Fluorescence tracking demonstrates T cell recirculation is transiently impaired by radiation therapy to the tumor

T cells recirculate through tissues and lymphatic organs to scan for their cognate antigen. Radiation therapy provides site-specific cytotoxicity to kill cancer cells but also has the potential to eliminate the tumor-specific T cells in field. To dynamically study the effect of radiation on CD8 T cell recirculation, we used the Kaede mouse model to photoconvert tumor-infiltrating cells and monitor their movement out of the field of radiation. We demonstrate that radiation results in loss of CD8 T cell recirculation from the tumor to the lymph node and to distant sites. Using scRNASeq, we see decreased proliferating CD8 T cells in the tumor following radiation therapy resulting in a proportional enrichment in exhausted phenotypes. By contrast, 5 days following radiation increased recirculation of T cells from the tumor to the tumor draining lymph node corresponds with increased immunosurveillance of the treated tumor. These data demonstrate that tumor radiation therapy transiently impairs systemic T cell recirculation from the treatment site to the draining lymph node and distant untreated tumors. This may inform timing therapies to improve systemic T cell-mediated tumor immunity.

Tumor resident memory CD8 T cells and concomitant tumor immunity develop independently of CD4 help

Tissue resident memory (Trm) CD8 T cells infiltrating tumors represent an enriched population of tumor antigen-specific T cells, and their presence is associated with improved outcomes in patients. Using genetically engineered mouse pancreatic tumor models we demonstrate that tumor implantation generates a Trm niche that is dependent on direct antigen presentation by cancer cells. However, we observe that initial CCR7-mediated localization of CD8 T cells to tumor draining lymph nodes is required to subsequently generate CD103+ CD8 T cells in tumors. We observe that the formation of CD103+ CD8 T cells in tumors is dependent on CD40L but independent of CD4 T cells, and using mixed chimeras we show that CD8 T cells can provide their own CD40L to permit CD103+ CD8 T cell differentiation. Finally, we show that CD40L is required to provide systemic protection against secondary tumors. These data suggest that CD103+ CD8 T cell formation in tumors can occur independent of the two-factor authentication provided by CD4 T cells and highlight CD103+ CD8 T cells as a distinct differentiation decision from CD4-dependent central memory.

ICOS is upregulated on T cells following radiation and agonism combined with radiation results in enhanced tumor control

Multiple preclinical studies have shown improved outcomes when radiation therapy is combined with immune modulating antibodies. However, to date, many of these promising results have failed to translate to successful clinical studies. This led us to explore additional checkpoint and co-stimulatory pathways that may be regulated by radiation therapy. Here, we demonstrate that radiation increases the expression of inducible T cell co-stimulator (ICOS) on both CD4 and CD8 T cells in the blood following treatment. Moreover, when we combined a novel ICOS agonist antibody with radiation we observed durable cures across multiple tumor models and mouse strains. Depletion studies revealed that CD8 T cells were ultimately required for treatment efficacy, but CD4 T cells and NK cells also partially contributed to tumor control. Phenotypic analysis showed that the combination therapy diminished the increased infiltration of regulatory T cells into the tumor that typically occurs following radiation alone. Finally, we demonstrate in a poorly immunogenic pancreatic tumor model which is resistant to combined radiation and anti-PD1 checkpoint blockade that the addition of this novel ICOS agonist antibody to the treatment regimen results in tumor control. These findings identify ICOS as part of a T cell pathway that is modulated by radiation and targeting this pathway with a novel ICOS antibody results in durable tumor control in preclinical models.

Tumor resident memory CD8 T cell formation and concomitant tumor immunity is CD40L dependent and CD4 independent

The implantation of cancer cell lines into immunocompetent mice acts as a vaccination event, resulting in T cell immunity that impacts both tumor progression and the response to subsequent therapy. We have previously shown that blocking immunity at tumor implantation using anti-CD40L antibodies blocks development of an intratumoral antigen-specific CD8 T cell population with tissue resident memory (Trm) phenotypes, and also limits responsiveness to radiation therapy and immunotherapy combinations. Using pancreatic tumors derived from Pdx1-Cre and Pdx1-Cre /R26LSL-LSIY mice crossed with KrasLSL-G12D/+Tp53LSL-R172H/+ mice, we explored the role of CD4 T cells in providing CD40-CD40L help to generate Trm and conventional T central memory CD8 T cells (Tcm) cells in the tumor and systemically. Using depleting antibodies, we identified that Trm cells in the tumor could form independently of CD4 T cells but were lost following CD40L blockade. By contrast, systemically circulating Tcm cells that could re-expand after antigen-specific challenge were dependent on both CD4 T cells and CD40-CD40L interactions. Notably, concomitant immunity generated by tumor implantation that can prevent tumor growth on the opposite flank could also occur independently of CD4 T cells, but was lost on CD40L blockade. Systemic vaccination with Listeria monocytogenes expressing SIY efficiently induced the formation of SIY-specific Tcm cells but did not impact tumor implantation. These data suggest that tumor implantation generates Trm cells independently of CD4 T cells, and that these cells, not Tcm cells, sustain concomitant immunity. These data may impact immune therapies designed to control metastatic seeding in patients.

Supported by grants from NIH (R01CA182311,  R01CA244142, R01CA208644).

Fluorescence tagging to monitor CD8 T cell recirculation from the tumor to the tumor-draining lymph node: the impact of focal radiation therapy on recirculation

T cells are continuously moving through tissues and recirculating back into the peripheral blood via lymph nodes. In cancer, tumor-specific T cells are enriched in the tumor environment and their presence is associated with improved outcome in patients and in preclinical models. T cells are known to contribute to tumor control following radiotherapy despite evidence indicating that radiation can be directly cytotoxic to lymphocytes. The impact of radiation therapy on recirculation of T cells through the tumor to the tumor draining lymph node (TDLN) and their trafficking to distant sites is unclear. By photoconverting tumor infiltrating cells using focal UV in Kaede mice we can use fluorescence tagging to directly identify T cells in the TDLN that originated in the tumor. We demonstrate that radiation therapy significantly decreases CD8 T cell trafficking from the tumor to the TDLN. Using single cell RNASeq and flow cytometry, we demonstrate that radiation therapy is locally cytotoxic to proliferating effector CD8 T cells within the tumor environment. This results in the loss of this effector population in the TDLN following treatment. Using flow cytometry and direct blockade of T cell entry into the LN, we characterize the CD8 T cells in the TDLN that proliferate following radiation therapy. Our data demonstrate that radiation therapy is locally cytotoxic and restricts CD8 T cell recirculation to the TDLN. Since tumor control following radiation therapy is partially dependent on CD8 T cell responses, these data force us to re-evaluate both the type and location of T cell populations that contribute to tumor control following radiation therapy.

Supported by grants from the NIH (R01CA182311, R01CA244142, R01CA208644)

Program Report: Nîsohkamâtowak-Helping Patients and Families Living With Kidney Disease in Northern Saskatchewan

Purpose of the Program:

Nîsohkamâtowak, the Cree word for Helping Each Other, is an initiative to close gaps in kidney health care for First Nations and Métis patients, their families, and communities in northern Saskatchewan. Nîsohkamâtowak emerged from a collaboration between the Kidney Health Community Program and First Nations and Métis Health Services to find ways to deliver better care and education to First Nations and Métis people living with kidney disease while acknowledging Truth and Reconciliation and the Calls to Action.

Sources of Information:

This article describes how traditional Indigenous protocols and storytelling were woven into the Nîsohkamâtowak events, gathering of patient and family voices in writing and video format, and how this work led to a collaborative co-designed process that incorporates the Truth and Reconciliation: Calls to Action into kidney care and the benefits we have seen so far. The teachings of the 4 Rs—respect, reciprocity, responsibility, and relevance, were critical to ensuring that Nîsohkamâtowak reports and learning were shared with participants and the communities represented in this initiative.

Methods:

Group discussions and sharing circles were facilitated in several locations throughout northern and central Saskatchewan. Main topics of discussion were traditional medicines, residential schools impact, community and peer supports for kidney disease patients, and cultural safety education for health care providers.

Key Findings:

The general themes selected for improvement were education, support within the local community, traditional practices and cultural competency, and delivery of services. To address these gaps in kidney care, the following objectives were co-created with First Nations and Métis patients, families, and communities for Kidney Health to provide culturally appropriate education and resources, to ensure appropriate follow-up support to include strengthening connections to communities and other health authorities, to incorporate traditional practices into program design, and to ensure appropriate service delivery across the spectrum of care with a focus on screening and referral, which is strongly linked to coordination of care with local health centers.

Implications:

As a result of this work, the Kidney Health Community Program restructured the delivery of services and continues to work with Nîsohkamâtowak advisors on safety initiatives and chronic kidney disease awareness, prevention, and management in their respective communities. The Truth and Reconciliation and Calls to Action are honored to close the gaps in kidney care.

Limitations:

Nîsohkamâtowak is a local Kidney Health initiative that has the good fortune of having dedicated funding and staff to carry out this work. The findings may be unique to the First Nations and Métis communities and people who shared their stories. Truth and Reconciliation is an ongoing commitment that must be nurtured. Although not part of this publication, the effects of COVID-19 have made it difficult to further advance the Calls to Action, with more limited staff resources and the inability to meet in person as in the past.

TGFβ suppresses CD8+ T cell expression of CXCR3 and tumor trafficking

Transforming growth factor beta (TGFβ) is a multipotent immunosuppressive cytokine. TGFβ excludes immune cells from tumors, and TGFβ inhibition improves the efficacy of cytotoxic and immune therapies. Using preclinical colorectal cancer models in cell type-conditional TGFβ receptor I (ALK5) knockout mice, we interrogate this mechanism. Tumor growth delay and radiation response are unchanged in animals with Treg or macrophage-specific ALK5 deletion. However, CD8αCre-ALK5flox/flox (ALK5ΔCD8) mice reject tumors in high proportions, dependent on CD8+ T cells. ALK5ΔCD8 mice have more tumor-infiltrating effector CD8+ T cells, with more cytotoxic capacity. ALK5-deficient CD8+ T cells exhibit increased CXCR3 expression and enhanced migration towards CXCL10. TGFβ reduces CXCR3 expression, and increases binding of Smad2 to the CXCR3 promoter. In vivo CXCR3 blockade partially abrogates the survival advantage of an ALK5ΔCD8 host. These data demonstrate a mechanism of TGFβ immunosuppression through inhibition of CXCR3 in CD8+ T cells, thereby limiting their trafficking into tumors.

Effects of the Temperature and Ethanol on the Kinetics of Proanthocyanidin Adsorption in Model Wine Systems

The kinetics and quantitative and qualitative effects of grape proanthocyanidin (PA) adsorption to grape skin-derived cell wall material (CWM) were investigated in five different temperature-ethanol conditions. Progress curves for each condition were constructed by monitoring the decrease in concentration of PA solutions after exposure to CWM over 720 min. Adsorption isotherms were constructed for each condition, and a Langmuir equation model was applied to each via regression analysis. Compositional changes in the PA solutions after exposure to CWM were determined using phloroglucinolysis and gel permeation chromatography (GPC). A negative correlation between PA adsorption and both the temperature and ethanol concentration was found. Progress curves suggested that both the temperature and ethanol affect the equilibration rate of the adsorption reactions. Additionally, equilibration rates for lower temperature and ethanol concentration conditions were found to be much longer than previously reported, taking up to 720 min. Phloroglucinolysis results showed no discernible correlation between the temperature or ethanol concentration and percent galloylation or percent gallo units of adsorbed compounds. Analyses by phloroglucinolysis and GPC indicate a preferential adsorption of larger molecular weight PAs under all conditions, although no discernible impact on PA composition was detected. Additionally, findings suggest that both the temperature and ethanol concentration impact the percent reduction in molar mass of the PA solution. Data from this study were ultimately utilized to develop a computational model for predicting phenolic extraction during red wine fermentations.

Anti-tumor immunity generated as an artifact of tumor implantation determines the response to immunotherapy in murine models

Cancer cell lines grown in vitro and implanted into mice are a centerpiece of preclinical modeling. However, tumor implantation is an in vivo vaccination event that can impact tumor growth. Checkpoint inhibitors targeting PD1 or CTLA4 interactions are effective at unleashing suppressed pre-existing immunity in murine models, but do not generate new immune responses.

We hypothesized that tumor control by checkpoint inhibitor immunotherapies was dependent on pre-existing immunity generated at tumor implantation.

Using cancer cells engineered to express model antigens, spontaneous tumor models with defined trackable antigens, or unmodified cancer cells, we demonstrate that tumor implantation results in initial T cell mediated immunity. As the tumors progress, these cells become undetectable in the periphery and accumulate in the tumor, but do not prevent tumor progression. While tumors respond to checkpoint inhibitors administered closely following implantation, delayed administration results in a loss of efficacy. This efficacy can be recovered by the addition of radiation therapy to checkpoint inhibitors, permitting cure of established murine tumors that are not controlled by either therapy alone. However, blocking the immune response at tumor implantation using a range of approaches results in a complete loss of efficacy of tumor control by all therapies based around checkpoint inhibitors. We demonstrate an approach to ‘silently’ establish tumors in mice to test therapies that can initiate de novo immunity to tumors.

These data have significant implications for current clinical attempts to use checkpoint inhibitors, which may not be a solution for patients without pre-existing immunity to their tumor.

Pathogenicity of IFN-γ+ Th17 cells is independent of T-bet (P4128)

It is now established that T helper (Th) cell subsets, particularly Th17 cells, are more dynamic than originally anticipated and can acquire the expression of other lineage effector cytokines. However, the molecular cues that dictate their plasticity are unknown. We show that IL-23 plays a central role in the plasticity of Th17 cells and is essential for the generation and propagation of IFN-γ-producing Th17 (IL-17+ IFN-γ+) cells. During the development of experimental autoimmune encephalomyelitis (EAE) IL-17+ IFN-γ+ T cells are preferentially expanded in the central nervous system (CNS). Using an IL-17A-IFN-γ double reporter mouse and I-Ab/MOG38-49 tetramer, we determined that they displayed characteristics of pathogenic T cells, such as GM-CSF expression, and contained the highest number of MOG-specific T cells. Interestingly, the Th1-associated transcription factors T-bet, STAT1 and STAT4 were not involved in the induction of IFN-γ by Th17 cells in vitro. Moreover, in contrast to previous studies showing a role for T-bet in Th1 and Th17-mediated EAE, we demonstrate that T-bet expression in T cells is not required for the emergence of CNS-infiltrating IL-17+ IFN-γ+ T cells and the development of Th17-driven EAE. Our results suggest the existence of different epigenetic programs that regulate IFN-γ expression in Th1 and Th17 cells.

MRI of auto-transplantation of bone marrow-derived stem-progenitor cells for potential repair of injured arteries

Background

This study was to validate the feasibility of using clinical 3.0T MRI to monitor the migration of autotransplanted bone marrow (BM)-derived stem-progenitor cells (SPC) to the injured arteries of near-human sized swine for potential cell-based arterial repair.

Methodology

The study was divided into two phases. For in vitro evaluation, BM cells were extracted from the iliac crests of 13 domestic pigs and then labeled with a T2 contrast agent, Feridex, and/or a fluorescent tissue marker, PKH26. The viability, the proliferation efficiency and the efficacies of Feridex and/or PKH26 labeling were determined. For in vivo validation, the 13 pigs underwent endovascular balloon-mediated intimal damages of the iliofemoral arteries. The labeled or un-labeled BM cells were autotransplanted back to the same pig from which the BM cells were extracted. Approximately three weeks post-cell transplantation, 3.0T T2-weighted MRI was performed to detect Feridex-created signal voids of the transplanted BM cells in the injured iliofemoral arteries, which was confirmed by subsequent histologic correlation.

Principal Findings

Of the in vitro study, the viability of dual-labeled BM cells was 95–98%. The proliferation efficiencies of dual-labeled BM cells were not significantly different compared to those of non-labeled cells. The efficacies of Feridex- and PKH26 labeling were 90% and 100%, respectively. Of the in vivo study, 3.0T MRI detected the auto-transplanted BM cells migrated to the injured arteries, which was confirmed by histologic examinations.

Conclusion

This study demonstrates the capability of using clinical 3.0T MRI to monitor the auto-transplantation of BM cells that migrate to the injured arteries of large animals, which may provide a useful MRI technique to monitor cell-based arterial repair.

Magnetic resonance imaging of bone marrow cell-mediated interleukin-10 gene therapy of atherosclerosis

Background

A characteristic feature of atherosclerosis is its diffuse involvement of arteries across the entire human body. Bone marrow cells (BMC) can be simultaneously transferred with therapeutic genes and magnetic resonance (MR) contrast agents prior to their transplantation. Via systemic transplantation, these dual-transferred BMCs can circulate through the entire body and thus function as vehicles to carry genes/contrast agents to multiple atherosclerosis. This study was to evaluate the feasibility of using in vivo MR imaging (MRI) to monitor BMC-mediated interleukin-10 (IL-10) gene therapy of atherosclerosis.

Methodology

For in vitro confirmation, donor mouse BMCs were transduced by IL-10/lentivirus, and then labeled with a T2-MR contrast agent (Feridex). For in vivo validation, atherosclerotic apoE^−/− mice were intravenously transplanted with IL-10/Feridex-BMCs (Group I, n = 5) and Feridex-BMCs (Group II, n = 5), compared to controls without BMC transplantation (Group III, n = 5). The cell migration to aortic atherosclerotic lesions was monitored in vivo using 3.0T MRI with subsequent histology correlation. To evaluate the therapeutic effect of BMC-mediated IL-10 gene therapy, we statistically compared the normalized wall indexes (NWI) of ascending aortas amongst different mouse groups with various treatments.

Principal Findings

Of in vitro experiments, simultaneous IL-10 transduction and Feridex labeling of BMCs were successfully achieved, with high cell viability and cell labeling efficiency, as well as IL-10 expression efficiency (≥90%). Of in vivo experiments, MRI of animal groups I and II showed signal voids within the aortic walls due to Feridex-created artifacts from the migrated BMCs in the atherosclerotic plaques, which were confirmed by histology. Histological quantification showed that the mean NWI of group I was significantly lower than those of group II and group III (P<0.05).

Conclusion

This study has confirmed the possibility of using MRI to track, in vivo, IL-10/Feridex-BMCs recruited to atherosclerotic lesions, where IL-10 genes function to prevent the progression of atherosclerosis.

Ultrasound guidance for the creation of a small animal model of aortic injury

PURPOSE

To develop a small animal model of controlled aortic intimal injury with ultrasound (US) imaging guidance.

MATERIALS AND METHODS

Via carotid artery cutdown, a custom-made microcatheter/angled metal device system was advanced to damage the intima of the ascending aortas of 20 Sprague-Dawley rats and 10 JCR atherosclerotic rats. This minimally invasive endovascular procedure was monitored by a clinical US imaging system. Injured aortas were harvested for histologic confirmation via a grading system: grade I, intima injury; grade II, injury to media; and grade III, injury through the entire aortic wall. Neointimal reactions at the injury site were compared by calculating the ratio of intimal to medial thickness among different animal groups at various survival times (week 1, weeks 2-3, and weeks 4-7).

RESULTS

Clear visualization of the architecture of the heart and great vessels and the exact location of the angled metal device by US imaging ensured consistent intimal damage of the aorta. Histopathologic analysis confirmed that most of the aortic injures were classified as grade I. There was no significant difference between the two rat groups. Analysis of pathophysiologic reactions at the injury sites revealed increased thickening of neointimal hyperplasia as animal survival times extended from week 1 to weeks 4-7 after the aortic interventions.

CONCLUSIONS

This study demonstrates the feasibility of clinical US imaging to precisely guide the creation of controlled aortic intimal injury in rats, which may become a useful tool to facilitate research involving the prevention and treatment of atherosclerotic cardiovascular disease.

Transcatheter arterial chemoembolization as primary treatment for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) in Western populations has historically been associated with poor survival.

METHODS

In this study, we conducted a 7-year retrospective analysis of patients with HCC undergoing transcatheter arterial chemoembolization (TACE) at our institution and examined demographics, outcomes, and complications.

RESULTS

During the period of study, 39 patients (25 male [64%], mean age 58 [range 17 to 86]) underwent a total of 78 chemoembolization treatments. During the same time period, an additional 31 patients received supportive care only. The majority of patients had late stage disease (American Joint Committee on Cancer stage III, IVa, or IVb) with no statistical difference noted between the two groups (P = 0.2). However, patients receiving supportive care only had significantly worse hepatic dysfunction by Child's classification (P = 0.005). Twenty-nine patients (74%) had documented cirrhosis, with hepatitis C being the most common cause in 11 of 29 (38%). In patients undergoing TACE, overall actuarial survival was 35%, 20%, and 11% at 1, 2, and 3 years with a median survival of 9.2 months, significantly improved over the group receiving supportive care only (P < 0.0001). Median survival for the group receiving supportive care was less than 3 months. Neither age nor stage had a significant impact on survival. The most common complications of TACE included transient nausea, abdominal pain, vomiting, and fever.

CONCLUSIONS

TACE is a safe and effective therapeutic option for selected patients with HCC not amenable to surgical intervention.

Hepatocellular carcinoma outcomes based on indicated treatment strategy

Hepatocellular carcinoma (HCC) in Western populations historically has been associated with poor survival. In this study, we conducted a 7-year retrospective analysis of patients evaluated at our institution with HCC to determine the effects of newer treatment strategies on outcome. During the period of study, 117 patients [86 (74%) male; mean age, 59 years (range, 16-85)] were evaluated with treatment as follows: surgical resection in 22 (19%), chemoembolization with or without systemic chemotherapy in 40 (35%), systemic treatment alone in 16 (13%), orthotopic liver transplantation in 8 (7%), and supportive care only in 31 (26%). Sixty-nine patients (59%) had documented cirrhosis, with hepatitis C being the most common cause in 27 of 69 (39%). In patients receiving no treatment, median survival was just under 3 months, with only two 1-year survivors. Patients with orthotopic liver transplantation had 1-, 2-, and 3-year survival rates of 87, 87, and 58 per cent compared with 69, 52, and 43 per cent in surgically resected patients. Survival after chemoembolization was 35, 20, and 11 per cent at 1, 2, and 3 years, whereas survival after systemic chemotherapy was 30 and 15 per cent at 1 and 2 years, respectively. One-year survival was improved in noncirrhotic patients compared with cirrhotics (47% vs 29%; P < 0.05) but was no different in patients younger than 55 years compared with older patients (38% vs 38%). When possible, surgical treatment strategies offer superior survival.

Operant (biofeedback) control of left-right frontal alpha power differences: potential neurotherapy for affective disorders

Two experiments were done with subjects from a paid pool of undergraduates. In each study, there were five 1-hour sessions on each of 5 days: (1) Baseline: Rewards given for randomly selected 20% of the 700-ms sequential epochs; mean and SD of baseline power differences determined. 2) Exploration: Subjects were rewarded when right minus left alpha differences in an epoch were greater than the baseline mean plus about .85 SD (p = .20); subjects told to discover how to generate rewards. (3)-(5). Training: Subjects were paid (over and above the $8/h flat rate) in proportion to their hit rates. In the first study (in which active filters passed 8-12 Hz activity, and the rectified, integrated amplitude was utilized), 6 of 8 subjects met learning criteria (a significant difference between baseline and training scores). In the second study (in which on-line FFTs were used to extract alpha power), 3 of 5 subjects met learning criteria.

Two-dimensional echocardiography for catheter location and placement in infants and children

This paper presents our experience with two-dimensional echocardiography in the detection of 61 intravascular catheters or wires in a series of 39 infants and children. It was possible to identify intravascular wires as small as 0.5 mm in diameter and intravascular catheters as small as 0.9 mm in diameter. In no instance, was an intravascular catheter not detected. The two-dimensional echocardiogram is demonstrated to be a tool to assist the physician in placement of intravascular catheters. In the catheterization laboratory, the two-dimensional echocardiogram is useful in determining catheter location, particularly in the presence of complex congenital defects. Two-dimensional echocardiographic guidance of catheters minimizes exposure to ionizing radiation.

Electronic factors in the structure-activity relationship of some 1,4-benzodiazepin-2-ones

Some significant correlations are observed between the CNS activities of a series of 59 benzodiazepines and some calculated electronic indices. The parameters concerned are the net charge on the carbonyl oxygen atom of the lactam ring and the total molecular dipole moment, correlations with the latter index being superior. The utility of the observed relationships is discussed.