Collagen-I influences the post-translational regulation, binding partners and role of Annexin A2 in breast cancer progression.

Introduction: The extracellular matrix (ECM) has been heavily implicated in the development and progression of cancer. We have previously shown that Annexin A2 is integral in the migration and invasion of breast cancer cells and in the clinical progression of ER-negative breast cancer, processes which are highly influenced by the surrounding tumor microenvironment and ECM. Methods: We investigated how modulations of the ECM may affect the role of Annexin A2 in MDA-MB-231 breast cancer cells using western blotting, immunofluorescent confocal microscopy and immuno-precipitation mass spectrometry techniques. Results: We have shown that the presence of collagen-I, the main constituent of the ECM, increases the post-translational phosphorylation of Annexin A2 and subsequently causes the translocation of Annexin A2 to the extracellular surface. In the presence of collagen-I, we identified fibronectin as a novel interactor of Annexin A2, using mass spectrometry analysis. We then demonstrated that reducing Annexin A2 expression decreases the degradation of fibronectin by cancer cells and this effect on fibronectin turnover is increased according to collagen-I abundance. Discussion: Our results suggest that Annexin A2's role in promoting cancer progression is mediated by collagen-I and Annexin A2 maybe a therapeutic target in the bi-directional cross-talk between cancer cells and ECM remodeling that supports metastatic cancer progression.

Communication, collaboration and contagion: "Virtualisation" of anatomy during COVID-19.

COVID-19 has generated a global need for technologies that enable communication, collaboration, education and scientific discourse whilst maintaining physical distance. University closures due to COVID-19 and physical distancing measures disrupt academic activities that previously occurred face-to-face. Restrictions placed on universities due to COVID-19 have precluded most conventional forms of education, assessment, research and scientific discourse. Anatomists now require valid, robust and easy-to-use communication tools to facilitate remote teaching, learning and research. Recent advances in communication, video conferencing and digital technologies may facilitate continuity of teaching and research activities. Examples include highly-interactive video conferencing technology, collaborative tools, social media and networking platforms. In this narrative review, we examine the utility of these technologies in supporting effective communication and professional activities of anatomists during COVID-19 and after.

Mechanically stimulated osteocytes promote the proliferation and migration of breast cancer cells via a potential CXCL1/2 mechanism.

Bone represents the most common site for breast cancer metastasis. Bone is a highly dynamic organ that is constantly adapting to its biophysical environment, orchestrated largely by the resident osteocyte network. Osteocytes subjected to physiologically relevant biophysical conditions may therefore represent a source of key factors mediating breast cancer cell metastasis to bone. Therefore, we investigated the potential proliferative and migratory capacity of soluble factors released by mechanically stimulated osteocytes on breast cancer cell behaviour. Interestingly the secretome of mechanically stimulated osteocytes enhanced both the proliferation and migration of cancer cells when compared to the secretome of statically cultured osteocytes, demonstrating that mechanical stimuli is an important physiological stimulus that should be considered when identifying potential targets. Using a cytokine array, we further identified a group of mechanically activated cytokines in the osteocyte secretome, which potentially drive breast cancer metastasis. In particular, CXCL1 and CXCL2 cytokines are highly expressed, mechanically regulated, and are known to interact with one another. Lastly, we demonstrate that these specific factors enhance breast cancer cell migration independently and in a synergistic manner, identifying potential osteocyte derived factors mediating breast cancer metastasis to bone.

Proposed hypothesis and rationale for association between mastitis and breast cancer.

Breast cancer is amongst the most common forms of cancer, is predominantly a woman's illness, and is the most frequently reported invasive cancer in women worldwide (Bray et al., 2018). Varying risk factors have been identified, including genetics, family history, lifestyle, age and the use of hormone replacement therapy. Mastitis, also predominantly a woman's illness, is an inflammatory condition of the breast that, despite being an inflammation-related condition, is not currently considered a risk factor for breast cancer. This appears counterintuitive as epidemiological studies have identified chronic inflammation as a contributor to cancer risk, for example in gastric, oesophageal and colon cancers (Lin et al., 2016; Qadri et al., 2014; Principe et al., 2017). Previous reports have focused on women hospitalised for mastitis, and most commonly on puerperal mastitis, perhaps underestimating the relationship between breast cancer and non-lactational mastitis. Our hypothesis, based on systematic review, suggests that a longitudinal study of this disease, affecting women predominantly, is warranted.

Collagen and fibronectin promote an aggressive cancer phenotype in breast cancer cells but drive autonomous gene expression patterns.

Understanding how various pathologies of breast cancer respond to their environment may be imperative in the creation of novel therapeutic targets. Central to the organisation and behaviour of cells within the tumour microenvironment is the extracellular matrix (ECM), a meshwork of fibrous proteins and glycoproteins that directly influences cell behaviour and the bioavailability of signalling molecules. Our appreciation on how the composition of the ECM can influence cancer behaviour has evolved significantly and although we are highly cognisant of the dramatic impact the ECM can have on cancer cell behaviour, we continue to neglect this during diagnosis and treatment. In the following study, we aimed to identify how three breast cancer cell lines respond functionally and genetically to common components of the ECM. Using real time and end point assays we have identified similar patterns of behaviour among the three breast cancer cell lines in response to commonly found ECM components of the breast. Using a selected gene panel, we have been able to identify cell line specific changes in gene differentiation when breast cancer cells are in contact with these elements. Although the response of our cells to these elements differ at the genetic level, their functional responses are consistent. This work adds to the growing arguments that highlight a need for histologically assessing ECM composition of breast tumours. In particular monitoring of fibrous protein deposition at the site of malignancy could provide critical information during clinical assessment influencing disease prognosis and treatment decisions for breast cancer patients.

Expression of Annexin A2 Promotes Cancer Progression in Estrogen Receptor Negative Breast Cancers.

When breast cancer progresses to a metastatic stage, survival rates decline rapidly and it is considered incurable. Thus, deciphering the critical mechanisms of metastasis is of vital importance to develop new treatment options. We hypothesize that studying the proteins that are newly synthesized during the metastatic processes of migration and invasion will greatly enhance our understanding of breast cancer progression. We conducted a mass spectrometry screen following bioorthogonal noncanonical amino acid tagging to elucidate changes in the nascent proteome that occur during epidermal growth factor stimulation in migrating and invading cells. Annexin A2 was identified in this screen and subsequent examination of breast cancer cell lines revealed that Annexin A2 is specifically upregulated in estrogen receptor negative (ER-) cell lines. Furthermore, siRNA knockdown showed that Annexin A2 expression promotes the proliferation, wound healing and directional migration of breast cancer cells. In patients, Annexin A2 expression is increased in ER- breast cancer subtypes. Additionally, high Annexin A2 expression confers a higher probability of distant metastasis specifically for ER- patients. This work establishes a pivotal role of Annexin A2 in breast cancer progression and identifies Annexin A2 as a potential therapeutic target for the more aggressive and harder to treat ER- subtype.

The deubiquitinase USP7 uses a distinct ubiquitin-like domain to deubiquitinate NF-ĸB subunits.

The transcription factor NF-ĸB is a master regulator of the innate immune response and plays a central role in inflammatory diseases by mediating the expression of pro-inflammatory cytokines. Ubiquitination-triggered proteasomal degradation of DNA-bound NF-ĸB strongly limits the expression of its target genes. Conversely, USP7 (deubiquitinase ubiquitin-specific peptidase 7) opposes the activities of E3 ligases, stabilizes DNA-bound NF-ĸB, and thereby promotes NF-ĸB-mediated transcription. Using gene expression and synthetic peptide arrays on membrane support and overlay analyses, we found here that inhibiting USP7 increases NF-ĸB ubiquitination and degradation, prevents Toll-like receptor-induced pro-inflammatory cytokine expression, and represents an effective strategy for controlling inflammation. However, the broad regulatory roles of USP7 in cell death pathways, chromatin, and DNA damage responses limit the use of catalytic inhibitors of USP7 as anti-inflammatory agents. To this end, we identified an NF-ĸB-binding site in USP7, ubiquitin-like domain 2, that selectively mediates interactions of USP7 with NF-ĸB subunits but is dispensable for interactions with other proteins. Moreover, we found that the amino acids 757LDEL760 in USP7 critically contribute to the interaction with the p65 subunit of NF-ĸB. Our findings support the notion that USP7 activity could be potentially targeted in a substrate-selective manner through the development of noncatalytic inhibitors of this deubiquitinase to abrogate NF-ĸB activity.

The regulation of sequence specific NF-κB DNA binding and transcription by IKKß phosphorylation of NF-κB p50 at serine 80.

Phosphorylation of the NF-κB transcription factor is an important regulatory mechanism for the control of transcription. Here we identify serine 80 (S80) as a phosphorylation site on the p50 subunit of NF-κB, and IKKß as a p50 kinase. Transcriptomic analysis of cells expressing a p50 S80A mutant reveals a critical role for S80 in selectively regulating the TNFα inducible expression of a subset of NF-κB target genes including pro-inflammatory cytokines and chemokines. S80 phosphorylation regulates the binding of p50 to NF-κB binding (κB) sites in a sequence specific manner. Specifically, phosphorylation of S80 reduces the binding of p50 at κB sites with an adenine at the -1 position. Our analyses demonstrate that p50 S80 phosphorylation predominantly regulates transcription through the p50:p65 heterodimer, where S80 phosphorylation acts in trans to limit the NF-κB mediated transcription of pro-inflammatory genes. The regulation of a functional class of pro-inflammatory genes by the interaction of S80 phosphorylated p50 with a specific κB sequence describes a novel mechanism for the control of cytokine-induced transcriptional responses.

Direct mechanical characterization of prostate tissue-a systematic review.

BACKGROUND: Direct mechanical characterization of tissue is the application of engineering techniques to biological tissue to ascertain stiffness or elasticity, which can change in response to disease states. A number of papers have been published on the application of these techniques to prostate tissue with a range of results reported. There is a marked variability in the results depending on testing techniques and disease state of the prostate tissue. We aimed to clarify the utility of direct mechanical characterization of prostate tissue in identifying disease states. METHODS: A systematic review of the published literature regarding direct mechanical characterization of prostate tissue was undertaking according to PRISMA guidelines. RESULTS: A variety of testing methods have been used, including compression, indentation, and tensile testing, as well as some indirect testing techniques, such as shear-wave elastography. There is strong evidence of significant stiffness differences between cancerous and non-cancerous prostate tissue, as well as correlations with prostate cancer stage. There is a correlation with increasing prostate stiffness and increasing lower urinary tract symptoms in patients with benign prostate hyperplasia. There is a wide variation in the testing methods and protocols used in the literature making direct comparison between papers difficult. Most studies utilise ex-vivo or cadaveric tissue, while none incorporate in vivo testing. CONCLUSION: Direct mechanical assessment of prostate tissue permits a better understanding of the pathological and physiological changes that are occurring within the tissue. Further work is needed to include prospective and in vivo data to aid medical device design and investigate non-surgical methods of managing prostate disease.

The Human Mesenteric Lymph Node Microbiome Differentiates Between Crohn's Disease and Ulcerative Colitis.

BACKGROUND AND AIMS: Mesenteric lymph nodes are sites in which translocated bacteria incite and progress immunological responses. For this reason, understanding the microbiome of mesenteric lymph nodes in inflammatory bowel disease is important. The bacterial profile of Crohn's disease mesenteric lymph nodes has been analysed using culture-independent methods in only one previous study. This study aimed to investigate the mesenteric lymph node microbiota from both Crohn's disease and ulcerative colitis patients. METHODS: Mesenteric lymph nodes were collected from Crohn's disease and ulcerative colitis patients undergoing resection. Total DNA was extracted from mesenteric lymph nodes and assessed for the presence of bacterial DNA [16S]. All work was completed in a sterile environment using aseptic techniques. Samples positive for 16S DNA underwent next-generation sequencing, and the identity of bacterial phyla and species were determined. RESULTS: Crohn's disease mesenteric lymph nodes had a distinctly different microbial profile to that observed in ulcerative colitis. The relative abundance of Firmicutes was greater in nodes from ulcerative colitis patients, whereas Proteobacteria were more abundant in Crohn's disease. Although species diversity was reduced in the mesenteric lymph nodes of patients with Crohn's disease, these lymph nodes contained greater numbers of less dominant phyla, mainly Fusobacteria. CONCLUSION: This study confirms that there are distinct differences between the Crohn's disease and ulcerative colitis mesenteric lymph node microbiomes. Such microbial differences could aid in the diagnosis of Crohn's disease or ulcerative colitis, particularly in cases of indeterminate colitis at time of resection, or help explain their mechanisms of development and progression.

ATP synthase F1 subunits recruited to centromeres by CENP-A are required for male meiosis.

The histone H3 variant CENP-A epigenetically defines the centromere and is critical for chromosome segregation. Here we report an interaction between CENP-A and subunits of the mitochondrial ATP synthase complex in the germline of male Drosophila. Furthermore, we report that knockdown of CENP-A, as well as subunits ATPsyn-α, -ßlike (a testis-specific paralogue of ATPsyn-ß) and -γ disrupts sister centromere cohesion in meiotic prophase I. We find that this disruption is likely independent of reduced ATP levels. We identify that ATPsyn-α and -ßlike localise to meiotic centromeres and that this localisation is dependent on the presence of CENP-A. We show that ATPsyn-α directly interacts with the N-terminus of CENP-A in vitro and that truncation of its N terminus perturbs sister centromere cohesion in prophase I. We propose that the CENP-A N-terminus recruits ATPsyn-α and -ßlike to centromeres to promote sister centromere cohesion in a nuclear function that is independent of oxidative phosphorylation.

Regulation of muscle protein synthesis in an in vitro cell model using ex vivo human serum.

NEW FINDINGS: What is the central question of this study? Can medium conditioned by ex vivo human serum regulate muscle protein synthesis in skeletal muscle cells in vitro? What is the main finding and its importance? This study demonstrates that medium conditioned by ex vivo human serum can regulate muscle protein synthesis in skeletal muscle cells in vitro via the mammalian Target of Rapomycin (mTOR) pathway, and this can be regulated differentially by fed and fasted ex vivo human serum. ABSTRACT: Human serum embodies the integrated systemic response to any condition or perturbation, which may regulate muscle protein synthesis (MPS). Conditioning of medium with human serum represents a physiologically relevant method of regulating MPS in vitro. The primary purpose of the study was the development of a model using ex vivo human serum to condition medium and regulate MPS in in vitro skeletal muscle cells. Four young healthy men reported to the laboratory after an overnight fast and were fed with 0.33 g (kg body mass)-1 whey protein. Blood samples were taken before (Fasted) and 60 min postprandial (Fed). Fully differentiated C2C12 skeletal muscle cells were nutrient and serum deprived for 1 h and subsequently treated with medium conditioned with Fasted or Fed ex vivo human serum (20%) for 4 h. The MPS was measured using the surface sensing of translation technique and activation of mTOR, P70S6K and 4EBP1 by Western blot. Fasted and fed ex vivo human serum increased MPS (P < 0.05). Although a strong effect (ƞ2  = 0.36) for increased MPS in Fed relative to Fasted was observed, this was not statistically significant (P > 0.05). Activation of mTOR, P70S6K and 4EBP1 was significantly increased after treatment with Fed compared with Fasted ex vivo human serum (P < 0.05). Here, we developed and optimized the conditions for culture of C2C12 skeletal muscle cells, measurement of MPS and signalling in medium conditioned by ex vivo human serum. Furthermore, the functionality of the model was demonstrated by comparison of the response to medium conditioned by Fasted and Fed ex vivo human serum.

Inclusion of the Mesentery in Ileocolic Resection for Crohn's Disease is Associated With Reduced Surgical Recurrence.

BACKGROUND AND AIMS: Inclusion of the mesentery during resection for colorectal cancer is associated with improved outcomes but has yet to be evaluated in Crohn's disease. This study aimed to determine the rate of surgical recurrence after inclusion of mesentery during ileocolic resection for Crohn's disease. METHODS: Surgical recurrence rates were compared between two cohorts. Cohort A [n = 30] underwent conventional ileocolic resection where the mesentery was divided flush with the intestine. Cohort B [n = 34] underwent resection which included excision of the mesentery. The relationship between mesenteric disease severity and surgical recurrence was determined in a separate cohort [n = 94]. A mesenteric disease activity index was developed to quantify disease severity. This was correlated with the Crohn's disease activity index and the fibrocyte percentage in circulating white cells. RESULTS: Cumulative reoperation rates were 40% and 2.9% in cohorts A and B [P = 0.003], respectively. Surgical technique was an independent determinant of outcome [P = 0.007]. Length of resected intestine was shorter in cohort B, whilst lymph node yield was higher [12.25 ± 13 versus 2.4 ± 2.9, P = 0.002]. Advanced mesenteric disease predicted increased surgical recurrence [Hazard Ratio 4.7, 95% Confidence Interval: 1.71-13.01, P = 0.003]. The mesenteric disease activity index correlated with the mucosal disease activity index [r = 0.76, p < 0.0001] and the Crohn's disease activity index [r = 0.70, p < 0.0001]. The mesenteric disease activity index was significantly worse in smokers and correlated with increases in circulating fibrocytes. CONCLUSIONS: Inclusion of mesentery in ileocolic resection for Crohn's disease is associated with reduced recurrence requiring reoperation.

Expression of protein kinase C gamma promotes cell migration in colon cancer.

Despite extensive efforts, Protein Kinase Cs (PKCs) have proven to be an intractable target in cancer therapies. Traditionally it was accepted that PKCs act as tumour promoters, however new research suggests that PKCs may play an important role in the suppression of cancer. A challenge in targeting PKCs is the limited data available in patient samples. One of the PKC isozymes, PKC gamma, is thought to be present only in the brain and has been largely neglected in the context of cancer. Analysis of gene expression levels of PKC gamma in patient matched normal and colon cancer tissue samples revealed an up-regulation of the gene in the cancer tissue of 54% of the patients examined. Mechanistically we demonstrate that a reduction in the levels of PKC gamma in the colon cancer cells inhibits cell migration and foci formation. Further to this, we observe an increase in cell adhesion and proliferation following the reduction of PKC gamma levels in the cell. Thus, PKC gamma plays a key role in colon cancer; making it an important isozyme that needs to be reconsidered in the context of cancer therapies.

Enhanced cell viability in hyaluronic acid coated poly(lactic-co-glycolic acid) porous scaffolds within microfluidic channels.

The concept of the present work is to produce porous optimised scaffolds of poly(lactic-co-glycolic acid) (PLGA) coated with hyaluronic acid (HA), to provide a suitable microenvironment for cellular proliferation. Freeze dried scaffolds were produced from PLGA with varying lactic acid and glycolic acid ratios along the polymer backbone, as follows: 50:50 ester terminated, 50:50 carboxylate end-group and 85:15 ester terminated. Subsequently, these scaffolds were immersed in crosslinked HA in order for the coating to enhance biological performance. Scaffolds were fully characterized with respect to surface morphology, physical and chemical properties. The biocompatibility of the scaffolds was firstly evaluated using standard L929 fibroblast cells in static culture and subsequently MCF-7 breast cancer cells were seeded on scaffolds which were incorporated within a microfluidic device. The results show that cells were attracted to and adhered to the scaffolds, with a higher affinity for HA coated scaffolds. In our system, cell viability was maintained up to 48h.

RACK1 stabilises the activity of PP2A to regulate the transformed phenotype in mammary epithelial cells.

Conflicting reports implicate the scaffolding protein RACK1 in the progression of breast cancer. RACK1 has been identified as a key regulator downstream of growth factor and adhesion signalling and as a direct binding partner of PP2A. Our objective was to further characterise the interaction between PP2A and RACK1 and to advance our understanding of this complex in breast cancer cells. We examined how the PP2A holoenzyme is assembled on the RACK1 scaffold in MCF-7 cells. We used immobilized peptide arrays representing the entire PP2A-catalytic subunit to identify candidate amino acids on the C subunit of PP2A that might be involved in binding of RACK1. We identified the RACK1 interaction sites on PP2A. Stable cell lines expressing PP2A with FR69/70AA, R214A and Y218F substitutions were generated and it was confirmed that the RACK1/PP2A interaction is essential to stabilise PP2A activity. We used Real-Time Cell Analysis and a series of assays to demonstrate that disruption of the RACK1/PP2A complex also reduces the adhesion, proliferation, migration and invasion of breast cancer cells and plays a role in maintenance of the cancer phenotype. This work has significantly advanced our understanding of the RACK1/PP2A complex and suggests a pro-carcinogenic role for the RACK1/PP2A interaction. This work suggests that approaches to target the RACK1/PP2A complex are a viable option to regulate PP2A activity and identifies a novel potential therapeutic target in the treatment of breast cancer.

Extracellular matrix gene expression profiling using microfluidics for colorectal carcinoma stratification.

In cancer, biomarkers have many potential applications including generation of a differential diagnosis, prediction of response to treatment, and monitoring disease progression. Many molecular biomarkers have been put forward for different diseases but most of them do not possess the required specificity and sensitivity. A biomarker with a high sensitivity has a low specificity and vice versa. The inaccuracy of the biomarkers currently in use has led to a compelling need to identify more accurate markers with diagnostic and prognostic significance. The aim of the present study was to use a novel, droplet-based, microfluidic platform to evaluate the prognostic value of a panel of thirty-four genes that regulate the composition of extracellular matrices in colorectal carcinoma. Our method is a novel approach as it uses using continuous-flowing Polymerase Chain Reaction for the sensitive detection and accurate quantitation of gene expression. We identified a panel of relevant extracellular matrix genes whose expression levels were measured by real-time quantitative polymerase chain reaction using Taqman® reagents in twenty-four pairs of matched colorectal cancer tumour and associated normal tissue. Differential expression patterns occurred between the normal and malignant tissue and correlated with histopathological parameters and overall surgical staging. The findings demonstrate that a droplet-based microfluidic quantitative PCR system enables biomarker classification. It was further possible to sub-classify colorectal cancer based on extracellular matrix protein expressing groups which in turn correlated with prognosis.

Big Data-Led Cancer Research, Application, and Insights.

Insights distilled from integrating multiple big-data or "omic" datasets have revealed functional hierarchies of molecular networks driving tumorigenesis and modifiers of treatment response. Identifying these novel key regulatory and dysregulated elements is now informing personalized medicine. Crucially, although there are many advantages to this approach, there are several key considerations to address. Here, we examine how this big data-led approach is impacting many diverse areas of cancer research, through review of the key presentations given at the Irish Association for Cancer Research Meeting and importantly how the results may be applied to positively affect patient outcomes. Cancer Res; 76(21); 6167-70. ©2016 AACR.

Activation of the cAMP Pathway Induces RACK1-Dependent Binding of ß-Actin to BDNF Promoter.

RACK1 is a scaffolding protein that contributes to the specificity and propagation of several signaling cascades including the cAMP pathway. As such, RACK1 participates in numerous cellular functions ranging from cell migration and morphology to gene transcription. To obtain further insights on the mechanisms whereby RACK1 regulates cAMP-dependent processes, we set out to identify new binding partners of RACK1 during activation of the cAMP signaling using a proteomics strategy. We identified ß-actin as a direct RACK1 binding partner and found that the association between ß-actin and RACK1 is increased in response to the activation of the cAMP pathway. Furthermore, we show that cAMP-dependent increase in BDNF expression requires filamentous actin. We further report that ß-actin associates with the BDNF promoter IV upon the activation of the cAMP pathway and present data to suggest that the association of ß-actin with BDNF promoter IV is RACK1-dependent. Taken together, our data suggest that ß-actin is a new RACK1 binding partner and that the RACK1 and ß-actin association participate in the cAMP-dependent regulation of BDNF transcription.

Studying protein-protein interactions: progress, pitfalls and solutions.

Signalling proteins are intrinsic to all biological processes and interact with each other in tightly regulated and orchestrated signalling complexes and pathways. Characterization of protein binding can help to elucidate protein function within signalling pathways. This information is vital for researchers to gain a more comprehensive knowledge of cellular networks which can then be used to develop new therapeutic strategies for disease. However, studying protein-protein interactions (PPIs) can be challenging as the interactions can be extremely transient downstream of specific environmental cues. There are many powerful techniques currently available to identify and confirm PPIs. Choosing the most appropriate range of techniques merits serious consideration. The aim of this review is to provide a starting point for researchers embarking on a PPI study. We provide an overview and point of reference for some of the many methods available to identify interactions from in silico analysis and large scale screening tools through to the methods used to validate potential PPIs. We discuss the advantages and disadvantages of each method and we also provide a workflow chart to highlight the main experimental questions to consider when planning cell lysis to maximize experimental success.