Abstract C084: Oncogenic KRAS signaling drives the activation of tissue-resident fibroblasts and is required to maintain CAF heterogeneity in pancreatic cancer

The complexity of the tumor microenvironment (TME) is one of the distinguishing features of pancreatic ductal adenocarcinoma (PDA) and is responsible for patients’ poor response to therapies. The heterogeneity of cancer-associated fibroblasts (CAFs) has been correlated to the key features of the stroma that contribute to making PDA the third-leading cause of cancer-related deaths in the United States. The recent development of FDA-approved drugs against oncogenic KRAS opened a new therapeutic avenue for the treatment of tumors that have KRAS as their driver oncogene, such as PDA. However, the precise mechanisms driving the development of the TME and the contribution of KRAS to these processes have yet to be elucidated. This poses a challenge for the prediction of the effects of KRAS inhibition on established PDA tumors. By employing spatial transcriptomic technologies on various murine models recapitulating different stages of tumor initiation and progression, from acute and chronic inflammation to PanIN and overt PDA, we were able to observe distinctive changes in the activation status of pancreatic fibroblasts. These resident activated fibroblasts (RAFs) display expression of discrete markers brought upon by inflammation (inflammatory RAFs, iRAFs) or specific to oncogenic KRAS activation (myofibroblastic RAFs, myRAFs). Importantly, these RAF populations are maintained in established tumors and are identifiable in human PDA. To assess the consequences of the disruption of KRAS signaling on CAFs and RAFs, we employed a PDA mouse model that allows for the irreversible excision of KrasG12V, the FPC model (KrasFrt-LSL-G12V-Frt; p53LSL-R172H; PDX-CRE; Rosa26FlpOERT2). Through a combination of single-cell RNA sequencing (scRNA-seq), spatial transcriptomics and fluorescent in situ hybridization combined with immunofluorescence (immunoFISH) on FPC mice before and after KrasG12V deletion, we demonstrate the profound impact of Kras ablation on the TME composition. A deep remodeling of the stroma as well as significant changes in the proportion of CAF subtypes were evident. Interestingly, we observed a decrease in CAFs with a concomitant increase in RAFs. Our results suggest that the activation of oncogenic Kras in pre-neoplastic lesions drives a unique paracrine signaling that shapes the TME and is required to maintain the CAF population in PDA.

Citation Format: Giuseppina Caligiuri, Jennifer S. Thalappillil, Mojdeh Shakiba, Sandeep Nadella, Juliene Hinds, Elise Courtois, William F. Flynn, Brinda Alagesan, Georgi N. Yordanov, Benjamin Kaminow, Paul Robson, Pedro A. Perez-Mancera, Jonathan Preall, Alexander Dobin, Youngku Park, David A. Tuveson. Oncogenic KRAS signaling drives the activation of tissue-resident fibroblasts and is required to maintain CAF heterogeneity in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C084.

Does Gadolinium Deposition Lead to Metabolite Alteration in the Dentate Nucleus? An MRS Study in Patients with MS

BACKGROUND AND PURPOSE

Repeat contrast-enhanced MR imaging exposes patients with relapsing-remitting MS to frequent administration of gadolinium-based contrast agents. We aimed to investigate the potential metabolite and neurochemical alterations of visible gadolinium deposition on unenhanced T1WI in the dentate nucleus using MRS.

MATERIALS AND METHODS

This prospective study was conducted in a referral university hospital from January 2020 to July 2021. The inclusion criteria for case and control groups were as follows: 1) case: patients with relapsing-remitting MS, visible gadolinium deposition in the dentate nucleus (ribbon sign), >5 contrast-enhanced MR images obtained; 2) control 1: patients with relapsing-remitting MS without visible gadolinium deposition in the dentate nucleus, >5 contrast-enhanced MR images obtained; 3) control 2: patients with relapsing-remitting MS without visible gadolinium deposition in the dentate nucleus, <5 contrast-enhanced-MR images obtained; and 4) control 3: adult healthy individuals, with no contrast-enhanced MR imaging. Dentate nucleus and pontine single-voxel 12 × 12 × 12 MRS were analyzed using short TEs.

RESULTS

Forty participants (10 per group; 27 [67.5%] female; mean age, 35.6 [SD, 9.6] years) were enrolled. We did not detect any significant alteration in the levels of NAA and choline between the studied groups. The mean concentrations of mIns were 2.7 (SD, 0.73) (case), 1.5 (SD, 0.8) (control 1), 2.4 (SD, 1.2) (control 2), and 1.7 (SD, 1.2) (control 3) (P = .04). The mean concentration of Cr and mIns (P = .04) and the relative metabolic concentration (dentate nucleus/pons) of lipid 1.3/Cr (P = .04) were significantly higher in the case-group than in healthy individuals (controls 1-3). Further analyses compared the case group with cumulative control 1 and 2 groups and showed a significant increase in lactate (P = .02), lactate/Cr (P = .04), and Cr (dentate nucleus/pons) (P = .03) in the case group.

CONCLUSIONS

Although elevated concentrations of Cr, lactate, mIns, and lipid in the dentate nucleus of the case group indicate a metabolic disturbance, NAA and choline levels were normal, implying no definite neuronal damage.

Abstract 3647: Oncogenic Kras drives cancer-associated fibroblast heterogeneity and substate changes in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is currently the third-leading cause of cancer-related deaths in the United States with no effective or targeted therapies to improve outcomes. Two defining features of PDAC are the dense stroma composing the bulk of the tumor mass and mutations in KRAS, the primary oncogene in most PDAC patients. Advances in knowledge on both fronts have led to promising avenues for therapeutics: recently described heterogeneity within the cancer-associated fibroblast (CAF) population residing in the stroma offers insight into the lack of success with therapies only targeting CAFs; and mutant KRAS inhibitors directed at the G12C isoform have received accelerated FDA approval for treatment of locally advanced and metastatic non-small cell lung cancer. However, the nature of this CAF heterogeneity is not yet fully understood, and any effects of KRAS blockade on the stroma have not been evaluated with consideration of this heterogeneity in mind. To assess how loss of Kras affects CAF heterogeneity and plasticity, we employed a genetically engineered mouse model (GEMM) of PDAC harboring a reversible oncogenic KrasG12V allele conditionally expressed from the endogenous Kras locus. This FPC compound mouse (KrasFrt-LSL-G12V-Frt; p53LSL-R172H; PDX-CRE; Rosa26FlpOERT2) spontaneously develops pancreatic lesions and allows for irreversible excision of the mutant Kras allele upon the application of Tamoxifen. Using single-cell RNA sequencing (scRNAseq), fluorescence in situ hybridization, and functional in vitro and in vivo approaches, we found that oncogenic Kras ablation led to tumor regression and altered cancer cell gene programs, profoundly affecting the tumor microenvironment, specifically CAF heterogeneity. Mutant Kras loss leads to decreased Tgfb1 expression in the cancer cells, but surprisingly also to increased Il1a levels, correlating with a reduction in myofibroblastic CAFs (myCAFs) and an expansion in inflammatory CAFs (iCAFs), respectively. Our results suggest that mutant Kras drives paracrine signaling that shapes CAF heterogeneity and should be considered for the development of the most effective therapeutic strategies.

Citation Format: Jennifer S. Thalappillil, Giuseppina Caligiuri, Sandeep Nadella, Brinda Alagesan, Georgi N. Yordanov, Mojdeh Shakiba, Benjamin Kaminow, Juliene Hinds, Pedro A. Perez-Mancera, Jonathan Preall, Alexander Dobin, Youngkyu Park, David A. Tuveson. Oncogenic Kras drives cancer-associated fibroblast heterogeneity and substate changes in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3647.

Ketohexokinase-mediated fructose metabolism is lost in hepatocellular carcinoma and can be leveraged for metabolic imaging

The ability to break down fructose is dependent on ketohexokinase (KHK) that phosphorylates fructose to fructose-1-phosphate (F1P). We show that KHK expression is tightly controlled and limited to a small number of organs and is down-regulated in liver and intestinal cancer cells. Loss of fructose metabolism is also apparent in hepatocellular adenoma and carcinoma (HCC) patient samples. KHK overexpression in liver cancer cells results in decreased fructose flux through glycolysis. We then developed a strategy to detect this metabolic switch in vivo using hyperpolarized magnetic resonance spectroscopy. Uniformly deuterating [2-13C]-fructose and dissolving in D2O increased its spin-lattice relaxation time (T1) fivefold, enabling detection of F1P and its loss in models of HCC. In summary, we posit that in the liver, fructolysis to F1P is lost in the development of cancer and can be used as a biomarker of tissue function in the clinic using metabolic imaging.

TCR signal strength defines distinct mechanisms of T cell dysfunction and cancer evasion

T cell receptor (TCR) signal strength is a key determinant of T cell responses. We developed a cancer mouse model in which tumor-specific CD8 T cells (TST cells) encounter tumor antigens with varying TCR signal strength. High-signal-strength interactions caused TST cells to up-regulate inhibitory receptors (IRs), lose effector function, and establish a dysfunction-associated molecular program. TST cells undergoing low-signal-strength interactions also up-regulated IRs, including PD1, but retained a cell-intrinsic functional state. Surprisingly, neither high- nor low-signal-strength interactions led to tumor control in vivo, revealing two distinct mechanisms by which PD1hi TST cells permit tumor escape; high signal strength drives dysfunction, while low signal strength results in functional inertness, where the signal strength is too low to mediate effective cancer cell killing by functional TST cells. CRISPR-Cas9-mediated fine-tuning of signal strength to an intermediate range improved anti-tumor activity in vivo. Our study defines the role of TCR signal strength in TST cell function, with important implications for T cell-based cancer immunotherapies.

Prevalence of asymptomatic COVID-19 infection using a seroepidemiological survey

The prevalence of asymptomatic infection by coronavirus disease 2019 (COVID-19) as a critical measure for effectiveness of mitigation strategy has been reported to be widely varied. In this study, we aimed to determine the prevalence of asymptomatic infection using serosurvey on general population. In a cross-sectional seroprevalence survey in Guilan province, Iran, the specific antibody against COVID-19 in a representative sample was detected using rapid test kits. Among 117 seropositive subjects, prevalence of asymptomatic infection was determined based on the history of symptoms during the preceding 3 months. The design-adjusted prevalence of asymptomatic infection was 57.2% (95% confidence interval (CI) 44-69). The prevalence was significantly lower in subjects with previous contacts to COVID-19 patients (12%, 95% CI 2-49) than others without (69%, 95% CI, 46-86). The lowest prevalence was for painful body symptom (74.4%). This study revealed that more than half of the infected COVID-19 patients had no symptoms. The implications of our findings include the importance of adopting public health measures such as social distancing and inefficiency of contact tracing to interrupt epidemic transmission.

TOX is a critical regulator of tumour-specific T cell differentiation

Tumour-specific CD8 T cell dysfunction is a differentiation state that is distinct from the functional effector or memory T cell states^1–6. Here we identify the nuclear factor TOX as a crucial regulator of the differentiation of tumour-specific T (TST) cells. We show that TOX is highly expressed in dysfunctional TST cells from tumours and in exhausted T cells during chronic viral infection. Expression of TOX is driven by chronic T cell receptor stimulation and NFAT activation. Ectopic expression of TOX in effector T cells in vitro induced a transcriptional program associated with T cell exhaustion. Conversely, deletion of Tox in TST cells in tumours abrogated the exhaustion program: Tox-deleted TST cells did not upregulate genes for inhibitory receptors (such as Pdcd1, Entpd1, Havcr2, Cd244 and Tigit), the chromatin of which remained largely inaccessible, and retained high expression of transcription factors such as TCF-1. Despite their normal, ‘non-exhausted’ immunophenotype, Tox-deleted TST cells remained dysfunctional, which suggests that the regulation of expression of inhibitory receptors is uncoupled from the loss of effector function. Notably, although Tox-deleted CD8 T cells differentiated normally to effector and memory states in response to acute infection, Tox-deleted TST cells failed to persist in tumours. We hypothesize that the TOX-induced exhaustion program serves to prevent the overstimulation of T cells and activation-induced cell death in settings of chronic antigen stimulation such as cancer.

Abstract A217: TCR affinity determines the fate of T-cells in tumors

T-cell-mediated immune responses are triggered by T-cell receptor (TCR) binding to peptide-major histocompatibility complex (pMHC). In acute infections, affinity of TCR:pMHC interaction is a critical determinant of T-cell expansion and effector function. However, little is known about how tumor (neo) antigen affinity impacts T-cell differentiation and dysfunction in tumors. To investigate the functional and molecular programs determined by affinity, we generated an in vivo tumor model expressing altered peptide ligands (APL) derived from a native tumor neoantigen recognized by antigen-specific CD8 T-cells with varying functional avidity. While affinity did not impact T-cell activation in tumor draining lymph nodes, it drove distinct functional and molecular pathways at the tumor site: key transcription factors and effector molecules were regulated by signal strength, preserving a cell-intrinsic functional program in T-cells with lower-affinity interactions, while certain hallmarks of T-cell dysfunction, including the expression of some inhibitory receptors, were affinity-independent. RNAseq and ATACseq analyses revealed distinct affinity-dependent transcriptional and epigenetic programs in low- vs. high-affinity T-cells that drive their functional differences. Together these results reveal that TCR:pMHC affinity plays a critical role in defining the epigenetic and transcriptional states and ultimately fate of tumor-specific T-cells.

Citation Format: Mojdeh Shakiba. TCR affinity determines the fate of T-cells in tumors [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A217.

Motivational interviewing-based training vs traditional training on the uptake of cervical screening: a quasi-experimental study

OBJECTIVES

Cervical cancer, a major health issue affecting women, is preventable and can be successfully treated. It is essential that measures are taken to improve the uptake of screening for this cancer. The aim of this study was to compare the effects of motivational interviewing (MI)-based training and traditional training on the frequency of cervical cancer screening tests in a group of working female teachers.

STUDY DESIGN

This is a quasi-experimental study.

METHODS

This research was conducted in 2017 among 134 teachers (aged 30-60 years) working in southeastern Iran. The participants were selected from among the eligible individuals and subsequently divided into MI-based training and traditional training groups (n = 67 for each group). Each group received a three-session training program, and 20 weeks after the end of the last training session, the information obtained from cervical cancer screening tests was documented. To analyze the data, independent t-test and Chi-squared test were run in SPSS, version 21.

RESULTS

There was no significant difference between the two groups in terms of demographic characteristics such as age, age at the first pregnancy, age of marriage, the number of parities, and educational level. Twenty weeks after intervention, 20.9% of the MI-based training group underwent Pap smear screening test, while 9% of the women in the traditional training group took the test, indicating a statistically significant difference between the two groups (P < 0.0.5).

CONCLUSION

MI-based training has a significant positive effect on women's compliance with cervical cancer screening tests. Therefore, it is recommended that this technique be adopted in women's health centers.

TRIAL REGISTRATION NUMBER

IRCT2017100729954N4.

The role of thymocyte selection-associated HMG box protein (TOX) in CD8 T cell differentiation and dysfunction

CD8 T cells are powerful adaptive immune cells that specifically recognize infected cells and eliminate them. However, in the context of tumors, antigen-specific T cells enter a state of dysfunction allowing tumors to progress. By employing genome-wide transcriptome analysis of dysfunctional tumor-specific T cells (TST) we found that a nuclear factor, thymocyte selection-associated HMG box protein (TOX), was uniquely upregulated during T cell differentiation/dysfunction in progressing tumors, but not during normal CD8 T cell differentiation (e.g. acute infections). TOX is a nuclear DNA-binding factor and member of the high-motility group box superfamily. TOX has been shown to be required for CD4 T cell and NK cell development but its role in peripheral CD8 T cells is not known. We set out to investigate the role of TOX in tumor-specific CD8 T cell differentiation. Using various murine tumor models we found that TOX was uniquely overexpressed in TST within the tumor (TIL) and its overexpression was driven by chronic TCR/antigen stimulation and not by the tumor microenvironment. To understand the role of TOX in CD8 T cell differentiation and dysfunction we are currently conducting TOX genetic knock-out and overexpression studies in vitro and in vivo. The identification and characterization of novel transcriptional regulators such as TOX will provide important insights into the molecular underpinnings defining CD8 T cell dysfunction in tumors.

The impact of TCR affinity on T cell differentiation and dysfunction in tumors

Although tumor-specific CD8 T cells are found in human tumors, cancers progress, indicating that these T cells are dysfunctional; yet the regulatory mechanisms underlying tumor-specific T cell dysfunction remain poorly defined. T cell-mediated immune responses are triggered by T cell receptor (TCR) binding to peptide-major histocompatibility complex (pMHC). In acute infections, affinity of TCR:pMHC interaction is a critical determinant of T cell expansion and effector function. However, little is known about how tumor antigen affinity impacts T cell differentiation and dysfunction in progressing tumors. To investigate the functional and molecular programs determined by affinity, we generated an in vivo tumor model expressing altered peptide ligands (APL) derived from SV40 large T antigen epitope I (TAG) and recognized by TAG-specific transgenic CD8 T cells (TCRTAG) with varying functional avidity. While affinity did not impact T cell activation and differentiation in tumor draining lymph nodes, it drove distinct functional and molecular programs at the tumor site. Interestingly, key transcription factors and effector molecules were regulated by signal strength, preserving a cell-intrinsic functional program in T cells with low-affinity interactions. In contrast, certain hallmarks of T cell dysfunction, including the expression of inhibitory receptors (e.g. PD1 and LAG3), were affinity-independent, revealing that even very weak TCR ligations can induce a typical exhaustion phenotype. Ongoing studies will define the transcriptional and epigenetic programs underlying the distinct dysfunctional T cell states in tumors driven by TCR signal strength.

Catch and Release of Cytokines Mediated by Tumor Phosphatidylserine Converts Transient Exposure into Long-Lived Inflammation

Immune cells constantly survey the host for pathogens or tumors and secrete cytokines to alert surrounding cells of these threats. In vivo, activated immune cells secrete cytokines for several hours, yet an acute immune reaction occurs over days. Given these divergent timescales, we addressed how cytokine-responsive cells translate brief cytokine exposure into phenotypic changes that persist over long timescales. We studied melanoma cell responses to transient exposure to the cytokine interferon γ (IFNγ) by combining a systems-scale analysis of gene expression dynamics with computational modeling and experiments. We discovered that IFNγ is captured by phosphatidylserine (PS) on the surface of viable cells both in vitro and in vivo then slowly released to drive long-term transcription of cytokine-response genes. This mechanism introduces an additional function for PS in dynamically regulating inflammation across diverse cancer and primary cell types and has potential to usher in new immunotherapies targeting PS and inflammatory pathways.

Chromatin states define tumour-specific T cell dysfunction and reprogramming

Tumour-specific CD8 T cells in solid tumours are dysfunctional, allowing tumours to progress. The epigenetic regulation of T cell dysfunction and therapeutic reprogrammability (for example, to immune checkpoint blockade) is not well understood. Here we show that T cells in mouse tumours differentiate through two discrete chromatin states: a plastic dysfunctional state from which T cells can be rescued, and a fixed dysfunctional state in which the cells are resistant to reprogramming. We identified surface markers associated with each chromatin state that distinguished reprogrammable from non-reprogrammable PD1^hi dysfunctional T cells within heterogeneous T cell populations from tumours in mice; these surface markers were also expressed on human PD1^hi tumour-infiltrating CD8 T cells. Our study has important implications for cancer immunotherapy as we define key transcription factors and epigenetic programs underlying T cell dysfunction and surface markers that predict therapeutic reprogrammability.

Impact of antigen affinity on T cell dysfunction in solid tumors

Although tumor-specific T cells (TST) are found in human solid tumors, cancers progress, indicating that these T cells are dysfunctional. TSTs express high levels of inhibitory receptors and fail to execute effector functions; however, the regulatory mechanisms underlying TST dysfunction remain poorly defined. T cell mediated immune response is triggered by T cell receptor (TCR) binding to peptide-major histocompatibility (pMHC) complex on the surface of cells. The affinity of TCR:pMHC interaction is a critical determinant of T cell expansion and effector function in acute infections, where T cells with high affinity interactions generally show superior function. However, little is known about how TCR:pMHC affinity impacts T cells activation, induction of dysfunction and susceptibility to immunotherapy in progressing tumors. To elucidate this, we generated tumor cell lines expressing altered peptide ligands derived from SV40 large T antigen epitope I (Tag) and recognized by Tag-specific transgenic CD8 T cells (TCRTag) with varying functional avidity. We found that tumor-infiltrating TCRTag encountering low and high affinity tumor antigens were equally activated and expressed similar levels of inhibitory receptors, suggesting that even very weak TCR ligations can induce a typical “exhaustion” phenotype. Strikingly, while high affinity TCR:pMHC interactions led to complete loss of cytokine production, T cells with low affinity interactions remained functional, suggesting that TSTs with high affinity TCR:pMHC interactions enter a profound state of dysfunction. Future experiments will test the impact of tumor antigen affinity on the efficacy of therapeutic reprogramming, with important implications for immunotherapy.

ProteoModlR for functional proteomic analysis

Background

High-accuracy mass spectrometry enables near comprehensive quantification of the components of the cellular proteomes, increasingly including their chemically modified variants. Likewise, large-scale libraries of quantified synthetic peptides are becoming available, enabling absolute quantification of chemically modified proteoforms, and therefore systems-level analyses of changes of their absolute abundance and stoichiometry. Existing computational methods provide advanced tools for mass spectral analysis and statistical inference, but lack integrated functions for quantitative analysis of post-translationally modified proteins and their modification stoichiometry.

Results

Here, we develop ProteoModlR, a program for quantitative analysis of abundance and stoichiometry of post-translational chemical modifications across temporal and steady-state biological states. While ProteoModlR is intended for the analysis of experiments using isotopically labeled reference peptides for absolute quantitation, it also supports the analysis of labeled and label-free data, acquired in both data-dependent and data-independent modes for relative quantitation. Moreover, ProteoModlR enables functional analysis of sparsely sampled quantitative mass spectrometry experiments by inferring the missing values from the available measurements, without imputation. The implemented architecture includes parsing and normalization functions to control for common sources of technical variation. Finally, ProteoModlR’s modular design and interchangeable format are optimally suited for integration with existing computational proteomics tools, thereby facilitating comprehensive quantitative analysis of cellular signaling.

Conclusions

ProteoModlR and its documentation are available for download at http://github.com/kentsisresearchgroup/ProteoModlR as a stand-alone R package.

Electronic supplementary material

The online version of this article (doi:10.1186/s12859-017-1563-6) contains supplementary material, which is available to authorized users.

Abstract A093: Impact of antigen affinity on T cell dysfunction in solid tumors

Although tumor-specific CD8 T cells are found in human solid tumors, cancers progress, indicating that these T cells are dysfunctional. When naïve CD8 T cells encounter antigen in an inflammatory context (e.g. acute infection), a cell-intrinsic program is initiated that drives T cells to expand, produce effector cytokines, and differentiate into effector and memory T cells. In contrast, dysfunctional CD8 T cells in solid tumors express high levels of inhibitory receptors and fail to execute effector functions; however, the regulatory mechanisms underlying tumor-specific T cell dysfunction remain poorly defined. T cell-mediated immune responses are triggered by T cell receptor (TCR) binding to peptide-major histocompatibility complex (pMHC) on the surface of antigen presenting cells. The affinity of TCR:pMHC interaction is a critical determinant of CD8 T cell expansion and effector function in acute infections; while both low- and high-affinity antigens can activate naïve antigen-specific CD8 T cells, T cells with high-affinity TCR:pMHC interactions generally show superior effector function. However, little is known about how tumor antigen affinity impacts the activation of T cells, the induction of T cell dysfunction in progressing tumors, and T cell susceptibility to immunotherapeutic reprogramming. To investigate the role of TCR:pMHC affinity in T cell differentiation in progressing tumors, we generated tumor cell lines expressing altered peptide ligands (APL) derived from SV40 large T antigen epitope I (SV40-I). These APLs are recognized by SV40-I-specific transgenic CD8 T cells (TCRSV40-I) with varying functional avidity. We found that tumor-infiltrating TCRSV40-I encountering low- and high-affinity tumor antigens were equally activated and displayed similar expression levels of inhibitory receptors, such as PD1 and Lag3, suggesting that even very weak TCR ligations can induce a typical “exhaustion” phenotype. Strikingly, while high-affinity TCR:pMHC interactions led to complete loss of interferon gamma and tumor necrosis factor alpha production, T cells with low-affinity interactions remained functional and capable of producing high levels of these effector cytokines suggesting that contrary to our expectations, tumor-specific T cells with high-affinity TCR:pMHC interactions enter a profound state of dysfunction. Future experiments will test the impact of tumor antigen affinity on the efficacy of therapeutic reprogramming including checkpoint blockade, which will have important implications for immunotherapy.

Citation Format: Mojdeh Shakiba, Mary Philip, Andrea Schietinger. Impact of antigen affinity on T cell dysfunction in solid tumors [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 A093.

Stable J-aggregation enabled dual photoacoustic and fluorescence nanoparticles for intraoperative cancer imaging

J-aggregates display nanoscale optical properties which enable their use in fluorescence and photoacoustic imaging applications. However, control over their optical properties in an in vivo setting is hampered by the conformational lability of the J-aggregate structure in complex biological environments. J-aggregating nanoparticles (JNP) formed by self-assembly of bacteriopheophorbide-lipid (Bchl-lipid) in lipid nanovesicles represents a novel strategy to stabilize J-aggregates for in vivo bioimaging applications. We find that 15 mol% Bchl-lipid embedded within a saturated phospholipid bilayer vesicle was optimal in terms of maximizing Bchl-lipid dye loading, while maintaining a spherical nanoparticle morphology and retaining spectral properties characteristic of J-aggregates. The addition of cholesterol maintains the stability of the J-aggregate absorption band for up to 6 hours in the presence of 90% FBS. In a proof-of-concept experiment, we successfully applied JNPs as a fluorescence contrast agent for real-time intraoperative detection of metastatic lymph nodes in a rabbit head-and-neck cancer model. Lymph node metastasis delineation was further verified by visualizing the JNP within the excised lymph node using photoacoustic imaging. Using JNPs, we demonstrate the possibility of using J-aggregates as fluorescence and photoacoustic contrast agents and may potentially spur the development of other nanomaterials that can stably induce J-aggregation for in vivo cancer bioimaging applications.

In situ conversion of porphyrin microbubbles to nanoparticles for multimodality imaging

Converting nanoparticles or monomeric compounds into larger supramolecular structures by endogenous or external stimuli is increasingly popular because these materials are useful for imaging and treating diseases. However, conversion of microstructures to nanostructures is less common. Here, we show the conversion of microbubbles to nanoparticles using low-frequency ultrasound. The microbubble consists of a bacteriochlorophyll-lipid shell around a perfluoropropane gas. The encapsulated gas provides ultrasound imaging contrast and the porphyrins in the shell confer photoacoustic and fluorescent properties. On exposure to ultrasound, the microbubbles burst and form smaller nanoparticles that possess the same optical properties as the original microbubble. We show that this conversion is possible in tumour-bearing mice and could be validated using photoacoustic imaging. With this conversion, our microbubble can potentially be used to bypass the enhanced permeability and retention effect when delivering drugs to tumours.

Effect of surface modification by nitrogen ion implantation on the electrochemical and cellular behaviors of super-elastic NiTi shape memory alloy

The aim of this investigation was to enhance the biological behavior of NiTi shape memory alloy while preserving its super-elastic behavior in order to facilitate its compatibility for application in human body. The surfaces of NiTi samples were bombarded by three different nitrogen doses. Small-angle X-ray diffraction was employed for evaluating the generated phases on the bombarded surfaces. The electrochemical behaviors of the bare and surface-modified NiTi samples were studied in simulated body fluid (SBF) using electrochemical impedance and potentio-dynamic polarization tests. Ni ion release during a 2-month period of service in the SBF environment was evaluated using atomic absorption spectrometry. The cellular behavior of nitrogen-modified samples was studied using fibroblast cells. Furthermore, the effect of surface modification on super-elasticity was investigated by tensile test. The results showed the improvement of both corrosion and biological behaviors of the modified NiTi samples. However, no significant change in the super-elasticity was observed. Samples modified at 1.4E18 ion cm(-2) showed the highest corrosion resistance and the lowest Ni ion release.

Dynamic contrast-enhanced MRI for differentiation of major salivary glands neoplasms, a 3-T MRI study

OBJECTIVES

Pre-operative differentiation of salivary gland neoplasms is of great importance. This study was designed to evaluate the use of dynamic contrast-enhanced MRI (DCE-MRI) for differentiation between malignant, Warthin and benign non-Warthin (BNW) neoplasms of major salivary glands.

METHODS

46 major salivary gland tumours (SGTs) underwent pre-operative DCE-MRI. Post-surgical histopathological evaluation showed 30 BNW, 6 Warthin and 10 malignant tumours. Time-signal intensity curves (TICs) were categorized as (a) Tpeak >43 s and washout ratio at 180 s (WR180) <4.6%; (b) Tpeak <43 s and WR >22%; (c) Tpeak >43 s and WR180 = 4.6-22.0%

RESULTS

Accuracy of Tpeak was 98.9% for differentiation between BNW and Warthin tumours, 83.7% between BNW and malignant and 80% between malignant and Warthin tumours. All Warthin tumours showed Tpeak ≤43 s, while one BNW had Tpeak <43 s. A Tpeak <63.5 s differentiated 8/10 (80%) malignant tumours from BNW tumours, whereas 4/30 of BNW tumours had a Tpeak <63.5 s. Two malignant tumours had Tpeak <43 s. WR180 had an accuracy of 100% for differentiation between Warthin and BNW tumours, 87.3% between BNW and malignant, and 93.3% between Warthin and malignant tumours. 29 (96.7%) BNW tumours had a washout <4.60%, while 8 (80%) malignant tumours had a washout >4.60%. All Warthin tumours had a WR180 >22%, while two malignant tumours had a WR180 >22%. 29/30 of BNW tumours demonstrated TIC curve Type A and 1 tumour demonstrated Type C. 6/10 of malignant tumours had TIC Type C, 2 had TIC Type A and 2 Type B. All Warthin tumours were categorized as Type B.

CONCLUSIONS

This study showed that DCE-MRI could be helpful in pre-operative differentiation of SGTs; especially for discrimination between Warthin and BNW tumours.

Stimuli-responsive photoacoustic nanoswitch for in vivo sensing applications

Photoacoustic imaging provides high-resolution images at depths beyond the optical diffusion limit. To broaden its utility, there is need for molecular sensors capable of detecting environmental stimuli through alterations in photoacoustic signal. Photosynthetic organisms have evolved ingenious strategies to optimize light absorption through nanoscale ordered dye aggregation. Here, we use this concept to synthesize a stimuli-responsive nanoswitch with a large optical absorbance and sensing capabilities. Ordered dye aggregation between light-harvesting porphyrins was achieved through intercalation within thermoresponsive nanovesicles. This causes an absorbance red-shift of 74 nm and a 2.7-fold increase in absorptivity of the Qy-band, with concomitant changes in its photoacoustic spectrum. This spectral feature can be reversibly switched by exceeding a temperature threshold. Using this thermochromic property, we noninvasively determined a localized temperature change in vivo, relevant for monitoring thermal therapies of solid tumors. Similar strategies may be applied alongside photoacoustic imaging, to detect other stimuli such as pH and enzymatic activity.

Microfabricated photocrosslinkable polyelectrolyte-complex of chitosan and methacrylated gellan gum

Chitosan (CHT) based polyelectrolyte complexes (PECs) have been receiving great attention for tissue engineering approaches. These hydrogels are held together by ionic forces and can be disrupted by changes in physiological conditions. In this study, we present a new class of CHT-based PEC hydrogels amenable to stabilization by chemical crosslinking. The photocrosslinkable anionic methacrylated gellan gum (MeGG) was complexed with cationic CHT and exposed to light, forming a PEC hydrogel. The chemical characterization of the photocrosslinkable PEC hydrogel by Fourier transform infrared spectroscopy (FTIR) revealed absorption peaks specific to the raw polymers. A significantly higher swelling ratio was observed for the PEC hydrogel with higher CHT content. The molecular interactions between both polysaccharides were evaluated chemically and microscopically, indicating the diffusion of CHT to the interior of the hydrogel. We hypothesized that the addition of MeGG to CHT solution first leads to a membrane formation around MeGG. Then, migration of CHT inside the MeGG hydrogel occurs to balance the electrostatic charges. The photocrosslinkable feature of MeGG further allowed the formation of cell-laden microscale hydrogel units with different shapes and sizes. Overall, this system is potentially useful for a variety of applications including the replication of microscale features of tissues for modular tissue engineering.

Hematologic manifestations in a child with HIV; a Case Report

BACKGROUND

Immune deficiency in human might be primary or secondary and could be seen with a wide variety of manifestations. In the following, we presented a Child with various complains that diagnosed to have HIV infection.

CASE REPORT

A 2/5 y/o child was admitted to the hospital for FUO with prolonged cough, FTT, cervical lymphadenopathy, hepatosplenomegaly and bilateral optic neuritis. . He was hospitalized for fever, cytopenia and hepatosplenomegaly one year ago, and three months later in an outpatient visit, these signs improved, except thrombocytopenia. In evaluation, bicytopenia, elevated ESR, hyperlipidemia, hyperproteinemia, thrombosis of the transverse sinus of brain, antiphospholipid antibodies , decreased levels of protein S and factor V Leiden and increased level of anti thrombin III were detected. Consequently, the result of HIV antibody showed positive. In addition to warfarin and cotrimoxazole therapy, he was referred to special center for possible HARRT therapy.

CONCLUSION

In approach to patients with various clinical presentations such as cytopenia, recurrent or persistent lymphadenopathy, unexplained hyperproteinemia or hyperlipidemia, evaluation of HIV infection is highly recommended for consideration and further therapy.

1-hexyl n-cyanoacrylate compound (Neucrylate™ AN), a new treatment for berry aneurysm. III: Initial clinical results

INTRODUCTION

As part of an institutionally approved research protocol, patients with cerebral berry aneurysm were enrolled in a clinical trial designed to evaluate the safety of the new moldable liquid embolic agent Neucrylate AN.

METHODS

Twelve patients with aneurysms judged to be suboptimal for treatment by standard endovascular or surgical approaches were treated with Neucrylate AN. The agent was injected during temporary balloon occlusion at the neck of the aneurysm. The immediate angiographic percentage of aneurysm occlusion and periprocedural adverse events were assessed for each patient. Six-month follow-up angiographic studies were obtained for nine of the 12 patients.

RESULTS

Ten of the 12 aneurysms treated (83%) were large to giant (>1.0 cm in diameter), nine (75%) were wide-necked (dome/neck ratio <2.0) and three (25%) were dissecting aneurysms. There were four (33%) periprocedural neurological events. Immediate aneurysm occlusion of >90% was obtained in nine of the 12 cases (75%). There were five recurrences (55.5%) at 6 months.

CONCLUSION

This preliminary clinical series shows that it is feasible to achieve a high percentage of immediate aneurysm occlusion with limited patient morbidity and mortality in the setting of morphologically challenging aneurysms. These preliminary data support larger trials assessing the safety and efficacy of this agent.

Evaluation of Angiographic Findings in Spontaneous Aneurysmal Subarachnoid Hemorrhage Patients

This paper describes the angiographic findings of spontaneous aneurysmal subarachnoid hemorrhage (SAH) patients, including frequency, anatomic location and multiplicity of cerebral aneurysms. We retrospectively reviewed the records of 796 SAH patients at our university affiliated hospital. After confirming SAH by lumbar puncture or CT scan, all patients underwent digital subtraction angiography to find the definite anatomic location. The male to Female ratio in SAH patients was 9:10. The mean (SD) age of all patients with SAH was 47.9±14.7 years. The mean (SD) age of men with SAH was 46.6±15.6 years and women with SAH was 49.3±13.5 years (P=0.015). 357 (44.8%) patients had aneurysms. The mean (SD) age of aneurysmal patients was 49.8±14.3 years. The mean (SD) age of men with aneurysm was 47.8 ±15.9 years and women with aneurysm was 51.3±12.9 years (P ? 0.03). The male to female ratio in aneurysms was 0.72:1. The most common aneurysm location was in the anterior communicating artery (N=166, 39%). The second most common anatomic location was the middle cerebral artery bifurcation (66 left, 60 right). The total number of patients with single aneurysms was 303 (84.9%) while 54 (15.1%) patients had multiple aneurysms. Among these patients, 49 had two aneurysms, three had three aneurysms and two had four aneurysms. In all, 418 aneurysms were detected. Of 357 patients with aneurysms 150 (42%) had vasospasm during angiography. In conclusion, the most common aneurysm location was the anterior communicating artery and the rate of multiplicity was also higher in our patients.

Combination of bolus dose vitamin D with routine vaccination in infants: a randomised trial

INTRODUCTION

The present study was designed to compare two methods of vitamin D supplementation in infants: every two months as a routine vaccination versus a daily dose.

METHODS

A randomised clinical trial was performed on 120 healthy breastfed infants between January and September 2007 in Yazd, Iran. The infants were randomly divided into three groups with different doses of vitamin D3 supplementation: 200 IU daily, 400 IU daily and a bolus of 50,000 IU every two months. A blood sample was taken and evaluated for 25-hydroxy vitamin D and calcium levels when the infants were six months old. The data was reported as the mean and standard deviation.

RESULTS

No significant differences were observed between the serum level of 25-hydroxy vitamin D in the groups administered with 200 IU and 400 IU vitamin D daily. However, the serum level of 25-hydroxy vitamin D reached significance in the third group (p is less than 0.001). All the blood calcium measured was below 11 mg/dl in the bolus group. A few complications such as diarrhoea and agitation, all of which were self-limited, were seen in the bolus group. No other significant side effects were reported in the other groups.

CONCLUSION

This study demonstrates that a bolus of 50,000 IU of vitamin D every two months with a routine child vaccination program provides the ideal serum level of vitamin D. This method produces no serious side effects and offers a highly convenient way to supply vitamin D, especially among non-compliant parents.

Prognostic value of brain tissue pathological changes in patients with clinically isolated syndromes (CIS) suggestive of multiple sclerosis using magnetization transfer ratio (MTR)

The aim of this study is to investigate abnormalities in the brain tissue of patients with clinically isolated syndrome (CIS) suggestive of multiple sclerosis (MS). In this method, magnetization transfer ratio (MTR) parameter accompanied with segmentation regional measurements and histogram analysis were used to improve the evaluation of disease progression in CIS patients. Conventional MR imaging protocols such as T1-weighted, T2-weighted, T2-FLAIR as well as MT-2DSPGR were performed on four CIS patients and four normal subjects. White matter, gray matter and lesion masks were segmented from T2-weighted images and superimposed on MTR map using FSL software. Lesions were classified into isontense and severely hypointense according to their signal intensities relative to white matter on the T1-weighted images. MTR parameters of these two lesion types, normal appearing white matter (NAWM) and normal appearing gray matter (NAGM) were analyzed in comparison with those of normal controls. The MTR histograms of NAWM and NAGM were also generated for each segmented brain tissues. A significant reduction was found in mean white matter MTR and the histogram peak position between CIS patients and healthy subjects. The MTR histogram for NAWM showed also a total shift to the left. The MTR value for gray matter in CIS patients was similar to that of controls. Isointense lesions have significantly higher MTR values than severely hypointense lesions. Significant reduction in NAWM-MTR compared to normal subjects shows that pathological changes outside visible lesions on conventional MR images occur among patients with CIS at presentation. Quantitative MT imaging can help to evaluate the extent of global damage in the brain tissue.

Urinary tract infections in pregnant women with bacterial vaginosis

Urinary tract infections (UTIs) and bacterial vaginosis are common problems in pregnancy and are associated with serious obstetric complications. We evaluated the risk of UTIs in pregnant women with bacterial vaginosis. A total of 322 pregnant women who presented for a prenatal visit were evaluated for bacterial vaginosis and UTIs, between March 2003 and September 2004. Bacterial vaginosis was diagnosed based on Amsel's criteria. Women using antibiotic or other vaginal cream, with specific vaginitis or vaginal bleeding were excluded. Data were analysed using chi(2), Student t-test and multiple logistic regression. A total of 76 women had bacterial vaginosis and 246 women did not; and 18 women (23.6%) with bacterial vaginosis had UTIs, compared with 24 (9.8%) of those without. Bacterial vaginosis was associated with an increased risk of UTIs (odds ratio (OR) 3.05; 95% CI: 1.47-6.33). Pregnant women with bacterial vaginosis are at increased risk for UTIs.

Introducing a new scoring system based on HER2/neu, p53 oncogenes results and mammographic findings for prediction of tumor grade in breast cancer

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Background: During recent years, several oncogenes have been introduced in relation to breast cancer including her2 and P53. These are related with initiation, degree of progression, invasion and prognosis of breast cancer. In this research the rate of positivity of these oncogenes in 150 patients with invasive ductal carcinoma is introduced and the correlation of the results of a new scoring system comprised of mammograms, P53 and her2 with the tumor grade is assessed. Methods: 150 cases of invasive ductal carcinoma of a private clinic were chosen. The diagnosis of cancer and its grade was confirmed by pathology. All patients underwent mammography befor surgery and the results were classified according to BIRADS system to benign (groups of I and II in BIRADS): Score I, suspicious (group III in BIRADS): Score II and malignant (groups of IV and V in BIRADS): score III. P53 and her2 presence were assessed by immunohistochemical studies and the results were classified as negative (score I) and positive (score II). The final score of each patients was calculated by adding scores of all three studies (P53, her2, mammography) which ranged between 3 to 7. Results: The average age of the patients was 48.2 + 11.2 years; most of them were between 30–50 years old. Three had benign mammograms (2%), 81 had suspicious (54%) and 66 had malignant findings (44%). We showed positive P53in 59 (39%), positive her2 in 69 (46%) and high grade tumor in 77 (51%) patients. On scoring, 2 patients gained 3 (1.3%), 36 scored 4 (24%), 53 patients received 5 (35.3%), 37 reached 6 scores (24.7%) and 22 patients received 7 scores (14.7%). Placing scores 3 and 4 in one group and scores 5–7 in another, the sensitivity and negative predictive value of the system for high grade tumors reached 97.7% and 89.5% respectively. By placing scores 3–6 in one group and score 7 in another, the specificity and positive predictive value of the system reached to 100%. Conclusions: The results of mammography, P53 and her2 seems to have a good correlation with tumor grade, meaning when all three parameters are positive, the patients’ tumor is almost always high grade.

No significant financial relationships to disclose.

Biological control of Tiarosporella phaseolina the causal agent of charcoal rot of soybean

Charcoal rot caused by Tiarosporella phaseolina (Tassi) Van der Aa is an important disease of soybean in Gorgan province of Iran. Experiments were carried out with 95 bactenal isolates that were collected from the rhizosphere of soybean plant. Among these bacteria only 50 isolates showed antagonistic effect on Tiarosporella phaseolina using dual culture test. Six highly effective bacteria were selected for subsequent studies. Based on biochemical physiological and morphological tests, isolates Pf-12 and Pf-63 were identified as Pseudomonas fluorescens, isolates B-13, B-42,B-126 and B-84 as Bacillus subtilis. The isolates of P. fluorescens produced antibiotics as well as volatile metabolites that inhibited mycelial growth of fungus. Bacillus subtilis isolates inhibited the fungal growth through volatile and non-volatile metabolites production. Only P. fluorescens isolates produced hydrogen cyanide. In greenhouse studies, the isolates B-13 and B-126 reduced 59% and 66% the intensity of charcoal rot of soybean respectively. The combinations of isolates B-13 and B-126 were also effective on reducing the intensity of disease.