Abstract 4056: Intratumoral delivery of autologous tumor antigen specific CD4 Th1 cells combined with dendritic cells eradicates HER2 mammary carcinoma

Human epidermal growth factor receptor 2 (HER2) overexpression accounts for 30% of invasive breast cancer (BC) and is critically associated with aggressive disease, recurrence and metastasis. Adoptive cell therapy approaches using cytotoxic CD8 T cells and natural killer cells have been shown to trigger anti-tumor immunity in BC. However, the immunosuppressive tumor microenvironment (TME) can inhibit response to these therapies and diminish the presence and function of tumor-infiltrating lymphocytes. Recently, we have shown a critical role for anti-tumor CD4 Th1 cells in dendritic cells (DC) intratumoral (i.t.) delivery in combination with anti-HER2 therapy. This combination therapy enhanced systemic and local anti-tumor immunity and eradicated tumors in HER2 positive BC with a requirement for CD4 Th1 cells. Here we investigated the efficacy of i.t. delivery of both autologous anti-tumor CD4 Th1 cells and tumor antigen pulsed type 1 polarized dendritic cells (HER2-DC1) in a HER2 mammary carcinoma model. CD4 T cells were isolated from BALB/c mice that had completely regressed (pCR) from orthotopic TUBO tumors following HER2-DC1 i.t. or combination therapy with anti-HER2 antibody. CD4 Th1 cells were then expanded by co-culturing with HER2-DC1 in the presence of interleukin (IL)-2 and IL-7 cytokines. BALB/c mice bearing orthotopic TUBO tumors were treated weekly for six weeks with anti-tumor CD4 Th1 cells i.t., non-specific CD4 Th1 cells i.t., HER2-DC1 i.t. or combination therapy. The i.t. delivery of anti-tumor CD4 Th1 cells combined with HER2-DC1 induced a strong anti-tumor response with survival benefit and complete tumor eradication in 50% of treated mice. Importantly, the i.t. delivery of anti-tumor CD4 Th1 cells were critical for providing priming signals to HER2-DC1 within the TME via CD40/CD40L engagement (licensing). This was supported by a strong anti-tumor response and complete tumor regression in 60% of orthotopic TUBO tumor bearing mice treated with CD40/CD40L licensed HER2-DC1 i.t. therapy compared to un-licensed HER2-DC1 i.t. therapy. Additionally, enhanced survival and functionality of human and mouse HER2-DC1 was observed following activation of CD40/CD40L signaling using anti-CD40 agonistic antibody in vitro. Collectively, these results suggest a new promising therapeutic strategy using DC1-anti-tumor CD4 Th1 adoptive cell therapy intratumoral delivery to induce DC1 priming and create robust anti-tumor immunity within the TME in BC.

Citation Format: Ganesan Ramamoorthi, Amy Aldrich, Colin Snyder, Brian Czerniecki. Intratumoral delivery of autologous tumor antigen specific CD4 Th1 cells combined with dendritic cells eradicates HER2 mammary carcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4056.

Long-Term CD4+ T-Cell and Immunoglobulin G Immune Responses in Oncology Workers following COVID-19 Vaccination: An Interim Analysis of a Prospective Cohort Study

We conducted a prospective study to evaluate immune responses to SARS-CoV-2 in oncology workers in which we collected blood and clinical data every 6 months. Spike-specific CD4+ T-cells and immunoglobulin G responses were measured using interferon-gamma enzyme-linked immunosorbent spot and enzyme-linked immunosorbent assay, respectively. Sixty (81%) vaccinated and 14 (19%) unvaccinated individuals were enrolled. CD4+ T-cell responses of those individuals currently naturally infected were comparable to those who were 6 months from receiving their last dose of the vaccine; both responses were significantly higher than among those who were unvaccinated. Unvaccinated participants who became vaccinated while in the study showed a significant increase in both types of spike-specific immune responses. Previously vaccinated individuals who received a third dose (booster) showed a similar response to the spike protein. However, this response decreases as soon as 3 months but does not dip below the established response following two doses. Response to variants of concern B.1.617.2 (Delta) and B.1.1.529 (Omicron) also increased, with the Omicron variant having a significantly lower response when compared to Delta and the wild type. We conclude that antibody and T-cell responses increase in oncology workers after serial vaccination but can wane over time.

3D Bioprinted Scaffolds Containing Viable Macrophages and Antibiotics Promote Clearance of Staphylococcus aureus Craniotomy-Associated Biofilm Infection

Craniotomy involves the removal of a skull fragment to access the brain, such as during tumor or epilepsy surgery, which is immediately replaced intraoperatively. The infection incidence after craniotomy ranges from 0.8 to 3%, with approximately half caused by Staphylococcus aureus ( S. aureus). To mitigate infectious complications following craniotomy, we engineered a three-dimensional (3D) bioprinted bone scaffold to harness the potent antibacterial activity of macrophages (MΦs) together with antibiotics using a mouse S. aureus craniotomy-associated biofilm model that establishes a persistent infection on the bone flap, subcutaneous galea, and brain. The 3D scaffold contained rifampin and daptomycin printed in a composite slurry, with viable MΦs incorporated into a hydrogel-based bioink, which was assessed for both the treatment and prevention of craniotomy-associated infections in the mouse model. For the treatment paradigm, the bone flap was removed at day 7 post infection after a mature biofilm had formed and was replaced with a 3D printed antibiotic scaffold, with or without MΦ incorporation. Bacterial burdens in the galea and brain were reduced by at least 100-fold at early time points, which was potentiated by bioprinting viable MΦs into the 3D antibiotic scaffold. We also examined a prevention paradigm, where the scaffolds were placed at the time of surgery and challenged with S. aureus one day later at the surgical site. Interestingly, unlike the treatment paradigm, the incorporation of viable MΦs into the 3D antibiotic scaffold did not enhance bacterial clearance compared to that of antibiotic alone. With further refinement, our 3D bioprinted scaffold represents a potential treatment modality, as it delivers therapeutic antibiotic levels more rapidly than systemic administration, based on its proximity to the infection site. In addition, the incorporation of viable MΦs into the 3D scaffold is an important advance, which demonstrated an improved therapeutic benefit for the treatment of established biofilms that represent the most clinically challenging scenario.

Efficacy of phosphodiesterase-4 inhibitors in juvenile Batten disease (CLN3)

OBJECTIVE

Juvenile neuronal ceroid lipofuscinosis (JNCL), or juvenile Batten disease, is a pediatric lysosomal storage disease caused by autosomal recessive mutations in CLN3, typified by blindness, seizures, progressive cognitive and motor decline, and premature death. Currently, there is no treatment for JNCL that slows disease progression, which highlights the need to explore novel strategies to extend the survival and quality of life of afflicted children. Cyclic adenosine monophosphate (cAMP) is a second messenger with pleiotropic effects, including regulating neuroinflammation and neuronal survival. Here we investigated whether 3 phosphodiesterase-4 (PDE4) inhibitors (rolipram, roflumilast, and PF-06266047) could mitigate behavioral deficits and cell-specific pathology in the Cln3^Δex7/8 mouse model of JNCL.

METHODS

In a randomized, blinded study, wild-type (WT) and Cln3^Δex7/8 mice received PDE4 inhibitors daily beginning at 1 or 3 months of age and continuing for 6 to 9 months, with motor deficits assessed by accelerating rotarod testing. The effect of PDE4 inhibitors on cAMP levels, astrocyte and microglial activation (glial fibrillary acidic protein and CD68, respectively), lysosomal pathology (lysosomal-associated membrane protein 1), and astrocyte glutamate transporter expression (glutamate/aspartate transporter) were also examined in WT and Cln3^Δex7/8 animals.

RESULTS

cAMP levels were significantly reduced in the Cln3^Δex7/8 brain, and were restored by PF-06266047. PDE4 inhibitors significantly improved motor function in Cln3^Δex7/8 mice, attenuated glial activation and lysosomal pathology, and restored glutamate transporter expression to levels observed in WT animals, with no evidence of toxicity as revealed by blood chemistry analysis.

INTERPRETATION

These studies reveal neuroprotective effects for PDE4 inhibitors in Cln3^Δex7/8 mice and support their therapeutic potential in JNCL patients. Ann Neurol 2016;80:909-923.

Critical role for the AIM2 inflammasome during acute CNS bacterial infection

Interleukin-1β (IL-1β) is essential for eliciting protective immunity during the acute phase of Staphylococcus aureus (S. aureus) infection in the central nervous system (CNS). We previously demonstrated that microglial IL-1β production in response to live S. aureus is mediated through the Nod-like receptor protein 3 (NLRP3) inflammasome, including the adapter protein ASC (apoptosis-associated speck-like protein containing a caspase-1 recruitment domain), and pro-caspase 1. Here, we utilized NLRP3, ASC, and caspase 1/11 knockout (KO) mice to demonstrate the functional significance of inflammasome activity during CNS S. aureus infection. ASC and caspase 1/11 KO animals were exquisitely sensitive, with approximately 50% of mice succumbing to infection within 24 h. Unexpectedly, the survival of NLRP3 KO mice was similar to wild-type animals, suggesting the involvement of an alternative upstream sensor, which was later identified as absent in melanoma 2 (AIM2) based on the similar disease patterns between AIM2 and ASC KO mice. Besides IL-1β, other key inflammatory mediators, including IL-6, CXCL1, CXCL10, and CCL2 were significantly reduced in the CNS of AIM2 and ASC KO mice, implicating autocrine/paracrine actions of IL-1β, as these mediators do not require inflammasome processing for secretion. These studies demonstrate a novel role for the AIM2 inflammasome as a critical molecular platform for regulating IL-1β release and survival during acute CNS S. aureus infection.

Compartmentalization of immune responses during Staphylococcus aureus cranial bone flap infection

Decompressive craniectomy is often required after head trauma, stroke, or cranial bleeding to control subsequent brain swelling and prevent death. The infection rate after cranial bone flap replacement ranges from 0.8% to 15%, with an alarming frequency caused by methicillin-resistant Staphylococcus aureus, which is problematic because of recalcitrance to antibiotic therapy. Herein we report the establishment of a novel mouse model of S. aureus cranial bone flap infection that mimics several aspects of human disease. Bacteria colonized bone flaps for up to 4 months after infection, as revealed by scanning electron microscopy and quantitative culture, demonstrating the chronicity of the model. Analysis of a human cranial bone flap with confirmed S. aureus infection by scanning electron microscopy revealed similar structural attributes as the mouse model, demonstrating that it closely parallels structural facets of human disease. Inflammatory indices were most pronounced within the subcutaneous galeal compartment compared with the underlying brain parenchyma. Specifically, neutrophil influx and chemokine expression (CXCL2 and CCL5) were markedly elevated in the galea, which demonstrated substantial edema on magnetic resonance images, whereas the underlying brain parenchyma exhibited minimal involvement. Evaluation of immune mechanisms required for bacterial containment and inflammation revealed critical roles for MyD88-dependent signaling and neutrophils. This novel mouse model of cranial bone flap infection can be used to identify key immunologic and therapeutic mechanisms relevant to persistent bone flap infection in humans.

Central nervous system fibrosis is associated with fibrocyte-like infiltrates

Fibrotic wall formation is essential for limiting pathogen dissemination during brain abscess development. However, little is known about the regulation of fibrotic processes in the central nervous system (CNS). Most CNS injury responses are associated with hypertrophy of resident astrocytes, a process termed reactive gliosis. Studies of fibrosis outside the CNS have identified two bone marrow-derived cell types, fibrocytes and alternatively activated M2 macrophages, as key mediators of fibrosis. The current study used bone marrow chimeras generated from green fluorescent protein transgenic mice to evaluate the appearance of these cell types and whether bone marrow-derived cells were capable of acquiring fibrotic characteristics during brain abscess development. Immunofluorescence staining revealed partial overlap between green fluorescent protein, α-smooth muscle actin, and procollagen, suggesting that a population of cells forming the brain abscess capsule originate from a bone marrow precursor. In addition, the influx of fibrocyte-like cells into brain abscesses immediately preceded the onset of fibrotic encapsulation. Fibrotic wall formation was also associated with increased numbers of alternatively activated M2 microglia and macrophages. To our knowledge, this is the first study demonstrating that bone marrow-derived infiltrates are capable of expressing fibrotic molecules during CNS inflammation.

Roles of Toll-like receptor 2 (TLR2) and superantigens on adaptive immune responses during CNS staphylococcal infection

Staphylococcus aureus is a common etiologic agent of brain abscesses and possesses numerous virulence factors that manipulate host immunity. One example is superantigens (SAG) that clonally expand T cell subsets bearing specific Vβ receptors. Toll-like receptor 2 (TLR2) is one receptor implicated in S. aureus recognition. However, the interplay between TLR2, SAG, and adaptive immunity during brain abscess formation has not yet been investigated and could reveal novel insights into host-pathogen interactions for regulating protective immunity. A comprehensive analysis of abscess-associated T cell populations in TLR2 KO and WT mice was performed following infection with a S. aureus clinical isolate. Both natural killer T (NKT) and γδ T cell infiltrates were increased in brain abscesses of TLR2 KO mice and produced more IL-17 and IFN-γ compared to WT populations, which could have resulted from elevated bacterial burdens observed in these animals. Analysis of SAG-reactive T cells revealed a predominant Vβ(8.1,8.2) infiltrate reactive with staphylococcal enterotoxin B (SEB), whereas SEA-reactive Vβ(11) T cells were less numerous. Brain abscesses of TLR2 KO mice had fewer Vβ(8.1,8.2) and Vβ(11) T cells and produced less TNF-α and IFN-γ compared to WT animals. Treatment of primary microglia with purified SEB augmented TNF-α production in response to the TLR2 ligand Pam3Cys, which may serve to amplify proinflammatory cascades during CNS S. aureus infection. Collectively, these studies demonstrate that TLR2 impacts adaptive immunity to S. aureus infection and modulates SAG responses.

Staphylococcus aureus biofilms prevent macrophage phagocytosis and attenuate inflammation in vivo

Biofilms are complex communities of bacteria encased in a matrix composed primarily of polysaccharides, extracellular DNA, and protein. Staphylococcus aureus can form biofilm infections, which are often debilitating due to their chronicity and recalcitrance to antibiotic therapy. Currently, the immune mechanisms elicited during biofilm growth and their impact on bacterial clearance remain to be defined. We used a mouse model of catheter-associated biofilm infection to assess the functional importance of TLR2 and TLR9 in the host immune response during biofilm formation, because ligands for both receptors are present within the biofilm. Interestingly, neither TLR2 nor TLR9 impacted bacterial density or inflammatory mediator secretion during biofilm growth in vivo, suggesting that S. aureus biofilms circumvent these traditional bacterial recognition pathways. Several potential mechanisms were identified to account for biofilm evasion of innate immunity, including significant reductions in IL-1β, TNF-α, CXCL2, and CCL2 expression during biofilm infection compared with the wound healing response elicited by sterile catheters, limited macrophage invasion into biofilms in vivo, and a skewing of the immune response away from a microbicidal phenotype as evidenced by decreases in inducible NO synthase expression concomitant with robust arginase-1 induction. Coculture studies of macrophages with S. aureus biofilms in vitro revealed that macrophages successful at biofilm invasion displayed limited phagocytosis and gene expression patterns reminiscent of alternatively activated M2 macrophages. Collectively, these findings demonstrate that S. aureus biofilms are capable of attenuating traditional host proinflammatory responses, which may explain why biofilm infections persist in an immunocompetent host.

Targeting GLI1 expression in human inflammatory breast cancer cells enhances apoptosis and attenuates migration

Background:

Inflammatory breast cancer (IBC) is an aggressive subtype of breast cancer with distinct molecular profiles. Gene expression profiling previously identified sonic hedgehog (SHH) as part of a gene signature that is differentially regulated in IBC patients.

Methods:

The effects of reducing GLI1 levels on protein expression, cell proliferation, apoptosis and migration were determined by immunoblots, MTT assay, Annexin-V/PI assay and conventional and automated cell migration assays.

Results:

Evaluation of a panel of breast cancer cell lines revealed elevated GLI1 expression, typically a marker for hedgehog-pathway activation, in a triple-negative, highly invasive IBC cell line, SUM149 and its isogenic-derived counterpart rSUM149 that has acquired resistance to ErbB1/2 targeting strategies. Downregulation of GLI1 expression in SUM149 and rSUM149 by small interfering RNA or a small molecule GLI1 inhibitor resulted in decreased proliferation and increased apoptosis. Further, GLI1 suppression in these cell lines significantly inhibited cell migration as assessed by a wound-healing assay compared with MCF-7, a non-invasive cell line with low GLI1 expression. A novel high-content migration assay allowed us to quantify multiple effects of GLI1 silencing including significant decreases in cell distance travelled and linearity of movement.

Conclusion:

Our data reveal a role for GLI1 in IBC cell proliferation, survival and migration, which supports the feasibility of targeting GLI1 as a novel therapeutic strategy for IBC patients.

Abstract B67: Establishment of a high-content assay to assess the affects of gene silencing on inflammatory breast cancer cell motility

Inflammatory breast cancer (IBC) is an aggressive, highly invasive tumor with one of the worst clinical outcome among breast cancers with rapid clinical progression and resistance to chemotherapy and radiotherapy. Epidemiologic data show that IBC affects women at a younger age (58.8 years vs. 66.2 years for locally advanced breast cancer (LABC)) and minorities (African Americans, Hispanics, and Native Americans) are disproportionately affected. Taken together, the clinical and epidemiological data demonstrate that IBC is in fact a distinct entity from LABC, and therefore more work is required to elucidate the unique molecular characteristics of IBC that will allow for targeted treatment regimens. We have previously shown that elevated expression of Gli1 mRNA, typically a marker for Hh pathway activation, was observed in the SUM149 IBC cell line, compared to a panel of other IBC and non-IBC cell lines, and that Gli1 silencing in SUM149 using siRNA resulted in decreased proliferation and increased apoptosis. SUM149 cells were generated from an aggressive inflammatory breast cancer and have been characterized as a (ErbB2-, ER- and PR-) basal B subtype of breast cancer cell, which is frequently more invasive than other breast cancer cell types. Hence, we also wanted to investigate whether the high levels of Gli1 in SUM149 cells play a role in its unique migratory phenotype. In our study, we first used a conventional in vitro wound healing assay as a measure of migration and found that silencing of Gli1 in SUM149 cells dramatically reduces SUM149 cell migration over 24 hours. To glean more quantitative information from the motility wound healing assay, we were interested in developing high content imaging assays that would also extract other critical parameters defining migration behavior. The advantages of the wound healing assay are that it can be miniaturized and is compatible with microscopy making it amenable to high throughput imaging. Such a high content automated microscopy system allows the analysis of both population and single-cell data on a heterogeneous population of cells and potentially link phenotypic variability to genetic differences. To obtain a more quantitative assessment and further assess the role of Gli1 in the migratory phenotype of SUM149, we tagged SUM149 cells with green fluorescent protein-histone2B (GFP-H2B) to fluorescently label nuclei of living cells and using a high content live cell fluorescence-based imaging system demonstrated that we can track not only cell migration but additional parameters of motility such as linearity of movement and, integrated distance traveled. Many features of each cellular trajectory were tabulated and compared for the experimental conditions and both average linearity and distance traveled were reduced in SUM149 cells with Gli1 silenced. We expect this type of multi-parameter analysis of cell migration after GFP-H2B tagging to be generally applicable to many cell types to assess affects on motility.

Grant Support: NIH grant CA137844 (K. P. Williams) and American Cancer Society grant RSG-08-290-01 -CCE (G. R. Devi). K. P. W. and G. R. D. co-senior authors.

Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):B67.

A novel splice variant of GLI1 that promotes glioblastoma cell migration and invasion

The family of GLI zinc finger transcription factors regulates the expression of genes involved in many important cellular processes, notably embryonal development and cellular differentiation. The glioma-associated oncogene homologue 1 (GLI1) isoform, in particular, has attracted much attention because of its frequent activation in many human cancers and its interactions with other signaling pathways, such as those mediated by K-RAS, transforming growth factor-beta, epidermal growth factor receptor, and protein kinase A. Here, we report the identification of a novel truncated GLI1 splice variant, tGLI1, with an in-frame deletion of 123 bases (41 codons) spanning the entire exon 3 and part of exon 4 of the GLI1 gene. Expression of tGLI1 is undetectable in normal cells but is high in glioblastoma multiforme (GBM) and other cancer cells. Although tGLI1 undergoes nuclear translocalization and transactivates GLI1-binding sites similar to GLI1, unlike GLI1, it is associated with increased motility and invasiveness of GBM cells. Using microarray analysis, we showed >100 genes to be differentially expressed in tGLI1-expressing compared with GLI1-expressing GBM cells, although both cell types expressed equal levels of known GLI1-regulated genes, such as PTCH1. We further showed one of the tGLI1 up-regulated genes, CD24, an invasion-associated gene, to be required for the migratory and invasive phenotype of GBM cells. These data provide conclusive evidence for a novel gain-of-function GLI1 splice variant that promotes migration and invasiveness of GBM cells and open up a new research paradigm on the role of the GLI1 pathway in malignancy.

Community care for late adolescents

This paper describes supportive accommodation for late adolescents in Cambridge provided by the Castle Project in conjunction with the Young People's Psychiatric Service. It outlines the characteristics of young people referred to the Project over the first years of its existence, their lengths of stay and next moves, and suggests that there are members of two groups, those with schizophrenic-type disorders and those with pronounced antisocial behaviour, who present long-term problems of care and accommodation and whose needs are not yet catered for appropriately.