Breast Cancer Cell-Derived Adenosine Enhances Generation and Suppressor Function of Human Adaptive Regulatory T Cells

Introduction: Adaptive regulatory T cells (Tr1) are induced in the periphery by environmental stimuli. CD73 expression and adenosine (ADO) production by tumor cells may influence Tr1 generation and their immunosuppressive activity. Material and Methods: Tr1 were generated in co-cultures of CD4+CD25neg T cells, autologous immature dendritic cells (iDC), and irradiated ADO-producing CD73+ or non-producing CD73neg breast cancer (BrCa) cell lines (TU). The expression of ectonucleotidases and other surface markers on Tr1 was determined by flow cytometry. Tr1-mediated suppression of proliferation was evaluated in CFSE-based assays. Luciferase-based ATP detection assays and mass spectrometry were used to measure ATP hydrolysis and ADO levels. Cytokine levels were measured by ELISA or Luminex. CD73 expression on tumor cells or T cells in TU tissues was assessed by immunofluorescence. Results: CD73+ TU induced higher numbers of Tr1 cells (p < 0.01) than CD73neg TU. Tr1TU73+ hydrolyzed more exogenous ATP, produced more ADO, and mediated higher suppression than Tr1TU73neg (p < 0.05 for all). ARL67156, an ectonucleotidase inhibitor, and ZM241385, A2A receptor antagonist, reduced suppression of proliferation mediated by Tr1TU73+ cells (p < 0.01). Basal-like primary BrCa cells expressed higher levels of ectonucleotidases and induced more Tr1 than less aggressive primary luminal-like BrCa. Conclusion: BrCa producing ADO (CD73+ TU) favor the induction of Tr1, which expresses CD39 and CD73, hydrolyzes ATP to ADO, and effectively suppresses anti-tumor immunity.

CD26 expression and adenosine deaminase activity in regulatory T cells (Treg) and CD4(+) T effector cells in patients with head and neck squamous cell carcinoma

Adenosine deaminase (ADA) is responsible for the deamination of immunosuppressive adenosine to inosine. In human T lymphocytes, ADA is associated with dipeptidyl peptidase IV (CD26). ADA expression and activity were evaluated in regulatory T cells (Treg) and CD4(+) T effector cells (Teff) of patients with head and neck squamous cell cancer (HNSCC). CD4(+)CD39(+) and CD4(+)CD39(neg) T cells were isolated by single-cell sorting from the peripheral blood of 15 HNSCC patients and 15 healthy donors (NC). CD26/ADA expression in these cells was studied by multicolor flow cytometry, confocal microscopy, RT-PCR and immunohistochemistry in tumor tissues. ADA activity was evaluated by mass spectrometry, suppression of Teff proliferation in CFSE assays and cytokine production by Luminex. CD4(+)CD39(+) Treg had low and CD4(+)CD39(neg) Teff high CD26/ADA expression and ADA activity in NC or HNSCC. The frequency and suppressor activity of CD39(+)CD26(neg) Treg were elevated in patients relative to NC (p < 0.01). However, ADA activity in patients' CD4(+)CD39(neg) Teff was decreased (p < 0.05), resulting in extracellular adenosine accumulation. Also, patients' Teff were more sensitive to inhibitory signals delivered via adenosine receptors. IL-2, IL12 and INFγ upregulated ADA expression and activity in CD4(+)CD39(neg) Teff, whereas IL-10, PGE(2) and CADO downregulated it. The differentially expressed CD26/ADA can serve as surface markers for functionally-active CD39(+)CD26(neg) Treg.

Differential chemokine expression patterns in tonsillar disease

Expression profiles of CXC- and CC-chemokines in various forms of tonsillar disease were studied to evaluate whether certain chemokines play a predominant role in a specific subset of tonsillar disease. Total RNA was isolated from 89 biopsies (21 hyperplastic palatine tonsils, 25 adenoids, 16 chronic inflammatory palatine tonsils and 27 chronic inflammatory palatine tonsils with histological prove of acute inflammation), reverse transcribed and subjected to PCR amplifying IL-8, Gro-alpha, eotaxin-1, eotaxin-2, MCP-3, MCP-4 and RANTES. 2% agarose gel electrophoresis revealed a predominance of IL-8 in the chronic inflammatory palatine tonsil group compared to tonsillar hyperplasia. Furthermore, eotaxin-2 was strongly overexpressed in adenoid samples compared to chronic inflammatory specimens. Our data suggest that the majority of diseases related to adenoid formation are mediated via an eotaxin-2 expression, whereas chronic inflammatory tonsillitis is associated with IL-8 upregulation. These data imply that adenoids are related to a Th-2, and chronic inflammatory tonsillitis to a Th-1 based immune response.

Ectonucleotidase CD39 expression in regional metastases in head and neck cancer

INTRODUCTION

CD39 is the rate-limiting enzyme in the generation of immunosuppressive adenosine and its expression and activity are significant in tumor progression. Squamous cell carcinoma of the head and neck (HNSCC) shows an overall poor prognosis due to high local recurrence rates and early metastatic spread.

MATERIAL AND METHODS

Primary tumor specimens and lymph node specimens harvested during neck dissection of 65 patients with a diagnosis of HNSCC were subjected to immunohistochemical and H-score analysis of CD39 expression. Demographics, histopathology and subsequent outcome were analyzed.

RESULTS

The primary cancer was squamous cell carcinoma in all patients (male/female 55:10). H-score for CD39 expression in the primary lesion and metastatic lymph nodes was significantly higher in advanced compared to early stages with no significant differences among different tumor locations. High intratumoral and intrametastatic CD39 expression was associated with an inferior patients' overall survival at a mean follow-up of 83.4 months (6-204 months).

CONCLUSION

CD39 expression in HNSCC correlated positively with tumor stage and appears to predict poor prognosis. Therefore, CD39 expression in primary lesions and metastatic lymph nodes seems to identify patients at high risk in HNSCC of all tumor sites. Immunotherapeutic approaches targeting CD39 might be promising for this patient population.

CD31 and VEGF are prognostic biomarkers in early-stage, but not in late-stage, laryngeal squamous cell carcinoma

Background

Patients suffering from squamous cell carcinoma of the larynx (LSCC) with lymphatic metastasis have a relatively poor prognosis and often require radical therapeutic management. The mechanisms which drive metastasis to the lymph nodes are largely unknown but may be promoted by a pro-angiogenic tumor microenvironment. In this study, we examined whether the number of microvessels and the expression level of vascular endothelial growth factor (VEGF) in the primary tumor are correlated with the degree of lymph node metastasis (N-stage), tumor staging (T) and survival time in LSCC patients.

Methods

Tissue-Microarrays of 97 LSCC patients were analyzed using immunohistochemistry. The expression of VEGF was scored as intensity of staining (low vs high) and the number of CD31-positive vessels (median </≥7 vessels per visual field) was counted manually. Scores were correlated with N-stage, T-stage and 5-year overall survival rate.

Results

A high expression of angiogenic biomarkers was not associated with poor overall survival in the overall cohort of patients. Instead high CD31 count was associated with early stage cancer (p = 0.004) and in this subgroup high VEGF expression correlated with poor survival (p = 0.032). Additionally, in early stage cancer a high vessel count was associated with an increased recurrence rate (p = 0.004).

Conclusion

Only in the early stage subgroup a high expression of angiogenic biomarkers was associated with reduced survival and an increased rate of recurrence. Thus, biomarkers of angiogenesis may be useful to identify high risk patients specifically in early stage LSCC.

CD73 expression in lymph node metastases in patients with head and neck cancer

INTRODUCTION

CD73 is an enzyme crucial in the metabolism of immunosuppressive adenosine. In cancer, it has various functions including tumor growth and metastases. Squamous cell carcinoma of the head and neck has an overall poor prognosis, also due to early spread of metastatic cells.

MATERIALS AND METHODS

Tumor and lymph node specimens of 65 patients with HNSCC were subjected to immunohistochemical and H-score analysis of CD73 expression. Demographics, diagnoses, histopathology and subsequent outcome were analyzed.

RESULTS

The primary cancer was squamous cell carcinoma in all patients (male/female 55:10) with the following locations: oral cavity n:16, oropharynx n:28, hypopharynx n:11 and larynx n:10. H-score for CD73 expression in the primary lesion and metastatic lymph nodes was significantly higher in advanced compared to early stages with no significant differences among tumor locations. High CD73 expression was associated with reduced overall survival rates at a mean follow-up of 83.4 months (6-204 months).

CONCLUSIONS

CD73 expression in HNSCC correlated positively with tumor stage and was associated with poor prognosis. Therefore, CD73 expression in primary lesions and regional metastases appears to predict HNSCC patients at high risk of all tumor sites. Therapeutic approaches targeting CD73 might seem promising for this patient population.

Foxp3 expression in lymph node metastases in patients with head and neck cancer

INTRODUCTION

The prevalence and activity of regulatory T cells in patients with cancer correlates with poor prognosis. These cells are characterized by their expression of Forkhead box protein-3 (Foxp3). Squamous cell carcinoma is the most prevalent type of cancer in the head and neck region with overall poor survival rates, also due to early spread of metastatic cells.

MATERIAL AND METHODS

Primary tumor specimens as well as lymph node specimens harvested during neck dissection of 65 patients with a diagnosis of HNSCC were subjected to immunohistochemical and H-score analysis of Foxp3 expression. Demographics, diagnoses, histopathology and subsequent outcome were analyzed.

RESULTS

The primary cancer was squamous cell carcinoma in all patients (male/female 55:10) with the following tumor locations: oral cavity n = 16, oropharynx n = 28, hypopharynx n = 11 and larynx n = 10 (Stage III n = 18; Stage IVA n = 45; Stage IVB n = 2). The H-score for Foxp3 expression in the primary lesion as well as metastatic lymph nodes was significantly higher in advanced stages compared to early stages with differences among tumor locations, which were not significant. High Foxp3 expression was associated with inferior overall survival rates at a mean follow-up of 83.4 months (6-204 months) Conclusions: Foxp3 expression in HNSCC varied from the anatomical site and correlated positively with tumor stage and was associated with poor prognosis. Therefore, Foxp3 expressions in primary lesions as well as lymphogenic metastases appear to predict high-risk HSNCC patients. Novel therapeutic approaches targeting Foxp3⁺ cells might seem promising for this patient population.

Indications of cone beam CT in head and neck imaging in children

For imaging of bony structures, especially for the anterior and lateral skull base in ORL medicine, cone beam computed tomography (CBCT) is an increasingly used alternative to CT, with a lower exposition to plain radiography that makes its use for imaging, particularly in children, very interesting. The aim of this study was to analyse possible indications and settings for CBCT in children and compare them to those of adults. A total of 554 patients (age range 0-18 years, mean age 10.36 years), who underwent CBCT between 01/2004-06/2013 in the ENT department at the university clinic of Marburg were enrolled in this retrospective analysis to evaluate technical parameters and indications. Data on CBCT of all children were compared with previously published data collected from 1730 adults who were diagnosed with the help of CBCT in the ENT department at the university clinic of Marburg, during the years 2012-2013. The most frequent indications of CBCT in children vs. adults were in the anterior skull base region: mid-facial trauma (60.4%) vs. chronic rhinosinusitis (54.8%), disturbed nasal breathing (13.9% vs. 13.0%) and chronic rhinosinusitis (12%) vs. mid-facial trauma (10.8%). For the lateral skull base the main indications were cholesteatoma (20.3%) vs. position control of cochlear implant (CI) electrode (31.2%), chronic otorrhoea (17.5%) vs. cholesteatoma (20.9%), and position control of CI electrode (11.8%) vs. chronic otitis media mesotympanalis (6.8%). CBCT is a suitable imaging modality for bony structures in adults and children. Settings mainly depend on the region of interest. One aim should also be to reduce exposure to radiation in both adults and children.

Evaluation of different time schedules in training with the Da Vinci simulator

BACKGROUND

This prospective study analyzed the effect of different time schedules in training on the main performance outcomes: overall score, time to complete, and economy of motion.

METHODS

The study was performed on the da Vinci Skills Simulator from December 2014 to April 2016. Forty robotic novices were randomized into two groups of 20 participants, which trained in the same three exercises but with different intervals between their training sessions. Each group performed training in Peg Board 1 in their first week, Match Board 2 in their second week, and Ring and Rail 2 in their third week. On their last day, Needle Targeting and Energy Dissection 2, for which no previous training had been received, were performed. Regarding the different training intervals, group 1 trained each exercise six times in a row once a week. Group 2 performed their training once a day for 5 days. Technical performance parameters were recorded by the Mimics simulator software for further analysis. In addition, the participants were asked to fill out a questionnaire concerning the robotics training.

RESULTS

Group 2 performed significantly better compared to group 1 in the main metrics in the more advanced exercises. For the easier exercises, the training frequency did not lead to significant differences in performance outcome. A significant skills gain was seen between the first and last training sessions for all exercises in both groups.

CONCLUSIONS

Performance in the final exercise NT was significantly better in group 2 than group 1. Regarding ED 2, no difference was found between the two groups. As the training of group 2 led to significantly better outcomes, we suggest that, especially for advanced exercises, it seems to be more favorable to perform training every day for a short period than to train once a week six times in a row.

A european multicenter study evaluating the flex robotic system in transoral robotic surgery

OBJECTIVES/HYPOTHESIS

To evaluate the application of the Flex Robotic System in transoral robotic surgery (TORS).

STUDY DESIGN

Multicenter, prospective, open-label, single-armed clinical study.

METHODS

A prospective clinical follow-up multicenter study was performed from July 2014 to October 2015 assessing the safety and efficacy of the Medrobotics Flex Robotic System for access and visualization of the oropharynx, hypopharynx, and larynx as well as for resection of benign and malignant lesions. A total of 80 patients were enrolled. Access and visualization of five anatomic subsites (base of tongue, palatine tonsil area, epiglottis, posterior pharyngeal wall, and false vocal cords) were individually graded by the surgeon. Setup times, access and visualization times, surgical results, and adverse events were documented.

RESULTS

The relevant anatomic structures could be exposed and visualized properly in 75 patients, who went on to have a surgical procedure performed with the Flex Robotic System. Access and visualization of the palatine tonsil area, posterior pharyngeal wall, epiglottis, and posterior pharyngeal wall were excellent. However, false vocal cords and vocal cords were more difficult to expose. Seventy-two patients were treated successfully with the Flex Robotic System. There were no serious or unanticipated device-related adverse events caused by the Flex Robotic System.

CONCLUSIONS

Lesions in the oropharynx, hypopharynx, and larynx could be successfully resected with the Flex Robotic System, specifically developed for TORS. Our study provides evidence that the Flex Robotic System is a safe and effective tool in TORS. Laryngoscope, 2016 127:391-395, 2017.

Utility of the Highly Articulated Flex Robotic System for Head and Neck Procedures: A Cadaveric Study

OBJECTIVE

Robotic head and neck surgery potentially reduces the morbidity associated with traditional open procedures. This study's goal was to employ a novel highly articulated robotic system (Flex Robotic System) for head and neck procedures, including a postauricular facelift approach thyroidectomy, submandibular gland (SMG) removal, and cervical lymphadenectomy.

STUDY DESIGN

It was hypothesized that the Medrobotics Flex Robotic System could be used for transcervical head and neck surgical procedures.

METHODS

Three fresh upper body human cadavers were used. The Flex Robotic System was used to complete a thyroidectomy, neck dissection, and SMG removal on each cadaver.

RESULTS

A postauricular incision and flap was manually raised. The robotic system was positioned on the right side of the cadaver's head. The system's manually controlled flexible instruments and highly shapeable, robot-assisted scope were used to perform a thyroid lobectomy. Neck dissection and SMG removal were also performed.

CONCLUSIONS

Although a promising technology, the current robotic system (Intuitive Surgical Inc, Sunnyvale, California, USA) has limitations due to its rigid and large configuration, which decreases exposure and access. The new system's shapeable, computer-assisted scope seeks to reduce some of these difficulties and may be better adapted for transcervical approaches to the neck operations.

Structured training on the da Vinci Skills Simulator leads to improvement in technical performance of robotic novices

BACKGROUND

The increasing use of minimally invasive techniques such as robotic-assisted devices raises the question of how to acquire robotic surgery skills. The da Vinci Skills Simulator has been demonstrated to be an effective training tool in previous reports. To date, little data are available on how to acquire proficiency through simulator training. We investigated the outcome of a structured training programme for robotic surgical skills by robotic novices.

METHODS

This prospective study was conducted from January to December 2013 using the da Vinci Skills Simulator. Twenty participants, all robotic novices, were enrolled in a 4-week training curriculum. After a brief introduction to the simulator system, three consecutive repetitions of five selected exercises (Match Board 1, 2, 3 and Ring and Rail 1, 2) were performed in a defined order on days 1, 8, 15 and 22. On day 22, one repetition of a previously unpractised more advanced module (Needle Targeting) was also performed. After completion of each study day, the overall performance, time to completion, economy in motion, instrument collisions, excessive instrument force, instruments out of view, master workspace range and number of drops were analysed.

RESULTS

Comparing the first and final repetition, overall score and time needed to complete all exercises, economy of motion and instrument collisions were significantly improved in nearly all exercises. Regarding the new exercise, a positive training effect could be demonstrated. While its overall entry score was significantly higher, the time to completion and economy of motion were significantly lower than the scores on the first repetition of the previous 5 exercises.

CONCLUSIONS

It could be shown that training on the da Vinci Skills Simulator led to an improvement in technical performance of robotic novices. With regard to a new exercise, the training had a positive effect on the technical performance.

Mutant KRAS Conversion of Conventional T Cells into Regulatory T Cells

Constitutive activation of the KRAS oncogene in human malignancies is associated with aggressive tumor growth and poor prognosis. Similar to other oncogenes, KRAS acts in a cell-intrinsic manner to affect tumor growth or survival. However, we describe here a different, cell-extrinsic mechanism through which mutant KRAS contributes to tumor development. Tumor cells carrying mutated KRAS induced highly suppressive T cells, and silencing KRAS reversed this effect. Overexpression of the mutant KRAS(G12V)gene in wild-type KRAS tumor cells led to regulatory T-cell (Treg) induction. We also demonstrate that mutant KRAS induces the secretion of IL10 and transforming growth factor-β1 (both required for Treg induction) by tumor cells through the activation of the MEK-ERK-AP1 pathway. Finally, we report that inhibition of KRAS reduces the infiltration of Tregs in KRAS-driven lung tumorigenesis even before tumor formation. This cell-extrinsic mechanism allows tumor cells harboring a mutant KRAS oncogene to escape immune recognition. Thus, an oncogene can promote tumor progression independent of its transforming activity by increasing the number and function of Tregs. This has a significant clinical potential, in which targeting KRAS and its downstream signaling pathways could be used as powerful immune modulators in cancer immunotherapy.

Effect of training frequency on the learning curve on the da Vinci Skills Simulator

BACKGROUND

The purpose of this study was to evaluate the effect of training on the performance outcome with the da Vinci Skills Simulator.

METHODS

Forty novices were enrolled in a prospective training curriculum. Participants were separated into 2 groups. Group 1 performed 4 training sessions and group 2 had 2 training sessions over a 4-week period. Five exercises were performed 3 times consecutively. On the last training day, a new exercise was added.

RESULTS

A significant skills gain from the first to the final practice day in overall performance, time to complete, and economy of motion was seen for both groups. Group 1 had a significantly better outcome in overall performance, time to complete, and economy of motion in all exercises. There was no significant difference found regarding the new exercise in group 1 versus group 2 in nearly all parameters.

CONCLUSION

Longer time distances between training sessions are assumed to play a secondary role, whereas total repetition frequency is crucial for improvement of technical performance. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1762-E1769, 2016.

Human CD4+ CD39+ regulatory T cells produce adenosine upon co-expression of surface CD73 or contact with CD73+ exosomes or CD73+ cells

While murine CD4(+) CD39(+) regulatory T cells (T(reg)) co-express CD73 and hydrolyze exogenous (e) adenosine triphosphate (ATP) to immunosuppressive adenosine (ADO), surface co-expression of CD73 on human circulating CD4(+) CD39(+) T(reg) is rare. Therefore, the ability of human T(reg) to produce and utilize ADO for suppression remains unclear. Using mass spectrometry, we measured nucleoside production by subsets of human CD4(+) CD39(+) and CD4(+) CD39(-)CD73(+) T cells or CD19(+) B cells isolated from blood of 30 volunteers and 14 cancer patients. CD39 and CD73 expression was evaluated by flow cytometry, Western blots, confocal microscopy or reverse transcription-polymerase chain reaction (RT-PCR). Circulating CD4(+) CD39(+) T(reg) which hydrolyzed eATP to 5'-AMP contained few intracytoplasmic granules and had low CD73 mRNA levels. Only ∼1% of these T(reg) were CD39(+) CD73(+) . In contrast, CD4(+) CD39(neg) CD73(+) T cells contained numerous CD73(+) granules in the cytoplasm and strongly expressed surface CD73. In vitro-generated T(reg) (Tr1) and most B cells were CD39(+) CD73(+) . All these CD73(+) T cell subsets and B cells hydrolyzed 5'-AMP to ADO. Exosomes isolated from plasma of normal control (NC) or cancer patients carried enzymatically active CD39 and CD73(+) and, when supplied with eATP, hydrolyzed it to ADO. Only CD4(+) CD39(+) T(reg) co-incubated with CD4(+) CD73(+) T cells, B cells or CD39(+) CD73(+) exosomes produced ADO. Thus, contact with membrane-tethered CD73 was sufficient for ADO production by CD4(+) CD39(+) T(reg). In microenvironments containing CD4(+) CD73(+) T cells, B cells or CD39(+) CD73(+) exosomes, CD73 is readily available to CD4(+) CD39(+) CD73(neg) T(reg) for the production of immunosuppressive ADO.

Prognostic value of level IV metastases from head and neck squamous cell carcinoma

BACKGROUND

The purpose of this study was to evaluate the prognostic value of level IV metastases in head and neck squamous cell carcinoma (HNSCC).

METHODS

The clinical and histopathological data of 111 patients with HNSCC with pN+ neck who underwent a primary tumor resection with unilateral or bilateral neck dissection were analyzed.

RESULTS

Level IV metastases were histopathologically proven in 33 patients (29.7%). Pulmonary metastases were observed in 12 of 33 patients (36.4%) with level IV metastases, and in 13 of 78 patients (16.7%) without level IV metastases (p = .04). Multivariate analyzes revealed a significant association between level IV metastases and pulmonary metastases (p = .038). However, an influence on overall (p = .65) or disease-free survival (p = .66) was not observed.

CONCLUSION

Level IV metastases seem to be a predictive factor for pulmonary metastases but not for overall and disease-free survival in patients with HNSCC.

[Penetrating injuries of the head and neck region - a potentially life threatening situation]

Penetrating Injuries of the Head and Neck Region - A Potentially Life Threatening Situation Background: Cuts, stabs and gunshot wounds in the head and neck region are potentially life-threatening because of the high risk of vascular lesions. A consistent emergency management is usually based on an operative exploration of the wound with effective reconstruction of viable structures.

PATIENTS AND METHODS

Various penetrating injuries of the head and neck region are described in 11 cases with respect of age, gender, course of events of injury, type of injury, involved structures, diagnostic and operative procedures and outcome and compared with current literature and guidelines.

RESULTS

In 10 of 11 patients, in the context of an interdisciplinary emergency room management, CT angiography was performed following clinical examination. A surgical exploration and wound treatment was performed in 9 of these patients. The common carotid artery, the external carotid artery and large venous blood vessels of the neck were injured in 2 cases respectively. None of the patients deceased or suffered permanent damage.

CONCLUSION

The outcome of deep head and neck lesions with relevant vascular trauma is determined by a rapid and interdisciplinary approach. A rapid, systematic and interdisciplinary approach in specialized trauma centers has a significant role in ensuring that patients with penetrating wounds in the head and neck -region rarely die due to their serious injury or their consequences.

Establishing a transoral robotic surgery program in an academic hospital in Germany

The application of robot technology in the field of surgery has grown rapidly in recent years. Also in Europe, robot-assisted surgery has become increasingly popular, predominantly in the fields of urology and gynecology. Transoral robotic surgery (TORS) is widely practiced in North America after receiving FDA approval in 2009. This technique was also adopted and is being practiced at specialized institutions in various European countries, including Germany. Due to significant differences in the health-care system and divergent developments of the use of transoral surgery in the treatment of laryngeal and pharyngeal malignancies in the last decade between North America and Europe, there are unique barriers and challenges to introducing TORS in these two parts of the world. This article describes experiences in developing a TORS program at an academic hospital in Germany. Specifically, steps that were required to obtain institutional approval and financial support, as well as to train surgeons and allied health-care personnel, and to establish a sufficient and adequate technique for reprocessing the used instruments are presented. Introducing a TORS program in Europe is still a challenge in regard to financial issues, acceptance, and practicability and therefore it is only practiced in specialized centers, although systems are widely available and often used in the same hospital by urology departments.

Freehand SPECT for sentinel lymph node detection in patients with head and neck cancer: first experiences

CONCLUSION

Feasibility of intraoperative 3D imaging with freehand (fh) SPECT for sentinel lymph node (SLN) biopsy in head and neck cancer (HNC) could be demonstrated. Controlled clinical studies are needed to evaluate its accuracy and impact on patient morbidity.

OBJECTIVES

The clinical N0 neck in HNC needs improvement in management to sufficiently detect occult neck disease but to spare patients from potential morbidity by elective neck dissection. The SLN concept has potential to accurately stage the neck with low morbidity.

METHODS

fhSPECT is a 3D tomographic imaging modality with a gamma probe system combined with an infrared optical tracking system. Five patients with HNC and clinical N0 neck were recruited. Scanning for SLN using fhSPECT was performed before excision and selective neck dissection and specimens were analyzed histopathologically.

RESULTS

Preoperatively, a total of nine SLNs were located in five patients with fhSPECT. SLNs in three patients were positive for metastatic disease; in two patients the SLNs were tumor-free. No residual radioactivity was found in the neck in any of the patients after extirpation of SLNs. fhSPECT acquisitions took 2.6 ± 0.4 min. No metastatic lymph nodes were detected in any other node harvested during subsequent selective neck dissection in any patients.

Differences of radiological artefacts in cochlear implantation in temporal bone and complete head

OBJECTIVES

Accurate radiological evaluation of cochlear implants is essential for improvement of devices and techniques and also for assessing the position of the electrodes within the cochlea. Radiological study of implants has focused on isolated temporal bones. Previous studies showed relevant sizes of artefacts (dimensions of the radiological image compared with the actual dimensions of the electrode) in visualization of cochlear implants in computed tomography and cone beam computed tomography (CBCT). In this study, we aimed to obtain CBCT images of cochlear electrodes in isolated temporal bones and in whole heads and to assess the differences in image quality between the two.

METHODS

Cochlear electrodes were implanted in three complete human heads. Radiological examinations were performed using a single CBCT scanner with varying x-ray tube currents, voltages, and rotation angles. The temporal bones were then removed and the same radiological examinations were repeated, with and without the receiver coils. Artefacts from a basal electrode (electrode 9) and an apical electrode (electrode 2) were calculated. These were compared with each other by measuring the diameter of the image of the electrode (electrode inclusive of imaging artefacts) and with the real electrode diameters from the manufacturer's data. Additionally, the radiological diameters (inclusive of artefact) of the electrodes were compared to the cross-sectional diameters of the basal and apical coils of the cochlea at the locations of these two electrodes.

RESULTS

In comparison to the real electrode diameters, radiological artefact proportions of 51-58% for electrode 9 and 56-61% for electrode 2 were calculated. The differences between whole head images (group 1) and temporal bone images with and without the receiver coil (groups 2 and 3) were highly significant for each protocol (P < 0.001).

DISCUSSION AND CONCLUSION

These results indicate that it is not possible reliably to determine the exact intracochlear positions of electrodes using CBCT. Imaging of isolated temporal bones produced significantly greater artefacts than imaging of the whole head. Evaluations of image quality based only on results for isolated temporal bones are not transferable to clinical situations, and should be assessed critically.

Generation and immunosuppressive functions of p53-induced human adaptive regulatory T cells

Inducible regulatory T cells (iTregs, also called Tr1 cells) are generated in the periphery (circulation or tissue) of cancer patients upon the encounter of naïve CD4⁺ T cells with tumor-associated antigens. As p53 is often inactivated by genetic or epigenetic events during oncogenesis, p53-induced Tr1 cells might play a key role in establishing immunosuppressive networks in cancer patients. Tr1 cells were generated by co-culturing circulating CD4⁺CD25⁻ T cells with autologous immature dendritic cells pulsed with a wild-type (WT) p53-derived peptide or an unrelated peptide derived from mucin 1 (MUC1). The Tr1 phenotype and the specificity for p53 of these cells were confirmed by multicolor flow cytometry. Moreover, the Tr1 cell-mediated suppression of T-cell proliferation was evaluated by CFSE-based flow cytometry, while their ability to alter the T-cell cytokine profile by ELISA and Luminex assays. The capacity of p53-induced Tr1 cells to suppress the generation and function of cytotoxic T lymphcoytes (CTLs) was assessed by flow cytometry and ELISPOT. Of note, low doses of the p53-derived peptide (p53_low) induced greater numbers of Tr1 cells than the same peptide employed at high doses (p53_high). Moreover, Tr1/p53_low cells not secreted higher levels of interleukin-10 and transforming growth factor β1, but also mediated more robust suppressive effects on CTL proliferation than Tr1/p53_high cells. Tr1/p53_low cells, Tr1/p53_high cells, as well as Tr1 cells generated with low doses of an unrelated MUC1-derived peptide were equally effective in suppressing the expansion and antitumor activity of p53-reactive CTLs. p53_low induced the expansion of highly suppressive p53-reactive Tr1 cells. However, the capacity of these Tr1 cells to suppress the generation and function of p53-reactive CTLs was independent of their antigen-specificity.

The role of the adenosinergic pathway in immunosuppression mediated by human regulatory T cells (Treg)

Tumor-induced dysfunction of immune cells is a common problem in cancer. Tumors induce immune suppression by many different mechanisms, including accumulation of regulatory T cells (Treg). Adaptive Treg (Tr1) generated in the tumor microenvironment express CD39 and CD73 ectonucleotidases, produce adenosine and are COX2+PGE2+. Adenosine and PGE2 produced by Tr1 or tumor cells bind to their respective receptors on the surface of T effector cells (Teff) and cooperate in up-regulating cytosolic 3'5'-cAMP levels utilizing adenylyl cyclase isoform 7 (AC-7). In Teff, increased cAMP mediates suppression of anti-tumor functions. Treg, in contrast to Teff, seem to require high cAMP levels for mediating suppression. This differential requirement of Treg and Teff for cAMP offers an opportunity for pharmacologic interventions using selected inhibitors of the adenosine/PGE2 pathways. Blocking of adenosine/PGE2 production by Tr1 or blocking binding of these factors to their receptors on T cells or inhibition of cAMP synthesis in Teff all represent novel therapeutic strategies that used in combination with conventional therapies could restore anti-tumor functions of Teff . At the same time, these inhibitors could disarm Tr1 cells by depriving them of the factors promoting their generation and activity or by down-regulating 3'5'-cAMP levels. Thus, the pharmacologic control of Treg-Teff interactions offers a novel strategy for restoration of anti-tumor Teff functions and silencing of Treg. Used in conjunction with anti-cancer drugs or with immune therapies, this strategy has a potential to improve therapeutic effects by preventing or reversing tumor-induced immune suppression.

Targeting human inducible regulatory T cells (Tr1) in patients with cancer: blocking of adenosine-prostaglandin E₂ cooperation

INTRODUCTION

Emerging data suggest that human inducible regulatory T cells (Tr1) produce adenosine and prostaglandin E(2) and that these factors cooperate in mediating immune suppression.

AREAS COVERED

Human Tr1 present in human tumors or blood of cancer patients express ectonucleotidases, CD39 and/or CD73, hydrolyze ATP to adenosine and are COX-2 positive. Expression of CD39 and/or CD73 on human tumors favors expansion and suppressor functions of Tr1. Adenosine and PGE(2) signal via adenosine 2A receptor (A(2A)R) and prostaglandin E(2) receptor 2 (EP(2)R) expressed on effector T (Teff) cells, suppressing their anti-tumor functions by a common mechanism involving upregulation of cytosolic cAMP levels and protein kinase A (PKA) type I activation. The frequency and activity of circulating CD4(+)CD39(+) and CD4(+)COX-2(+) Treg subsets increase in advanced disease and also following oncologic therapies.

EXPERT OPINION

Pharmacologic blocking of adenosine-PGE(2) collaboration provides a clinically-feasible strategy for disarming of Treg. Used in conjunction with conventional anti-cancer drugs or immune interventions, pharmacologic inhibitors could improve outcome of oncologic therapies.

Adenosine and prostaglandin E2 cooperate in the suppression of immune responses mediated by adaptive regulatory T cells

Adaptive regulatory T cells (Tr1) are induced in the periphery upon encountering cognate antigens. In cancer, their frequency is increased; however, Tr1-mediated suppression mechanisms are not yet defined. Here, we evaluate the simultaneous involvement of ectonucleotidases (CD39/CD73) and cyclooxygenase 2 (COX-2) in Tr1-mediated suppression. Human Tr1 cells were generated from peripheral blood mononuclear cell-derived, sorted CD4(+)CD25(-) T cells and incubated with autologous immature dendritic cells, irradiated COX-2(+) or COX-2(-) tumor cells, and IL-2, IL-10, and IL-15 (each at 10-15 IU/ml) for 10 days as described (Bergmann, C., Strauss, L., Zeidler, R., Lang, S., and Whiteside, T. L. (2007) Cancer Immunol. Immunother. 56, 1429-1442). Tr1 were phenotyped by multicolor flow cytometry, and suppression of proliferating responder cells was assessed in carboxyfluorescein diacetate succinimidyl ester-based assays. ATP hydrolysis was measured using a luciferase detection assay, and levels of adenosine or prostaglandin E(2) (PGE(2)) in cell supernatants were analyzed by mass spectrometry or ELISA, respectively. Intracellular cAMP levels were measured by enzyme immunoassay. The COX-2(+) tumor induced a greater number of Tr1 than COX-2(-) tumor (p < 0.05). Tr1 induced by COX-2(+) tumor were more suppressive, hydrolyzed more exogenous ATP (p < 0.05), and produced higher levels of adenosine and PGE(2) (p < 0.05) than Tr1 induced by COX-2(-) tumor. Inhibitors of ectonucleotidase activity, A(2A) and EP(2) receptor antagonists, or an inhibitor of the PKA type I decreased Tr1-mediated suppression (p < 0.05), whereas rolipram, a PDE(4) inhibitor, increased the intracellular cAMP level in responder cells and their susceptibility to Tr1-mediated suppression. Tr1 present in tumors or the peripheral blood of head and neck squamous cell carcinoma patients co-expressed COX-2, CD39, and CD73. A concomitant inhibition of PGE(2) and adenosine via the common intracellular cAMP pathway might be a novel approach for improving results of immune therapies for cancer.

TLR4 signaling induced by lipopolysaccharide or paclitaxel regulates tumor survival and chemoresistance in ovarian cancer

Toll-like receptors (TLRs) expressed on immune cells trigger inflammatory responses. TLRs are also expressed on ovarian cancer (OvCa) cells, but the consequences of signaling by the TLR4/MyD88 pathway in these cells are unclear. Here, TLR4 and MyD88 expression in OvCa tissues (n=20) and cell lines (OVCAR3, SKOV3, AD10, A2780 and CP70) was evaluated by reverse transcriptase-PCR, western blots and immunohistochemistry. Cell growth, apoptosis, nuclear factor-kappaB (NF-kappaB) translocation, IRAK4 and TRIF expression and cJun phosphorylation were measured following tumor cell exposure to the TLR4 ligands, lipopolysaccharide (LPS) or paclitaxel (PTX). Culture supernatants were tested for cytokine levels. TLR4 was expressed in all tumors, tumor cell lines and normal epithelium. MyD88 was detectable in tumor tissues and in 3/5 OvCa lines but not in normal cells. In MyD88(+) SCOV3 cells, LPS or PTX binding to TLR4 induced IRAK4 activation and cJun phosphorylation, activated the NF-kappaB pathway and promoted interleukin (IL)-8, IL-6, vascular endothelial growth factor and monocyte chemotactic protein-1 production and resistance to drug-induced apoptosis. Silencing of TLR4 in SCOV3 cells with small interference RNA resulted in phosphorylated-cJun (p-cJun) downregulation and a loss of PTX resistance. In PTX-sensitive, MyD88(neg) A2780 cells, TLR4 stimulation upregulated TRIF, and TLR4 silencing eliminated this effect. Thus, TLR4/MyD88 signaling supports OvCa progression and chemoresistance, promoting immune escape.

Generation and accumulation of immunosuppressive adenosine by human CD4+CD25highFOXP3+ regulatory T cells

Naturally occurring regulatory T cells (nTreg) are crucial for maintaining tolerance to self and thus preventing autoimmune diseases and allograft rejections. In cancer, Treg down-regulate antitumor responses by several distinct mechanisms. This study analyzes the role the adenosinergic pathway plays in suppressive activities of human nTreg. Human CD4(+)CD25(high)FOXP3(+) Treg overexpress CD39 and CD73, ectonucleotidases sequentially converting ATP into AMP and adenosine, which then binds to A(2a) receptors on effector T cells, suppressing their functions. CD4(+)CD39(+) and CD4(+)CD25(high) T cells express low levels of adenosine deaminase (ADA), the enzyme responsible for adenosine breakdown, and of CD26, a surface-bound glycoprotein associated with ADA. In contrast, T effector cells are enriched in CD26/ADA but express low levels of CD39 and CD73. Inhibitors of ectonucleotidase activity (e.g. ARL67156) and antagonists of the A(2a) receptor (e.g. ZM241385) blocked Treg-mediated immunosuppression. The inhibition of ADA activity on effector T cells enhanced Treg-mediated immunosuppression. Thus, human nTreg characterized by the presence of CD39 and the low expression of CD26/ADA are responsible for the generation of adenosine, which plays a major role in Treg-mediated immunosuppression. The data suggest that the adenosinergic pathway represents a potential therapeutic target for regulation of immunosuppression in a broad variety of human diseases.

Increased ectonucleotidase expression and activity in regulatory T cells of patients with head and neck cancer

PURPOSE

Regulatory T cell (Treg) frequency and activity are increased in cancer patients and play a major role in tumor escape. Although disease progression is favored by the presence of Treg, mechanisms used by Treg to suppress antitumor immunity are unknown. The ectonucleotidases CD39 and CD73 are expressed in Treg and convert ATP into immunosuppressive adenosine. In this study, the involvement of the adenosinergic pathway in Treg-mediated suppression in head and neck squamous cell carcinoma (HNSCC) patients was evaluated.

EXPERIMENTAL DESIGN

HNSCC patients with an active disease (n = 19) and patients with no evident disease after therapy (n = 14) were studied. Ectonucleotidase expression on CD4(+) T cells and CD4(+)CD25(high) Treg was evaluated by flow cytometry and compared with normal controls. Ectonucleotidase activity was also compared within these three groups. The data were analyzed for associations of ectonucleotidase expression/function with disease stage.

RESULTS

The percentages and expression levels of CD39 and CD73 in CD4(+) T cells and Treg were greater in HNSCC than in normal controls and highest in patients with no evident disease. Patients' Treg hydrolyzed ATP at higher rates and produced higher levels of adenosine than normal controls' Treg. The increased frequency and enzymatic activity of CD4(+)CD39(+) cells corresponded to increased adenosine-mediated suppression of effector T cells, which was partly inhibited by ARL67156, an ectonucleotidase inhibitor, and by ZM241385, a selective A(2a)/A(2b) receptor antagonist.

CONCLUSIONS

CD39(+) Treg frequency and adenosine-mediated suppression are significantly increased in HNSCC patients. The adenosinergic pathway is involved in Treg-mediated immunosuppression in cancer and its attenuation could be a promising immunotherapeutic strategy for patients with HNSCC.

Differential responses of human regulatory T cells (Treg) and effector T cells to rapamycin

Background

The immunosuppressive drug rapamycin (RAPA) promotes the expansion of CD4⁺ CD25^highFoxp3⁺ regulatory T cells via mechanisms that remain unknown. Here, we studied expansion, IL-2R-γ chain signaling, survival pathways and resistance to apoptosis in human Treg responding to RAPA.

Methodology/Principal Findings

CD4⁺CD25⁺ and CD4⁺CD25^neg T cells were isolated from PBMC of normal controls (n = 21) using AutoMACS. These T cell subsets were cultured in the presence of anti-CD3/CD28 antibodies and 1000 IU/mL IL-2 for 3 to 6 weeks. RAPA (1–100 nM) was added to half of the cultures. After harvest, the cell phenotype, signaling via the PI3K/mTOR and STAT pathways, expression of survival proteins and Annexin V binding were determined and compared to values obtained with freshly-separated CD4⁺CD25^high and CD4⁺CD25^neg T cells. Suppressor function was tested in co-cultures with autologous CFSE-labeled CD4⁺CD25^neg or CD8⁺CD25^neg T-cell responders. The frequency and suppressor activity of Treg were increased after culture of CD4⁺CD25⁺ T cells in the presence of 1–100 nM RAPA (p<0.001). RAPA-expanded Treg were largely CD4⁺CD25^highFoxp3⁺ cells and were resistant to apoptosis, while CD4⁺CD25^neg T cells were sensitive. Only Treg upregulated anti-apoptotic and down-regulated pro-apoptotic proteins. Treg expressed higher levels of the PTEN protein than CD4⁺CD25^neg cells. Activated Treg±RAPA preferentially phosphorylated STAT5 and STAT3 and did not utilize the PI3K/mTOR pathway.

Conclusions/Significance

RAPA favors Treg expansion and survival by differentially regulating signaling, proliferation and sensitivity to apoptosis of human effector T cells and Treg after TCR/IL-2 activation.

Expression and signaling of Toll-like receptor 4 (TLR4) and MyD88 in ovarian carcinoma cells

e16508

Background: TLR4, expressed by the cells of the immune system play a role in the protection of the host against pathogens. TLRs are also expressed on human cancer cells, but their role in tumor growth is unknown. The aim of this study was to correlate the presence of TLR4 and MyD88 expression with clinicopathologic outcome in patients with ovarian cancer and to analyze the consequences of signaling via the TLR4/MyD88 pathway in ovarian cancer cell lines. Methods: Tumor specimens from 41 patients with ovarian carcinoma were evaluated for TLR4 and MyD88 by immunohistochemistry and correlated with clinical and pathologic disease features. TLR4/MyD88 expression in OVCAR3, SKOV3, and A2780 was determined using RT-PCR, WB, and immunohistochemistry. NF-kB translocation to nucleus was measured by confocal microscopy. Culture supernatants were tested for levels of cytokines in Luminex-based assays. Proliferation of cancer cells was measured in the CFSE assays. Their sensitivity to paclitaxel (PLX) was measured by Annexin V binding. Western Blot analysis was used to measure activation of the PI3K/Akt, IRAK 1, IRAK 4, and TRIF. Results: In ovarian cancer patients TLR4 and MyD88 expression by the tumor was observed in 100% and 83% of tissues, respectively. The expression of MyD88 was associated with shorter progression-free survival (42 vs 31 months, p < 0.05). Ex vivo studies showed that TLR4 was expressed on OVCAR3, SKOV3, and A2780 cell lines, while A2780 did not expressed MyD88. In MyD88+ tumor cells, LPS increased proliferation (PI 17 vs 8, p < 0.05), activated NF-kB pathway and promoted cytokine production (IL-8, IL-6, RANTES, VEGF and MCP-1). LPS and PLX binding to TLR4 on MyD88+ cells induced activation of PI3K/Akt, IRAK4, and IRAK1, but decreased expression of pro-apoptotic TRIF. In contrast, in MyD88(-) cells LPS did not induce proliferation and neither LPS nor PLX induced secretion of pro-inflammatory cytokines. Further, no changes were noted in IRAK1 expression, but strong signal was observed for TRIF. TLR4+/MyD88+ tumor cells showed grater resistance to PLX. Conclusions: Our ex vivo studies elucidate the molecular mechanisms involved in TLR4/MyD88 signaling. Ligation via TLR4 leads to tumor growth, release of proinflammatory cytokines and induction of resistance to PLX-induced apoptosis.

No significant financial relationships to disclose.

Isolation of functional human regulatory T cells (Treg) from the peripheral blood based on the CD39 expression

Human regulatory T cells (Treg) have been variously defined as CD4(+)CD25(+), CD4(+)CD25(high) or CD4(+)CD25(high)FOXP3(+) cells which are responsible for maintaining peripheral tolerance. Their isolation from human peripheral blood or tissues depends on the expression level of CD25(IL-2Ralpha) - a surface marker which is also expressed on activated effector helper T cells. CD39, a cell surface associated ectonucleotidase, can be used to purify Treg with strong suppressor functions. The CD4(+)CD39(+) T cells catalyze cleavage of adenosine triphosphate (ATP) to adenosine monophosphate (AMP), which is then further cleaved to adenosine. CD4(+)CD39(+) T cells largely overlap with CD4(+)CD25(high)FOXP3(+) but not CD4(+)CD25(+) T cell subset, and mediate equally potent immune suppression. Thus, CD39 surface marker can be successfully used for routine isolation of functionally-active human Treg from the peripheral blood of healthy donors or patients with cancer for studies of their role in health and disease.

Increased frequency and suppression by regulatory T cells in patients with acute myelogenous leukemia

PURPOSE

Regulatory CD4(+)CD25(high)Foxp3(+) T cells (Treg) control peripheral immune tolerance. Patients with cancer, including those with hematologic malignancies, have elevated numbers of Treg in the peripheral circulation and in tumor tissues. However, mechanisms of suppression and clinical significance of Treg, especially in patients with acute myelogenous leukemia (AML), has not been well defined.

EXPERIMENTAL DESIGN

We prospectively evaluated the phenotype, function, and mechanisms of suppression used by Treg in newly diagnosed untreated AML patients. The relationship between the frequency of circulating Treg and the disease status as well as treatment outcome was also evaluated.

RESULTS

The percentage of circulating Treg was higher (P < 0.0001) and their phenotype was distinct in AML patients relative to normal controls. Suppression mediated by Treg coincubated with proliferating autologous responder cells was also higher (P < 0.001) in AML than that mediated by control Treg. Using Transwell inserts, we showed that interleukin-10 and transforming growth factor-beta1 production as well as cell-to-cell contact were necessary for Treg-mediated suppression. Also, the pretreatment Treg frequency predicted response to chemotherapy. Unexpectedly, patients who achieved complete remission still had elevated frequency of Treg, which mediated high levels of suppressor activity.

CONCLUSIONS

Treg accumulating in the peripheral circulation of AML patients mediate vigorous suppression via contact-dependent and contact-independent mechanisms. Patients with lower Treg frequency at diagnosis have a better response to induction chemotherapy. During the post-induction period, the Treg frequency and suppressive activity remain elevated in complete remission, suggesting that Treg are resistant to conventional chemotherapy.