Mechanisms and functional significance of tumour-induced dendritic-cell defects

Dysfunction of dendritic cells in tumor microenvironment and immunotherapy

Dendritic cells (DCs) comprise diverse cell populations that play critical roles in antigen presentation and triggering immune responses in the body. However, several factors impair the immune function of DCs and may promote immune evasion in cancer. Understanding the mechanism of DC dysfunction and the diverse functions of heterogeneous DCs in the tumor microenvironment (TME) is critical for designing effective strategies for cancer immunotherapy. Clinical applications targeting DCs summarized in this report aim to improve immune infiltration and enhance the biological function of DCs to modulate the TME to prevent cancer cells from evading the immune system. Herein, factors in the TME that induce DC dysfunction, such as cytokines, hypoxic environment, tumor exosomes and metabolites, and co-inhibitory molecules, have been described. Furthermore, several key signaling pathways involved in DC dysfunction and signal-relevant drugs evaluated in clinical trials were identified. Finally, this review provides an overview of current clinical immunotherapies targeting DCs, especially therapies with proven clinical outcomes, and explores future developments in DC immunotherapies.

Non-Coding RNA in Tumor Cells and Tumor-Associated Myeloid Cells-Function and Therapeutic Potential

The RNA world is wide, and besides mRNA, there is a variety of other RNA types, such as non-coding (nc)RNAs, which harbor various intracellular regulatory functions. This review focuses on small interfering (si)RNA and micro (mi)RNA, which form a complex network regulating mRNA translation and, consequently, gene expression. In fact, these RNAs are critically involved in the function and phenotype of all cells in the human body, including malignant cells. In cancer, the two main targets for therapy are dysregulated cancer cells and dysfunctional immune cells. To exploit the potential of mi- or siRNA therapeutics in cancer therapy, a profound understanding of the regulatory mechanisms of RNAs and following targeted intervention is needed to re-program cancer cells and immune cell functions in vivo. The first part focuses on the function of less well-known RNAs, including siRNA and miRNA, and presents RNA-based technologies. In the second part, the therapeutic potential of these technologies in treating cancer is discussed, with particular attention on manipulating tumor-associated immune cells, especially tumor-associated myeloid cells.

Immunologic tumor microenvironment modulators for turning cold tumors hot

Tumors can be classified into distinct immunophenotypes based on the presence and arrangement of cytotoxic immune cells within the tumor microenvironment (TME). Hot tumors, characterized by heightened immune activity and responsiveness to immune checkpoint inhibitors (ICIs), stand in stark contrast to cold tumors, which lack immune infiltration and remain resistant to therapy. To overcome immune evasion mechanisms employed by tumor cells, novel immunologic modulators have emerged, particularly ICIs targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1/programmed death-ligand 1(PD-1/PD-L1). These agents disrupt inhibitory signals and reactivate the immune system, transforming cold tumors into hot ones and promoting effective antitumor responses. However, challenges persist, including primary resistance to immunotherapy, autoimmune side effects, and tumor response heterogeneity. Addressing these challenges requires innovative strategies, deeper mechanistic insights, and a combination of immune interventions to enhance the effectiveness of immunotherapies. In the landscape of cancer medicine, where immune cold tumors represent a formidable hurdle, understanding the TME and harnessing its potential to reprogram the immune response is paramount. This review sheds light on current advancements and future directions in the quest for more effective and safer cancer treatment strategies, offering hope for patients with immune-resistant tumors.

Hepatocytes coordinate immune evasion in cancer via release of serum amyloid A proteins

T cell infiltration into tumors is a favorable prognostic feature, but most solid tumors lack productive T cell responses. Mechanisms that coordinate T cell exclusion are incompletely understood. Here we identify hepatocyte activation via interleukin-6/STAT3 and secretion of serum amyloid A (SAA) proteins 1 and 2 as important regulators of T cell surveillance of extrahepatic tumors. Loss of STAT3 in hepatocytes or SAA remodeled the tumor microenvironment with infiltration by CD8+ T cells, while interleukin-6 overexpression in hepatocytes and SAA signaling via Toll-like receptor 2 reduced the number of intratumoral dendritic cells and, in doing so, inhibited T cell tumor infiltration. Genetic ablation of SAA enhanced survival after tumor resection in a T cell-dependent manner. Likewise, in individuals with pancreatic ductal adenocarcinoma, long-term survivors after surgery demonstrated lower serum SAA levels than short-term survivors. Taken together, these data define a fundamental link between liver and tumor immunobiology wherein hepatocytes govern productive T cell surveillance in cancer.

Electrochemical immunosensing of tumor markers

The rising incidence and mortality rates of cancer have led to a growing need for precise and prompt early diagnostic approaches to effectively combat this disease. However, traditional methods employed for detecting tumor cells, such as histopathological and immunological techniques, are often associated with complex procedures, high analytical expenses, elevated false positive rates, and a dependence on experienced personnel. Tracking tumor markers is recognized as one of the most effective approaches for early detection and prognosis of cancer. While onco-biomarkers can also be produced in normal circumstances, their concentration is significantly elevated when tumors are present. By monitoring the levels of these markers, healthcare professionals can obtain valuable insights into the presence, progression, and response to treatment of cancer, aiding in timely diagnosis and effective management. This review aims to provide researchers with a comprehensive overview of the recent advancements in tumor markers using electrochemical immunosensors. By highlighting the latest developments in this field, researchers can gain a general understanding of the progress made in the utilization of electrochemical immunosensors for detecting tumor markers. Furthermore, this review also discusses the current limitations associated with electrochemical immunosensors and offers insights into paving the way for further improvements and advancements in this area of research.

Nanoparticles in tumor microenvironment remodeling and cancer immunotherapy

Cancer immunotherapy and vaccine development have significantly improved the fight against cancers. Despite these advancements, challenges remain, particularly in the clinical delivery of immunomodulatory compounds. The tumor microenvironment (TME), comprising macrophages, fibroblasts, and immune cells, plays a crucial role in immune response modulation. Nanoparticles, engineered to reshape the TME, have shown promising results in enhancing immunotherapy by facilitating targeted delivery and immune modulation. These nanoparticles can suppress fibroblast activation, promote M1 macrophage polarization, aid dendritic cell maturation, and encourage T cell infiltration. Biomimetic nanoparticles further enhance immunotherapy by increasing the internalization of immunomodulatory agents in immune cells such as dendritic cells. Moreover, exosomes, whether naturally secreted by cells in the body or bioengineered, have been explored to regulate the TME and immune-related cells to affect cancer immunotherapy. Stimuli-responsive nanocarriers, activated by pH, redox, and light conditions, exhibit the potential to accelerate immunotherapy. The co-application of nanoparticles with immune checkpoint inhibitors is an emerging strategy to boost anti-tumor immunity. With their ability to induce long-term immunity, nanoarchitectures are promising structures in vaccine development. This review underscores the critical role of nanoparticles in overcoming current challenges and driving the advancement of cancer immunotherapy and TME modification.

cGAS-STING pathway mediates activation of dendritic cell sensing of immunogenic tumors

Type I interferons (IFN-I) play pivotal roles in tumor therapy for three decades, underscoring the critical importance of maintaining the integrity of the IFN-1 signaling pathway in radiotherapy, chemotherapy, targeted therapy, and immunotherapy. However, the specific mechanism by which IFN-I contributes to these therapies, particularly in terms of activating dendritic cells (DCs), remains unclear. Based on recent studies, aberrant DNA in the cytoplasm activates the cyclic GMP-AMP synthase (cGAS)- stimulator of interferon genes (STING) signaling pathway, which in turn produces IFN-I, which is essential for antiviral and anticancer immunity. Notably, STING can also enhance anticancer immunity by promoting autophagy, inflammation, and glycolysis in an IFN-I-independent manner. These research advancements contribute to our comprehension of the distinctions between IFN-I drugs and STING agonists in the context of oncology therapy and shed light on the challenges involved in developing STING agonist drugs. Thus, we aimed to summarize the novel mechanisms underlying cGAS-STING-IFN-I signal activation in DC-mediated antigen presentation and its role in the cancer immune cycle in this review.

Enhanced antitumour response of gold nanostar-mediated photothermal therapy in combination with immunotherapy in a mouse model of colon carcinoma

OBJECTIVES

This study investigated the potential of combining PTT with dendritic cell (DC)-based immunotherapy and anti-PD-L1 immune checkpoint blockade (ICB) therapy against colorectal cancer and elucidated the underlying mechanisms.

METHODS

The CT26 tumour-bearing mice were divided into seven treatment groups: control, atezolizumab (A), dendritic cells (DC), pAuNSs-mediated PTT (PTT), PTT combined with atezolizumab (PTT + A), PTT combined with dendritic cells (PTT + DC), and PTT combined with dendritic cells and atezolizumab (PTT + DC + A). Therapeutic efficacy was monitored.

RESULTS

PTT upregulated most immune cell membrane receptor genes, including PD-L1, and downregulated genes associated with antigen presentation and T cell activation. Although the PTT + A and PTT + DC treatments showed partial tumour growth retardation, the combination of PTT with DCs and atezolizumab (PTT + DC + A) exhibited the most significant antitumour effect, with a complete remission rate of 50% and prolonged survival. On day 14, tumour samples from non-responsive mice revealed insufficient recruitment of T cells as the reason for uncured tumours. Notably, mice cured with PTT + DC and PTT + DC + A treatments showed no detectable lung nodules.

CONCLUSION

This study demonstrated that the combination of PTT with DC-based immunotherapy and atezolizumab effectively overcomes the non-sensitive nature of CT26 tumours. These findings highlight the potential of this combination approach for colorectal cancer treatment.

Exosome regulation of immune response mechanism: Pros and cons in immunotherapy

Due to its multiple features, including the ability to orchestrate remote communication between different tissues, the exosomes are the extracellular vesicles arousing the highest interest in the scientific community. Their size, established as an average of 30-150 nm, allows them to be easily uptaken by most cells. According to the type of cells-derived exosomes, they may carry specific biomolecular cargoes used to reprogram the cells they are interacting with. In certain circumstances, exosomes stimulate the immune response by facilitating or amplifying the release of foreign antigens-killing cells, inflammatory factors, or antibodies (immune activation). Meanwhile, in other cases, they are efficiently used by malignant elements such as cancer cells to mislead the immune recognition mechanism, carrying and transferring their cancerous cargoes to distant healthy cells, thus contributing to antigenic invasion (immune suppression). Exosome dichotomic patterns upon immune system regulation present broad advantages in immunotherapy. Its perfect comprehension, from its early biogenesis to its specific interaction with recipient cells, will promote a significant enhancement of immunotherapy employing molecular biology, nanomedicine, and nanotechnology.

Immune Escape Strategies in Head and Neck Cancer: Evade, Resist, Inhibit, Recruit

Head and neck cancers (HNCs) arise from the mucosal lining of the aerodigestive tract and are often associated with alcohol use, tobacco use, and/or human papillomavirus (HPV) infection. Over 600,000 new cases of HNC are diagnosed each year, making it the sixth most common cancer worldwide. Historically, treatments have included surgery, radiation, and chemotherapy, and while these treatments are still the backbone of current therapy, several immunotherapies have recently been approved by the Food and Drug Administration (FDA) for use in HNC. The role of the immune system in tumorigenesis and cancer progression has been explored since the early 20th century, eventually coalescing into the current three-phase model of cancer immunoediting. During each of the three phases-elimination, equilibrium, and escape-cancer cells develop and utilize multiple strategies to either reach or remain in the final phase, escape, at which point the tumor is able to grow and metastasize with little to no detrimental interference from the immune system. In this review, we summarize the many strategies used by HNC to escape the immune system, which include ways to evade immune detection, resist immune cell attacks, inhibit immune cell functions, and recruit pro-tumor immune cells.

In vivo targeting of a tumor-antigen encoded DNA vaccine to dendritic cells in combination with tumor-selective chemotherapy eradicates established mouse melanoma

Despite remarkable progress during the past decade, eradication of established tumors by targeted cancer therapy and cancer immunotherapy remains an uphill task. Herein, we report on a combination approach for eradicating established mouse melanoma. Our approach employs the use of tumor selective chemotherapy in combination with in vivo dendritic cell (DC) targeted DNA vaccination. Liposomes of a newly synthesized lipopeptide containing a previously reported tumor-targeting CGKRK-ligand covalently grafted in its polar head-group region were used for tumor selective delivery of cancer therapeutics. Liposomally co-loaded STAT3siRNA and WP1066 (a commercially available inhibitor of the JAK2/STAT3 pathway) were used as cancer therapeutics. In vivo targeting of a melanoma antigen (MART-1) encoded DNA vaccine (p-CMV-MART1) to dendritic cells was accomplished by complexing it with a previously reported mannose-receptor selective in vivo DC-targeting liposome. Liposomes of the CGKRK-lipopeptide containing encapsulated FITC-labeled siRNA, upon intravenous administration in B16F10 melanoma bearing mice, showed remarkably higher accumulation in tumors 24 h post i.v. treatment, compared to their degree of accumulation in other body tissues including the lungs, liver, kidneys, spleen and heart. Importantly, the findings in tumor growth inhibition studies revealed that only in vivo DC-targeted genetic immunization or only tumor-selective chemotherapy using the presently described systems failed to eradicate the established mouse melanoma. The presently described combination approach is expected to find future applications in combating various malignancies (with well-defined surface antigens).

Hypoxia induces immunosuppression, metastasis and drug resistance in pancreatic cancers

Pancreatic cancer is one of the common malignant tumors of the digestive system and is known as the "king of cancers". It is extremely difficult to diagnose at an early stage, the disease progresses rapidly, and the effect of chemotherapy and radiotherapy is poor, so the prognosis of pancreatic cancer patients is very poor. Numerous studies have suggested that hypoxia is closely related to the development and progression of pancreatic cancer. Inadequate blood supply and desmoplasia in the microenvironment of pancreatic cancer can result in its extreme hypoxia. This hypoxic microenvironment can further contribute to angiogenesis and desmoplasia. Hypoxia is mediated by the complex hypoxia inducible factor (HIF) signaling pathway and plays an important role in the formation of a highly immunosuppressive microenvironment and the metastasis of pancreatic cancer. Further work on the hypoxic microenvironment will help clarify the specific mechanisms of the role of hypoxia in pancreatic cancer and provide a basis for the realization of hypoxia-targeted therapeutic and diagnostic strategies.

Targeted therapy for head and neck squamous cell carcinoma microenvironment

Head and neck squamous cell carcinoma (HNSCC) originates from the squamous epithelium of the oral cavity, oropharynx, larynx, and hypopharynx. HNSCC in the oral cavity and larynx is strongly associated with tobacco smoking and alcohol consumption, while oropharyngeal cancer is increasingly attributed to infection by human papillomavirus (HPV), particularly HPV-16. The tumor microenvironment (TME) is a complex network of cancer cells, immune cells, stromal cells, surrounding blood vessels, and signaling molecules, and plays a critical role in tumor cell survival, invasion, and recurrence. Therefore, it is critical to elucidate the molecular basis of the interaction between tumor cells and the TME in order to develop innovative anti-cancer therapeutic strategies.

Primary and acquired resistance to first-line therapy for clear cell renal cell carcinoma

The introduction of first-line combinations had improved the outcomes for metastatic renal cell carcinoma (mRCC) compared to sunitinib. However, some patients either have inherent resistance or develop resistance as a result of the treatment. Depending on the kind of therapy employed, many factors underlie resistance to systemic therapy. Angiogenesis and the tumor immune microenvironment (TIME), nevertheless, are inextricably linked. Although angiogenesis and the manipulation of the tumor microenvironment are linked to hypoxia, which emerges as a hallmark of renal cell carcinoma (RCC) pathogenesis, it is only one of the potential elements involved in the distinctive intra- and inter-tumor heterogeneity of RCC that is still dynamic. We may be able to more correctly predict therapy response and comprehend the mechanisms underlying primary or acquired resistance by integrating tumor genetic and immunological markers. In order to provide tools for patient selection and to generate hypotheses for the development of new strategies to overcome resistance, we reviewed the most recent research on the mechanisms of primary and acquired resistance to immune checkpoint inhibitors (ICIs) and tyrosine kinase inhibitors (TKIs) that target the vascular endothelial growth factor receptor (VEGFR).We can choose patients' treatments and cancer preventive strategies using an evolutionary approach thanks to the few evolutionary trajectories that characterize ccRCC.

Dendritic Cell-Based Immunity: Screening of Dendritic Cell Subsets in Breast Cancer-Bearing Mice

Background

Breast cancer (BC) is the most devastating disease, particularly the lethal invasive form. It is the most underlying cause of death among women worldwide. The expansion of BC is controlled by a variety of alterations in the tumor cells themselves, in addition to the state of the immune system, which has a direct influence on the tumor microenvironment. Numerous receptors expressed by T-cells interact with ligands on antigen-presenting cells to provide activation signals results in mounting effector anti-tumor T-cell responses. On the other hand, there is a dearth of information about the actual interactions and reactions of T-cells and dendritic cells (DCs) all through the progression of tumor development.

Aim

Immune system response against BC was investigated through tumor induction in mice. The size and volume of the tumor were calculated. Moreover, the phenotypical profile of T-cells and DCs from lymph nodes (LN) and spleens of BC-bearing mice was investigated. In addition, the levels of Transforming growth factor-β, Interferon-gamma (IFN-γ), Interleukin IL-2, IL-10, IL-4, IL-12, and tumor necrosis factor (TNF)-α were determined.

Materials and Methods

MDA231 cells were utilized to induce BC in 30 white BALB/C mice, whereas the other 30 mice acted as healthy controls and were not treated with any cancer-causing agents. The impact of malignancy was evaluated using flow cytometry based on the marking surface molecules, as well as the titer of specific cytokines of the mice's LN culture using the ELISA method. These cytokines included transforming growth factor-β (TGF-β), IFN-γ, IL-2, IL -10, IL -4, IL -12, and TNF-α.

Results

The findings showed that the maturation of DCs was inhibited, followed by an accumulation of immature DCs. These immature DCs increase the release of TGF-β and cytokines like IL-10 and inhibit the release of IFN-γ and IL-12 in the culture supernatant of nodal lymph and spleen suspension of BC-bearing mice compared to control. In addition, there was a low expression of CD80 and CD86 on DCs, which indicates a low maturation process.

Conclusion

According to the findings, the tumor microenvironment may have been responsible for preventing the maturation of DCs. This, in turn, weakened the immune response and facilitated the ability of the tumor to proliferate. Furthermore, the tumor microenvironment increased the number of immature DCs by inhibiting their stimulation by overexpression of TGF-β-produced by regulatory T lymphocytes and stimulation of tumor cells. In addition, the tumor microenvironment stimulated the secretion of cytokines such as IL-10, and CD4 and decreased the secretion of IFN-γ-and IL-12 in tumor-induced mice cultured LN and spleen.

Discovery of a novel dual-targeting D-peptide to block CD24/Siglec-10 and PD-1/PD-L1 interaction and synergize with radiotherapy for cancer immunotherapy

BACKGROUND

Aside from immune checkpoint inhibitors targeting programmed cell death protein 1 (PD-1) and programmed death ligand 1 (PD-L1), intervention of CD47/Sirpα mediated 'don't eat me' signal between macrophage and tumor cell is considered as a promising therapeutic approach for cancer immunotherapy. Compared with CD47, the novel immune checkpoint CD24/Siglec-10 can also deliver 'don't eat me' signal and CD24 shows much lower expression level in normal tissue which might avoid unwanted side effects.

METHODS

Cell-based phage display biopanning and D-amino acid modification strategy were used to identify the CD24/Siglec-10 blocking peptide. Cell-based blocking assay and microscale thermophoresis assay were used to validate the blocking and binding activities of the peptide. Phagocytosis and co-culture assays were used to explore the in vitro function of the peptide. Flow cytometry was performed to assess the immune microenvironment after the peptide treatment in vivo.

RESULTS

A CD24/Siglec-10 blocking peptide (CSBP) with hydrolysis-resistant property was identified. Surprisingly, we found that CSBP could not only block the interaction of CD24/Siglec-10 but also PD-1/PD-L1. CSBP could induce the phagocytosis of tumor cell by both the macrophages and monocytic myeloid-derived suppressor cells (M-MDSCs), which can further activate CD8⁺ T cells. Besides, combination of radiotherapy and CSBP synergistically reduced tumor growth and altered the tumor microenvironment in both anti-PD-1-responsive MC38 and anti-PD-1-resistant 4T1 tumor models.

CONCLUSIONS

In summary, this is the first CD24/Siglec-10 blocking peptide which blocked PD-1/PD-L1 interaction as well, functioned via enhancing the phagocytosis of tumor cells by macrophages and M-MDSCs, and elevating the activity of CD8⁺ T cells for cancer immunotherapy.

Investigating the spatial interaction of immune cells in colon cancer

The intricate network of interactions between cells and molecules in the tumor microenvironment creates a heterogeneous ecosystem. The proximity of the cells and molecules to their activators and inhibitors is essential in the progression of tumors. Here, we develop a system of partial differential equations coupled with linear elasticity to investigate the effects of spatial interactions on the tumor microenvironment. We observe interesting cell and cytokine distribution patterns, which are heavily affected by macrophages. We also see that cytotoxic T cells get recruited and suppressed at the site of macrophages. Moreover, we observe that anti-tumor macrophages reorganize the patterns in favor of a more spatially restricted cancer and necrotic core. Furthermore, the adjoint-based sensitivity analysis indicates that the most sensitive model's parameters are directly related to macrophages. The results emphasize the widely acknowledged effect of macrophages in controlling cancer cells population and spatially arranging cells in the tumor microenvironment.

Dichotomous Nitric Oxide–Dependent Post-Translational Modifications of STAT1 Are Associated with Ipilimumab Benefits in Melanoma

Although Ipilimumab (anti-CTLA-4) is FDA-approved for stage III/IV melanoma adjuvant treatment, it is not used clinically in first-line therapy, given the superior relapse-free survival (RFS)/toxicity benefits of anti-PD-1 therapy. However, it is important to understand anti-CTLA-4’s mechanistic contribution to combination anti-PD-1/CTLA-4 therapy and investigate anti-CTLA-4 therapy for BRAF-wild type melanoma cases reresected after previous adjuvant anti-PD-1 therapy. Our group published that nitric oxide (NO) increased within the immune effector cells among patients with longer RFS after adjuvant ipilimumab, whereas NO increased within the immune suppressor cells among patients with shorter RFS. Herein, we measured the post-translational modifications of STAT1 (nitration-nSTAT1 and phosphorylation-pSTAT1) that are important for regulating its activity via flow cytometry and mass spectrometry approaches. PBMCs were analyzed from 35 patients undergoing adjuvant ipilimumab treatment. Shorter RFS was associated with higher pSTAT1 levels before (p = 0.007) and after (p = 0.036) ipilimumab. Ipilimumab-treated patients with high nSTAT1 levels before and after therapy in PBMCs experienced decreased RFS, but the change in nSTAT1 levels before and after ipilimumab therapy was associated with longer RFS (p = 0.01). The measurement of post-translational modifications in STAT1 may distinguish patients with prolonged RFS from ipilimumab and provide mechanistic insight into responses to ipilimumab combination regimens.

Targeting STING Activation by Antigen-Inspired MnO2 Nanovaccines Optimizes Tumor Radiotherapy

Immune checkpoint blockers therapy can improve the radiotherapy-induced immunosuppression by enhancing interferon secretion, but still suffer from low clinical response rate and potential adverse effects. Mn²⁺ -mediated activation of interferon gene stimulator (STING) pathway provides an alternative for combination radioimmunotherapy of tumor. However, it is still a challenge for specific delivery of Mn²⁺ to innate immune cells and targeting activation of STING pathway. Herein, a novel antigen-inspired MnO₂ nanovaccine is fabricated as Mn²⁺ source and functionalized with mannose, enabling it to target innate immune cells to activate the STING pathway. Meanwhile, the release of Mn²⁺ in the intracellular lysosomes can also be for magnetic resonance imaging to monitor the dynamic distribution of nanovaccines in vivo. The targeting activation of STING pathway can enhance radiotherapy-induced immune responses for inhibiting local and distant tumors, and resisting tumor metastasis. The study proposes an optimized radiotherapy strategy through targeting STING activation of antigen-inspired nanovaccines.

Concomitant inhibition of PPARγ and mTORC1 induces the differentiation of human monocytes into highly immunogenic dendritic cells

Monocytes can differentiate into macrophages (Mo-Macs) or dendritic cells (Mo-DCs). The cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) induces the differentiation of monocytes into Mo-Macs, while the combination of GM-CSF/interleukin (IL)-4 is widely used to generate Mo-DCs for clinical applications and to study human DC biology. Here, we report that pharmacological inhibition of the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) in the presence of GM-CSF and the absence of IL-4 induces monocyte differentiation into Mo-DCs. Remarkably, we find that simultaneous inhibition of PPARγ and the nutrient sensor mammalian target of rapamycin complex 1 (mTORC1) induces the differentiation of Mo-DCs with stronger phenotypic stability, superior immunogenicity, and a transcriptional profile characterized by a strong type I interferon (IFN) signature, a lower expression of a large set of tolerogenic genes, and the differential expression of several transcription factors compared with GM-CSF/IL-4 Mo-DCs. Our findings uncover a pathway that tailors Mo-DC differentiation with potential implications in the fields of DC vaccination and cancer immunotherapy.

Harnessing the reverse cholesterol transport pathway to favor differentiation of monocyte-derived APCs and antitumor responses

Lipid and cholesterol metabolism play a crucial role in tumor cell behavior and in shaping the tumor microenvironment. In particular, enzymatic and non-enzymatic cholesterol metabolism, and derived metabolites control dendritic cell (DC) functions, ultimately impacting tumor antigen presentation within and outside the tumor mass, dampening tumor immunity and immunotherapeutic attempts. The mechanisms accounting for such events remain largely to be defined. Here we perturbed (oxy)sterol metabolism genetically and pharmacologically and analyzed the tumor lipidome landscape in relation to the tumor-infiltrating immune cells. We report that perturbing the lipidome of tumor microenvironment by the expression of sulfotransferase 2B1b crucial in cholesterol and oxysterol sulfate synthesis, favored intratumoral representation of monocyte-derived antigen-presenting cells, including monocyte-DCs. We also found that treating mice with a newly developed antagonist of the oxysterol receptors Liver X Receptors (LXRs), promoted intratumoral monocyte-DC differentiation, delayed tumor growth and synergized with anti-PD-1 immunotherapy and adoptive T cell therapy. Of note, looking at LXR/cholesterol gene signature in melanoma patients treated with anti-PD-1-based immunotherapy predicted diverse clinical outcomes. Indeed, patients whose tumors were poorly infiltrated by monocytes/macrophages expressing LXR target genes showed improved survival over the course of therapy. Thus, our data support a role for (oxy)sterol metabolism in shaping monocyte-to-DC differentiation, and in tumor antigen presentation critical for responsiveness to immunotherapy. The identification of a new LXR antagonist opens new treatment avenues for cancer patients.

The role of miR-128 in cancer development, prevention, drug resistance, and immunotherapy

A growing body of evidence has revealed that microRNA (miRNA) expression is dysregulated in cancer, and they can act as either oncogenes or suppressors under certain conditions. Furthermore, some studies have discovered that miRNAs play a role in cancer cell drug resistance by targeting drug-resistance-related genes or influencing genes involved in cell proliferation, cell cycle, and apoptosis. In this regard, the abnormal expression of miRNA-128 (miR-128) has been found in various human malignancies, and its verified target genes are essential in cancer-related processes, including apoptosis, cell propagation, and differentiation. This review will discuss the functions and processes of miR-128 in multiple cancer types. Furthermore, the possible involvement of miR-128 in cancer drug resistance and tumor immunotherapeutic will be addressed.

Inflammation in Urological Malignancies: The Silent Killer

Several studies have investigated the role of inflammation in promoting tumorigenesis and cancer progression. Neoplastic as well as surrounding stromal and inflammatory cells engage in well-orchestrated reciprocal interactions to establish an inflammatory tumor microenvironment. The tumor-associated inflammatory tissue is highly plastic, capable of continuously modifying its phenotypic and functional characteristics. Accumulating evidence suggests that chronic inflammation plays a critical role in the development of urological cancers. Here, we review the origins of inflammation in urothelial, prostatic, renal, testicular, and penile cancers, focusing on the mechanisms that drive tumor initiation, growth, progression, and metastasis. We also discuss how tumor-associated inflammatory tissue may be a diagnostic marker of clinically significant tumor progression risk and the target for future anti-cancer therapies.

Novel biomimetic mesoporous silica nanoparticle system possessing targetability and immune synergy facilitates effective solid tumor immuno-chemotherapy

New strategies that enhance both the targetability of chemotherapy drugs and the synergistic effects of chemotherapy and immunotherapy are urgently needed for efficacious solid tumor therapy. In this study, a novel biomimetic nanoparticle system possessing the properties of tumor targeting and immune synergy was designed to meet these requirements. Mesoporous silica nanoparticles loaded with the chemotherapeutic drug doxorubicin (DOX) were coated with cell membranes modified by glycosylphosphatidylinositol (GPI)-anchored anti-HER2 single chain variable fragment (scFv) and the GPI-anchored co-stimulatory molecule CD80 (to promote solid tumor-targeted chemotherapy and cooperated immunotherapy, respectively). The impact of the nanotherapeutic system on both tumor-targeted chemotherapy and cellular immune response was investigated through in vitro and in vivo experiments. The results show that the novel biomimetic therapeutic system effectively promoted antitumor efficiency in vitro and in vivo. In addition, this therapeutic system further enhanced antitumor capacity by increasing CD8⁺ T cell activation and cytokine production and reducing myeloid-derived suppressor cell (MDSC) levels in tumors.

Role of NKT cells in cancer immunotherapy-from bench to bed

Natural killer T (NKT) cells are a specific T cell subset known to express the αβ-T cell receptor (TCR) for antigens identification and express typical NK cell specifications, such as surface expression of CD56 and CD16 markers as well as production of granzyme. Human NKT cells are divided into two subgroups based on their cytokine receptor and TCR repertoire. Both of them are CD1-restricted and recognize lipid antigens presented by CD1d molecules. Studies have demonstrated that these cells are essential in defense against malignancies. These cells secret proinflammatory and regulatory cytokines that stimulate or suppress immune system responses. In several murine tumor models, activation of type I NKT cells induces tumor rejection and inhibits metastasis's spread. However, type II NKT cells are associated with an inhibitory and regulatory function during tumor immune responses. Variant NKT cells may suppress tumor immunity via different mechanisms that require cross-talk with other immune-regulatory cells. NKT-like cells display high tumor-killing abilities against many tumor cells. In the recent decade, different studies have been performed based on the application of NKT-based immunotherapy for cancer therapy. Moreover, manipulation of NKT cells through administering autologous dendritic cell (DC) loaded with α-galactosylceramide (α-GalCer) and direct α-GalCer injection has also been tested. In this review, we described different subtypes of NKT cells, their function in the anti-tumor immune responses, and the application of NKT cells in cancer immunotherapy from bench to bed.

Peroxisome-related genes in hepatocellular carcinoma correlated with tumor metabolism and overall survival

BACKGROUND AND AIM

A prominent hallmark of tumors is aberrant lipid metabolism, and various peroxisome-related genes (PRGs) are associated with aberrant tumoral metabolic signaling. However, the influence of PRGs on the prognosis of hepatocellular carcinoma (HCC) patients remains debatable. Thus, the current study was designed to evaluate the effect of PRGs on HCC and construct a prognostic model for predicting survival.

METHODS

We initially acquired HCC-related gene expression profiles from the Cancer Genome Atlas and International Cancer Genome Consortium databases. We then utilized Cox analysis and Lasso regression to identify suitable PRGs for the risk model. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted to clarify the functional roles of PRGs. Single-sample gene set enrichment analysis (ssGSEA) was conducted to confirm the relationship between PRGs and immunity.

RESULTS

Four PRGs were correlated with HCC patient survival: 2 risk genes (MPV17, and ABCD1) and 2 protective genes (ACSL1 and ACSL6). We derived risk scores based on PRGs to construct a predictive model that could accurately predict overall survival (OS) among HCC patients. Furthermore, GO and KEGG analyses revealed that these PRGs were potentially involved in lipid metabolism and ferroptosis in HCC. Moreover, ssGSEA results demonstrated that high PRG scores were associated with immune suppressor activation, which caused the suppression of immune effectors (CD8⁺ T-cells, B cells, and NK cells) and the attenuation of the immune-mediated antitumor effect.

CONCLUSION

PRGs act as key regulators in tumorigenesis and tumor progression by affecting lipid synthesis and utilization, which we used to predict the outcome of HCC patients. Moreover, PRGs have been shown to promote tumoral immune resistance by serving as a vital bridge between metabolism and immunity. Thus, a personalized treatment approach targeting PRGs would clinically benefit patients by blocking the interaction between tumor metabolism and immunity.

Biological and molecular studies on specific immune cells treated with checkpoint inhibitors for the thera-personal approach of breast cancer patients (ex-vivo study)

Immunotherapy becomes a promising line of treatment for breast cancer (BC) however, its success rate is still limited.

Methods

The study was designed to optimize the condition for producing an effective dendritic cell (DCs) based immunotherapy by using DCs and T lymphocytes together with tumor-infiltrating lymphocytes (TILs) and tumor-infiltrating DCs (TIDCs), treated with anti-PD1 and anti-CTLA4 monoclonal antibodies. This mixture of immune cells was co-cultured with autologous breast cancer cells (BCCs) isolated from 26 BC females.

Results

There was a significant upregulation of CD86 and CD83 on DCs (p = 0.001 and 0.017, respectively), similarly upregulation of CD8, CD4 and CD103 on T cells (p = 0.031, 0.027, and 0.011, respectively). While there was a significant downregulation of FOXP3 and combined CD25.CD8 expression on regulatory T cells (p = 0.014 for both). Increased CD8/Foxp3 ratio (p < 0.001) was also observed. CD133, CD34 and CD44 were downregulated on BCCs (p = 0.01, 0.021, and 0.015, respectively). There was a significant increase in interferon-γ (IFN-γ, p < 0.001), lactate dehydrogenase (LDH, p = 0.02), and a significant decrease in vascular endothelial growth factor (VEGF, p < 0.001) protein levels. Gene expression of FOXP3 and Programmed cell death ligand 1 (PDL-1) were downregulated in BCCs (p < 0.001, for both), similarly cytotoxic T lymphocyte antigen-4 (CTLA4, p = 0.02), Programmed cell death 1 (PD-1, p < 0.001) and FOXP3 (p < 0.001) were significantly downregulated in T cells.

Conclusion

Ex-vivo activation of immune cells (DCs, T cells, TIDCs, and TILs) with immune checkpoint inhibitors could produce a potent and effective BC immunotherapy. However, these data should be validated on an experimental animal model to be transferred to the clinical setting.

Role of exosomal non-coding RNAs from tumor cells and tumor-associated macrophages in the tumor microenvironment

Exosomes have a crucial role in intercellular communication and mediate interactions between tumor cells and tumor-associated macrophages (TAMs). Exosome-encapsulated non-coding RNAs (ncRNAs) are involved in various physiological processes. Tumor-derived exosomal ncRNAs induce M2 macrophage polarization through signaling pathway activation, signal transduction, and transcriptional and post-transcriptional regulation. Conversely, TAM-derived exosomal ncRNAs promote tumor proliferation, metastasis, angiogenesis, chemoresistance, and immunosuppression. MicroRNAs induce gene silencing by directly targeting mRNAs, whereas lncRNAs and circRNAs act as miRNA sponges to indirectly regulate protein expressions. The role of ncRNAs in tumor-host interactions is ubiquitous. Current research is increasingly focused on the tumor microenvironment. On the basis of the "cancer-immunity cycle" hypothesis, we discuss the effects of exosomal ncRNAs on immune cells to induce T cell exhaustion, overexpression of programmed cell death ligands, and create a tumor immunosuppressive microenvironment. Furthermore, we discuss potential applications and prospects of exosomal ncRNAs as clinical biomarkers and drug delivery systems.

Nanomaterial-Based Drug Delivery Systems: A New Weapon for Cancer Immunotherapy

Cancer immunotherapy, a major breakthrough in cancer treatment, has been successfully applied to treat a number of tumors. However, given the presence of factors in the tumor microenvironment (TME) that impede immunotherapy, only a small proportion of patients achieve a good clinical response. With the ability to increase permeability and cross biological barriers, nanomaterials have been successfully applied to deliver immunotherapeutic agents, thus realizing the anti-cancer therapeutic potential of therapeutic agents. This has driven a wave of research into systems for the delivery of immunotherapeutic agents, which has resulted in widespread interest in nanomaterial-based drug delivery systems. Nanomaterial-based drug delivery systems are able to overcome the challenges from TME and thus achieve good results in cancer immunotherapy. If it can make a breakthrough in improving biocompatibility and reducing cytotoxicity, it will be more widely used in clinical practice. Different types of nanomaterials may also have some subtle differences in enhancing cancer immunotherapy. Moreover, delivery systems made of nanomaterials loaded with drugs, such as cytotoxic drugs, cytokines, and adjuvants, could be used for cancer immunotherapy because they avoid the toxicity and side effects associated with these drugs, thereby enabling their reuse. Therefore, further insights into nanomaterial-based drug delivery systems will provide more effective treatment options for cancer patients.

Immunosuppression in tumor immune microenvironment and its optimization from CAR-T cell therapy

Chimeric antigen receptor (CAR)-T cell therapy represents a landmark advance in personalized cancer treatment. CAR-T strategy generally engineers T cells from a specific patient with a new antigen-specificity, which has achieved considerable success in hematological malignancies, but scarce benefits in solid tumors. Recent studies have demonstrated that tumor immune microenvironment (TIME) cast a profound impact on the immunotherapeutic response. The immunosuppressive landscape of TIME is a critical obstacle to the effector activity of CAR-T cells. Nevertheless, every cloud has a silver lining. The immunosuppressive components also shed new inspiration on reshaping a friendly TIME by targeting them with engineered CARs. Herein, we summarize recent advances in disincentives of TIME and discuss approaches and technologies to enhance CAR-T cell efficacy via addressing current hindrances. Simultaneously, we firmly believe that by parsing the immunosuppressive components of TIME, rationally manipulating the complex interactions of immunosuppressive components, and optimizing CAR-T cell therapy for each patient, the CAR-T cell immunotherapy responsiveness for solid malignancies will be substantially enhanced, and novel therapeutic targets will be revealed.

The role of lipid metabolism in tumor immune microenvironment and potential therapeutic strategies

Aberrant lipid metabolism is nonnegligible for tumor cells to adapt to the tumor microenvironment (TME). It plays a significant role in the amount and function of immune cells, including tumor-associated macrophages, T cells, dendritic cells and marrow-derived suppressor cells. It is well-known that the immune response in TME is suppressed and lipid metabolism is closely involved in this process. Immunotherapy, containing anti-PD1/PDL1 therapy and adoptive T cell therapy, is a crucial clinical cancer therapeutic strategy nowadays, but they display a low-sensibility in certain cancers. In this review, we mainly discussed the importance of lipid metabolism in the formation of immunosuppressive TME, and explored the effectiveness and sensitivity of immunotherapy treatment by regulating the lipid metabolism.

Role of B cells as antigen presenting cells

B cells have been long studied for their role and function in the humoral immune system. Apart from generating antibodies and an antibody-mediated memory response against pathogens, B cells are also capable of generating cell-mediated immunity. It has been demonstrated by several groups that B cells can activate antigen-specific CD4 and CD8 T cells, and can have regulatory and cytotoxic effects. The function of B cells as professional antigen presenting cells (APCs) to activate T cells has been largely understudied. This, however, requires attention as several recent reports have demonstrated the importance of B cells within the tumor microenvironment, and B cells are increasingly being evaluated as cellular therapies. Antigen presentation through B cells can be through antigen-specific (B cell receptor (BCR) dependent) or antigen non-specific (BCR independent) mechanisms and can be modulated by a variety of intrinsic and external factors. This review will discuss the pathways and mechanisms by which B cells present antigens, and how B cells differ from other professional APCs.

Purinergic receptors are a key bottleneck in tumor metabolic reprogramming: The prime suspect in cancer therapeutic resistance

ATP and other nucleoside phosphates have specific receptors named purinergic receptors. Purinergic receptors and ectonucleotidases regulate various signaling pathways that play a role in physiological and pathological processes. Extracellular ATP in the tumor microenvironment (TME) has a higher level than in normal tissues and plays a role in cancer cell growth, survival, angiogenesis, metastasis, and drug resistance. In this review, we investigated the role of purinergic receptors in the development of resistance to therapy through changes in tumor cell metabolism. When a cell transforms to neoplasia, its metabolic processes change. The metabolic reprogramming modified metabolic feature of the TME, that can cause impeding immune surveillance and promote cancer growth. The purinergic receptors contribute to therapy resistance by modifying cancer cells' glucose, lipid, and amino acid metabolism. Limiting the energy supply of cancer cells is one approach to overcoming resistance. Glycolysis inhibitors which reduce intracellular ATP levels may make cancer cells more susceptible to anti-cancer therapies. The loss of the P2X7R through glucose intolerance and decreased fatty acid metabolism reduces therapeutic resistance. Potential metabolic blockers that can be employed in combination with other therapies will aid in the discovery of new anti-cancer immunotherapy to overcome therapy resistance. Therefore, therapeutic interventions that are considered to inhibit cancer cell metabolism and purinergic receptors simultaneously can potentially reduce resistance to treatment.

CD147 mediates epidermal malignant transformation through the RSK2/AP-1 pathway

Background

Malignant transformation of the epidermis is an essential process in the pathogenesis of cutaneous squamous-cell carcinoma (cSCC). Although evidence has demonstrated that CD147 plays key roles in various tumors, the role of CD147 in epidermal malignant transformation in vivo remains unclear.

Methods

Epidermal CD147-overexpression or knockout (EpiCD147-OE or EpiCD147-KO) transgenic mouse models were generated for in vivo study. RNA-sequencing and q-PCR were performed to identify the differentially expressed genes. Immunohistochemistry and flow cytometry were performed to investigate the role of CD147 in regulating myeloid-derived suppressor cells (MDSCs). Immunoprecipitation, EMSA and ChIP assays were performed to investigate the mechanism of CD147 in cell transformation.

Results

We found that specific overexpression of CD147 in the epidermis (EpiCD147-OE) induces spontaneous tumor formation; moreover, a set of chemokines and cytokines including CXCL1, which play essential function in MDSC recruitment, were significantly upregulated in EpiCD147-OE transgenic mice. As expected, overexpression of CD147 in the epidermis remarkably facilitated tumorigenesis by increasing the rate of tumor initiation and the number and size of tumors in the DMBA/TPA mouse model. Interestingly, the expression of CXCL1 and the infiltration of MDSCs were dramatically increased in EpiCD147-OE transgenic mice. Our findings also showed that knockdown of CD147 attenuated EGF-induced malignant transformation as well as CXCL1 expression in HaCaT cells. Consistently, CD147 was found overexpressed in cutaneous squamous cell carcinoma (cSCC), and positively related with the expression of CD33, a myeloid-associated marker. We further identified RSK2, a serine/threonine kinase, as an interacting partner of CD147 at the binding site of CD147D207-230. The interaction of CD147 and RSK2 activated RSK2, thus enhancing AP-1 transcriptional activation. Furthermore, EMSAs and ChIP assays showed that AP-1 could associate with the CXCL1 promoter. Importantly, RSK2 inhibitor suppressed the tumor growth in DMBA/TPA mouse model by inhibiting the recruitment of MDSCs.

Conclusion

Our findings demonstrate that CD147 exerts a key function in epidermal malignant transformation in vivo by activating keratinocytes and recruiting MDSCs via the RSK2/AP-1 pathway.

Early T-cell precursor lymphoblastic leukemia accompanied by prominent blastic plasmacytoid dendritic cell proliferation mimicking blastic plasmacytoid dendritic cell neoplasm: an exceptional case report and literature review

PURPOSE

Plasmacytoid dendritic cells (pDCs) are commonly associated with myeloid malignancies. The association between lymphoblastic leukemia and pDCs has been little explored.

CASE PRESENTATION

Here, we report a novel case of early T-cell precursor lymphoblastic leukemia (ETP-ALL) accompanied by prominent proliferation of blastic pDCs mimicking BPDCN. The diagnosis was established based on a comprehensive analysis of morphology, immunophenotype and clinical implications. We also present a literature review and discussion on the differential expression of reactive and neoplastic pDCs, the functional role of pDCs in lymphoblastic leukemia, and the etiological association of normal pDCs and BPDCN.

CONCLUSIONS

The current case demonstrates for the first time that prominent pDC proliferation can be associated with lymphoid neoplasms and can exhibit blastic morphology and immunophenotype. The underlying mechanism of the coexistence of these two blastic populations remains unknown. Further genetic profiling may be required to denote the progressive development of tumor stem cells to the lymphoid, myeloid or dendritic cell lineage. Moreover, the prognostic value of pDCs in hematological neoplasms needs further investigation.

Stem Cells in the Tumor Immune Microenvironment -Part of the Cure or Part of the Disease? Ontogeny and Dichotomy of Stem and Immune Cells has Led to better Understanding

Stem cells are at the basis of tissue homeostasis, hematopoiesis and various regenerative processes. Epigenetic changes in their somatically imprinted genes, prolonged exposure to mutagens/carcinogens or alteration of their niche can lead to the development of an enabling environment for tumor growth and progression. The involvement of stem cells in both health and disease becomes even more compelling with ontogeny as embryonic and extraembryonic stem cells which persist into adulthood in well established and specific niche may have distinct implications in tumorigenesis. Immune surveillance plays an important role in this interplay since the response of immune cells toward the oncogenic process can range from reactivity to placidity and even complicity, being orchestrated by intercellular molecular dialogues with the other key players of the tumor microenvironment. With the current understanding that every developing and adult tissue contains inherent stem and progenitor cells, in this manuscript we review the most relevant interactions carried out between the stem cells, tumor cells and immune cells in a bottom-up incursion through the tumor microenvironment beginning from the perivascular niche and going through the tumoral parenchyma and the related stroma. With the exploitation of various factors that influence the behavior of immune effectors toward stem cells and other resting cells in their niche, new therapeutic strategies to tackle the polarization of immune effectors toward a more immunogenic phenotype may arise.

Advances in MUC1-Mediated Breast Cancer Immunotherapy

Breast cancer (BRCA) is the leading cause of death from malignant tumors among women. Fortunately, however, immunotherapy has recently become a prospective BRCA treatment with encouraging achievements and mild safety profiles. Since the overexpression and aberrant glycosylation of MUC1 (human mucin) are closely associated with BRCA, it has become an ideal target for BRCA immunotherapies. In this review, the structure and function of MUC1 are briefly introduced, and the main research achievements in different kinds of MUC1-mediated BRCA immunotherapy are highlighted, from the laboratory to the clinic. Afterward, the future directions of MUC1-mediated BRCA immunotherapy are predicted, addressing, for example, urgent issues in regard to how efficient immunotherapeutic strategies can be generated.

Myeloid derived suppressor cells and innate immune system interaction in tumor microenvironment

The tumor microenvironment is a complex domain that not only contains tumor cells but also a plethora of other host immune cells. By nature, the tumor microenvironment is a highly immunosuppressive milieu providing growing conditions for tumor cells. A major immune cell population that contributes most in the development of this immunosuppressive microenvironment is the MDSC, a heterogenous population of immature cells. Although found in small numbers only in the bone marrow of healthy individuals, they readily migrate to the lymph nodes and tumor site during cancer pathogenesis. MDSC mediated disruption of antitumor T cell activity is a major cause of the immunosuppression at the tumor site, but recent findings have shown that MDSC mediated dysfunction of other major immune cells might also play an important role. In this article we will review how crosstalk with MDSC alters the activity of both conventional and unconventional immune cells that inhibits the antitumor immunity and promotes cancer progression.

The Role of Lipid Metabolism in Gastric Cancer

Gastric cancer has been one of the most common cancers worldwide with extensive metastasis and high mortality. Chemotherapy has been found as a main treatment for metastatic gastric cancer, whereas drug resistance limits the effectiveness of chemotherapy and leads to treatment failure. Chemotherapy resistance in gastric cancer has a complex and multifactorial mechanism, among which lipid metabolism plays a vital role. Increased synthesis of new lipids or uptake of exogenous lipids can facilitate the rapid growth of cancer cells and tumor formation. Lipids form the structural basis of biofilms while serving as signal molecules and energy sources. It is noteworthy that lipid metabolism is capable of inducing drug resistance in gastric cancer cells by reshaping the tumor micro-environment. In this study, new mechanisms of lipid metabolism in gastric cancer and the metabolic pathways correlated with chemotherapy resistance are reviewed. In particular, we discuss the effects of lipid metabolism on autophagy, biomarkers treatment and drug resistance in gastric cancer from the perspective of lipid metabolism. In brief, new insights can be gained into the development of promising therapies through an in-depth investigation of the mechanism of lipid metabolism reprogramming and resensitization to chemotherapy in gastric cancer cells, and scientific treatment can be provided by applying lipid-key enzyme inhibitors as cancer chemical sensitizers in clinical settings.

MDSCs and T cells in solid tumors and non-Hodgkin lymphomas: an immunosuppressive speech

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous subset of cells expanded during multiple pathological settings, including cancers. In tumors, MDSCs are dominant drivers of T-cell immunosuppression. To accomplish their job, they exploit multiple mechanisms ultimately leading to the paralysis of anti-tumor immunity. Among the variety of MDSC-ways of working within the tumor microenvironment, the generation of reactive species and the metabolic reprogramming have emerged as pivotal determinants of their immunosuppressive power. In this review we will overview integral mechanisms of MDSC-mediated immunosuppression in solid tumors, with a particular focus on Non-Hodgkin lymphoma.

Immunosuppressive cells in cancer: mechanisms and potential therapeutic targets

Immunotherapies like the adoptive transfer of gene-engineered T cells and immune checkpoint inhibitors are novel therapeutic modalities for advanced cancers. However, some patients are refractory or resistant to these therapies, and the mechanisms underlying tumor immune resistance have not been fully elucidated. Immunosuppressive cells such as myeloid-derived suppressive cells, tumor-associated macrophages, tumor-associated neutrophils, regulatory T cells (Tregs), and tumor-associated dendritic cells are critical factors correlated with immune resistance. In addition, cytokines and factors secreted by tumor cells or these immunosuppressive cells also mediate the tumor progression and immune escape of cancers. Thus, targeting these immunosuppressive cells and the related signals is the promising therapy to improve the efficacy of immunotherapies and reverse the immune resistance. However, even with certain success in preclinical studies or in some specific types of cancer, large perspectives are unknown for these immunosuppressive cells, and the related therapies have undesirable outcomes for clinical patients. In this review, we comprehensively summarized the phenotype, function, and potential therapeutic targets of these immunosuppressive cells in the tumor microenvironment.

Beyond Immunosuppression: The Multifaceted Functions of Tumor-Promoting Myeloid Cells in Breast Cancers

Breast cancers are commonly associated with an immunosuppressive microenvironment responsible for tumor escape from anti-cancer immunity. Cells of the myeloid lineage account for a major part of this tumor-promoting landscape. These myeloid cells are composed of heterogeneous subsets at different stages of differentiation and have traditionally been described by their cardinal ability to suppress innate and adaptive anticancer immunity. However, evidence has accumulated that, beyond their immunosuppressive properties, breast cancer-induced myeloid cells are also equipped with a broad array of “non-immunological” tumor-promoting functions. They therefore represent major impediments for anticancer therapies, particularly for immune-based interventions. We herein analyze and discuss current literature related to the versatile properties of the different myeloid cell subsets engaged in breast cancer development. We critically assess persisting difficulties and challenges in unequivocally discriminate dedicated subsets, which has so far prevented both the selective targeting of these immunosuppressive cells and their use as potential biomarkers. In this context, we propose the concept of IMCGL, “pro-tumoral immunosuppressive myeloid cells of the granulocytic lineage”, to more accurately reflect the contentious nature and origin of granulocytic cells in the breast tumor microenvironment. Future research prospects related to the role of this myeloid landscape in breast cancer are further considered.

Liver Immunology, Immunotherapy, and Liver Cancers: Time for a Rethink?

The complex immune system of the liver has a major role in tumor surveillance, but also partly explains why current immune therapies are poorly effective against liver cancers. Known primarily for its tolerogenic capacity, the hepatic immune repertoire also comprises diverse populations of armored immune cells with tumor surveillant roles. In healthy people, these work together to successfully identify malignant cells and prevent their proliferation, thus halting tumor formation. When frontline hepatic immune surveillance systems fail, compromised hepatic immunity, driven by obesity, infection, or other pathological factors, allows primary or secondary liver cancers to develop. Tumor growth promotes the normal tolerogenic immunological milieu of the liver, perhaps explaining why current immunotherapies fail to work. This review explores the complex local liver immune system with the hope of identifying potential therapeutic targets needed to best overcome immunological barriers in the liver to create an environment no longer hostile to immunotherapy for the treatment of liver cancer.

Differential responses to immune checkpoint inhibitor dictated by pre-existing differential immune profiles in squamous cell carcinomas caused by same initial oncogenic drivers

BACKGROUND

While immune checkpoint inhibitors (ICI) were approved for head and neck squamous cell carcinomas (HNSCCs), the response rate remains relatively low. Mechanisms underlying ICI unresponsiveness versus sensitivity are not fully understood.

METHOD

To better delineate differential responses to ICI treatment, we employed mouse SCC models, termed KPPA tumors that were caused by deleting p53 and hyperactivating PIK3CA, two most frequently mutated genes in human HNSCCs. We transplanted two KPPA tumor lines (TAb2 versus TCh3) into C57BL/6 recipients and examined the immune tumor microenvironment using flow cytometry. Furthermore, we employed single-cell RNA sequencing to identify the difference in tumor infiltrating lymphocytes (TILs).

RESULTS

We found that different KPPA tumors exhibited heterogeneous immune profiles pre-existing treatment that dictated their sensitivity or unresponsiveness to anti-PD-L1. Unresponsive TAb2 tumors were highly enriched with functional tumor-associated macrophages (TAMs), especially M2-TAMs. In contrast, sensitive TCh3 tumors contained more CD8 TILs with better effector functions. TAb2 tumor cells drastically expanded F4/80⁺ TAMs from bone marrow precursors, requiring CSF1 and VEGF. Consistently, a higher combined expression of VEGF-C and CSF1 predicts worse survival in PIK3CA^Amp/TP53^Mutated HNSCC patients. Unresponsive TAb2 tumors upregulated distinct signaling pathways that correlate with aggressive tumor phenotypes. While anti-PD-L1 did not affect the TME of TAb2 tumors, it significantly increased the number of CD8 TILs in TCh3 tumors.

CONCLUSIONS

We uncovered tumor-intrinsic differences that may underlie the differential responses to ICI by establishing and employing two SCC tumor lines, TAb2 vs. TCh3, both of which harbor TP53 deletion and PIK3CA hyperactivation. Our study indicates the limitation of stratifying cancers according to their genetic alterations and suggests that evaluating HNSCC tumor-intrinsic cues along with immune profiles in the TME may help better predict ICI responses. Our experimental models may provide a platform for pinpointing tumor-intrinsic differences underlying an immunosuppressive TME in HNSCCs and for testing combined immunotherapies targeting either tumor-specific or TAM-specific players to improve ICI efficacy.

Exosomes reveal the dual nature of radiotherapy in tumor immunology

Radioresistance is the potential cause of cancer metastasis and recurrence. Radiation‐induced changes in exosomes can partially explain the undesirable prognosis of radiotherapy (RT). Exosomes, newly discovered ways of cell communication, carry the characteristics of their origin, resulting in their diversity. Various exosomes in the tumor microenvironment exert different function in immune response. In this review, the dual effect of RT on the immune system was described, and the effect of radiotherapy on tumors via exosomes was explored. The molecules in exosomes after RT were described to play immunosuppressive and immunocompetent roles: immune‐related receptors and cell signaling molecules involved in both adaptive and innate immune system were present. CD69, TIGIT, TIM‐3, LAG‐3 and the tumor necrosis factor (TNF) family that signal to T cells were shown to be regulated by exosomes after irradiation. The change in innate immunity‐derived like receptors, Leukocyte Immunoglobin‐Like Receptors (LILR) was described, as well as B7‐H3, V‐domain containing Ig suppressor of T cell activation (VISTA), and CD155 on tumor cells. These changed molecules inhibit and activate the immune system through different mechanisms. By analyzing the relationship between exosome‐derived molecules and immunity, this review shows that radiotherapy can induce immunosuppression and immune clearance through exosomes, thereby treating tumors and improving patient prognosis.

Role of Hypoxia in the Interferon Response

In solid tumors, as the tumor grows and the disease progresses, hypoxic regions are often generated, but in contrast to most normal cells which cannot survive under these conditions, tumour cells adapt to hypoxia by HIF-driven mechanisms. Hypoxia can further promote cancer development by generating an immunosuppressive environment within the tumour mass, which allows tumour cells to escape the immune system recognition. This is achieved by recruiting immunosuppressive cells and by upregulating molecules which block immune cell activation. Hypoxia can also confer resistance to antitumor therapies by inducing the expression of membrane proteins that increase drug efflux or by inhibiting the apoptosis of treated cells. In addition, tumor cells require an active interferon (IFN) signalling pathway for the success of many anticancer therapies, such as radiotherapy or chemotherapy. Therefore, hypoxic effects on this pathway needs to be addressed for a successful treatment.

Aberrant lipid metabolism reprogramming and immune microenvironment for gastric cancer: a literature review

Objective

We summarize the aberrant lipid metabolism disorders associated with enzyme activity and expression changes and related immune microenvironment for gastric cancer.

Background

Gastric cancer is a malignant tumor of the primary digestive system with high incidence, poor prognosis characterized by extensive metastasis and poor effect with radiotherapy and chemotherapy. One of the most important metabolic characteristics of cancer cells is lipid metabolism reprogramming to adapt to the tumor micro-environment.

Methods

The focus of research in recent years has also been on lipid metabolism disorders, particularly aberrant metabolism of fatty acids (FAs) in gastric cancer cells, as well as an upregulation of the expression and activity of key enzymes in lipid metabolism. These changes remind us of the occurrence and development of gastric cancer. These metabolic changes are not unique to cancer cells. Changes in metabolic procedures also determine the function and viability of immune cells. In the immune microenvironment of gastric cancer, the metabolic competition and interaction between cancer cells and immune cells are not very clear, while a deeper understanding of the topic is critical to targeting the differential metabolic requirements of them that comprise an immune response to cancer offers an opportunity to selectively regulate immune cell function.

Conclusions

Recent research suggests that targeting metabolism is an emerging and potentially promising treatment strategy for gastric cancer patients. We need to explore it further.

Identification and validation of a novel signature for prediction the prognosis and immunotherapy benefit in bladder cancer

BACKGROUND

Bladder cancer (BC) is a common urinary tract system tumor with high recurrence rate and different populations show distinct response to immunotherapy. Novel biomarkers that can accurately predict prognosis and therapeutic responses are urgently needed. Here, we aim to identify a novel prognostic and therapeutic responses immune-related gene signature of BC through a comprehensive bioinformatics analysis.

METHODS

The robust rank aggregation was conducted to integrate differently expressed genes (DEGs) in datasets of the Cancer Genome Atlas (TCGA) and the gene expression omnibus (GEO). Lasso and Cox regression analyses were performed to formulate a novel mRNA signature that could predict prognosis of BC patients. Subsequently, the prognostic value and predictive value of the signature was validated with two independent cohorts GSE13507 and IMvigor210. Finally, quantitative Real-time PCR (qRT-PCR) analysis was conducted to determine the expression of mRNAs in BC cell lines (UM-UC-3, EJ-1, SW780 and T24).

RESULTS

We built a signature comprised the eight mRNAs: CNKSR1, COPZ2, CXorf57, FASN, PCOLCE2, RGS1, SPINT1 and TPST1. Our prognostic signature could be used to stratify BC population into two risk groups with distinct immune profile and responsiveness to immunotherapy. The results of qRT-PCR demonstrated that the eight mRNAs exhibited different expression levels in BC cell lines.

CONCLUSION

Our study constructed a convenient and reliable 8-mRNA gene signature, which might provide prognostic prediction and aid treatment decision making of BC patients in clinical practice.

Screening and analysis of RNAs associated with activated memory CD4 and CD8 T cells in liver cancer

Background

Liver cancer is one of the most common malignant tumors in the world. T cell-mediated antitumor immune response is the basis of liver cancer immunotherapy.

Objective

To screen and analyze the RNAs associated with activated memory CD4 T cells and CD8 T cells in liver cancer.

Methods

ESTIMATE was used to calculate the stromal and immune scores of tumor samples, which were downloaded from The Cancer Genome Atlas (TCGA). The differentially expressed genes (DEGs) in high and low stromal and immune scores were screened, followed by functional enrichment of overlapped DEGs. We then conducted a survival analysis to identify immune-related prognostic indicators and constructed protein-protein interaction (PPI) networks and ceRNA networks. Finally, chemical small-molecule–target interaction pairs associated with liver cancer were screened.

Results

A total of 55,955 stromal-related DEGs and 1811 immune-related DEGs were obtained. The 1238 overlapped DEGs were enriched in 1457 biological process terms and 74 KEGG pathways. In addition, a total of 120 activated memory CD4 T cell-related genes and 309 CD8 T cell-related genes were identified. The survival analysis revealed that upregulated expression of T cell-related genes including EOMES, CST7, and CD5L indicated the favorable prognosis of liver cancer. EOMES was regulated by has-miR-23b-3p and has-miR-23b-3p was regulated by lncRNA AC104820.2 in the ceRNA network of activated memory CD4 T cell-related genes. In addition, EOMES was regulated by has-miR-23a-3p and has-miR-23a-3p was regulated by lncRNA AC000476.1 in the ceRNA network of CD8 T cells.

Conclusion

T cell-related RNAs EOMES, CST7, CD5L, has-miR-23b-3p, and has-miR-23a-3p may be associated with the prognosis of liver cancer. And the molecular characteristics of these T cell-related genes were plotted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02461-6.

A total of 309 CD8 T cell-related genes and 120 activated memory CD4 T cell-related genes were screened in liver cancer tumor samples.

Forty-four chemical small-molecule–target interaction pairs associated with activated memory CD4 T cells and 276 pairs associated with CD8 T cells were screened.

Upregulated expression of T cell-related genes including EOMES, CST7, and CD5L indicated the favorable prognosis of liver cancer.