pHLIP Var3 signal, suggesting heterogeneity in pH. Taken together, these results show that pHLIP can identify regions of lower pH, allowing for its development as a theranostic tool for clinical applications.

Abstract 3750: Genomic alterations underlie a pan-cancer metabolic transcriptome shift

Background

Hypoxia is a key physiological and microenvironmental difference between tumour and normal tissues. Hypoxia induces DNA damage, genomic aberrations and reprogramming of DNA repair mechanisms. A crucial mechanism in a highly dynamic hypoxic tumour microenvironment is metabolic reprogramming of tumour cells. Genome-wide multi-modal molecular profiles have been generated, however it remains unclear whether upregulation of metabolic genes is substantially enriched with somatically acquired alterations. To answer this, we performed a pan-cancer integrative analysis of genomic and transcriptomic profiles of 10 TCGA tumour types (n = 5,500).

Methods

2,750 metabolic genes were extracted from KEGG pathways, and differentially upregulated genes were identified for each tumour type. High-ranking (10%) upregulated genes were assessed for correlation between mRNA abundance and DNA copy-number changes, and subsequently tested for metabolic-enrichment using genome-wide permutation analysis. For each tumour type, highly correlated genesets were subsequently examined for their potential as drug targets and biomarkers of disease relapse.

Results

Integrative analysis of mRNA and copy-number data revealed clusters of tumours that exhibit similar landscape of metabolic gene profiles, and those having unique metabolic copy number aberrations. Within these profiles, we identify a core set of genes that exhibit strong correlation (Spearman's ρ&gt;0.3; q&lt;0.001) between DNA and RNA profiles (candidate drivers) across a range of tumour types. Compared to genome-wide correlation patterns, the correlated genes were significantly over-represented in breast, glioblastoma multiforme and ovarian cancers (p&lt;0.05). Of note, the correlation analysis uncovered breast cancer subtype-specific heterogeneity in altered metabolic profiles with aggressive breast cancers (Basal and HER2-enriched) demonstrating higher number of candidate drivers. mRNA correlation analysis performed on the top candidate drivers revealed an overall trend of positive correlation between hypoxia signature and metabolic genes. This highlights hypoxia as a potential cause of metabolic dysregulation. Further in-vitro analysis of one of the top candidate drivers, SQLE amplification, showed a marked sensitivity to inhibition in hypoxia compared to normoxia, highlighting hypoxia dependence of genetic and metabolic reprograming in aggressive breast cancers (Basal and HER2-enriched) and colon cancer.

Conclusions

We isolate tumour-type specific and core pan-cancer metabolic gene signatures revealing within and cross disease heterogeneity in metabolic profiles. We highlight a core set of pan-cancer metabolic candidate drivers which are recurrently over-expressed due to genomic amplifications induced by hypoxia.

Citation Format: Syed Haider, Alan McIntyre, Ruud GPM van Stiphout, Laura M. Winchester, Simon Wigfield, Adrian L. Harris, Francesca M. Buffa. Genomic alterations underlie a pan-cancer metabolic transcriptome shift. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3750. doi:10.1158/1538-7445.AM2015-3750

Metabolic and hypoxic adaptation to anti-angiogenic therapy: a target for induced essentiality

Anti-angiogenic therapy has increased the progression-free survival of many cancer patients but has had little effect on overall survival, even in colon cancer (average 6-8 weeks) due to resistance. The current licensed targeted therapies all inhibit VEGF signalling (Table 1). Many mechanisms of resistance to anti-VEGF therapy have been identified that enable cancers to bypass the angiogenic blockade. In addition, over the last decade, there has been increasing evidence for the role that the hypoxic and metabolic responses play in tumour adaptation to anti-angiogenic therapy. The hypoxic tumour response, through the transcription factor hypoxia-inducible factors (HIFs), induces major gene expression, metabolic and phenotypic changes, including increased invasion and metastasis. Pre-clinical studies combining anti-angiogenics with inhibitors of tumour hypoxic and metabolic adaptation have shown great promise, and combination clinical trials have been instigated. Understanding individual patient response and the response timing, given the opposing effects of vascular normalisation versus reduced perfusion seen with anti-angiogenics, provides a further hurdle in the paradigm of personalised therapeutic intervention. Additional approaches for targeting the hypoxic tumour microenvironment are being investigated in pre-clinical and clinical studies that have potential for producing synthetic lethality in combination with anti-angiogenic therapy as a future therapeutic strategy.

Fatty acid-binding protein 4, a point of convergence for angiogenic and metabolic signaling pathways in endothelial cells

Fatty acid-binding protein 4 (FABP4) is an adipogenic protein and is implicated in atherosclerosis, insulin resistance, and cancer. In endothelial cells, FABP4 is induced by VEGFA, and inhibition of FABP4 blocks most of the VEGFA effects. We investigated the DLL4-NOTCH-dependent regulation of FABP4 in human umbilical vein endothelial cells by gene/protein expression and interaction analyses following inhibitor treatment and RNA interference. We found that FABP4 is directly induced by NOTCH. Stimulation of NOTCH signaling with human recombinant DLL4 led to FABP4 induction, independently of VEGFA. FABP4 induction by VEGFA was reduced by blockade of DLL4 binding to NOTCH or inhibition of NOTCH signal transduction. Chromatin immunoprecipitation of the NOTCH intracellular domain showed increased binding to two specific regions in the FABP4 promoter. The induction of FABP4 gene expression was dependent on the transcription factor FOXO1, which was essential for basal expression of FABP4, and FABP4 up-regulation following stimulation of the VEGFA and/or the NOTCH pathway. Thus, we show that the DLL4-NOTCH pathway mediates endothelial FABP4 expression. This indicates that induction of the angiogenesis-restricting DLL4-NOTCH can have pro-angiogenic effects via this pathway. It also provides a link between DLL4-NOTCH and FOXO1-mediated regulation of endothelial gene transcription, and it shows that DLL4-NOTCH is a nodal point in the integration of pro-angiogenic and metabolic signaling in endothelial cells. This may be crucial for angiogenesis in the tumor environment.

Proline-hydroxylated hypoxia-inducible factor 1α (HIF-1α) upregulation in human tumours

The stabilisation of HIF-α is central to the transcriptional response of animals to hypoxia, regulating the expression of hundreds of genes including those involved in angiogenesis, metabolism and metastasis. HIF-α is degraded under normoxic conditions by proline hydroxylation, which allows for recognition and ubiquitination by the von-Hippel-Lindau (VHL) E3 ligase complex. The aim of our study was to investigate the posttranslational modification of HIF-1α in tumours, to assess whether there are additional mechanisms besides reduced hydroxylation leading to stability. To this end we optimised antibodies against the proline-hydroxylated forms of HIF-1α for use in formalin fixed paraffin embedded (FFPE) immunohistochemistry to assess effects in tumour cells in vivo. We found that HIF-1α proline-hydroxylated at both VHL binding sites (Pro402 and Pro564), was present in hypoxic regions of a wide range of tumours, tumour xenografts and in moderately hypoxic cells in vitro. Staining for hydroxylated HIF-1α can identify a subset of breast cancer patients with poorer prognosis and may be a better marker than total HIF-1α levels. The expression of unhydroxylated HIF-1α positively correlates with VHL in breast cancer suggesting that VHL may be rate-limiting for HIF degradation. Our conclusions are that the degradation of proline-hydroxylated HIF-1α may be rate-limited in tumours and therefore provides new insights into mechanisms of HIF upregulation. Persistence of proline-hydroxylated HIF-1α in perinecrotic areas suggests there is adequate oxygen to support prolyl hydroxylase domain (PHD) activity and proline-hydroxylated HIF-1α may be the predominant form associated with the poorer prognosis that higher levels of HIF-1α confer.

Abstract BS02-1: Hypoxia metabolism in breast cancer – How to overcome resistance to anti-angiogenic therapy

Background. Hypoxia is recognised to induce a multigene programme mainly via HIF1a and also HIF2a transcription factors. Bioinformatics analysis of multiple gene array data sets in breast cancer showed a core hypoxia response programme of approximately 90 genes associated with poor outcome independently of other factors. This core response was significantly over-expressed in triple receptor negative cancers. Additionally, microRNAs associated with hypoxia were shown to give additional worse prognosis associations (mir-210). mir-210 targeted the mitochondrial iron chaperone responsible for regulation of key enzymes in the Krebs cycle and showed an adaptive response to hypoxia involving switching off the mitochondrial metabolism.

Aims and methods. To assess in human breast cancer the hypoxia transcriptome we conducted gene microarray studies before and after 2 weeks of bevacizumab 15mg/kg single dose before neoadjuvant chemotherapy. This was correlated with imaging by DCE-MRI Ktrans analysis.

Results. The study showed that high Ktrans was an excellent predictor for the biological affect of VEGF inhibition and extensive gene induction occurred, including many components of the HIF pathway, but also glycogen metabolism and lipid metabolism.

We investigated these further in xenograft models to see which of the adaption pathways may be most important for survival under hypoxic conditions. We showed that induction of CA9, a key enzyme regulating extracellular pH, was critical for survival under anti-angiogenic therapy and blocking CA9 could synergise and also produce radiosensitivity. Reactivating mitochondria under hypoxic conditions induced by angiogenesis also showed additional anti-cancer benefits and is the basis now for a new phase I study in our department.

Additionally, surprisingly, induction of glycogen and lipid storage occurred and this was essential for survival on reoxygenation and for protection against free radical damage, which greatly increased when either pathway was inhibited.

We investigated, by bioinformatic approaches, the expression of 133 key enzymes in metabolism, showed that they were strongly associated with different subtypes of breast cancer, which may help in selection of patients for future intervention studies.

To additionally define the hypoxia transcription, we conducted RNA sequencing of MCF7 cells in normoxia and mild hypoxia. This revealed marked induction of many long non-coding RNAs, suppression of all transfer RNAs and induction of novel antisense RNAs.

Conclusions. Overall, therefore, although anti-angiogenic therapy alone is now withdrawn from clinical utility in breast cancer, the massive induction of hypoxic microenvironment and synergy with many other therapeutics, suggests that as new approach using induced essentiality should be reassessed in breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr BS02-1.

Anxiety and affiliation in children

Hypotheses about the relationship between anxiety and affiliation derived from the psychoanalytic, drive, and social comparison models were tested by exposing high anxious (HA) and low anxious (LA)Ss to stress and subsequently to conditions meant to fulfill either nurturance or information needs. Unstressed and non-need fulfilled control groups were included. (N=224 grade school children.) Stress significantly increased the strength of adult affiliating in HA Ss; nurturance reduced it. Peer affiliating was not influenced by stress or information, nor did the conditions affect the affiliation of LASs. Results supported the hypothesis that dependency motives mediate the anxiety-affiliation relationship.

Abstract 4053: Hypoxic trans-activation of sodium dependent bicarbonate co-transporters regulates pH in 3D spheroids and promotes growth

Background: Carbonic anhydrase IX (CAIX) is strongly induced by hypoxia. CAIX extracellularly hydrates CO2 to HCO3− and H+, and we previously showed CAIX regulates pH in 3D spheroids. CAIX expression correlates with poor prognosis in most tumour types. We recently showed CAIX regulates tumour growth, necrosis and that knockdown enhances Bevacizumab treatment, highlighting the role of pH regulation in the hypoxic tumour milieu. We hypothesised that transport of HCO3−, which had been produced by CAIX extracellularly could facilitate quenching of intracellular H+. We identified increased expression of SLC4A4 (which encodes a bicarbonate transporter), in response to Bevacizumab, a treatment which increases the hypoxic fraction of cells, in vivo.

Method: We investigated a panel of cells lines (4 colon cancers, 2 glioblastomas, 1 breast cancer and 1 head and neck cancer) for changes in RNA expression of bicarbonate transporters in response to hypoxia (0.1% O2, 72 hours), and the role of HIF1α and HIF2α in key identified changes. We used a specific Na+ dependent bicarbonate transport inhibitor (SO859) to examine the effect of inhibition on pH regulation and growth in spheroids. Further to this we used shRNA knockdown of SLC4A4 and SLC4A9 in cell lines with increased hypoxic expression to further investigate their role.

Results: Hypoxia increased the RNA expression of one or more bicarbonate transporter in 6/8 cancer cell lines. The largest increases in expression change were for SLC4A4 in Ls174T and SCC25 (79.4 fold, p&lt;0.01 n=3: 2.4 fold, p&lt;0.05, n=3) and SLC4A9 in U87 and Ls174T (10.5 fold, p&lt;0.01 n=3; 19 fold, p&lt;0.01 n=3). SLC4A4 expression was regulated by HIF1α in Ls174T and SCC25 (p&lt;0.05, n=3). HIF1α bound directly to the HRE in the promoter of SLC4A4 in SCC25. SLC4A9 expression increase was regulated by HIF2α (80%) and HIF1α (29%) in Ls174T. SO859 treatment acidified the intracellular pH of cells in U87 spheroids. The most significant differences in pH were seen at the spheroid core (p&lt;0.001, n=20) and periphery (p&lt;0.001, n=20). U87 spheroids have HIF1α stabilisation and CAIX expression throughout, as detected by immunohistochemistry. Longer SO859 treatment of 24 hours resulted in a reduced effect on pH, suggesting a compensation mechanism. SO859 treatment reduced the spheroid growth rate of 4/4 cell lines tested, including MDA-MB-468 a cell line that showed no hypoxic increase in bicarbonate transport expression. In U87 spheroids, CAIX knockdown further reduced the reduction in growth rate seen with SO859. SLC4A4 and SLC4A9 knockdown reduced growth rate in Ls174T spheroids and SLC4A9 knockdown reduced spheroid growth rate in U87.

Conclusion: This work highlights the value of developing small molecules or antibodies, which inhibit bicarbonate transport to clinically deregulate pH regulation in the hypoxic microenvironment of tumours.

Citation Format: Alan McIntyre, Alzbeta Hulikova, Ioanna Ledaki, Peter Seden, Helen Turley, Dylan Jones, Angela Russell, Pawel Swietach, Adrian L. Harris. Hypoxic trans-activation of sodium dependent bicarbonate co-transporters regulates pH in 3D spheroids and promotes growth. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4053. doi:10.1158/1538-7445.AM2013-4053