Analysis of Treg Cell Population Alterations in the Peripheral Blood of Patients Treated Surgically for Ovarian Cancer - A Preliminary Report

Genetically evaluating the causal role of peripheral immune cells in colorectal cancer: a two-sample Mendelian randomization study

BACKGROUND

Investigating novel therapeutic strategies for colorectal cancer (CRC) is imperative. However, there is limited research on the use of drugs to target peripheral blood immune cells in this context. To address this gap, we performed a two-sample Mendelian randomization (MR) analysis to identify potential therapeutic targets for CRC.

METHODS

We applied two-sample MR to identify the causal relationship between peripheral blood immune cells and CRC. GWAS data were obtained from the IEU OPEN GWAS project. Based on the implications from the MR results, we conducted a comprehensive database search and genetic analysis to explore potential underlying mechanisms. We predicted miRNAs for each gene and employed extensive research for potential therapeutic applications.

RESULTS

We have identified causal associations between two peripheral immune cells and colorectal cancer. Activated & resting Treg %CD4 + cell was positively associated with the risks of CRC, while DN (CD4-CD8-) %leukocyte cell exhibited a protective role in tumor progression. NEK7 (NIMA related kinase 7) and LHX9 (LIM homeobox 9) expressed in Treg cells were positively associated with CRC risks and may play a vital role in carcinogenesis.

CONCLUSIONS

This study identified causal relationship between peripheral immune cell and CRC. Treg and DN T cells were implicated to own promoting and inhibiting effects on CRC progression respectively. NEK7 and LHX9 in Treg cells were identified as potential biotarget for antitumor therapies.

Potential tools for predicting response to chemotherapy in OC: Assessment of immune dysbiosis, participant's self-rated health and microbial dynamics

Epithelial ovarian cancer (OC) is the deadliest female reproductive cancer; an estimated 13,270 women will die from OC in 2023. Platinum-based chemotherapy resistance mechanisms contribute to poor OC 5-year survival rates. Peripheral inflammation is linked to various disease states and we previously identified unique peritoneal microbial features predictive of OC. We hypothesized that unique peripheral immune profiles and peritoneal microbial features may be predictive of disease-free interval (time to recurrence) and response to chemotherapy in participants with OC. We also investigated self-rated health (SRH) scores in the context of peripheral inflammation as a potential screening tool for OC. Blood and peritoneal fluid were collected from participants with OC or a benign adnexal mass (BPM). Lymphocyte populations were analyzed using Fluorescence Activated Cell Sorting, serum cytokine levels were analyzed using the Human Th17 Magnetic Bead Panel assay and peritoneal fluid microbial features were analyzed using Next Generation Sequencing (NGS). Participants completed a standardized questionnaire on self-rated physical and emotional health. Participants were classified into three chemotherapy response categories: platinum-refractory, platinum-resistant or platinum-sensitive. A significant positive correlation was found between elevated inflammatory status on the day of surgery and longer disease-free interval. SRH measures did not correlate with immune status in participants with OC or a BPM. We identified a correlation between peritoneal microbial features and chemotherapy response. We conclude that immune dysbiosis may be useful in predicting OC recurrence. The immune findings reported here set the framework for additional studies utilizing immune profiles to predict platinum-based chemotherapy responsiveness in OC.

NKG2D-mediated cytotoxicity improves after primary surgery for high-grade serous ovarian cancer

PROBLEM

Tumors compromise the patients' immune system to promote their own survival. We have previously reported that HGSC exosomes play a central role, downregulating NKG2D cytotoxicity. Primary surgery's effect on tumor exosomes and NKG2D cytotoxicity in HGSC patients has not been studied before. The overall objective of this study was to explore the effect of surgery on the exosome-induced impairment of NKG2D cytotoxicity in HGSC.

METHOD OF STUDY

Paired pre- and post-operative blood samples were subjected to cell and exosome analyses regarding the NKG2D receptor and ligands, and NKG2D-mediated cytotoxicity. Lymphocytes were phenotyped by immunoflow cytometry. Exosomes, isolated by ultracentrifugation, and characterized by nanoparticle tracking analysis, transmission and immune electron microscopy and western blot were used in functional cytotoxic experiments. HGSC explant culture-derived exosomes, previously studied by us, were used for comparison.

RESULTS

HGSC exosomes from patients' sera downregulated NKG2D-mediated cytotoxicity in NK cells of healthy donors. In a subgroup of subjects, NKG2D expression on CTLs and NK cells was upregulated after surgery, correlating to a decrease in the concentration of exosomes in postoperative sera. An overall significantly improved NKG2D-mediated cytotoxic response of the HGSC patients' own NK cells in postoperative compared to preoperative samples was noted.

CONCLUSIONS

Surgical removal of the primary tumor has a beneficial effect, relieving the exosome-mediated suppression of NKG2D cytotoxicity in HGSC patients, thus boostering their ability to combat cancer.

Peripheral lymphocyte populations in ovarian cancer patients and correlations with clinicopathological features

Background

To investigate the alterations of peripheral lymphocyte subpopulations in ovarian cancer patients compared to benign or borderline counterparts. The possible clinicopathological implications were also evaluated.

Methods

We enrolled 112 treatment-naive ovarian cancer patients, 14 borderline tumor patients and 44 benign tumor patients between 09/2016 and 01/2019. Flow cytometry was used to measure the peripheral lymphocyte subsets consisting of T cells (CD3⁺, CD3⁺CD4⁺, CD3⁺CD8⁺ and CD8⁺CD28⁺), regulatory T cells (Tregs, CD4⁺CD25⁺CD127⁻), natural killer cells (NK cells, CD3⁻CD56⁺) and B cells (CD19⁺).

Results

Most ovarian cancer patients were high-grade serous carcinoma (84.8%), followed by clear cell carcinoma (8.03%). Late-stage tumor (FIGO III + IV) accounted for 82.1%. The study showed that the proportions of peripheral lymphocyte subsets underwent apparent changes in ovarian cancer patients. We observed elevated levels of Treg cells in patients with both ovarian borderline and malignant tumor compared to those with benign tumors, which achieved statistic significance. In contrast, CD3⁺CD8⁺ T and CD8⁺CD28⁺ T cells were significantly lower in ovarian cancer patients. Interestingly, low level of B cells was correlated to clear cell carcinoma (P = 0.024), advanced tumor (P = 0.028) and platinum-resistant recurrence (P = 0.014). Regarding the changes of lymphocyte subsets after surgery, CD8⁺CD28⁺ T cells had a significant decreasing tendency (P = 0.007) while B cells were the opposite (P < 0.001).

Conclusions

Ovarian cancer patients have altered circulating lymphocyte profile (elevated Treg cell, depressed CD3⁺CD8⁺ T and CD8⁺CD28⁺ T cells). Low level of B cells might be related to disease aggressiveness, and it recovered after the removal of tumor, which merits further study.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-022-00977-3.

1 Ovarian cancer patients have altered circulating lymphocyte profile

2 Low level of B cells might be related to disease aggressiveness, and it recovered after the removal of tumor.

Changes in peripheral lymphocyte populations in patients with advanced/recurrent ovarian cancer undergoing splenectomy during cytoreductive surgery

BACKGROUND

To investigate changes in peripheral lymphocyte subsets after splenectomy during cytoreductive surgery for advanced or recurrent ovarian cancers.

METHODS

We enrolled 83 patients with advanced or recurrent ovarian cancer who underwent cytoreductive surgery. Twenty patients who also underwent splenectomy were assigned to the splenectomy cohort and the rest were assigned to the non-splenectomy cohort. Flow cytometry was used to measure peripheral lymphocyte subsets consisting of T cells, regulatory T cells, natural killer cells, B cells, and activation antigens before and after surgery.

RESULTS

There was no difference in the number and distribution of peripheral lymphocyte subsets between the two cohorts before surgery. After surgery, we observed elevated levels of T cells (CD3⁺, CD3⁺CD8⁺) in the splenectomy cohort compared to those in the non-splenectomy cohort, and the difference was statistically significant. CD8⁺CD28⁺ T cells had a significant decreasing tendency (P = 0.011) while CD3⁺/HLA-DR⁺ T cells showed the opposite trend (P = 0.001) in the splenectomy cohort. The proportion of Tregs (P = 0.005) and B cells (P < 0.001) including CD3^-/HLA-DR⁺ B cells (P = 0.007) increased after surgery, and the absolute number of T cells and NK cells decreased to different extents (P < 0.001) in the non-splenectomy cohort. The post-operative percentage of CD8⁺CD28⁺ T cells was less than the pre-operative percentage (P = 0.022), which was similar to the splenectomy cohort. There was no significant difference in progression-free survival or overall survival between the groups after a median follow-up time of 41 months.

CONCLUSIONS

The changes in peripheral lymphocyte populations were different between patients with and those without splenectomy during cytoreductive surgery for ovarian cancers. T cells were increased and activated in the splenectomy cohort, whereas, B cells were increased and activated in the non-splenectomy cohort.

The analysis of Treg lymphocyte blood percentage changes in patients with head and neck cancer during combined oncological treatment: a preliminary report

Introduction

In patients with cancer, Treg lymphocytes seem to play an important role in promoting tumour growth. The number of circulating Treg cells has been associated with poor survival among patients suffering from various types of cancers. The aim of the present study was to evaluate the changes in the percentage levels of Treg lymphocytes in the blood samples of patients with head and neck cancer during combined treatment with respect to the stage of the disease and the intensity of the radiation reaction as monitored using the Dische scale.

Material and methods

Peripheral blood samples were collected from 20 head and neck cancer patients prior to the combined oncological treatment, during, and then one week after the completion of the therapy.

Results

A statistically significantly higher percentage of CD3⁺/CD4⁺/CD25⁺/FoxP3⁺/CD127(^–/low) T cells within the CD3⁺/CD4⁺ T cell population was detected in patients during radiotherapy (RTH), chemotherapy (CTH), and chemoradiotherapy (CRT) than before the treatment began (p < 0.0001). A statistically significantly higher percentage of CD3⁺/CD4⁺/CD25⁺/FoxP3⁺/CD127(^–/low) T cells within the CD3⁺/CD4⁺ T cell population was detected after RTH/CRT than before treatment, with respect to the radiation reaction as evaluated using the Dische scale (p = 0.0150).

Conclusions

The increase in the percentage of Treg cells correlated with an increase in the intensity of the radiation reaction measured using the Dische scale which indicates the advance of the oral mucositis reaction to RTH. In conclusion, because the role of Treg lymphocytes in cancer patients is complex, it is necessary to monitor the percentages of these cells in patients during combined oncological therapies.

FOXP3 expression in FOXP3+ tumor cells promotes hepatocellular cells metastasis

BACKGROUND

Forkhead transcription factor 3 (FOXP3) is a key molecule for the development of regulatory T cell. Recent studies showed that FOXP3 was also expressed in tumor cells. This study is designed to identify the expression of FOXP3 and its pathogenesis in hepatocellular carcinoma (HCC).

METHODS

Through immunohistochemistry, RNA extraction and Real-Time Quantitative PCR, western blot analysis, transwell cell migration assay and invasion assays, and in vivo experiment, we detected FOXP3 expression in HCC and analyzed the expression of tumor metastasis-related genes in HCC cells using female BALB/c-Nude mice.

RESULTS

The results showed that FOXP3 was expressed in partial HCC tissues samples and cell lines. The distant metastasis rate was remarkably higher in the FOXP3 positive HCCs than that in the negative group. The positive rate of FOXP3 expression in the metastatic HCC was higher than that in primary HCC, and the expression level of FOXP3 was found to increase as the enhancement in the metastatic potential of the cell lines. Furthermore, in HCC cell lines, FOXP3 overexpression can promote the cell metastasis and invasion by regulating MMP-1. The in vivo experiment showed that the proliferation ability of HepG2 cells in nude mice increased significantly after FOXP3 was overexpressed, and the incidence rate of lung metastasis in MHCC97L cells was significantly deceased after knocking down the FOXP3 expression.

CONCLUSIONS

Our findings support that partial HCC tissues and cell lines expressing FOXP3 can promote the metastasis by regulating MMP-1.

Changes in regulatory T cells in patients with ovarian cancer undergoing surgery: Preliminary results

Regulatory T cells (Treg) suppress immune responses in patients with cancer. Surgery is the most effective therapeutic strategy for ovarian cancer (OC). However, the interplay between the Treg population and surgical resection remains unclear. 61 patients with OC who received no prior treatment were enrolled in the study. Treg percentages were characterized from peripheral blood mononuclear cells. We investigated CD4⁺CD25⁺, CD4⁺CD25⁺Foxp3⁺, CD8⁺CD28^-, and CD8⁺Foxp3⁺ Tregs in OC patients and their postoperative changes using flow cytometry. Treg percentages were significantly higher in OC patients than those in benign ovarian tumors (BOT) and healthy controls. Higher percentages of Tregs were found in patients with stage III/IV than stage I/II OC. Treg percentages were significantly decreased postoperatively. The postoperative Treg percentages in patients with stage I/II OC were similar to those in BOT patients, while postoperative Treg percentages in patients with stage III/IV OC remained higher. Tregs were markedly lower on postoperative day (POD) 3 than preoperatively. They increased slightly after 7days, but remained lower than preoperative levels. These data suggested that Tregs continued to decline from POD 7 to POD 30. Treg percentages are correlated with the tumor burden and could be a key factor in monitoring the immunological status of patients with OC.

Ontogeny of Tumor-associated CD4+CD25+Foxp3+ T-regulatory Cells

The critical contribution of CD4+CD25+Foxp3+ T-regulatory cells (Treg) to immune suppression in the tumor microenvironment is well-established. Whereas the mechanisms that drive the generation and accumulation of Treg in tumors have been an active area of study, the information on their origin and population dynamics remains limited. In this review, we discuss the ontogeny of tumor-associated Treg in light of the recently identified lineage markers.

[Immunological aspects of ovarian cancer: Therapeutic perspectives]

Ovarian cancer is recognized by the immunological system of its host. Initially, it is effective to destroy and eliminate the cancer. But gradually, resistant tumor cells more aggressive and those able to protect themselves by inducing immune tolerance will be selected. Immunotherapy to be effective should consider both components of immune response with an action on cytotoxic immune effectors and action on tolerance mechanisms. The manipulations of the immune system should be cautious, because the immune effects are not isolated. A theoretically efficient handling may simultaneously cause an adverse effect which was not envisaged and could neutralize the benefits of treatment. Knowledge of tolerance mechanisms set up by the tumor is for the clinician a prerequisite before they prescribe these treatments. For each cancer, the knowledge of its immunological status is a prerequisite to propose adapted immunological therapies.

Frequency of CD4+CD25+Foxp3+ cells in peripheral blood in relation to urinary bladder cancer malignancy indicators before and after surgical removal

Tumor cells communicate with stromal cells, including cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs), to form microenvironment inhibiting immune responses. Regulatory T cells (Tregs, CD4+CD25+FoxP3+) stimulate immune tolerance and facilitate tumor progression. We analyzed the changes in Treg frequencies assessed using flow cytometry in the peripheral blood of patients with urothelial bladder cancer before and after tumor-removal. Changes in Treg frequency were investigated in relation to clinicopathomorphological indicators of tumor malignancy and expression of RCAS1 on CAFs and TAMs. Higher Treg frequencies were observed in early phase of tumor growth (pTa-pT2), in larger tumors, with more aggressive type of invasion, and with expression of RCAS1. The later phase of tumor development, accompanied by a nonclassic differentiations and pT3-pT4 advancement, had lower number of tumor infiltrating lymphocytes (TILs) and lower Treg frequency. Furthermore, in pT2-pT4 tumors, a decreased post-surgery Treg frequency was associated with poorer prognosis: patients with the lowest frequency of Tregs died first. These findings strongly suggest that the Treg frequencies at later phase of tumor growth, associated with a low anti-tumor response, represent a new and important prognostic indicator in urinary bladder cancer.

Changes in Immunogenicity during the Development of Urinary Bladder Cancer: A Preliminary Study

In the present study, we evaluated tumor-infiltrating lymphocytes (TILs) and blood regulatory T lymphocyte (Tregs, CD4+/CD25+/FoxP3+) expression in bladder cancer patients. The number of CD4+, CD8+, CD25+, FoxP3+ and CD20+ TILs was analyzed in association with clinico-pathomorphological features. In more advanced metastasizing tumors, showing non-classic differentiation (ND) and a more aggressive tissue invasion type (TIT), the number of TILs decreased. A low number of CD4+ TILs was associated with poor prognosis. Similarly, Treg frequency before surgery and after surgical treatment was significantly lower in more advanced tumors. The changes in TILs, as well as of local and systemic Tregs, were accompanied by changes in the histological phenotype of urothelial carcinoma regarding pT stage, NDs, TIT, and clinical outcomes. The number of TILs and the frequency of blood Tregs (indicators of antitumor response) may be essential for choosing an immunotherapy that is adjusted to the immune status according to the phase of tumor growth. Moreover, a significant reduction in the number of CD4+ and CD8+ TILs with the development of NDs in more advanced tumors may be associated with lower tumor immunogenicity, resulting in immune tolerance towards tumor tissue. These observations and the tendency of urothelial bladder carcinoma to undergo NDs in a heterogeneous manner during tumor progression suggest complex interactions between bladder cancer immunogenicity and stages of tumor progression.

FOXP3+ Tregs: heterogeneous phenotypes and conflicting impacts on survival outcomes in patients with colorectal cancer

The tumor microenvironment composites a mixture of immune lymphoid cells, myeloid cells, stromal cells with complex cytokines, as well as numerous lymphovascular vessels. Colorectal cancer (CRC) is a common malignancy and one of the leading causes of tumor-related death in the United States and worldwide. The immune status in the tumor microenvironment contributes to the survival of a patient with CRC. Regulatory T cells (Tregs) are considered a key factor in immune escape and immunotherapy failure among cancer patients. The transcription factor forkhead box P3 (FOXP3) is a crucial intracellular marker and also a key developmental and functional factor for CD4+CD25+ Tregs. Tregs are correlated with survival in various human neoplasms, and elevated proportions of Tregs are usually associated with unfavorable clinical outcomes. However, the role of Tregs in CRC remains controversial. High densities of tumor-infiltrating Tregs in CRC patients are reported to be correlated with worse or better outcomes. And Tregs may not be predictive of prognosis after resection of the primary tumor. The exact explanations for these discordant results remain unclear. The heterogeneous instincts of cell phenotype, gene expression, and functional activities of Tregs may partly contribute this contrasting result. Furthermore, the lack of a robust marker for identifying Tregs or due to the different techniques applied is also account. The Treg-specific demethylated region (TSDR) was recently reported to be a specific epigenetic marker for natural Tregs (nTregs), which can stably express FOXP3. The FOXP3-TSDR demethylation assay may be an promising technique for CRC-related nTregs studies.

Effects of gastric cancer cells on the differentiation of Treg cells

The aim of this study was evaluated the prevalence of Treg cells in peripheral blood in patients with gastric cancer, and investigate the effect of gastric cancer cells on their differentiation. ELISA was employed to assess the concentrations of TGF-β and IL-10 in gastric cancer patients' serum. Then, mouse gastric cancer cells were co-cultured with T lymphocytes or T lymphocytes + anti-TGF-β. Flow cytometric analysis and RT-PCR were then performed to detect Treg cells and TGF-β and IL-10 expression in gastric cancer cells. Our data showed that the expression of TGF-β and IL-10 in the patients with gastric cancer was increased compared to the case with healthy donors. The population of Treg cells and the expression levels of TGF-β and IL-10 in the co-culture group were much higher than in the control group (18.6% vs 9.5%) (P<0.05). Moreover, the population of Treg cells and the expression levels of TGF-β and IL-10 in the co-culture systerm were clearly decreased after addition of anti-TGF-β (7.7% vs 19.6%) (P<0.01). In conclusion, gastric cancer cells may induce Treg cell differentiation through TGF-β, and further promote immunosuppression.

Molecular mimics of the tumour antigen MUC1

A key requirement for the development of cancer immunotherapy is the identification of tumour-associated antigens that are differentially or exclusively expressed on the tumour and recognized by the host immune system. However, immune responses to such antigens are often muted or lacking due to the antigens being recognized as "self", and further complicated by the tumour environment and regulation of immune cells within. In an effort to circumvent the lack of immune responses to tumour antigens, we have devised a strategy to develop potential synthetic immunogens. The strategy, termed mirror image phage display, is based on the concept of molecular mimicry as demonstrated by the idiotype/anti-idiotype paradigm in the immune system. Here as 'proof of principle' we have selected molecular mimics of the well-characterised tumour associated antigen, the human mucin1 protein (MUC1) from two different peptide phage display libraries. The putative mimics were compared in structure and function to that of the native antigen. Our results demonstrate that several of the mimic peptides display T-cell stimulation activity in vitro when presented by matured dendritic cells. The mimic peptides and the native MUC1 antigenic epitopes can cross-stimulate T-cells. The data also indicate that sequence homology and/or chemical properties to the original epitope are not the sole determining factors for the observed immunostimulatory activity of the mimic peptides.

Role of myeloid-derived suppressor cells in tumor immunotherapy

Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells that infiltrate human and experimental tumors and strongly inhibit anticancer immune response directly or by inducing regulatory T-lymphocyte activity. Consequently, MDSCs are important actors of cancer-induced immune tolerance and a major obstacle to efficiency of cancer immunotherapy. Several means of preventing MDSCs accumulation or inhibiting their immunosuppressive effect were recently discovered in cancer-bearing hosts, contributing to restoring antitumor immunity and consequently to control of tumor growth. In experimental tumor models, targeting MDSCs can enhance the effects of active or passive immunotherapy. While similar effects have not yet been noted in cancer-bearing patients, recent preclinical findings demonstrating that the selective toxicity of conventional chemotherapies such as gemcitabine and 5-fluorouracil on MDSCs might contribute to their anticancer effect provide impetus to pursue investigations to unravel novel therapeutics that target MDSCs in humans.