Tumor Microenvironment: A Metabolic Player that Shapes the Immune Response

Modulation of diverse oncogenic signaling pathways by oroxylin A: An important strategy for both cancer prevention and treatment

BACKGROUND

Regardless of major advances in diagnosis, prevention and treatment strategies, cancer is still a foreboding cause due to factors like chemoresistance, radioresistance, adverse side effects and cancer recurrence. Therefore, continuous development of unconventional approaches is a prerequisite to overcome foregoing glitches. Natural products have found their way into treatment of serious health conditions, including cancer since ancient times. The compound oroxylin A (OA) is one among those with enormous potential against different malignancies. It is a flavonoid obtained from the several plants such as Oroxylum indicum, Scutellaria baicalensis and S. lateriflora, Anchietea pyrifolia, and Aster himalaicus.

PURPOSE

The main purpose of this study is to comprehensively elucidate the anticancerous effects of OA against various malignancies and unravel their chemosensitization and radiosensitization potential. Pharmacokinetic and pharmacodynamic studies of OA have also been investigated.

METHOD

The literature on antineoplastic effects of OA was searched in PubMed and Scopus, including in vitro and in vivo studies and is summarized based on a systematic review protocol prepared according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The term "oroxylin A" was used in combination with "cancer" and all the title, abstracts and keywords appeared were considered.

RESULTS

In Scopus, a total of 157 articles appeared out of which 103 articles that did not meet the eligibility criteria were eliminated and 54 were critically evaluated. In PubMed, from the 85 results obtained, 26 articles were eliminated and 59 were included in the preparation of this review. Mounting number of studies have illustrated the anticancer effects of OA, and its mechanism of action.

CONCLUSION

OA is a promising natural flavonoid possessing wide range of pleiotropic properties and is a potential anticancer agent. It has a great potential in the treatment of multiple cancers including brain, breast, cervical, colon, esophageal, gall bladder, gastric, hematological, liver, lung, oral, ovarian, pancreatic and skin. However, lack of pharmacokinetic studies, toxicity assessments, and dose standardization studies and adverse effects limit the optimization of this compound as a therapeutic agent.

Synergizing liver systemic treatments with interventional oncology: friend or foe?

Interventional radiology techniques provide excellent local tumor control for small tumors in various organs, but several limitations can hamper the oncological outcomes such as the tumor size or the number of lesions. Technical improvements, optimal patient selection and combination with systemic therapies, including immune checkpoint inhibitors, have been successfully developed to overcome these barriers.In this setting, chemotherapy and targeted therapies aim to diminish the tumor burden in addition to local treatments, while immunotherapies may have a synergistic effect in terms of mechanism of action on the tumor cell as well as the immune environment, with multiple treatment combinations being available. Finally, interventional Rrdiology treatments often increase tumor antigen exposure to the immune system, and thus stimulate a specific antitumor immune response that can act beyond the treated site. Notwithstanding their many benefits, combination treatment may also result in complications, the most feared may be auto-immune-related adverse events.In early studies, several combined therapies have shown promising levels of safety and efficacy, particularly in hepatocellular carcinoma.This review provides a comprehensive and up-to-date overview of results of combined therapies for primary and secondary liver malignancies. Recent advances and future perspectives will be discussed.

A prognostic signature of pyroptosis-related lncRNAs verified in gastric cancer samples to predict the immunotherapy and chemotherapy drug sensitivity

Background: Pyroptosis is a recently identified mode of programmed inflammatory cell death that has remarkable implications for cancer development. lncRNAs can be involved in cellular regulation through various pathways and play a critical role in gastric cancer (GC). However, pyroptosis -related lncRNAs (PRlncRNAs) have been rarely studied in GC.

Methods: Pyroptosis-related gene were abstracted from the literature and GSEA Molecular Signatures data resource. PRlncRNAs were obtained using co-expression analysis. LASSO Cox regression assessment was employed to build a risk model. Kaplan-Meier (KM), univariate along with multivariate Cox regression analysis were adopted to verify the predictive efficiency of the risk model in terms of prognosis. qRT-PCR was adopted to validate the expression of PRlncRNAs in GC tissues. In addition, immune cell infiltration assessment and ESTIMATE score evaluation were adopted for assessing the relationship of the risk model with the tumor immune microenvironment (TME). Finally, immune checkpoint gene association analysis and chemotherapy drug sensitivity analysis were implemented to assess the worthiness of our risk model in immunotherapy and chemotherapy of GC.

Results: We identified 3 key PRlncRNAs (PVT1, CYMP-AS1 and AC017076.1) and testified the difference of their expression levels in GC tumor tissues and neighboring non-malignant tissues (p < 0.05). PRlncRNAs risk model was able to successfully estimate the prognosis of GC patients, and lower rate of survival was seen in the high-GC risk group relative to the low-GC risk group (p < 0.001). Other digestive system tumors such as pancreatic cancer further validated our risk model. There was a dramatic difference in TMB level between high-GC and low-GC risk groups (p < 0.001). Immune cell infiltration analysis and ESTIMATE score evaluation demonstrated that the risk model can be adopted as an indicator of TME status. Besides, the expressions of immunodetection site genes in different risk groups were remarkably different (CTLA-4 (r = −0.14, p = 0.010), VISTA (r = 0.15, p = 0.005), and B7-H3 (r = 0.14, p = 0.009)). PRlncRNAs risk model was able to effectively establish a connection with the sensitivity of chemotherapeutic agents.

Conclusion: The 3 PRlncRNAs identified in this study could be utilized to predict disease outcome in GC patients. It may also be a potential therapeutic target in GC therapy, including immunotherapy and chemotherapy.

Nanoformulation improves antitumor efficacy of MAOI immune checkpoint blockade therapy without causing aggression-related side effects

MAOIs, a well-established class of antidepressant that operate through the inhibition of monoamine oxidase to increase available serotonin, have recently been identified as a surprisingly effective candidate for the circumvention of tumor-induced immune suppression due to their abilities to enhance antitumor T cell activity through autocrine serotonin signaling and depolarize alternatively activated tumor-associated macrophages through a reduction in reactive oxygen species production. However, this impressive class of antidepressants-turned-cancer-drugs can induce aggressive behavioral side effects when administered in immunotherapeutic doses. In this study, we investigated the possibility of avoiding these neurological side effects while simultaneously improving antitumor activity by establishing crosslinked multilamellar liposomal vesicles (cMLVs) containing the MAOI phenelzine (PLZ). Our results showed that cMLV-PLZ treatment increases antitumor efficacy in a B16-OVA mouse melanoma model compared to treatment with free phenelzine. We also found that nanoformulation resulted in the complete elimination of MAOI-related aggression. These findings suggest a promising direction for the future of MAOIs repurposed for cancer immunotherapies.

A novel prognostic and therapeutic target biomarker based on necroptosis-related gene signature and immune microenvironment infiltration in gastric cancer

Background: Gastric cancer is a major global public health burden worldwide. Although treatment strategies are continuously improving, the overall prognosis remains poor. Necroptosis is a newly discovered form of cell death associated with anti-tumor immunity.

Methods: Gastric cancer (GC) data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) were downloaded. Bioinformatics analysis was performed to construct a necroptosis-related risk model and to establish cancer subtypes. Potential associations of the tumor immune microenvironment and immunotherapy response with necroptosis-related prognostic risk score (NRG risk score) were comprehensively explored. 16 GC and paired normal tissues were collected and RT-PCR was performed to examine expression of NRG related genes.

Results: GC samples were stratified into three subtypes according to prognostic necroptosis gene expression. A necroptosis risk model based on 12 genes (NPC1L1, GAL, RNASE1, PCDH7, NOX4, GJA4, SLC39A4, BASP1, BLVRA, NCF1, PNOC, and CCR5) was constructed and validated. The model was significantly associated with the OS and PFS of GC patients and the tumor immune microenvironment including immune cell infiltration, microsatellite instability (MSI) status, tumor mutational burden (TMB) score, immune checkpoint, and human leukocyte antigen (HLA) gene expression. A prognostic nomogram based on the NRG_score was additionally constructed. A low NRG risk score was correlated with high tumor immunogenicity and might benefit from immunotherapy.

Conclusion: We have identified a useful prognostic model based on necroptosis-related genes in GC and comprehensively the relationship between necroptosis and tumor immunity. Predicting value to immunotherapy response is promising, and further research to validate the model in clinical practice is needed.

Adipokines in Non-Alcoholic Fatty Liver Disease: Are We on the Road toward New Biomarkers and Therapeutic Targets?

Simple Summary

Non-alcoholic fatty liver disease (NAFLD) is an unmet medical need due to its increasingly high incidence, severe clinical consequences, and the absence of feasible diagnostic tools and effective drugs. This review summarizes the preclinical and clinical data on adipokines, cytokine-like hormones secreted by adipose tissue, and NAFLD. The aim is to establish the potential of adipokines as diagnostic and prognostic biomarkers, as well as their potential as therapeutic targets for NAFLD. The limitations of current research are also discussed, and future perspectives are outlined.

Abstract

Non-alcoholic fatty liver disease (NAFLD) has become the major cause of chronic hepatic illness and the leading indication for liver transplantation in the future decades. NAFLD is also commonly associated with other high-incident non-communicable diseases, such as cardiovascular complications, type 2 diabetes, and chronic kidney disease. Aggravating the socio-economic impact of this complex pathology, routinely feasible diagnostic methodologies and effective drugs for NAFLD management are unavailable. The pathophysiology of NAFLD, recently defined as metabolic associated fatty liver disease (MAFLD), is correlated with abnormal adipose tissue–liver axis communication because obesity-associated white adipose tissue (WAT) inflammation and metabolic dysfunction prompt hepatic insulin resistance (IR), lipid accumulation (steatosis), non-alcoholic steatohepatitis (NASH), and fibrosis. Accumulating evidence links adipokines, cytokine-like hormones secreted by adipose tissue that have immunometabolic activity, with NAFLD pathogenesis and progression; however, much uncertainty still exists. Here, the current knowledge on the roles of leptin, adiponectin, ghrelin, resistin, retinol-binding protein 4 (RBP4), visfatin, chemerin, and adipocyte fatty-acid-binding protein (AFABP) in NAFLD, taken from preclinical to clinical studies, is overviewed. The effect of therapeutic interventions on adipokines’ circulating levels are also covered. Finally, future directions to address the potential of adipokines as therapeutic targets and disease biomarkers for NAFLD are discussed.

The metabolic addiction of cancer stem cells

Cancer stem cells (CSC) are the minor population of cancer originating cells that have the capacity of self-renewal, differentiation, and tumorigenicity (when transplanted into an immunocompromised animal). These low-copy number cell populations are believed to be resistant to conventional chemo and radiotherapy. It was reported that metabolic adaptation of these elusive cell populations is to a large extent responsible for their survival and distant metastasis. Warburg effect is a hallmark of most cancer in which the cancer cells prefer to metabolize glucose anaerobically, even under normoxic conditions. Warburg's aerobic glycolysis produces ATP efficiently promoting cell proliferation by reprogramming metabolism to increase glucose uptake and stimulating lactate production. This metabolic adaptation also seems to contribute to chemoresistance and immune evasion, a prerequisite for cancer cell survival and proliferation. Though we know a lot about metabolic fine-tuning in cancer, what is still in shadow is the identity of upstream regulators that orchestrates this process. Epigenetic modification of key metabolic enzymes seems to play a decisive role in this. By altering the metabolic flux, cancer cells polarize the biochemical reactions to selectively generate "onco-metabolites" that provide an added advantage for cell proliferation and survival. In this review, we explored the metabolic-epigenetic circuity in relation to cancer growth and proliferation and establish the fact how cancer cells may be addicted to specific metabolic pathways to meet their needs. Interestingly, even the immune system is re-calibrated to adapt to this altered scenario. Knowing the details is crucial for selective targeting of cancer stem cells by choking the rate-limiting stems and crucial branch points, preventing the formation of onco-metabolites.

Crosstalk among m6A RNA methylation, hypoxia and metabolic reprogramming in TME: from immunosuppressive microenvironment to clinical application

The tumor microenvironment (TME), which is regulated by intrinsic oncogenic mechanisms and epigenetic modifications, has become a research hotspot in recent years. Characteristic features of TME include hypoxia, metabolic dysregulation, and immunosuppression. One of the most common RNA modifications, N6-methyladenosine (m⁶A) methylation, is widely involved in the regulation of physiological and pathological processes, including tumor development. Compelling evidence indicates that m⁶A methylation regulates transcription and protein expression through shearing, export, translation, and processing, thereby participating in the dynamic evolution of TME. Specifically, m⁶A methylation-mediated adaptation to hypoxia, metabolic dysregulation, and phenotypic shift of immune cells synergistically promote the formation of an immunosuppressive TME that supports tumor proliferation and metastasis. In this review, we have focused on the involvement of m⁶A methylation in the dynamic evolution of tumor-adaptive TME and described the detailed mechanisms linking m⁶A methylation to change in tumor cell biological functions. In view of the collective data, we advocate treating TME as a complete ecosystem in which components crosstalk with each other to synergistically achieve tumor adaptive changes. Finally, we describe the potential utility of m⁶A methylation-targeted therapies and tumor immunotherapy in clinical applications and the challenges faced, with the aim of advancing m⁶A methylation research.

Nanotechnology-Based siRNA Delivery Systems to Overcome Tumor Immune Evasion in Cancer Immunotherapy

Immune evasion is a common reason causing the failure of anticancer immune therapy. Small interfering RNA (siRNA), which can activate the innate and adaptive immune system responses by silencing immune-relevant genes, have been demonstrated to be a powerful tool for preventing or reversing immune evasion. However, siRNAs show poor stability in biological fluids and cannot efficiently cross cell membranes. Nanotechnology has shown great potential for intracellular siRNA delivery in recent years. Nano-immunotherapy can efficiently penetrate the tumor microenvironment (TME) and deliver multiple immunomodulatory agents simultaneously, which appears to be a promising method for combination therapy. Therefore, it provides a new perspective for siRNA delivery in immunomodulation and cancer immunotherapy. The current advances and challenges in nanotechnology-based siRNA delivery strategies for overcoming immune evasion will be discussed in this review. In addition, we also offer insights into therapeutic options, which may expand its applications in clinical cancer treatment.

Emerging Management Approach for the Adverse Events of Immunotherapy of Cancer

Immunotherapy, which stimulates the body’s immune system, has received a considerable amount of press in recent years because of its powerful benefits. Cancer immunotherapy has shown long-term results in patients with advanced disease that are not seen with traditional chemotherapy. Immune checkpoint inhibitors, cytokines like interleukin 2 (IL-2) and interferon-alpha (IFN), and the cancer vaccine sipuleucel-T have all been licensed and approved by the FDA for the treatment of various cancers. These immunotherapy treatments boost anticancer responses by stimulating the immune system. As a result, they have the potential to cause serious, even fatal, inflammatory and immune-related side effects in one or more organs. Immune checkpoint inhibitors (ICPIs) and chimeric antigen receptor (CAR) T-cell therapy are two immunotherapy treatments that are increasingly being used to treat cancer. Following their widespread usage in the clinic, a wave of immune-related adverse events (irAEs) impacting virtually every system has raised concerns about their unpredictability and randomness. Despite the fact that the majority of adverse effects are minimal and should be addressed with prudence, the risk of life-threatening complications exists. Although most adverse events are small and should be treated with caution, the risk of life-threatening toxicities should not be underestimated, especially given the subtle and unusual indications that make early detection even more difficult. Treatment for these issues is difficult and necessitates a multidisciplinary approach involving not only oncologists but also other internal medicine doctors to guarantee quick diagnosis and treatment. This study’s purpose is to give a fundamental overview of immunotherapy and cancer-related side effect management strategies.

Cell-free protein synthesis of influenza virus hemagglutinin HA2-integrated virosomes for siRNA delivery

It is well known that the difficulty of siRNA therapeutic application is the lack of safe and effective delivery vector. Virosome is a nano vesicle composed of lipid membrane and membrane protein. It retains fusion protein without virus genetic material, and therefore has the reduced immunogenicity compared with viral vector. Virosomes have the potential to deliver protein and nucleic acid drugs, but the traditional preparation method of virosomes is quite limited. In this study, we firstly proposed to synthesize influenza virus hemagglutinin HA2 virosomes by cell-free protein synthesis. In this study, liposomes provided the hydrophobic lipid bilayer environment for the formation of HA2 protein multimer, which inhibited the aggregation of hydrophobic HA2 and improved HA2 protein expression. Chitosan as a rigid core adsorbed siRNA and improved the encapsulation efficiency of siRNA. In conclusion, the cell-free protein synthesis was used to prepare HA2 virosomes, which paves the way for constructing a novel nano vector with high delivery efficiency and biosafety for the delivery of siRNA.

ROS-triggered nanoinducer based on dermatan sulfate enhances immunogenic cell death in melanoma

Due to its complexity, diversity and heterogeneity, melanoma is a kind of malignant tumor. It has been proved that the enhancement of anti-tumor immune response such as immunogenic cell death (ICD) is an important therapeutic strategy. In previous studies, we confirmed that dermatan sulfate (DS) from skin tissue could specifically homing to melanoma B16F10 cells. In this study, we propose a nanoinducer (DOX/ADS NP) based on a functional DS for melanoma. This nanosystem is composed of DS as framework, aromatic thioketal derivative (ATK) as functional grafting unit and doxorubicin (DOX) designed as an ICD inducer. Through the intermolecular interaction between DOX and ATK, DOX/ADS NP with specific-homing, high-loading and ROS-triggering release was obtained via self-assemble. Compared with free DOX and non-functionalized nanomedicine, DOX/ADS NP could release DOX into B16F10 cells better, and strongly induce the translocation of calreticulin (CRT) to the cell membrane. CRT is a marker of ICD, also as a "eat me" signal to stimulate the maturation and antigen presentation of dendritic cells. Therefore, a series of subsequent immune responses were activated: maturation of dendritic cells, T cells proliferation, increased tumor-infiltrating CTLs and the ratio of CTLs to Tregs, and up-regulated cytotoxic cytokine expression. In conclusion, DOX/ADS NP promoted ICD-associated immune response through more specific targeting effect and sensitive responsive DOX release, achieving better inhibitory effect on melanoma than free DOX and other nanoformulation. This biomimetic ICD nanoinducer based on DS is expected to provide new strategies and references for the treatment of melanoma.

Targeting Immunosuppressive Tumor-Associated Macrophages Using Innate T Cells for Enhanced Antitumor Reactivity

The field of T cell-based and chimeric antigen receptor (CAR)-engineered T (CAR-T) cell-based antitumor immunotherapy has seen substantial developments in the past decade; however, considerable issues, such as graft-versus-host disease (GvHD) and tumor-associated immunosuppression, have proven to be substantial roadblocks to widespread adoption and implementation. Recent developments in innate immune cell-based CAR therapy have opened several doors for the expansion of this therapy, especially as it relates to allogeneic cell sources and solid tumor infiltration. This study establishes in vitro killing assays to examine the TAM-targeting efficacy of MAIT, iNKT, and γδT cells. This study also assesses the antitumor ability of CAR-engineered innate T cells, evaluating their potential adoption for clinical therapies. The in vitro trials presented in this study demonstrate the considerable TAM-killing abilities of all three innate T cell types, and confirm the enhanced antitumor abilities of CAR-engineered innate T cells. The tumor- and TAM-targeting capacity of these innate T cells suggest their potential for antitumor therapy that supplements cytotoxicity with remediation of tumor microenvironment (TME)-immunosuppression.

Contribution of the Tumor Microenvironment to Metabolic Changes Triggering Resistance of Multiple Myeloma to Proteasome Inhibitors

Virtually all patients with multiple myeloma become unresponsive to treatment with proteasome inhibitors over time. Relapsed/refractory multiple myeloma is accompanied by the clonal evolution of myeloma cells with heterogeneous genomic aberrations, diverse proteomic and metabolic alterations, and profound changes of the bone marrow microenvironment. However, the molecular mechanisms that drive resistance to proteasome inhibitors within the context of the bone marrow microenvironment remain elusive. In this review article, we summarize the latest knowledge about the complex interaction of malignant plasma cells with its surrounding microenvironment. We discuss the pivotal role of metabolic reprograming of malignant plasma cells within the tumor microenvironment with a subsequent focus on metabolic rewiring in plasma cells upon treatment with proteasome inhibitors, driving multiple ways of adaptation to the treatment. At the same time, mutual interaction of plasma cells with the surrounding tumor microenvironment drives multiple metabolic alterations in the bone marrow. This provides a tumor-promoting environment, but at the same time may offer novel therapeutic options for the treatment of relapsed/refractory myeloma patients.

From Tumor Cells to Endothelium and Gut Microbiome: A Complex Interaction Favoring the Metastasis Cascade

Metastasis is a complicated process through which tumor cells disseminate to distant organs and adapt to novel tumor microenvironments. This multi-step cascade relies on the accumulation of genetic and epigenetic alterations within the tumor cells as well as the surrounding non-tumor stromal cells. Endothelial cells constitute a major player in promoting metastasis formation either by inducing the growth of tumor cells or by directing them towards dissemination in the blood or lymph. In fact, the direct and indirect interactions between tumor and endothelial cells were shown to activate several mechanisms allowing cancer cells’ invasion and extravasation. On the other side, gastrointestinal cancer development was shown to be associated with the disruption of the gut microbiome. While several proposed mechanisms have been investigated in this regard, gut and tumor-associated microbiota were shown to impact the gut endothelial barrier, increasing the dissemination of bacteria through the systemic circulation. This bacterial dislocation allows the formation of an inflammatory premetastatic niche in the distant organs promoting the metastatic cascade of primary tumors. In this review, we discuss the role of the endothelial cells in the metastatic cascade of tumors. We will focus on the role of the gut vascular barrier in the regulation metastasis. We will also discuss the interaction between this vascular barrier and the gut microbiota enhancing the process of metastasis. In addition, we will try to elucidate the different mechanisms through which this bacterial dislocation prepares the favorable metastatic niche at distant organs allowing the dissemination and successful deposition of tumor cells in the new microenvironments. Finally, and given the promising results of the studies combining immune checkpoint inhibitors with either microbiota alterations or anti-angiogenic therapy in many types of cancer, we will elaborate in this review the complex interaction between these 3 factors and their possible therapeutic combination to optimize response to treatment.

A PDE Model of Breast Tumor Progression in MMTV-PyMT Mice

The evolution of breast tumors greatly depends on the interaction network among different cell types, including immune cells and cancer cells in the tumor. This study takes advantage of newly collected rich spatio-temporal mouse data to develop a data-driven mathematical model of breast tumors that considers cells' location and key interactions in the tumor. The results show that cancer cells have a minor presence in the area with the most overall immune cells, and the number of activated immune cells in the tumor is depleted over time when there is no influx of immune cells. Interestingly, in the case of the influx of immune cells, the highest concentrations of both T cells and cancer cells are in the boundary of the tumor, as we use the Robin boundary condition to model the influx of immune cells. In other words, the influx of immune cells causes a dominant outward advection for cancer cells. We also investigate the effect of cells' diffusion and immune cells' influx rates in the dynamics of cells in the tumor micro-environment. Sensitivity analyses indicate that cancer cells and adipocytes' diffusion rates are the most sensitive parameters, followed by influx and diffusion rates of cytotoxic T cells, implying that targeting them is a possible treatment strategy for breast cancer.

A review on targeting tumor microenvironment: The main paradigm shift in the mAb-based immunotherapy of solid tumors

Monoclonal antibodies (mAbs) as biological macromolecules have been remarked the large and growing pipline of the pharmaceutical market and also the most promising tool in modern medicine for cancer therapy. These therapeutic entities, which consist of whole mAbs, armed mAbs (i.e., antibody-toxin conjugates, antibody-drug conjugates, and antibody-radionuclide conjugates), and antibody fragments, mostly target tumor cells. However, due to intrinsic heterogeneity of cancer diseases, tumor cells targeting mAb have been encountered with difficulties in their unpredictable efficacy as well as variability in remission and durable clinical benefits among cancer patients. To address these pitfalls, the area has undergone two major evolutions with the intent of minimizing anti-drug responses and addressing limitations experienced with tumor cell-targeted therapies. As a novel hallmark of cancer, the tumor microenvironment (TME) is becoming the great importance of attention to develop innovative strategies based on therapeutic mAbs. Here, we underscore innovative strategies targeting TME by mAbs which destroy tumor cells indirectly through targeting vasculature system (e.g., anti-angiogenesis), immune system modulation (i.e., stimulation, suppression, and depletion), the targeting and blocking of stroma-based growth signals (e.g., cancer-associated fibroblasts), and targeting cancer stem cells, as well as, their effector mechanisms, clinical uses, and relevant mechanisms of resistance.

Counteractive Effects of IL-33 and IL-37 on Inflammation in Osteoarthritis

Osteoarthritis (OA) is a chronic inflammatory disease where pro-inflammatory cytokines, damage-associated molecular patterns (DAMPs), and macrophages play a crucial role. However, the interactive role of these mediators, the exact cause precipitating OA and definitive treatment for OA are not known yet. Moreover, the interactive role of interleukin (IL)-33 and IL-37 with other factors in the pathogenesis of OA has not been discussed elaborately. In this study, we analyzed the expression of IL-33 and IL-37 in human OA knee and hip joint cartilage tissues. The effect of increased DAMPs, IL-33, and IL-37 on IL-6, tumor necrosis factor (TNF)-α, toll-like receptors (TLRs), and matrix metalloproteinases (MMPs) expression was delineated using human normal and osteoarthritic chondrocytes. The effect of anti-inflammatory cytokine IL-37 on various mediators of inflammation in the presence of IL-33, rHMGB-1, and LPS was investigated to delineate the effects of IL-37. Further, the effects of blocking IL-33 downstream signaling and the effects of IL-33 and IL-37 on macrophage polarization were assessed along with examining the macrophage phenotypes in human OA cartilage tissues. The results of this study revealed increased expression of IL-33 in OA cartilage and that IL-33 increases IL-6, TNF-α, TLRs, and MMPs expression and favors phenotypic conversion towards the M1 phenotype, while IL-37 and blocking IL-33 receptor ST2 have opposite effects. Overall, the results suggest that blocking IL-33 and increasing IL-37 act synergistically to attenuate inflammation and might serve as potential therapeutics in OA.

Correlation between amino acid metabolism and self-renewal of cancer stem cells: Perspectives in cancer therapy

Cancer stem cells (CSCs) possess self-renewal and differentiation potential, which may be related to recurrence, metastasis, and radiochemotherapy resistance during tumor treatment. Understanding the mechanisms via which CSCs maintain self-renewal may reveal new therapeutic targets for attenuating CSC resistance and extending patient life-span. Recent studies have shown that amino acid metabolism plays an important role in maintaining the self-renewal of CSCs and is involved in regulating their tumorigenicity characteristics. This review summarizes the relationship between CSCs and amino acid metabolism, and discusses the possible mechanisms by which amino acid metabolism regulates CSC characteristics particularly self-renewal, survival and stemness. The ultimate goal is to identify new targets and research directions for elimination of CSCs.

Clinical and Biological Variables Influencing Outcome in Patients with Advanced Non-Small Cell Lung Cancer (NSCLC) Treated with Anti-PD-1/PD-L1 Antibodies: A Prospective Multicentre Study

Introduction: Immune checkpoint inhibitors (ICIs) have become the standard of treatment for patients with non-small cell lung cancer (NSCLC). However, there are still many uncertainties regarding the selection of the patient who could benefit more from this treatment. This study aims to evaluate the prognostic and predictive role of clinical and biological variables in unselected patients with advanced NSCLC candidates to receive ICIs. Methods: This is an observational and prospective study. The primary objective is the evaluation of the relationship between clinical and biological variables and the response to ICIs. Secondary objectives included: safety; assessment of the relationship between clinical and biological parameters/concomitant treatments and progression-free survival at 6 months and overall survival at 6 and 12 months. Nomograms to predict these outcomes have been generated. Results: A total of 166 patients were included. An association with response was found in the presence of the high immunohistochemical PD-L1 expression, squamous cell histotype, and early line of treatment, whereas a higher probability of progression was seen in the presence of anemia, high LDH values and neutrophil/lymphocyte ratio (NLR), pleural involvement, and thrombosis before treatment. The nomogram showed that anemia, PD-L1 expression, NLR, and LDH represented the most informative predictor as regards the three parameters of interest. Conclusions: In the era of personalized medicine, the results are useful for stratifying the patients and tailoring the treatments, considering both the histological findings and the clinical features of the patients.

Extracellular Vesicle-Mediated Mitochondrial Reprogramming in Cancer

Simple Summary

Mitochondria are important organelles involved in several key cellular processes including energy production and cell death regulation. For this reason, it is unsurprising that mitochondrial function and structure are altered in several pathological states including cancer. Cancer cells present variate strategies to generate sufficient energy to sustain their high proliferation rates. These adaptative strategies can be mediated by extracellular signals such as extracellular vesicles. These vesicles can alter recipient cellular behavior by delivering their molecular cargo. This review explores the different EV-mediated mitochondrial reprogramming mechanisms supporting cancer survival and progression.

Abstract

Altered metabolism is a defining hallmark of cancer. Metabolic adaptations are often linked to a reprogramming of the mitochondria due to the importance of these organelles in energy production and biosynthesis. Cancer cells present heterogeneous metabolic phenotypes that can be modulated by signals originating from the tumor microenvironment. Extracellular vesicles (EVs) are recognized as key players in intercellular communications and mediate many of the hallmarks of cancer via the delivery of their diverse biological cargo molecules. Firstly, this review introduces the most characteristic changes that the EV-biogenesis machinery and mitochondria undergo in the context of cancer. Then, it focuses on the EV-driven processes which alter mitochondrial structure, composition, and function to provide a survival advantage to cancer cells in the context of the hallmarks of cancers, such as altered metabolic strategies, migration and invasiveness, immune surveillance escape, and evasion of apoptosis. Finally, it explores the as yet untapped potential of targeting mitochondria using EVs as delivery vectors as a promising cancer therapeutic strategy.

Targeting lactate metabolism and glycolytic pathways in the tumor microenvironment by natural products: A promising strategy in combating cancer

Anticancer drugs are not purely effective because of their toxicity, side effects, high cost, inaccessibility, and associated resistance. On the other hand, cancer is a complex public health problem that could intelligently adopt different signaling pathways and alter the body's metabolism to escape from the immune system. One of the cancer strategies to metastasize is modifying pH in the tumor microenvironment, ranging between 6.5 and 6.9. As a powerful determiner, lactate is responsible for this acidosis. It is involved in immune stimulation, including innate and adaptive immunity, apoptotic-related factors (Bax/Bcl-2, caspase), and glycolysis pathways (e.g., GLUT-1, PKM2, PFK, HK2, MCT-1, and LDH). Lactate metabolism, in turn, is interconnected with several dysregulated signaling mediators, including PI3K/Akt/mTOR, AMPK, NF-κB, Nrf2, JAK/STAT, and HIF-1α. Because of lactate's emerging and critical role, targeting lactate production and its transporters is important for preventing and managing tumorigenesis. Hence, exploring and developing novel promising anticancer agents to minimize human cancers is urgent. Based on numerous studies, natural secondary metabolites as multi-target alternative compounds with health-promoting properties possess more high effectiveness and low side effects than conventional agents. Besides, the mechanism of multi-targeted natural sources is related to lactate production and cancer-associated cross-talked factors. This review focuses on targeting the lactate metabolism/transporters, and lactate-associated mediators, including glycolytic pathways. Besides, interconnected mediators to lactate metabolism are also targeted by natural products. Accordingly, plant-derived secondary metabolites are introduced as alternative therapies in combating cancer through modulating lactate metabolism and glycolytic pathways.

The acidic tumour microenvironment: Manipulating the immune response to elicit escape

The success of cancer treatment relies on the composition of the tumour microenvironment which is comprised of tumour cells, blood vessels, stromal cells, immune cells, and extracellular matrix components. Barriers to effective cancer treatment need to be overcome, and the acidic microenvironment of the tumour provides a key target for treatment. This review intends to provide an overview of the effects that low extracellular pH has on components of the tumour microenvironment and how they contribute to immune escape. Further, potential therapeutic targets will be discussed.

N6-Methyladenosine-Related lncRNAs Are Potential Prognostic Biomarkers and Correlated With Tumor Immune Microenvironment in Osteosarcoma

N6-methyladenosine (m6A) and long non-coding RNAs (lncRNAs) play vital roles in the prognostic value and immune microenvironment of malignant tumors. Here, we constructed a m6A-related lncRNA signature in osteosarcoma samples from TCGA dataset and analyzed the association of the signature with tumor immune microenvironment. m6A-related lncRNAs were identified by performing Pearson's correlation analysis and were used to construct a novel m6A-related lncRNA signature in osteosarcoma. Validation in testing and entire cohorts confirmed the satisfactory accuracy of the risk signature. Principal-component analysis verifies the grouping ability of the risk signature. Functional enrichment analyses connected immune with the risk signature based on the six m6A-related lncRNAs. When patients were separated into high- and low-risk group based on their risk scores, we found that patients in the high-risk group had lower stromal scores, immune scores, and ESTIMATE scores, while the tumor purity was higher in the high-risk group than that in the low-risk group. As for immune cell infiltration, the proportion of monocytes was significantly higher in the low-risk group than that in the high-risk group. Of the six lncRNAs, AC004812.2 was a protective factor in osteosarcoma and low expression of AC004812.2 predicted worse overall survival. Overexpression of AC004812.2 inhibited 143B cell proliferation and increased the expression levels of IGF2BP1 and YTHDF1. In all, our m6A-related lncRNA signature was a potential prognostic biomarker and correlated with tumor immune microenvironment and immune cell infiltration, and AC004812.2 might be an important regulator of m6A modification and a promising therapeutic target in osteosarcoma.

Anticancer Activity of Urease Mimetic Cobalt (III) Complexes on A549-Lung Cancer Cells: Targeting the Acidic Microenvironment

Tumour cells maintain a local hypoxic and acidic microenvironment which plays a crucial role in cancer progression and drug resistance. Urease is a metallohydrolases that catalyses the hydrolysis of urea into ammonia and carbon dioxide, causing an abrupt increase of pH. This enzymatic activity can be employed to target the acidic tumour microenvironment. In this study, we present the anticancer activities of urease mimetic cobalt (III) complexes on A549 cells. The cells were treated with different doses of cobalt (III) complexes to observe the cytotoxicity. The change in cellular morphology was observed using an inverted microscope. The cell death induced by these complexes was analysed through ATP proliferation, LDH release and caspase 3/7 activity. The effect of extracellular alkalinization by the cobalt (III) complexes on the efficacy of the weakly basic drug, doxorubicin (dox) was also evaluated. This combination therapy of dox with cobalt (III) complexes resulted in enhanced apoptosis in A549 cells, as evidenced by elevated caspase 3/7 activity in treated groups. The study confirms the urease mimicking anticancer activity of cobalt (III) complexes by neutralizing the tumour microenvironment. This study will motivate the applications of transition metal-based enzyme mimics in targeting the tumour microenvironment for effective anticancer treatments.

Korean Red Ginseng Enhances Immunotherapeutic Effects of NK Cells via Eosinophils in Metastatic Liver Cancer Model

Metastasis decreases the survival rate of patients with liver cancer. Therefore, novel anti-metastatic strategies are needed. Korean Red Ginseng (KRG) is often ingested as a functional food with an immune-boosting effect. We investigated a combination of KRG and natural killer (NK) cells as a novel immunotherapy approach. SK-Hep1 cells were injected into the tail vein of NRGA mice to establish an experimental metastasis model. KRG, NK cells, or a combination of KRG and NK cells were administered. Tumor growth was observed using an in vivo imaging system, and metastatic lesions were evaluated by histological analysis and immunohistochemistry. Bioluminescence intensity was lower in the KRG and NK cell combination group than in the other groups, indicating that the combination treatment suppressed the progression of metastasis. CD56 expression was used as a NK cell marker and hematological analysis was performed. The combination treatment also decreased the expression of matrix metalloproteinases and the area of metastatic lesions in liver and bone tissues, as well as increased the eosinophil count. Expression of cytokines-related eosinophils and NK cells was determined by Western blotting analysis. The expression of interleukin 33 (IL33) was induced by the combination of KRG and NK cells. High IL33 expression was associated with prolonged overall survival in the Kaplan–Meier plotter. Our results suggest that KRG enhances the immune activity of NK cells by IL-33 through eosinophils and suppresses metastatic liver cancer progression.

Glycolysis Changes the Microenvironment and Therapeutic Response Under the Driver of Gene Mutation in Esophageal Adenocarcinoma

Background: Esophageal cancer is one of the most leading and lethal malignancies. Glycolysis and the tumor microenvironment (TME) are responsible for cancer progressions. We aimed to study the relationships between glycolysis, TME, and therapeutic response in esophageal adenocarcinoma (EAC). Materials and Methods: We used the ESTIMATE algorithm to divide EAC patients into ESTIMATE ^high and ESTIMATE ^low groups based on the gene expression data downloaded from TCGA. Weighted gene co-expression network analysis (WGCNA) and Gene Set Enrichment Analysis (GSEA) were performed to identify different glycolytic genes in the TME between the two groups. The prognostic gene signature for overall survival (OS) was established through Cox regression analysis. Impacts of glycolytic genes on immune cells were assessed and validated. Next, we conducted the glycolytic gene mutation analysis and drug therapeutic response analysis between the two groups. Finally, the GEO database was employed to validate the impact of glycolysis on TME in patients with EAC. Results: A total of 78 EAC patients with gene expression profiles and clinical information were included for analysis. Functional enrichment results showed that the genes between ESTIMATE ^high and ESTIMATE ^low groups (N = 39, respectively) were strongly related with glycolytic and ATP/ADP metabolic pathways. Patients in the low-risk group had probabilities to survive longer than those in the high-risk group (p < 0.001). Glycolytic genes had significant impacts on the components of immune cells in TME, especially on the T-cells and dendritic cells. In the high-risk group, the most common mutant genes were TP53 and TTN, and the most frequent mutation type was missense mutation. Glycolysis significantly influenced drug sensitivity, and high tumor mutation burden (TMB) was associated with better immunotherapeutic response. GEO results confirmed that glycolysis had significant impacts on immune cell contents in TME. Conclusion: We performed a comprehensive study of glycolysis and TME and demonstrated that glycolysis could influence the microenvironment and drug therapeutic response in EAC. Evaluation of the glycolysis pattern could help identify the individualized therapeutic regime.

Immune response of silver pomfret (Pampus argenteus) to Amyloodinium ocellatum infection

Amyloodinium ocellatum (AO) infection in silver pomfret (Pampus argenteus) causes extensive mortality. Insufficient information exists on the molecular immune response of silver pomfret to AO infestation, so herein we simulated the process of silver pomfret being infected by AO. Translucent trophosomes were observed on the gills of AO-infected fish. Transcriptome profiling was performed to investigate the effects of AO infection on the gill, kidney complex and spleen. Overall, 404,412,298 clean reads were obtained, assembling into 96,341 unigenes, which were annotated against public databases. In total, 2730 differentially expressed genes were detected, and few energy- and immune-related genes were further assessed using RT-qPCR. Moreover, activities of three immune-related (SOD, AKP and ACP) and three energy-related (PKM, LDH and GCK) enzymes were determined. AO infection activated the immune system and increased interleukin-1 beta and immunoglobulin M heavy chain levels. Besides, the PPAR signalling pathway was highly enriched, which played a role in improving immunity and maintaining homeostasis. AO infection also caused dyspnoea, leading to extensive lactic acid accumulation, potentially contributing towards a strong immune response in the host. Our data improved our understanding regarding the immune response mechanisms through which fish coped with parasitic infections and may help prevent high fish mortality in aquaculture.

Interventional Radiology Image-Guided Locoregional Therapies (LRTs) and Immunotherapy for the Treatment of HCC

Image-guided locoregional therapies (LRTs) are a crucial asset in the treatment of hepatocellular carcinoma (HCC), which has proven to be characterized by an impaired antitumor immune status. LRTs not only directly destroy tumor cells but also have an immunomodulating role, altering the tumor microenvironment with potential systemic effects. Nevertheless, the immune activation against HCC induced by LRTs is not strong enough on its own to generate a systemic significant antitumor response, and it is incapable of preventing tumor recurrence. Currently, there is great interest in the possibility of combining LRTs with immunotherapy for HCC, as this combination may result in a mutually beneficial and synergistic relationship. On the one hand, immunotherapy could amplify and prolong the antitumoral immune response of LRTs, reducing recurrence cases and improving outcome. On the other hand, LTRs counteract the typical immunosuppressive HCC microenvironment and status and could therefore enhance the efficacy of immunotherapy. Here, after reviewing the current therapeutic options for HCC, we focus on LRTs, describing for each of them the technique and data on its effect on the immune system. Then, we describe the current status of immunotherapy and finally report the recently published and ongoing clinical studies testing this combination.

Mechanisms of Immunosuppressive Tumor Evasion: Focus on Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is a malignancy with high heterogeneity in its biological features and treatments. Although the overall survival (OS) of patients with ALL has recently improved considerably, owing to the application of conventional chemo-therapeutic agents, approximately 20% of the pediatric cases and 40-50% of the adult patients relapse during and after the treatment period. The potential mechanisms that cause relapse involve clonal evolution, innate and acquired chemoresistance, and the ability of ALL cells to escape the immune-suppressive tumor response. Currently, immunotherapy in combination with conventional treatment is used to enhance the immune response against tumor cells, thereby significantly improving the OS in patients with ALL. Therefore, understanding the mechanisms of immune evasion by leukemia cells could be useful for developing novel therapeutic strategies.

Interplay between Cellular and Non-Cellular Components of the Tumour Microenvironment in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common and lethal cancers worldwide. Currently, treatments available for advanced HCC provide dismal chances of survival, thus there is an urgent need to develop more effective therapeutic strategies. While much of the focus of recent decades has been on targeting malignant cells, promising results have emerged from targeting the tumour microenvironment (TME). The extracellular matrix (ECM) is the main non-cellular component of the TME and it profoundly changes during tumorigenesis to promote the growth and survival of malignant cells. Despite this, many in vitro models for drug testing fail to consider the TME leading to a high failure rate in clinical trials. Here, we present an overview of the function and properties of the ECM in the liver and how these change during malignant transformation. We also discuss the relationship between immune cells and ECM in the TME in HCC. Lastly, we present advanced, 3D culture techniques of cancer modelling and argue that the incorporation of TME components into these is essential to better recapitulate the complex interactions within the TME.

Metabolic Molecule PLA2G2D Is a Potential Prognostic Biomarker Correlating With Immune Cell Infiltration and the Expression of Immune Checkpoint Genes in Cervical Squamous Cell Carcinoma

Cervical squamous cell carcinoma (CSCC) is the major pathological type of cervical cancer (CC), the second most prevalent reproductive system malignant tumor threatening the health of women worldwide. The prognosis of CSCC patients is largely affected by the tumor immune microenvironment (TIME); however, the biomarker landscape related to the immune microenvironment of CSCC and patient prognosis is less characterized. Here, we analyzed RNA-seq data of CSCC patients from The Cancer Genome Atlas (TCGA) database by dividing it into high- and low-immune infiltration groups with the MCP-counter and ESTIMATE R packages. After combining weighted gene co-expression network analysis (WGCNA) and differentially expressed gene (DEG) analysis, we found that PLA2G2D, a metabolism-associated gene, is the top gene positively associated with immune infiltration and patient survival. This finding was validated using data from The Cancer Genome Characterization Initiative (CGCI) database and further confirmed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Finally, multiplex immunohistochemistry (mIHC) was performed to confirm the differential infiltration of immune cells between PLA2G2D-high and PLA2G2D-low tumors at the protein level. Our results demonstrated that PLA2G2D expression was significantly correlated with the infiltration of immune cells, especially T cells and macrophages. More importantly, PLA2G2D-high tumors also exhibited higher infiltration of CD8+ T cells inside the tumor region than PLA2G2D-low tumors. In addition, PLA2G2D expression was found to be positively correlated with the expression of multiple immune checkpoint genes (ICPs). Moreover, based on other immunotherapy cohort data, PLA2G2D high expression is correlated with increased cytotoxicity and favorable response to immune checkpoint blockade (ICB) therapy. Hence, PLA2G2D could be a novel potential biomarker for immune cell infiltration, patient survival, and the response to ICB therapy in CSCC and may represent a promising target for the treatment of CSCC patients.

TIGIT Induces (CD3+) T Cell Dysfunction in Colorectal Cancer by Inhibiting Glucose Metabolism

T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) is an immunosuppressive receptor expressed on the surface of immune cells, suppressing immune responses by activating the intracellular negative regulatory signals. TIGIT plays an important role in the pathogenesis of various tumors, but its immune escape in colorectal cancer remains unclear. We found that the proportion of CD3+TIGIT+ T cells was increased in peripheral blood and cancer tissue in colorectal cancer patients when compared with the healthy donors. These cells exhibited functional defects, low proliferative activity, impaired cytokine production and reduced glucose metabolism. A strong association was also observed between the elevated TIGIT expression and poor prognosis in this cohort. In the in vitro co-culture assays of T cells and tumor cells, the suppressed glucose metabolic activity of T cells was reversed by TIGIT blockade. In addition, this blockade induced the apoptosis and reduced G2/M transit in tumor cells. The antitumor efficacy of TIGIT Ab therapy was further demonstrated in a human colorectal xenograft mice model while co-blockers of TIGIT and PD-1 exhibited synergistic suppressing effects on tumor growth. These results suggest that while TIGIT induces CD3+ T cell dysfunction in colorectal cancer, co-targeting TIGIT and PD-1 can lead to an effective antitumor response and may serve as a novel therapeutic strategy for colorectal patients.

Pan-cancer Analysis of NEDD4L and Its Tumor Suppressor Effects in Clear Cell Renal Cell Carcinoma

The expression level of NEDD4L, an E3 ubiquitin ligase, has changed significantly in human cancers. In this study, we aimed to study the expression of NEDD4L in pan-carcinoma and its function in malignant tumors. We analyzed the gene expression level of NEDD4L in pan-cancer from The Cancer Genome Atlas (TCGA) microarray data set, the correlation between gene expression and overall survival, disease-specific survival, and tumor immune microenvironment changes. NEDD4L expression changes in half of the cancer types. Low expression of NEDD4L gene predicts poor overall survival and disease-specific survival (DSS) in renal clear cell carcinoma (KIRC) and renal chromophobe cell carcinoma (KIRP). NEDD4L is negatively related to interstitial cell infiltration and immune cell infiltration in most common cancers. Furthermore, the low expression of NEDD4L was verified in our clear cell renal cell carcinoma (ccRCC) clinical tissues. In ccRCC cells, NEDD4L overexpression significantly reduced cell proliferation and migration. In the functional analysis, we proved that NEDD4L could inhibit ERBB3 and MAPK signaling pathways. When cells are deficient in nutrition, NEDD4L promoted the degradation of the autophagy regulatory protein ULK1. Our study provides novel insights into the role of NEDD4L in pan-cancer. NEDD4L may play a tumor suppressor effect in ccRCC, through tumor immune regulation and ubiquitination of key intracellular kinases.

Transferrin-Conjugated Erianin-Loaded Liposomes Suppress the Growth of Liver Cancer by Modulating Oxidative Stress

Background

Liver cancer is one of the most malignant human cancers, with few treatments and a poor prognosis. Erianin (ERN) is a natural compound with multiple pharmacological activities that has been reported to have numerous excellent effects against liver cancer in experimental systems. However, its application in vivo has been limited due to its poor aqueous solubility and numerous off-target effects. This study aimed to improve the therapeutic efficacy of ERN by developing novel ERN-loaded tumor-targeting nanoparticles.

Results

In this study, ERN was loaded into liposomes by ethanol injection (LP-ERN), and the resulting LP-ERN nanoparticles were treated with transferrin to form Tf-LP-ERN to improve the solubility and enhance the tumor-targeting of ERN. LP-ERN and Tf-LP-ERN nanoparticles had smooth surfaces and a uniform particle size, with particle diameters of 62.60 nm and 88.63 nm, respectively. In HepG2 and SMMC-7721 cells, Tf-LP-ERN induced apoptosis, decreased mitochondrial membrane potentials and increased ERN uptake more effectively than free ERN and LP-ERN. In xenotransplanted mice, Tf-LP-ERN inhibited tumor growth, but had a minimal effect on body weight and organ morphology. In addition, Tf-LP-ERN nanoparticles targeted tumors more effectively than free ERN and LP-ERN nanoparticles, and in tumor tissues Tf-LP-ERN nanoparticles promoted the cleavage PARP-1, caspase-3 and caspase-9, increased the expression levels of Bax, Bad, PUMA, and reduced the expression level of Bcl-2. Moreover, in the spleen of heterotopic tumor model BALB/c mice, ERN, LP-ERN and Tf-LP-ERN nanoparticles increased the expression levels of Nrf2, HO-1, SOD-1 and SOD-2, but reduced the expression levels of P-IKKα+β and P-NF-κB, with Tf-LP-ERN nanoparticles being most effective in this regard. Tf-LP-ERN nanoparticles also regulated the expression levels of TNF-α, IL-10 and CCL11 in serum.

Conclusion

Tf-LP-ERN nanoparticles exhibited excellent anti-liver cancer activity in vivo and in vitro by inducing cellular apoptosis, exhibiting immunoregulatory actions, and targeting tumor tissues, and did so more effectively than free ERN and LP-ERN nanoparticles. These results suggest that the clinical utility of a Tf-conjugated LP ERN-delivery system for the treatment of liver cancer warrants exploration.

Genome Scale Modeling to Study the Metabolic Competition between Cells in the Tumor Microenvironment

The tumor's physiology emerges from the dynamic interplay of numerous cell types, such as cancer cells, immune cells and stromal cells, within the tumor microenvironment. Immune and cancer cells compete for nutrients within the tumor microenvironment, leading to a metabolic battle between these cell populations. Tumor cells can reprogram their metabolism to meet the high demand of building blocks and ATP for proliferation, and to gain an advantage over the action of immune cells. The study of the metabolic reprogramming mechanisms underlying cancer requires the quantification of metabolic fluxes which can be estimated at the genome-scale with constraint-based or kinetic modeling. Constraint-based models use a set of linear constraints to simulate steady-state metabolic fluxes, whereas kinetic models can simulate both the transient behavior and steady-state values of cellular fluxes and concentrations. The integration of cell- or tissue-specific data enables the construction of context-specific models that reflect cell-type- or tissue-specific metabolic properties. While the available modeling frameworks enable limited modeling of the metabolic crosstalk between tumor and immune cells in the tumor stroma, future developments will likely involve new hybrid kinetic/stoichiometric formulations.

Enhanced CXCR4 Expression of Human CD8Low T Lymphocytes Is Driven by S1P4

Although the human immune response to cancer is naturally potent, it can be severely disrupted as a result of an immunosuppressive tumor microenvironment. Infiltrating regulatory T lymphocytes contribute to this immunosuppression by inhibiting proliferation of cytotoxic CD8⁺ T lymphocytes, which are key to an effective anti-cancer immune response. Other important contributory factors are thought to include metabolic stress caused by the local nutrient deprivation common to many solid tumors. Interleukin-33 (IL-33), an alarmin released in reaction to cell damage, and sphingosine-1-phosphate (S1P) are known to control cell positioning and differentiation of T lymphocytes. In an in vitro model of nutrient deprivation, we investigated the influence of IL-33 and S1P receptor 4 (S1P₄) on the differentiation and migration of human CD8⁺ T lymphocytes. Serum starvation of CD8⁺ T lymphocytes induced a subset of CD8^Low and IL-33 receptor-positive (ST2L⁺) cells characterized by enhanced expression of the regulatory T cell markers CD38 and CD39. Both S1P₁ and S1P₄ were transcriptionally regulated after stimulation with IL-33. Moreover, expression of the chemokine receptor CXCR4 was increased in CD8⁺ T lymphocytes treated with the selective S1P₄ receptor agonist CYM50308. We conclude that nutrient deprivation promotes CD8^Low T lymphocytes, contributing to an immunosuppressive microenvironment and a poor anti-cancer immune response by limiting cytotoxic effector functions. Our results suggest that S1P₄ signaling modulation may be a promising target for anti-CXCR4 cancer immunotherapy.

Modulating tumor-associated macrophages to enhance the efficacy of immune checkpoint inhibitors: A TAM-pting approach

Tumor-associated macrophages (TAM) plasticity and diversity are both essential hallmarks of the monocyte-macrophage lineage and the tumor-derived inflammation. TAM exemplify the perfect adaptable cell with dynamic phenotypic modifications that reflect changes in their functional polarization status. Under several tumor microenvironment (TME)-related cues, TAM shift their polarization, hence promoting or halting cancer progression. Immune checkpoint inhibitors (ICI) displayed unprecedented clinical responses in various refractory cancers; but only approximately a third of patients experienced durable responses. It is, therefore, crucial to enhance the response rate of immunotherapy. Several mechanisms of resistance to ICI have been elucidated including TAM role with its essential immunosuppressive functions that reduce both anti-tumor immunity and the subsequent ICI efficacy. In the past few years, thorough research has led to a better understanding of TAM biology and innovative approaches can now be adapted through targeting macrophages' recruitment axis as well as TAM activation and polarization status within the TME. Some of these therapeutic strategies are currently being evaluated in several clinical trials in association with ICI agents. This combination between TAM modulation and ICI allows targeting TAM intrinsic immunosuppressive functions and tumor-promoting factors as well as overcoming ICI resistance. Hence, such strategies, with a better understanding of the mechanisms driving TAM modulation, may have the potential to optimize ICI efficacy.

The Role of Acidosis in the Pathogenesis of Severe Forms of COVID-19

COVID-19 has specific characteristics that distinguish this disease from many other infections. We suggest that the pathogenesis of severe forms of COVID-19 can be associated with acidosis. This review article discusses several mechanisms potentially linking the damaging effects of COVID-19 with acidosis and shows the existence of a vicious cycle between the development of hypoxia and acidosis in COVID-19 patients. At the early stages of the disease, inflammation, difficulty in gas exchange in the lungs and thrombosis collectively contribute to the onset of acidosis. In accordance with the Verigo-Bohr effect, a decrease in blood pH leads to a decrease in oxygen saturation, which contributes to the exacerbation of acidosis and results in a deterioration of the patient's condition. A decrease in pH can also cause conformational changes in the S-protein of the virus and thus lead to a decrease in the affinity and avidity of protective antibodies. Hypoxia and acidosis lead to dysregulation of the immune system and multidirectional pro- and anti-inflammatory reactions, resulting in the development of a "cytokine storm". In this review, we highlight the potential importance of supporting normal blood pH as an approach to COVID-19 therapy.

Transferrin-Conjugated Erianin-Loaded Liposomes Suppress the Growth of Liver Cancer by Modulating Oxidative Stress

Background

Liver cancer is one of the most malignant human cancers, with few treatments and a poor prognosis. Erianin (ERN) is a natural compound with multiple pharmacological activities that has been reported to have numerous excellent effects against liver cancer in experimental systems. However, its application in vivo has been limited due to its poor aqueous solubility and numerous off-target effects. This study aimed to improve the therapeutic efficacy of ERN by developing novel ERN-loaded tumor-targeting nanoparticles.

Results

In this study, ERN was loaded into liposomes by ethanol injection (LP-ERN), and the resulting LP-ERN nanoparticles were treated with transferrin to form Tf-LP-ERN to improve the solubility and enhance the tumor-targeting of ERN. LP-ERN and Tf-LP-ERN nanoparticles had smooth surfaces and a uniform particle size, with particle diameters of 62.60 nm and 88.63 nm, respectively. In HepG2 and SMMC-7721 cells, Tf-LP-ERN induced apoptosis, decreased mitochondrial membrane potentials and increased ERN uptake more effectively than free ERN and LP-ERN. In xenotransplanted mice, Tf-LP-ERN inhibited tumor growth, but had a minimal effect on body weight and organ morphology. In addition, Tf-LP-ERN nanoparticles targeted tumors more effectively than free ERN and LP-ERN nanoparticles, and in tumor tissues Tf-LP-ERN nanoparticles promoted the cleavage PARP-1, caspase-3 and caspase-9, increased the expression levels of Bax, Bad, PUMA, and reduced the expression level of Bcl-2. Moreover, in the spleen of heterotopic tumor model BALB/c mice, ERN, LP-ERN and Tf-LP-ERN nanoparticles increased the expression levels of Nrf2, HO-1, SOD-1 and SOD-2, but reduced the expression levels of P-IKKα+β and P-NF-κB, with Tf-LP-ERN nanoparticles being most effective in this regard. Tf-LP-ERN nanoparticles also regulated the expression levels of TNF-α, IL-10 and CCL11 in serum.

Conclusion

Tf-LP-ERN nanoparticles exhibited excellent anti-liver cancer activity in vivo and in vitro by inducing cellular apoptosis, exhibiting immunoregulatory actions, and targeting tumor tissues, and did so more effectively than free ERN and LP-ERN nanoparticles. These results suggest that the clinical utility of a Tf-conjugated LP ERN-delivery system for the treatment of liver cancer warrants exploration.

NAD+ metabolism controls growth inhibition by HIF1 in normoxia and determines differential sensitivity of normal and cancer cells

The hypoxia-induced transcription factor HIF1 inhibits cell growth in normoxia through poorly understood mechanisms. A constitutive upregulation of hypoxia response is associated with increased malignancy, indicating a loss of antiproliferative effects of HIF1 in cancer cells. To understand these differences, we examined a control of cell cycle in primary human cells with activated hypoxia response in normoxia. Activated HIF1 caused a global slowdown of cell cycle progression through G1, S and G2 phases leading to the loss of mitotic cells. Cell cycle inhibition required a prolonged HIF1 activation and was not associated with upregulation of p53 or the CDK inhibitors p16, p21 or p27. Growth inhibition by HIF1 was independent of its Asn803 hydroxylation or the presence of HIF2. Antiproliferative effects of hypoxia response were alleviated by inhibition of lactate dehydrogenase and more effectively, by boosting cellular production of NAD⁺, which was decreased by HIF1 activation. In comparison to normal cells, various cancer lines showed several fold-higher expression of NAMPT which is a rate-limiting enzyme in the main biosynthetic pathway for NAD⁺. Inhibition of NAMPT activity in overexpressor cancer cells sensitized them to antigrowth effects of HIF1. Thus, metabolic changes in cancer cells, such as enhanced NAD⁺ production, create resistance to growth-inhibitory activity of HIF1 permitting manifestation of its tumor-promoting properties.AbbreviationsDMOG: dimethyloxalylglycine, DM-NOFD: dimethyl N-oxalyl-D-phenylalanine, NMN: β-nicotinamide mononucleotide.

The Role of Gut Microbiota in Overcoming Resistance to Checkpoint Inhibitors in Cancer Patients: Mechanisms and Challenges

The introduction of immune checkpoint inhibitors has constituted a major revolution in the treatment of patients with cancer. In contrast with the traditional cytotoxic therapies that directly kill tumor cells, this treatment modality enhances the ability of the host’s immune system to recognize and target cancerous cells. While immune checkpoint inhibitors have been effective across multiple cancer types, overcoming resistance remains a key area of ongoing research. The gut microbiota and its role in cancer immunosurveillance have recently become a major field of study. Gut microbiota has been shown to have direct and systemic effects on cancer pathogenesis and hosts anti-tumor immune response. Many studies have also shown that the host microbiota profile plays an essential role in the response to immunotherapy, especially immune checkpoint inhibitors. As such, modulating this microbial environment has offered a potential path to overcome the resistance to immune checkpoint inhibitors. In this review, we will talk about the role of microbiota in cancer pathogenesis and immune-system activity. We will also discuss preclinical and clinical studies that have increased our understanding about the roles and the mechanisms through which microbiota influences the response to treatment with immune checkpoint inhibitors.

Acid-base transporters and pH dynamics in human breast carcinomas predict proliferative activity, metastasis, and survival

Breast cancer heterogeneity in histology and molecular subtype influences metabolic and proliferative activity and hence the acid load on cancer cells. We hypothesized that acid-base transporters and intracellular pH (pH_i) dynamics contribute inter-individual variability in breast cancer aggressiveness and prognosis. We show that Na⁺,HCO₃^- cotransport and Na⁺/H⁺ exchange dominate cellular net acid extrusion in human breast carcinomas. Na⁺/H⁺ exchange elevates pH_i preferentially in estrogen receptor-negative breast carcinomas, whereas Na⁺,HCO₃^- cotransport raises pH_i more in invasive lobular than ductal breast carcinomas and in higher malignancy grade breast cancer. HER2-positive breast carcinomas have elevated protein expression of Na⁺/H⁺ exchanger NHE1/SLC9A1 and Na⁺,HCO₃^- cotransporter NBCn1/SLC4A7. Increased dependency on Na⁺,HCO₃^- cotransport associates with severe breast cancer: enlarged CO₂/HCO₃^--dependent rises in pH_i predict accelerated cell proliferation, whereas enhanced CO₂/HCO₃^--dependent net acid extrusion, elevated NBCn1 protein expression, and reduced NHE1 protein expression predict lymph node metastasis. Accordingly, we observe reduced survival for patients suffering from luminal A or basal-like/triple-negative breast cancer with high SLC4A7 and/or low SLC9A1 mRNA expression. We conclude that the molecular mechanisms of acid-base regulation depend on clinicopathological characteristics of breast cancer patients. NBCn1 expression and dependency on Na⁺,HCO₃^- cotransport for pH_i regulation, measured in biopsies of human primary breast carcinomas, independently predict proliferative activity, lymph node metastasis, and patient survival.

CCDC137 Is a Prognostic Biomarker and Correlates With Immunosuppressive Tumor Microenvironment Based on Pan-Cancer Analysis

Background

The coiled-coil domain containing (CCDC) family proteins have important biological functions in various diseases. However, the coiled-coil domain containing 137 (CCDC137) was rarely studied. We aim to investigate the role of CCDC137 in pan-cancer.

Methods

CCDC137 expression was evaluated in RNA sequence expression profilers of pan-cancer and normal tissues from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) database. The influence of CCDC137 on the prognosis of tumor patients was analyzed using clinical survival data from TCGA. Function and pathway enrichment analysis was performed to explore the role of CCDC137 using the R package “clusterProfiler.” We further analyzed the correlation of immune cell infiltration score of TCGA samples and CCDC137 expression using TIMER2 online database.

Results

CCDC137 was over-expressed and associated with worse survival status in various tumor types. CCDC137 expression was positively correlated with tumor associated macrophages (TAMs) and cancer associated fibroblasts (CAFs) in Lower Grade Glioma (LGG) and Uveal Melanoma (UVM). In addition, high CCDC137 expression was positively correlated with most immunosuppressive genes, including TGFB1, PD-L1, and IL10RB in LGG and UVM.

Conclusions

Our study identified CCDC137 as an oncogene and predictor of worse survival in most tumor types. High CCDC137 may contribute to elevated infiltration of TAMs and CAFs and be associated with tumor immunosuppressive status.

Whole-transcriptome Analysis of Fully Viable Energy Efficient Glycolytic-null Cancer Cells Established by Double Genetic Knockout of Lactate Dehydrogenase A/B or Glucose-6-Phosphate Isomerase

BACKGROUND/AIM

Nearly all mammalian tumors of diverse tissues are believed to be dependent on fermentative glycolysis, marked by elevated production of lactic acid and expression of glycolytic enzymes, most notably lactic acid dehydrogenase (LDH). Therefore, there has been significant interest in developing chemotherapy drugs that selectively target various isoforms of the LDH enzyme. However, considerable questions remain as to the consequences of biological ablation of LDH or upstream targeting of the glycolytic pathway.

MATERIALS AND METHODS

In this study, we explore the biochemical and whole transcriptomic effects of CRISPR-Cas9 gene knockout (KO) of lactate dehydrogenases A and B [LDHA/B double KO (DKO)] and glucose-6-phosphate isomerase (GPI KO) in the human colon cancer cell line LS174T, using Affymetrix 2.1 ST arrays.

RESULTS

The metabolic biochemical profiles corroborate that relative to wild type (WT), LDHA/B DKO produced no lactic acid, (GPI KO) produced minimal lactic acid and both KOs displayed higher mitochondrial respiration, and minimal use of glucose with no loss of cell viability. These findings show a high biochemical energy efficiency as measured by ATP in glycolysis-null cells. Next, transcriptomic analysis conducted on 48,226 mRNA transcripts reflect 273 differentially expressed genes (DEGS) in the GPI KO clone set, 193 DEGS in the LDHA/B DKO clone set with 47 DEGs common to both KO clones. Glycolytic-null cells reflect up-regulation in gene transcripts typically associated with nutrient deprivation / fasting and possible use of fats for energy: thioredoxin interacting protein (TXNIP), mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2), PPARγ coactivator 1α (PGC-1α), and acetyl-CoA acyltransferase 2 (ACAA2). Other changes in non-ergometric transcripts in both KOs show losses in "stemness", WNT signaling pathway, chemo/radiation resistance, retinoic acid synthesis, drug detoxification, androgen/estrogen activation, and extracellular matrix reprogramming genes.

CONCLUSION

These findings demonstrate that: 1) The "Warburg effect" is dispensable, 2) loss of the LDHAB gene is not only inconsequential to viability but fosters greater mitochondrial energy, and 3) drugs that target LDHA/B are likely to be ineffective without a plausible combination second drug target.

Role of exosomes in the immune microenvironment of ovarian cancer

Exosomes are excretory vesicles that can deliver a variety of bioactive cargo molecules to the extracellular environment. Accumulating evidence demonstrates exosome participation in intercellular communication, immune response, inflammatory response and they even play an essential role in affecting the tumor immune microenvironment. The role of exosomes in the immune microenvironment of ovarian cancer is mainly divided into suppression and stimulation. On one hand exosomes can stimulate the innate and adaptive immune systems by activating dendritic cells (DCs), natural killer cells and T cells, allowing these immune cells exert an antitumorigenic effect. On the other hand, ovarian cancer-derived exosomes initiate cross-talk with immunosuppressive effector cells, which subsequently cause immune evasion; one of the hallmarks of cancer. Exosomes induce the polarization of macrophages in M2 phenotype and induce apoptosis of lymphocytes and DCs. Exosomes further activate additional immunosuppressive effector cells (myeloid-derived suppressor cells and regulatory T cells) that induce fibroblasts to differentiate into cancer-associated fibroblasts. Exosomes also induce the tumorigenicity of mesenchymal stem cells to exert additional immune suppression. Furthermore, besides mediating the intercellular communication, exosomes carry microRNAs (miRNAs), proteins and lipids to the tumor microenvironment, which collectively promotes ovarian cancer cells to proliferate, invade and tumors to metastasize. Studying proteins, lipids and miRNAs carried by exosomes could potentially be used as an early diagnostic marker of ovarian cancer for designing treatment strategies.

The emerging relationship between metabolism and DNA repair

The DNA damage response (DDR) consists of multiple specialized pathways that recognize different insults sustained by DNA and repairs them where possible to avoid the accumulation of mutations. While loss of activity of genes in the DDR has been extensively associated with cancer predisposition and progression, in recent years it has become evident that there is a relationship between the DDR and cellular metabolism. The activity of the metabolic pathways can influence the DDR by regulating the availability of substrates required for the repair process and the function of its players. Additionally, proteins of the DDR can regulate the metabolic flux through the major pathways such as glycolysis, tricarboxylic acid cycle (TCA) and pentose phosphate pathway (PPP) and the production of reactive oxygen species (ROS). This newly discovered connection bears great importance in the biology of cancer and represents a new therapeutic opportunity. Here we describe the nature of the relationship between DDR and metabolism and its potential application in the treatment of cancer. Keywords: DNA repair, metabolism, mitochondria.

GLUT1 Expression in Tumor-Associated Neutrophils Promotes Lung Cancer Growth and Resistance to Radiotherapy

Neutrophils are the most abundant circulating leucocytes and are essential for innate immunity. In cancer, pro- or antitumor properties have been attributed to tumor-associated neutrophils (TAN). Here, focusing on TAN accumulation within lung tumors, we identify GLUT1 as an essential glucose transporter for their tumor supportive behavior. Compared with normal neutrophils, GLUT1 and glucose metabolism increased in TANs from a mouse model of lung adenocarcinoma. To elucidate the impact of glucose uptake on TANs, we used a strategy with two recombinases, dissociating tumor initiation from neutrophil-specific Glut1 deletion. Loss of GLUT1 accelerated neutrophil turnover in tumors and reduced a subset of TANs expressing SiglecF. In the absence of GLUT1 expression by TANs, tumor growth was diminished and the efficacy of radiotherapy was augmented. Our results demonstrate the importance of GLUT1 in TANs, which may affect their pro- versus antitumor behavior. These results also suggest targeting metabolic vulnerabilities to favor antitumor neutrophils. SIGNIFICANCE: Lung tumor support and radiotherapy resistance depend on GLUT1-mediated glucose uptake in tumor-associated neutrophils, indicating that metabolic vulnerabilities should be considered to target both tumor cells as well as innate immune cells. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/9/2345/F1.large.jpg.

CD244+ polymorphonuclear myeloid‑derived suppressor cells reflect the status of peritoneal dissemination in a colon cancer mouse model

Despite the recent development of chemotherapeutic agents, the prognosis of colorectal cancer (CRC) patients with peritoneal dissemination (PD) remains poor. The tumor immune microenvironment (TIME) has drawn attention as a key contributing factor of tumor progression. Of TIME components, myeloid-derived suppressor cells (MDSCs) are considered to play a responsible role in the immunosuppressive characteristics of the TIME. MDSCs are classified into two major subsets: Monocytic MDSCs (M-MDSCs) and polymorphonuclear MDSCs (PMN-MDSCs). Therefore, we hypothesize that MDSCs would play important roles in the PD-relevant TIME and PD progression. To address this hypothesis, we established PD mouse models. As the PD nodules consisted scarcely of immune cells, we focused on the peritoneal cavity, but not PD nodule, to evaluate the PD-relevant TIME. As a result, intraperitoneal PMN-MDSCs were found to be substantially increased in association with PD progression. Based on these results, we phenotypically and functionally verified the usefulness of CD244 for identifying PMN-MDSCs. In addition, the concentrations of interleukin (IL)-6 and granulocyte-colony stimulating factor (G-CSF) were significantly increased in the peritoneal cavity, both of which were produced by the tumors and thought to contribute to the increases in the PMN-MDSCs. In vivo depletion of the PMN-MDSCs by anti-Ly6G monoclonal antibody (mAb) significantly inhibited the PD progression and reverted CD4⁺ and CD8⁺ T cells in the peritoneal cavity and the peripheral blood. Collectively, these results suggest that the targeted therapy for PMN-MDSCs would provide not only new therapeutic value but also a novel strategy to synergize with T-cell-based immunotherapy for CRC-derived PD.