Levels Of Myeloid-derived Suppressor Cells Research Articles

IFNα and 5-Aza-2'-deoxycytidine combined with a dendritic-cell targeting DNA vaccine alter tumor immune cell infiltration in the B16F10 melanoma model.

DNA vaccines containing a fusion of the gene encoding chemokine MIP-3α (CCL20), the ligand for CCR6 on immature dendritic cells (DCs), to melanoma-associated antigen genes have enhanced anti-tumor immunity and efficacy compared to those lacking the chemokine gene. Previous work has shown that type-I interferon (IFNα or IFN) and 5-Aza-2'-deoxycytidine (5Aza) significantly enhance the therapeutic benefit of DNA vaccines as measured by reduced tumor burden and improved mouse survival. Here, we explored mouse intratumoral immune correlates underlying the therapeutic benefit of this combination regimen (vaccine, IFN, and 5Aza) as compared to vaccine alone and IFN and 5Aza without vaccine, focusing on chemokine mRNA expression by qRT-PCR and inflammatory cellular infiltration into the tumor microenvironment (TME) by flow cytometry and immunohistochemistry (IHC). The combination group significantly upregulated intratumoral mRNA expression of key immune infiltration chemokines XCL1 and CXCL10. Flow cytometric analyses of tumor suspensions exhibited greater tumor infiltration of CD8+ DCs, CCR7+ DCs, and NK cells in the combination group, as well as reduced levels of myeloid-derived suppressor cells (MDSCs) in vaccinated groups. The mice receiving combination therapy also had greater proportions of effector/memory T-cells (Tem), in addition to showing an enhanced infiltration of Tem and central memory CD8+ T-cells, (Tcm). Tem and Tcm populations both correlated with smaller tumor size. Immunohistochemical analysis of tumors confirmed that CD8+ cells were more abundant overall and especially in the tumor parenchyma with combination therapy. Efficient targeting of antigen to immature DCs with a chemokine-fusion vaccine offers a potential alternative approach to classic and dendritic cell-based vaccines. Combining this approach with IFNα and 5Aza treatments significantly improved vaccine efficacy. This treatment creates an environment of increased inflammatory chemokines that facilitates the trafficking of CD8+ DCs, NK cells, and CD8+ T-cells, especially memory cells, while reducing the number of MDSCs. Importantly, in the combination group, CD8+ cells were more able to penetrate the tumor mass in addition to being more numerous. Further analysis of the pathways engaged by our combination therapy is expected to provide additional insights into melanoma pathogenesis and facilitate the development of novel treatment strategies.

Alternative Chemotherapies: Angiotensin-Converting Enzyme Inhibitors Reduce Myeloid-Derived Suppressor Cells to Benefit Older Patients with Colorectal Cancer.

Older individuals are more likely to develop solid cancers, but at the same time are more sensitive to the side effects of chemotherapy. In addition, older adults are more likely to present with chronic diseases (comorbidities) and immunosenescence that may decrease immunosurveillance against cancer. Clinical outcomes for the older patient with cancer are different from the younger patient and require different research and treatment approaches. Thus, alternative therapeutic approaches tailored specifically to the older patients are required. Colorectal cancer (CRC) has a high incidence in older individuals and is the third leading cause of cancer death globally. Anti-hypertensives are used by a large proportion of older patients and some studies have pointed to a positive impact of angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB) on CRC outcomes. As we have previously shown in a mouse model, lung metastases express ACE and contain many infiltrating myeloid-derived suppressor cells (MDSC); particularly high levels of MDSC are also present in the blood of older patients with CRC and other cancers, and are associated with disease severity. In this Commentary, we hypothesize that one mechanism responsible for the positive impact of ACEi or ARB on the outcome of CRC is the modulation of myeloid cells contributing to their maturation to non-suppressive neutrophils/monocytes and diverting them away from retaining an immature MDSC phenotype.

Abstract PR002: A pilot study of a MUC1 vaccine in current and former smokers at high risk for lung cancer

Abstract Background: Smoking is the most common etiology for lung cancer and smoking cessation does not eliminate the risk. An emerging area of interest for risk reduction is immunoprevention. MUC1 glycoprotein is aberrantly expressed in adenocarcinomas, including lung cancer and their premalignant lesions. MUC1 vaccine in the premalignant or high-risk setting may be effective in halting neoplastic development and progression. Trial design: Through the NCI-funded Cancer Prevention Network (CPN), we conducted a two-center pilot trial to evaluate immunogenicity of the MUC1 vaccine (assessed at 12 weeks), and safety (assessed at up to 24 weeks) in current and former heavy smokers. 87 participants were screened in order to have at least 40 evaluable for baseline and 12-week immunogenicity assessments. Smoking history of ≥30 pack-years and either current (still smoking or quit < 1 year prior to pre-registration) or former smoker (quit 1-15 years prior to pre-registration); ages 55-80 years; ECOG performance status ≤1; CT scan of the chest done ≤ 6 months prior to pre-registration showing either negative findings (no nodules) or solid or part-solid nodules < 6 mm in size (consistent with < 1% probability of malignancy, Lung-RADs Version 1.0). Exclusion criteria were standard for lung cancer screening. Methods: MUC1 peptide plus polyICLC adjuvant (Hiltonol) vaccine was given at week 0, 2 and 10. Blood was collected for safety tests and immune assays pre and 2 weeks post each vaccine, and at week 24. Anti-MUC1 IgG titer was evaluated by ELISA. Based on previous studies of this vaccine, 40 evaluable participants would provide 96% power to detect immune response rate of 15% versus 40%, using a 2-sided test of proportions with type I error rate of 0.05. PBMC were assayed for the presence of regulatory T cells (Treg) and myeloid derived suppressor cells (MDSC) (secondary endpoint). Circulating levels of inflammatory cytokines and hsCRP were evaluated using commercially available tests (exploratory endpoint). AEs and toxicities were monitored for up to 24 weeks from the first vaccine. Results: 87 individuals were screened and 50 registered. 45 completed the study, 26 current and 19 former smokers (time since last smoked: average 7.8 years; 11 months -13 years). The vaccine was well-tolerated with injection site reactions being the most common AE. Immune response to the vaccine was lower than expected, with 2 current and 2 former smokers developing anti-MUC1 IgG titers ≥2 fold higher at week 12 over baseline (10%). We found high circulating levels of MDSCs in PBMC of both current and former smokers and very low or no serum cytokines. Conclusions: A preventative vaccine trial was feasible in individuals at high risk for lung cancer. However, we discovered a high level of immune suppression, previously documented only in advanced lung cancer. Mitigating the development of lung cancer in heavy smokers through vaccine administration may be limited by related immunosuppression. Citation Format: Olivera J. Finn, Julie Ward, Tami Krpata, Samantha Fatis, John McKolanis, Jia Xue, Pamela Beatty, Camille Jacqueline, Sharon Kaufman, Colleen Akerley, April Felt, Karrie Fursa, Anne Holland, Liz S. Ambulay, Nathan Foster, Ryan McMurray, Carrie Strand, Andres M. Salazar, Lisa Bengtson, Eva Szabo, Paul Limburg, Malgorzata Wojtowicz, David E. Midthun, Arjun Pennathur. A pilot study of a MUC1 vaccine in current and former smokers at high risk for lung cancer. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr PR002.

Alpha-Fetoprotein: A Revolutionary Anti-Cancer Drug

Alpha-fetoprotein is an oncofetal protein the embryo produces during fetal development. The protein serves two critical functions simultaneously: it delivers nutrients to growing embryo cells and immature myeloid-derived suppressor cells, so the mother’s immune system doesn’t attack the embryo. The protein is present in minuscule amounts in adults and elevated alpha-fetoprotein levels serve as pregnancy or tumor markers. Exogenous alpha-fetoprotein has a new application as an immunotherapy drug. It can deliver drugs in a natural shuttle manner to myeloid-derived suppressor cells and stimulate them to calm the hyperactive immune response during many physiological and pathological conditions. On the other hand, alpha-fetoprotein loaded with toxins kills myeloid-derived suppressor cells and unleashes natural killer cells and cytotoxic lymphocytes to erase cancer. Most cancers have cells that specifically bind alpha-fetoprotein, and this protein targets chemotherapy to them also. So, alpha-fetoprotein with toxins combines both potent cancer immunotherapy and targeted chemotherapy activities. Alpha-fetoprotein can be chemically conjugated with or bind toxins non-covalently. Both preparations have demonstrated superior efficacy and safety compared to chemotherapy alone. Alpha-fetoprotein-toxin immuno/chemotherapy is not personalized. There is no need to preselect patients for cancer treatments as they have elevated myeloid-derived suppressor cell levels. The anti-cancer efficacy of porcine alpha-fetoprotein non-covalent complexes with selected toxins administered orally is a remarkable discovery that needs research. Cancer treatment and prevention are different issues, and they could need different approaches. Alpha-fetoprotein administration with drugs or toxins could be as effective in early cancer and metastasis prevention as mifepristone pills in pregnancy prevention.

Anlotinib reduces the suppressive capacity of monocytic myeloid-derived suppressor cells and potentiates the immune microenvironment normalization window in a mouse lung cancer model.

By exploring the effects of an antiangiogenic small molecule drug named anlotinib on the levels of myeloid-derived suppressor cells (MDSCs) in a mouse xenograft model of lung cancer, the role of anti-angiogenesis in remodeling the immune microenvironment was discussed. In addition, the impact of anlotinib on the normalization of the immune microenvironment and time window was examined, providing a theoretical basis for the optimization of clinical strategies applying anlotinib combined with PD-1 inhibitors. On the basis of the LLC mouse xenograft model, MDSCs and MDSCs + immune microenvironment were examined in tissues, respectively, according to different samples. The former observation included the control (group A) and anlotinib monotherapy (group B) groups; the latter also included the control (group C) and anlotinib monotherapy (group D) groups. The levels of MDSCs in peripheral blood at different time points were analyzed by flow cytometry, and the levels of MDSCs in tissue samples at different time points were evaluated by immunofluorescence and immunohistochemistry. The volumes of subcutaneous xenografts were significantly smaller in the anlotinib treatment group compared with the control group ( P < 0.005). Flow cytometry showed that compared with the control group, the intratumoral percentages of total MDSCs ( P < 0.01) and mononuclear-MDSCs ( P < 0.05) were significantly decreased on days 3 and 17 after anlotinib treatment in peripheral blood samples; however, there was no significant difference in granulocytic-MDSCs changes between the experimental and control groups. Immunofluorescence showed that the levels of MDSCs in both the experimental and control groups reached the lowest points 10 days after drug administration, and were significantly lower in the experimental group than in the control group ( P < 0.05). Anlotinib reduces the levels of MDSCs in the mouse xenograft model of lung cancer, with the characteristics of time window. This study provides a basis for further exploring strategies for anti-angiogenic treatment combined with immunotherapy in lung cancer based on time-window dosing.

Pembrolizumab in combination with gemcitabine for patients with HER2-negative advanced breast cancer: GEICAM/2015–04 (PANGEA-Breast) study

BackgroundWe evaluated a new chemoimmunotherapy combination based on the anti-PD1 monoclonal antibody pembrolizumab and the pyrimidine antimetabolite gemcitabine in HER2- advanced breast cancer (ABC) patients previously treated in the advanced setting, in order to explore a potential synergism that could eventually obtain long term benefit in these patients.MethodsHER2-negative ABC patients received 21-day cycles of pembrolizumab 200 mg (day 1) and gemcitabine (days 1 and 8). A run-in-phase (6 + 6 design) was planned with two dose levels (DL) of gemcitabine (1,250 mg/m2 [DL0]; 1,000 mg/m2 [DL1]) to determine the recommended phase II dose (RP2D). The primary objective was objective response rate (ORR). Tumor infiltrating lymphocytes (TILs) density and PD-L1 expression in tumors and myeloid-derived suppressor cells (MDSCs) levels in peripheral blood were analyzed.ResultsFourteen patients were treated with DL0, resulting in RP2D. Thirty-six patients were evaluated during the first stage of Simon’s design. Recruitment was stopped as statistical assumptions were not met. The median age was 52; 21 (58%) patients had triple-negative disease, 28 (78%) visceral involvement, and 27 (75%) ≥ 2 metastatic locations. Progression disease was observed in 29 patients. ORR was 15% (95% CI, 5–32). Eight patients were treated ≥ 6 months before progression. Fourteen patients reported grade ≥ 3 treatment-related adverse events. Due to the small sample size, we did not find any clear association between immune tumor biomarkers and treatment efficacy that could identify a subgroup with higher probability of response or better survival. However, patients that experienced a clinical benefit showed decreased MDSCs levels in peripheral blood along the treatment.ConclusionPembrolizumab 200 mg and gemcitabine 1,250 mg/m2 were considered as RP2D. The objective of ORR was not met; however, 22% patients were on treatment for ≥ 6 months. ABC patients that could benefit of chemoimmunotherapy strategies must be carefully selected by robust and validated biomarkers. In our heavily pretreated population, TILs, PD-L1 expression and MDSCs levels could not identify a subgroup of patients for whom the combination of gemcitabine and pembrolizumab would induce long term benefit.Trial registrationClinicalTrials.gov and EudraCT (NCT03025880 and 2016–001,779-54, respectively). Registration dates: 20/01/2017 and 18/11/2016, respectively.

Abstract IA016: Lessons learned from clinical trials of MUC1 peptide vaccines for cancer prevention

Abstract We report on three trials of a MUC1 peptide vaccine for cancer prevention. Two trials were pilot studies evaluating vaccine immunogenicity and safety. One was in subjects with advanced colon adenomas, and the other in smokers at risk for lung cancer. The third trial was a multi-center, randomized placebo-controlled trial in subjects with advanced adenoma that included an assessment of the clinical efficacy of the vaccine to prevent recurrent adenoma. All trials successfully recruited their full complement of participants and the vaccine was well tolerated with no safety concerns. The response rate in the colon adenoma trials was 43% in the pilot study and 25% in the placebo- controlled multicenter trial. Only 10% of smokers responded to the vaccine. Higher levels of circulating myeloid derived suppressor cells (MDSC) were consistently associated with the lack of an immune response. This suggests that even in pre-malignancy immunosuppressive tendencies can impair vaccine immunogenicity. Responders to the vaccine demonstrated immune memory at one year. In the multicenter adenoma trial that evaluated the efficacy of the vaccine on adenoma recurrence, immune responders demonstrated an association with a reduced rate of adenoma recurrence. In future studies, patient selection based on circulating MDSC levels, or concomitant use of agents to counter MDSC immunosuppressive function or otherwise improve T cell function, should be considered. Citation Format: Robert E. Schoen. Lessons learned from clinical trials of MUC1 peptide vaccines for cancer prevention [abstract]. In: Proceedings of the Second Biennial NCI Meeting: Translational Advances in Cancer Prevention Agent Development (TACPAD); 2022 Sep 7-9. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_2): Abstract nr IA016.

Circulating myeloid-derived suppressor cells and survival in prostate cancer patients: systematic review and meta-analysis.

Immunotherapy has not achieved improvement of survival in prostate cancer patients. Myeloid-derived suppressor cells (MDSCs) in tumor microenvironment can hamper its efficacy. Some preclinical studies explored the role of MDSCs in prostate cancer development. We aimed to verify the availability of studies exploring the prognostic effect of circulating MDSCs in prostate cancer patients. We systematically selected studies for a meta-analysis, which compares survival between prostate cancer patients with high vs low circulating MDSC levels. We extracted or calculated hazard ratios (HRs) and relative 95% confidence intervals (CIs) in terms of overall survival (OS) from selected studies. We calculated the pooled HR and relative 95% CIs and estimated publication bias. Among 133 studies retrieved from search on Pubmed, 5 eligible studies (236 prostate cancer patients) met inclusion criteria. High circulating MDSC levels are associated with a worse OS (HR = 2.19; 95%CI = 1.51-3.17). Heterogeneity was not significant (I2 = 0%; p = 0.64). Publication bias was also not significant (Egger's test, p = 0.09). High levels of circulating MDSCs induce a worse OS in prostate cancer patients than in those with low levels. This finding supports the importance of MDSC detection and targeting also in prostate cancer patients.

Immune Signature of Pembrolizumab Plus Gemcitabine, Vinorelbine, and Liposomal Doxorubicin As Second-Line Therapy for Relapsed or Refractory Classical Hodgkin Lymphoma

Introduction: In our phase II study (Moskowitz AJ et al, JCO 2021), pembrolizumab plus gemcitabine, vinorelbine, and liposomal doxorubicin (P-GVD) was found to be highly effective as salvage for patients (pts) with relapsed or refractory (R/R) classic Hodgkin lymphoma (cHL) proceeding to high dose therapy and autologous hematopoietic cell transplantation (AHCT). We present analyses assessing immunologic changes associated with P-GVD treatment as well as updated clinical outcome. Methods: Transplant eligible pts with R/R cHL following failure of 1-line of therapy were eligible. Treatment consisted of 2 to 4 cycles of P-GVD followed by AHCT. Peripheral blood samples were collected at baseline, after 2 cycles of P-GVD, before AHCT, 3 and 9 months after AHCT. Peripheral blood was analyzed for serum thymus and activation-regulated chemokine (TARC) and immune cell subsets. TARC was measured by enzyme-linked immunosorbent assay. Immune cell subsets, including T-cells and myeloid-derived suppressor cells (MDSC), were measured by multi-parametric flow cytometry (FC). Metabolic tumor volume (MTV) was evaluated at baseline. Changes in MDSC and TARC levels were assessed using Wilcoxon rank sum and Friedman tests, respectively. Correlations between MTV and either TARC or MDSC were assessed using Pearson's R. Results: Of 38 evaluable pts, the complete response (CR) rate after 2 or 4 cycles of P-GVD was 95%. Two pts declined AHCT and 36 proceeded to AHCT. After a median follow-up of 30 months (range: 2-43), only 1 pt experienced disease progression 23 months after AHCT. The estimated 30-month progression-free survival (PFS) is 96%. The median baseline MTV value was 37 cm3 (range 4- 845). 36/38 and 27/38 pts had sufficient correlative samples to perform analysis for TARC and MDSC analysis, respectively. The median baseline TARC level was 526 pg/mL (range: 12-4017). TARC levels decreased significantly after 2 cycles of P-GVD (p < 0.001) and increased post-AHCT. Circulating MDSCs were 0.05% of total mononuclear cells (range: 0.003-0.59%) and significantly increased after 2 cycles of P-GVD (p<0.001). Higher baseline TARC and circulating MDSC levels correlated with higher baseline MTV (r=0.45, 95% CI: 0.11-0.70, p<0.01 and r=0.46, 95%CI 0.03-0.76, p=0.03, respectively). High-dimensional analysis of FC data revealed several distinct immune clusters (Figure 1), of which non-proliferating PD-1+ CD4+ T-cells decreased most significantly following treatment (Figure 2). Additional markers (ICOS, CTLA-4, LAG-3, FOXP3) of immune exhaustion showed only a mild decrease over the treatment course. Conclusions: After a median of 30-months follow-up, second-line P-GVD continues to be associated with durable remissions after AHCT. These analyses provide insights into key immune changes associated with chemoimmunotherapy in HL. Baseline TARC correlated with baseline MTV and was significantly lower after P-GVD, illustrating its role as a marker of tumor bulk. The subsequent rise in serum TARC post AHCT suggests immune reconstitution of TARC-secreting cells. Higher circulating levels of MDSCs correlated with baseline MTV, which may reflect an association between immune suppression and tumor bulk. MDSC levels unexpectedly increased after P-GVD, indicating that a rise in MDSCs after treatment may not necessarily predict for poor outcomes. Ongoing single-cell RNA sequencing analysis of peripheral blood mononuclear cells (PBMC) may provide further understanding into immune dynamics associated with P-GVD treatment. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Role of Circulating Myeloid-Derived Suppressor Cell (MDSC) in Hodgkin Lymphoma (HL) Progression: Highlighting Clinical Relevance

Introduction. About 15-25% of patients with HL have primary refractory disease or relapse after the first line of therapy and about half of them diagnosed chemosensitivity after transplantation. In the attempt to find a peripheral blood biological marker that could mirror the dysregulated microenvironment of HL, we analyzed the number of myeloid-derived suppressor cells (MDSC) and its correlation with clinical variables and response to therapy. Methods. 52 primary HL patients, (median age: 40, range: 19-61 years; male: 21, female: 31), were included in the study since April, 2018. 63.5% and 36.5% of patients have been diagnosed with early and advanced stages of HL, respectively, and received the ABVD or BEACOPP (14/esc) as a 1st-line treatment regimen. We have also used a routine protocol of metabolic PET assessment according to Deauville criteria of treatment response. Results. 82.6% (43/52) of patients achieved remission (CR/PR) during the follow-up period (median timeline: 25 months). We recorded a disease progression in 6/52 (11.5%) patients during and after the 1st line therapy, (median time to relapse - 8 months). We observed that the level of E-MDSC in patients with HL before treatment is twelve times higher than in healthy control group (24% vs 2 % respectively, p=0.02). Also, the E-MDSC count increases significantly with age of HL patient (with the highest levels in patients over 40 y.o., p=0.008) and with the stage of the disease. Thus patients with advanced stages (III-IV) of HL have increased % of circulating E-MDSC compared to early stages (1A-2B) of disease (p=0.07) . We also found the significant correlation between increased level of MDSC during the treatment and the presence of 4 or more risk factors by IPS (p=0.03). Patients with negative PET results (interim and EOT) had a significantly lower percent of E-MDSC in peripheral blood during and in the end of treatment compare to positive PET patients (interim MDSC: 14% vs 36%, p=0.03; EOT MDSC: 12% vs 42%, p=0.0007, respectively). Patients with CR also had increased number of T and NK-T cells compared to pre-treatment numbers (p=0.05), which all together indicates the activation of anti-tumor immune response. Conclusion. Increased level of circulating E-MDSC is associated with age, advanced stage of HL, presence of 4 or more IPS risk factors and poor clinical outcome. Evaluation of MDSC levels in peripheral blood can be used as additional prognostic marker for early clinical outcome assessment. The discovery of new prognostic factors will improve the individualized approach to the treatment of patients and reduce the risk of disease recurrence.

Genomic landscape of the immunogenicity regulation in skin melanomas with diverse tumor mutation burden.

Skin melanoma cells are tightly interconnected with their tumor microenvironment (TME), which influences their initiation, progression, and sensitivity/resistance to therapeutic interventions. An immune-active TME favors patient response to immune checkpoint inhibition (ICI), but not all patients respond to therapy. Here, we assessed differential gene expression in primary and metastatic tumors from the TCGA-SKCM dataset, compared to normal skin samples from the GTEx project and validated key findings across 4 independent GEO datasets, as well as using immunohistochemistry in independent patient cohorts. We focused our attention on examining the expression of various immune receptors, immune-cell fractions, immune-related signatures and mutational signatures across cutaneous melanomas with diverse tumor mutation burdens (TMB). Globally, the expression of most immunoreceptors correlated with patient survival, but did not differ between TMBhigh and TMBlow tumors. Melanomas were enriched in "naive T-cell", "effector memory T-cell", "exhausted T-cell", "resting Treg T-cell" and "Th1-like" signatures, irrespective of their BRAF, NF1 or RAS mutational status. Somatic mutations in IDO1 and HLA-DRA were frequent and could be involved in hindering patient response to ICI therapies. We finally analyzed transcriptome profiles of ICI-treated patients and associated their response with high levels of IFNγ, Merck18, CD274, CD8, and low levels of myeloid-derived suppressor cells (MDSCs), cancer-associated fibroblasts (CAFs) and M2 macrophages, irrespective of their TMB status. Overall, our findings highlight the importance of pre-existing T-cell immunity in ICI therapeutic outcomes in skin melanoma and suggest that TMBlow patients could also benefit from such therapies.

Current use of T-cell depleting polyclonal antibodies in liver transplant recipients: Results of a nationwide French survey

Shikonin (SHK) has multifaceted physiological functions, including antitumor, anti-inflammatory, and antimicrobial effects. Recently, SHK has been shown to affect immune responses; however, its detailed immune modulatory function in vivo remains unclear. In this study, we demonstrated that SHK not only inhibited T cell proliferation in vitro, but also intensively inhibited thymopoiesis and eliminated CD4/CD8 double-positive thymic progenitor cells in vivo. Treatment of mice with SHK resulted in immune profile alterations, which promoted myelosis in the bone marrow and increased inhibitory immune cells in central immune organs. A decrease in T cells and B cells was observed in the spleen. Using a murine allogenic skin transplantation model, we revealed that short-term treatment of recipients with SHK significantly inhibited skin graft rejection, in which the levels of myeloid-derived suppressor cells (MDSC) were markedly increased. Taken together, our study suggests that SHK can efficiently eliminate proliferating T cells and inhibit thymopoiesis while promoting the generation of MDSC, indicating its potential role in alleviating immune responses in allogeneic organ/cell transplantation.

Identification of Essential Tumor-Infiltrating Immune Cells and Relevant Genes in Left-Sided and Right-Sided Colon Cancers.

Simple SummaryDifferences in oncogenes between left-sided colon cancer and right-sided colon cancer have been reported in-depth. Tumor-infiltrating immune cells and relevant genes between left-sided and right-sided colon cancers are unclear. Bioinformatic analysis was used to identify these hub immune cells and relevant genes. Colon cancer outcomes are associated with changes in MDSC infiltration, and therefore LCP1, ITGB2, and IKZF1 may be novel targets for immunotherapy.Backgrounds: Colorectal cancer is the third most prevalent cancer worldwide. A right-sided colon cancer patient typically has a worse prognosis than one who has a left-sided colon cancer. There is an unclear understanding of how left-sided colon cancer differs from right-sided colon cancer in tumor-infiltrating immune cells (TIICs) and relevant genes. Methods: The Cancer Genome Atlas provided RNA-seq data and clinical information regarding colon adenocarcinoma. We conducted a single-sample gene set enrichment analysis (ssGSEA) to quantify the level of 24 immune cells infiltrating the tissues. Based on an analysis of univariate Cox regression, immune cell types associated with survival were identified. Weighted gene co-expression network analysis (WGCNA) was used to identify hub genes related to location and critical immune cells. Based on the Search Tool for the Retrieval of Interacting Genes (STRING), interaction potential was predicted among the hub genes. Hub genes that influence outcomes through immune infiltration were identified using the least absolute shrinkage and selection operator (LASSO). Then, we used the TISIDB database (a repository portal for tumor–immune system interactions) to validate the correlation between hub genes and immune cell infiltration. Finally, immunohistochemical assays were conducted to determine the levels of proteins expressed by critical TIICs and cancer cells. Results: Colon cancers on the right side of the body had higher levels of myeloid-derived suppressor cells (MDSCs) than on the left side. There were three key genes: LCP1, ITGB2, and IKZF1. It was found that their expression was linked to poor prognosis and an increased level of MDSC infiltration. An immunohistochemical study confirmed these findings. Conclusions: There is a higher rate of MDSC infiltration in right-sided colon cancer when compared with left-sided colon cancer. COAD outcomes are associated with changes in MDSC infiltration, and therefore LCP1, ITGB2, and IKZF1 may be novel targets for immunotherapy.

1253P Safety and efficacy of Wnt inhibition with a DKK1 inhibitor, DKN-01, in combination with atezolizumab in patients with advanced oesophagogastric adenocarcinoma: Phase IIa results of the WAKING trial

Immune checkpoint inhibitor (ICI) monotherapy has limited efficacy in patients (pts) with mismatch repair proficient (MMRp) oesophagogastric adenocarcinoma (OGA). Dickkopf-1 (DKK1) modulates Wnt/β-Catenin signaling and promotes a T-cell excluded or ‘immune desert’ tumour microenvironment (TME). DKN-01, a DKK1 neutralising antibody, can favourably reprogram the TME by reducing levels of myeloid-derived suppressor cells (MDSCs) and increasing entry of effector T-cells and may improve responses when added to ICI monotherapy. This phase IIa study (3+3 design) evaluated the safety and efficacy of DKN-01 (300mg/600mg) and atezolizumab (840mg) given intravenously q2W in pts with pre-treated, anti PD1/PDL1 naïve, MMRp advanced OGA. The primary endpoint was to establish the safety, tolerability, and recommended phase II dose (RP2D) for the efficacy phase. Safety, efficacy, and translational analyses (including intratumoural DKK1/PD-L1, peripheral MDSC and NK cell populations, TCR diversity analysis, tumour genomics and stool microbiome) are ongoing. Eleven pts were treated on study (5 pts at DKN-01 300mg, 6 at 600mg). Eight pts completed the DLT period (3 at 300mg, 5 at 600mg) and were therefore evaluated for the safety endpoint. No dose limiting toxicities were observed. Of the 11 treated pts, 10 (90.9%) experienced at least one treatment-related AE (TRAE). The most common TRAEs (experienced by ≥ 2 pts) were fatigue (36%), anaemia (18%), hypothyroidism (18%), diarrhoea (18%) and pain (18%). One pt experienced G3 urticaria and 1 experienced an SAE of G2 pneumonitis, both were treatment related. Of the 8 pts evaluated for the safety endpoint, 1 pt (12.5%) had PR and 4 pts (50%) had SD as their best response. No clear trend between peripheral MDSC levels at baseline and during treatment have yet been observed. Additional biomarker work is ongoing. DKN-01 plus atezolizumab has a manageable safety profile with no new safety signals in pts with advanced OGA. DKN-01 600mg plus atezolizumab 840mg q2W was the RP2D taken through to the ongoing expansion phase to confirm efficacy.

A polysaccharide from native Curcuma kwangsiensis and its mechanism of reversing MDSC-induced suppressive function

A purified polysaccharide nCKAP-2 was prepared from Curcuma kwangsiensis and characterized. Structural analyses revealed that nCKAP-2 contains a high-branched arabinan composed of mono-substituted (O-5, 17.07 %) and di-substituted (O-2,5, 16.67 %) (1 → 3)-α-Araf residues. Bioactive test showed that nCKAP-2 significantly reversed the suppression function of myeloid-derived suppressor cells (MDSCs) on T cells. Further study revealed that treatment of MDSCs with nCKAP-2 could induce apoptotic cell death at the G0/G1 phase via the intrinsic pathway as suggested from the up-regulation of cleaved caspase 3 and 9, cleaved PARP, and Bax and the down-regulation of Bcl-xl. This apoptotic process was mainly mediated by the TLR4-NF-κB signaling pathway. Additionally, the down-regulation of ROS level of MDSCs after nCKAP-2 treatment involved in this process. Summarily, we explain how nCKAP-2 reverses the MDSC-induced suppressive function on T cells, and provide a scientific basis for the clinical application and development of C. kwangsiensis.

Shikonin impairs T lymphocyte proliferation and thymopoiesis while it may increase myeloid-derived suppressor cells to alleviate immune responses

Shikonin (SHK) has multifaceted physiological functions, including antitumor, anti-inflammatory, and antimicrobial effects. Recently, SHK has been shown to affect immune responses; however, its detailed immune modulatory function in vivo remains unclear. In this study, we demonstrated that SHK not only inhibited T cell proliferation in vitro, but also intensively inhibited thymopoiesis and eliminated CD4/CD8 double-positive thymic progenitor cells in vivo. Treatment of mice with SHK resulted in immune profile alterations, which promoted myelosis in the bone marrow and increased inhibitory immune cells in central immune organs. A decrease in T cells and B cells was observed in the spleen. Using a murine allogenic skin transplantation model, we revealed that short-term treatment of recipients with SHK significantly inhibited skin graft rejection, in which the levels of myeloid-derived suppressor cells (MDSC) were markedly increased. Taken together, our study suggests that SHK can efficiently eliminate proliferating T cells and inhibit thymopoiesis while promoting the generation of MDSC, indicating its potential role in alleviating immune responses in allogeneic organ/cell transplantation.

Prospective Evaluation of Immune Activation Associated with Response to Radioembolization Assessed with PET/CT in Women with Breast Cancer Liver Metastasis.

Background The impact of transarterial radioembolization (TARE) of breast cancer liver metastasis (BCLM) on antitumor immunity is unknown, which hinders the optimal selection of candidates for TARE. Purpose To determine whether response to TARE at PET/CT in participants with BCLM is associated with specific immune markers (cytokines and immune cell populations). Materials and Methods This prospective pilot study enrolled 23 women with BCLM who planned to undergo TARE (June 2018 to February 2020). Peripheral blood and liver tumor biopsies were collected at baseline and 1-2 months after TARE. Monocyte, myeloid-derived suppressor cell (MDSC), interleukin (IL), and tumor-infiltrating lymphocyte (TIL) levels were assessed with use of gene expression studies and flow cytometry, and immune checkpoint and cell surface marker levels with immunohistochemistry. Modified PET Response Criteria in Solid Tumors was used to determine complete response (CR) in treated tissue. After log-transformation, immune marker levels before and after TARE were compared using paired t tests. Association with CR was assessed with Wilcoxon rank-sum or unpaired t tests. Results Twenty women were included. After TARE, peripheral IL-6 (geometric mean, 1.0 vs 1.6 pg/mL; P = .02), IL-10 (0.2 vs 0.4 pg/mL; P = .001), and IL-15 (1.9 vs 2.4 pg/mL; P = .01) increased. In biopsy tissue, lymphocyte activation gene 3-positive CD4+ TILs (15% vs 31%; P < .001) increased. Eight of 20 participants (40% [exact 95% CI: 19, 64]) achieved CR. Participants with CR had lower baseline peripheral monocytes (10% vs 29%; P < .001) and MDSCs (1% vs 5%; P < .001) and higher programmed cell death protein (PD) 1-positive CD4+ TILs (59% vs 26%; P = .006) at flow cytometry and higher PD-1+ staining in tumor (2% vs 1%; P = .046). Conclusion Complete response to transarterial radioembolization was associated with lower baseline cytokine, monocyte, and myeloid-derived suppressor cell levels and higher programmed cell death protein 1-positive tumor-infiltrating lymphocyte levels. © RSNA, 2022 Online supplemental material is available for this article.

Clinical and molecular characteristics of AMBITION patients who received olaparib plus cediranib or olaparib plus durvalumab for homologous recombination repair mutated, platinum-resistant ovarian cancer (KGOG 3045) (032)

Objectives: AMBITION is a multi-center, open-label, five-arm, uncontrolled, umbrella trial in platinum-resistant ovarian cancer patients (NCT03699449). Here, we present an exploratory analysis of clinical and molecular characteristics associated with the benefit of two olaparib-based regimens in the homologous recombination repair (HRR) gene mutation cohort. Methods: Between December 2018 and October 2020, 30 patients who had mutations in HRR genes were randomized, and received either olaparib 200mg bid + cediranib 30mg QD (arm 1; n=16) or olaparib 300mg bid + durvalumab 1500mg q4w (arm 2; n=14). From the pre-treatment biopsy (n=22) and archival (n=8) tumor samples, next-generation whole-exome and whole-transcriptomic sequencing were conducted. We also evaluated tumor immunologic signatures, including the PD-L1 (SP263) assay and tumor-infiltrating lymphocytes (TILs). Clinical and molecular features were compared between responders and non-responders. Results: Arms 1 and 2 showed an acceptable objective response rate at 50.0% and 42.9%, respectively. The responders (n=14) had 12.4 months of a median duration of response. Overall, no differences in serum CA-125 levels, ECOG performance status, histologic subtype, prior lines of therapy, and last treatment-free interval were observed between the responders and non-responders. Intratumoral TILs and stromal TILs were also similar between the responders and non-responders. While all responders had BRCA1/2 mutations, 54.5% of non-responders had BRCA1/2 mutations. DNA damage repair pathways were enriched in the responders. Especially, enrichment of DNA mismatch repair and nucleotide excision repair pathways were associated with prolonged progression-free survival (PFS). In arm 1, cell cycle pathway enrichment significantly improved PFS (p=0.006), but PD-L1 expression did not. In arm 2, patients with PD-L1 ≥1% of tumor cells showed significantly better PFS than those with PD-L1 <1% (p=0.027), and the responders had a significantly higher level of myeloid-derived suppressor cell recruiting score than the non-responders (p=0.041). Objectives: AMBITION is a multi-center, open-label, five-arm, uncontrolled, umbrella trial in platinum-resistant ovarian cancer patients (NCT03699449). Here, we present an exploratory analysis of clinical and molecular characteristics associated with the benefit of two olaparib-based regimens in the homologous recombination repair (HRR) gene mutation cohort. Methods: Between December 2018 and October 2020, 30 patients who had mutations in HRR genes were randomized, and received either olaparib 200mg bid + cediranib 30mg QD (arm 1; n=16) or olaparib 300mg bid + durvalumab 1500mg q4w (arm 2; n=14). From the pre-treatment biopsy (n=22) and archival (n=8) tumor samples, next-generation whole-exome and whole-transcriptomic sequencing were conducted. We also evaluated tumor immunologic signatures, including the PD-L1 (SP263) assay and tumor-infiltrating lymphocytes (TILs). Clinical and molecular features were compared between responders and non-responders. Results: Arms 1 and 2 showed an acceptable objective response rate at 50.0% and 42.9%, respectively. The responders (n=14) had 12.4 months of a median duration of response. Overall, no differences in serum CA-125 levels, ECOG performance status, histologic subtype, prior lines of therapy, and last treatment-free interval were observed between the responders and non-responders. Intratumoral TILs and stromal TILs were also similar between the responders and non-responders. While all responders had BRCA1/2 mutations, 54.5% of non-responders had BRCA1/2 mutations. DNA damage repair pathways were enriched in the responders. Especially, enrichment of DNA mismatch repair and nucleotide excision repair pathways were associated with prolonged progression-free survival (PFS). In arm 1, cell cycle pathway enrichment significantly improved PFS (p=0.006), but PD-L1 expression did not. In arm 2, patients with PD-L1 ≥1% of tumor cells showed significantly better PFS than those with PD-L1 <1% (p=0.027), and the responders had a significantly higher level of myeloid-derived suppressor cell recruiting score than the non-responders (p=0.041).

P-421 Increased myeloid-derived suppressor cells in women with recurrent miscarriage and recurrent implantation failure

Abstract Study question We sought to explore the levels of myeloid-derived suppressor cells (MDSCs) in women experiencing recurrent miscarriage (RM) or recurrent implantation failure (RIF) Summary answer MDSCs were significantly expanded in RM patients with respect to fertile healthy women (p = 0.03, 8.25 vs 7.00). What is known already RM and RIF are two distinct disorders that can be associated with a baseline pro-inflammatory state. Different surrogate inflammatory biomarkers have been associated with these disorders in a subgroup of patients, including expanded cytotoxic NK cells, increased pro-inflammatory cytokines or reduced regulatory T cells (TReg). MDSCs are a heterogeneous population of leukocytes, known for their capacity to modulate immune responses. The immunosuppressive function of MDSC in cancer has been well established, while a controversial role in autoimmune diseases has been reported. Typically, there are two major groups of MDSCs in humans: granulocytic/polymorphonuclear MDSCs (PMN-MDSCs) and monocytic MDSCs (M-MDSCs). Study design, size, duration A cross-sectional study to evaluate the levels of MDSCs in women with RM and RIF consecutively referred to our Reproductive Immunology Unit. 55 patients and 23 healthy women were evaluated from 2021 to 2022. RM was defined as the loss of two or more pregnancies and not necessarily consecutive. RIF was defined as the failure to achieve a clinical pregnancy after transferring at least four good-quality embryos. Participants/materials, setting, methods A full fertility screening was performed for all women and their partners as part of routine care. A group of healthy non-pregnant women up to 45 years old with two or more children (proven fertility) and no spontaneous miscarriage was used as control group. Freshly collected blood samples were analyzed by multiparametric flow cytometry using a BD FACS CANTO II. Peripheral blood M-MDSCs were characterized based on HLA-DR, CD14, CD33 and CD45 expression. Main results and the role of chance In this study, we evaluated 55 women, 35 that fulfilled RM criteria and 20 with RIF. In addition, a group of 23 non-pregnant fertile women was included as a control group. We characterized MDSCs as CD14+CD33+CD45+HLA-DR-/LOW, according to previous reports. We observed a significant expansion of peripheral blood MDSCs in RM group compared to the control group (8.25% [6.62-11.9] vs 7.05% [6-7.8], p = 0.03) and RIF group showed a similar increasing trend compared to controls (8.6% [5.65-12.35] vs 7.05% [6-7.8], p = 0.09). We performed ROC curves analysis to evaluate the predictive power. We established an optimal cut-off level of 8.3% in RM group, with a sensitivity of 50% and a specificity of 86.96%. Moreover, women with more than 8.3% had a higher probability of presenting RM compared to the control group (OR: 6.66; CI: 1.68-26.46). MDSCs are characterized by their ability to exert a potent immunosuppressive function. However, recent investigations have shown that MDSCs could act as pro-inflammatory cells under certain inflammatory conditions, such as autoimmune diseases. In this context, MDSCs could worsen the pro-inflammatory state in women, leading to miscarriage or implantation failure. Limitations, reasons for caution In order to validate these results, we should extend our cohort and control group. Moreover, we need to perform a functional evaluation of this subset so we could elucidate their role in these conditions. Wider implications of the findings MDSCs might be a good predictor for RM and RIF patients and with others (as expanded NK cells) may classify a subgroup of patients with a pro-inflammatory profile that can benefit from personalized therapies. Trial registration number Not aplicable

Lack of Association Between Sex Hormones, MDSCs, LDGs and pDCs in Males and Females With Systemic Lupus Erythematosus.

Plasmacytoid dendritic cells (pDCs) and low-density granulocytes (LDGs) are interferon-alpha producing cells that create a pro-inflammatory response in Systemic Lupus Erythematosus (SLE) leading to auto antibody production and organ damage. Both pDCs and LDGs have been shown to be dysfunctional in patients with active SLE. Myeloid-derived suppressor cells (MDSCs) have the capacity to control T and B cell activation and differentiation, and have recently been identified as cells of interest in SLE as well. While not fully understood, previous studies have suggested that pDCs are regulated in part by both X chromosome inactivation and estradiol. Whether sex chromosomes or sex hormones regulate MDSCs and LDGs remain to be determined. We aimed to explore the relative role of sex and sex hormones on pDC, MDSC and LDG frequency and function in SLE patients. We recruited patients with SLE as defined by ACR or SLICC classification criteria and healthy controls in conjunction with the Cleveland Clinic Lupus Cohort and Clinical Research Unit. We analyzed serum sex hormone levels by ELISA, and frequencies of pDCs, MDSCs, and LDGs among PBMCs and serum cytokine levels by flow cytometry. PBMCs were further analyzed for expression of genes involved in or induced by toll-like receptor (TLR)7 or TLR9 stimulation. In all SLE patients, the serum estradiol/testosterone ratio and levels of granulocytic MDSCs and LDGs were increased, while levels of pDCs were decreased. Furthermore, pDCs from active SLE patients expressed lower levels of TLR7 and TLR9 and showed diminished production of TLR9-induced IFNα and TNFα as compared to healthy controls. LDGs from healthy controls and SLE patients expressed very low levels of TLR7 and TLR9 and largely failed to respond to TLR9 stimulation. Thus, regardless of sex and sex-hormone levels, frequencies of pDCs, MDSCs and LDGs, TLR7 and TLR9 expression, and TLR9-driven cytokine production were similarly altered in male and female SLE patients.