Tumor hypoxia enhances Non-Small Cell Lung Cancer metastasis by selectively promoting macrophage M2 polarization through the activation of ERK signaling

Pre-metastatic niche: formation, characteristics and therapeutic implication

Distant metastasis is a primary cause of mortality and contributes to poor surgical outcomes in cancer patients. Before the development of organ-specific metastasis, the formation of a pre-metastatic niche is pivotal in promoting the spread of cancer cells. This review delves into the intricate landscape of the pre-metastatic niche, focusing on the roles of tumor-derived secreted factors, extracellular vesicles, and circulating tumor cells in shaping the metastatic niche. The discussion encompasses cellular elements such as macrophages, neutrophils, bone marrow-derived suppressive cells, and T/B cells, in addition to molecular factors like secreted substances from tumors and extracellular vesicles, within the framework of pre-metastatic niche formation. Insights into the temporal mechanisms of pre-metastatic niche formation such as epithelial-mesenchymal transition, immunosuppression, extracellular matrix remodeling, metabolic reprogramming, vascular permeability and angiogenesis are provided. Furthermore, the landscape of pre-metastatic niche in different metastatic organs like lymph nodes, lungs, liver, brain, and bones is elucidated. Therapeutic approaches targeting the cellular and molecular components of pre-metastatic niche, as well as interventions targeting signaling pathways such as the TGF-β, VEGF, and MET pathways, are highlighted. This review aims to enhance our understanding of pre-metastatic niche dynamics and provide insights for developing effective therapeutic strategies to combat tumor metastasis.

The emerging role of lactate in tumor microenvironment and its clinical relevance

In recent years, the significant impact of lactate in the tumor microenvironment has been greatly documented. Acting not only as an energy substance in tumor metabolism, lactate is also an imperative signaling molecule. It plays key roles in metabolic remodeling, protein lactylation, immunosuppression, drug resistance, epigenetics and tumor metastasis, which has a tight relation with cancer patients' poor prognosis. This review illustrates the roles lactate plays in different aspects of tumor progression and drug resistance. From the comprehensive effects that lactate has on tumor metabolism and tumor immunity, the therapeutic targets related to it are expected to bring new hope for cancer therapy.

Macrophage colony-stimulating factor and its role in the tumor microenvironment: novel therapeutic avenues and mechanistic insights

The tumor microenvironment is a complex ecosystem where various cellular and molecular interactions shape the course of cancer progression. Macrophage colony-stimulating factor (M-CSF) plays a pivotal role in this context. This study delves into the biological properties and functions of M-CSF in regulating tumor-associated macrophages (TAMs) and its role in modulating host immune responses. Through the specific binding to its receptor colony-stimulating factor 1 receptor (CSF-1R), M-CSF orchestrates a cascade of downstream signaling pathways to modulate macrophage activation, polarization, and proliferation. Furthermore, M-CSF extends its influence to other immune cell populations, including dendritic cells. Notably, the heightened expression of M-CSF within the tumor microenvironment is often associated with dismal patient prognoses. Therefore, a comprehensive investigation into the roles of M-CSF in tumor growth advances our comprehension of tumor development mechanisms and unveils promising novel strategies and approaches for cancer treatment.

The Effect of Salvianolic Acid A on Tumor-Associated Macrophage Polarization and Its Mechanisms in the Tumor Microenvironment of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, with a high degree of malignancy and poor prognosis. Tumor-associated macrophages (TAMs) have been identified as significant contributors to the growth and metastasis of TNBC through the secretion of various growth factors and chemokines. Salvianolic acid A (SAA) has been shown to have anti-cancer activities. However, the potential activity of SAA on re-polarized TAMs remains unclear. As there is a correlation between the TAMs and TNBC, this study investigates the effect of SAA on TAMs in the TNBC microenvironment. For that purpose, M2 TAM polarization was induced by two kinds of TNBC-conditioned medium (TNBC-TCM) in the absence or presence of SAA. The gene and protein expression of TAM markers were analyzed by qPCR, FCM, IF, ELISA, and Western blot. The protein expression levels of ERK and p-ERK in M2-like TAMs were analyzed by Western blot. The migration and invasion properties of M2-like TAMs were analyzed by Transwell assays. Here, we demonstrated that SAA increased the expression levels of CD86, IL-1β, and iNOS in M2-like TAMs and, conversely, decreased the expression levels of Arg-1 and CD206. Moreover, SAA inhibited the migration and invasion properties of M2-like TAMs effectively and decreased the protein expression of TGF-β1 and p-ERK in a concentration-dependent manner, as well as TGF-β1 gene expression and secretion. Our current findings for the first time demonstrated that SAA inhibits macrophage polarization to M2-like TAMs by inhibiting the ERK pathway and promotes M2-like TAM re-polarization to the M1 TAMs, which may exert its anti-tumor effect by regulating M1/M2 TAM polarization. These findings highlight SAA as a potential regulator of M2 TAMs and the possibility of utilizing SAA to reprogram M2 TAMs offers promising insights for the clinical management of TNBC.

Boosting immune responses in lung tumor immune microenvironment: A comprehensive review of strategies and adjuvants

The immune system has a substantial impact on the growth and expansion of lung malignancies. Immune cells are encompassed by a stroma comprising an extracellular matrix (ECM) and different cells like stromal cells, which are known as the tumor immune microenvironment (TIME). TME is marked by the presence of immunosuppressive factors, which inhibit the function of immune cells and expand tumor growth. In recent years, numerous strategies and adjuvants have been developed to extend immune responses in the TIME, to improve the efficacy of immunotherapy. In this comprehensive review, we outline the present knowledge of immune evasion mechanisms in lung TIME, explain the biology of immune cells and diverse effectors on these components, and discuss various approaches for overcoming suppressive barriers. We highlight the potential of novel adjuvants, including toll-like receptor (TLR) agonists, cytokines, phytochemicals, nanocarriers, and oncolytic viruses, for enhancing immune responses in the TME. Ultimately, we provide a summary of ongoing clinical trials investigating these strategies and adjuvants in lung cancer patients. This review also provides a broad overview of the current state-of-the-art in boosting immune responses in the TIME and highlights the potential of these approaches for improving outcomes in lung cancer patients.

IL6-STAT3-C/EBPβ-IL6 positive feedback loop in tumor-associated macrophages promotes the EMT and metastasis of lung adenocarcinoma

BACKGROUND

Lung cancer is one of the most common tumors in the world, and metastasis is one of the major causes of tumor-related death in lung cancer patients. Tumor-associated macrophages (TAMs) are a major component of the tumor microenvironment (TME) and are frequently associated with tumor metastasis in human cancers. However, the regulatory mechanisms of TAMs in lung cancer metastasis remain unclear.

METHODS

Single-cell sequencing analysis of lung cancer and normal tissues from public databases and from 14 patients who underwent surgery at Zhongshan Hospital was performed. In vitro co-culture experiments were performed to evaluate the effects of TAMs on lung cancer migration and invasion. Changes in the expression of IL-6, STAT3, C/EBPΒ, and EMT pathway were verified using RT-qPCR, western blotting, and immunofluorescence. Dual luciferase reporter assays and ChIP were used to reveal potential regulatory sites on the transcription factor sets. In addition, the effects of TAMs on lung cancer progression and metastasis were confirmed by in vivo models.

RESULTS

TAM infiltration is associated with tumor progression and poor prognosis. IL-6 secreted by TAMs can activate the JAK2/STAT3 pathway through autocrine secretion, and STAT3 acts as a transcription factor to activate the expression of C/EBPβ, which further promotes the transcription and expression of IL-6, forming positive feedback loops for IL6-STAT3-C/EBPβ-IL6 in TAMs. IL-6 secreted by TAMs promotes lung cancer progression and metastasis in vivo and in vitro by activating the EMT pathway, which can be attenuated by the use of JAK2/STAT3 pathway inhibitors or IL-6 monoclonal antibodies.

CONCLUSIONS

Our data suggest that TAMs promote IL-6 expression by forming an IL6-STAT3-C/EBPβ-IL6 positive feedback loop. Released IL-6 can induce the EMT pathway in lung cancer to enhance migration, invasion, and metastasis. The use of IL-6-neutralizing antibody can partially counteract the promotion of LUAD by TAMs. A novel mechanism of macrophage-promoted tumor progression was revealed, and the IL6-STAT3-C/EBPβ-IL6 signaling cascade may be a potential therapeutic target against lung cancer.

CAMSAP2 enhances lung cancer cell metastasis by mediating RASAL2 degradation

AIMS

Cancer metastasis significantly contributes to mortality in lung cancer patients. Calmodulin-regulated spectrin-associated protein family member 2 (CAMSAP2) plays a significant role in cancer cell migration; however, its role in lung cancer metastasis and the underlying mechanism remain largely unknown. The present study aimed to investigate the impact of CAMSAP2 on lung cancer.

MAIN METHODS

The clinical relevance of CAMSAP2 in lung cancer patients was assessed using public database. RNA interference experiments were conducted to investigate role of CAMSAP2 in cell migration through transwell and wound healing assays. Molecular mechanisms were explored by identifying the possible interacting partners and pathways using the BioGRID and KEGG pathway analyses. The impact of CAMSAP2 on Ras protein activator-like 2 (RASAL2)-mediated lung cancer metastasis was investigated through biochemical assays. Additionally, in vivo experimentation using a murine tail vein metastasis model was performed to comprehend CAMSAP2's influence on metastasis.

KEY FINDINGS

A high expression level of CAMSAP2 was associated with poor overall survival in lung cancer patients and it positively correlated with cell migration in non-small cell lung cancer (NSCLC) cell lines. Knockdown of CAMSAP2 inhibited lung cancer cell motility in vitro and metastasis in vivo. Proteomic and biochemical analyses revealed the interaction between CAMSAP2 and RASAL2, which facilitates the degradation of RASAL2 through the ubiquitin-proteasome system. These degradation processes resulted in the activation of the extracellular signal-regulated kinase (ERK) signaling pathway, thereby promoting lung cancer metastasis. Collectively, the results of this study suggest that CAMSAP2 is a crucial regulator of cancer cell migration and metastasis and a promising therapeutic target for lung cancer.

Next-Cell Hypothesis: Mechanism of Obesity-Associated Carcinogenesis

Higher body fat content is related to a higher risk of mortality, and obesity-related cancer represents approximately 40% of all cancer patients diagnosed each year. Furthermore, epigenetic mechanisms are involved in cellular metabolic memory and can determine one's predisposition to being overweight. Low-grade chronic inflammation, a well-established characteristic of obesity, is a central component of tumor development and progression. Cancer-associated adipocytes (CAA), which enhance inflammation- and metastasis-related gene sets within the cancer microenvironment, have pro-tumoral effects. Adipose tissue is a major source of the exosomal micro ribonucleic acids (miRNAs), which modulate pathways involved in the development of obesity and obesity-related comorbidities. Owing to their composition of cargo, exosomes can activate receptors at the target cell or transfer molecules to the target cells and thereby change the phenotype of these cells. Exosomes that are released into the extracellular environment are internalized with their cargo by neighboring cells. The tumor-secreted exosomes promote organ-specific metastasis of tumor cells that normally lack the capacity to metastasize to a specific organ. Therefore, the communication between neighboring cells via exosomes is defined as the "next-cell hypothesis." The reciprocal interaction between the adipocyte and tumor cell is realized through the adipocyte-derived exosomal miRNAs and tumor cell-derived oncogenic miRNAs. The cargo molecules of adipocyte-derived exosomes are important messengers for intercellular communication involved in metabolic responses and have very specific signatures that direct the metabolic activity of target cells. RNA-induced silencing regulates gene expression through various mechanisms. Destabilization of DICER enzyme, which catalyzes the conversion of primary miRNA (pri-miRNA) to precursor miRNA (pre-miRNA), is an important checkpoint in cancer development and progression. Interestingly, adipose tissue in obesity and tumors share similar pathogenic features, and the local hypoxia progress in both. While hypoxia in obesity leads to the adipocyte dysfunction and metabolic abnormalities, in obesity-related cancer cases, it is associated with worsened prognosis, increased metastatic potential, and resistance to chemotherapy. Notch-interleukin-1 (IL-1)-Leptin crosstalk outcome is referred to as "NILCO effect." In this chapter, obesity-related cancer development is discussed in the context of "next-cell hypothesis," miRNA biogenesis, and "NILCO effect."

The role of tumor-associated macrophages in lung cancer: From mechanism to small molecule therapy

Tumor-associated macrophages (TAMs) are the main component of tumor-infiltrating immune cells in the lung tumor microenvironment. TAMs recruited to the lung cancer can create a suitable microenvironment for the growth and metastasis of lung cancer by secreting tumor promoting factors and interfering with the function of T cells. Currently, numerous studies have reported that small molecular drugs affect lung cancer progression by selectively targeting TAMs. The main ways include blocking the recruitment of monocytes or eliminating existing TAMs in tumor tissue, reprogramming TAMs into pro-inflammatory M1 macrophages or inhibiting M2 polarization of macrophages, interrupting the interaction between tumor cells and macrophages, and modulating immune function. Signaling pathways or cytokines such as CCL8, CCL2/CCR2, CSF-1/CSF-1R, STAT3, STAT6, MMPs, Caspase-8, AMPK α1, TLR3, CD47/SIRPα, have been reported to be involved in this process. Based on summarizing the role and mechanisms of TAMs in lung cancer progression, this paper particularly focuses on systematically reviewing the effects and mechanisms of small molecule drugs on lung cancer TAMs, and classified the small molecular drugs according to the way they affect TAMs. The study aims to provide new perspectives and potential therapeutic drugs for targeted macrophages treatment in lung cancer, which is of great significance and will provide more options for immunotherapy of lung cancer.

The Multifunction Role of Tumor-Associated Mesenchymal Stem Cells and Their Interaction with Immune Cells in Breast Cancer

Mesenchymal stem cells (MSCs) are a heterogeneous group of progenitor cells that play a multifunctional role including tissue regeneration, self-renewal properties, and differentiate into cells of mesodermal lineage such as adipocytes, osteoblasts, and chondrocytes. MSCs come into contact with tumor microenvironment (TME) and differentiate into tumor-associated MSCs (TA-MSCs). Various substances such as chemokines, cytokines, growth factors, and others are released by tumor cells to recruit MSCs. TA-MSCs induced epithelial-mesenchymal transition (EMT) program which mediates tumor growth progression, migration, and invasion. Role of MSCs in the tumor progression, stemness, malignancy, and treatment resistance in the breast cancer TME. Immunomodulation by MSCs is mediated by a combination of cell contact-dependent mechanisms and soluble substances. Monocytes/macrophages, dendritic cells, T cells, B cells, and NK cells all show signs of MSCs' immunomodulatory capability. In a complicated interplay initiated by MSCs, anti-inflammatory monocytes/macrophages and regulatory T cells (Tregs) play a key role, as they unveil their full immunomodulatory potential. MSC- secreted cytokines are commonly blamed for the interaction between MSCs, monocytes, and Tregs. Here, we review the current knowledge of cellular and molecular mechanisms involved in MSC-mediated immunomodulation and focus on the role MSCs play in breast cancer progression and its TME.Abbreviation MSC: Mesenchymal Stem Cells; TME: Tumor Microenvironment; TAMS; Tumour-associated Macrophages; ECM: Extracellular matrix; CAFs: Cancer-associated Fibroblasts; CFUs: Colony-forming unit Fibroblasts; Tregs: T regulatory cells; Bregs; Regulatory B cells; IFN-γ: Interferon-gamma; TNF-α: Tumour Necrosis Factor-alpha; IL: Interleukin; TGF-β: transforming growth factorβ; PGE2: Prostaglandin E2; CXCR: Chemokine Receptor; Blimp-1; B lymphocyte-induced maturation protein-1; CCL: Chemokine motif ligand; EMT: Epithelial-mesenchymal transition.

Scutellarin Acts via MAPKs Pathway to Promote M2 Polarization of Microglial Cells

Scutellarin, an herbal agent, is known to possess anti-oxidant and anti-inflammatory properties. In activated microglia, it has been reported that this is achieved through acting on the MAPKs, a key pathway that regulates microglia activation. This study sought to determine if scutellarin would affect the commonly described microglia phenotypes, namely, M1 and M2, thought to contribute to pro- and anti-inflammatory roles, respectively. This is in consideration of its potential effect on the polarization of microglia phenotypes that are featured prominently in cerebral ischemia. For this purpose, we have used an experimentally induced cerebral ischemia rat model and LPS-stimulated BV-2 cell model. Thus, by Western blot and immunofluorescence, we show here a noticeable increase in expression of M2 microglia markers, namely, CD206, Arg1, YM1/2, IL-4 and IL-10 in activated microglia both in vivo and in vitro. Besides, we have confirmed that Scutellarin upregulated expression of Arg1, IL-10 and IL-4 in medium supernatants of BV-2 microglia. Remarkably, scutellarin treatment markedly augmented the increased expression of the respective markers in activated microglia. It is therefore suggested scutellarin can exert the polarization of activated microglia from M1 to M2 phenotype. Because M1 microglia are commonly known to be proinflammatory, while M2 microglia are anti-inflammatory and neuroprotective effect, it stands to reason therefore that with the increase of M2 microglia which became predominant by scutellarin, the local inflammatory response is ameliorated. More importantly, we have found that scutellarin promotes the M2 polarization through inhibiting the JNK and p38 signaling pathways, and concomitantly augmenting the ERK1/2 signaling pathway. This lends its strong support from observations in LPS activated BV-2 microglia treated with p38 and JNK inhibitors in which expression of M2 markers was increased; on the other hand, in cells subjected to ERK1/2 inhibitor treatment, the expression was suppressed. In light of the above, MAPKs pathway is deemed to be a potential therapeutic target of scutellarin in mitigating microglia mediated neuroinflammation in activated microglia.

Targeting the NF-κB pathway enhances responsiveness of mammary tumors to JAK inhibitors

Interactions between tumor cells and the tumor microenvironment are critical for tumor growth, progression, and response to therapy. Effective targeting of oncogenic signaling pathways in tumors requires an understanding of how these therapies impact both tumor cells and cells within the tumor microenvironment. One such pathway is the janus kinase (JAK)/signal transducer and activator or transcription (STAT) pathway, which is activated in both breast cancer cells and in tumor associated macrophages. This study demonstrates that exposure of macrophages to JAK inhibitors leads to activation of NF-κB signaling, which results in increased expression of genes known to be associated with therapeutic resistance. Furthermore, inhibition of the NF-κB pathway improves the ability of ruxolitinib to reduce mammary tumor growth in vivo. Thus, the impact of the tumor microenvironment is an important consideration in studying breast cancer and understanding such mechanisms of resistance is critical to development of effective targeted therapies.

Macrophage Polarization: An Important Candidate Regulator for Lung Diseases

Macrophages are crucial components of the immune system and play a critical role in the initial defense against pathogens. They are highly heterogeneous and plastic and can be polarized into classically activated macrophages (M1) or selectively activated macrophages (M2) in response to local microenvironments. Macrophage polarization involves the regulation of multiple signaling pathways and transcription factors. Here, we focused on the origin of macrophages, the phenotype and polarization of macrophages, as well as the signaling pathways associated with macrophage polarization. We also highlighted the role of macrophage polarization in lung diseases. We intend to enhance the understanding of the functions and immunomodulatory features of macrophages. Based on our review, we believe that targeting macrophage phenotypes is a viable and promising strategy for treating lung diseases.

Macrophages Phenotype Regulated by IL-6 Are Associated with the Prognosis of Platinum-Resistant Serous Ovarian Cancer: Integrated Analysis of Clinical Trial and Omics

Background

The treatment of platinum-resistant recurrent ovarian cancer (PROC) is a clinical challenge and a hot topic. Tumor microenvironment (TME) as a key factor promoting ovarian cancer progression. Macrophage is a component of TME, and it has been reported that macrophage phenotype is related to the development of PROC. However, the mechanism underlying macrophage polarization and whether macrophage phenotype can be used as a prognostic indicator of PROC remains unclear.

Methods

We used ESTIMATE to calculate the number of immune and stromal components in high-grade serous ovarian cancer (HGSOC) cases from The Cancer Genome Atlas database. The differential expression genes (DEGs) were analyzed via protein-protein interaction network, Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) analysis to reveal major pathways of DEGs. CD80 was selected for survival analysis. IL-6 was selected for gene set enrichment analysis (GSEA). A subsequent cohort study was performed to confirm the correlation of IL-6 expression with macrophage phenotype in peripheral blood and to explore the clinical utility of macrophage phenotype for the prognosis of PROC patients.

Results

A total of 993 intersecting genes were identified as candidates for further survival analysis. Further analysis revealed that CD80 expression was positively correlated with the survival of HGSOC patients. The results of GO and KEGG analysis suggested that macrophage polarization could be regulated via chemokine pathway and cytokine-cytokine receptor interaction. GSEA showed that the genes were mainly enriched in IL-6-STAT-3. Correlation analysis for the proportion of tumor infiltration macrophages revealed that M2 was correlated with IL-6. The results of a cohort study demonstrated that the regulation of macrophage phenotype by IL-6 is bidirectional. The high M1% was a protective factor for progression-free survival.

Conclusion

Thus, the macrophage phenotype is a prognostic indicator in PROC patients, possibly via a hyperactive IL-6-related pathway, providing an additional clue for the therapeutic intervention of PROC.

Metabolite activation of tumorigenic signaling pathways in the tumor microenvironment

The role of metabolites exchanged in the tumor microenvironment is largely thought of as fuels to drive the increased biosynthetic and bioenergetic demands of growing tumors. However, this view is shifting as metabolites are increasingly shown to function as signaling molecules that directly regulate oncogenic pathways. Combined with our growing understanding of the essential role of stromal cells, this shift has led to increased interest in how the collective and interconnected metabolome of the tumor microenvironment can drive malignant transformation, epithelial-to-mesenchymal transition, drug resistance, immune evasion, and metastasis. In this review, we discuss how metabolite exchange between tumors and various cell types in the tumor microenvironment—such as fibroblasts, adipocytes, and immune cells—can activate signaling pathways that drive cancer progression.

Gastric cancer-derived exosomal miR-519a-3p promotes liver metastasis by inducing intrahepatic M2-like macrophage-mediated angiogenesis

Background

Liver metastasis (LM) is a major obstacle to the prognosis of gastric cancer (GC) patients, but the molecular mechanism underlying gastric cancer liver metastasis (GC-LM) remains unknown. Exosomes have been identified as an important mediator of communication between tumor cells and the microenvironment. Therefore, we sought to investigate the effects of primary GC cells on the liver microenvironment and the role of exosomal microRNAs (exo-miRNA) in GC-LM.

Methods

Sequential differential centrifugation, transmission electron microscopy and NanoSight analysis were used to extract and characterize exosomes. MicroRNA sequencing in GC-derived exosomes and mRNA sequencing in PMA-treated THP-1 cells were used to identify differentially expressed miRNAs in exosomes and the functional targets of exosomal miR-519a-3p (exo-miR-519a-3p) in macrophages, respectively. Tracing and internalization of exosomes and transfer of exo-miR-519a-3p were observed by immunofluorescence. Tubule formation assays, aortic ring assays, and exosome-educated GC-LM model were used to investigate the roles of GC-derived exosomes and exo-miR-519a-3p in angiogenesis and GC-LM. Luciferase reporter assay, qRT-PCR, Western blot, ELISA, flow cytometry and immunofluorescence were used to investigate the regulatory mechanism of exo-miR-519a-3p at GC-LM.

Results

The expression level of miR-519a-3p in serum exosomes was significantly higher in GC-LM patients than in patients without LM, and high expression of exo-miR-519a-3p indicates a worse prognosis. GC-derived exosomes are mainly accumulated in the liver and internalized by intrahepatic macrophages. Mechanistically, exo-miR-519a-3p activates the MAPK/ERK pathway by targeting DUSP2, thereby causing M2-like polarization of macrophages. M2-like polarized macrophages accelerate GC-LM by inducing angiogenesis and promoting intrahepatic premetastatic niche formation.

Conclusions

Our results indicate that exo-miR-519a-3p plays a critical role in mediating crosstalk between primary GC cells and intrahepatic macrophages and is a potential therapeutic target for GC-LM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02499-8.

Development and validation of a hypoxia-associated signature for lung adenocarcinoma

Hypoxia is common in non-small cell lung cancer (NSCLC) and an attractive therapeutic target. As hypoxia-targeting treatments are effective in patients with the most hypoxic tumours, we aimed to develop a lung adenocarcinoma (LUAD) hypoxia-related gene expression signature. RNAseq was used to identify genes significantly differentially expressed under hypoxia (1% O2) in four LUAD cell lines. Identified genes were used for unsupervised clustering of a TCGA-LUAD training dataset (n = 252) and in a machine learning approach to build a hypoxia-related signature. Thirty-five genes were upregulated in common in three of the four lines and reduced in the training cohort to a 28-gene signature. The signature was prognostic in the TCGA training (HR 2.12, 95% CI 1.34-3.37, p = 0.0011) and test (n = 250; HR 2.13, 95% CI 1.32-3.45, p = 0.0016) datasets. The signature was prognostic for overall survival in a meta-analysis of nine other datasets (n = 1257; HR 2.08, 95% CI 1.60-2.70, p < 0.0001). The 28-gene LUAD hypoxia related signature can be taken forward for further validation using a suitable gene expression platform.

[Advances in the Study of Tumor-associated Macrophages in Lung Cancer]

肺癌是全球发病率和死亡率最高的恶性肿瘤之一。因此对于肺癌治疗手段的研究也在不断深入，目前临床上主要有全身化疗、针对驱动基因阳性的靶向治疗、免疫检查点抑制剂的应用、抗肿瘤血管生成治疗以及上述不同治疗方法的联合等，这些方案的使用明显改善了大多数肺癌患者的预后，但晚期患者预后仍然不尽如人意。近年来，与免疫相关的肿瘤微环境（tumor microenvironment, TME）的研究越来越受到重视。TME由免疫细胞、成纤维细胞、血管内皮细胞等细胞成分及相关的细胞因子等组成，是肿瘤细胞赖以生存、发展的基础。而肿瘤相关巨噬细胞（tumor-associated macrophages, TAMs）是TME重要的免疫细胞，指浸润于肿瘤组织中的巨噬细胞，可促进肿瘤细胞增殖，诱导肿瘤免疫耐受，刺激肿瘤血管生成，增加肿瘤细胞的侵袭及转移能力。因此，靶向TAMs已经成为肺癌免疫治疗的热点。本文就TAMs来源、表型及其在肺癌中的作用机制以及在未来治疗中的靶点进行综述，为肺癌最优化治疗提供参考。

Cross Talk Between Macrophages and Cancer Cells in the Bone Metastatic Environment

The skeleton is a common site for cancer metastases with the bone microenvironment providing the appropriate conditions for cancer cell colonization. Once in bone, cancer cells effectively manipulate their microenvironment to support their growth and survival. Despite previous efforts to improve treatment modalities, skeletal metastases remain with poor prognoses. This warrants an improved understanding of the mechanisms leading to bone metastasis that will aid development of effective treatments. Macrophages in the tumor microenvironment are termed tumor associated macrophages (TAMs) and their crosstalk with cancer cells is critical in regulating tumorigenicity in multiple cancers. In bone metastases, this crosstalk is also being increasingly implicated but the specific signaling pathways remain incompletely understood. Here, we summarize the reported functions, interactions, and signaling of macrophages with cancer cells during the metastatic cascade to bone. Specifically, we review and discuss how these specific interactions impact macrophages and their profiles to promote tumor development. We also discuss the potential of targeting this crosstalk to inhibit disease progression. Finally, we identify the remaining knowledge gaps that will need to be addressed in order to fully consider therapeutic targeting to improve clinical outcomes in cancer patients.

Effects of strontium-incorporated micro/nano rough titanium surfaces on osseointegration via modulating polarization of macrophages

Macrophages perform multiple functions in both inflammation and wound healing, and are one of the fore front cells during implant osseointegration that influence subsequent process. Essential trace element modification may effectively modulate titanium implant surface biological properties. In this work, strontium (Sr) incorporated micro/nano rough titanium surfaces (Sr-SLA) was fabricated by hydrothermal treatment, and immunoreaction of macrophages was further investigated. In vitro results revealed that Sr doping inhibited inflammatory response of macrophages, further attenuated the inhibitory effect on following bone marrow derived cells (BMSCs) osteogenic differentiation. The regulation of macrophages by Sr-SLA likely involved ERK signaling pathway. Consistently, the in vivo study showed that compared with titanium surface sand-blasted with large grit and double acid-etched (SLA) implants, Sr-SLA implants could enhance new bone formation accompanied with more alternatively activated M2 macrophages infiltration and less classically activated M1 macrophages infiltration. These results reveal the immunomodulatory ability of Sr-SLA of adjusting the functional status of macrophages through inhibiting M1 polarization while promoting M2 polarization.

The Prognostic Value of CD206 in Solid Malignancies: A Systematic Review and Meta-Analysis

Simple Summary

The role of innate immune cells in the tumor microenvironment (TME), more specifically the presence of the tumor associated macrophages (TAMs), is becoming more important in the prognosis and treatment of patients diagnosed with malignancies. The aim of this systematic review and meta-analysis was to assess the potential prognostic value of CD206-expressing TAMs, a subclass of macrophages, which were previously proposed to negatively impact the patient’s prognosis. We identified 27 manuscripts describing the role of CD206 in patient prognosis for 14 different tumor types. Despite a large heterogeneity in the results, we identified a significantly worse overall and disease-free survival for patients with increased CD206-expressing TAMs in the TME. The use of CD206-expressing TAMs could therefore be used as a prognostic marker in patients diagnosed with solid malignancies.

Abstract

An increased presence of CD206-expressing tumor associated macrophages in solid cancers was proposed to be associated with worse outcomes in multiple types of malignancies, but contradictory results are published. We performed a reproducible systematic review and meta-analysis to provide increased evidence to confirm or reject this hypothesis following the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. The Embase, Web of Science, and MEDLINE-databases were systematically searched for eligible manuscripts. A total of 27 papers studying the prognostic impact of CD206 in 14 different tumor types were identified. Meta-analyses showed a significant impact on the overall survival (OS) and disease-free survival (DFS). While no significant differences were revealed in progression-free survival (PFS) and disease-specific survival (DSS), a shift towards negative survival was correlated with increased CD206-expresion. As a result of the different tumor types, large heterogeneity was present between the different tumor types. Subgroup analysis of hepatocellular carcinoma and gastric cancers revealed no heterogeneity, associated with a significant negative impact on OS in both groups. The current systematic review displays the increased presence CD206-expressing macrophages as a significant negative prognostic biomarker for both OS and DFS in patients diagnosed with solid cancers. Because a heterogenous group of tumor types was included in the meta-analysis, the results cannot be generalized. These results can, however, be used to further lead follow-up research to validate the specific prognostic value of CD206 in individual tumor types and therapeutic approaches.

Inhibiting NF-κB Signaling Activation Reduces Retinal Neovascularization by Promoting a Polarization Shift in Macrophages

Purpose

Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling is involved in regulating tumor angiogenesis and metastasis; however, the exact mechanism of action in retinal neovascularization (RNV) remains unclear. The purpose of this study was to determine the role and underlying mechanism of NF-κB in regulating RNV in retinal neovascularization mice.

Methods

Expression levels of NF-κB signaling were detected by immunofluorescence staining and western blotting in retinas of oxygen-induced retinopathy (OIR) mice. OIR mice were treated with either pyrrolidinedithiocarbamate (PDTC), a NF-κB signaling inhibitor, or PBS, and retinal flat-mounts were performed to quantify the area of RNV and the recruitment of retinal macrophages by immunofluorescence staining. Macrophage polarization detected by flow cytometric analysis and the expression of macrophage polarization-associated genes were evaluated by immunofluorescence staining, quantitative RT-PCR, and western blotting.

Results

Expression levels of phosphorylated IκBα (p-IκBα) and p-p65 increased in OIR mice. Inhibiting NF-κB signaling activation by PDTC significantly reduced RNV. After treatment with PDTC, a reduction in the quantity of macrophages was observed: M1 polarized macrophages decreased, and M2 polarized macrophages increased; the expression of M1 macrophage-associated cytokines decreased and M2 macrophage-associated cytokines increased in the retinas of OIR mice.

Conclusions

Blocking activation of NF-κB signaling reduces RNV by promoting polarization of M1 macrophages to M2 macrophages in OIR mice.

Cyclic Hypoxia: An Update on Its Characteristics, Methods to Measure It and Biological Implications in Cancer

Regions of hypoxia occur in most if not all solid cancers. Although the presence of tumor hypoxia is a common occurrence, the levels of hypoxia and proportion of the tumor that are hypoxic vary significantly. Importantly, even within tumors, oxygen levels fluctuate due to changes in red blood cell flux, vascular remodeling and thermoregulation. Together, this leads to cyclic or intermittent hypoxia. Tumor hypoxia predicts for poor patient outcome, in part due to increased resistance to all standard therapies. However, it is less clear how cyclic hypoxia impacts therapy response. Here, we discuss the causes of cyclic hypoxia and, importantly, which imaging modalities are best suited to detecting cyclic vs. chronic hypoxia. In addition, we provide a comparison of the biological response to chronic and cyclic hypoxia, including how the levels of reactive oxygen species and HIF-1 are likely impacted. Together, we highlight the importance of remembering that tumor hypoxia is not a static condition and that the fluctuations in oxygen levels have significant biological consequences.

Serum and Glucocorticoid-Inducible Kinase 1 (SGK1) in NSCLC Therapy

Non-small cell lung cancer (NSCLC) remains the most prevalent and one of the deadliest cancers worldwide. Despite recent success, there is still an urgent need for new therapeutic strategies. It is also becoming increasingly evident that combinatorial approaches are more effective than single modality treatments. This review proposes that the serum and glucocorticoid-inducible kinase 1 (SGK1) may represent an attractive target for therapy of NSCLC. Although ubiquitously expressed, SGK1 deletion in mice causes only mild defects of ion physiology. The frequent overexpression of SGK1 in tumors is likely stress-induced and provides a therapeutic window to spare normal tissues. SGK1 appears to promote oncogenic signaling aimed at preserving the survival and fitness of cancer cells. Most importantly, recent investigations have revealed the ability of SGK1 to skew immune-cell differentiation toward pro-tumorigenic phenotypes. Future studies are needed to fully evaluate the potential of SGK1 as a therapeutic target in combinatorial treatments of NSCLC. However, based on what is currently known, SGK1 inactivation can result in anti-oncogenic effects both on tumor cells and on the immune microenvironment. A first generation of small molecules to inactivate SGK1 has already been already produced.

The Crosstalk Between Tumor-Associated Macrophages (TAMs) and Tumor Cells and the Corresponding Targeted Therapy

Tumor microenvironment (TME) is composed of tumor cells and surrounding non-tumor stromal cells, mainly including tumor associated macrophages (TAMs), endothelial cells, and carcinoma-associated fibroblasts (CAFs). The TAMs are the major components of non-tumor stromal cells, and play an important role in promoting the occurrence and development of tumors. Macrophages originate from bone marrow hematopoietic stem cells and embryonic yolk sacs. There is close crosstalk between TAMs and tumor cells. With the occurrence of tumors, tumor cells secrete various chemokines to recruit monocytes to infiltrate tumor tissues and further promote their M2-type polarization. Importantly, M2-like TAMs can in turn accelerate tumor growth, promote tumor cell invasion and metastasis, and inhibit immune killing to promote tumor progression. Therefore, targeting TAMs in tumor tissues has become one of the principal strategies in current tumor immunotherapy. Current treatment strategies focus on reducing macrophage infiltration in tumor tissues and reprogramming TAMs to M1-like to kill tumors. Although these treatments have had some success, their effects are still limited. This paper mainly summarized the recruitment and polarization of macrophages by tumors, the support of TAMs for the growth of tumors, and the research progress of TAMs targeting tumors, to provide new treatment strategies for tumor immunotherapy.

Tumor‑associated macrophages in lung cancer: Friend or foe? (Review)

Typically, tumor-associated macrophages (TAMs), an abundant population of leukocytes in lung cancer, are affected by tumor microenvironment (TME) and shift towards either a pro-tumor (M2-like) or an anti-tumor phenotype (M1-like). M2-polarized macrophages, are one of the primary tumor-infiltrating immune cells and were reported to be associated with the promotion of cancer cell growth, invasion, metastasis, and angiogenesis. TAMs are considered a potential target for adjuvant anticancer therapies, and recent therapeutic approaches targeting the M2 polarization of TAMs have shown encouraging results. The present review discusses recent developments in the role of TAMs in cancer, in particular TAMs functions, clinical implication and prospective therapeutic strategies in lung cancer.

Splenectomy enhances the Ly6Clow phenotype in hepatic macrophages by activating the ERK1/2 pathway during liver fibrosis

BACKGROUND AND AIM

Splenectomy has been reported to attenuate liver fibrosis. In addition, phenotype transitions of infiltrating macrophages, including Ly6Chigh and Ly6Clow, play an essential role in the liver fibrosis. However, whether the spleen can regulate the phenotype switch of macrophages and the underlying mechanism still remain unclear.

METHODS

Chronic liver fibrosis in mice was induced by intraperitoneal injection with carbon tetrachloride. Splenectomy or sham operation was performed with or without depletion of macrophages during liver fibrosis. Liver fibrosis and the proportion of Ly6Chigh and Ly6Clow macrophages were analyzed. Western blotting of ERK1/2 signals was performed in isolated macrophages to investigate the underlying mechanism of phenotype transition. RAW264.7 cells were stimulated by liver total cells conditioned medium with or without preincubation of SCH772984, the ERK1/2 inhibitor, and the phenotype switch of RAW264.7 cells was examined. In vivo, intraperitoneal injection of SCH772984 was performed on the splenectomy mice and the phenotype switch of liver infiltrating macrophages was tested.

RESULTS

Splenectomy alleviated the liver inflammation and fibrosis and also promoted the phenotypic switch of infiltrating macrophages to a Ly6Clow phenotype in fibrotic liver. The p-ERK1/2 expression was upregulated in macrophages at the same time. Furthermore, splenectomy increased the percentage of Ly6Clow macrophages and decreased the percentage of Ly6Chigh macrophages both in vivo and in vitro, which was reversed by SCH772984.

CONCLUSIONS

Splenectomy attenuates both the liver fibrosis and inflammation, and promotes the phenotype switch of infiltrating macrophages to an anti-inflammatory Ly6Clow phenotype by activating the ERK1/2 pathway during liver fibrosis.

Cationic Lipid-based Intracellular Delivery of Bacterial Effectors for Rewiring Malignant Cell Signaling

The abundance of bacterial effectors have inspired us to explore their potential in rewiring malignant cell signaling. Their incapability for entering cells, however, hinders such application. Herein we developed a cationic lipid-based high throughput library screening platform for effective intracellular delivery of bacterial effectors. As the misregulated MAPK signaling is a hallmark of many types of cancer, we turned to the Shigella effector OspF which irreversibly inactivates ERK, the terminal component of MAPK cascade. We created a function-based screening assay to obtain AMPA-O16B lipid nanoparticles for effective OspF intracellular delivery, which inhibited the malignant MAPK signaling and tumor growth in vitro and in vivo. Furthermore, the optimized lipid nanoparticle formulation can deliver OspF to modulate the immunosuppressive responses in macrophages. Our work is a general strategy to explore the therapeutic potentials of naturally evolved bacterial effectors.

Extracellular ubiquitin promotes hepatoma metastasis by mediating M2 macrophage polarization via the activation of the CXCR4/ERK signaling pathway

Background

Stored red blood cell (RBC) transfusion has been shown to enhance the risk of cancer recurrence. However, the underlying mechanism remains unknown. At our lab, we have demonstrated that the extracellular ubiquitin (eUb) released by aged RBCs could promote tumor metastasis in a melanoma mouse model. This study aimed to confirm the pro-tumor effect of eUb on hepatocellular carcinoma (HCC) and explore the related immunoregulatory mechanisms.

Methods

Forty HCC tissue specimens and the corresponding adjacent nontumor and normal liver tissues were collected. Two human hepatoma cell lines (MHCC-97H and HepG2.2.15), one murine hepatoma cell line (Hepa1-6), and one human monocyte cell line (THP-1) were adopted in this study. The coculture of hepatoma cells with macrophages was initiated with Transwell inserts. Cell migration in vitro was detected by Transwell and wound-healing assays, while in vivo tumor metastasis was measured by luciferase assay and H&E staining. Macrophage polarization was measured by flow cytometry, immunofluorescence, ELISA, qPCR, and Western blot. Protein expression was detected by Western blot, and immunoprecipitation was used to confirm the interaction between Ub and CXCR4 (CXC chemokine receptor type 4).

Results

Ub and CXCR4 were significantly upregulated in HCC tissues, and a positive correlation existed between them. In vitro, the migration of hepatoma cells was not affected by eUb directly, but their metastatic abilities were enhanced after coculture with the macrophages pretreated with eUb. Meanwhile, eUb promoted hepatoma cell metastasis in the lung in vivo and increased the ratio of M2 macrophages in the lung tissues and peripheral blood of tumor-bearing mice. Furthermore, the eUb-induced M2 macrophage polarization was related to the activation of the CXCR4/ERK (extracellular regulated protein kinase) signaling pathway.

Conclusions

Extracellular ubiquitin promoted hepatoma metastasis through M2 macrophage polarization via the activation of the CXCR4/ERK signaling pathway, indicating that a personalized transfusion strategy is needed for the treatment of HCC patients. Neutralizing Ub in stored RBC units could lessen the detrimental clinical outcomes induced by the transfusion of stored RBCs.

miR-495 and miR-5688 are down-regulated in non-small cell lung cancer under hypoxia to maintain interleukin-11 expression

Background

Hypoxia is a hallmark of cancer and is associated with poor prognosis. However, the molecular mechanism by which hypoxia promotes tumor progression remains unclear. MicroRNAs dysregulation has been shown to play a critical role in the tumor and tumor microenvironment. Here, we investigated the roles of miR‐495 and miR‐5688 in human non‐small cell lung cancer (NSCLC) and their underlying mechanism.

Methods

The expression levels of miR‐495 and miR‐5688 in human NSCLC tissue specimens were measured by quantitative real‐time polymerase chain reaction (qRT‐PCR). Deferoxamine (DFO) was used to determine whether the regulation of miR‐495 and miR‐5688 under hypoxia was dependent on hypoxia‐inducible factor 1‐alpha (HIF‐1α). Furthermore, the functions of miR‐495 and miR‐5688 in tumor progression were evaluated using colony formation, 3‐(4,5‐dimethylthiazol‐2‐yl)‐5‐(3‐carboxymethoxyphenyl)‐2‐(4‐sulfophenyl)‐2H‐tetrazolium (MTS), wound healing, transwell assays, and xenograft model. Two algorithms, PicTAR and Targetscan, were used to predict the target gene of these two miRNAs, and dual‐luciferase reporter assay was conducted to confirm the target. The unpaired two‐tailed t test, Pearson correlation analysis, and Fisher's exact probability test were performed for statistical analyses.

Results

Two miRNAs, miR‐495 and miR‐5688, were found to participate in NSCLC progression under hypoxia. They were down‐regulated in NSCLC tissues compared with normal tissues. We determined that hypoxia led to the down‐regulation of miR‐495 and miR‐5688 in NSCLC cells, which was independent of HIF‐1α and cellular metabolic energy. In addition, miR‐495 and miR‐5688 suppressed cell proliferation, migration, and invasion in vitro. The NSCLC xenograft model showed that miR‐495 and miR‐5688 inhibited tumor formation in vivo. Interestingly, we found that miR‐495 and miR‐5688 had the same target, interleukin‐11 (IL‐11). Recombinant human IL‐11 counteracted the effects of miR‐495 and miR‐5688 on NSCLC cells, suggesting that miR‐495 and miR‐5688 executed their tumor suppressive role by repressing IL‐11 expression.

Conclusion

We found that hypoxia down‐regulated the expression levels of miR‐495 and miR‐5688 in NSCLC to enhance IL‐11 expression and tumor progression, indicating that the miR‐495/miR‐5688/IL‐11 axis may serve as a therapeutic target and potential biomarker for NSCLC.

Trophoblast-derived IL-6 serves as an important factor for normal pregnancy by activating Stat3-mediated M2 macrophages polarization

Macrophages are major components of decidual microenvironment that play an important role in human implantation and placentation. Trophoblasts which migrate into the endometrium and interplay with decidual cells, have been reported to participate in the polarization of macrophages. However, the potential mechanisms of trophoblasts modulating M2 macrophages polarization still need further exploration. Herein, we used the co-cultured model to investigate the interaction between macrophages and trophoblasts. Our results illustrated that when co-cultured with trophoblasts, macrophages tended to polarize to M2-subtype, accompanied by increased expression of multiple M2 markers including CD206 and CCL18 mRNA expression and IL-10 and TGF-β protein level. Further experiments identified that trophoblast-derived IL-6, as the major contributor, promoted M2 macrophages polarization by activating Stat3 pathway. Moreover, activated M2 macrophages exerted a promoting role in the invasion and migration of trophoblasts in a feedback manner. Clinically, results from histology demonstrated that IL-6 expression in placental villous tissues was positive correlated with CD206-positive macrophage infiltration in decidua in normal pregnancy patients. Altogether, our findings indicate that trophoblasts induce M2 macrophages polarization via IL-6/Stat3 signal pathway, which in turn promote the invasion and migration of trophoblasts. These results provide insights into the crosstalk between macrophages and trophoblasts at maternal-fetal microenvironment in normal pregnancy.

U3-1402 sensitizes HER3-expressing tumors to PD-1 blockade by immune activation

Immunotherapy targeting programmed cell death-1 (PD-1) induces durable antitumor efficacy in many types of cancer. However, such clinical benefit is limited because of the insufficient reinvigoration of antitumor immunity with the drug alone; therefore, rational therapeutic combinations are required to improve its efficacy. In our preclinical study, we evaluated the antitumor effect of U3-1402, a human epidermal growth factor receptor 3-targeting (HER3-targeting) antibody-drug conjugate, and its potential synergism with PD-1 inhibition. Using a syngeneic mouse tumor model that is refractory to anti-PD-1 therapy, we found that treatment with U3-1402 exhibited an obvious antitumor effect via direct lysis of tumor cells. Disruption of tumor cells by U3-1402 enhanced the infiltration of innate and adaptive immune cells. Chemotherapy with exatecan derivative (Dxd, the drug payload of U3-1402) revealed that the enhanced antitumor immunity produced by U3-1402 was associated with the induction of alarmins, including high-mobility group box-1 (HMGB-1), via tumor-specific cytotoxicity. Notably, U3-1402 significantly sensitized the tumor to PD-1 blockade, as a combination of U3-1402 and the PD-1 inhibitor significantly enhanced antitumor immunity. Further, clinical analyses indicated that tumor-specific HER3 expression was frequently observed in patients with PD-1 inhibitor-resistant solid tumors. Overall, U3-1402 is a promising candidate as a partner of immunotherapy for such patients.

Dioscin elicits anti-tumour immunity by inhibiting macrophage M2 polarization via JNK and STAT3 pathways in lung cancer

Tumour‐associated macrophage (TAM) is an important component in tumour microenvironment. Generally, TAM exhibits the function of M2‐like macrophage, which was closely related to angiogenesis and tumour progression. Dioscin, a natural steroidal saponin, has shown its powerful anti‐tumour activity recently. However, the mechanism of dioscin involved in immune regulation is still obscure. Here, we observed dioscin induced macrophage M2‐to‐M1 phenotype transition in vitro and inhibited IL‐10 secretion. Meanwhile, the phagocytosis of macrophages was enhanced. In subcutaneous lung tumour models, dioscin inhibited the augmentation of M2 macrophage populations. Furthermore, dioscin down‐regulated STAT3 and JNK signalling pathways in macrophages in vitro. In BMDMs, activating JNK and inhibiting STAT3 induce macrophages to M1 polarization while inhibiting JNK and activating STAT3 to M2 polarization. Additionally, condition mediums from dioscin‐pre‐treated macrophages inhibited the migration of 3LL cells and the tube‐formation capacity of HUVECs. What's more, dioscin‐mediated macrophage polarization inhibited the in vivo metastasis of 3LL cells. In conclusion, dioscin may act as a new anti‐tumour agent by inhibiting TAMs via JNK and STAT3 pathways in lung cancer.

Identification of a Hypoxia-Associated Signature for Lung Adenocarcinoma

Background

A hypoxia microenvironment plays a role in the initiation and progression of many cancer types, but its involvement in lung adenocarcinoma is still unclear. This study aimed to explore the potential correlation between hypoxia and lung adenocarcinoma and establish the hypoxia-associated gene signature in lung adenocarcinoma.

Methods

Lung adenocarcinoma cases were retrieved from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) databases. The genes to be included in the hypoxia-associated signature were selected by performing univariate Cox regression analysis and lasso regression analysis. Then, the gene signature was verified by performing a survival analysis and constructing the multiple receiver operating characteristic (ROC) curve. The CIBERSORT tool was then used to investigate the potential correlation between the gene signature and immune cells. Moreover, a nomogram was constructed and evaluated by calculating the C-index.

Results

Four genes (XPNPEP1, ANGPTL4, SLC2A1, and PFKP) were included in the final signature. The results showed that patients in the high-risk group showed worse survival than those in the low-risk group. Moreover, we found two types of immune cells (memory activated CD4⁺ T cell and M0 macrophages) which showed a significant infiltration in the tissues of the high-risk group patients.

Conclusion

The hypoxia-associated gene signature established and validated in this study could be used as a potential prognostic factor in lung adenocarcinoma and may guide the immunotherapy choice.

Hypoxia-induced alternative splicing: the 11th Hallmark of Cancer

Hypoxia-induced alternative splicing is a potent driving force in tumour pathogenesis and progression. In this review, we update currents concepts of hypoxia-induced alternative splicing and how it influences tumour biology. Following brief descriptions of tumour-associated hypoxia and the pre-mRNA splicing process, we review the many ways hypoxia regulates alternative splicing and how hypoxia-induced alternative splicing impacts each individual hallmark of cancer. Hypoxia-induced alternative splicing integrates chemical and cellular tumour microenvironments, underpins continuous adaptation of the tumour cellular microenvironment responsible for metastatic progression and plays clear roles in oncogene activation and autonomous tumour growth, tumor suppressor inactivation, tumour cell immortalization, angiogenesis, tumour cell evasion of programmed cell death and the anti-tumour immune response, a tumour-promoting inflammatory response, adaptive metabolic re-programming, epithelial to mesenchymal transition, invasion and genetic instability, all of which combine to promote metastatic disease. The impressive number of hypoxia-induced alternative spliced protein isoforms that characterize tumour progression, classifies hypoxia-induced alternative splicing as the 11th hallmark of cancer, and offers a fertile source of potential diagnostic/prognostic markers and therapeutic targets.

Determination of a Tumor-Promoting Microenvironment in Recurrent Medulloblastoma: A Multi-Omics Study of Cerebrospinal Fluid

Molecular classification of medulloblastoma (MB) is well-established and reflects the cell origin and biological properties of tumor cells. However, limited data is available regarding the MB tumor microenvironment. Here, we present a mass spectrometry-based multi-omics pilot study of cerebrospinal fluid (CSF) from recurrent MB patients. A group of age-matched patients without a neoplastic disease was used as control cohort. Proteome profiling identified characteristic tumor markers, including FSTL5, ART3, and FMOD, and revealed a strong prevalence of anti-inflammatory and tumor-promoting proteins characteristic for alternatively polarized myeloid cells in MB samples. The up-regulation of ADAMTS1, GAP43 and GPR37 indicated hypoxic conditions in the CSF of MB patients. This notion was independently supported by metabolomics, demonstrating the up-regulation of tryptophan, methionine, serine and lysine, which have all been described to be induced upon hypoxia in CSF. While cyclooxygenase products were hardly detectable, the epoxygenase product and beta-oxidation promoting lipid hormone 12,13-DiHOME was found to be strongly up-regulated. Taken together, the data suggest a vicious cycle driven by autophagy, the formation of 12,13-DiHOME and increased beta-oxidation, thus promoting a metabolic shift supporting the formation of drug resistance and stem cell properties of MB cells. In conclusion, the different omics-techniques clearly synergized and mutually supported a novel model for a specific pathomechanism.

Targeting Mononuclear Phagocyte Receptors in Cancer Immunotherapy: New Perspectives of the Triggering Receptor Expressed on Myeloid Cells (TREM-1)

Inflammatory cells are major players in the onset of cancer. The degree of inflammation and type of inflammatory cells in the tumor microenvironment (TME) are responsible for tilting the balance between tumor progression and regression. Cancer-related inflammation has also been shown to influence the efficacy of conventional therapy. Mononuclear phagocytes (MPs) represent a major component of the inflammatory circuit that promotes tumor progression. Despite their potential to activate immunosurveillance and exert anti-tumor responses, MPs are subverted by the tumor to support its growth, immune evasion, and spread. MP responses in the TME are dictated by a network of stimuli integrated through the cross-talk between activatory and inhibitory receptors. Alterations in receptor expression/signaling can create excessive inflammation and, when chronic, promote tumorigenesis. Research advances have led to the development of new therapeutic strategies aimed at receptor targeting to induce a tumor-infiltrating MP switch from a cancer-supportive toward an anti-tumor phenotype, demonstrating efficacy in different human cancers. This review provides an overview of the role of MP receptors in inflammation-mediated carcinogenesis and discusses the most recent updates regarding their targeting for immunotherapeutic purposes. We focus in particular on the TREM-1 receptor, a major amplifier of MP inflammatory responses, highlighting its relevance in the development and progression of several types of inflammation-associated malignancies and the promises of its inhibition for cancer immunotherapy.

Antibody combinations for optimized staining of macrophages in human lung tumours

The analysis of tumour-associated macrophages (TAMs) has a high potential to predict cancer recurrence and response to immunotherapy. However, the heterogeneity of TAMs poses a challenge for quantitative and qualitative measurements. Here, we critically evaluated by immunohistochemistry and flow cytometry two commonly used pan-macrophage markers (CD14 and CD68) as well as some suggested markers for tumour-promoting M2 macrophages (CD163, CD204, CD206 and CD209) in human non-small cell lung cancer (NSCLC). Tumour, non-cancerous lung tissue and blood were investigated. For immunohistochemistry, CD68 was confirmed to be a useful pan-macrophage marker although careful selection of antibody was found to be critical. The widely used anti-CD68 antibody clone KP-1 stains both macrophages and neutrophils, which is problematic for TAM quantification because lung tumours contain many neutrophils. For TAM counting in tumour sections, we recommend combined labelling of CD68 with a cell membrane marker such as CD14, CD163 or CD206. In flow cytometry, the commonly used combination of CD14 and HLA-DR was found to not be optimal because some TAMs do not express CD14. Instead, combined staining of CD68 and HLA-DR is preferable to gate all TAMs. Concerning macrophage phenotypic markers, the scavenger receptor CD163 was found to be expressed by a substantial fraction (50%-86%) of TAMs with a large patient-to-patient variation. Approximately 50% of TAMs were positive for CD206. Surprisingly, there was no clear overlap between CD163 and CD206 positivity, and three distinct TAM sub-populations were identified in NSCLC tumours: CD163⁺ CD206⁺ , CD163⁺ CD206^- and CD163^- CD206^- . This work should help develop macrophage-based prognostic tools for cancer.

Signaling of Macrophages that Contours the Tumor Microenvironment for Promoting Cancer Development

The immune response is critical in the maintenance of an organism’s health. The immune response can be broken down into two groups. The innate response, which is fast-acting and rids the body of most foreign material before infection occurs, and the adaptive response, a more specific defense against pathogen composed mostly of antibody production and killer cells. Linking the two responses via cytokine and chemokine secretion are macrophages, motile phagocytic cells that ingest and present foreign material playing a role in the innate and adaptive immune response. Although macrophages are necessary for the survival of an organism, studies have also shown macrophages play a more sinister role in the initiation, progression, and metastasis in tumorous cells. In this comprehensive review, we show how macrophages induce such a response through abnormal cellular signaling and creating a cellular microenvironment conducive for tumor growth and metastasis, as well as the future outlook of this field.

Effect and Molecular Mechanisms of Traditional Chinese Medicine on Tumor Targeting Tumor-Associated Macrophages

Traditional Chinese medicine (TCM) has been used as a significant cancer treatment method for many years in China. It has been demonstrated that TCM could assist in inhibiting the growth of tumors and prolonging the survival rates of cancer patients. Although the mechanism of TCM are still not clear, accumulating evidence has shown that they may be related to the tumor microenvironment (TME). Tumor-associated macrophages (TAMs) play a significant role in TME and are polarized to two phenotypes, M1 (classically activated) and M2 (alternatively activated) TAMs. The two different phenotypes of TAMs play converse roles in the TME and M2-polarized tumor-associated macrophages (M2-TAMs) always lead to poor prognosis in cancer patients compared to M1-polarized tumor-associated macrophages (M1-TAMs). In this review, the potential correlation between TCM and TAMs (especially the M2 phenotype) in tumor progression and promising TCM strategies targeting TAMs in cancer are discussed.

Nurse-Delivered Brief Behavioral Treatment for Insomnia in Lung Cancer Survivors: A Pilot RCT

Objective/Background: Insomnia occurs in 50 to 80% of lung cancer survivors. Cognitive behavioral therapy is the standard treatment for insomnia (CBTI); however, treatment length and lack of psychologists trained in CBTI limits access. Brief Behavioral Treatment for Insomnia (BBTI), a nurse-delivered modified CBTI, is proposed. This feasibility pilot study sought to compare the BBTI intervention to attention control Healthy Eating Program (HEP) for insomnia in lung cancer survivors. Participants: The participants comprised adults, 21 years of age or older with insomnia and stage I/II non-small cell lung cancer, more than 6 weeks from surgery and living in Western NY. Methods: Participants (n = 40) were randomly assigned to an experimental (BBTI) or attention control condition (Healthy Eating Program). Thirty participants completed the study. Results: Participants were 66 years of age (± 7.6; range 53-82), 40% (n = 16) male, 87.5% (n = 35) Caucasian, 50% (n = 20) married, BMI 27.7 (± 5.8), and 12% (n = 5) never smokers. Baseline sleep diary sleep efficiency, ISI and other baseline covariates were balanced between the groups. Sleep efficiency improved ≥85% in BBTI group (p = .02), but not in HEP control group (p = 1.00). Mean ISI for BBTI and attention control were 6.40 ± 4.98 and 14.10 ± 4.48 (p = .001) respectively. In addition, BBTI group mean total FACT-L score improved by 6.66 points from baseline while HEP group score worsened (p = .049). Conclusions: BBTI is a practical, evidence-based, clinically relevant intervention that improved sleep and quality of life in lung cancer survivors with insomnia. Additional research to evaluate efficacy, duration, and implementation strategies are essential.

Neutrophil Metabolic Shift during their Lifecycle: Impact on their Survival and Activation

Polymorphonuclear neutrophils (PMNs) are innate immune cells, which represent 50% to 70% of the total circulating leukocytes. How PMNs adapt to various microenvironments encountered during their life cycle, from the bone marrow, to the blood plasma fraction, and to inflamed or infected tissues remains largely unexplored. Metabolic shifts have been reported in other immune cells such as macrophages or lymphocytes, in response to local changes in their microenvironment, and in association with a modulation of their pro-inflammatory or anti-inflammatory functions. The potential contribution of metabolic shifts in the modulation of neutrophil activation or survival is anticipated even though it is not yet fully described. If neutrophils are considered to be mainly glycolytic, the relative importance of alternative metabolic pathways, such as the pentose phosphate pathway, glutaminolysis, or the mitochondrial oxidative metabolism, has not been fully considered during activation. This statement may be explained by the lack of knowledge regarding the local availability of key metabolites such as glucose, glutamine, and substrates, such as oxygen from the bone marrow to inflamed tissues. As highlighted in this review, the link between specific metabolic pathways and neutrophil activation has been outlined in many reports. However, the impact of neutrophil activation on metabolic shifts' induction has not yet been explored. Beyond its importance in neutrophil survival capacity in response to available metabolites, metabolic shifts may also contribute to neutrophil population heterogeneity reported in cancer (tumor-associated neutrophil) or auto-immune diseases (Low/High Density Neutrophils). This represents an active field of research. In conclusion, the characterization of neutrophil metabolic shifts is an emerging field that may provide important knowledge on neutrophil physiology and activation modulation. The related question of microenvironmental changes occurring during inflammation, to which neutrophils will respond to, will have to be addressed to fully appreciate the importance of neutrophil metabolic shifts in inflammatory diseases.

Altered expression of miR-181 affects cell fate and targets drug resistance-related mechanisms

MicroRNAs (miRNAs) are non-coding transcripts which regulate genetic and epigenetic events by interfering with mRNA translation. miRNAs are involved in regulation of cell fate due to their ability of interfering with physiological or pathological processes. In this review paper, we evaluate the role of miR-181 family members as prognostic or diagnostic markers or therapeutic targets in malignant pathologies in connection with the main hallmarks of cancer that are modulated by the family. Also, we take over the dual role of this family in dependency with the tumour suppressor and oncogenic features presented in cell and cancer type specific manner. Restoration of the altered expression levels contributes to the activation of cell death pathways or to a reduction in the invasion and migration mechanism; moreover, the mechanism of drug resistance is also modulated by miR-181 sequences with important applications in therapeutic strategies for malignant cells sensitisation. Overall, the main miR-181 family regulatory mechanisms are presented in a cancer specific context, emphasizing the possible clinical application of this family in terms of novel diagnosis and therapy approaches.

Hypoxia as a barrier to immunotherapy in pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma (PDA) is a lethal disease with limited response to cytotoxic chemoradiotherapy, as well as newer immunotherapies. The PDA tumor microenvironment contains infiltrating immune cells including cytotoxic T cells; however, there is an overall immunosuppressive milieu. Hypoxia is a known element of the solid tumor microenvironment and may promote tumor survival. Through various mechanisms including, but not limited to, those mediated by HIF-1α, hypoxia also leads to increased tumor proliferation and metabolic changes. Furthermore, epithelial to mesenchymal transition is promoted through several pathways, including NOTCH and c-MET, regulated by hypoxia. Hypoxia-promoted changes also contribute to the immunosuppressive phenotype seen in many different cell types within the microenvironment and thereby may inhibit an effective immune system response to PDA. Pancreatic stellate cells (PSCs) and myofibroblasts appear to contribute to the recruitment of myeloid derived suppressor cells (MDSCs) and B cells in PDA via cytokines increased due to hypoxia. PSCs also increase collagen secretion in response to HIF-1α, which promotes a fibrotic stroma that alters T cell homing and migration. In hypoxic environments, B cells contribute to cytotoxic T cell exhaustion and produce chemokines to attract more immunosuppressive regulatory T cells. MDSCs inhibit T cell metabolism by hoarding key amino acids, modulate T cell homing by cleaving L-selectin, and prevent T cell activation by increasing PD-L1 expression. Immunosuppressive M2 phenotype macrophages promote T cell anergy via increased nitric oxide (NO) and decreased arginine in hypoxia. Increased numbers of regulatory T cells are seen in hypoxia which prevent effector T cell activation through cytokine production and increased CTLA-4. Effective immunotherapy for pancreatic adenocarcinoma and other solid tumors will need to help counteract the immunosuppressive nature of hypoxia-induced changes in the tumor microenvironment. Promising studies will look at combination therapies involving checkpoint inhibitors, chemokine inhibitors, and possible targeting of hypoxia. While no model is perfect, assuring that models incorporate the effects of hypoxia on cancer cells, stromal cells, and effector immune cells will be crucial in developing successful therapies.