Feasibility and optimization of19F MRI on a clinical 3T with a large field-of-view torso coil

PURPOSE

The purpose of this work is to: 1) demonstrate fluorine-19 (19F) MRI on a 3T clinical system with a large field-of-view (FOV) multi-channel torso coil 2) demonstrate an example parameter selection optimization for a 19F agent to maximize the SNR-efficiency for SPGR, bSSFP, and phase-cycled bSSFP (bSSFP-C), and 3) validate detection feasibility in ex vivo tissues. Methods: Measurements were conducted on a 3.0T Discovery MR750w MRI (GE Healthcare, USA) with an 8-channel 1H/19F torso coil (MRI Tools, Germany). Numerical simulations were conducted for perfluoropolyether (PFPE) to determine the theoretical parameters to maximize SNR-efficiency for the sequences. Theoretical parameters were experimentally verified, and the sensitivity of the sequences was compared with a 10-minute acquisition time with a 3.125x3.125x3mm3 in-plane resolution. Feasibility of a bSSFP-C was also demonstrated in phantom and ex vivo tissues. Results: Flip angles (FA) of 12 and 64 degrees maximized the signal for SPGR and bSSFP, and validation of optimal FA and receiver bandwidth showed close agreement with numerical simulations. Sensitivities of 2.47, 5.81, and 4.44 ms^(-0.5) mM^(-1) and empirical detection limits of 20.3, 1.5, and 6.2 mM were achieved for SPGR, bSSFP, and bSSFP-C, respectively. bSSFP and bSSFP-C achieved 1.8-fold greater sensitivity over SPGR (p<0.01). Conclusion: bSSFP-C was able to improve sensitivity relative to simple SPGR and reduce both bSSFP banding effects and imaging time. The sequence was used to demonstrate the feasibility of 19F MRI at clinical FOVs and field strengths within ex-vivo tissues.

CD155 blockade enhances allogeneic natural killer cell-mediated antitumor response against osteosarcoma

Background

Osteosarcoma (OS) patients that present with metastatic disease have a poor prognosis and no curative options. Allogeneic bone marrow transplant (alloBMT) is curative for hematologic malignancies through the graft-versus-tumor (GVT) effect, but to date has been ineffective for solid tumors like OS. CD155 is expressed on OS and interacts strongly with the inhibitory receptors TIGIT and CD96 but also binds to the activating receptor DNAM-1 on natural killer (NK) cells but has never been targeted after alloBMT. Combining adoptive transfer of allogeneic NK (alloNK) cells with CD155 checkpoint blockade after alloBMT may enhance a GVT effect against OS but could enhance toxicities like graft-versus-host-disease (GVHD).

Methods

Ex vivo activated and expanded murine NK cells were generated with soluble IL-15/IL- 15Rα. AlloNK and syngeneic NK (synNK) cell phenotype, cytotoxicity, cytokine production, and degranulation against the CD155-expressing murine OS cell line K7M2 were assessed in vitro. Mice bearing pulmonary OS metastases underwent alloBMT followed by infusion of alloNK cells with combinations of anti-CD155 and anti-DNAM-1 blockade. Tumor growth, GVHD and survival were monitored and differential gene expression of lung tissue was assessed by RNA microarray.

Results

AlloNK cells exhibited superior cytotoxicity against CD155-expressing OS compared to synNK cells, and this activity was further enhanced by CD155 blockade. CD155 blockade increased alloNK cell degranulation and interferon gamma production through DNAM-1, as these functions were abrogated during DNAM-1 blockade. In vivo, CD155 blockade after alloBMT increased EFS with no exacerbation of GVHD. Treatment with combination CD155 and DNAM-1 blockade ameliorated survival and tumor control benefits seen with CD155 blockade alone. In mice treated with CD155 blockade, genes related to NK cell cytotoxicity were upregulated. DNAM-1 blockade resulted in upregulation of NK cell inhibition.

Conclusions

These results demonstrate the safety and efficacy of infusing alloNK cells with CD155 blockade to mount a GVT effect against OS and show benefits are in part through DNAM-1. Defining the hierarchy of receptors that govern alloNK responses will be critical to translating combination adoptive NK cell and immune checkpoint inhibition for patients with solid tumors treated with alloBMT.

WHAT IS ALREADY KNOWN ON THIS TOPIC

Allogeneic bone marrow transplant (alloBMT) has yet to show efficacy in treating solid tumors, such as osteosarcoma (OS). CD155 is expressed on OS and interacts with natural killer (NK) cell receptors, such as activating receptor DNAM-1 and inhibitory receptors TIGIT and CD96 and has a dominant inhibitory effect on NK cell activity. Targeting CD155 interactions on allogeneic NK cells could enhance anti-OS responses, but this has not been tested after alloBMT.

WHAT THIS STUDY ADDS

CD155 blockade enhances allogeneic natural killer cell-mediated cytotoxicity against osteosarcoma and improved event-free survival after alloBMT in an in vivo mouse model of metastatic pulmonary OS. Addition of DNAM-1 blockade abrogated CD155 blockade-enhanced allogeneic NK cell antitumor responses.

HOW THIS STUDY MIGHT AFFECT RESEARCH PRACTICE OR POLICY

These results demonstrate efficacy of allogeneic NK cells combined with CD155 blockade to mount an antitumor response against CD155-expressing OS. Translation of combination adoptive NK cell and CD155 axis modulation offers a platform for alloBMT treatment approaches for pediatric patients with relapsed and refractory solid tumors.

Combining Immunocytokine and Ex Vivo Activated NK Cells as a Platform for Enhancing Graft-Versus-Tumor Effects Against GD2+ Murine Neuroblastoma

Management for high-risk neuroblastoma (NBL) has included autologous hematopoietic stem cell transplant (HSCT) and anti-GD2 immunotherapy, but survival remains around 50%. The aim of this study was to determine if allogeneic HSCT could serve as a platform for inducing a graft-versus-tumor (GVT) effect against NBL with combination immunocytokine and NK cells in a murine model. Lethally irradiated C57BL/6 (B6) x A/J recipients were transplanted with B6 bone marrow on Day +0. On day +10, allogeneic HSCT recipients were challenged with NXS2, a GD2+ NBL. On days +14-16, mice were treated with the anti-GD2 immunocytokine hu14.18-IL2. In select groups, hu14.18-IL2 was combined with infusions of B6 NK cells activated with IL-15/IL-15Rα and CD137L ex vivo. Allogeneic HSCT alone was insufficient to control NXS2 tumor growth, but the addition of hu14.18-IL2 controlled tumor growth and improved survival. Adoptive transfer of ex vivo CD137L/IL-15/IL-15Rα activated NK cells with or without hu14.18-IL2 exacerbated lethality. CD137L/IL-15/IL-15Rα activated NK cells showed enhanced cytotoxicity and produced high levels of TNF-α in vitro, but induced cytokine release syndrome (CRS) in vivo. Infusing Perforin-/- CD137L/IL-15/IL-15Rα activated NK cells had no impact on GVT, whereas TNF-α-/- CD137L/IL-15/IL-15Rα activated NK cells improved GVT by decreasing peripheral effector cell subsets while preserving tumor-infiltrating lymphocytes. Depletion of Ly49H+ NK cells also improved GVT. Using allogeneic HSCT for NBL is a viable platform for immunocytokines and ex vivo activated NK cell infusions, but must be balanced with induction of CRS. Regulation of TNFα or activating NK subsets may be needed to improve GVT effects.

Approaches to Enhance Natural Killer Cell-Based Immunotherapy for Pediatric Solid Tumors

Treatment of metastatic pediatric solid tumors remain a significant challenge, particularly in relapsed and refractory settings. Standard treatment has included surgical resection, radiation, chemotherapy, and, in the case of neuroblastoma, immunotherapy. Despite such intensive therapy, cancer recurrence is common, and most tumors become refractory to prior therapy, leaving patients with few conventional treatment options. Natural killer (NK) cells are non-major histocompatibility complex (MHC)-restricted lymphocytes that boast several complex killing mechanisms but at an added advantage of not causing graft-versus-host disease, making use of allogeneic NK cells a potential therapeutic option. On top of their killing capacity, NK cells also produce several cytokines and growth factors that act as key regulators of the adaptive immune system, positioning themselves as ideal effector cells for stimulating heavily pretreated immune systems. Despite this promise, clinical efficacy of adoptive NK cell therapy to date has been inconsistent, prompting a detailed understanding of the biological pathways within NK cells that can be leveraged to develop "next generation" NK cell therapies. Here, we review advances in current approaches to optimizing the NK cell antitumor response including combination with other immunotherapies, cytokines, checkpoint inhibition, and engineering NK cells with chimeric antigen receptors (CARs) for the treatment of pediatric solid tumors.

CXCR4 allows T cell acute lymphoblastic leukemia to escape from JAK1/2 and BCL2 inhibition through CNS infiltration

Targeting the JAK/STAT and BCL2 pathways in patients with relapsed/refractory T cell acute lymphoblastic leukemia (T-ALL) may provide an alternative approach to achieve clinical remissions. Ruxolitinib and venetoclax show a dose-dependent effect on T-ALL individually, but combination treatment reduces survival and proliferation of T-ALL in vitro. Using a xenograft model, the combination treatment fails to improve survival, with death from hind limb paralysis. Despite on-target inhibition by the drugs, histopathology demonstrates increased leukemic infiltration into the central nervous system (CNS) as compared to liver or bone marrow. Liquid chromatography-tandem mass spectroscopy shows that ruxolitinib and venetoclax insufficiently cross into the CNS. The addition of the CXCR4 inhibitor plerixafor with ruxolitinib and venetoclax reduces clinical scores and enhances survival. While combination therapy with ruxolitinib and venetoclax shows promise for treating T-ALL, additional inhibition of the CXCR4-CXCL12 axis may be needed to maximize the possibility of complete remission.

Programmed cell death protein 1 on natural killer cells: fact or fiction?

Programmed cell death protein 1 (PD-1) has become one of the most investigated targets for cancer immunotherapy. Most research has centered on inhibiting PD-1 on T cells, but there is increased interest in understanding the role of PD-1 on NK cells. While the expression of PD-1 on NK cells has been controversial, with papers publishing contradictory results in multiple models, there is increased clinical interest in NK and PD-1 immunotherapy. In this issue of the JCI, Judge et al. comprehensively explore the lack of PD-1 expression on murine, canine, and human NK cells and the clinical implication of these findings.

Surgical resection of solitary adrenal metastasis from esophageal carcinoma following esophagectomy

The prognosis of esophageal carcinoma following esophagectomy is poor due to a high frequency of metastasis to periesophageal lymph nodes and distant organs. However, we experienced a case with good prognosis following resection of a solitary adrenal metastatic tumor. The patient was a 70-year-old man diagnosed with type 2 esophageal cancer (Lt-Ae, T2N1M0, Stage IIB) who was treated with esophagectomy. Eight months following surgery, solitary adrenal metastasis was detected by CT, and was resected. At 42 months follow-up he has had a good quality of life in the community without evidence of recurrence. To the best of our knowledge, only five cases with resected solitary adrenal metastases including our case, have been reported, and show a greater than 1-year survival. Consequently, we suggest that resection of solitary organ metastases is a good alternative, even following esophagectomy.

Tumor stroma as the main source of inhibin production in ovarian epithelial tumors

PROBLEM

Elevated serum inhibin levels have been found in ovarian cancer patients; however, the source of the elevated inhibin is uncertain. Previous studies of activin in human ovarian cancer suggest that activin may promote the growth of the tumor. The aims of this study were to examine the source of elevated inhibin from ovarian epithelial tumors (OETs) and to preliminarily investigate the role of the gonadotropin-inhibin/activin relationship in the development of OET.

METHOD OF STUDY

The protein and mRNA expression of alpha and betaA subunits of inhibin/activin were examined by immunohistochemistry (IHC) and reverse transcription polymerase chain reaction (RT-PCR) in 120 OETs, including 30 benign cystadenomas, 30 borderline tumors, and 60 carcinomas. Stromal and epithelial cells were microdissected from 23 OETs to further examine the expression of alpha and betaA subunits by RT-PCR. Dimeric inhibin A and activin A production were measured by using the two-site ELISA from three OET cell lines in culture under treatment of follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

RESULTS

betaA subunit was expressed in the epithelial component of 100% of the cystadenomas, in 80% of borderline tumors, and in 75% of the carcinomas, but not in tumor stroma. Inhibin alpha expression was not found in the epithelium of all OETs studied, but focal inhibin alpha immunoreactivity was seen in the tumor stroma (mainly luteinized stromal cells) in the majority of cases. Dimeric activin A was produced by all of the three OET cell lines with a 1.5-1.9-fold increment after FSH stimulation. However, activin A production was not augmented by LH treatment. No inhibin A was produced by the three OET cell lines with or without gonadotropin stimulation.

CONCLUSIONS

The stroma of OET is the major source in the production of inhibin alpha (monomer). Dimeric inhibin A production may be the result of combined efforts of the tumor stroma (alpha subunit) and epithelium (betaA subunit). Cellular, compartmental expression of inhibin and activin subunits may play a role in the development of OET, although the mechanism remains undefined. The unopposed activin A production stimulated by FSH in OET cell lines suggests that activin production may represent one of the cellular mechanisms of growth promotion by FSH.

The effects of oxytocin and vasopressin on partner preferences in male and female prairie voles (Microtus ochrogaster)

This study compared the effects of centrally administered oxytocin (OT) and arginine vasopressin (AVP) on partner preference formation and social contact in male and female prairie voles (Microtus ochrogaster). After 1 hr of cohabitation and pretreatment with either AVP or OT, both males and females exhibited increased social contact and significant preference for the familiar partner. After pretreatment with either an OT receptor antagonist (OTA) or an AVP (V1a) receptor antagonist (AVPA), neither OT nor AVP induced a partner preference. In addition, treatment with OT+OTA or AVP+AVPA was associated with low levels of social contact in both sexes. Either AVP or OT is sufficient to facilitate social contact if either the OT or AVP receptor is available. However, the formation of partner preferences may require access to both AVP and OT receptors.

The effects of oxytocin and vasopressin on partner preferences in male and female prairie voles (Microtus ochrogaster)

This study compared the effects of centrally administered oxytocin (OT) and arginine vasopressin (AVP) on partner preference formation and social contact in male and female prairie voles (Microtus ochrogaster). After 1 hr of cohabitation and pretreatment with either AVP or OT, both males and females exhibited increased social contact and significant preference for the familiar partner. After pretreatment with either an OT receptor antagonist (OTA) or an AVP (V1a) receptor antagonist (AVPA), neither OT nor AVP induced a partner preference. In addition, treatment with OT+OTA or AVP+AVPA was associated with low levels of social contact in both sexes. Either AVP or OT is sufficient to facilitate social contact if either the OT or AVP receptor is available. However, the formation of partner preferences may require access to both AVP and OT receptors.

Estrogen modulates paracellular permeability of human endothelial cells by eNOS- and iNOS-related mechanisms

Estradiol had a biphasic effect on permeability across cultures of human umbilical vein endothelial cells (HUVEC): at nanomolar concentrations it decreased the HUVEC culture permeability, but at micromolar concentrations it increased the permeability. The objective of the present study was to test the hypothesis that the changes in permeability were mediated by nitric oxide (NO)-related mechanisms. The results revealed dual modulation of endothelial paracellular permeability by estrogen. 1) An endothelial NO synthase (eNOS)-, NO-, and cGMP-related, Ca2+-dependent decrease in permeability was activated by nanomolar concentrations of estradiol, resulting in enhanced Cl- influx, increased cell size, and increases in the resistance of the lateral intercellular space (RLIS) and in the resistance of the tight junctions (RTJ); these effects appeared to be limited by the ability of cells to generate cGMP in response to NO. 2) An inducible NO synthase (iNOS)- and NO-related, Ca2+-independent increase in permeability was activated by micromolar concentrations of estradiol, resulting in enhanced Cl- efflux, decreased cell size, and decreased RLIS and RTJ. We conclude that the net effect on transendothelial permeability across HUVEC depends on the relative contributions of each of these two systems to the total paracellular resistance.

Effects of estrogen on tight junctional resistance in cultured human umbilical vein endothelial cells

OBJECTIVE

To study the effects of estrogen on transendothelial paracellular permeability in women.

METHODS

Human umbilical vein endothelial cells (HUVEC) obtained from women were grown on filters. The paracellular permeability characteristics were determined in terms of changes in the permeability to the polar acid pyranine (Ppyr) and as changes in the transendothelial electrical resistance (RTE). Tight junctional resistance characteristics were assayed by lowering luminal NaCl and measuring the dilution potential, and were expressed as the ratio of monoion mobility uCl/uNa (cation selectivity).

RESULTS

Low extracellular calcium and hyperosmolarity increased Ppyr and decreased RTE. The former but not the latter condition abolished the endothelium-specific cation selectivity. Treatment with 10 nM of estradiol-17 beta had no effect on RTE, but it increased the cation selectivity. The effect of estradiol required 1-6 hours' incubation with the hormone; it was dose dependent and saturable, with a median effective concentration of estradiol of 1 nM. Diethylstilbestrol, but not estriol, could mimic the effect of estradiol, and the estrogen receptor antagonist ICI-182, 780 blocked it.

CONCLUSION

Cultured HUVEC cells form patent tight junctions. Estrogens increase the cation selectivity across HUVEC cultures. The effect of estrogen may be mediated by an estrogen receptor. These effects may be important for vasculoprotection in cases of sudden changes in ions levels across the capillary wall, such as ischemia or reperfusion.

In vitro cytokine modulation of intercellular adhesion molecule-1 expression on systemic sclerosis dermal fibroblasts

Our objective was to study the regulation of intercellular adhesion molecule-1 (ICAM-1) expression by cytokines on cultured fibroblasts obtained from systemic sclerosis and normal skin. ICAM-1 expression on dermal fibroblasts obtained from diffuse systemic sclerosis patients with early disease (< or = 2 years) and normal dermal fibroblasts incubated with and without cytokines was measured by radioimmunoassay and flow cytometry. Systemic sclerosis dermal fibroblasts expressed lower basal levels of ICAM-1 than did normal dermal fibroblasts. Both the normal and systemic sclerosis dermal fibroblasts increased their cell surface expression of ICAM-1 in response to interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma) in a dose-dependent fashion. Systemic sclerosis dermal fibroblasts appeared to be hyperresponsive to IL-1 beta, TNF-alpha, and IFN-gamma. ICAM-1 expression in response to cytokine stimulation increased to a greater degree on systemic sclerosis compared to normal dermal fibroblasts. The enhanced ICAM-1 expression may play a role in the retention of leukocytes involved in systemic sclerosis skin lesions.

Serum LH levels in the differential diagnosis of hirsute anovulatory women

Polycystic ovarian syndrome (PCO) occurs frequently in hirsute patients. A dissociated explosive response of LH to LHRH administration has been associated with the diagnosis of PCO. Twenty-four of 58 women seen because of hirsutism were found to have ovarian dysfunction based on clinical signs such as anovulation and irregular menstrual cycles. Plasma androgen levels were elevated in the patient group. The LHRH test (200 micrograms, iv) was applied to the 24 patients and compared with 13 normal ovulatory controls. Serum FSH levels before and after the LHRH test were normal in all patients. Two patterns of LH response to LHRH stimulation were observed: an explosive response in 17 patients (delta LH: 39.4 +/- 21.8 IU/l, control group: 7.35 +/- 4.4 IU/l, P < 0.01) and a normal response in 7 patients (delta LH: 7.53 +/- 2.41 IU/l). There was a significant correlation (r = 0.63, P < 0.05) between basal LH levels and LH response to LHRH. Sensitivity and specificity calculated for basal LH levels higher than 6.0 IU/l, considering the LHRH test as reference, were 58% and 85%, respectively. The positive predictive value measuring the possibility of LH higher than 6.0 IU/l to be from a patient with PCO (explosive response to LHRH) was 92%. These data suggest that, in hirsute anovulatory patients, basal LH levels may be a good predictor in the diagnosis of polycystic ovarian syndrome.

In situ expression of cytokines and cellular adhesion molecules in the skin of patients with systemic sclerosis. Their role in early and late disease

Cytokines and cellular adhesion molecules (CAMs) may play a role in the inflammatory and fibrotic processes underlying systemic sclerosis (SSc). We compared the immunohistological distribution of cytokines and CAMs in skin biopsies from 12 SSc patients and 14 normal (NL) individuals. Among CAMs, vascular cell adhesion molecule-1 (VCAM-1), which mediates leukocyte-endothelial adhesion, showed increased expression on SSc versus NL endothelium and stratum granulosum. P-selectin was up-regulated in SSc versus NL stratum granulosum. The CD44 lymphocyte homing receptor showed the most striking differences between SSc and NL: its expression was increased in SSc stratum granulosum, stratum spinosum, on lymphocytes, and macrophages. Regarding cytokines, interleukin-6 (IL-6) expression was increased on SSc versus NL endothelium and fibroblasts. Tumor necrosis factor-alpha (TNF-alpha) reactivity was more prevalent in SSc than NL stratum granulosum, whereas IL-8 expression was higher on SSc compared to NL endothelium. Some CAMs, such as VCAM-1 and P-selectin, and cytokines, namely TNF-alpha and IL-8, were more commonly found in skin biopsies taken from early (< or = 1 year's duration) SSc, while others, such as IL-6, showed up-regulation in the late stage of the disease. The results suggest that certain CAMs and cytokines may play a differential role in both the early, inflammatory, and the late, fibrotic stage of SSc.

The ontogeny of pulmonary defenses: alveolar macrophage function in neonatal and juvenile rhesus monkeys

Using the technique of bronchoalveolar lavage, we isolated alveolar macrophages (AM) from the lower respiratory tract of newborn (1-4 days of age), infant (6-10 days of age), juvenile (3-6 months of age), and adult rhesus monkeys. The AM thus obtained were assayed in vitro to determine their chemotactic, phagocytic, and candidicidal capabilities. The predominant (greater than or equal to 89%) cell type in bronchoalveolar lavage effluent in all ages was the AM. Chemotaxis, phagocytosis, and killing of Candida albicans were markedly impaired in neonatal AM as compared with those from infants, juveniles, and adults. AM chemotactic activity achieved normal adult values by 6 days of age. Phagocytosis, and to a lesser extent candidicidal activity, were significantly improved in 6-day-old animals, but adult levels were still not achieved even by 6 months of age.

Comparison of human growth hormone levels in children with satisfactory and unsatisfactory growth

Sixty-six children with satisfactory growth and 73 with unsatisfactory growth (both sexes) from three different age groups (1 year, 5 years and 10 years) were included in this study. It was observed that the serum concentrations of human growth hormone (hGH) in children with satisfactory growth ranged from 1.00 to 4.00 ng/ml and never exceeded 4.00 ng/ml. In a comparative study there was a significant increase in serum hGH levels in subjects of all age groups who were not growing satisfactorily. Twelve children between 12 and 13 months of age with unsatisfactory growth were nutritionally rehabilitated for 4 months and the changes in weight and serum hGH levels were assessed monthly. The results indicated a definite fall of hGH level after rehabilitation and reached the normal level 3 months after rehabilitation. Moreover, an inverse relationship between body weight and serum hGH level was observed.

Variability of daily creatinine excretion in healthy adults

In order to determine the within-subject variability of creatinine excretion, the 24-h output was measured over 5 consecutive d in 12 subjects. The mean within-subject coefficient of variation was 3.6 per cent. There was much greater variation between subjects. The creatinine excretion in g/d was 30-40 per cent lower in Burmese subjects than in Europeans and North Americans, but the excretion per kg was slightly higher, suggesting that the Burmese are more muscular.