Carboplatin chemoresistance is associated with CD11b+/Ly6C+ myeloid release and upregulation of TIGIT and LAG3/CD160 exhausted T cells

CD8+ T cell exhaustion and its regulatory mechanisms in the tumor microenvironment: key to the success of immunotherapy

A steady dysfunctional state caused by chronic antigen stimulation in the tumor microenvironment (TME) is known as CD8+ T cell exhaustion. Exhausted-like CD8+ T cells (CD8+ Tex) displayed decreased effector and proliferative capabilities, elevated co-inhibitory receptor generation, decreased cytotoxicity, and changes in metabolism and transcription. TME induces T cell exhaustion through long-term antigen stimulation, upregulation of immune checkpoints, recruitment of immunosuppressive cells, and secretion of immunosuppressive cytokines. CD8+ Tex may be both the reflection of cancer progression and the reason for poor cancer control. The successful outcome of the current cancer immunotherapies, which include immune checkpoint blockade and adoptive cell treatment, depends on CD8+ Tex. In this review, we are interested in the intercellular signaling network of immune cells interacting with CD8+ Tex. These findings provide a unique and detailed perspective, which is helpful in changing this completely unpopular state of hypofunction and intensifying the effect of immunotherapy.

TIGIT Regulates T Cell Inflammation in Airway Inflammatory Diseases

TIGIT, a co-inhibitory receptor found on T cells and NK cells, transmits inhibitory signals upon binding to its ligand. This interaction suppresses the activation of various signaling pathways, leading to functional exhaustion of cells, ultimately dampening excessive inflammatory responses or facilitating immune evasion in tumors. Dysregulated TIGIT expression has been noted in T cells across different inflammatory conditions, exhibiting varying effects based on T cell subsets. TIGIT predominantly restrains the effector function of pro-inflammatory T cells, upholds the suppressive function of regulatory T cells, and influences Tfh maturation. Mechanistically, the IL27-induced transcription factors c-Maf and Blimp-1 are believed to be key regulators of TIGIT expression in T cells. Notably, TIGIT expression in T cells is implicated in lung diseases, particularly airway inflammatory conditions such as lung cancer, obstructive pulmonary disease, interstitial lung disease, sarcoidosis, and COVID-19. This review emphasizes the significance of TIGIT in the context of T cell immunity and airway inflammatory diseases.

Progress of immune checkpoint inhibitors therapy for non-small cell lung cancer with liver metastases

Nearly one-fifth of patients with non-small cell Lung Cancer (NSCLC) will develop liver metastases (LMs), and the overall treatment strategy of LMs will directly affect the survival of patients. However, some retrospective studies have found that patients receiving chemotherapy or targeted therapy have a poorer prognosis once LMs develop. In recent years, multiple randomised controlled trials (RCTS) have shown significant improvements in outcomes for patients with advanced lung cancer following the introduction of immune checkpoint inhibitors (ICIs) compared to conventional chemotherapy. ICIs is safe and effective in patients with LMs, although patients with LMs are mostly underrepresented in randomised clinical trials. However, NSCLC patients with LMs have a significantly worse prognosis than those without LMs when treated with ICIs, and the mechanism by which LMs induce systemic anti-tumour immunity reduction is unknown, so the management of LMs in patients with NSCLC is a clinical challenge that requires more optimised therapies to achieve effective disease control. In this review, we summarised the mechanism of ICIs in the treatment of LMs, the clinical research and treatment progress of ICIs and their combination with other therapies in patients with LMs from NSCLC.

Regulation of T cells by myeloid-derived suppressor cells: emerging immunosuppressor in lung cancer

Myeloid-derived suppressor cells (MDSCs), major components maintaining the immune suppressive microenvironment in lung cancer, are relevant to the invasion, metastasis, and poor prognosis of lung cancer, through the regulation of epithelial-mesenchymal transition, remodeling of the immune microenvironment, and regulation of angiogenesis. MDSCs regulate T-cell immune functions by maintaining a strong immunosuppressive microenvironment and promoting tumor invasion. This raises the question of whether reversing the immunosuppressive effect of MDSCs on T cells can improve lung cancer treatment. To understand this further, this review explores the interactions and specific mechanisms of different MDSCs subsets, including regulatory T cells, T helper cells, CD8 + T cells, natural killer T cells, and exhausted T cells, as part of the lung cancer immune microenvironment. Second, it focuses on the guiding significance confirmed via clinical liquid biopsy and tissue biopsy that different MDSC subsets improve the prognosis of lung cancer. Finally, we conclude that targeting MDSCs through action targets or signaling pathways can help regulate T-cell immune functions and suppress T-cell exhaustion. In addition, immune checkpoint inhibitors targeting MDSCs may serve as a new approach for enhancing the efficiency of immunotherapy and targeted therapy for lung cancer in the future, providing better comprehensive options for lung cancer treatment.

Tumor-derived interleukin-34 creates an immunosuppressive and chemoresistant tumor microenvironment by modulating myeloid-derived suppressor cells in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype characterized by a lack of therapeutic targets. The paucity of effective treatment options motivated a number of studies to tackle this problem. Immunosuppressive cells infiltrated into the tumor microenvironment (TME) of TNBC are currently considered as candidates for new therapeutic targets. Myeloid-derived suppressor cells (MDSCs) have been reported to populate in the TME of TNBC, but their roles in the clinical and biological features of TNBC have not been clarified. This study identified that interleukin-34 (IL-34) released by TNBC cells is a crucial immunomodulator to regulate MDSCs accumulation in the TME. We provide evidence that IL-34 induces a differentiation of myeloid stem cells into monocytic MDSCs (M-MDSCs) that recruits regulatory T (Treg) cells, while suppressing a differentiation into polymorphonuclear MDSCs (PMN-MDSCs). As a result, the increase in M-MDSCs contributes to the creation of an immunosuppressive TME, and the decrease in PMN-MDSCs suppresses angiogenesis, leading to an acquisition of resistance to chemotherapy. Accordingly, blockade of M-MDSC differentiation with an estrogen receptor inhibitor or anti-IL-34 monoclonal antibody suppressed M-MDSCs accumulation causing retardation of tumor growth and restores chemosensitivity of the tumor by promoting PMN-MDSCs accumulation. This study demonstrates previously poorly understood mechanisms of MDSCs-mediated chemoresistance in the TME of TNBC, which is originated from the existence of IL-34, suggesting a new rationale for TNBC treatment.

Targeted Therapy of Interleukin-34 as a Promising Approach to Overcome Cancer Therapy Resistance

Chemotherapy and immunotherapy have markedly improved the management of several malignancies. However, not all cancer patients respond primarily to such therapies, and others can become resistant during treatment. Thus, identification of the factors/mechanisms underlying cancer resistance to such treatments could help develop novel effective therapeutic compounds. Tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), and regulatory T cells (Tregs) are major components of the suppressive tumor microenvironment and are critical drivers of immunosuppression, creating a tumor-promoting and drug-resistant niche. In this regard, therapeutic strategies to tackle immunosuppressive cells are an interesting option to increase anti-tumor immune responses and overcome the occurrence of drug resistance. Accumulating evidence indicates that interleukin-34 (IL-34), a cytokine produced by cancer cells, and/or TAMs act as a linker between induction of a tumor-associated immunosuppressive microenvironment and drug resistance. In this article, we review the current data supporting the role of IL-34 in the differentiation/function of immune suppressive cells and, hence, in the mechanisms leading to therapeutic resistance in various cancers.

Anti-Inflammatory Mechanisms of Dietary Flavones: Tapping into Nature to Control Chronic Inflammation in Obesity and Cancer

Flavones are natural phytochemicals broadly distributed in our diet. Their anti-inflammatory properties provide unique opportunities to control the innate immune system and inflammation. Here, we review the role of flavones in chronic inflammation with an emphasis on their impact on the molecular mechanisms underlying inflammatory diseases including obesity and cancer. Flavones can influence the innate immune cell repertoire restoring the immune landscape. Flavones impinge on NF-κB, STAT, COX-2, or NLRP3 inflammasome pathways reestablishing immune homeostasis. Devoid of adverse side effects, flavones could present alternative opportunities for the treatment and prevention of chronic inflammation that contributes to obesity and cancer.

Translational Learnings in the Development of Chemo-Immunotherapy Combination to Bypass the Cold Tumor Microenvironment in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal cancers, with a 5-year relative survival rate of 5%. The desmoplastic stroma found in the tumor microenvironment of PDAC is suggested to be partly responsible for the resistance to most therapeutic strategies. This review outlines the clinical results obtained with an immune checkpoint inhibitor in PDAC and discusses the rationale to use a combination of chemotherapy and immune checkpoint therapy. Moreover, essential parameters to take into account in designing an efficient combination have been highlighted.

Roles of the Exosomes Derived From Myeloid-Derived Suppressor Cells in Tumor Immunity and Cancer Progression

Tumor immunity is involved in malignant tumor progression. Myeloid-derived suppressor cells (MDSCs) play an irreplaceable role in tumor immunity. MDSCs are composed of immature myeloid cells and exhibit obvious immunomodulatory functions. Exosomes released by MDSCs (MDSCs-Exos) have similar effects to parental MDSCs in regulating tumor immunity. In this review, we provided a comprehensive description of the characteristics, functions and mechanisms of exosomes. We analyzed the immunosuppressive, angiogenesis and metastatic effects of MDSCs-Exos in different tumors through multiple perspectives. Immunotherapy targeting MDSCs-Exos has demonstrated great potential in cancers and non-cancerous diseases.

Identification of Immune-Related Gene Signatures in Lung Adenocarcinoma and Lung Squamous Cell Carcinoma

Accumulating evidence indicates that immunotherapy helped to improve the survival and quality-of-life of patients with lung adenocarcinoma (LUAD) or lung squamous cell carcinoma (LUSC) besides chemotherapy and gene targeting treatment. This study aimed to develop immune-related gene signatures in LUAD and LUSC subtypes, respectively. LUAD and LUSC samples were divided into high- and low-abundance groups of immune cell infiltration (Immunity_H and Immunity_L) based on the abundance of immune cell infiltrations. The distribution of immune cells was significantly different between the high- and low-immunity subtypes in LUAD and LUSC samples. The differentially expressed genes (DEGs) between those two groups in LUAD and LUSC contain some key immune-related genes, such as PDL1, PD1, CTLA-4, and HLA families. The DEGs were enriched in multiple immune-related pathways. Furthermore, the seven-immune-related-gene-signature (CD1B, CHRNA6, CLEC12B, CLEC17A, CLNK, INHA, and SLC14A2) prognostic model-based high- and low-risk groups were significantly associated with LUAD overall survival and clinical characteristics. The eight-immune-related-gene-signature (C4BPB, FCAMR, GRAPL, MAP1LC3C, MGC2889, TRIM55, UGT1A1, and VIPR2) prognostic model-based high- and low-risk groups were significantly associated with LUSC overall survival and clinical characteristics. The prognostic models were tested as good ones by receiver operating characteristic, principal component analysis, univariate and multivariate analysis, and nomogram. The verifications of these two immune-related-gene-signature prognostic models showed consistency in the train and test cohorts of LUAD and LUSC. In addition, patients with LUAD in the low-risk group responded better to immunotherapy than those in the high-risk group. This study revealed two reliable immune-related-gene-signature models that were significantly associated with prognosis and tumor microenvironment cell infiltration in LUAD and LUSC, respectively. Evaluation of the integrated characterization of multiple immune-related genes and pathways could help to predict the response to immunotherapy and monitor immunotherapy strategies.

Pembrolizumab monotherapy versus pembrolizumab plus chemotherapy in patients with non-small-cell lung cancer: A multicenter retrospective trial

Background

Pembrolizumab alone or in combination with chemotherapy is a standard treatment for patients with non‐small‐cell lung cancer (NSCLC) with high programmed death‐ligand 1 (PD‐L1) expression. However, no study has compared the efficacies of these two regimens. Therefore, we aimed to compare the efficacy of pembrolizumab alone and in combination with chemotherapy in NSCLC patients with high PD‐L1 expression.

Methods

We conducted a multicenter retrospective trial involving patients with diagnosed unresectable or recurrent NSCLCs who had received pembrolizumab with or without chemotherapy in the first‐line setting. Patients were divided into monotherapy and combination therapy groups. The progression‐free survival (PFS), overall survival (OS), and response rate (RR) were analyzed and compared between the groups. Clinical characteristics of patients were analyzed to assess their possible relationship with treatment outcomes.

Results

We enrolled 96 patients from five hospitals. Of these, 47 and 49 patients received monotherapy and combination therapy, respectively. The median PFS was 343 and 328 days in the monotherapy and combination therapy groups, respectively (hazard ratio 1.003, p = 0.99). No statistically significant differences were observed in the OS and RR between the two groups. However, in patients with metastases to the liver, lung, adrenal glands, bone, or lymph nodes, the PFS was longer in the monotherapy group than in the combination therapy group.

Conclusion

Although the PFS, OS, and RR were not significantly different between patients treated with pembrolizumab alone and or with pembrolizumab in combination with chemotherapy, patients with NSCLC having metastases to specific sites may benefit more from monotherapy.

Myeloid-derived suppressor cells (MDSCs) in brain cancer: challenges and therapeutic strategies

The most fatal malignancy of the central nervous system (CNS) is glioblastoma. Brain cancer is a 'cold' tumor because of fewer immunoregulatory cells and more immunosuppressive cells. Due to the cold nature of brain cancers, conventional treatments which are used to manage glioma patients show little effectiveness. Glioma patients even showed resistance to immune checkpoint blockade (ICB) and no significant efficacy. It has been shown that myeloid-derived suppressor cells (MDSCs) account for approximately 30-50% of the tumor mass in glioma. This study aimed to review MDSC function in brain cancer, as well as possible treatments and related challenges. In brain cancer and glioma, several differences in the context of MDSCs have been reported, including disagreements about the MDSC subtype that has the most inhibitory function in the brain, or inhibitory function of regulatory B cells (Bregs). There are also serious challenges in treating glioma patients. In addition to the cold nature of glioma, there are reports of an increase in MDSCs following conventional chemotherapy treatments. As a result, targeting MDSCs in combination with other therapies, such as ICB, is essential, and recent studies with the combination therapy approach have shown promising therapeutic effects in brain cancer.

Resveratrol attenuates TNBC lung metastasis by down-regulating PD-1 expression on pulmonary T cells and converting macrophages to M1 phenotype in a murine tumor model

Triple-negative breast cancer (TNBC) is an invasive breast cancer with the characteristics of easy to develop distant metastasis. Immune escape is one of the main reasons for TNBC growth and metastasis. Enhancement of T cell-mediated anti-tumor activity may benefit to inhibit tumor metastasis and improve the efficacy of cancer therapy. As a natural bioactive substance, resveratrol shows potential capability to prevent or suppress the development of a variety of cancers through direct or indirect effects, including immunoregulatory effect. However, whether resveratrol might affect lung metastasis of TNBC, and whether the effect of resveratrol might be associated with resveratrol-regulated immune responses in tumor microenvironment is still unknown. In this study, by using an experimental metastatic mouse 4 T1 tumor model, we identified that resveratrol may suppress TNBC lung metastasis by elevating local anti-tumor immunity. Indeed, an increase in the cytotoxic activity of CD8⁺T cells as well as the levels of type 1 cytokine IFN-γ and IL-2 in the lungs of resveratrol-treated tumor bearing mice were observed. The enhanced CD8⁺T cell activity and Th1 immune responses by resveratrol administration might be related to the down-regulated PD-1 expression on pulmonary CD8⁺T cells and CD4⁺T cells. Resveratrol may also convert macrophages to M1 phenotype in the lungs of tumor bearing mice. However, it seems likely resveratrol has no effect on pulmonary myeloid-derived suppressor cell activation. Our results provide an evidence that resveratrol might be a promising candidate agent for adjuvant therapy in the process of TNBC metastasis.

Kras-driven intratumoral heterogeneity triggers infiltration of M2 polarized macrophages via the circHIPK3/PTK2 immunosuppressive circuit

Intratumoral heterogeneity in lung cancer is essential for evasion of immune surveillance by tumor cells and establishment of immunosuppression. Gathering data reveal that circular RNAs (circRNAs), play a role in the pathogenesis and progression of lung cancer. Particularly Kras-driven circRNA signaling triggers infiltration of myeloid-associated tumor macrophages in lung tumor microenvironment thus establishing immune deregulation, and immunosuppression but the exact pathogenic mechanism is still unknown. In this study, we investigate the role of oncogenic Kras signaling in circRNA-related immunosuppression and its involvement in tumoral chemoresistance. The expression pattern of circRNAs HIPK3 and PTK2 was determined using quantitative polymerase chain reaction (qPCR) in lung cancer patient samples and cell lines. Apoptosis was analyzed by Annexin V/PI staining and FACS detection. M2 macrophage polarization and MDSC subset analysis (Gr1^-/CD11b^-, Gr1^-/CD11b⁺) were determined by flow cytometry. Tumor growth and metastatic potential were determined in vivo in C57BL/6 mice. Findings reveal intra-epithelial CD163⁺/CD206⁺ M2 macrophages to drive Kras immunosuppressive chemoresistance through myeloid differentiation. In particular, monocytic MDSC subsets Gr1^-/CD11b^-, Gr1^-/CD11b⁺ triggered an M2-dependent immune response, creating an immunosuppressive tumor-promoting network via circHIPK3/PTK2 enrichment. Specifically, upregulation of exosomal cicHIPK3/PTK2 expression prompted Kras-driven intratumoral heterogeneity and guided lymph node metastasis in C57BL/6 mice. Consequent co-inhibition of circPTK2/M2 macrophage signaling suppressed lung tumor growth along with metastatic potential and prolonged survival in vivo. Taken together, these results demonstrate the key role of myeloid-associated macrophages in sustaining lung immunosuppressive neoplasia through circRNA regulation and represent a potential therapeutic target for clinical intervention in metastatic lung cancer.

Conjugation with nanodiamonds via hydrazone bond fundamentally alters intracellular distribution and activity of doxorubicin

Doxorubicin (DOX) has been widely incorporated in various delivery forms for tareted treatment of malignant tumors such as triple-negative breast cancer (TNBC), with numerous studies reporting higher therapeutic efficacy and lower toxicity at the same time. However, little attention has been paid to whether DOX in a delivery form acts with the same actions and processes as in free form at the cellular level. This question was investigated in the present study wherein DOX conjugated with polyglycerol-coated nanodiamonds through the pH-sensitive hydrazone bond (Nano-DOX) was compared with DOX in free form on the 4T1 mouse TNBC model. We first found Nano-DOX to have a distinct intracellular distribution profile from DOX. Internalized Nano-DOX mainly stayed in the lysosomes slowly releasing DOX into the cytoplasm and then the nucleus whereas DOX displayed both nuclear and lysosomal distribution after cell uptake. Next, Nano-DOX was shown to induce endoplasmic reticulum (ER) stress without substantial DNA damage while DOX caused massive DNA damage as well as ER stress. Consequently, Nano-DOX only caused minimal activation of pro-inflammatory signaling mediated by MAPK/ERK, NF-κB and STAT3 as seen in response to DOX-inflicted DNA damage. Consistently, DOX-induced activities of ABC transporters, CXCL-1, GM-CSF and IL-6, which are tumor protective events downstream to the pro-inflammatory signaling, were also minimal in Nano-DOX-treated cancer cells. These findings are compelling proof that a chemotherapy in nano form can have distinct intracellular pharmacokinetics from its free from, which can result in altered cellular effects of the drug. Implications of these findings are discussed with an emphasis on nano-drug design, tumor pharmacology and chemoresistance.

Distinct Molecular Subtypes of Diffuse Large B Cell Lymphoma Patients Treated with Rituximab-CHOP Are Associated with Different Clinical Outcomes and Molecular Mechanisms

Objective

Our purpose was to characterize distinct molecular subtypes of diffuse large B cell lymphoma (DLBCL) patients treated with rituximab-CHOP (R-CHOP).

Methods

Two gene expression datasets of R-CHOP-treated DLBCL patients were downloaded from GSE10846 (n = 233, training set) and GSE31312 (n = 470, validation set) datasets. Cluster analysis was presented via the ConsensusClusterPlus package in R. Using the limma package, differential expression analysis was utilized to identify feature genes. Kaplan-Meier survival analysis was presented to compare the differences in the prognosis between distinct molecular subtypes. Correlation between molecular subtypes and clinical features was analyzed. Based on the sets of highly expressed genes, biological functions were explored by gene set enrichment analysis (GSEA). Several feature genes were validated in the molecular subtypes via qRT-PCR and western blot.

Results

DLBCL samples were clustered into two molecular subtypes. Samples in subtype I displayed poorer overall survival time in the training set (p < 0.0001). Consistently, patients in subtype I had shorter overall survival (p = 0.0041) and progression-free survival time (p < 0.0001) than those in subtype II. Older age, higher stage, and higher international prognostic index (IPI) were found in subtype I. In subtype I, T cell activation, lymphocyte activation, and immune response were distinctly enriched, while cell adhesion, migration, and motility were significantly enriched in subtype II. T cell exhaustion-related genes including TIM3 (p < 0.001), PD-L1 (p < 0.0001), LAG3 (p < 0.0001), CD160 (p < 0.001), and CD244 (p < 0.001) were significantly highly expressed in subtype I than subtype II.

Conclusion

Two molecular subtypes were constructed in DLBCL, which were characterized by different clinical outcomes and molecular mechanisms. Our findings may offer a novel insight into risk stratification and prognosis prediction for DLBCL patients.

New Insights into the Multifaceted Role of Myeloid-Derived Suppressor Cells (MDSCs) in High-Grade Gliomas: From Metabolic Reprograming, Immunosuppression, and Therapeutic Resistance to Current Strategies for Targeting MDSCs

Cancer cells “hijack” host immune cells to promote growth, survival, and metastasis. The immune microenvironment of high-grade gliomas (HGG) is a complex and heterogeneous system, consisting of diverse cell types such as microglia, bone marrow-derived macrophages (BMDMs), myeloid-derived suppressor cells (MDSCs), dendritic cells, natural killer (NK) cells, and T-cells. Of these, MDSCs are one of the major tumor-infiltrating immune cells and are correlated not only with overall worse prognosis but also poor clinical outcomes. Upon entry from the bone marrow into the peripheral blood, spleen, as well as in tumor microenvironment (TME) in HGG patients, MDSCs deploy an array of mechanisms to perform their immune and non-immune suppressive functions. Here, we highlight the origin, function, and characterization of MDSCs and how they are recruited and metabolically reprogrammed in HGG. Furthermore, we discuss the mechanisms by which MDSCs contribute to immunosuppression and resistance to current therapies. Finally, we conclude by summarizing the emerging approaches for targeting MDSCs alone as a monotherapy or in combination with other standard-of-care therapies to improve the current treatment of high-grade glioma patients.

Tumor-infiltrating CD8+ T cell antitumor efficacy and exhaustion: molecular insights

Host immunity has an essential role in the clinical management of cancers. Therefore, it is advantageous to choose therapies that can promote tumor cell death and concurrently boost host immunity. The dynamic tumor microenvironment (TME) determines whether an antineoplastic drug will elicit favorable or disparaging immune responses from tumor-infiltrating lymphocytes (TILs). CD8+ T cells are one of the primary tumor-infiltrating immune cells that deliver antitumor responses. Here, we review the influence of various factors in the TME on CD8+ T cell exhaustion and survival, and possible strategies for restoring CD8+ T cell effector function through immunotherapy.

Treg-dependent immunosuppression triggers effector T cell dysfunction via the STING/ILC2 axis

Lung cancer remains the leading cause of cancer-related deaths and despite extensive research, the survival rate of lung cancer patients remains significantly low. Recent data reveal that aberrant Kras signaling drives regulatory T cells (Tregs) present in lung tumor microenvironment to establish immune deregulation and immunosuppression but the exact pathogenic mechanism is still unknown. In this study, we investigate the role of oncogenic Kras in Treg-related immunosuppression and its involvement in tumor-associated metabolic reprogramming. Findings reveal Tregs to prompt GATA3/NOS2-related immunosuppression via STING inhibition which triggers a decline in CD4⁺ T infiltration, and a subsequent increase in lung metastatic burden. Enhanced Treg expression was also associated with low T/MDSC ratio through restriction of CD8⁺CD44⁺CD62L^- T effector cells, contributing to a tumor-promoting status. Specifically, TIM3⁺/LAG3⁺ Tregs prompted Kras-related immunosuppressive chemoresistance and were associated with T cell dysfunction. This Treg-dependent immunosuppression correlated with CD8 T cell exhaustion phenotype and ILC2 augmentation in mice. Moreover, enhanced Treg expression promoted activation-induced cell death (AICD) of T lymphocytes and guided lymph node metastasis in vivo. Overall, these findings demonstrate the multifaceted roles of Tregs in sustaining lung immunosuppressive neoplasia through tumor microenvironment remodeling and provide new opportunities for effective metastasis inhibition, especially in chemoresistant tumors.

Clinical significance of LSECtin and its association with PVR in non-small-cell lung cancer patients

BACKGROUND

Liver and lymph node sinusoidal endothelial cell C-type lectin (LSECtin) is one of the new generation immune checkpoint ligand molecules and plays an important role in the immune environment. Poliovirus receptor (PVR), as another immunosuppression-related molecule, is upregulated in various malignant tumors. However, the clinical value of LSECtin and the correlation of LSECtin with PVR in non-small-cell lung cancer (NSCLC) remain to be elucidated. In this study, a retrospective study was performed to address these issues.

METHODS

This retrospective study included 98 patients with NSCLC. Immunohistochemistry (IHC) was used to detect the expression of LSECtin and PVR in the paraffin-embedded tumor tissue specimens. LSECtin was analyzed for associations with the survival rate and overall survival (OS) of the subjects. The mRNA expression of LSECtin and PVR was assessed using the expression data from The Cancer Genome Atlas (TCGA) database. Clinical characteristics, prognosis, and the expression of LSECtin and PVR were included in the statistical analysis.

RESULTS

High positive rates of LSECtin were found in the patients with NSCLC who were nonsmokers, at advanced stages, or had lung adenocarcinoma. Patients with positive LSECtin expression had a significantly lower survival rate (P=0.008) and shorter OS (P=0.017) than those with negative LSECtin. Significant correlation was found between the LSECtin and PVR expression in the patients with NSCLC (P<0.001).

CONCLUSIONS

The increased expression of LSECtin was related to the poor prognosis of patients with NSCLC after tumor resection and has the potential value for predicting the prognosis of these patients. The positive correlation between LSECtin and PVR in NSCLC provides a theoretical basis for the future combination therapy of immune checkpoints.

Immunogenic Cell Death and Elimination of Immunosuppressive Cells: A Double-Edged Sword of Chemotherapy

Chemotherapy is initially used to kill proliferative cells. In the current area of emerging immunotherapy, chemotherapies have shown their ability to modulate the tumor micro environment and immune response. We focus here on two main effects: first, immunogenic cell death, defined as a form of regulated cell death (RCD) that is sufficient to activate an adaptive immune response in immunocompetent hosts; and second, the depletion of suppressive cells, known to play a major role in immune escape and resistance to immunotherapy. In this review, we present a review of different classically used chemotherapies focusing on this double effect on immunity. These immunological effects of chemotherapy could be exploited to promote efficacy of immunotherapy. Broadening our understanding will make it possible to provide rationales for the combination of chemoimmunotherapy in early clinical trials.

Exosomal lncRNA PCAT-1 promotes Kras-associated chemoresistance via immunosuppressive miR-182/miR-217 signaling and p27/CDK6 regulation

Immunosuppressive chemoresistance is a major burden in lung cancer. Recent data reveal that long noncoding RNAs (lncRNAs) present in the lung tumor microenvironment are implicated in chemoresistant-related immune deregulation, and metastasis but their exact pathogenic role is still unknown. In this study, we investigate the role of lncRNA PCAT-1 in chemoresistant immunosuppression and its involvement in tumor stroma remodeling. Findings reveal PCAT-1 to regulate Kras-related lung chemoresistance through increased expression of the immunosuppressive micrornas miR-182/miR217 in lung tissues, thus promoting a pre-metastatic niche formation and a subsequent increase in lung metastatic burden. Elevated expression of PCAT-1 negative regulates p27/CDK6 expression by inducing G₀/G₁ cell cycle arrest through AMPK augmentation, contributing to a tumor-promoting status. Furthermore, PCAT-1 triggered fibroblast differentiation followed by CAF/myofibroblast secretion in TME triggering a CD133/SOX2-related stem cell phenotype. Subsequent PCAT-1 knockdown impaired CAF-mediated stromal activation, and reversed chemoresistance and tumor growth in vivo. Overall, these findings demonstrate the versatile roles of PCAT-1 in sustaining lung immunosuppressive neoplasia through tumor microenvironment remodeling and provide new opportunities for effective metastasis inhibition, especially in chemoresistant tumors.