Elevated Circulating CD4+CD25-Foxp3+ Regulatory T Cells in Patients with Nonsmall Cell Lung Cancer

Downregulation of lncRNA MIR17HG reduced tumorigenicity and Treg-mediated immune escape of non-small-cell lung cancer cells through targeting the miR-17-5p/RUNX3 axis

Long noncoding RNA MIR17HG was involved with the progression of non-small-cell lung cancer (NSCLC), but specific mechanisms of MIR17HG-mediated immune escape of NSCLC cells were still unknown. The present study investigated the function of MIR17HG on regulatory T cell (Treg)-mediated immune escape and the underlying mechanisms in NSCLC. Expression of MIR17HG and miR-17-5p in NSCLC tissue samples were detected using quantitative real-time PCR (qRT-PCR). A549 and H1299 cells were transfected with sh-MIR17HG, miR-17-5p inhibitor, or sh-MIR17HG + miR-17-5p inhibitor, followed by cocultured with Tregs. Cell proliferation was measured using 5-ethynyl-20-deoxyuridine (Edu) staining assay and cell counting kit-8 (CCK-8) assay. Flow cytometry was used for determining positive numbers of FOXP3+CD4+/CD25+/CD8+ Tregs. Through subcutaneous injection with transfected A549 cells, a xenograft nude mouse model was established. Weights and volumes of xenograft tumors were evaluated. Additionally, the expressions of immune-related factors including transforming growth factor beta (TGF-β), vascular endothelial growth factor A (VEGF-A), interleukin-10 (IL-10), IL-4, and interferon-gamma (IFN-γ) in cultured cells, were evaluated by enzyme-linked immunosorbent assay and western blot analysis. Then, miR-17-5p was decreased and MIR17HG was enhanced in both NSCLC tissues and cell lines. MIR17HG knockdown significantly suppressed cell proliferation, tumorigenicity, and immune capacity of Tregs in A549 and H1299 cells, whereas sh-MIR17HG significantly reduced expression levels of VEGF-A, TGF-β, IL-4, and IL-10 but promoted the IFN-γ level in vitro and in vivo. Moreover, downregulation of miR-17-5p significantly reversed the effects of sh-MIR17HG. Additionally, we identified that runt- related transcription factor 3 (RUNX3) was a target of miR-17-5p, and sh-MIR17HG and miR-17-5p mimics downregulated RUNX3 expression. In conclusion, downregulation of MIR17HG suppresses tumorigenicity and Treg-mediated immune escape in NSCLC through downregulating the miR-17-5p/RUNX3 axis, indicating that this axis contains potential biomarkers for NSCLC.

Qingfei mixture modulates the immune responses in lung cancer through modulating mTOR signaling and gut microbiota-derived short-chain fatty acids

Lung cancer ranks among the primary contributors to cancer-related fatalities on a global scale. Multiple research investigations have demonstrated that there exists a dysbiosis within the intestinal bacteria and short-chain fatty acids (SCFAs) is linked with immune responses in lung cancer. Qingfei mixture (QFM) has been widely used in treating lung cancer, yet the active ingredients and roles of the QFM on immune responses by targeting gut microbiota remain to be elucidated. The chemical constituents of QFM were qualitatively examined by UPLC/Q-TOF-MS. Additionally, we evaluated the therapeutic impact of the organic substance QFM on lung cancer, aiming to elucidate its mechanisms for improving the tumor-immune microenvironment. Herein, we constructed a Lewis lung carcinoma (LLC)-bearing mice model with QFM treatment to observe tumor growth and immune cell changes. Then, the feces were collected and a combinatory study using metagenomes, non-targeted metabonomics, and targeted metabonomics of SCFAs was performed. In vitro experiments have been conducted to estimate the roles of acetate and sodium propionate in CD8+ T cells. Furthermore, we treated tumor-bearing mice with QFM, QFM + MHY1485 (an mTOR activator), and QFM + an antibiotic mixture (ABX) to explore the potential therapeutic benefit of regulation of the tumor microenvironment. A total of 96 compounds were obtained from QFM by UPLC/Q-TOF-MS. Besides, the findings demonstrated that QFM exhibited significant efficacy against lung cancer, manifesting in reduced tumor growth and improved immune responses. In investigating its mechanisms, we integrated gut microbiota sequencing and fecal metabolomics, revealing that QFM effectively restored disruptions in gut microbiota and SCFAs in mice with lung cancer. QFM, acetate, or sodium propionate contributed to the up-regulation of IFN-γ, Gzms-B, perforin, IL-17, IL-6, IL-12, TNF-α expressions and decreased HDAC and IL-10 levels in vitro and in vivo. Moreover, MHY1485 and ABX weakened the effects of QFM on immunomodulation. Collectively, these results suggest that QFM may facilitate immune responses in the LLC-bearing mice via regulating the gut microbiota-derived SCFAs at least partially through targeting the mTOR signaling pathway.

Targeting T regulatory (Treg) cells in immunotherapy-resistant cancers

Primary or secondary (i.e., acquired) resistance is a common occurrence in cancer patients and is often associated with high numbers of T regulatory (Treg) cells (CD4+CD25+FOXP3+). The approval of ipilimumab and the development of similar pharmacological agents targeting cell surface proteins on Treg cells demonstrates that such intervention may overcome resistance in cancer patients. Hence, the clinical development and subsequent approval of Cytotoxic T Lymphocyte Antigen-4 (CTLA-4) targeting agents can serve as a prototype for similar agents. Such new agents aspire to be highly specific and have a reduced toxicity profile while increasing effector T cell function or effector T/T regulatory (Teff/Treg) ratio. While clinical development with large molecules has shown the greatest advancement, small molecule inhibitors that target immunomodulation are increasingly entering early clinical investigation. These new small molecule inhibitors often target specific intracellular signaling pathways [e.g., phosphoinositide-3-kinase delta (PI3K-δ)] that play an important role in regulating the function of Treg cells. This review will summarize the lessons currently applied to develop novel clinical agents that target Treg cells.

Tumor-infiltrating lymphocytes predict efficacy of immunotherapy in advanced non-small cell lung cancer: a single-center retrospective cohort study

BACKGROUND/PURPOSE

The current study aimed to investigate the correlation between tumor-infiltrating lymphocytes (TILs) and immunotherapy efficacy in patients with advanced non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

Eighty-nine patients with advanced NSCLC who received immune checkpoint inhibitors (ICIs) monotherapy were retrospectively enrolled in this study. The density of TILs in paraffin-embedded pathological tissues taken before receiving ICIs was quantitatively analyzed by immunohistochemical staining. The density of TILs was treated as a dichotomous variable using the median as the cutoff value. The Kaplan-Meier analysis was used to assess survival differences between groups. Univariate and multivariate Cox analyses were applied to screen out independent prognostic factors and further construct a nomogram prediction model to predict survival.

RESULTS

Survival analysis showed that CD8+ TILs, CD4+ TILs, and IFN-γ+ Th1 were significant positive indicators for predicting progression-free survival (PFS) and overall survival (OS) (p < 0.05), whereas Foxp3+ Treg were a significant negative predictor (p < 0.05). The predictive role of IL-4+ Th2 was not apparent in this study and requires further investigation and exploration (p > 0.05). The nomogram prediction model exhibited good discriminative ability, with C-index values of 0.723 (95% CI 0.682-0.764) and 0.793 (95% CI, 0.738-0.848) in the training cohort and validation cohort, respectively. The AUC values indicated that the nomogram prediction model had high predictive value and the calibration curve presented good prediction accuracy.

CONCLUSIONS

TILs could predict the efficacy of immunotherapy and may become a promising predictor.

Circulating T regulatory cell subsets in patients with untreated lung cancer

INTRODUCTION

Regulatory T Cells (Tregs) play an important role in carcinogenesis and tumor immunoediting by preventing the development of effective antitumor immunity. Several reports showed that circulating Tregs are increased in patients with solid tumors, including lung cancer. Treg population could be categorized into "naive," "effector," and "memory" subtypes, bearing potential unique functions. However, the data regarding the prognostic impact of these Tregs subtypes is limited in lung cancer. The aim of this study was to investigate the frequency of different circulating Tregs subtypes in lung cancer and their correlation with clinical outcomes.

METHODS

We analyzed the frequency of circulating CD4, CD8 and, Tregs lymphocytes in 66 patients with lung cancer and 32 healthy controls using flow cytometry. Circulating Tregs subtypes: naïve (CD3+ , CD4+ , CCR4+ , CD25+ and CD127low, CD45RO-), memory (CD3+ , CD4+ , CCR4+ , CD25+ and CD127low, CD45RO+) and the expression of the activation marker HLA-DR were correlated with overall survival.

RESULTS

The percentage and the absolute number of total, memory and activated Tregs was significantly higher in lung cancer patients than healthy controls. Patients with a Tregs percentage higher than 5.4% and higher than 20% of HLA-DR + Tregs had worse overall survival than those with lower levels.

CONCLUSIONS

Circulating Tregs and activated Tregs are a potential prognostic factor in patients with lung cancer treated with conventional therapy and could be considered a predictive biomarker in patients not eligible for immune blockade treatments. Additionally, it will be interesting to study these Tregs subsets for immune treatments in future clinical trials.

Benzo[a]pyrene immunogenetics and immune archetype reprogramming of lung

Overexposure to carcinogenic precursor, benzo[a]pyrene [BaP], modulates the lung immune microenvironment. The present review seeks to elucidate novel pathways behind the tumor effect of BaP in the lungs, emphasizing immunomodulatory mediators and immune cells. In this review, BaP reprograms lung immune microenvironment through modulating transforming growth factor-beta (TGF-β), programmed cell death 1 (PD-1), cytotoxic T lymphocyte antigen-4 (CTLA-4), Interleukin 12 (IL-12), indoleamine 2,3 dioxygenase (IDO), forkhead box protein P3 (FOXP3) and interferon-gamma (IFN-γ) levels. Moreover, BaP modulated lung immune cellular architecture such as dendritic cells, T cells, Tregs, macrophages, neutrophils, and myeloid-derived suppressor cells (MDSCs). All mentioned changes in immune architecture and mediators lead to the induction of lung cancer.

Randomized phase II trial of a first-in-human cancer cell lysate vaccine in patients with thoracic malignancies

BACKGROUND

Although most malignancies express cancer-testis antigens (CTA), immune responses to these proteins are limited in thoracic oncology patients. This trial was undertaken to examine if a cancer cell lysate vaccine could induce immunity to CTA, and to ascertain if metronomic cyclophosphamide and celecoxib enhances vaccine-induced immune responses.

METHODS

Eleven patients with primary thoracic malignancies and 10 patients with extrathoracic neoplasms metastatic to the chest rendered NED by conventional therapies were randomized to receive H1299 lung cancer cell lysates (10 mg protein/vaccine) with Iscomatrix™ adjuvant via deep intradermal injection q 4 weeks ×6 with or without daily oral metronomic cyclophosphamide/celecoxib. The primary endpoint was serologic response to purified CTA assessed 1 month after the 6th vaccination. Secondary endpoints included assessment of the effects of cyclophosphamide and celecoxib on frequency and magnitude of vaccine-induced immune responses to CTA. Exploratory endpoints included evaluation of the effects of the vaccine regimens on peripheral immune subsets. Standard of care imaging studies were obtained at baseline and 1 month after the 3rd and 6th vaccinations.

RESULTS

All patients exhibited local and systemic inflammatory responses lasting 72-96 hours following vaccinations. There were no dose limiting treatment related toxicities. Fourteen patients (67%) completed all six vaccinations. Eight of 14 patients (57%) exhibited serologic responses to NY-ESO-1. One patient developed antibodies to GAGE7; several patients exhibited reactivity to XAGE and MAGE-C2. Vaccine therapy decreased the percent of Tregs (P=0.0068), PD-1 expression on Tregs (P=0.0027), PD-L1 expression on CD14+ monocytes (P=0.0089), PD-L1 expression on classical monocytes (P=0.016), and PD-L1 expression on intermediate monocytes (P=0.0031). Cyclophosphamide/celecoxib did not appear to increase immune responses or enhance vaccine-induced alterations in peripheral immune subsets.

CONCLUSIONS

H1299 lysate vaccines with Iscomatrix™ induce immune responses to CTA and modulate peripheral immune subsets in a manner that may enhance antitumor immunity in patients with thoracic malignancies.

Blood biomarkers associated to complete pathological response on NSCLC patients treated with neoadjuvant chemoimmunotherapy included in NADIM clinical trial

BACKGROUND

Immunotherapy is being tested in early-stage non-small cell lung cancer (NSCLC), and achieving higher rates of complete pathological responses (CPR) as compared to standard of care. Early identification of CPR patients has vital clinical implications. In this study, we focused on basal peripheral immune cells and their treatment-related changes to find biomarkers associated to CPR.

METHODS

Blood from 29 stage IIIA NSCLC patients participating in the NADIM trial (NCT03081689) was collected at diagnosis and post neoadjuvant treatment. More than 400 parameters of peripheral blood mononuclear cells (PBMCs) phenotype and plasma soluble factors were analyzed.

RESULTS

Neoadjuvant chemoimmunotherapy altered more than 150 immune parameters. At diagnosis, 11 biomarkers associated to CPR were described, with an area under the ROC curve >0.70 and p-value <.05. CPR patients had significantly higher levels of CD4+ PD-1+ cells, NKG2D, and CD56 expression on T CD56 cells, intensity of CD25 expression on CD4+ CD25hi+ cells and CD69 expression on intermediate monocytes; but lower levels of CD3+ CD56- CTLA-4+ cells, CD14++ CD16+ CTLA-4+ cells, CTLA-4 expression on T CD56 cells and lower levels of b-NGF, NT-3, and VEGF-D in plasma compared to non-CPR. Post treatment, CPR patients had significantly higher levels of CD19 expression on B cells, BCMA, 4-1BB, MCSF, and PARC and lower levels of MPIF-1 and Flt-3L in plasma compared to non-CPR.

CONCLUSIONS

Patients achieving CPR seem to have a distinctive peripheral blood immune status at diagnosis, even showing different immune response to treatment. These results reinforce the different biology behind CPR and non-CPR responses.

Regulatory T-Cells as an Emerging Barrier to Immune Checkpoint Inhibition in Lung Cancer

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment paradigm for lung cancer in recent years. These strategies consist of neutralizing antibodies against negative regulators of immune function, most notably cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), and PD-1 ligand 1 (PD-L1), thereby impeding the ability of tumor cells to escape immune surveillance. Though ICIs have proven a significant advance in lung cancer therapy, overall survival rates remain low, and lung cancer continues to be the leading cause of cancer-related death in the United States. It is therefore imperative to better understand the barriers to the efficacy of ICIs, particularly additional mechanisms of immunosuppression within the lung cancer microenvironment. Recent evidence suggests that regulatory T-lymphocytes (Tregs) serve as a central mediator of immune function in lung cancer, suppressing sterilizing immunity and contributing to the clinical failure of ICIs. Here, we provide a comprehensive summary of the roles of Tregs in lung cancer pathobiology and therapy, as well as the potential means through which these immunosuppressive mechanisms can be overcome.

Identification of Biomarkers Related to CD8+ T Cell Infiltration With Gene Co-expression Network in Lung Squamous Cell Carcinoma

Lung squamous cell carcinoma (LSCC) is one of the most common types of lung cancer in adults worldwide. With the development of modern medicine, cancer treatment that harnesses the power of the immune system might be particularly effective for treating LSCC. In this research, LSCC expression data, which quantify the cellular composition of immune cells, were analyzed by weighted gene coexpression network analysis (WGCNA) and a deconvolution algorithm based on the Gene Expression Omnibus (GEO) database, and the results indicated a close relationship between LSCC and CD8+ T cells. Six hub genes (SYT3, METTL8, HSPB3, GFM1, ERLIN2, and CLCN2) were verified by gene-gene network and protein-protein interaction (PPI) network analyses. We found that the six hub genes were increased in cancer tissues and were closely correlated with cancer development and progression. After immune correlation analysis, METTL8 was selected as a prognostic biomarker. Finally, we found that the METTL8 levels were increased in multiple lung cancer cell lines and LSCC tissues. METTL8 inhibition could clearly induce G1 cell cycle arrest and suppress proliferation. Therefore, METTL8, which is related to CD8+ T cell infiltration, might be identified as a potential biomarker and gene therapy target in LSCC.

The therapeutic potential of attenuated diphtheria toxin delivered by an adenovirus vector with survivin promoter on human lung cancer cells

Adenoviral vectors are superior to plasmid vectors in their gene transport efficiency. The A subunit of the diphtheria toxin (DTA) gene is a popular suicide gene in cancer gene therapy. However, DTA is seldom used in adenoviral therapy due to its great toxicity. The toxicity of DTA is so great that even a single molecule of DTA is enough to kill one cell. To avoid this highly toxic effect on normal cells, DTA should be controlled by tumor-specific promoters. The survivin promoter is a widely used tumor-specific promoter. But genes driven by the survivin promoter show a low level of basal gene expression in non-cancer cells. DTA driven by the survivin promoter in adenoviral vectors may be highly toxic not only to cancer cells but also to normal cells. Therefore, DTA should be attenuated when it is used in adenoviral vectors driven by the survivin promoter. In this study, we compared the three kinds of recombinant adenoviruses that carry DTA or its attenuated forms (DTA176 and DTA197) in the treatment of human lung cancer. The results showed that in comparison with both DTA and DTA176, DTA197 is more suitable for adenoviral cancer therapy controlled by the survivin promoter. In addition, Adsur-DTA197 (DTA197 delivered by an adenoviral vector with the survivin promoter) sensitized human lung cancer cells to cisplatin both in vitro and in vivo. These results indicated that Adsur-DTA197 may be a potential chemosensitizer in cancer therapy.

CD4+CD25-FoxP3+ T cells: a distinct subset or a heterogeneous population?

In addition to generating effective immunity against infectious agents, the immune system helps to fight against different noninfectious human diseases while maintaining the balance between self and non-self discrimination. The breakdown of tolerance in autoimmune diseases or sustainable tolerance in an abnormal microenvironment such as chronic inflammation may initiate the process of malignancy. Immune system regulation is controlled by a complex, dynamic network of cells and mediators. Understanding the cellular and molecular basis of immune regulation provides better insight into the mechanisms governing the immune pathology of diseases. Among several cellular subsets and mediators with regulatory roles, a subpopulation of CD4⁺ T cells was recently reported to be positive for FoxP3 and negative for CD25, with a suggested range of functional activities in both cancer and autoimmune diseases. This CD4 subset was first reported in 2006 and thought to have a role in the pathogenesis of cancer. However, the spectrum of roles played by this T cell subset is broad, and no consensus has been reached regarding its immunological functions. In this review, we focused on the possible origin of CD4⁺CD25^‒FoxP3⁺ T cells and their function in cancer and autoimmune diseases.

Baicalin suppresses Th1 and Th17 responses and promotes Treg response to ameliorate sepsis-associated pancreatic injury via the RhoA-ROCK pathway

Recent studies have reported that the imbalance of T helper 1 cell (Th1), Th17 and regulatory T cell (Treg) have been confirmed to play a vital role in the development of sepsis and other inflammatory diseases. Baicalin (BA) has anti-inflammatory properties and improves survival in sepsis. We investigated whether baicalin could regulate Th1, Th17 and Treg responses to ameliorate sepsis-associated pancreatic injury through the ras homolog family member A (RhoA)-Rho kinase (ROCK) pathway. The sepsis model was established by using the cecal ligation and puncture (CLP) method. Fifty mice were randomly divided into five groups (n = 10): sham group, model group, low-dose group (BA-L, 100 mg/kg of baicalin), medium-dose group (BA-M, 200 mg/kg of baicalin) and highdose group (BA-H, 300 mg/kg of baicalin). The effects of baicalin on the pancreatic injury, on changes of Th1, Th17 and Treg cells in vivo and in vitro, on RhoA, ROCK1 and signal transducer and activator of transcription (STAT) signaling pathways, and on levels of interferon-γ (IFN-γ), interleukin-17 (IL-17) and IL-10 were examined. Treatment of the CLP mice with baicalin significantly reduced the extent, scope and severity of the pathological changes of sepsis-associated pancreatic injury. Baicalin evidently reduced Th1 and Th17 cells and increased Treg cells in peripheral blood, spleen, pancreatic tissue and significantly inhibited T-box protein expressed in T cells (T-bet), retinoic acid receptor-related orphan receptor γt (RORγt) and increased forkhead/winged helix transcription factor (Foxp3) expressions in the pancreatic tissue. Baicalin reduced the expressions of RhoA, ROCK1, phosphorylated STAT4 (p-STAT4), p-STAT3 and increased the expression of p-STAT5 in peripheral blood, spleen and pancreatic tissue. Baicalin reduced the expressions of IFN-γ and IL-17 and increased the IL-10 in serum and pancreatic tissue. Baicalin is capable of ameliorating sepsis-associated pancreatic injury and regulating Th1, Th17 and Treg responses in sepsis. The present study provided a potential adjunctive therapy for treating pancreatic injury in sepsis, and further study is needed to reveal its deeper mechanisms.

Tumor microenvironment characterization identifies two lung adenocarcinoma subtypes with specific immune and metabolic state

The tumor microenvironment (TME) is a vital component of tumor tissue. Increasing evidence suggests their significance in predicting outcomes and guiding therapies. However, no studies have reported a systematic analysis of the clinicopathologic significance of TME in lung adenocarcinoma (LUAD). Here, we inferred tumor stromal cells in 1184 LUAD patients using computational algorithms based on bulk tumor expression data, and evaluated the clinicopathologic significance of stromal cells. We found LUAD patients showed heterogeneous abundance in stromal cells. Infiltration of stromal cells was influenced by clinicopathologic features, such as age, gender, smoking, and TNM stage. By clustering stromal cells, we identified 2 clinically and molecularly distinct LUAD subtypes with immune active and immune repressed features. The immune active subtype is characterized by repressed metabolism and repressed proliferation of tumor cells, while the immune repressed subtype is characterized by active metabolism and active proliferation of tumor cells. Differentially expressed gene analysis of the two LUAD subtypes identified an immune activation signature. To diagnose TME subtypes practically, we constructed a TME score using principal component analysis based on the immune activation signature. The TME score predicted TME subtypes effectively in 3 independent datasets with areas under the receiver operating characteristic curves of 0.960, 0.812, and 0.819, respectively. In conclusion, we proposed 2 clinically and molecularly distinct LUAD subtypes based on tumor microenvironment that could be valuable in predicting clinical outcome and guiding immunotherapy.

The prognostic role of circulating CD8+ T cell proliferation in patients with untreated extensive stage small cell lung cancer

BACKGROUND

Immunosuppression caused by tumorigenesis may promote tumor progress and invasion. Here, we investigated whether the characteristics of circulating T lymphocyte subtypes in patients with extensive small cell lung cancer (ED-SCLC) can be used as an alternative marker of tumor progression.

METHODS

This study included 36 newly diagnosed ED-SCLC patients before treatment and the patients were followed up. 22 age and sex-matched healthy volunteers were selected as control. The percentages and proliferation potential of T lymphocyte subpopulations from peripheral blood were measured.

RESULTS

CD4⁺ CD25⁺ Foxp3⁺ regulatory T cells (Tregs) were elevated in ED-SCLC patients compared with healthy controls (p = 0.0083). In contrast, the percentages of CD3⁺ and CD3⁺CD4⁺ T cells were significantly lower in SCLC patients (p < 0.001; p = 0.0014). The proliferation (%divided) of CD8⁺ T cells of SCLC patients was suppressed compared with healthy controls (p = 0.0058), but not of CD4⁺ T cells (p = 0.1611). Multivariate analyses showed that the %divided of CD8⁺ T cells is an independent predictor for PFS (HR: 4.342, 95% CI 1.324-14.245; p = 0.015). The percentages of peripheral Tregs and the degree of chemotherapy or radiotherapy induced lymphopenia negatively correlated with the proliferation of CD8⁺ T cells (p = 0.0225, r = - 0.379; p = 0.0003, r = - 0.464).

CONCLUSION

The present study indicates that SCLC patients have impaired immunity in peripheral blood, and the proliferation potential of circulating CD8⁺ T cells is a significant predicator for PFS.