Immunotherapeutic Interleukin-6 or Interleukin-6 Receptor Blockade in Cancer: Challenges and Opportunities

Interleukin 6 (IL-6), a well-known pro-inflammatory cytokine with pleiotropic activity is a central player in chronic inflammatory diseases including cancers. Therefore, blockade of the IL-6 signalling pathway has become a target for the therapy of diverse cancers such as multicentric Castleman's disease (CD), multiple myeloma and solid tumours including renal, prostate, lung, colorectal and ovarian cancers. Monoclonal antibodies against IL-6 (Siltuximab) and the IL-6 receptor (IL-6R) (Tocilizumab) have emerged as potential immunotherapies, alone or in combination with conventional chemotherapy. Human trials have demonstrated the ability to block IL-6 activity and in multicentric CD lead to durable clinical response and longer disease stabilisation. However, the efficacy of these treatments is still debatable for other cancers. New generation therapeutics in development such as Clazakizumab, Sarilumab, and soluble gp130-Fc have the additional features of improved binding affinity, better specificity with reduced adverse effects. A deeper understanding of the immunological basis of these agents, as well as of the challenges that are faced by immunotherapy-based products in clinical trials, will help select the most promising anti-IL-6/IL-6R therapies for large scale use. Concurrently, current research efforts to personalize treatments may help in the treatment of patients that would greatly benefit from IL-6 blocking therapies.

New Trends in Anti-Cancer Therapy: Combining Conventional Chemotherapeutics with Novel Immunomodulators

Cancer is one of the leading causes of death worldwide, and current research has focused on the discovery of novel approaches to effectively treat this disease. Recently, a considerable number of clinical trials have demonstrated the success of immunomodulatory therapies for the treatment of cancer. Monoclonal antibodies can target components of the immune system to either i) agonise co-stimulatory molecules, such as CD137, OX40 and CD40; or ii) inhibit immune checkpoints, such as cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), programmed cell death-1 (PD-1) and its corresponding ligand PD-L1. Although tumour regression is the outcome for some patients following immunotherapy, many patients still do not respond. Furthermore, chemotherapy has been the standard of care for most cancers, but the immunomodulatory capacity of these drugs has only recently been uncovered. The ability of chemotherapy to modulate the immune system through a variety of mechanisms, including immunogenic cell death (ICD), increased antigen presentation and depletion of regulatory immune cells, highlights the potential for synergism between conventional chemotherapy and novel immunotherapy. In addition, recent pre-clinical trials indicate dipeptidyl peptidase (DPP) enzyme inhibition, an enzyme that can regulate immune cell trafficking to the tumour microenvironment, as a novel cancer therapy. The present review focuses on the current immunological approaches for the treatment of cancer, and summarizes clinical trials in the field of immunotherapy as a single treatment and in combination with chemotherapy.

Sperm Protein 17 Expression by Murine Epithelial Ovarian Cancer Cells and Its Impact on Tumor Progression

The cancer testis antigen sperm protein 17 (Sp17) is a promising antigenic target in epithelial ovarian cancer (EOC) vaccine development. However, its role in ovarian cancer is unclear. We isolated and expanded Sp17⁺ and Sp17⁻ clones from the murine EOC cell line ID8, and compared their in-vitro cell growth characteristics and in-vivo tumorigenicity. We also examined the potential co-expression of molecules that may influence cancer cell survival and interaction with immune cells. These include stimulatory and immunosuppressive molecules, such as major histocompatibility class I molecules (MHC I), MHC II, cytotoxic T lymphocyte associated antigen-4 (CTLA-4), CD73, CD39, tumor necrosis factor receptor II (TNFRII), signal transducer and activator of transcription 3 (STAT3) and programmed death-ligand 1 (PD-L1). Whilst the presence of Sp17 was not correlated with the ID8 cell proliferation/growth capacity in vitro, it was critical to enable progressive tumor formation in vivo. Flow cytometry revealed that Sp17⁺ ID8 cells displayed higher expression of both STAT3 and PD-L1, whilst MHC II expression was lower. Moreover, Sp17^high (PD-L1⁺MHCII⁻) cell populations showed significantly enhanced resistance to Paclitaxel-induced cell death in vitro compared to Sp17^low (PD-L1⁻MHCII⁺) cells, which was associated in turn with increased STAT3 expression. Together, the data support Sp17 as a factor associated with in-vivo tumor progression and chemo-resistance, validating it as a suitable target for vaccine development.

The Driver Behaviour Questionnaire for older drivers: Do errors, violations and lapses change over time?

The aim of the current study was to examine how self-reported aberrant driving behaviours change across a three time-points in a group of older drivers. Two hundred and twenty-seven older drivers (males = 69.6%) from the Candrive/Ozcandrive longitudinal study completed the Driving Behaviour Questionnaire (DBQ) each yearacross three time-points (i.e., Year 1, Year 2, Year 3). At the third time-point, older drivers ranged in age from 77 to 96 years (M = 81.74 years; SD = 3.44 years). A longitudinal confirmatory factor analysis showed that a modified 21-item, 3-factor (errors, lapses and violations) DBQ was invariant across the time period, suggesting that the structure of the questionnaire was stable across each time-point. Further, multiple domain latent growth analysis on the resultant factors for errors, lapses and violations showed that the frequency of errors remained similar across the three-year period, while violations and lapses showed very marginal decreases in frequency. These changes were independent of the absolute number of these behaviours; Drivers with higher violations or lapses in Year one, showed similar decreases in frequency as those who self-reported lower frequencies of the behaviours. These results suggest that the DBQ is a reliable tool to measure older drivers' self-reported aberrant driving behaviours, and that these behaviours do not show much change across time. Future research should validate the self-reported responses from the DBQ with more objective measures such as those collected through naturalistic driving study (NDS) methodology or on-road driving tasks.

Measuring PC activity in endocervical swab may provide a simple and non-invasive method to detect endometrial cancer in post-menopausal women

Endometrial cancer is one of the most common gynecological malignancies in post-menopausal women. If detected at early stages, endometrial cancer can be effectively treated by abdominal hysterectomy. However, to date, there is no biochemical test available for early and easy detection of endometrial cancer. Our previous study has established that the total proprotein convertase (PC) activity is significantly increased in the uterine lavage of post-menopausal women with endometrial cancer. Uterine lavage can be obtained relatively non-invasively compared to uterine tissues, however, blood contamination and other factors limit the wide clinical use of uterine lavage. The aim of this study was to determine whether endocervical swab is a viable alternative to uterine lavage for the detection of endometrial cancer. We determined the correlation in PC activity between paired endocervical swabs and uterine lavages from individual post-menopausal women (control as well as endometrial cancer patients), and also compared the total PC activity in endocervical swabs between control and endometrial cancer patients. Our data demonstrated that the total PC activity in swab and lavage was highly correlative in post-menopausal women, and that the PC activity in endocervical swab was significantly increased in endometrial cancer patients compared to controls. These results strongly suggest that determining PC activity in endocervical swabs may provide a simple, non-invasive and novel method to detect endometrial cancer in post-menopausal women.

Autoantibodies against HSF1 and CCDC155 as Biomarkers of Early-Stage, High-Grade Serous Ovarian Cancer

Background: Tumor-directed circulating autoantibodies (AAb) are a well-established feature of many solid tumor types, and are often observed prior to clinical disease manifestation. As such, they may provide a good indicator of early disease development. We have conducted a pilot study to identify novel AAbs as markers of early-stage HGSOCs.Methods: A rare cohort of patients with early (FIGO stage Ia-c) HGSOCs for IgG, IgA, and IgM-mediated AAb reactivity using high-content protein arrays (containing 9,184 individual proteins). AAb reactivity against selected antigens was validated by ELISA in a second, independent cohort of individual patients.Results: A total of 184 antigens were differentially detected in early-stage HGSOC patients compared with all other patient groups assessed. Among the six most highly detected "early-stage" antigens, anti-IgA AAbs against HSF1 and anti-IgG AAbs CCDC155 (KASH5; nesprin 5) were significantly elevated in patients with early-stage malignancy. Receiver operating characteristic (ROC) analysis suggested that AAbs against HSF1 provided better detection of early-stage malignancy than CA125 alone. Combined measurement of anti-HSF1, anti-CCDC155, and CA125 also improved efficacy at higher sensitivity.Conclusions: The combined measurement of anti-HSF1, anti-CCDC155, and CA125 may be useful for early-stage HGSOC detection.Impact: This is the first study to specifically identify AAbs associated with early-stage HGSOC. The presence and high frequency of specific AAbs in early-stage cancer patients warrants a larger scale examination to define their value for early disease detection at primary diagnosis and/or recurrence. Cancer Epidemiol Biomarkers Prev; 27(2); 183-92. ©2017 AACR.

Interleukin 6 Present in Inflammatory Ascites from Advanced Epithelial Ovarian Cancer Patients Promotes Tumor Necrosis Factor Receptor 2-Expressing Regulatory T Cells

Background

Epithelial ovarian cancer (EOC) remains a highly lethal gynecological malignancy. Ascites, an accumulation of peritoneal fluid present in one-third of patients at presentation, is linked to poor prognosis. High levels of regulatory T cells (Tregs) in ascites are correlated with tumor progression and reduced survival. Malignant ascites harbors high levels of Tregs expressing the tumor necrosis factor receptor 2 (TNFR2), as well as pro-inflammatory factors such as interleukin 6 (IL-6) and tumor necrosis factor (TNF). IL-6 is also associated with poor prognosis. Herein, we study the effect of IL-6 and TNF present in ascites on the modulation of TNFR2 expression on T cells, and specifically Tregs.

Methods

Ascites and respective peripheral blood sera were collected from 18 patients with advanced EOC and soluble biomarkers, including IL-6, sTNFR2, IL-10, TGF-β, and TNF, were quantified using multiplexed bead-based immunoassay. Peripheral blood mononuclear cells (PBMC) from healthy donors were incubated with cell-free ascites for 48 h (or media as a negative control). In some experiments, IL-6 or TNF within the ascites were neutralized by using monoclonal antibodies. The phenotype of TNFR2⁺ Tregs and TNFR2⁻ Tregs were characterized post incubation in ascites. In some experiments, cell sorted Tregs were utilized instead of PBMC.

Results

High levels of immunosuppressive (sTNFR2, IL-10, and TGF-β) and pro-inflammatory cytokines (IL-6 and TNF) were present in malignant ascites. TNFR2 expression on all T cell subsets was higher in post culture in ascites and highest on CD4⁺CD25^hiFoxP3⁺ Tregs, resulting in an increased TNFR2⁺ Treg/effector T cell ratio. Furthermore, TNFR2⁺ Tregs conditioned in ascites expressed higher levels of the functional immunosuppressive molecules programmed cell death ligand-1, CTLA-4, and GARP. Functionally, TNFR2⁺ Treg frequency was inversely correlated with interferon-gamma (IFN-γ) production by effector T cells, and was uniquely able to suppress TNFR2⁺ T effectors. Blockade of IL-6, but not TNF, within ascites decreased TNFR2⁺ Treg frequency. Results indicating malignant ascites promotes TNFR2 expression, and increased suppressive Treg activity using PBMC were confirmed using purified Treg subsets.

Conclusion

IL-6 present in malignant ovarian cancer ascites promotes increased TNFR2 expression and frequency of highly suppressive Tregs.

Gender roles, sex and the expression of driving anger

The present study investigated the validity of the 25-item Driving Anger Expression Inventory (DAX) as well as the role of sex and gender-roles in relation to the expression of driving anger in a sample of 378 French drivers (males=38%, M=32.9years old). Confirmatory Factor Analysis supported the four-factor structure of the 25-item DAX (Adaptive/Constructive Expression; Use of the Vehicle to Express Anger; Verbal Aggressive Expression and Personal Physical Aggressive Expression) and two of the three aggressive factors were found to have significant positive relationships with driving anger, while adaptive/constructive expression was negatively related to driving anger. Use of the vehicle to express anger was not significantly related to crash involvement, but was significantly related to all other crash-related conditions (traffic tickets, loss of concentration, loss of control of the vehicle, near crash). The presence of feminine traits, but not sex, was predictive of adaptive/constructive behaviours, while masculine traits predicted more frequent verbal aggressive expression, use of the vehicle to express anger, personal physical aggressive expression and total aggressive expression. This finding may account for the inconsistent relationship found between driving anger and sex in previous research. This research also found that the 25-item DAX is a valid tool to measure the expression of driving anger and that the endorsement of masculine traits are related to more aggressive forms of driving anger expression.

Self-reported speed compliance and attitudes towards speeding in a representative sample of drivers in Australia

BACKGROUND

Vehicle speed is a major contributor to road trauma, both in terms of increased crash risk and injury severity. In Australia, approximately one third of fatal crashes occur in speed zones of 100km/h. This proportion has remained the same, despite the reduction in the number of road fatalities over the past decade. To drive further reductions in speed-related crashes, an improved understanding of the underlying determinants of speed choice is required.

METHOD

A community attitude survey designed to understand speed behaviour and attitudes towards speeding was distributed to a large (N=5179) representative sample of drivers in Australia. Participants provided information regarding their normal speed choices across four different speed zones (40, 50, 60 and 100km/h), beliefs about the risks and enforcement of speeding behaviour as well as technology to reduce speeding.

RESULTS

Almost half of the sample (47%) reported exceeding the speed limit in 100km/h zones, although only a small number of these drivers (<0.5%) did so by 11km/h or more. Age and sex were related to speed limit non-compliance. Males were more likely to be classified as mid-level speeders, defined as being up to 10km/h over the limit, and excessive speeders (11+km/h over the limit). Younger drivers were also more likely to be non-compliant. When compared to compliant drivers, non-compliers perceived less risk of a serious crash, reported greater likelihood of exceeding the speed limit when they believed they would not be detected, and reported a higher level of social acceptability of speeding. Only one-third of the sample reported prior knowledge of intelligent speed assist (ISA) technology, however, once explained, the majority agreed it would be personally useful (64%). Speed non-compliers were somewhat less likely to support the usefulness of ISA than speed limit compliant drivers.

CONCLUSION

These findings can be used to target appropriate interventions and road safety messages, aimed at reducing speeding behaviour. Measures designed to address perceived social acceptability of speed behaviour, the increased crash risk associated with speeding, and the threat of detection are recommended.

The relationship between Motorcycle Rider Behaviour Questionnaire scores and crashes for riders in Australia

Motorcycle riders are over-represented in road fatalities in Australia. While riders represent 18% of the road users killed each year, motorcycle registrations constitute only 4.5% of the registered vehicle fleet. The Motorcycle Rider Behaviour Questionnaire (MRBQ) was developed with a view toward understanding behaviours likely to be associated with crash risk. These include behaviours that are either intentional (such as violations of road and speed regulations and stunts) or unintentional (such as errors relating to traffic or control of the motorcycle), as well as protective behaviours related to use of safety equipment. The dual aims of the current study were, first, to determine the appropriate structure of a modified version of the MRBQ for use in a representative sample of riders in Australia and, second, to understand which MRBQ factors are associated with crash involvement. A stratified sampling procedure was undertaken to ensure the socio-economic status of local government area, age and gender of the sample was representative of the broader population of riders in New South Wales, Australia. The sample consisted of 470 riders (males=89%). Exploratory factor analysis revealed a 29-item, five factor structure was suitable on the Australian data encompassing traffic errors, speed violations, protective gear, control errors and stunts. Overall, riders reported relatively safe behaviours, with frequent use of protective gear and infrequent aberrant behaviours. However, even though infrequent, violations of speed and errors related to control of the motorcycle increased the odds of near-crash involvement, whilst stunt behaviours were associated with increased odds of crash involvement. Interventions and countermeasures need to target these specific behaviours.

Gender Roles and the Expression of Driving Anger Among Ukrainian Drivers

The current study investigated the validity of the revised (25-item) version of the driving anger expression inventory (DAX) on a novel sample of 385 drivers from Ukraine. The roles of sex and gender in relation to self-reported aggressive tendencies were also examined. Confirmatory factor analysis supported the four-factor structure of the DAX (adaptive/constructive expression; use of the vehicle to express anger; verbal aggressive expression; and personal physical aggressive expression), and the three aggressive factors were found to have positive relationships with trait anger and driving anger, while adaptive/constructive expression was negatively related to trait and driving anger. Drivers who reported recent near-misses or loss of concentration scored higher on verbal aggressive expression. Those who had recently received a traffic ticket also reported higher levels of all three types of aggressive anger expression. Further, the presence of feminine traits, but not sex, predicted more adaptive/constructive behaviors and lower scores for verbal aggressive expression, personal physical aggressive expression, and total aggressive expression. However, masculine traits did not predict any of these factors. This research concludes that the revised DAX is a valid tool to measure the expression of driving anger and that the endorsement of feminine traits is related to less aggressive expression of driving anger.

Alcohol consumption patterns and attitudes toward drink-drive behaviours and road safety enforcement strategies

BACKGROUND

Alcohol contributes to approximately 30% of all serious crashes. While the majority of drivers acknowledge the risks associated with drink-driving, a significant proportion of the population continue to engage in this behaviour. Attitudes towards drink-driving as well as personal alcohol consumption patterns are likely to underpin a driver's decision to drink-drive. These associations were explored in the current study.

METHODS

A large (N=2994) cross-sectional online survey of a representative sample of drivers in Australia was conducted. Participants provided information about their own alcohol consumption patterns, drink-driving behaviour as well as attitudes towards drink-driving (own and others) and enforcement strategies.

RESULTS

Alcohol consumption patterns differed according to age, gender and work status. Drivers who reported drink-driving behaviour and had high risk alcohol consumption patterns were less likely to agree that drink-driving leads to increased crash risk and more likely to agree they drink and drive when they believed they could get away with it. In contrast, drivers who did not report drink-driving and had low risk consumption patterns were more likely to report that the enforcement strategies are too lenient. Binary logistic regression showed that high risk alcohol consumption patterns and agreement from drivers that they drink and drive when they believe they can get away with it had the strongest associations with drink-driving. These findings highlight the relationships between one's drinking patterns, drink-drive behaviour and attitudes towards drink-driving and drink-driving enforcement CONCLUSIONS AND IMPLICATIONS: The patterns of associations that emerged suggest that drink-driving is the expression of a broader health issue for the most "at-risk" cohort of drinkers. The decision to drink and drive may result from a need borne from an alcohol dependent lifestyle exacerbated by a social acceptability of the behaviour and positive attitudes towards one's ability to drink-drive with few adverse consequences. Therefore, the broader alcohol consumption patterns of drink-drivers needs to be considered when targeting drink-drive reductions.

Total PC Activity Is Increased in Uterine Lavage of Post-Menopausal Endometrial but Not Ovarian Cancer Patients

Endometrial and ovarian cancers are two most common cancers affecting women in their post-menopausal years. To date, there are no simple biochemical tests to detect these cancers at early stages. Our previous study has demonstrated that the activity of total proprotein convertases (PCs) is significantly increased in uterine lavage at all stages of endometrial cancer, suggesting uterine lavage which can be obtained relatively non-invasively may provide a simple tool for the detection of endometrial cancer. However, uterine lavage may also contain ovarian-derived factors, and PCs are also reported to be up-regulated in ovarian cancer. In this study we determined whether increases in uterine lavage PC activity are specific to endometrial cancer or are also associated with ovarian cancer. PC activity was detected in all uterine lavages examined but no difference was found between women with and without ovarian cancer. On the other hand, the PC activity was significantly higher in post-menopausal endometrial cancer patients, consistent with our previous report. These results suggest that measuring total PC activity in uterine lavage is a useful tool to detect endometrial cancer specifically.

Driving anger in Ukraine: Appraisals, not trait driving anger, predict anger intensity while driving

Trait driving anger is often, but not always, found to predict both the intensity of anger while driving and subsequent crash-related behaviours. However, a number of studies have not found support for a direct relationship between one's tendency to become angry and anger reported while driving, suggesting that other factors may mediate this relationship. The present self-report study investigated whether, in anger provoking driving situations, the appraisals made by drivers influence the relationship between trait and state anger. A sample of 339 drivers from Ukraine completed the 33-item version of the Driver Anger Scale (DAS; Deffenbacher et al., 1994) and eight questions about their most recent experience of driving anger. A structural equation model found that the intensity of anger experienced was predicted by the negative evaluations of the situation, which was in turn predicted by trait driving anger. However, trait driving anger itself did not predict anger intensity; supporting the hypothesis that evaluations of the driving situation mediate the relationship between trait and state anger. Further, the unique structure of the DAS required to fit the data from the Ukrainian sample, may indicate that the anger inducing situations in Ukraine are different to those of a more developed country. Future research is needed to investigate driving anger in Ukraine in a broader sample and also to confirm the role of the appraisal process in the development of driving anger in both developed and undeveloped countries.

Abstract B08: Genomics analyses of less common epithelial ovarian cancer subtypes

While the genomics of high-grade serous carcinoma are well-studied in large international consortia, the less common subtypes have been neglected. We have sought to rectify this gap by analyzing international collections of low-grade serous and mucinous ovarian carcinomas and their putative benign and borderline precursors.

Exome sequencing and copy number analysis of low-grade serous carcinomas (n=9) and serous borderline tumours (n=13) and targeted sequencing and copy number analysis in additional carcinomas (n=10) and borderline tumours (n=44) identified recurrent mutations in novel drivers such as EIF1AX and USP9X, as well as the known drivers KRAS, BRAF and NRAS. Copy number changes including 9p and 1p losses were significantly associated with progression from borderline to carcinoma. Exome and targeted sequencing analysis of mucinous carcinomas (GAMuT study) found a surprisingly high proportion (~50%) with TP53 mutations, and mutations in new drivers like RNF43 and ELF3. Despite similarities in early RAS/RAF pathway oncogenic drivers and CDKN2A disruption, the genetics of these two subtypes are otherwise distinct, suggesting differing etiologies and selective pressures.

We also present here the first whole-genome sequencing analysis of a high-grade mucinous ovarian carcinoma collected from multiple sites at autopsy (CASCADE study). The patient, aged just 41 when diagnosed with Stage I mucinous ovarian carcinoma, had a 26-month progression-free interval, including normal CA125 and CA19-9 measurements at 21 months. The primary tumor was mostly borderline in appearance, with only a small focus of carcinoma. At autopsy, the carcinoma was widespread in the body, and whole-genome sequencing data was obtained from deposits in the omentum, iliac lymph node, para-aortic lymph node and upper diaphragm. These data were compared to the primary ovarian tumor and nine other sites sampled at autopsy.

Citation Format: Kylie L. Gorringe, Matthew Wakefield, Sally M. Hunter, Georgina L. Ryland, Dane Cheasley, Michael S. Anglesio, Michael Christie, Raghwa Sharma, Antill Yoland, Simone M. Rowley, Jason Li, Blake Gilks, Prue E. Allan, Andrew N. Stephens, Sumi Ananda, Jan Pyman, Martin Koebel, Jessica McAlpine, Charlie Gourley, David G. Huntsman, Anna deFazio, David DL Bowtell, Ian G. Campbell, Clare Scott. Genomics analyses of less common epithelial ovarian cancer subtypes. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr B08.

Validation of the Driver Behaviour Questionnaire in a representative sample of drivers in Australia

The Driver Behaviour Questionnaire (DBQ) is a widely used measure of driving behaviours that may increase a driver's risk of crash involvement. However, there are several different versions of the DBQ varying in terms of number of items and factor structure. The aim of the current research was to assess the construct validity of the popular 28-item four-factor DBQ solution in a representative sample of drivers in Australia. A further aim was to test the factorial invariance of the measure across gender, age and also between fleet and non-fleet drivers using multigroup confirmatory factor analyses. Data on a range of attitudes towards road safety were collected using an online survey. A stratified sampling procedure was undertaken to ensure the age, gender and location distributions of participants were representative of the Australian population. A total of 2771 responses were obtained from fully licensed motor vehicle drivers (male: 46%). Confirmatory factor analysis supported the 28-item four-factor DBQ in the Australian sample. The DBQ was also found to be gender-invariant and strong partial measurement invariance was found for drivers aged from 26 to 64, but not for younger (17-25) or older (65-75) drivers. Modifications to the DBQ suggest how the DBQ can be improved for use in these two age groups.

Identification of novel dipeptidyl peptidase 9 substrates by two-dimensional differential in-gel electrophoresis

Dipeptidyl peptidase 9 (DPP9) is a member of the S9B/DPPIV (DPP4) serine protease family, which cleaves N-terminal dipeptides at an Xaa-Pro consensus motif. Cytoplasmic DPP9 has roles in epidermal growth factor signalling and in antigen processing, whilst the role of the recently discovered nuclear form of DPP9 is unknown. Mice lacking DPP9 proteolytic activity die as neonates. We applied a modified 2D differential in-gel electrophoresis approach to identify novel DPP9 substrates, using mouse embryonic fibroblasts lacking endogenous DPP9 activity. A total of 111 potential new DPP9 substrates were identified, with nine proteins/peptides confirmed as DPP9 substrates by MALDI-TOF or immunoblotting. Moreover, we also identified the dipeptide Val-Ala as a consensus site for DPP9 cleavage that was not recognized by DPP8, suggesting different in vivo roles for these closely related enzymes. The relative kinetics for the cleavage of these nine candidate substrates by DPP9, DPP8 and DPP4 were determined. This is the first identification of DPP9 substrates from cells lacking endogenous DPP9 activity. These data greatly expand the potential roles of DPP9 and suggest different in vivo roles for DPP9 and DPP8.

EPO-receptor is present in mouse C2C12 and human primary skeletal muscle cells but EPO does not influence myogenesis

The role and regulation of the pleiotropic cytokine erythropoietin (EPO) in skeletal muscle are controversial. EPO exerts its effects by binding its specific receptor (EPO‐R), which activates intracellular signaling and gene transcription in response to internal and external stress signals. EPO is suggested to play a direct role in myogenesis via the EPO‐R, but several studies have questioned the effect of EPO treatment in muscle in vitro and in vivo. The lack of certainty surrounding the use of nonspecific EPO‐R antibodies contributes to the ambiguity of the field. Our study demonstrates that the EPO‐R gene and protein are expressed at each stage of mouse C2C12 and human skeletal muscle cell proliferation and differentiation and validates a specific antibody for the detection of the EPO‐R protein. However, in our experimental conditions, EPO treatment had no effect on mouse C2C12 and human muscle cell proliferation, differentiation, protein synthesis or EPO‐R expression. While an increase in Akt and MAPK phosphorylation was observed, we demonstrate that this effect resulted from the stress caused by changing medium and not from EPO treatment. We therefore suggest that skeletal muscle EPO‐R might be present in a nonfunctional form, or too lowly expressed to play a role in muscle cell function.

The EPO‐R is expressed at the gene and protein level in mouse and human myoblasts and myotubes. However, EPO treatment does not seem to activate the EPO‐R and its downstream signaling pathways in skeletal muscle cells, questioning its functionality.

A streamlined approach to high-throughput proteomics

Proteomics has rapidly become an important tool for life science research, allowing the integrated analysis of global protein expression from a single experiment. To accommodate the complexity and dynamic nature of any proteome, researchers must use a combination of disparate protein biochemistry techniques, often a highly involved and time-consuming process. Whilst highly sophisticated, individual technologies for each step in studying a proteome are available, true high-throughput proteomics that provides a high degree of reproducibility and sensitivity has been difficult to achieve. The development of high-throughput proteomic platforms, encompassing all aspects of proteome analysis and integrated with genomics and bioinformatics technology, therefore represents a crucial step for the advancement of proteomics research. ProteomIQ (Proteome Systems) is the first fully integrated, start-to-finish proteomics platform to enter the market. Sample preparation and tracking, centralized data acquisition and instrument control, and direct interfacing with genomics and bioinformatics databases are combined into a single suite of integrated hardware and software tools, facilitating high reproducibility and rapid turnaround times. This review will highlight some features of ProteomIQ, with particular emphasis on the analysis of proteins separated by 2D polyacrylamide gel electrophoresis.