Abstract A015: Protein arginine deiminase enzymes which citrullinate epitopes for MHC II presentation are independent predictors of survival in colorectal cancer

Citrullination of proteins is associated with a number of autoimmune diseases. Protein Arginine Deiminases (PADs) are a family of Ca2+ dependent enzymes that under cellular stress post-translationally convert arginine to citrulline within protein substrates to generate self-modified neo-antigens. It has been shown that presentation of citrullinated peptides on MHC class II stimulates CD4 T cells to mediate potent anti-tumor immunity (1). In this study we focus on the role of the PADI2 and PADI4 family members in colorectal cancer. Using a tissue microarray of colorectal cancers and compiling a comprehensive database of clinicopathological variables, the expression of PADI2 and PADI4 was assessed by immunohistochemistry in a study cohort. This data was used to correlate PADI2 and PADI4 expression with patient survival.

In the study cohort 462 colorectal tumors were stained for PADI2 and PADI4. Of these 171 (37%) and 231 (50%) could not be evaluated for PADI2 and PADI4 staining respectively due to the absence of enough tissue core or no evaluable tumor cells (i.e. all stroma) in the core. Of the 291 evaluable colorectal tumors stained with a PADI2 specific antibody, only 18/291 (6.2%) tumors failed to stain. A further 153/291 (52.5%) stained weakly, 102/291 (35.1%) moderate and 18/291 (6.2%) stained strongly. Of the 231 evaluable colorectal tumors stained with a PADI4 specific antibody, no tumors failed to stain. All cases stained strongly for PADI4 expression within the nucleus. In the cytoplasm 63/231 (27.3%) stained weakly, 143/231 (61.9%) moderate and 25/231 (10.8%) stained strongly.

PADI2 expression did not correlate with any clinicopathological variables whereas nuclear but not cytoplasmic PADI4 showed a strong association with histological type (p = 0.008). Kaplan-Meier analysis showed there was a correlation of PADI2 and cytoplasmic PADI4 expression with improved survival. Expression of PADI2 gave an increase in survival time from 44.8 months (95% CI 24.3 to 65.4) to 76.2 months (95% CI 69.9 to 82.4, log rank test, p = 0.012). Expression of cytoplasmic PADI4 increased survival time from 57.9 months (95% CI 43.6 to 72.3) to 77.3 months (95% CI 69.6 to 85.1, log rank test, p = 0.012). No significant correlation was observed between PADI2 and the cytoskeletal protein Vimentin or the glycolytic enzyme α-enolase both reported to be citrullinated by PAD enzymes. PADI2 expression was significantly associated with expression of the Nuclear antigen Ki67 (p = 0.046) a cellular marker for proliferation. Nuclear PADI4 significantly correlated with the cytoplasmic glycolytic enzyme α-enolase only (p = 0.001) and cytoplasmic PADI4 was highly significantly associated with α-enolase located in both the cytoplasm (p<0.001) and shorter nuclear form (p<0.001) known as MBP-1, a transcription factor known to downregulate the activity of the c-myc proto-oncogene. Cytoplasmic PADI4 expression also significantly correlated with expression of the anti-apoptotic protein Bcl2 (p = 0.028). Multivariate analysis using Cox regression showed that PADI2 (p = 0.040)/Cytoplasmic PADI4 (p = 0.036), the stress related protein MICA (p = 0.006/0.022), vascular invasion (p<0.001, 0.040) and tumor stage (p<0.001/<0.001) are all independent markers of good prognosis in colorectal cancer. These results are consistent with the hypothesis that stressed tumor cells present citrullinated epitopes allowing their growth to be controlled by T cells.

References

1. Brentville VA, Metheringham RL, Gunn B, Symonds P, Daniels I, Gijon M, Cook K, Xue W, Durrant LG (2016). Citrullinated vimentin presented on MHC-II in tumor cells is a target for CD4+ T cell-mediated antitumor immunity. Cancer Research 2016 Feb 1;76(3):548-60

Citation Format: R. Metheringham, M. Gijon, I. Daniels, K. Cook, P. Symonds, T. Pitt, W. Xue, V. Brentville, L. Durrant. Protein arginine deiminase enzymes which citrullinate epitopes for MHC II presentation are independent predictors of survival in colorectal cancer [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A015.

[Value of perineural invasion in prostatectomy specimen in the assessment on tumor progression and prognosis]

OBJECTIVE

To assess perineural invasion in prostatectomy specimen(PNIp)on tumor progression and prognosis after radical prostatectomy.

METHODS

Retrospective analysis including 502 prostate cancer patients admitted in Renji Hospital, School of Medicine, Shanghai Jiaotong University from December 2002 to May 2014 was studied.Differences of serum prostate specific antigen(PSA), Gleason score of prostate biopsy, Gleason score of prostatectomy specimen, tumor stage, capsular invasion, positive surgical margin, seminal invasion, pelvic lymph node metastasis, nadir PSA were analyzed in patients with PNIp and without PNIp. Logistic regression analysis, Log-rank test and Cox regression analysis was used to analyzed the data, respectively.

RESULTS

There were 91 patients with PNIp(18.1%) and 411 patients without PNIp(81.9%). Differences of serum PSA, Gleason score of prostate biopsy, Gleason score of prostatectomy specimen, tumor stage, capsular invasion, seminal invasion, nadir PSA between the two groups were found(all P<0.05). In the multivariable logistic regression analysis, PNIp was independent predictor of Gleason score of prostate biopsy, Gleason score of prostatectomy specimen, tumor stage, capsular invasion(OR=1.515, 1.955, 2.069, 1.859, all P<0.05). One hundred and twenty-one patients with biochemical serum recurrence(26.7%). Serum PSA, Gleason score of prostate biopsy, Gleason score of prostatectomy specimen, tumor stage, PNIp, seminal invasion were related to biochemical serum recurrence(P<0.05). In the multivariable cox regression analysis, serum PSA, Gleason score of prostate biopsy, PNIp, seminal invasion were independent predictors of biochemical serum recurrence(HR=1.021, 1.441, 1.663, 3.257, all P<0.05).

CONCLUSION

PNIp is the important predictor of the tumor progression and prognosis of prostate cancer.

Pretreatment plasma fibrinogen as an independent prognostic indicator of prostate cancer patients treated with androgen deprivation therapy

BACKGROUND

Hyperfibrinogen is thought to be associated with a higher risk of invasion and metastasis, as well as a worse outcome for multiple types of cancer. However, the prognostic significance of plasma fibrinogen has not been investigated in prostate cancer with hormonal therapy. The objective of this study was to evaluate its roles in prostate cancer patients treated with androgen deprivation therapy (ADT).

METHODS

A total of 290 patients who underwent ADT as first-line therapy for prostate cancer were retrospectively analyzed. The fibrinogen level was measured at the time of diagnosis. Patients were categorized using a cutoff point of 3.225 g l(-1) according to a calculation by the receiver operating curve analysis. Correlations between the fibrinogen and clinical characteristics were analyzed. Meanwhile, univariable and multivariable cox regression analyses were performed to determine the associations of fibrinogen with progression-free survival (PFS), cancer-specific survival (CSS) and overall survival (OS). Prognostic accuracy was evaluated with the Harrell concordance index.

RESULTS

Compared with patients with a lower fibrinogen level (<3.225 g l(-1)), patients with a higher fibrinogen level were more likely to have higher PSA, Gleason score, risk stratification and incidence of metastasis (P<0.05). Multivariable analyses identified hyperfibrinogen as an independent prognostic factor for PFS (hazard ratio (HR)=2.000, P<0.001), CSS (HR=2.209, P=0.006) and OS (HR=1.965, P=0.009). The final models built by the addition of fibrinogen improved predictive accuracy (c-index: 0.750, 0.799 and 0.767) for PFS, CSS and OS compared with the clinicopathological base models (c-index: 0.730, 0.778 and 0.746), which included Gleason score and metastasis.

CONCLUSIONS

The pretreatment plasma fibrinogen level was associated with tumor progression and might have a significant role in the prognosis of the prostate cancer patients treated with ADT. Thus, we recommend adding fibrinogen to traditional prognostic model, which may improve its predictive accuracy.

EDA mutation as a cause of hypohidrotic ectodermal dysplasia: a case report and review of the literature

Ectodermal dysplasia (ED) represents a collection of rare disorders that result from a failure of development of the tissues derived from the embryonic ectoderm. ED is often associated with hair, teeth, and skin abnormalities, which are serious conditions affecting the quality of life of the patient. To date, a large number of genes have been found to be associated with this syndrome. Here, we report a patient with hypohidrotic ED (HED) without family history. We identified that this patient's disorder arises from an X-linked HED with a mutation in the EDA gene (G299D) found by whole-exome sequencing. In addition, in this paper we summarize the disease-causing mutations based on current literature. Overall, recent clinical and genetic research involving patients with HED have uncovered a large number of pathogenic mutations in EDA, which might contribute to a full understanding of the function of EDA and the underlying mechanisms of HED caused by EDA mutations.

Bupivacaine inhibits endothelin-1-evoked increases in intracellular calcium in model sensory neurons

BACKGROUND

Endothelin-1 (ET-1) induces pain-like behavior in animals and man by activating the Gq protein-coupled receptor endothelin-A (ETA ). Activation of ETA receptors on nociceptor membranes evokes intracellular calcium transients and alters membrane Na(+) and K(+) channel and TRPV1 currents, leading to neuronal hyper-excitability manifested by spontaneous and evoked pain behaviors in vivo. In addition to blocking sodium channels, local anesthetics inhibit the Gq protein-coupled signaling of several inflammatory and pro-algesic mediators. In this study, we aimed to investigate the actions of local anesthetics on ETA -mediated increases in intracellular calcium in ND7/104 model sensory neurons.

METHODS

Increases in intracellular calcium were measured by the fluorescent indicator fura-2 in a sensory neuron-derived cell line (ND7/104), which endogenously expresses ETA receptors. Effects of lidocaine and bupivacaine, along with their respective membrane-impermeant derivatives QX-314, LEA-123 and LEA-124, on peak calcium responses to ET-1 were measured.

RESULTS

Bupivacaine suppressed ET-1 responses in a concentration-dependent and non-competitive manner with an IC50 of 3.79 ± 1.63 mM. Bupivacaine (6 mM) reduced the Emax for ET-1 from 50.07 ± 1.91 mM to 27.30 ± 2.92 mM. The actions of bupivacaine occurred quickly and were rapidly reversible. Membrane-impermeant analogs of bupivacaine (LEA-123 and LEA-124, 6 mM) were without effect, as was lidocaine (10 mM) and its quaternary derivative QX-314 (10 mM).

CONCLUSION

Bupivacaine inhibits ETA -mediated calcium transients at clinically relevant concentrations through an intracellular target. The anti-inflammatory and analgesic actions of bupivacaine may be at least partially due to its inhibitory action on Gq -coupled receptors, including ETA.

Which is more suitable for kidney transplantation at the early post-transplantation phase in China - low dosing or standard dosing of enteric-coated mycophenolate sodium?

AIMS

To investigate the pharmacokinetics of enteric-coated mycophenolate sodium (EC-MPS) and the clinical outcome in kidney transplant recipients in the early post-transplantation phase. Then explain which regimen is more suitable for Chinese renal transplant recipients.

METHODOLOGY

In total, 60 de novo kidney transplant recipients treated with tacrolimus and steroids were randomised to receive EC-MPS at standard dose (SD; 1440 mg/day; n = 28) or low dose (LD; 1080 mg/day; n = 32). Efficacy parameters, safety and tolerability were assessed over a 6-month study period. Full mycophenolic acid (MPA) areas under the curve (AUCs) were completed on days 3 and 5, whereas a three-point limited sampling strategy (LSS) was utilised for MPA AUC assessments at 2 weeks and months 1, 3 and 6 (the LSS for three-time-point MPA AUC 0-12 h (mg h/l) = 15.99 + 0.87C1 h  + 0.68C2 h  + 7.85C4 h ; r(2)  = 0.8670.

RESULTS

The mean AUC levels at day 3 and day 5 in the SD group were significantly higher than in the LD group (57.4 mg·h/l vs. 38.2 mg·h/l and 59.3 mg·h/l vs. 44.8 mg·h/l, respectively, p < 0.01). There was a trend for fewer clinically diagnosed acute rejections in the SD group vs. the LD group at 6 months (7.1% vs. 12.5%). This trend was also present when acute rejection was analysed as biopsy-proven cases. There were significantly more acute rejections (all definitions) in patients with MPA AUC levels < 30 mg·h/l compared with those with MPA AUC levels ≥ 30 mg·h/l within 6 months (p < 0.05). Renal function, incidence of infection and haematological disorders were not significantly different in either study group.

CONCLUSIONS

Early adequate MPA exposure in renal transplant recipients can be achieved with a higher starting dose. In addition, a SD regimen was as well-tolerated as a LD regimen. Furthermore, early adequate MPA exposure significantly lowered the rate of acute rejection without compromising safety and tolerability.

Effects of clonal fragmentation on intraspecific competition of a stoloniferous floating plant

Disturbance is common and can fragment clones of plants. Clonal fragmentation may affect the density and growth of ramets so that it could alter intraspecific competition. To test this hypothesis, we grew one (low density), five (medium density) or nine (high density) parent ramets of the floating invasive plant Pistia stratiotes in buckets, and newly produced offspring ramets were either severed (with fragmentation) or remained connected to parent ramets (no fragmentation). Increasing density reduced biomass of the whole clone (i.e. parent ramet plus its offspring ramets), showing intense intraspecific competition. Fragmentation decreased biomass of offspring ramets, but increased biomass of parent ramets and the whole clone, suggesting significant resource translocation from parent to offspring ramets when clones were not fragmented. There was no interaction effect of density x fragmentation on biomass of the whole clone, and fragmentation did not affect competition intensity index. We conclude that clonal fragmentation does not alter intraspecific competition between clones of P. stratiotes, but increases biomass production of the whole clone. Thus, fragmentation may contribute to its interspecific competitive ability and invasiveness, and intentional fragmentation should not be recommended as a measure to stop the rapid growth of this invasive species.

Aging is associated with increased HbA1c levels, independently of glucose levels and insulin resistance, and also with decreased HbA1c diagnostic specificity

AIM

To determine whether using HbA1c for screening and management could be confounded by age differences, whether age effects can be explained by unrecognized diabetes and prediabetes, insulin resistance or postprandial hyperglycaemia, and whether the effects of aging have an impact on diagnostic accuracy.

METHODS

We conducted a cross-sectional analysis in adults without known diabetes in the Screening for Impaired Glucose Tolerance (SIGT) study 2005-2008 (n=1573) and the National Health and Nutrition Examination Survey (NHANES) 2005-2006 (n=1184).

RESULTS

Both glucose intolerance and HbA(1c) levels increased with age. In univariate analyses including all subjects, HbA(1c) levels increased by 0.93 mmol/mol (0.085%) per 10 years of age in the SIGT study and by 1.03 mmol/mol (0.094%) per 10 years in the NHANES; in both datasets, the HbA(1c) increase was 0.87 mmol/mol (0.08%) per 10 years in subjects without diabetes, and 0.76 mmol/mol (0.07%) per 10 years in subjects with normal glucose tolerance, all P<0.001. In multivariate analyses of subjects with normal glucose tolerance, the relationship between age and HbA(1c) remained significant (P<0.001) after adjustment for covariates including race, BMI, waist circumference, sagittal abdominal diameter, triglyceride/HDL ratio, and fasting and 2-h plasma glucose and other glucose levels, as assessed by an oral glucose tolerance test. In both datasets, the HbA(1c) of an 80-year-old individual with normal glucose tolerance would be 3.82 mmol/mol (0.35%) greater than that of a 30-year-old with normal glucose tolerance, a difference that is clinically significant. Moreover, the specificity of HbA(1c) -based diagnostic criteria for prediabetes decreased substantially with increasing age (P<0.0001).

CONCLUSIONS

In two large datasets, using different methods to measure HbA(1c), the association of age with higher HbA(1c) levels: was consistent and similar; was both statistically and clinically significant; was unexplained by features of aging; and reduced diagnostic specificity. Age should be taken into consideration when using HbA(1c) for the diagnosis and management of diabetes and prediabetes.

Comparative analyses of histone H3K9 trimethylations in the heart and spleen of normal humans

The global features of trimethylations of histone 3 at lysine 9 (H3K9me3) have been well studied in recent years; however, most of these studies were performed in mammalian cell lines. In this study, we generated genome-wide maps of H3K9me3 of the human heart and spleen using chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) technology. We examined the global patterns of H3K9me3 in both tissues and found that modifications were closely associated with tissue-specific expression, function, and development. In addition, we found that 169 genes displayed significant H3K9me3 differences between the heart and spleen. Among these genes, 64 were heart-H3K9me3-specific, 87 genes were spleen-H3K9me3-specific, and 18 were shared in both heart- and spleen-H3K9me3. In conclusion, we observed significant differences in H3K9me3 in the heart and spleen, which may help to explain epigenetic differences between these tissues. Such novel findings highlight the significance of H3K9me3 as a potential biomarker or promising target for epigenetic-based disease treatment.

Tropomyosin from tilapia (Oreochromis mossambicus) as an allergen

BACKGROUND

Tilapia is among the most common fresh water fish species raised by fish farms and can cause allergic reactions upon ingestion.

OBJECTIVE

To investigate important allergens in Tilapia (Oreochromis mossambicus).

METHODS

Allergens were detected using immunoblotting. An important allergen was purified to homogeneity by reversed-phase High Pressure Liquid Chromatography and characterized by enzyme linked immunosorbent assay (ELISA), competitive ELISA, Mass spectrometry (MS), circular dichroism measurements and differential scanning calorimetry.

RESULTS

By immunoblotting using sera from 10 patients with confirmed tilapia allergy, we identified a number of allergens with apparent molecular weights 114 to 17 kD. All patients produced IgE against a 32 kD allergen, Ore m 4, which was identified by MS as tropomyosin (TM). IgE binding of the pure protein was confirmed by immunoblotting, ELISA and ELISA inhibition. cDNA from tilapia tropomyosin (TM) was sequenced and compared with TMs from other species. The tilapia TM showed 53.5% homology to TM from shrimp. Homology was much higher to human TM isoform 5 (87.7%).

CONCLUSION AND CLINICAL RELEVANCE

TMs are the major allergens in allergy to crustaceans. Auto-antibodies against human TM isoform 5 have been implicated as a causative agent in inflammatory bowel disease (IBD). Intriguingly, six of the 10 tilapia allergic patients had also been diagnosed with IBD, corroborating a connection between allergy and IBD. To our knowledge, this is the first report of tropomyosin from vertebrates as an allergen.

Novel EDA p.Ile260Ser mutation linked to non-syndromic hypodontia

Hypodontia, a tooth developmental disease, can affect chewing and pronunciation. Mutations in the ectodysplasin-A (EDA) gene can lead to both X-linked hypohidrotic ectodermal dysplasia (XLHED) and non-syndromic hypodontia (NSH). However, the mechanism by which these 2 related but different disorders are caused by the distinct mutations in EDA is unknown. In this study, we identified a novel missense mutation (c.779 T>G) in a Chinese family with NSH via a direct sequencing approach. This mutation results in an Ile260Ser substitution in the tumor necrosis factor (TNF) homology domain. Homology modeling suggests that this alteration may induce a conformational change in the hydrophobic center of the TNF homology domain. Furthermore, by exploring systematic 3D conformation analysis and calculation of residue relative solvent accessibility (RSA) for all the reported mutated amino acid sites on EDA's TNF homology domain, we found that the site mutations at the interior may be linked to XLHED, while those at the surface are more likely to be associated with NSH. These findings may aid in the discovery of unidentified functionally significant mutation sites in the EDA gene and provide a new way to clarify the mechanisms by which the XLHED and NSH phenotypes arise from mutations in the same gene.

The feasibility of using magnetic nanoparticles modified as gene vector

OBJECTIVE

To evaluate the feasibility of using magnetic nanoparticles (MNPs) as gene vector and the effect of magnetic field on efficiency of transfection.

METHODS

Magnetic nanoparticles were prepared by controlling some chemical reaction parameters through a partially reduction precipitation method with ferric chloride aqueous solution as precursor material. The surface of particles was modified by polyethyleneimine (PEI) agents. The appearance, the size distribution, structure and phase constitute of MNPs were characterized by Transmission electron microscope (TEM), X-ray diffraction (XRD); the potential of absorbing DNA of MNPs was analysed by electrophoresis. Transfection was determined by delivering reporter gene, PGL2-control encoding luciferase, to different cell lines using MNPs-PLL as vector. The effect of magnetic field on the efficiency of transfection was determined using Nd-Fe-B permanent magnet.

RESULTS

Foreign gene could be delivered to various cell lines by MNPs-PLL and expressed with high efficiency but the transfection efficiency and time course varied in the different cell lines studied. Magnetic field could enhance the efficiency of transfection by 5-10 fold.

CONCLUSION

MNPs- PLL can be used as a novel non-viral gene vector in vitro, which offers a basis for gene delivery in vivo.