Intestinal Radiation Protection and Mitigation by Second-Generation Probiotic Lactobacillus-reuteri Engineered to Deliver Interleukin-22.

(1) Background: The systemic administration of therapeutic agents to the intestine including cytokines, such as Interleukin-22 (IL-22), is compromised by damage to the microvasculature 24 hrs after total body irradiation (TBI). At that time, there is significant death of intestinal microvascular endothelial cells and destruction of the lamina propria, which limits drug delivery through the circulation, thus reducing the capacity of therapeutics to stabilize the numbers of Lgr5+ intestinal crypt stem cells and their progeny, and improve survival. By its direct action on intestinal stem cells and their villus regeneration capacity, IL-22 is both an ionizing irradiation protector and mitigator. (2) Methods: To improve delivery of IL-22 to the irradiated intestine, we gavaged Lactobacillus-reuteri as a platform for the second-generation probiotic Lactobacillus-reuteri-Interleukin-22 (LR-IL-22). (3) Results: There was effective radiation mitigation by gavage of LR-IL-22 at 24 h after intestinal irradiation. Multiple biomarkers of radiation damage to the intestine, immune system and bone marrow were improved by LR-IL-22 compared to the gavage of control LR or intraperitoneal injection of IL-22 protein. (4) Conclusions: Oral administration of LR-IL-22 is an effective protector and mitigator of intestinal irradiation damage.

Multiplex profiling identifies distinct local and systemic alterations during intraperitoneal chemotherapy for ovarian cancer: An NRG Oncology/Gynecologic Oncology Group Study.

OBJECTIVES: Ovarian cancer leads to abdominal carcinomatosis and late stage (III/IV) diagnosis in 75% of patients. Three randomized phase III trials have demonstrated that intraperitoneal (IP) chemotherapy improves outcomes in epithelial ovarian cancer. While IP treatment is validated by clinical trials, there is a poor understanding of the mechanism(s) leading to the survival advantage other than the increased concentration of cytotoxic drugs within the tumor microenvironment. A better understanding of this process through analysis of dynamic biomarkers should promote novel approaches that may enhance tumor clearance. We propose this pilot study to confirm the feasibility of collecting serial peritoneal samples from implanted catheters in women receiving IP chemotherapy. We believe these specimens may be used for multiplex analysis to reveal unique biomarker fluctuations when compared to peripheral blood. METHODS: From 13 women participating on GOG 252, 30 whole blood, 12 peritoneal fluid (PF), and 20 peritoneal wash (PW) with 30mL saline were obtained. Samples were requested prior to the first three chemotherapy cycles. Samples were assessed for volume, cell populations, protein, RNA, and miRNA content changes. RESULTS: Median volume for PF was 1.6mL and 3.1mL for PW. PW is a dilution of PF capable of capturing measurable biomarkers. Peritoneal aspirates contain a unique profile of biomarkers distinct from blood. miRNA undergo earlier alteration with chemotherapy than genes. Flow cytometry does not adequately capture biomarker fluctuations. CONCLUSIONS: As a proof of principle study, this trial provides evidence that sampling the peritoneal cavity can be adapted for biomarker analysis.

Anti-PD-L1 prolongs survival and triggers T cell but not humoral anti-tumor immune responses in a human MUC1-expressing preclinical ovarian cancer model.

Monoclonal antibodies that block inhibitory immune checkpoint molecules and enhance anti-tumor responses show clinical promise in advanced solid tumors. Most of the preliminary evidence on therapeutic efficacy of immune checkpoint blockers comes from studies in melanoma, lung and renal cancer. To test the in vivo potential of programmed death-ligand 1 (PD-L1) blockade in ovarian cancer, we recently generated a new transplantable tumor model using human mucin 1 (MUC1)-expressing 2F8 cells. The MUC1 transgenic (MUC1.Tg) mice develop large number of intraperitoneal (IP) tumors following IP injection of 8 × 10(5) syngeneic 2F8 cells. The tumors are aggressive and display little T cell infiltration. Anti-PD-L1 antibody was administered IP every 2 weeks (200 µg/dose) for a total of three doses. Treatment was started 21 days post-tumor challenge, a time point which corresponds to late tumor stage. The anti-PD-L1 treatment led to substantial T cell infiltration within the tumor and significantly increased survival (p = 0.001) compared to isotype control-treated mice. When the same therapy was administered to wild-type mice challenged with 2F8 tumors, no survival benefit was observed, despite the presence of high titer anti-MUC1 antibodies. However, earlier treatment (day 11) and higher frequency of IP injections restored the T cell responses and led to prolonged survival. Splenocyte profiling via Nanostring using probes for 511 immune genes revealed a treatment-induced immune gene signature consistent with increased T cell-mediated immunity. These findings strongly support further preclinical and clinical strategies exploring PD-L1 blockade in ovarian cancer.

Folate receptor-targeted multimodality imaging of ovarian cancer in a novel syngeneic mouse model.

A new transplantable ovarian tumor model is presented using a novel folate receptor (FR) positive, murine ovarian cancer cell line that emulates the human disease and induces widespread intraperitoneal (i.p.) tumors in immunocompetent mice within 4-8 weeks of implantation. Tumor development was monitored using a new positron emission tomography (PET) FR-targeting reporter with PET/computerized tomography (PET/CT) and fluorescence molecular tomography (FMT) using a commercial FR-targeting reporter. Conventional structural magnetic resonance imaging (MRI) was also performed. Adult female C57BL/6 mice were injected i.p. with 6 × 10(6) MKP-L FR+ cells. Imaging was performed weekly beginning 2 weeks after tumor induction. The albumin-binding, FR-targeting ligand cm09 was radiolabeled with the positron emitter (68)Ga and used to image the tumors with a small animal PET/CT. The FR-reporter FolateRSense 680 (PerkinElmer) was used for FMT and flow cytometry. Preclinical MRI (7 T) without FR-targeting was compared with the PET and FMT molecular imaging. Tumors were visible by all three imaging modalities. PET/CT had the highest imaging sensitivity at 3-3.5 h postadministration (mean %IA/g mean > 6) and visualized tumors earlier than the other two modalities with lower kidney uptake (mean %IA/g mean < 17) than previously reported FR-targeting agents in late stage disease. FMT showed relatively low FR-targeted agent in the bladder and kidneys, but yielded the lowest anatomical image resolution. MRI produced the highest resolution images, but it was difficult to distinguish tumors from abdominal organs during early progression since a FR-targeting MRI reporter was not used. Nevertheless, there was good correlation of imaging biomarkers between the three modalities. Tumors in the mouse ovarian cancer model could be detected using FR-targeted imaging as early as 2 weeks post i.p. injection of tumor cells. An imaging protocol should combine one or more of the modalities, e.g., PET/CT or PET/MRI for optimal tumor detection and delineation from surrounding tissues.

Upregulation of the ATR-CHEK1 pathway in oral squamous cell carcinomas.

The ATR-CHEK1 pathway is upregulated and overactivated in Ataxia Telangiectasia (AT) cells, which lack functional ATM protein. Loss of ATM in AT confers radiosensitivity, although ATR-CHEK1 pathway overactivation compensates, leads to prolonged G(2) arrest after treatment with ionizing radiation (IR), and partially reverses the radiosensitivity. We observed similar upregulation of the ATR-CHEK1 pathway in a subset of oral squamous cell carcinoma (OSCC) cell lines with ATM loss. In the present study, we report copy number gain, amplification, or translocation of the ATR gene in 8 of 20 OSCC cell lines by FISH; whereas the CHEK1 gene showed copy number loss in 12 of 20 cell lines by FISH. Quantitative PCR showed overexpression of both ATR and CHEK1 in 7 of 11 representative OSCC cell lines. Inhibition of ATR or CHEK1 with their respective siRNAs resulted in increased sensitivity of OSCC cell lines to IR by the colony survival assay. siRNA-mediated ATR or CHEK1 knockdown led to loss of G(2) cell cycle accumulation and an increased sub-G(0) apoptotic cell population by flow cytometric analysis. In conclusion, the ATR-CHEK1 pathway is upregulated in a subset of OSCC with distal 11q loss and loss of the G(1) phase cell cycle checkpoint. The upregulated ATR-CHEK1 pathway appears to protect OSCC cells from mitotic catastrophe by enhancing the G(2) checkpoint. Knockdown of ATR and/or CHEK1 increases the sensitivity of OSCC cells to IR. These findings suggest that inhibition of the upregulated ATR-CHEK1 pathway may enhance the efficacy of ionizing radiation treatment of OSCC.

Genetically Engineered Probiotic Limosilactobacillus reuteri Releasing IL-22 (LR-IL-22) Modifies the Tumor Microenvironment, Enabling Irradiation in Ovarian Cancer.

Despite recent advances in cancer therapy, ovarian cancer remains the most lethal gynecological cancer worldwide, making it crucial and of the utmost importance to establish novel therapeutic strategies. Adjuvant radiotherapy has been assessed historically, but its use was limited by intestinal toxicity. We recently established the role of Limosilactobacillus reuteri in releasing IL-22 (LR-IL-22) as an effective radiation mitigator, and we have now assessed its effect in an ovarian cancer mouse model. We hypothesized that an LR-IL-22 gavage would enable intestinal radioprotection by modifying the tumor microenvironment and, subsequently, improving overall survival in female C57BL/6MUC-1 mice with widespread abdominal syngeneic 2F8cis ovarian cancer. Herein, we report that the LR-IL-22 gavage not only improved overall survival in mice when combined with a PD-L1 inhibitor by inducing differential gene expression in irradiated stem cells but also induced PD-L1 protein expression in ovarian cancer cells and mobilized CD8+ T cells in whole abdomen irradiated mice. The addition of LR-IL-22 to a combined treatment modality with fractionated whole abdomen radiation (WAI) and systemic chemotherapy and immunotherapy regimens can facilitate a safe and effective protocol to reduce tumor burden, increase survival, and improve the quality of life of a locally advanced ovarian cancer patient.

Human mucin MUC1 RNA undergoes different types of alternative splicing resulting in multiple isoforms.

MUC1 is a transmembrane mucin with important functions in normal and transformed cells, carried out by the extracellular domain or the cytoplasmic tail. A characteristic feature of the MUC1 extracellular domain is the variable number of tandem repeats (VNTR) region. Alternative splicing may regulate MUC1 expression and possibly function. We developed an RT-PCR method for efficient isolation of MUC1 mRNA isoforms that allowed us to evaluate the extent of alternative splicing of MUC1 and elucidate some of the rules that govern this process. We cloned and analyzed 21, 24, and 36 isoforms from human tumor cell lines HeLa, MCF7, and Jurkat, respectively, and 16 from normal activated human T cells. Among the 78 MUC1 isoforms we isolated, 76 are new and different cells showed varied MUC1 expression patterns. The VNTR region of exon 2 was recognized as an intron with a fixed 5' splice site but variable 3' splice sites. We also report that the 3506 A/G SNP in exon 2 can regulate 3' splice sites selection in intron 1 and produce different MUC1 short isoform proteins. Furthermore, the SNP A to G mutation was also observed in vivo, during de novo tumor formation in MUC1(+/-)Kras(G12D/+)Pten(loxP/loxP) mice. No specific functions have been associated with previously reported short isoforms. We now report that one new G SNP-associated isoform MUC1/Y-LSP, but not the A SNP-associated isoform MUC1/Y, inhibits tumor growth in immunocompetent but not immunocompromised mice.

Quiescent Ovarian Cancer Cells Secrete Follistatin to Induce Chemotherapy Resistance in Surrounding Cells in Response to Chemotherapy.

PURPOSE: We recently reported that the transcription factor NFATC4, in response to chemotherapy, drives cellular quiescence to increase ovarian cancer chemoresistance. The goal of this work was to better understand the mechanisms of NFATC4-driven ovarian cancer chemoresistance. EXPERIMENTAL DESIGN: We used RNA sequencing to identify NFATC4-mediated differential gene expression. CRISPR-Cas9 and FST (follistatin)-neutralizing antibodies were used to assess impact of loss of FST function on cell proliferation and chemoresistance. ELISA was used to quantify FST induction in patient samples and in vitro in response to chemotherapy. RESULTS: We found that NFATC4 upregulates FST mRNA and protein expression predominantly in quiescent cells and FST is further upregulated following chemotherapy treatment. FST acts in at least a paracrine manner to induce a p-ATF2-dependent quiescent phenotype and chemoresistance in non-quiescent cells. Consistent with this, CRISPR knockout (KO) of FST in ovarian cancer cells or antibody-mediated neutralization of FST sensitizes ovarian cancer cells to chemotherapy treatment. Similarly, CRISPR KO of FST in tumors increased chemotherapy-mediated tumor eradication in an otherwise chemotherapy-resistant tumor model. Suggesting a role for FST in chemoresistance in patients, FST protein in the abdominal fluid of patients with ovarian cancer significantly increases within 24 hours of chemotherapy exposure. FST levels decline to baseline levels in patients no longer receiving chemotherapy with no evidence of disease. Furthermore, elevated FST expression in patient tumors is correlated with poor progression-free, post-progression-free, and overall survival. CONCLUSIONS: FST is a novel therapeutic target to improve ovarian cancer response to chemotherapy and potentially reduce recurrence rates.

Immunotherapy with IL12 and PD1/CTLA4 inhibition is effective in advanced ovarian cancer and associates with reversal of myeloid cell-induced immunosuppression.

The tumor microenvironment (TME) in ovarian cancer (OC) is characterized by immune suppression, due to an abundance of suppressive immune cells populations. To effectively enhance the activity of immune checkpoint inhibition (ICI), there is a need to identify agents that target these immunosuppressive networks while promoting the recruitment of effector T cells into the TME. To this end, we sought to investigate the effect of the immunomodulatory cytokine IL12 alone or in combination with dual-ICI (anti-PD1 + anti-CTLA4) on anti-tumor activity and survival, using the immunocompetent ID8-VEGF murine OC model. Detailed immunophenotyping of peripheral blood, ascites, and tumors revealed that durable treatment responses were associated with reversal of myeloid cell-induced immune suppression, which resulted in enhanced anti-tumor activity by T cells. Single cell transcriptomic analysis further demonstrated striking differences in the phenotype of myeloid cells from mice treated with IL12 in combination with dual-ICI. We also identified marked differences in treated mice that were in remission compared to those whose tumors progressed, further confirming a pivotal role for the modulation of myeloid cell function to allow for response to immunotherapy. These findings provide the scientific basis for the combination of IL12 and ICI to improve clinical response in OC.

Release of Interferon-ß (IFN-ß) from Probiotic Limosilactobacillus reuteri-IFN-ß (LR-IFN-ß) Mitigates Gastrointestinal Acute Radiation Syndrome (GI-ARS) following Whole Abdominal Irradiation.

Irradiation can be an effective treatment for ovarian cancer, but its use is limited by intestinal toxicity. Thus, strategies to mitigate toxicity are important and can revitalize the current standard of care. We previously established that LR-IL-22 protects the intestine from WAI. We now hypothesize that LR-IFN-ß is an effective radiation protector and mitigator and is rapidly cleared from the digestive tract, making it an option for intestinal radioprotection. We report that the gavage of LR-IFN-ß during WAI provides improved intestinal barrier integrity and significantly preserves the numbers of Lgr5+GFP+ intestinal stem cells, improving survival. The rapid clearance of the genetically engineered probiotic from the digestive tract renders it a safe and feasible radiation mitigator. Therefore, the above genetically engineered probiotic is both a feasible and effective radiation mitigator that could potentially revolutionize the management of OC patients. Furthermore, the subsequent addition of platinum/taxane-based chemotherapy to the combination of WAI and LR-IFN-ß should reduce tumor volume while protecting the intestine and should improve the overall survival in OC patients.

Longitudinal Modulation of Loco-Regional Immunity in Ovarian Cancer Patients Receiving Intraperitoneal Chemotherapy.

The immune tumor microenvironment (TME) of epithelial ovarian cancer (EOC) carries both effector and suppressive functions. To define immune correlates of chemotherapy-induced tumor involution, we performed longitudinal evaluation of biomarker expression on serial biological specimens collected during intraperitoneal (IP) platinum-based chemotherapy. Serial biological samples were collected at several time points during IP chemotherapy. RNA from IP fluid cells and tumor tissue was analyzed via NanoString. Meso Scale Discovery (MSD) multiplex assay and ELISA for MUC1 antibodies were performed on plasma and IP fluid. Differentially expressed genes in IP fluid demonstrate an upregulation of B cell function and activation of Th2 immune response along with dampening of Th1 immunity during chemotherapy. MSD analysis of IP fluid and gene expression analysis of tumor tissue revealed activation of Th2 immunity and the complement system. Anti-MUC1 antibodies were detected in IP fluid samples. IP fluid analysis in a secondary cohort also identified chemotherapy-induced B cell function genes. This study shows that serial IP fluid sampling is an effective method to capture changes in the immune TME during chemotherapy and reveals treatment induced changes in B cell function and Th2 immunity.

Phase I Trial Combining Chemokine-Targeting with Loco-Regional Chemoimmunotherapy for Recurrent, Platinum-Sensitive Ovarian Cancer Shows Induction of CXCR3 Ligands and Markers of Type 1 Immunity.

PURPOSE: Increased prevalence of cytotoxic T lymphocytes (CTL) in the tumor microenvironment (TME) predicts positive outcomes in patients with epithelial ovarian cancer (EOC), whereas the regulatory T cells (Treg) predict poor outcomes. Guided by the synergistic activity of TLR3 ligands, IFNα, and COX-2 blockers in selectively enhancing CTL-attractants but suppressing Treg-attractants, we tested a novel intraperitoneal chemoimmunotherapy combination (CITC), to assess its tolerability and TME-modulatory impact in patients with recurrent EOC. PATIENTS AND METHODS: Twelve patients were enrolled in phase I portion of the trial NCT02432378, and treated with intraperitoneal cisplatin, intraperitoneal rintatolimod (dsRNA, TLR3 ligand), and oral celecoxib (COX-2 blocker). Patients in cohorts 2, 3, and 4 also received intraperitoneal IFNα at 2, 6, and 18 million units (MU), respectively. Primary objectives were to evaluate safety, identify phase 2 recommended dose (P2RD), and characterize changes in the immune TME. Peritoneal resident cells and intraperitoneal wash fluid were profiled via NanoString and Meso Scale Discovery (MSD) multiplex assay, respectively. RESULTS: The P2RD of IFNα was 6 MU. Median progression-free survival and overall survival were 8.4 and 30 months, respectively. Longitudinal sampling of the peritoneal cavity via intraperitoneal washes demonstrated local upregulation of IFN-stimulated genes (ISG), including CTL-attracting chemokines (CXCL-9, -10, -11), MHC I/II, perforin, and granzymes. These changes were present 2 days after chemokine modulation and subsided within 1 week. CONCLUSIONS: The chemokine-modulating intraperitoneal-CITC is safe, tolerable, and associated with ISG changes that favor CTL chemoattraction and function. This combination (plus DC vaccine) will be tested in a phase II trial. See related commentary by Aranda et al., p. 1993.

Endometriosis-Associated Mesenchymal Stem Cells Support Ovarian Clear Cell Carcinoma through Iron Regulation.

Ovarian clear cell carcinoma (OCCC) is a deadly and treatment-resistant cancer, which arises within the unique microenvironment of endometriosis. In this study, we identified a subset of endometriosis-derived mesenchymal stem cells (enMSC) characterized by loss of CD10 expression that specifically support OCCC growth. RNA sequencing identified alterations in iron export in CD10-negative enMSCs and reciprocal changes in metal transport in cocultured OCCC cells. CD10-negative enMSCs exhibited elevated expression of iron export proteins hephaestin and ferroportin and donate iron to associated OCCCs, functionally increasing the levels of labile intracellular iron. Iron is necessary for OCCC growth, and CD10-negative enMSCs prevented the growth inhibitory effects of iron chelation. In addition, enMSC-mediated increases in OCCC iron resulted in a unique sensitivity to ferroptosis. In vitro and in vivo, treatment with the ferroptosis inducer erastin resulted in significant death of cancer cells grown with CD10-negative enMSCs. Collectively, this work describes a novel mechanism of stromal-mediated tumor support via iron donation. This work also defines an important role of endometriosis-associated MSCs in supporting OCCC growth and identifies a critical therapeutic vulnerability of OCCC to ferroptosis based on stromal phenotype. SIGNIFICANCE: Endometriosis-derived mesenchymal stem cells support ovarian clear cell carcinoma via iron donation necessary for cancer growth, which also confers sensitivity to ferroptosis-inducing therapy.

Lactobacillus reuteri Releasing IL-22 (LR-IL-22) Facilitates Intestinal Radioprotection for Whole-Abdomen Irradiation (WAI) of Ovarian Cancer.

Oral administration (gavage) of a second-generation probiotic, Lactobacillus reuteri (L. reuteri), that releases interleukin-22 (LR-IL-22) at 24 h after total-body irradiation (TBI) mitigates damage to the intestine. We determined that LR-IL-22 also mitigates partial-body irradiation (PBI) and whole-abdomen irradiation (WAI). Irradiation can be an effective treatment for ovarian cancer, but its use is limited by intestinal toxicity. Strategies to mitigate toxicity are important and can revitalize this modality to treat ovarian cancer. In the present studies, we evaluated whether LR-IL-22 facilitates fractionated WAI in female C57BL/6 mice with disseminated ovarian cancer given a single fraction of either 15.75 Gy or 19.75 Gy or 4 daily fractions of 6 Gy or 6.5 Gy. Mice receiving single or multiple administrations of LR-IL-22 during WAI showed improved intestinal barrier integrity (P = 0.0167), reduced levels of radiation-induced intestinal cytokines including KC/CXCL1 (P = 0.002) and IFN-γ (P = 0.0024), and reduced levels of plasma, Eotaxin/CCL11 (P = 0.0088). LR-IL-22 significantly preserved the numbers of Lgr5+GFP+ intestinal stem cells (P = 0.0010) and improved survival (P < 0.0343). Female C57BL/6MUC-1 mice with widespread abdominal syngeneic 2F8cis ovarian cancer that received LR-IL-22 during 6.5 Gy WAI in 4 fractions had reduced tumor burden, less intestinal toxicity, and improved 30-day survival. Furthermore, LR-IL-22 facilitated WAI when added to Paclitaxel and Carboplatin chemotherapy and further increased survival. Oral administration (gavage) of LR-IL-22 is a potentially valuable intestinal radioprotector, which can facilitate therapeutic WAI for widespread intra-abdominal ovarian cancer.

Soluble MUC1 and serum MUC1-specific antibodies are potential prognostic biomarkers for platinum-resistant ovarian cancer.

MUC1 (CA15-3) and MUC16 (CA125) tumor-associated antigens are upregulated in ovarian cancer and can be detected in patients' sera by standardized tests. We postulated that increased MUC1 and MUC16 antigens augment antibody responses in platinum-resistant ovarian cancer patients and that the frequency and intensity of these responses can be used as immune biomarkers of treatment response and disease outcome. We measured MUC1 and MUC16 tumor expression by immunohistochemistry (IHC), assessed serum antigenic levels and quantitated circulating antibodies by ELISA in a cohort of 28 ovarian cancer patients with platinum-resistant or platinum-refractory ovarian cancer, and treated with intraperitoneal (IP) interleukin-2 (IL-2). MUC1 and MUC16 were overexpressed in tumor samples and showed differential distribution profiles. Serum MUC1 (CA15-3) measurements were elevated in all patients and significantly correlated with increased risk of death (P = 0.003). MUC1-specific IgM and IgG anitbodies were found in 92 and 50% of cases, respectively. Patients with progressive disease had higher mean anti-MUC1 IgG than responders at both early (P = 0.025) and late (P = 0.022) time points during IP IL-2 treatment. Anti-MUC1 IgM antibodies inversely correlated with overall survival at both early (P = 0.052) and late (P = 0.009) time points. In contrast to MUC1, neither soluble MUC16 nor MUC16-specific antibodies were significantly associated with clinical response or overall survival in this study. Increased serum MUC1 and high anti-MUC1 antibody levels are prognostic for poor clinical response and reduced overall survival in platinum-resistant or platinum-refractory ovarian cancer.

Restraint stress and stress hormones significantly impact T lymphocyte migration and function through specific alterations of the actin cytoskeleton.

Stress triggers complex response mechanisms designed to recognize and adapt to perturbations in homeostasis. The immune system is highly responsive to stress, although the complete mechanisms linking stress and immune mediators including T lymphocytes, are not fully understood. Stress exerts its effects on immune effectors through two primary pathways: the sympathetic-adrenal-medullary pathway, and the hypothalamic-pituitary-adrenal pathway which modulate adaptive immunity and lymphocyte migration. In this report we show that stress via release of stress hormones induces early T cell activation and greatly impacts the cytoskeleton by modulating numerous actin-regulating proteins. In particular, proteomic profiling revealed significant decreases in numerous key actin-binding proteins including moesin. Although confocal microscopy showed that moesin and actin were uniformly distributed on the surface of resting T cells, a remarkable polarization and redistribution of moesin and actin was observed following treatment with stress hormones with moesin localizing at the distal pole complex. In addition, the alteration in moesin localization and eventual decrease in expression were accompanied by a loss of CD43; a receptor involved in negatively regulating T cell activation. In conclusion, we have defined a novel molecular mechanism whereby stress hormones negatively impact T cell activation and migration through regulation of key cytoskeletal and plasma membrane factors.

High TGF-ß signature predicts immunotherapy resistance in gynecologic cancer patients treated with immune checkpoint inhibition.

Various immune signatures predictive of resistance to immune checkpoint inhibitors (ICI) have been described in multiple solid cancers, but still under-investigated in gynecological (GYN) cancer. For 49 GYN cancer patients included in our study, without transcriptome signature, immune-related toxicity was the only clinical predictor of ICI treatment response (p = 0.008). The objective clinical response was the only predictor of progression-free survival (ICI-PFS, p = 0.0008) and overall survival (ICI-OS, p = 0.01). Commonly used ICI marker PD-L1 expression negatively correlated with progression-free survival (ICI-PFS) (p = 0.0019). We performed transcriptome and signaling pathway enrichment analyses based on ICI treatment responses and the survival outcome, and further estimated immune cell abundance using 547 gene markers. Our data revealed that TGF-ß regulated signaling pathway was noted to play an important role in immunotherapy failure. Using our 6-genes TGF-ß score, we observed longer ICI-PFS associated with lower TGF-ß score (8.1 vs. 2.8 months, p = 0.046), which was especially more prominent in ovarian cancer (ICI-PFS 16.6 vs. 2.65 months, p = 0.0012). Further, abundant immunosuppressive cells like T-regulatory cells, eosinophils, and M2 macrophages were associated with shorter ICI-OS and correlated positively with CD274 and CTLA4 expressions. This study provides insight on the potential role of TGF-ß in mediating immunotherapy resistance and cross-talking to immunosuppressive environment in GYN cancer. The TGF-ß score, if validated in a larger cohort, can identify patients who likely to fail ICI and benefit from targeting this pathway to enhance the response to ICI.

Cancer-associated MSC drive tumor immune exclusion and resistance to immunotherapy, which can be overcome by Hedgehog inhibition.

We investigated the impact of cancer-associated mesenchymal stem cells (CA-MSCs) on ovarian tumor immunity. In patient samples, CA-MSC presence inversely correlates with the presence of intratumoral CD8+ T cells. Using an immune "hot" mouse ovarian cancer model, we found that CA-MSCs drive CD8+ T cell tumor immune exclusion and reduce response to anti­PD-L1 immune checkpoint inhibitor (ICI) via secretion of numerous chemokines (Ccl2, Cx3cl1, and Tgf-ß1), which recruit immune-suppressive CD14+Ly6C+Cx3cr1+ monocytic cells and polarize macrophages to an immune suppressive Ccr2hiF4/80+Cx3cr1+CD206+ phenotype. Both monocytes and macrophages express high levels of transforming growth factor ß­induced (Tgfbi) protein, which suppresses NK cell activity. Hedgehog inhibitor (HHi) therapy reversed CA-MSC effects, reducing myeloid cell presence and expression of Tgfbi, increasing intratumoral NK cell numbers, and restoring response to ICI therapy. Thus, CA-MSCs regulate antitumor immunity, and CA-MSC hedgehog signaling is an important target for cancer immunotherapy.

Complex carbohydrates are not removed during processing of glycoproteins by dendritic cells: processing of tumor antigen MUC1 glycopeptides for presentation to major histocompatibility complex class II-restricted T cells.

In contrast to protein antigens, processing of glycoproteins by dendritic cells (DCs) for presentation to T cells has not been well studied. We developed mouse T cell hybridomas to study processing and presentation of the tumor antigen MUC1 as a model glycoprotein. MUC1 is expressed on the surface as well as secreted by human adenocarcinomas. Circulating soluble MUC1 is available for uptake, processing, and presentation by DCs in vivo and better understanding of how that process functions in the case of glycosylated antigens may shed light on antitumor immune responses that could be initiated against this glycoprotein. We show that DCs endocytose MUC1 glycopeptides, transport them to acidic compartments, process them into smaller peptides, and present them on major histocompatability complex (MHC) class II molecules without removing the carbohydrates. Glycopeptides that are presented on DCs are recognized by T cells. This suggests that a much broader repertoire of T cells could be elicited against MUC1 and other glycoproteins than expected based only on their peptide sequences.