Current approach to hepatobiliary manifestations in inflammatory bowel disease

Inflammatory bowel disease (IBD), including the two main subtypes - Crohn's disease (CD) and ulcerative colitis (UC) - has a wide range of extra-intestinal manifestations (EIMs) that are major causes of morbidity and disability. The following EIMs can be classified as IBD-associated: mucocutaneous, ocular, pulmonary, renal, genitourinary, hematological, neurological, psychiatric, cardiac and hepatobiliary. The latter include primary sclerosing cholangitis (PSC), cholelithiasis, IgG4 associated cholangiopathy (IAC), autoimmune hepatitis (AIH), non-alcoholic fatty liver disease (NAFLD), hepatitis B and C, and drug-induced hepatotoxicity. The aim of this review is to examine our current knowledge of IBD - associated hepatobiliary EIMs and their treatment.

Adipocyte fatty acid binding protein (A-FABP) as a potential new therapeutic target for treatment of obesity - associated cancers

Fatty acid binding protein A (A-FABP) is one of FABPs isoforms found mainly in adipose tissue and macrophages. It works through many integrated pathways, regulating inflammation and lipid metabolism, promoting glucose production, impairing insulin function, and contributing to diseases such as atherosclerosis and diabetes. A-FABP is upregulated in the adipose tissue of obese patients and its increased release into the bloodstream is positively associated with body mass index. Consequently, A-FABP plays a key role in regulating metabolism in obese people. Recent studies in mouse models and in humans demonstrated the role of A-FABP in increasing risk of obesity-related cancers. Here we summarized the state of research on the link between obesity, cancer and A-FABP as a new potential therapeutic target for treatment of obesity - associated cancers.

AdipoRon, an Orally Active, Synthetic Agonist of AdipoR1 and AdipoR2 Receptors Has Gastroprotective Effect in Experimentally Induced Gastric Ulcers in Mice

Introduction: Adiponectin is a hormone secreted by adipocytes, which exhibits insulin-sensitizing and anti-inflammatory properties and acts through adiponectin receptors: AdipoR1 and AdipoR2. The aim of the study was to evaluate whether activation of adiponectin receptors AdipoR1 and AdipoR2 with an orally active agonist AdipoRon has gastroprotective effect and to investigate the possible underlying mechanism. Methods: We used two well-established mouse models of gastric ulcer (GU) induced by oral administration of EtOH (80% solution in water) or diclofenac (30 mg/kg, p.o.). Gastroprotective effect of AdipoRon (dose 5 and 50 mg/kg p.o.) was compared to omeprazole (20 mg/kg p.o.) or 5% DMSO solution (control). Clinical parameters of gastroprotection were assessed using macroscopic (gastric lesion area) and microscopic (evaluation of the gastric mucosa damage) scoring. To establish the molecular mechanism, we measured: myeloperoxidase (MPO), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities; glutathione (GSH) level; and IL-1β, adenosine monophosphate-activated protein kinase (AMPK), and phosphorylated AMPK expression in gastric tissue. Results: AdipoRon produced a gastroprotective effect in both GU mouse models as evidenced by significantly lower macroscopic and microscopic damage scores. AdipoRon exhibited anti-inflammatory effect by reduction in MPO activity and IL-1β expression in the gastric tissue. Moreover, AdipoRon induced antioxidative action, as demonstrated with higher GSH levels, and increased SOD and GPX activity. Conclusions: Activation of AdipoR1 and AdipoR2 using AdipoRon reduced gastric lesions and enhanced cell response to oxidative stress. Our data suggest that AdipoR1 and AdipoR2 activation may be an attractive therapeutic strategy to inhibit development of gastric ulcers.

[Strategies in Crohn's disease treatment - "step-up" vs. "top-down"]

Inflammatory bowel diseases (IBD) are chronic conditions that lead to serious complications and act to the detriment of quality of patients' lives. Etiology of IBD has not been precisely determined but it is assumed that IBD is caused by genetic, immune and environmental factors. The main target in current IBD treatment is the induction and maintenance of remission. The most common strategy in IBD therapy is called "step-up" that is based on gradual introduction of stronger drugs. However, the latest research shows that "top down" strategy is more promising and can change the natural course of the disease. The aim of this article is to discuss both strategies and compare their effectiveness.

Biologic Therapy in Crohn's Disease-What We Have Learnt So Far

Crohn's disease (CD) is an autoimmune disorder from the group of inflammatory bowel diseases. The etiology of CD is not clear; currently, the interaction between the genetic, immunological and environmental factors is assumed as the cause of the disease. Partial knowledge of those factors has led to the development of drugs, which control the clinical symptoms and improve the overall condition of the infected; the main objective of the modern therapeutic strategies is the induction and maintenance of remission. Among the wide range of available treatments, older generation molecules: mesalazine, corticosteroids and thiopurine derivatives as well as biological drugs and biosimilars can be distinguished. Moreover, some novel biologics and small molecule drugs have shown potential in CD clinical trials, providing safe and effective results. This article provides an overview of the achievements in the field of biologic therapy, its efficacy and safety with an indication of future directions in CD treatment.

Inflammation, Cancer and Immunity-Implication of TRPV1 Channel

Process of inflammation and complex interactions between immune and cancer cells within tumor microenvironment are known to drive and shape the outcome of the neoplastic disease. Recent studies increasingly show that ion channels can be used as potential targets to modulate immune response and to treat inflammatory disorders and cancer. The action of both innate and adaptive immune cells is tightly regulated by ionic signals provided by a network of distinct ion channels. TRPV1 channel, known as a capsaicin receptor, was recently documented to be expressed on the cells of the immune system but also aberrantly expressed in the several tumor types. It is activated by heat, protons, proinflammatory cytokines, and associated with pain and inflammation. TRPV1 channel is not only involved in calcium signaling fundamental for many cellular processes but also takes part in cell-environment crosstalk influencing cell behavior. Furthermore, in several studies, activation of TRPV1 by capsaicin was associated with anti-cancer effects. Therefore, TRPV1 provides a potential link between the process of inflammation, cancer and immunity, and offers new treatment possibilities. Nevertheless, in many cases, results regarding TRPV1 are contradictory and need further refinement. In this review we present the summary of the data related to the role of TRPV1 channel in the process of inflammation, cancer and immunity, limitations of the studies, and directions for future research.

Simultaneous miRNA and mRNA Transcriptome Profiling of Differentiating Equine Satellite Cells Treated with Gamma-Oryzanol and Exposed to Hydrogen Peroxide

Gamma-oryzanol (GO) is a popular supplement for performance horses, dogs, and humans. Previous studies indicated that GO supplementation decreases creatine kinase activity and lactate level after exercise and may affect oxidative stress in Thoroughbred horses. GO may change genes expression in equine satellite cells (ESC). The purpose of this study was to evaluate the effect of GO on miRNA, gene expression, oxidative stress, and cell damage and viability in differentiating ESC pretreated with hydrogen peroxide (H₂O₂). ESCs were obtained from a young horse’s skeletal muscle. ESCs were pre-incubated with GO (24 h) and then exposed to H₂O₂ for one hour. For the microRNA and gene expression assessment, the microarray technique was used. Identified miRNAs and genes were validated using real time-quantitative polymerase chain reaction. Several tests related to cell viability, cell damage, and oxidative stress were performed. The microarray analysis revealed differences in 17 miRNAs and 202 genes between GO-treated and control ESC. The tests related to apoptosis, cell viability, and oxidative stress showed that GO affects these processes to varying degrees. Our results suggest that GO can change miRNA and gene expression and may impact the processes involved in tissue repairing after an injury.

Adoptive cell transfer: new perspective treatment in veterinary oncology

Cancer immunotherapy is recently considered the most promising treatment for human patients with advanced tumors and could be effectively combined with conventional therapies such as chemotherapy or radiotherapy. Patients with hematological malignancies and melanoma have benefited greatly from immunotherapies such as, adoptive cell transfer therapy, experiencing durable remissions and prolonged survival. In the face of increasing enthusiasm for immunotherapy, particularly for the administration of tumor-specific T lymphocytes, the question arises whether this method could be employed to improve treatment outcomes for canine patients. It is warranted to determine whether veterinary clinical trials could support comparative oncology research and thus facilitate the development of new cell-based therapies for humans. Herein, we discuss adoptive transfer of T lymphocytes and lymphokine-activated cells for application in veterinary oncology, in the context of human medicine achievements. Furthermore, we discuss potential benefits of using domestic dog as a model for immunotherapy and its advantages for translational medicine. We also focus on an emerging genome-editing technology as a useful tool to improve a T cells’ phenotype.

Significance of Screening Tests and the Incidence of New Delhi Metallo-beta-lactamase-Producing Gram-negative Bacilli in the Surgery and Transplantation Wards of a Warsaw Medical Center During the Period From April 2014 to May 2017

BACKGROUND

The first New Delhi metallo-beta-lactamase (NDM)-producing bacteria were isolated in 2008 in the world, and in 2011 in Poland. Due to the high clonal diversity (17 types) of their blaNDM gene, encoded on (Tn125-like) mobile genetic elements, these strains usually exhibit resistance to nearly all available antibiotics, which is particularly dangerous for organ transplant recipients.

PURPOSE

To assess of the prevalence of Gram-negative NDM-positive bacilli in surgery/transplantation wards of a teaching hospital in Warsaw and to ascertain the significance of screening tests on the rates and nature of colonization.

MATERIALS AND METHODS

The evaluated strains were isolated from 30 patients (between April 2014 and May 2017). The species were identified with VITEK-MS, antibiotic susceptibility was determined with VITEK 2, disk-diffusion, and/or E-test methods, according to EUCAST guidelines. The presence of the blaNDM-1 gene was confirmed using the polymerase chain reaction technique.

RESULTS AND CONCLUSIONS

There were 77 blaNDM-1-positive Klebsiella pneumoniae strains isolated from 30 patients. Cultures from individual patients, mainly from rectal swabs (53.9%) and urine samples (39.8%), yielded 1-11 isolates. Fifteen patients were already colonized on admission, and the other 15 developed a symptomatic infection. In total, 24 (80%) patients were carriers, and their colonizations persisted for <1-20 months. Most isolates were susceptible only to colistin, gentamicin, amikacin, tigecycline, and/or sulfamethoxazole/trimethoprim. Gastrointestinal-tract-colonizing K pneumoniae are the main reservoir of the blaNDM-1 gene. Following the introduction of on-admission mandatory screening for carbapenem-resistant strains, the rates of NDM-producing K pneumoniae isolation increased (7.5-fold), while the rates of isolation from patients with symptomatic infections considerably decreased (2.8-fold).

In Vitro Priming of Adoptively Transferred T Cells with a RORγ Agonist Confers Durable Memory and Stemness In Vivo

Adoptive T-cell transfer therapy is an FDA- approved treatment for leukemia that relies on the ex vivo expansion and reinfusion of a patient's immune cells, which can be engineered with a chimeric antigen receptor (CAR) for more efficient tumor recognition. Type 17 T cells, controlled transcriptionally by RORγ, have been reported to mediate potent antitumor effects superior to those observed with conventionally expanded T cells. Here, we demonstrate that addition of a synthetic, small-molecule RORγ agonist during ex vivo expansion potentiates the antitumor activity of human Th17 and Tc17 cells redirected with a CAR. Likewise, ex vivo use of this agonist bolstered the antitumor properties of murine tumor-specific CD4⁺ and CD8⁺ T cells. Expansion in the presence of the RORγ agonist enhanced IL17A production without compromising IFNγ secretion in vitroIn vivo, cytokine neutralization studies revealed that IFNγ and IL17A were required to regress murine melanoma tumors. The enhanced antitumor effect of RORγ agonist treatment was associated with recovery of more donor T cells in the tumor and spleen; these cells produced elevated levels of cytokines months after infusion and expressed markers of long-lived stem and central memory cells such as Tcf7 and CD62L. Conversely, untreated cells mainly exhibited effector phenotypes in the tumor. Cured mice previously treated with agonist-primed T cells were protected from tumor rechallenge. Collectively, our work reveals that in vitro treatment with a RORγ agonist generates potent antitumor Type 17 effector cells that persist as long-lived memory cells in vivoSignificance: RORγ agonists can be used in vitro during T-cell expansion to enhance the efficacy of adoptive cell therapy (e.g., CAR-T) and to provide long-term protection against tumors.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/14/3888/F1.large.jpg Cancer Res; 78(14); 3888-98. ©2018 AACR.

Effect of Selective Antibiotic Pressure on the MLS-B Phenotype in Methicillin-Resistant Staphylococcus aureus Strains Originating From Patients From Transplantation Wards: 24 Years of Observations

INTRODUCTION

Staphylococcus aureus infection, and health care-associated-methicillin resistant S aureus (HA-MRSA) in particular, is a serious risk for patients treated with organ transplantation. The frequent combined resistance of these bacteria to macrolides, lincosamides, and streptogramin-B (MLS-B) limits the use of these drugs in therapy.

AIM

Evaluation of the mechanism of MLS-B resistance among HA-MRSA strains derived from patients treated in surgical-transplantation wards, over a 24-year period, and assessment of correlation of clindamycin use and resistance phenotype.

MATERIALS AND METHODS

One hundred and twelve HA-MRSA strains from patients in surgical-transplantation wards (clinical hospital, Warsaw), hospitalized in the period from 1991 to 2014. Methicillin-resistance was determined using phenotypic and genetic methods by detecting the mecA gene. Erythromycin/clindamycin resistance was determined by E-test, the iMLS-B (inductive) and cMLS-B (constitutive) phenotypes by the D-test method. The number of defined daily doses (DDD), statistically per 1000 person-days, was calculated in accordance with the WHO guidelines.

RESULTS

Resistance to erythromycin/clindamycin in MRSA strains increased from 1991 to 2004-2007 from 64.7/11.8% to 100/76.9%, respectively. The frequency of the cMLS-B phenotype in the years 1991/2010-2011/2012 was 5.9%/76.9%/69.7%, respectively, and correlated with the increased use of clindamycin in the examined wards. In 2012, the percentage of MLS-B-sensitive isolates increased from 3.9 to 21.7%, while constitutive resistance decreased to 69.7%, which correlated with a decrease in the use of clindamycin.

CONCLUSIONS

The proportion of cMLS-B to iMLS-B phenotypes in HA-MRSA is related to the amount of clindamycin used in hospital wards. Limiting the selection pressure of antibiotics can lead to complete loss of resistance or return to the inductive mechanism of its regulation.

Effect of β-hydroxy-β-methylbutyrate on miRNA expression in differentiating equine satellite cells exposed to hydrogen peroxide

Background

Skeletal muscle injury activates satellite cells to initiate processes of proliferation, differentiation, and hypertrophy in order to regenerate muscle fibers. The number of microRNAs and their target genes are engaged in satellite cell activation. β-Hydroxy-β-methylbutyrate (HMB) is known to prevent exercise-induced muscle damage. The purpose of this study was to evaluate the effect of HMB on miRNA and relevant target gene expression in differentiating equine satellite cells exposed to H₂O₂. We hypothesized that HMB may regulate satellite cell activity, proliferation, and differentiation, hence attenuate the pathological processes induced during an in vitro model of H₂O₂-related injury by changing the expression of miRNAs.

Methods

Equine satellite cells (ESC) were isolated from the samples of skeletal muscle collected from young horses. ESC were treated with HMB (24 h) and then exposed to H₂O₂ (1 h). For the microRNA and gene expression assessment microarrays, technique was used. Identified miRNAs and genes were validated using real-time qPCR. Cell viability, oxidative stress, and cell damage were measured using colorimetric method and flow cytometry.

Results

Analysis of miRNA and gene profile in differentiating ESC pre-incubated with HMB and then exposed to H₂O₂ revealed difference in the expression of 27 miRNAs and 4740 genes, of which 344 were potential target genes for identified miRNAs. Special attention was focused on differentially expressed miRNAs and their target genes involved in processes related to skeletal muscle injury. Western blot analysis showed protein protection in HMB-pre-treated group compared to control. The viability test confirmed that HMB enhanced cell survival after the hydrogen peroxide exposition.

Conclusions

Our results suggest that ESC pre-incubated with HMB and exposed to H₂O₂ could affect expression on miRNA levels responsible for skeletal muscle development, cell proliferation and differentiation, and activation of tissue repair after injury. Enrichment analyses for targeted genes revealed that a large group of genes was associated with the regulation of signaling pathways crucial for muscle tissue development, protein metabolism, muscle injury, and regeneration, as well as with oxidative stress response.

PARP1 inhibitor olaparib (Lynparza) exerts synthetic lethal effect against ligase 4-deficient melanomas

Cancer including melanoma may be ''addicted" to double strand break (DSB) repair and targeting this process could sensitize them to the lethal effect of DNA damage. PARP1 exerts an important impact on DSB repair as it binds to both single- and double- strand breaks. PARP1 inhibitors might be highly effective drugs triggering synthetic lethality in patients whose tumors have germline or somatic defects in DNA repair genes. We hypothesized that PARP1-dependent synthetic lethality could be induced in melanoma cells displaying downregulation of DSB repair genes. We observed that PARP1 inhibitor olaparib sensitized melanomas with reduced expression of DNA ligase 4 (LIG4) to an alkylatimg agent dacarbazine (DTIC) treatment in vitro, while normal melanocytes remained intact. PARP1 inhibition caused accumulation of DSBs, which was associated with apoptosis in LIG4 deficient melanoma cells. Our hypothesis that olaparib is synthetic lethal with LIG4 deficiency in melanoma cells was supported by selective anti-tumor effects of olaparib used either alone or in combination with dacarbazine (DTIC) in LIG4 deficient, but not LIG4 proficient cells. In addition, olaparib combined with DTIC inhibited the growth of LIG4 deficient human melanoma xenografts. This work for the first time demonstrates the effectiveness of a combination of PARP1 inhibitor olaparib and alkylating agent DTIC for treating LIG4 deficient melanomas. In addition, analysis of the TCGA and transcriptome microarray databases revealed numerous individual melanoma samples potentially displaying specific defects in DSB repair pathways, which may predispose them to synthetic lethality triggered by PARP1 inhibitor combined with a cytotoxic drug.

Human CD26high T cells elicit tumor immunity against multiple malignancies via enhanced migration and persistence

CD8⁺ T lymphocytes mediate potent immune responses against tumor, but the role of human CD4⁺ T cell subsets in cancer immunotherapy remains ill-defined. Herein, we exhibit that CD26 identifies three T helper subsets with distinct immunological properties in both healthy individuals and cancer patients. Although CD26^neg T cells possess a regulatory phenotype, CD26^int T cells are mainly naive and CD26^high T cells appear terminally differentiated and exhausted. Paradoxically, CD26^high T cells persist in and regress multiple solid tumors following adoptive cell transfer. Further analysis revealed that CD26^high cells have a rich chemokine receptor profile (including CCR2 and CCR5), profound cytotoxicity (Granzyme B and CD107A), resistance to apoptosis (c-KIT and Bcl2), and enhanced stemness (β-catenin and Lef1). These properties license CD26^high T cells with a natural capacity to traffic to, regress and survive in solid tumors. Collectively, these findings identify CD4⁺ T cell subsets with properties critical for improving cancer immunotherapy.

The role of human CD4⁺ T cell subsets in cancer immunotherapy is still unclear. Here, the authors show that CD26 identifies three CD4⁺ T cell subsets with distinct immunological properties in both healthy individuals and cancer patients.

PI3Kδ Inhibition Enhances the Antitumor Fitness of Adoptively Transferred CD8+ T Cells

Phosphatidylinositol-3-kinase p110δ (PI3Kδ) inhibition by Idelalisib (CAL-101) in hematological malignancies directly induces apoptosis in cancer cells and disrupts immunological tolerance by depleting regulatory T cells. Yet, little is known about the direct impact of PI3Kδ blockade on effector T cells from CAL-101 therapy. Herein, we demonstrate a direct effect of p110δ inactivation via CAL-101 on murine and human CD8⁺ T cells that promotes a strong undifferentiated phenotype (elevated CD62L/CCR7, CD127, and Tcf7). These CAL-101 T cells also persisted longer after transfer into tumor bearing mice in both the murine syngeneic and human xenograft mouse models. The less differentiated phenotype and improved engraftment of CAL-101 T cells resulted in stronger antitumor immunity compared to traditionally expanded CD8⁺ T cells in both tumor models. Thus, this report describes a novel direct enhancement of CD8⁺ T cells by a p110δ inhibitor that leads to markedly improved tumor regression. This finding has significant implications to improve outcomes from next generation cancer immunotherapies.

The Basics of Artificial Antigen Presenting Cells in T Cell-Based Cancer Immunotherapies

Adoptive T cell transfer (ACT) can mediate objective responses in patients with advanced malignancies. There have been major advances in this field, including the optimization of the ex vivo generation of tumor-reactive lymphocytes to ample numbers for effective ACT therapy via the use of natural and artificial antigen presenting cells (APCs). Herein we review the basic properties of APCs and how they have been manufactured through the years to augment vaccine and T cell-based cancer therapies. We then discuss how these novel APCs impact the function and memory properties of T cells. Finally, we propose new ways to synthesize aAPCs to augment the therapeutic effectiveness of antitumor T cells for ACT therapy.

The Influence of Hepatitis C Virus Therapy on the DNA Base Excision Repair System of Peripheral Blood Mononuclear Cells

Hepatitis C virus (HCV) can infect extrahepatic tissues, including lymphocytes, creating reservoir of the virus. Moreover, HCV proteins can interact with DNA damage response proteins of infected cells. In this article we investigated the influence of the virus infection and a new ombitasvir/paritaprevir/ritonavir ± dasabuvir ± ribavirin (OBV/PTV/r ± DSV ± RBV) anti-HCV therapy on the PBMCs (peripheral blood mononuclear cells, mainly lymphocytes) DNA base excision repair (BER) system. BER protein activity was analyzed in the nuclear and mitochondrial extracts (NE and ME) of PBMC isolated from patients before and after therapy, and from subjects without HCV, using modeled double-strand DNA, with 2'-deoxyuridine substitution as the DNA damage. The NE and ME obtained from patients before therapy demonstrated lower efficacy of 2'-deoxyuridine removal and DNA repair polymerization than those of the control group or patients after therapy. Moreover, the extracts from the patients after therapy had similar activity to those from the control group. However, the efficacy of apurinic/apyrimidinic site excision in NE did not differ between the studied groups. We postulate that infection of lymphocytes by the HCV can lead to a decrease in the activity of BER enzymes. However, the use of novel therapy results in the improvement of glycosylase activity as well as the regeneration of endonuclease and other crucial repair enzymes.

β-catenin and PI3Kδ inhibition expands precursor Th17 cells with heightened stemness and antitumor activity

ICOS costimulation generates Th17 cells with durable memory responses to tumor. Herein, we found that ICOS induces PI3K/p110δ/Akt and Wnt/β-catenin pathways in Th17 cells. Coinhibiting PI3Kδ and β-catenin altered the biological fate of Th17 cells. Th17 cells inhibited of both pathways expressed less RORγt, which, in turn, reduced their ability to secrete IL-17. Unexpectedly, these cells were more effective (than uninhibited cells) at regressing tumor when infused into mice, leading to long-term curative responses. PI3Kδ inhibition expanded precursor Th17 cells with a central memory phenotype that expressed nominal regulatory properties (low FoxP3), while β-catenin inhibition enhanced Th17 multifunctionality in vivo. Remarkably, upon TCR restimulation, RORγt and IL-17 rebounded in Th17 cells treated with PI3Kδ and β-catenin inhibitors. Moreover, these cells regained β-catenin, Tcf7, and Akt expression, licensing them to secrete heightened IL-2, persist, and eradicate solid tumors without help from endogenous NK and CD8 T cells. This finding shines a light on ways to repurpose FDA-approved drugs to augment T cell-based cancer immunotherapies.

Comparison of Staphylococcal Flora in Denture Plaque and the Surface of the Pharyngeal Mucous Membrane in Kidney Transplant Recipients

BACKGROUND

Biofilm occurring on removable prostheses is a reservoir of bacterial flora, consisting of both physiological and pathogenic multidrug-resistant microorganisms. Patients undergoing dialysis and organ transplantation are particularly prone to bacterial infections, which can have its source in denture plaque. This study was a comparison of the composition of staphylococcal flora within the surface of the pharyngeal mucous membrane as well as denture plaque in kidney transplant recipients.

METHODS

The study included 44 subjects with removable prostheses who reported for a kidney transplant procedure. Swab samples were collected from prostheses and the pharyngeal wall. Isolated strains were identified and investigated for drug resistance.

RESULTS

A total of 72 strains of Staphylococcus were isolated from the denture plaque and 53 from the pharynx. In the pharynx, the following species prevailed: Staphylococcus epidermidis, Staphylococcus warneri, and Staphylococcus aureus. The following species prevailed in denture plaque: S epidermidis, S aureus, and Staphylococcus haemolyticus. Among the pharyngeal strains, antibiotic resistance most commonly referred to natural penicillin (77%), constitutive macrolide-lincosamide-streptogramin B resistance (28%), and tetracycline (26.4%). In case of denture plaque, the highest percentage of strains demonstrated resistance to natural penicillin (60%), fosfomycin (32%), and cefoxitin (25%). In 10 subjects (48%), Staphylococcus-induced infections occurred in the first year after transplantation, 5 of which had the same bacterial strain as cultured previously from dentures.

CONCLUSIONS

The denture biofilm and surface of the pharynx differ in terms of bacterial composition and bacterial drug resistance profiles. Denture plaque constitutes a considerable reservoir of staphylococcal flora, which can be a potential source of infection in organ transplant recipients.

Th17 cells are refractory to senescence and retain robust antitumor activity after long-term ex vivo expansion

Adoptive immunotherapy for solid tumors relies on infusing large numbers of T cells to mediate successful antitumor responses in patients. While long-term rapid-expansion protocols (REPs) produce sufficient numbers of CD8⁺ T cells for treatment, they also cause decline in the cell's therapeutic fitness. In contrast, we discovered that IL-17-producing CD4⁺ T cells (Th17 cells) do not require REPs to expand 5,000-fold over 3 weeks. Also, unlike Th1 cells, Th17 cells do not exhibit hallmarks of senescence or apoptosis, retaining robust antitumor efficacy in vivo. Three-week-expanded Th17 cells eliminated melanoma as effectively as Th17 cells expanded for 1 week when infused in equal numbers into mice. However, treating mice with large recalcitrant tumors required the infusion of all cells generated after 2 or 3 weeks of expansion, while the cell yield obtained after 1-week expansion was insufficient. Long-term-expanded Th17 cells also protected mice from tumor rechallenge including lung metastasis. Importantly, 2-week-expanded human chimeric antigen receptor-positive (CAR⁺) Th17 cells also retained their ability to regress human mesothelioma, while CAR⁺ Th1 cells did not. Our results indicate that tumor-reactive Th17 cells are an effective cell therapy for cancer, remaining uncompromised when expanded for a long duration owing to their resistance to senescence.

Synthetic RORγ agonists regulate multiple pathways to enhance antitumor immunity

RORγt is the key transcription factor controlling the development and function of CD4⁺ Th17 and CD8⁺ Tc17 cells. Across a range of human tumors, about 15% of the CD4⁺ T cell fraction in tumor-infiltrating lymphocytes are RORγ+ cells. To evaluate the role of RORγ in antitumor immunity, we have identified synthetic, small molecule agonists that selectively activate RORγ to a greater extent than the endogenous agonist desmosterol. These RORγ agonists enhance effector function of Type 17 cells by increasing the production of cytokines/chemokines such as IL-17A and GM-CSF, augmenting expression of co-stimulatory receptors like CD137, CD226, and improving survival and cytotoxic activity. RORγ agonists also attenuate immunosuppressive mechanisms by curtailing Treg formation, diminishing CD39 and CD73 expression, and decreasing levels of co-inhibitory receptors including PD-1 and TIGIT on tumor-reactive lymphocytes. The effects of RORγ agonists were not observed in RORγ−/− T cells, underscoring the selective on-target activity of the compounds. In vitro treatment of tumor-specific T cells with RORγ agonists, followed by adoptive transfer to tumor-bearing mice is highly effective at controlling tumor growth while improving T cell survival and maintaining enhanced IL-17A and reduced PD-1 in vivo. The in vitro effects of RORγ agonists translate into single agent, immune system-dependent, antitumor efficacy when compounds are administered orally in syngeneic tumor models. RORγ agonists integrate multiple antitumor mechanisms into a single therapeutic that both increases immune activation and decreases immune suppression resulting in robust inhibition of tumor growth. Thus, RORγ agonists represent a novel immunotherapy approach for cancer.

Tumour-associated macrophages influence canine mammary cancer stem-like cells enhancing their pro-angiogenic properties

Cancer stem-like cells as cells with ability to self-renewal and potential to differentiate into various types of cells are known to be responsible for tumour initiation, recurrence and drug resistance. Hence a comprehensive research is concentrated on discovering cancer stem-like cells biology and interdependence between them and other cells. The aim of our study was to evaluate the impact of macrophages on cancer stem-like cells in canine mammary carcinomas. As recent studies indicated presence of macrophages in cancer environment stimulates cancer cells into more motile and invasive cells by acquisition of macrophage phenotypes. From two canine mammary tumour cell lines, CMT-U27 and P114 cancer stem-like cells were stained with Sca1, CD44 and EpCAM monoclonal antibodies and isolated. Those cells were next co-cultured with macrophages for 5 days and used for further experiments. Canine Gene Expression Microarray revealed 29 different expressed transcripts in cancer stem-like cells co-cultured with macrophages compared to those in mono-culture. Up-regulation of C-C motif chemokine 2 was considered as the most interesting for further investigation. Additionally, those cells showed overexpression of genes involved in non-canonical Wnt pathway. The results of 3D tubule formation in endothelial cells induced by cancer stem-like cells co-cultured with macrophages compared to cancer stem-like cells from mono-cultures and with addition of Recombinant Canine CCL2/MCP-1 revealed the same stimulating effect. Based on those results we can conclude that macrophages have an impact on cancer stem-like cells increasing secretion of pro-angiogenic factors.

Th17 cells retain antitumor efficacy after long-term ex vivo expansion

Immunotherapies have produced impressive responses in melanoma patients by re-training their immune system to fight their cancer. One of the most successful of these methods is adoptive T cell therapy (ACT), which enriches, expands, and educates a patient’s tumor-reactive T cells before returning them to the patient. This therapy depends on infusing large numbers of cells (upwards of 1010 cells/patient) to mediate tumor regression, while also requiring cells of durable quality capable of sustaining long-term remission. Unfortunately, CD8+ T cells which are most often used, lose their antitumor efficacy as they are expanded ex vivo to large numbers. To circumvent this dilemma, we propose the use of IL-17 producing CD4+ T cells (Th17 cells), for ACT. We found that similar to CD8+ T cells, treatment with Th17 cells was more effective with higher numbers. These numbers can be achieved as Th17 cells expanded up to 10,000 fold after three weeks of ex vivo culture. At the end of culture, Th17 cells were as effective at eradicating melanomas as Th17 cells cultured for shorter duration. Between early and late culture time points, Th17 cells retained an effector memory phenotype (CD44+CD62L−) without acquiring markers of full effector and exhausted status, converted to a Th1-like functional profile (from mainly secreting IL17 to co-secreting IFNγ and IL17), and maintained the ability to engraft and persist in the host. We also demonstrate the power of combining the high yield and durable potency of Th17 cells by using their total yield at late culture to control clinically significant end-stage disease. These results support the advancement of Th17 cells to clinical trials to increase the number, quality, and duration of patient responses to treatment.

The quantity of CD26 on helper T cells correlates with the efficacy of adoptive cancer immunotherapy (TUM2P.1008)

Although Th17 cells cause striking tumor eradication upon transfer into mice bearing established melanoma, their translation into the clinic is barred by a lack of FDA-approved cytokines. Consequently, we sought to determine if IL-17-producing CD4+ cells could be enriched from peripheral blood. We found that functional Th17 cells could be isolated from blood, without the need for polarization, by using the surface marker CD26. Excitingly, very few CD26-rich cells, termed CD26high T cells, displayed striking antitumor activity and survival upon transfer into melanoma-bearing mice compared to CD26negative or bulk CD4+ T cells. Of translational significance, we found that human CD26high cells had heightened cytotoxicity and caused greater cancer cell death in vitro. Interestingly, human CD26high T cells have enhanced expression of cytokines (IL-17, IFN-γ, IL-2, TNFα), transcription factors (RORγ, Tbet), integrins (LFA-1, VLA-1) and chemokines (RANTES). Given the unique phenotype of CD26high T cells compared to cells with decreased CD26 expression, the question of this marker's importance is raised. Our preliminary studies reveal that the enzymatic activity of CD26 may be important for the enhanced function, cytotoxicity and migration of these cells and could possibly be targeted to enhance future therapies. Not only do CD26high T cells give hope for Th17 clinical translation, but also provide a potential mechanism by which to improve the T cells used for cancer immunotherapies.

Novel RORgamma agonists enhance anti-tumor activity of adoptive T cell therapy (TUM2P.1010)

Adoptive cell transfer (ACT) therapy using tumor infiltrating lymphocytes (TILs) or T cells modified to express chimeric antigen receptors is a promising anti-cancer approach. Evidence suggests that Th17 or Tc17 cells display superior anti-tumor activity over unpolarized T cells commonly used in ACT clinical trials. As an approach to improve the potency and persistence of ACT, synthetic RORɣ agonists were designed to bolster the generation of type 17 cells. In vitro stimulation in the presence of RORɣ agonists modulates expression of costimulatory and coinhibitory molecules and increases IL-17A, IL-22 and GM-CSF production while maintaining IFNɣ production. Additional investigation revealed that treating tumor-specific Th0, Th17, Tc0 or Tc17 T cells with a RORɣt agonist in vitro significantly enhanced their ability to regress large and established EG.7 lymphoma and B16F10 melanoma tumors in vivo. Animals receiving RORɣ agonist-treated T cells had increased frequency of transferred cells, elevated IL-17A levels and decreased PD-1 expression in tumors and spleen compared to control animals. Previous studies have also shown that systemic delivery of an RORɣ agonist can also enhance anti-tumor immune response in syngeneic pre-clinical tumor models. By enhancing cytokine/chemokine production, promoting survival as well as decreasing PD-1 expression, RORɣ agonist molecules provide an effective means to enhance the potency of adoptively transferred T cell products.

Analysis of microRNA expression in canine mammary cancer stem-like cells indicates epigenetic regulation of transforming growth factor-beta signaling

Cancer stem cells (CSCs) display both unique self-renewal ability as well as the ability to differentiate into many kinds of cancer cells. They are supposed to be responsible for cancer initiation, recurrence and drug resistance. Despite the fact that a variety of methods are currently employed in order to target CSCs, little is known about the regulation of their phenotype and biology by miRNAs. The aim of our study was to assess miRNA expression in canine mammary cancer stem-like cells (expressing stem cell antigen 1, Sca-1; CD44 and EpCAM) sorted from canine mammary tumour cell lines (CMT-U27, CMT-309 and P114). In order to prove their stem-like phenotype, we conducted a colony formation assay that confirmed their ability to form colonies from a single cell. Profiles of miRNA expression were investigated using Agilent custom-designed microarrays. The results were further validated by real-time rt-PCR analysis of expression of randomly selected miRNAs. Target genes were indicated and analysed using Kioto Encyclopedia of Genes and Genomes (KEGG) and BioCarta databases. The results revealed 24 down-regulated and nine up-regulated miRNAs in cancer stem-like cells compared to differentiated tumour cells. According to KEGG and BioCarta databases, target genes (n=240) of significantly down-regulated miRNAs were involved in transforming growth factor-beta signaling, mitogen-activated protein kinases (MAPK) signaling pathway, anaplastic lymphoma receptor tyrosine kinase (ALK) and peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PGC1A) pathways. The analysis of single-gene overlapping with different pathways showed that the most important genes were: TGFBR1, TGFBR2, SOS1, CHUK, PDGFRA, SMAD2, MEF2A, MEF2C and MEF2D. All of them are involved in tumor necrosis factor-beta signaling and may indicate its important role in cancer stem cell biology. Increased expression of TGFBR2, SMAD2, MEF2A and MEF2D in canine mammary cancer stem-like cells was further confirmed by real-time-qPCR. The results of our study point at epigenetic differences between cancer stem-like cells and differentiated tumour cells, which may be important not only for veterinary medicine but also for comparative oncology.

Natural compounds' activity against cancer stem-like or fast-cycling melanoma cells

Background

Accumulating evidence supports the concept that melanoma is highly heterogeneous and sustained by a small subpopulation of melanoma stem-like cells. Those cells are considered as responsible for tumor resistance to therapies. Moreover, melanoma cells are characterized by their high phenotypic plasticity. Consequently, both melanoma stem-like cells and their more differentiated progeny must be eradicated to achieve durable cure. By reevaluating compounds in heterogeneous melanoma populations, it might be possible to select compounds with activity not only against fast-cycling cells but also against cancer stem-like cells. Natural compounds were the focus of the present study.

Methods

We analyzed 120 compounds from The Natural Products Set II to identify compounds active against melanoma populations grown in an anchorage-independent manner and enriched with cells exerting self-renewing capacity. Cell viability, cell cycle arrest, apoptosis, gene expression, clonogenic survival and label-retention were analyzed.

Findings

Several compounds efficiently eradicated cells with clonogenic capacity and nanaomycin A, streptonigrin and toyocamycin were effective at 0.1 µM. Other anti-clonogenic but not highly cytotoxic compounds such as bryostatin 1, siomycin A, illudin M, michellamine B and pentoxifylline markedly reduced the frequency of ABCB5 (ATP-binding cassette, sub-family B, member 5)-positive cells. On the contrary, treatment with maytansine and colchicine selected for cells expressing this transporter. Maytansine, streptonigrin, toyocamycin and colchicine, even if highly cytotoxic, left a small subpopulation of slow-dividing cells unaffected. Compounds selected in the present study differentially altered the expression of melanocyte/melanoma specific microphthalmia-associated transcription factor (MITF) and proto-oncogene c-MYC.

Conclusion

Selected anti-clonogenic compounds might be further investigated as potential adjuvants targeting melanoma stem-like cells in the combined anti-melanoma therapy, whereas selected cytotoxic but not anti-clonogenic compounds, which increased the frequency of ABCB5-positive cells and remained slow-cycling cells unaffected, might be considered as a tool to enrich cultures with cells exhibiting melanoma stem cell characteristics.

Macrophages mediate a switch between canonical and non-canonical Wnt pathways in canine mammary tumors

Objective

According to the current hypothesis, tumor-associated macrophages (TAMs) are “corrupted” by cancer cells and subsequently facilitate, rather than inhibit, tumor metastasis. Because the molecular mechanisms of cancer cell–TAM interactions are complicated and controversial we aimed to better define this phenomenon.

Methods and Results

Using microRNA microarrays, Real-time qPCR and Western blot we showed that co-culture of canine mammary tumor cells with TAMs or treatment with macrophage-conditioned medium inhibited the canonical Wnt pathway and activated the non-canonical Wnt pathway in tumor cells. We also showed that co-culture of TAMs with tumor cells increased expression of canonical Wnt inhibitors in TAMs. Subsequently, we demonstrated macrophage-induced invasive growth patterns and epithelial–mesenchymal transition of tumor cells. Validation of these results in canine mammary carcinoma tissues (n = 50) and xenograft tumors indicated the activation of non-canonical and canonical Wnt pathways in metastatic tumors and non-metastatic malignancies, respectively. Activation of non-canonical Wnt pathway correlated with number of TAMs.

Conclusions

We demonstrated that TAMs mediate a “switch” between canonical and non-canonical Wnt signaling pathways in canine mammary tumors, leading to increased tumor invasion and metastasis.

Interestingly, similar changes in neoplastic cells were observed in the presence of macrophage-conditioned medium or live macrophages. These observations indicate that rather than being “corrupted” by cancer cells, TAMs constitutively secrete canonical Wnt inhibitors that decrease tumor proliferation and development, but as a side effect, they induce the non-canonical Wnt pathway, which leads to tumor metastasis.

These data challenge the conventional understanding of TAM–cancer cell interactions.

Five markers useful for the distinction of canine mammary malignancy

Background

Spontaneous canine mammary tumors constitute a serious clinical problem. There are significant differences in survival between cases with different tumor grades. Unfortunately, the distinction between various grades is not clear. A major problem in evaluating canine mammary cancer is identifying those, that are “truly” malignant. That is why the aim of our study was to find the new markers of canine malignancy, which could help to diagnose the most malignant tumors.

Results

Analysis of gene expression profiles of canine mammary carcinoma of various grade of malignancy followed by the boosted tree analysis distinguished a `gene set`. The expression of this gene set (sehrl, zfp37, mipep, relaxin, and magi3) differs significantly in the most malignant tumors at mRNA level as well as at protein level. Despite this `gene set` is very interesting as an additional tool to estimate canine mammary malignancy, it should be validated using higher number of samples.

Conclusions

The proposed gene set can constitute a `malignancy marker` that could help to distinguish the most malignant canine mammary carcinomas. These genes are also interesting as targets for further investigations and therapy. So far, only two of them were linked with the cancer development.

Expression and role of PGP, BCRP, MRP1 and MRP3 in multidrug resistance of canine mammary cancer cells

Background

In both women and female dogs, the most prevalent type of malignant neoplasm is the spontaneous mammary tumor. In dogs, half of these are malignant. The treatment of choice for the canine patients is surgical mastectomy. Unfortunately, it often fails in high-risk, locally invasive mammary tumors as of during the time of the surgery the micro-metastases are present. Moreover, there are neither large studies conducting to prove of the benefit from the chemotherapy in dogs nor established chemotherapy treatment protocols available. Additionally, the effectiveness of each individual chemotherapeutic agent and drug resistance of canine mammary cancer have not yet been characterized. That has become the aim of our study, to assess the expression of PGP, BCRP, MRP1 and MRP3 in canine mammary cancer cell lines and to investigate their role in cancer resistance to vinblastine, cisplatin and cyclophosphamide with using RNAi approach.

Results

The results suggested that in canine mammary cancer, the vinblastine efflux was mediated by PGP and MRP1 proteins, cisplatin efflux was mediated by all four examined efflux pumps (PGP, BCRP, MRP1 and MRP3), whereas cyclophosphamide resistance was related to BCRP activity. RNAi silencing of these efflux pumps significantly decreased IC50 doses of the examined drugs in canine mammary carcinoma cells.

Conclusions

Our results have indicated the treatment of cells involving use of the siRNA targeting efflux pumps could be a beneficial approach in the future.

Expression of inflammation-mediated cluster of genes as a new marker of canine mammary malignancy

Because canine mammary tumours constitute a serious clinical problem and there are no good prognostic markers (only histopathological variables are used), the aim of the presented study was to find new malignancy markers as well as to identify intracellular pathways and biological processes characteristic for canine mammary malignancy. We compared gene expression of the most malignant mammary tumours (poorly differentiated cancers of the 3rd grade of malignancy) with less malignant tumours (well differentiated cancers of the 1st grade of malignancy). The results of our study indicated that in dogs the number of tumour-infiltrating myeloid cells or expression of myeloid-specific antigens by cancer cells is related to the cancer progression and may constitute a new marker of malignancy, however further studies in this field are required.

Abstract A76: Comparative mRNA and microRNA expression profiling of canine mammary carcinoma cell lines and macrophages grown as a co-culture in vitro

Solid tumors comprise of various cells, including cancer cells, resident stromal cells, migratory haemopoietic cells and other. These cells regulate tumor growth and metastasis. Macrophages constitute probably the most important element of all interactions within the tumor microenvironment. However, the molecular mechanism, that guides tumor environment, still remains unknown. Exploring the underlying molecular mechanisms that orchestrate these phenomena has been the aim of our study.

The co-cultures of five various canine mammary carcinoma cell lines and macrophages were established and maintained for 72 hrs. After that, having sorted the cells, an integrated analysis of genome-wide mRNA and microRNA expression profiles have been assessed.

The analysis showed that the up-regulated genes in the cancer cell lines grown as co-culture with macrophages are involved mainly in: macrophages activation, cell motion, mammary gland development, cell-cell adhesion, and angiogenesis. Basides, the presence of macrophages in the cancer environment induces acquisition of the macrophage antigens and phenotype in cancer cells.

The up-regulated genes in macrophages grown as co-cultre with cancer cells were involved mainly in cell-cell adhesion and cell-matrix adhesion.

We found that co-culture of cancer cells and macrophages regulates expression of several important miRNAs.

Taken together, this integrated comparative study generated a scheme of the molecular changes that occur during interactions between macrophage and cancer. Because as far as we realize this is the first analysis of changes in miRNA expression in cancer cells due to a presence of macrophages, our study can serve as a valuable source for future studies on a tumor microenvironment, and some of the highlighted genes, miRNAs, pathways or processes may be useful for diagnostic or therapeutic purposes.

This work was supported by grant no N N308012939 from the Ministry of Sciences and Higher Education.

Citation Format: Magdalena Król, Karol Pawlowski, Kinga Majchrzak, Alicja Majewska, Tomasz Motyl. Comparative mRNA and microRNA expression profiling of canine mammary carcinoma cell lines and macrophages grown as a co-culture in vitro. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology: Multidisciplinary Science Driving Basic and Clinical Advances; Dec 2-5, 2012; Miami, FL. Philadelphia (PA): AACR; Cancer Res 2013;73(1 Suppl):Abstract nr A76.

Abstract A56: The number of MDSC (Gr1+/CD11b+) and T lymphocytes in blood of canine patients during mammary and skin tumors development

The very recent studies have indicated an important role of myeloid derived suppressor cells (MDSC) in the tumor progression and metastasis. They are thought to suppress the immune system and promote angiogenesis via STAT3 activation.

The aim of present study was two-fold: 1) to assess the percentage of MDSCs (CD11b+/Gr1+) in canine blood leukocytes and percentage of MDSCs that express p-STAT3 at high level; and 2) to assess the percentage of CD3+, CD4+, CD8+ and Treg (CD4+/FoxP3+) in canine blood lymphocytes collected from patients with various clinical stage of mammary and skin tumors comparing to control healthy dogs. The samples were analyzed using BD FACS AriaII.

The results of our study indicate that percentage of Gr1-positive cells is significantly increased (p&lt;0.05) in patients with stage IV tumor (4.6%, compared to control and stage I, II and III tumor: 2.38%, 0.8%, 0.65%, 1.2%, respectively). The number of Treg cells was significantly decreased (p&lt;0.001) in patients with stage III and IV tumor (1.06% and 1.03%, respectively) compared to control (4.82%), stage I and II tumor (6.5% and 3.95%, respectively). Similarly, the number of CD4+ cells was significantly decreased (p&lt;0.01 and p&lt;0.001) in stage III and IV tumors (14.8% and 2.27%, respectively) compared to control (29.84%), and stage I and II tumors (26.20% and 18.75%, respectively). Thus, the ratio of CD4/CD8 was also significantly decreased (p&lt;0.01 and p&lt;0.001) in stage III and IV tumors (respectively). The number of CD3+ cells was also significantly (p&lt;0.01) decreased in stage III and IV tumors (5.23% and 4.46%, respectively), comparing to control (11.66%), and stage I and II tumors (13.57% and 7.4%).

Our results indicate significant immunosuppression in patients with advanced tumors that can be related to high MDSCs level. High level of these cells may be also related with metastasis formation in patients with advanced tumors.

This work was supported by grant no IP2011 027171 from the Ministry of Sciences and Higher Education.

Citation Format: Joanna Mucha, Agata Homa, Kinga Majchrzak, Tomasz Motyl, Magdalena Król. The number of MDSC (Gr1+/CD11b+) and T lymphocytes in blood of canine patients during mammary and skin tumors development. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology: Multidisciplinary Science Driving Basic and Clinical Advances; Dec 2-5, 2012; Miami, FL. Philadelphia (PA): AACR; Cancer Res 2013;73(1 Suppl):Abstract nr A56.

A role of ghrelin in canine mammary carcinoma cells proliferation, apoptosis and migration

Background

Ghrelin is a natural ligand of the growth hormone secretagogue receptor (GHS-R). They are often co-expressed in multiple human tumors and related cancer cell lines what can indicate that the ghrelin/GHS-R axis may have an important role in tumor growth and progression. However, a role of ghrelin in canine tumors remains unknown. Thus, the aim of our study was two-fold: (1) to assess expression of ghrelin and its receptor in canine mammary cancer and (2) to examine the effect of ghrelin on carcinoma cells proliferation, apoptosis, migration and invasion. The expression of ghrelin and its receptor in canine mammary cancer tissues and cell lines (isolated from primary tumors and their metastases) was examined using Real-time qPCR and immunohistochemistry. For apoptosis analysis the Annexin V and propidium iodide dual staining was applied whereas cell proliferation was evaluated by MTT assay and BrdU incorporation test. The influence of ghrelin on cancer cells migration and invasion was assessed using Boyden chamber assays and wound healing assay.

Results

The highest expression of ghrelin was observed in metastatic cancers whereas the lowest expression of ghrelin receptor was detected in tumors of the 3^rd grade of malignancy. Higher expression of ghrelin and its receptor was detected in cancer cell lines isolated from metastases than in cell lines isolated from primary tumors. In vitro experiments demonstrated that exposure to low doses of ghrelin stimulates cellular proliferation, inhibits apoptosis and promotes motility and invasion of canine mammary cancer cells. Growth hormone secretagogue receptor inhibitor ([D-Lys³]-GHRP6) as well as RNA interference enhances early apoptosis.

Conclusion

The presence of ghrelin and GHS-R in all of the examined canine mammary tumors may indicate their biological role in cancer growth and development. Our experiments conducted in vitro confirmed that ghrelin promotes cancer development and metastasis.

Global gene expression profiles of canine macrophages and canine mammary cancer cells grown as a co-culture in vitro

Background

Solid tumours comprise various cells, including cancer cells, resident stromal cells, migratory haemopoietic cells and other. These cells regulate tumour growth and metastasis. Macrophages constitute probably the most important element of all interactions within the tumour microenvironment. However, the molecular mechanism, that guides tumour environment, still remains unknown. Exploring the underlying molecular mechanisms that orchestrate these phenomena has been the aim of our study.

A co-culture of canine mammary cancer cells and macrophages was established and maintained for 72 hrs. Having sorted the cells, gene expression in cancer cells and macrophages, using DNA microarrays, was examined. The results were confirmed using real-time qPCR and confocal microscopy. Moreover, their ability for migration and invasion has been assessed.

Results

Microarray analysis showed that the up-regulated genes in the cancer cell lines are involved in 15 highly over-manifested pathways. The pathways that drew our diligent attention included: the inflammation pathway mediated by chemokine and cytokine, the Toll receptor signalling pathway and the B cell activation. The up-regulated genes in the macrophages were involved in only 18 significantly over-manifested pathways: the angiogenesis, the p53 pathway feedback loops2 and the Wnt signalling pathway. The microarray analysis revealed that co-culturing of cancer cells with macrophages initiated the myeloid-specific antigen expression in cancer cells, as well as cytokine/chemokine genes expression. This finding was confirmed at mRNA and protein level. Moreover, we showed that macrophages increase cancer migration and invasion.

Conclusions

The presence of macrophages in the cancer environment induces acquisition of the macrophage phenotype (specific antigens and chemokines/cytokines expression) in cancer cells. We presumed that cancer cells also acquire other myeloid features, such as: capabilities of cell rolling, spreading, migration and matrix invasion (what has also been confirmed by our results). It may, perhaps, be the result of myeloid-cancer cell hybrid formation, or cancer cells mimicking macrophages phenotype, owing to various proteins secreted by macrophages.

Why chemotherapy can fail?

There are many reasons that lead to failure of cancer chemotherapy. Cancer has the ability to become resistant to many different types of drugs. Increased efflux of drug, enhanced repair/increased tolerance to DNA damage, high antiapoptotic potential, decreased permeability and enzymatic deactivation allow cancer cell survive the chemotherapy. Treatment can lead to the death of most tumor cells (drug-sensitive), but some of them (drug-resistant) survive and grow again. These tumor cells may arise from stem cells. There are many studies describing human experiments with multidrug resistance, especially in breast cancer. Unfortunately, studies of canine or feline ABC super family members are not as extensive as in human or mice and they are limited to several papers describing PGP in mammary cancer, cutaneous mast cell tumors and lymphoma. Multidrug resistance is one of the most significant problems in oncology today. The involvement of many different, not fully recognized, mechanisms in multidrug resistance of cancer cells makes the development of effective methods of therapy very difficult. Understanding the mechanisms of drug resistance in cancer cells may improve the results of treatment. This review article provides a synopsis of all aspects that refer to cancer cell resistance to antitumor drugs.

Surgical treatment of the tentorial and falco-tentorial junction meningiomas

INTRODUCTION

Tentorial meningiomas account for 3-7.7% of all meningiomas in surgically treated patients. In this group, the falco-tentorial meningiomas are considered to be the rarest.

CASE REPORT

The paper presents three cases of the tentorial and falco-tentorial junction meningiomas. Two of the meningiomas were of major size and with an attachment at the falco-tentorial junction, while the other was attached to the inferior notch of the tentorium. The lesions manifested as headaches and disequilibrium that persisted for many years. The Parinaud syndrome and diplopia were observed in the patient with the meningioma attachment at the inferior notch of the tentorium. One of the lesions was resected completely using an occipital bitranstentorial/falcine approach. In the second case an occipito-transtentorial approach was used. However, during the surgery problems arose with resecting the lesion on the other side. The meningioma of the inferior notch of the tentorium was vascularized through the tentorial artery stemming from the meningo-hypophyseal trunk of the intracavitary section of the internal carotid artery on the right side. This meningioma required a two-stage operation. The surgical treatment was satisfactory and depended on the patient's condition at the time of the surgery.

CONCLUSION

The presented rare cases of tentorial and falco-tentorial junction meningiomas seem to suggest that their treatment should be surgical and launched promptly after making a diagnosis. The results of the treatment might then be favourable.

[Surgical treatment of pineal and tectal tumors from the subtentorial and supracerebellar approach]

The results of operative treatment of pineal and tectal tumours by infratentorial, supracerebellar approach were presented. There were 15 patients with pineal and 2 with tectal tumours. Clinical symptoms of the disease were as follows: signs of intracranial hypertension, tectal lesion, impairment of gait and hypoacusis. Diagnostic procedure included CT, MRI, and panangiography investigation. Application of infratentorial, supracerebellar approach enabled total resection of tumours in 14 patients (82.3%) and subtotal in 2 patients (11.8%) In 1 patient we managed to do only diagnostic biopsy (5.9%). This approach makes possible removal of pineal and tectal tumours growing in the midline toward the anterior part of III ventricle and also posterior fossa. The advantage of this approach is fact that the operation takes place below the vein of Galen. Drooping by gravity cerebellum creates enough places for microsurgical operation. During control investigation 13 patients (76%) had no announce any complaints and were without neurological disorders.

[Therapeutic management of massive hemorrhage caused by gastroduodenal ulcer]

Based on 103 patients the authors discussed policy of therapeutic management in gastric and duodenal ulcer disease complicated by massive hemorrhage. In the surgical treatment of such patients the authors prefer resection procedures aimed at simultaneous control of bleeding, prevention of its relapse and radical treatment of peptic ulcer disease.

[Experimental gluing of the pleural cavity]

In experimental research on rabbits the authors assessed the usefulness of tissue adhesive-GRF in obtaining tissue union in the pleural cavity to replace aspiration drainage after thoracosurgical operations. The experiments were carried out on rabbits under general anaesthesia in two groups. First group had thoracotomy and after expansion of the lungs the chest was closed tightly. In second group after thoracotomy the lungs were stabilized with gelatin-resorcin-formaldehyde glue. Aspiration drainage was not used. The observation included: radiologic examination, measurements of pulmonary ventilation using Wright's volumometer and gasometric determination. Moreover the alveolar-capillary oxygen difference and the percent of lung shunt were determined. The authors underline good function glued lungs.