CXCL12/CXCR4 pathway orchestrates CSC-like properties by CAF recruited tumor associated macrophage in OSCC. Exp Cell Res. 2019;378:131-138. [PMID: 30857971 DOI: 10.1016/j.yexcr.2019.03.013]

Tumor-infiltrating myeloid cells; mechanisms, functional significance, and targeting in cancer therapy

Tumor-infiltrating myeloid cells (TIMs), which encompass tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), myeloid-derived suppressor cells (MDSCs), and tumor-associated dendritic cells (TADCs), are of great importance in tumor microenvironment (TME) and are integral to both pro- and anti-tumor immunity. Nevertheless, the phenotypic heterogeneity and functional plasticity of TIMs have posed challenges in fully understanding their complexity roles within the TME. Emerging evidence suggested that the presence of TIMs is frequently linked to prevention of cancer treatment and improvement of patient outcomes and survival. Given their pivotal function in the TME, TIMs have recently been recognized as critical targets for therapeutic approaches aimed at augmenting immunostimulatory myeloid cell populations while depleting or modifying those that are immunosuppressive. This review will explore the important properties of TIMs related to immunity, angiogenesis, and metastasis. We will also document the latest therapeutic strategies targeting TIMs in preclinical and clinical settings. Our objective is to illustrate the potential of TIMs as immunological targets that may improve the outcomes of existing cancer treatments.

CD105+ fibroblasts support an immunosuppressive niche in women at high risk of breast cancer initiation

BACKGROUND

Aging is the greatest risk factor for breast cancer, and although epithelial cells are the source of carcinomas, epithelial changes alone do not fully explain cancer susceptibility. Fibroblasts and macrophages are key stromal constituents around the cells of origin for cancer in breast tissue. With age, macrophages surrounding terminal ductal lobular units (TDLUs) become increasingly immunosuppressive. CD105+ fibroblasts intercalate within TDLUs, drive luminal differentiation, and give rise to immunosuppressive cancer-associated fibroblasts in other tissues. We propose that differences in fibroblasts are a crucial component of the stroma that shapes cancer susceptibility.

METHODS

Primary peri-epithelial fibroblast cultures were established from prophylactic and reduction mammoplasties from 30 women ranging in age from 16 to 70 years and from BRCA1 mutation carriers. Growth characteristics, transcriptional profiles, differentiation potential, and secreted proteins were profiled for fibroblast subtypes from diverse donors. Co-cultures with fibroblasts, macrophages, and T cells were used to ascertain the functional role played by CD105+ fibroblasts in immune cell modulation.

RESULTS

We found that peri-epithelial CD105+ fibroblasts are enriched in older women as well as women who carry BRCA1 mutations. These CD105+ fibroblasts exhibit robust adipogenesis and secrete factors related to macrophage polarization. Macrophages cocultured with fibroblasts better maintain or enhance polarization states than media alone. CD105+ fibroblasts increased expression of immunosuppressive macrophage genes. CD105+ fibroblasts supported anti-inflammatory macrophage-mediated suppression of T cell proliferation, whereas CD105- fibroblasts significantly reduced the suppressive effect of anti-inflammatory macrophages on T cell proliferation.

CONCLUSIONS

Establishment of a coculture system to dissect the molecular circuits between CD105+ fibroblasts and macrophages that drive immunosuppressive macrophage polarization has broad utility in understanding mammary gland development and events that precede cancer initiation. CD105+ fibroblasts and macrophages may coordinate to suppress immunosurveillance and increase breast cancer susceptibility.

Macrophages and the immune microenvironment in OPMDs: a systematic review of the literature

Background

In the presence of cancers, Tumor Associated Macrophages have a well-established role, but the literature provides limited evidence regarding their involvement in the onset and malignant transformation of Oral Potentially Malignant Disorders (OPMDs).

Objectives

The present systematic review aimed to collect evidence on the presence and characterization of macrophages in the microenvironment of OPMDs.

Data sources

PubMed, Scopus, EMBASE, Web of Science.

Study eligibility criteria

Ex vivo or in silico human studies reporting original quantitative data on macrophage infiltration in OPMDs or Oral Epithelial Dysplasia (OED), published from 1990 onward.

Results

Thirty-seven studies were included for qualitative analysis. Investigated OPMDs included: oral leukoplakia, oral lichen planus, oral lichenoid lesions, proliferative leukoplakia, oral submucous fibrosis, actinic cheilitis, chronic graft vs. host disease.

Discussion

Even though the heterogeneity of data from the included studies prevents a meta-analysis, the reported results are quite consistent in supporting an increasing macrophage infiltration from normal mucosa to OPMDs, OED, and Oral Squamous Cell Carcinoma (OSCC). An M1 pro-inflammatory polarization is prevalent in OPMDs, with a shift toward an M2 pro-tumorigenic polarization in moderate-severe OED and OSCC. Several novel markers including STAT1, IDO, PD-L1, APOE, ITGB2 appear to be able to identify macrophage clusters involved in pro-inflammatory or pro-tumorigenic pathways.

Conclusions

Evidence from the present review supports an active role of macrophages in regulating immune suppression, oncogenesis, and tumor progression in OPMDs and during the transition to OSCC. Future research should focus not merely on cell quantification and general M1/M2 polarization but rather on the expression of specific markers potentially linked to immunomodulatory pathways involved in oncogenesis.

CD105+ fibroblasts support an immunosuppressive niche in women at high risk of breast cancer initiation

BACKGROUND

Aging is the greatest risk factor for breast cancer, and although epithelial cells are the source of carcinomas, epithelial changes alone do not fully explain cancer susceptibility. Fibroblasts and macrophages are key stromal constituents around the cells of origin for cancer in breast tissue. With age, macrophages surrounding terminal ductal lobular units (TDLUs) become increasingly immunosuppressive. CD105 + fibroblasts intercalate within TDLUs, drive luminal differentiation, and give rise to immunosuppressive cancer-associated fibroblasts in other tissues. We propose that differences in fibroblasts are a crucial component of the stroma that shapes cancer susceptibility.

METHODS

Primary fibroblast cultures were established from prophylactic and reduction mammoplasties from women ranging in age from 16 to 70 years and breast cancer risk ( BRCA1 mutation carriers). Growth characteristics, transcriptional profiles, differentiation potential, and secreted proteins were profiled for fibroblast subtypes from diverse donors. Co-cultures with fibroblasts, monocytes, macrophages, and T cells were used to ascertain the functional role played by CD105 + fibroblasts in immune cell modulation.

RESULTS

We found that peri-epithelial CD105 + fibroblasts are enriched in older women as well as women who carry BRCA1 mutations. These CD105 + fibroblasts exhibit robust adipogenesis and secrete factors related to macrophage polarization. Macrophages cocultured with fibroblasts better maintain or enhance polarization states than media alone. CD105 + fibroblasts increased expression of immunosuppressive macrophage genes. CD105 + fibroblasts supported anti-inflammatory macrophage-mediated suppression of T cell proliferation, whereas CD105 - fibroblasts significantly reduced the suppressive effect of anti-inflammatory macrophages on T cell proliferation.

CONCLUSIONS

Establishment of a coculture system to dissect the molecular circuits between CD105 + fibroblasts and macrophages that drive immunosuppressive macrophage polarization has broad utility in understanding mammary gland development and events that precede cancer initiation. CD105 + fibroblasts and macrophages may coordinate to suppress immunosurveillance and increase breast cancer susceptibility.

Recent developments in myeloid immune modulation in cancer therapy

Myeloid cells play a crucial dual role in cancer progression and response to therapy, promoting tumor growth, enabling immune suppression, and contributing to metastatic spread. The ability of these cells to modulate the immune system has made them attractive targets for therapeutic strategies aimed at shifting their function from tumor promotion to fostering antitumor immunity. Therapeutic approaches targeting myeloid cells focus on modifying their numbers, genetics, metabolism, and interactions within the tumor microenvironment. These strategies aim to reverse their suppressive functions and redirect them to support antitumor immune responses by inhibiting immunosuppressive pathways, targeting specific receptors, and promoting their differentiation into less immunosuppressive phenotypes. Here, we discuss recent approaches to clinically target tumor myeloid cells, focusing on reprogramming myeloid cells to promote antitumor immunity.

Cancer associated fibroblasts in cancer development and therapy

Cancer-associated fibroblasts (CAFs) are key players in cancer development and therapy, and they exhibit multifaceted roles in the tumor microenvironment (TME). From their diverse cellular origins, CAFs undergo phenotypic and functional transformation upon interacting with tumor cells and their presence can adversely influence treatment outcomes and the severity of the cancer. Emerging evidence from single-cell RNA sequencing (scRNA-seq) studies have highlighted the heterogeneity and plasticity of CAFs, with subtypes identifiable through distinct gene expression profiles and functional properties. CAFs influence cancer development through multiple mechanisms, including regulation of extracellular matrix (ECM) remodeling, direct promotion of tumor growth through provision of metabolic support, promoting epithelial-mesenchymal transition (EMT) to enhance cancer invasiveness and growth, as well as stimulating cancer stem cell properties within the tumor. Moreover, CAFs can induce an immunosuppressive TME and contribute to therapeutic resistance. In this review, we summarize the fundamental knowledge and recent advances regarding CAFs, focusing on their sophisticated roles in cancer development and potential as therapeutic targets. We discuss various strategies to target CAFs, including ECM modulation, direct elimination, interruption of CAF-TME crosstalk, and CAF normalization, as approaches to developing more effective treatments. An improved understanding of the complex interplay between CAFs and TME is crucial for developing new and effective targeted therapies for cancer.

IL6-Dependent PIEZO1 Activation Promotes M1-Mediated Orthodontic Root Resorption via CXCL12/CXCR4

Orthodontic root resorption (ORR) is a common yet significant complication of orthodontic treatment, largely driven by interactions between periodontal ligament cells (PDLCs) and M1 macrophages. Despite the clinical relevance of ORR, the role of mechanosensitive ion channels in PDLC-mediated ORR and the underlying mechanisms regulating inflammatory cell recruitment remain poorly understood. Here, we identified PIEZO1 as a critical mechanosensitive ion channel that modulates monocyte recruitment and ORR. Using in vivo models treated with the PIEZO1 activator Yoda1 and inhibitor AAV-shPiezo1, we demonstrated that PIEZO1 activation promoted the recruitment of Ly6Chi inflammatory monocytes and exacerbated ORR. In contrast, PIEZO1 inhibition attenuated ORR and the accumulation of M1 macrophages. Mechanistically, PIEZO1 positively regulated the C-X-C motif chemokine 12 (CXCL12) and its receptor, C-X-C chemokine receptor type 4 (CXCR4). Blocking the CXCL12/CXCR4 axis using the CXCR4 antagonist AMD3100 significantly alleviated ORR, reversed M1 macrophage accumulation, and mitigated the recruitment of CD11b+Ly6Chi monocytes. Transwell migration assays with application of the PIEZO1 activator Yoda1 and PIEZO1 inhibitor GsMTX4 consistently confirmed the PIEZO1/CXCL12/CXCR4 axis as a key driver of PDLC-monocyte interactions. Notably, PIEZO1 overactivation was linked to excessive IL-6 production, and IL-6 deficiency inhibited the activation of PIEZO1 induced by Yoda1, leading to attenuation of ORR, M1 macrophage accumulation, and CXCL12/CXCR4 axis activation. Collectively, these findings reveal PIEZO1 in PDLCs as a pivotal modulator of inflammatory monocyte recruitment via the CXCL12/CXCR4 axis in ORR, with IL-6 playing an essential role in PIEZO1 activation. This study provides new insights into the molecular crosstalk between PDLCs and macrophages, offering potential therapeutic targets for mitigating ORR in orthodontic patients.

Regulation of cancer-associated fibroblasts for enhanced cancer immunotherapy using advanced functional nanomedicines: an updated review

The tumor microenvironment (TME) is a complex and dynamic ecosystem that plays a critical role in cancer progression. It comprises various cell types, including immune cells, tumor cells, and stromal cells. Among these, cancer-associated fibroblasts (CAFs) represent a heterogeneous population with diverse origins, phenotypes, and functions. Activated CAFs secrete multiple factors that promote tumor growth, migration, angiogenesis, and contribute to chemoresistance. Additionally, CAFs secrete extracellular matrix (ECM) components, such as collagen, which form a physical barrier that hinders the penetration of chemotherapeutic and immunotherapeutic agents. This ECM also influences immune cell infiltration, impeding their ability to effectively target tumor cells. As a result, modulating the activity of CAFs has emerged as a promising strategy to enhance the efficacy of tumor immunotherapy. Nano-delivery systems, constructed from various nanomaterials with high targeting specificity and biocompatibility, offer a compelling approach to deliver therapeutic agents or immunomodulatory factors directly to CAFs. This modulation can alter CAF function, reduce their tumor-promoting effects, and thereby improve the outcomes of immunotherapy. This review provides an in-depth exploration of the origins, functions, and interactions of CAFs within the TME, particularly in the context of immune suppression. Furthermore, it discusses the potential applications of functional nanocarrifers in modulating CAFs and enhancing the effectiveness of tumor immunotherapy, highlighting the significant progress and potential of nanotechnology in this area.

OSR1 suppresses oral squamous cell carcinoma proliferation and migration via the AXIN2/β-catenin pathway

OBJECTIVES

The odd-skipped related transcription factor 1 (OSR1) gene exerts distinct regulatory effects on tumorigenesis and development in various cancer types. However, the precise role of OSR1 in oral squamous cell carcinoma (OSCC) remains to be elucidated.

METHODS

GEPIA 2 and TCGA databases were utilized to analyze the OSR1 expression in head and neck squamous cell carcinoma (HNSC) patients and its impact on prognosis. Hematoxylin-eosin staining, immunohistochemistry, immunofluorescence, western blotting, and RT-qPCR were employed to detect the OSR1 expression in OSCC tissues and cells. Lentivirus transfection was utilized for overexpression and downexpression of OSR1 in OSCC. CCK8 cell proliferation assay, colony formation and cell scratch assay were conducted to investigate the effects of OSR1 on biological behavior of OSCC cells. Western blotting and RT-qPCR were applied to investigate the regulatory mechanism of OSR1 on AXIN2/β-catenin signaling pathway.

RESULTS

OSR1 expression was significantly decreased in HNSC patients, OSCC tissues and cells, leading to a decrease in 5-year survival rate. OSR1 overexpression inhibited the proliferation and migration of OSCC cells, and the AXIN2/β-catenin signaling pathway was inhibited. Silencing OSR1 had the opposite effect.

CONCLUSIONS

OSR1 functioned as a tumor suppressor gene in OSCC proliferation and migration by regulating the AXIN2/β-catenin signaling pathway.

Cancer stem cells and tumor-associated macrophages as mates in tumor progression: mechanisms of crosstalk and advanced bioinformatic tools to dissect their phenotypes and interaction

Cancer stem cells (CSCs) are a small subset within the tumor mass significantly contributing to cancer progression through dysregulation of various oncogenic pathways, driving tumor growth, chemoresistance and metastasis formation. The aggressive behavior of CSCs is guided by several intracellular signaling pathways such as WNT, NF-kappa-B, NOTCH, Hedgehog, JAK-STAT, PI3K/AKT1/MTOR, TGF/SMAD, PPAR and MAPK kinases, as well as extracellular vesicles such as exosomes, and extracellular signaling molecules such as cytokines, chemokines, pro-angiogenetic and growth factors, which finely regulate CSC phenotype. In this scenario, tumor microenvironment (TME) is a key player in the establishment of a permissive tumor niche, where CSCs engage in intricate communications with diverse immune cells. The "oncogenic" immune cells are mainly represented by B and T lymphocytes, NK cells, and dendritic cells. Among immune cells, macrophages exhibit a more plastic and adaptable phenotype due to their different subpopulations, which are characterized by both immunosuppressive and inflammatory phenotypes. Specifically, tumor-associated macrophages (TAMs) create an immunosuppressive milieu through the production of a plethora of paracrine factors (IL-6, IL-12, TNF-alpha, TGF-beta, CCL1, CCL18) promoting the acquisition by CSCs of a stem-like, invasive and metastatic phenotype. TAMs have demonstrated the ability to communicate with CSCs via direct ligand/receptor (such as CD90/CD11b, LSECtin/BTN3A3, EPHA4/Ephrin) interaction. On the other hand, CSCs exhibited their capacity to influence immune cells, creating a favorable microenvironment for cancer progression. Interestingly, the bidirectional influence of CSCs and TME leads to an epigenetic reprogramming which sustains malignant transformation. Nowadays, the integration of biological and computational data obtained by cutting-edge technologies (single-cell RNA sequencing, spatial transcriptomics, trajectory analysis) has significantly improved the comprehension of the biunivocal multicellular dialogue, providing a comprehensive view of the heterogeneity and dynamics of CSCs, and uncovering alternative mechanisms of immune evasion and therapeutic resistance. Moreover, the combination of biology and computational data will lead to the development of innovative target therapies dampening CSC-TME interaction. Here, we aim to elucidate the most recent insights on CSCs biology and their complex interactions with TME immune cells, specifically TAMs, tracing an exhaustive scenario from the primary tumor to metastasis formation.

Targeting glutamine metabolism crosstalk with tumor immune response

Glutamine, akin to glucose, is a fundamental nutrient for human physiology. Tumor progression is often accompanied by elevated glutamine consumption, resulting in a disrupted nutritional balance and metabolic reprogramming within the tumor microenvironment. Furthermore, immune cells, which depend on glutamine for metabolic support, may experience functional impairments and dysregulation. Although the role of glutamine in tumors has been extensively studied, the specific impact of glutamine competition on immune responses, as well as the precise cellular alterations within immune cells, remains incompletely understood. In this review, we summarize the consequences of glutamine deprivation induced by tumor-driven glutamine uptake on immune cells, assessing the underlying mechanisms from the perspective of various components of the immune microenvironment. Additionally, we discuss the potential synergistic effects of glutamine supplementation and immunotherapy, offering insights into future research directions. This review provides compelling evidence for the integration of glutamine metabolism and immunotherapy as a promising strategy in cancer therapy.

Effect of fibroblast heterogeneity on prognosis and drug resistance in high-grade serous ovarian cancer

Tumor heterogeneity is associated with poor prognosis and drug resistance, leading to therapeutic failure. Here, we used tumor evolution analysis to determine the intra- and intertumoral heterogeneity of high-grade serous ovarian cancer (HGSOC) and analyze the correlation between tumor heterogeneity and prognosis, as well as chemotherapy response, through single-cell and spatial transcriptomic analysis. We collected and curated 28 HGSOC patients' single-cell transcriptomic data from five datasets. Then, we developed a novel text-mining-based machine-learning approach to deconstruct the evolutionary patterns of tumor cell functions. We then identified key tumor-related genes within different evolutionary branches, characterized the microenvironmental cell compositions that various functional tumor cells depend on, and analyzed the intra- and intertumoral heterogeneity as well as the tumor microenvironments. These analyses were conducted in relation to the prognosis and chemotherapy response in HGSOC patients. We validated our findings in two spatial and seven bulk transcriptomic datasets (total: 1,030 patients). Using transcriptomic clusters as proxies for functional clonality, we identified a significant increase in tumor cell state heterogeneity that was strongly correlated with patient prognosis and treatment response. Furthermore, increased intra- and intertumoral functional clonality was associated with the characteristics of cancer-associated fibroblasts (CAFs). The spatial proximity between CXCL12-positive CAFs and tumor cells, mediated through the CXCL12/CXCR4 interaction, was highly positively correlated with poor prognosis and chemotherapy resistance in HGSOC. Finally, we constructed a panel of 24 genes through statistical modeling that correlate with CXCL12-positive fibroblasts and can predict both prognosis and the response to chemotherapy in HGSOC patients. Our study offers insights into the collective behavior of tumor cell communities in HGSOC, as well as potential drivers of tumor evolution in response to therapy. There was a strong association between CXCL12-positive fibroblasts and tumor progression, as well as treatment outcomes.

Unveiling the contribution of tumor-associated macrophages in driving epithelial-mesenchymal transition: a review of mechanisms and therapeutic Strategies

Tumor-associated macrophages (TAMs), fundamental constituents of the tumor microenvironment (TME), significantly influence cancer development, primarily by promoting epithelial-mesenchymal transition (EMT). EMT endows cancer cells with increased motility, invasiveness, and resistance to therapies, marking a pivotal juncture in cancer progression. The review begins with a detailed exposition on the origins of TAMs and their functional heterogeneity, providing a foundational understanding of TAM characteristics. Next, it delves into the specific molecular mechanisms through which TAMs induce EMT, including cytokines, chemokines and stromal cross-talking. Following this, the review explores TAM-induced EMT features in select cancer types with notable EMT characteristics, highlighting recent insights and the impact of TAMs on cancer progression. Finally, the review concludes with a discussion of potential therapeutic targets and strategies aimed at mitigating TAM infiltration and disrupting the EMT signaling network, thereby underscoring the potential of emerging treatments to combat TAM-mediated EMT in cancer. This comprehensive analysis reaffirms the necessity for continued exploration into TAMs' regulatory roles within cancer biology to refine therapeutic approaches and improve patient outcomes.

Establishment of Early Blood Perfusion Promotes CXCL12 Expression and Recruits Monocytes/Macrophages in Damaged Adipose Tissue in Mice Model

BACKGROUND

Blood perfusion in the recipient site is important for adipose tissue repair after fat grafting. It delivers host-derived macrophages derived from monocytes in bone marrow to initiate inflammatory reactions and regenerative responses. According to the ability of CXCL12, a stromal cell-derived factor, to recruit monocytes/macrophages, we studied its effect on adipose tissue repair and regeneration under ischemic and normal conditions.

METHODS

Each inguinal fat pad was crushed for 30 seconds with a clamp in mice (n = 35). The left inguinal vessels were divided and cut off (ischemic group), while the right inguinal vessels were kept patent (control group). Seven animals were sacrificed at 1, 3, 7, 14, and 30 days after surgery, and macrophages (Mac2 and CD206) and adipocytes (perilipin) were assessed. Levels of inflammatory factors (interleukin (IL)-1β, IL-6, and tumor necrosis factor-α) and CXCL12 were measured by quantitative PCR.

RESULTS

The number of macrophages was higher in the control group than in the ischemic group at day 3 (10.33 ± 2.40 vs. 1.33 ± 0.33, p = 0.021). The percentage of M2 macrophages was higher in the control group than in the ischemic group at day 7 (p<0.05). The levels of inflammatory factors and CXCL12 were higher in the control group than in the ischemic group at the early stage (p = 0.038).

CONCLUSIONS

Established blood perfusion leads to up-regulation of CXCL12 during adipose tissue repair and regeneration, which may increase recruitment of monocytes to damaged adipose tissue. These findings increase understanding of the cellular events involved in fat graft survival after grafting.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Molecular and epigenetic ex vivo profiling of testis cancer-associated fibroblasts and their interaction with germ cell tumor cells and macrophages

Germ cell tumors (GCT) are the most common solid tumors in young men of age 15 - 40. In previous studies, we profiled the interaction of GCT cells with cells of the tumor microenvironment (TM), which showed that especially the 3D interaction of fibroblasts (FB) or macrophages with GCT cells influenced the growth behavior and cisplatin response as well as the transcriptome and secretome of the tumor cells, suggesting that the crosstalk of these cells with GCT cells is crucial for tumor progression and therapy outcome. In this study, we shed light on the mechanisms of activation of cancer-associated fibroblasts (CAF) in the GCT setting and their effects on GCT cells lines and the monocyte cell line THP-1. Ex vivo cultures of GCT-derived CAF were established and characterized molecularly and epigenetically by performing DNA methylation arrays, RNA sequencing, and mass spectrometry-based secretome analysis. We demonstrated that the activation state of CAF is influenced by their former prevailing tumor environment in which they have resided. Hereby, we postulate that seminoma (SE) and embryonal carcinoma (EC) activate CAF, while teratoma (TER) play only a minor role in CAF formation. In turn, CAF influence proliferation and the expression of cisplatin sensitivity-related factors in GCT cells lines as well as polarization of in vitro-induced macrophages by the identified effector molecules IGFBP1, LGALS3BP, LYVE1, and PTX3. Our data suggests that the vital interaction of CAF with GCT cells and with macrophages has a huge influence on shaping the extracellular matrix as well as on recruitment of immune cells to the TM. In conclusion, therapeutically interfering with CAF and / or macrophages in addition to the standard therapy might slow-down progression of GCT and re-shaping of the TM to a tumor-promoting environment. Significance: The interaction of CAF with GCT and macrophages considerably influences the microenvironment. Thus, therapeutically interfering with CAF might slow-down progression of GCT and re-shaping of the microenvironment to a tumor-promoting environment.

Biomarkers Identification in the Microenvironment of Oral Squamous Cell Carcinoma: A Systematic Review of Proteomic Studies

An important determinant for oral squamous cell carcinoma (OSCC) onset and outcome is the composition of the tumor microenvironment (TME). Thus, the study of the interactions occurring among cancer cells, immune cells, and cancer-associated fibroblasts within the TME could facilitate the understanding of the mechanisms underlying OSCC development and progression, as well as of its sensitivity or resistance to the therapy. In this context, it must be highlighted that the characterization of TME proteins is enabled by proteomic methodologies, particularly mass spectrometry (MS). Aiming to identify TME protein markers employable for diagnosing and prognosticating OSCC, we have retrieved a total of 119 articles spanning 2001 to 2023, of which 17 have passed the selection process, satisfying all its criteria. We have found a total of 570 proteins detected by MS-based proteomics in the TME of OSCC; among them, 542 are identified by a single study, while 28 are cited by two or more studies. These 28 proteins participate in extracellular matrix remodeling and/or energy metabolism. Here, we propose them as markers that could be used to characterize the TME of OSCC for diagnostic/prognostic purposes. Noteworthy, most of the 28 individuated proteins share one feature: being modulated by the hypoxia that is present in the proliferating OSCC mass.

Macrophage polarization in the tumor microenvironment: Emerging roles and therapeutic potentials

The tumor microenvironment (TME) is a combination of tumor cells and indigenous host stroma, which consists of tumor-infiltrating immune cells, endothelial cells, fibroblasts, pericytes, and non-cellular elements. Tumor-associated macrophages (TAMs) represent the major tumor-infiltrating immune cell type and are generally polarized into two functionally contradictory subtypes, namely classical activated M1 macrophages and alternatively activated M2 macrophages. Macrophage polarization refers to how macrophages are activated at a given time and space. The interplay between the TME and macrophage polarization can influence tumor initiation and progression, making TAM a potential target for cancer therapy. Here, we review the latest investigations on factors orchestrating macrophage polarization in the TME, how macrophage polarization affects tumor progression, and the perspectives in modulating macrophage polarization for cancer immunotherapy.

Cancer stem cells: advances in knowledge and implications for cancer therapy

Cancer stem cells (CSCs), a small subset of cells in tumors that are characterized by self-renewal and continuous proliferation, lead to tumorigenesis, metastasis, and maintain tumor heterogeneity. Cancer continues to be a significant global disease burden. In the past, surgery, radiotherapy, and chemotherapy were the main cancer treatments. The technology of cancer treatments continues to develop and advance, and the emergence of targeted therapy, and immunotherapy provides more options for patients to a certain extent. However, the limitations of efficacy and treatment resistance are still inevitable. Our review begins with a brief introduction of the historical discoveries, original hypotheses, and pathways that regulate CSCs, such as WNT/β-Catenin, hedgehog, Notch, NF-κB, JAK/STAT, TGF-β, PI3K/AKT, PPAR pathway, and their crosstalk. We focus on the role of CSCs in various therapeutic outcomes and resistance, including how the treatments affect the content of CSCs and the alteration of related molecules, CSCs-mediated therapeutic resistance, and the clinical value of targeting CSCs in patients with refractory, progressed or advanced tumors. In summary, CSCs affect therapeutic efficacy, and the treatment method of targeting CSCs is still difficult to determine. Clarifying regulatory mechanisms and targeting biomarkers of CSCs is currently the mainstream idea.

P4HA2 promotes proliferation, invasion, and metastasis through regulation of the PI3K/AKT signaling pathway in oral squamous cell carcinoma

Proline 4-hydroxylase 2 (P4HA2) is known for its hydroxylase activity, primarily involved in hydroxylating collagen precursors and promoting collagen cross-linking under physiological conditions. Although its overexpression influences a wide variety of malignant tumors' occurrence and development, its specific effects and mechanisms in oral squamous cell carcinoma (OSCC) remain unclear. This study focused on investigating the expression patterns, carcinogenic functions, and underlying mechanisms of P4HA2 in OSCC cells. Various databases, including TCGA, TIMER, UALCAN, GEPIA, and K-M plotter, along with paraffin-embedded samples, were used to ascertain P4HA2 expression in cancer and its correlation with clinicopathological features. P4HA2 knockdown and overexpression cell models were developed to assess its oncogenic roles and mechanisms. The results indicated that P4HA2 was overexpressed in OSCC and inversely correlated with patient survival. Knockdown of P4HA2 suppressed invasion, migration, and proliferation of OSCC cells both in vitro and in vivo, whereas overexpression of P4HA2 had the opposite effects. Mechanistically, the phosphorylation levels of the PI3K/AKT pathway were reduced following P4HA2 silencing. The study reveals that P4HA2 acts as a promising biomarker for predicting prognosis in OSCC and significantly affects metastasis, invasion, and proliferation of OSCC cells through the regulation of the PI3K/AKT signaling pathway.

Guanylate binding protein 5 is an immune-related biomarker of oral squamous cell carcinoma: A retrospective prognostic study with bioinformatic analysis

BACKGROUND

Cancer utilizes immunosuppressive mechanisms to create a tumor microenvironment favorable for its progression. The purpose of this study is to histologically characterize the immunological properties of the tumor microenvironment of oral squamous cell carcinoma (OSCC) and identify key molecules involved in the immunological microenvironment and patient prognosis.

METHODS

First, overlapping differentially expressed genes (DEGs) were screened from OSCC transcriptome data in public databases. Correlation analysis of DEGs with known immune-related genes identified genes involved in the immune microenvironment of OSCC. Next, stromal patterns of tumor were classified and immunohistochemical staining was performed for immune cell markers (CD3, CD4, Foxp3, CD8, CD20, CD68, and CD163), programmed death-ligand 1 (PD-L1), and guanylate binding protein 5 (GBP5) in resected specimens obtained from 110 patients with OSCC who underwent resection. Correlations between each factor and their prognostic impact were analyzed.

RESULTS

Among the novel OSCC-specific immune-related genes screened (including ADAMDEC1, CXCL9, CXCL13, DPT, GBP5, IDO1, and PLA2G7), GBP5 was selected as the target gene. Histopathologic analysis showed that multiple T-cell subsets and CD20-positive cells were less common in the advanced stages, whereas CD163-positive cells were more common in advanced stages. The immature type in the stromal pattern category was associated with less immune cell infiltration, lower expression of PD-L1 in immune cells, lower expression of GBP5 in the stroma, and shorter overall survival and recurrence-free survival. Expression of GBP5 in the tumor and stroma correlated with immune cell infiltration of tumors and PD-L1 expression in tumor and immune cells. Patients with low tumor GBP5 expression and high stromal expression had significantly longer overall survival and recurrence-free survival.

CONCLUSIONS

The stromal pattern category may reflect both invasive and immunomodulatory potentials of cancer-associated fibroblasts in OSCC. GBP5 has been suggested as a potential biomarker to predict the prognosis and therapeutic efficacy of immune checkpoint inhibitors.

Pexidartinib and Immune Checkpoint Inhibitors Combine to Activate Tumor Immunity in a Murine Colorectal Cancer Model by Depleting M2 Macrophages Differentiated by Cancer-Associated Fibroblasts

Tumor-associated macrophages (TAMs) and cancer-associated fibroblasts (CAFs) are known to play supportive roles in tumor development and progression, but their interactions in colorectal cancer (CRC) remain unclear. Here, we investigated the effects of colon-cancer-derived CAFs on TAM differentiation, migration, and tumor immunity, both in vitro and in vivo. When co-cultured with monocytes, CAFs attracted monocytes and induced their differentiation into M2 macrophages. Immunohistology of surgically resected human CRC specimens and orthotopically transplanted mouse tumors revealed a correlation between numbers of CAFs and numbers of M2 macrophages. In a mouse model of CRC orthotopic transplantation, treatment with an inhibitor of the colony-stimulating factor-1 receptor (PLX3397) depleted M2 macrophages and increased CD8-positive T cells infiltrating the tumor nest. While this treatment had a minor effect on tumor growth, combining PLX3397 with anti-PD-1 antibody significantly reduced tumor growth. RNA-seq following combination therapy showed activation of tumor immunity. In summary, CAFs are involved in the induction and mobilization of M2 macrophage differentiation in the CRC tumor immune microenvironment, and the combination of cancer immunotherapy and PLX3397 may represent a novel therapeutic option for CRC.

Prognostic and therapeutic potential of senescent stromal fibroblasts in prostate cancer

The stromal component of the tumour microenvironment in primary and metastatic prostate cancer can influence and promote disease progression. Within the prostatic stroma, fibroblasts are one of the most prevalent cell types associated with precancerous and cancerous lesions; they have a vital role in the structural composition, organization and integrity of the extracellular matrix. Fibroblasts within the tumour microenvironment can undergo cellular senescence, which is a stable arrest of cell growth and a phenomenon that is emerging as a recognized hallmark of cancer. Supporting the idea that cellular senescence has a pro-tumorigenic role, a subset of senescent cells exhibits a senescence-associated secretory phenotype (SASP), which, along with increased inflammation, can promote prostate cancer cell growth and survival. These cellular characteristics make targeting senescent cells and/or modulating SASP attractive as a potential preventive or therapeutic option for prostate cancer.

From complexity to clarity: unravelling tumor heterogeneity through the lens of tumor microenvironment for innovative cancer therapy

Despite the tremendous clinical successes recorded in the landscape of cancer therapy, tumor heterogeneity remains a formidable challenge to successful cancer treatment. In recent years, the emergence of high-throughput technologies has advanced our understanding of the variables influencing tumor heterogeneity beyond intrinsic tumor characteristics. Emerging knowledge shows that drivers of tumor heterogeneity are not only intrinsic to cancer cells but can also emanate from their microenvironment, which significantly favors tumor progression and impairs therapeutic response. Although much has been explored to understand the fundamentals of the influence of innate tumor factors on cancer diversity, the roles of the tumor microenvironment (TME) are often undervalued. It is therefore imperative that a clear understanding of the interactions between the TME and other tumor intrinsic factors underlying the plastic molecular behaviors of cancers be identified to develop patient-specific treatment strategies. This review highlights the roles of the TME as an emerging factor in tumor heterogeneity. More particularly, we discuss the role of the TME in the context of tumor heterogeneity and explore the cutting-edge diagnostic and therapeutic approaches that could be used to resolve this recurring clinical conundrum. We conclude by speculating on exciting research questions that can advance our understanding of tumor heterogeneity with the goal of developing customized therapeutic solutions.

Nanomedicines for reversing immunosuppressive microenvironment of hepatocellular carcinoma

Although immunotherapeutic strategies such as immune checkpoint inhibitors (ICIs) have gained promising advances, their limited efficacy and significant toxicity remain great challenges for hepatocellular carcinoma (HCC) immunotherapy. The tumor immunosuppressive microenvironment (TIME) with insufficient T-cell infiltration and low immunogenicity accounts for most HCC patients' poor response to ICIs. Worse still, the current immunotherapeutics without precise delivery may elicit enormous autoimmune side effects and systemic toxicity in the clinic. With a better understanding of the TIME in HCC, nanomedicines have emerged as an efficient strategy to achieve remodeling of the TIME and superadditive antitumor effects via targeted delivery of immunotherapeutics or multimodal synergistic therapy. Based on the typical characteristics of the TIME in HCC, this review summarizes the recent advancements in nanomedicine-based strategies for TIME-reversing HCC treatment. Additionally, perspectives on the awaiting challenges and opportunities of nanomedicines in modulating the TIME of HCC are presented. Acquisition of knowledge of nanomedicine-mediated TIME reversal will provide researchers with a better opportunity for clinical translation of HCC immunotherapy.

Dynamic interactions in the tumor niche: how the cross-talk between CAFs and the tumor microenvironment impacts resistance to therapy

The tumor microenvironment (TME) is a complex ecosystem of cells, signaling molecules, and extracellular matrix components that profoundly influence cancer progression. Among the key players in the TME, cancer-associated fibroblasts (CAFs) have gained increasing attention for their diverse and influential roles. CAFs are activated fibroblasts found abundantly within the TME of various cancer types. CAFs contribute significantly to tumor progression by promoting angiogenesis, remodeling the extracellular matrix, and modulating immune cell infiltration. In order to influence the microenvironment, CAFs engage in cross-talk with immune cells, cancer cells, and other stromal components through paracrine signaling and direct cell-cell interactions. This cross-talk can result in immunosuppression, tumor cell proliferation, and epithelial-mesenchymal transition, contributing to disease progression. Emerging evidence suggests that CAFs play a crucial role in therapy resistance, including resistance to chemotherapy and radiotherapy. CAFs can modulate the tumor response to treatment by secreting factors that promote drug efflux, enhance DNA repair mechanisms, and suppress apoptosis pathways. This paper aims to understand the multifaceted functions of CAFs within the TME, discusses cross-talk between CAFs with other TME cells, and sheds light on the contibution of CAFs to therapy resistance. Targeting CAFs or disrupting their cross-talk with other cells holds promise for overcoming drug resistance and improving the treatment efficacy of various cancer types.

Targeting M2-like tumor-associated macrophages is a potential therapeutic approach to overcome antitumor drug resistance

Tumor drug resistance emerges from the interaction of two critical factors: tumor cellular heterogeneity and the immunosuppressive nature of the tumor microenvironment (TME). Tumor-associated macrophages (TAMs) constitute essential components of the TME. M2-like TAMs are essential in facilitating tumor metastasis as well as augmenting the drug resistance of tumors. This review encapsulates the mechanisms that M2-like TAMs use to promote tumor drug resistance. We also describe the emerging therapeutic strategies that are currently targeting M2-like TAMs in combination with other antitumor drugs, with some still undergoing clinical trial evaluation. Furthermore, we summarize and analyze various existing approaches for developing novel drugs that target M2-like TAMs to overcome tumor resistance, highlighting how targeting M2-like TAMs can effectively stop tumor growth, metastasis, and overcome tumor drug resistance.

Macrophage heterogeneity and its interactions with stromal cells in tumour microenvironment

Macrophages and tumour stroma cells account for the main cellular components in the tumour microenvironment (TME). Current advancements in single-cell analysis have revolutionized our understanding of macrophage diversity and macrophage-stroma interactions. Accordingly, this review describes new insight into tumour-associated macrophage (TAM) heterogeneity in terms of tumour type, phenotype, metabolism, and spatial distribution and presents the association between these factors and TAM functional states. Meanwhile, we focus on the immunomodulatory feature of TAMs and highlight the tumour-promoting effect of macrophage-tumour stroma interactions in the immunosuppressive TME. Finally, we summarize recent studies investigating macrophage-targeted therapy and discuss their therapeutic potential in improving immunotherapy by alleviating immunosuppression.

Reciprocal relationship between cancer stem cells and myeloid-derived suppressor cells: implications for tumor progression and therapeutic strategies

Recently, there has been an increased focus on cancer stem cells (CSCs) due to their resilience, making them difficult to eradicate. This resilience often leads to tumor recurrence and metastasis. CSCs adeptly manipulate their surroundings to create an environment conducive to their survival. In this environment, myeloid-derived suppressor cells (MDSCs) play a crucial role in promoting epithelial-mesenchymal transition and bolstering CSCs' stemness. In response, CSCs attract MDSCs, enhancing their infiltration, expansion and immunosuppressive capabilities. This interaction between CSCs and MDSCs increases the difficulty of antitumor therapy. In this paper, we discuss the interplay between CSCs and MDSCs based on current research and highlight recent therapeutic strategies targeting either CSCs or MDSCs that show promise in achieving effective antitumor outcomes.

The cellular triumvirate: fibroblasts entangled in the crosstalk between cancer cells and immune cells

This review article will focus on subpopulations of fibroblasts that get reprogrammed by tumor cells into cancer-associated fibroblasts. Throughout this article, we will discuss the intricate interactions between fibroblasts, immune cells, and tumor cells. Unravelling complex intercellular crosstalk will pave the way for new insights into cellular mechanisms underlying the reprogramming of the local tumor immune microenvironment and propose novel immunotherapy strategies that might have potential in harnessing and modulating immune system responses.

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

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

Targeting anticancer immunity in oral cancer: Drugs, products, and nanoparticles

Oral cavity carcinomas are the most frequent malignancies among head and neck malignancies. Oral tumors include not only oral cancer cells with different potency and stemness but also consist of diverse cells, containing anticancer immune cells, stromal and also immunosuppressive cells that influence the immune system reactions. The infiltrated T and natural killer (NK) cells are the substantial tumor-suppressive immune compartments in the tumor. The infiltration of these cells has substantial impacts on the response of tumors to immunotherapy, chemotherapy, and radiotherapy. Nevertheless, cancer cells, stromal cells, and some other compartments like regulatory T cells (Tregs), macrophages, and myeloid-derived suppressor cells (MDSCs) can repress the immune responses against malignant cells. Boosting anticancer immunity by inducing the immune system or repressing the tumor-promoting cells is one of the intriguing approaches for the eradication of malignant cells such as oral cancers. This review aims to concentrate on the secretions and interactions in the oral tumor immune microenvironment. We review targeting tumor stroma, immune system and immunosuppressive interactions in oral tumors. This review will also focus on therapeutic targets and therapeutic agents such as nanoparticles and products with anti-tumor potency that can boost anticancer immunity in oral tumors. We also explain possible future perspectives including delivery of various cells, natural products and drugs by nanoparticles for boosting anticancer immunity in oral tumors.

Lactic acid-induced M2-like macrophages facilitate tumor cell migration and invasion via the GPNMB/CD44 axis in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most prevalent form of oral and maxillofacial malignancies, characterized by a low five-year survival rate primarily caused by invasion and metastasis. The progression of OSCC is influenced by macrophage-mediated immunosuppression, which contributes to both local invasion and distant metastasis. Herein, it is of great necessity to explore the molecular mechanisms underlying the crosstalk between OSCC cells and macrophages, as it remains unclear. In the present study, we found that lactic acid orchestrated intracellular communication in the tumor microenvironment. Glycoprotein non-metastatic protein B (GPNMB), a remarkable molecule preferentially expressed by tumor-associated macrophages (TAMs), was significantly highly expressed in the OSCC tissue. The results showed that lactic acid induced macrophage polarization towards an M2-like phenotype and orchestrated GPNMB secretion from macrophages. Furthermore, paracrine GPNMB played a critical role in triggering tumor-promoting activities such as facilitating tumor cell migration, invasion, and epithelial-mesenchymal transition (EMT). In terms of molecular mechanism, GPNMB functionally interacted with the CD44 receptor, and then partially activated the PI3K/AKT/mTOR signaling cascade. Silencing of CD44 could attenuate the tumor-promoting effects of GPNMB in OSCC cells. Collectively, our findings decipher a positive feedback loop in which tumor cells metabolically interact with macrophages in the OSCC microenvironment, highlighting the potential for therapeutic targeting of the GPNMB/CD44 axis as a promising strategy for treating OSCC.

Regulation and signaling pathways in cancer stem cells: implications for targeted therapy for cancer

Cancer stem cells (CSCs), initially identified in leukemia in 1994, constitute a distinct subset of tumor cells characterized by surface markers such as CD133, CD44, and ALDH. Their behavior is regulated through a complex interplay of networks, including transcriptional, post-transcriptional, epigenetic, tumor microenvironment (TME), and epithelial-mesenchymal transition (EMT) factors. Numerous signaling pathways were found to be involved in the regulatory network of CSCs. The maintenance of CSC characteristics plays a pivotal role in driving CSC-associated tumor metastasis and conferring resistance to therapy. Consequently, CSCs have emerged as promising targets in cancer treatment. To date, researchers have developed several anticancer agents tailored to specifically target CSCs, with some of these treatment strategies currently undergoing preclinical or clinical trials. In this review, we outline the origin and biological characteristics of CSCs, explore the regulatory networks governing CSCs, discuss the signaling pathways implicated in these networks, and investigate the influential factors contributing to therapy resistance in CSCs. Finally, we offer insights into preclinical and clinical agents designed to eliminate CSCs.

A novel STAT3/ NFκB p50 axis regulates stromal-KDM2A to promote M2 macrophage-mediated chemoresistance in breast cancer

BACKGROUND

Lysine Demethylase 2A (KDM2A) plays a crucial role in cancer cell growth, differentiation, metastasis, and the maintenance of cancer stemness. Our previous study found that cancer-secreted IL-6 can upregulate the expression of KDM2A to promote further the transition of cells into cancer-associated fibroblasts (CAFs). However, the molecular mechanism by which breast cancer-secreted IL-6 regulates the expression of KDM2A remains unclear. Therefore, this study aimed to elucidate the underlying molecular mechanism of IL-6 in regulating KDM2A expression in CAFs and KDM2A-mediated paclitaxel resistance in breast cancer.

METHODS

The ectopic vector expression and biochemical inhibitor were used to analyze the KDM2A expression regulated by HS-578 T conditioned medium or IL-6 in mammary fibroblasts. Immunoprecipitation and chromatin immunoprecipitation assays were conducted to examine the interaction between STAT3 and NFκB p50. M2 macrophage polarization was assessed by analyzing M2 macrophage-specific markers using flow cytometry and RT-PCR. ESTIMATE algorithm was used to analyze the tumor microenvironment-dominant breast cancer samples from the TCGA database. The correlation between stromal KDM2A and CD163 + M2 macrophages was analyzed using the Pearson correlation coefficient. Cell viability was determined using trypan blue exclusion assay.

RESULTS

IL-6 regulates gene expression via activation and dimerization of STAT3 or collaboration of STAT3 and NFκB. However, STAT3, a downstream transcription factor of the IL-6 signaling pathway, was directly complexed with NFκB p50, not NFκB p65, to upregulate the expression of KDM2A in CAFs. Enrichment analysis of immune cells/stromal cells using TCGA-breast cancer RNA-seq data unveiled a positive correlation between stromal KDM2A and the abundance of M2 macrophages. CXCR2-associated chemokines secreted by KDM2A-expressing CAFs stimulated M2 macrophage polarization, which in turn secreted CCL2 to increase paclitaxel resistance in breast cancer cells by activating CCR2 signaling.

CONCLUSION

This study revealed the non-canonical molecular mechanism of IL-6 secreted by breast cancer upregulated KDM2A expression in CAFs via a novel STAT3/NFκB p50 axis, which STAT3 complexed with NFκB p50 in NFκB p50 binding motif of KDM2A promoter. KDM2A-expressing CAFs dominantly secreted the CXCR2-associated chemokines to promote M2 macrophage polarization and enhance paclitaxel resistance in breast cancer. These findings underscore the therapeutic potential of targeting the CXCR2 or CCR2 pathway as a novel strategy for paclitaxel-resistant breast cancer.

The prognostic value of COX-2 in predicting metastasis of patients with colorectal cancer: A systematic review and meta analysis

Introduction

COX-2 is overexpressed in colorectal tumour tissue relative to the healthy colonic mucosa, thus we investigated the prognostic significance of COX-2 in determining the metastasis of patients with colorectal cancer.

Methods

PubMed, EMBASE, and Cochrane Library were searched using the following terms colorectal cancer, colon cancer, rectal cancer, colorectal carcinoma, Cyclooxygenase-2, and prognosis to identify articles providing information on the prognostic importance of COX-2 in adult patients with metastatic colorectal cancer. Review papers, non-research letters, comments, case reports, animal studies, original research with sample sizes of fewer than 20, case reports and series, non-English language articles, and pediatric studies (those under the age of 17) were excluded. The Newcastle Ottawa Scale (NOS) was used to assess the credibility of the included studies. The full texts were evaluated and this study complied with the terms of the local protocol and the Helsinki Declaration.

Results

Eight relevant studies were included in this review involving 937 patients. The meta-analysis revealed that COX-2 expression is associated with lymph node invasion (RR 1.85 [1.21, 2.83], P = 0.005, I2 = 88 %) and liver metastasis (RR 4.90 [1.12, 21.57], P = 0.04, I2 = 42 %), but not with venous dissemination (RR 1.48 [0.72, 3.03], P = 0.28, I2 = 87 %).

Conclusion

COX-2 expression is associated with lymph node invasion in colorectal cancer but further studies are required to determine the prognostic significance of COX-2 expression in determining metastasis status for colorectal cancer patients.

Involving stemness factors to improve CAR T-cell-based cancer immunotherapy

Treatment with chimeric antigen receptor (CAR) T cells indicated remarkable clinical responses with liquid cancers such as hematological malignancies; however, their therapeutic efficacy faced with many challenges in solid tumors due to severe toxicities, antigen evasion, restricted and limited tumor tissue trafficking and infiltration, and, more importantly, immunosuppressive tumor microenvironment (TME) factors that impair the CAR T-cell function adds support survival of cancer stem cells (CSCs), responsible for tumor recurrence and resistance to current cancer therapies. Therefore, in-depth identification of TME and development of more potent CAR platform targeting CSCs may overcome the raised challenges, as presented in this review. We also discuss recent stemness-based innovations in CAR T-cell production and engineering to improve their efficacy in vivo, and finally, we propose solutions and strategies such as oncolytic virus-based therapy and combination therapy to revive the function of CAR T-cell therapy, especially in TME of solid tumors in future.

ESRRB Inhibits the TGFβ Signaling Pathway to Drive Cell Proliferation in Cervical Cancer

Estrogen-related receptor β (ESRRB) is a member of the orphan nuclear receptor family and mediates stem cell self-renewal and early embryonic development. Previous studies have also reported that ESRRB plays a role in the development and progression of breast cancer and prostate cancer. In this study, we observed that ESRRB was highly expressed in cervical cancer and was associated with disease progression. Knocking out ESRRB using CRISPR/Cas9 gene editing in cervical cancer cells induced cell-cycle arrest at the transition from the G0-G1 phase to the S phase, resulting in inhibition of cell proliferation in vitro and reduced tumor growth in vivo. Conversely, ectopic expression of ESRRB significantly promoted the proliferation of cervical cancer cells. ESRRB activated transcription of SMAD7, a TGFβ pathway inhibitor, which blocked phosphorylation and nuclear translocation of SMAD2/3 to the nucleus, thereby downregulating CDKN1A and upregulating CCNA2 and MYC. In turn, MYC transactivated ESRRB and upregulated SMAD7, thus forming a positive feedback loop with ESRRB. Together, these findings identify the tumor-promoting function of ESRRB in cervical cancer and reveal a mechanism by which ESRRB stimulates cell proliferation to promote cancer progression.

SIGNIFICANCE

The ESRRB/SMAD7/MYC-positive feedback loop inhibits TGFβ signaling to activate cell-cycle progression and promote proliferation in cervical cancer, thereby driving tumor growth.

Role of chemokines in the crosstalk between tumor and tumor-associated macrophages

Tumor microenvironment (TME) consists of a dynamic network of non-tumoral stromal cells, including cancer-associated fibroblasts, endothelial cells, tumor-associated macrophages (TAMs), B and T cells. In the TME, TAMs support tumor initiation, progression, invasion and metastasis by promoting angiogenesis and immunosuppression of the tumor cells. There is close crosstalk between TAMs and tumor cells. Notably, chemokines are a significant messenger mediating the crosstalk between tumor cells and TAMs. TAMs can promote tumor progression via secretion of chemokines. Various chemokines secreted by tumors are involved in the generation and polarization of TAMs, the infiltration of TAMs in tumors, and the development of TAMs' suppressive function. This paper reviews CCL2-CCR2, CCL3/5-CCR5, CCL15-CCR1, CCL18-CCR8, CX3CL1/CCL26-CX3CR1, CXCL8-CXCR1/2, CXCL12-CXCR4/CXCR7 signaling pathways, their role in the recruitment, polarization and exertion of TAMs, and their correlation with tumor development, metastasis and prognosis. Furthermore, we present the current research progress on modulating the effects of TAMs with chemokine antagonists and discuss the prospects and potential challenges of using chemokine antagonists as therapeutic tools for cancer treatment. The TAMs targeting by chemokine receptor antagonists in combination with chemotherapy drugs, immune checkpoint inhibitors or radiotherapy appears to be a promising approach.

The Three-Dimensional In Vitro Cell Culture Models in the Study of Oral Cancer Immune Microenvironment

The onset and progression of oral cancer are accompanied by a dynamic interaction with the host immune system, and the immune cells within the tumor microenvironment play a pivotal role in the development of the tumor. By exploring the cellular immunity of oral cancer, we can gain insight into the contribution of both tumor cells and immune cells to tumorigenesis. This understanding is crucial for developing effective immunotherapeutic strategies to combat oral cancer. Studies of cancer immunology present unique challenges in terms of modeling due to the extraordinary complexity of the immune system. With its multitude of cellular components, each with distinct subtypes and various activation states, the immune system interacts with cancer cells and other components of the tumor, ultimately shaping the course of the disease. Conventional two-dimensional (2D) culture methods fall short of capturing these intricate cellular interactions. Mouse models enable us to learn about tumor biology in complicated and dynamic physiological systems but have limitations as the murine immune system differs significantly from that of humans. In light of these challenges, three-dimensional (3D) culture systems offer an alternative approach to studying cancer immunology and filling the existing gaps in available models. These 3D culture models provide a means to investigate complex cellular interactions that are difficult to replicate in 2D cultures. The direct study of the interaction between immune cells and cancer cells of human origin offers a more relevant and representative platform compared to mouse models, enabling advancements in our understanding of cancer immunology. This review explores commonly used 3D culture models and highlights their significant contributions to expanding our knowledge of cancer immunology. By harnessing the power of 3D culture systems, we can unlock new insights that pave the way for improved strategies in the battle against oral cancer.

Overexpression of RAB27A in Oral Squamous Cell Carcinoma Promotes Tumor Migration and Invasion via Modulation of EGFR Membrane Stability

Oral squamous cell carcinoma (OSCC) is the most prevalent subtype of head and neck tumors, highly prone to lymph node metastasis. This study aims to examine the expression pattern of Ras-related protein Rab-27A (RAB27A) and explore its potential implications in OSCC. The expression of RAB27A was assessed through immunohistochemical analysis utilizing tissue microarrays. In vitro experiments were conducted using RAB27A-knockdown cells to investigate its impact on OSCC tumor cells. Additionally, transcriptome sequencing was performed to elucidate potential underlying mechanisms. RAB27A was significantly overexpressed in OSCC, and particularly in metastatic lymph nodes. It was positively correlated with the clinical progression and poor survival prognosis. Silencing RAB27A notably decreased the proliferation, migration, and invasion abilities of OSCC cells in vitro. A Gene Ontology (GO) enrichment analysis indicated a strong association between RAB27A and the epidermal growth factor receptor (EGFR) signaling pathway. Further investigations revealed that RAB27A regulated the palmitoylation of EGFR via zinc finger DHHC-type containing 13 (ZDHHC13). These findings provide insights into OSCC progression and highlight RAB27A as a potential therapeutic target for combating this aggressive cancer.

Biological Effects of New Titanium Surface Coatings Based on Ionic Liquids and HMGB1: A Cellular and Molecular Characterization in Lewis Rats

High Mobility Group Box 1 (HMGB1) is a redox-sensitive molecule that plays dual roles in tissue healing and inflammation. We previously demonstrated that HMGB1 is stable when anchored by a well-characterized imidazolium-based ionic liquid (IonL), which serves as a delivery vehicle for exogenous HMGB1 to the site of injury and prevents denaturation from surface adherence. However, HMGB1 exists in different isoforms [fully reduced HMGB1 (FR), a recombinant version of FR resistant to oxidation (3S), disulfide HMGB1 (DS), and inactive sulfonyl HMGB1(SO)] that have distinct biological functions in health and disease. Thus, the goal of this study was to evaluate the effects of different recombinant HMGB1 isoforms on the host response using a rat subcutaneous implantation model. A total of 12 male Lewis rats (12-15 weeks) were implanted with titanium discs containing different treatments (n = 3/time point; Ti, Ti-IonL, Ti-IonL-DS, Ti-IonL-FR, and Ti-IonL-3S) and assessed at 2 and 14 days. Histological (H&E and Goldner trichrome staining), immunohistochemistry, and molecular analyses (qPCR) of surrounding implant tissues were employed for analysis of inflammatory cells, HMGB1 receptors, and healing markers. Ti-IonL-DS samples resulted in the thickest capsule formation, increased pro-inflammatory, and decreased anti-inflammatory cells, while Ti-IonL-3S samples demonstrated suitable tissue healing similar to uncoated Ti discs, as well as an upregulation of anti-inflammatory cells at 14 days compared to all other treatments. Thus, results from this study demonstrated that Ti-IonL-3S are safe alternatives for Ti biomaterials. Future studies are necessary to investigate the healing potential of Ti-IonL-3S in osseointegration scenarios.

Single-cell and bulk RNA sequencing reveal cancer-associated fibroblast heterogeneity and a prognostic signature in prostate cancer

Cancer-associated fibroblasts (CAFs), the central players in the tumor microenvironment (TME), can promote tumor progression and metastasis via various functions. However, the properties of CAFs in prostate cancer (PCa) have not been fully assessed. Therefore, we aimed to examine the CAF characteristics in PCa and construct a CAF-derived signature to predict PCa prognosis. CAFs were identified using single-cell RNA sequencing (scRNA-seq) data from 3 studies. We performed the FindAllMarkers function to extract CAF marker genes and constructed a signature to predict the biochemical relapse-free survival (bRFS) of PCa in the Cancer Genome Atlas (TCGA) cohort. Subsequently, different algorithms were applied to reveal the differences of the TME, immune infiltration, treatment responses in the high- and low-risk groups. Additionally, the CAF heterogeneity was assessed in PCa, which were confirmed by the functional enrichment analysis, gene set enrichment analysis (GSEA), and AUCell method. The scRNA-seq analysis identified a CAF cluster with 783 cells and determined 183 CAF marker genes. Cell-cell communication revealed extensive interactions between fibroblasts and immune cells. A CAF-related prognostic model, containing 7 genes (ASPN, AEBP1, ALDH1A1, BGN, COL1A1, PAGE4 and RASD1), was developed to predict bRFS and validated by 4 independent bulk RNA-seq cohorts. Moreover, the high-risk group of the signature score connected with an immunosuppressive TME, such as a higher level of M2 macrophages and lower levels of plasma cells and CD8+ T cells, and a reduced reaction rate for immunotherapy compared with low-risk group. After re-clustering CAFs via unsupervised clustering, we revealed 3 biologically distinct CAF subsets, namely myofibroblast-like CAFs (myCAFs), immune and inflammatory CAFs (iCAFs) and antigen-presenting CAFs (apCAFs). In conclusion, the CAF-derived signature, the first of its kind, can effectively predict PCa prognosis and serve as an indicator for immunotherapy. Furthermore, our study identified 3 CAF subpopulations with distinct functions in PCa.

Targeting oral tumor microenvironment for effective therapy

Oral cancers are among the common head and neck malignancies. Different anticancer therapy modalities such as chemotherapy, immunotherapy, radiation therapy, and also targeted molecular therapy may be prescribed for targeting oral malignancies. Traditionally, it has been assumed that targeting malignant cells alone by anticancer modalities such as chemotherapy and radiotherapy suppresses tumor growth. In the last decade, a large number of experiments have confirmed the pivotal role of other cells and secreted molecules in the tumor microenvironment (TME) on tumor progression. Extracellular matrix and immunosuppressive cells such as tumor-associated macrophages, myeloid-derived suppressor cells (MDSCs), cancer-associated fibroblasts (CAFs), and regulatory T cells (Tregs) play key roles in the progression of tumors like oral cancers and resistance to therapy. On the other hand, infiltrated CD4 + and CD8 + T lymphocytes, and natural killer (NK) cells are key anti-tumor cells that suppress the proliferation of malignant cells. Modulation of extracellular matrix and immunosuppressive cells, and also stimulation of anticancer immunity have been suggested to treat oral malignancies more effectively. Furthermore, the administration of some adjuvants or combination therapy modalities may suppress oral malignancies more effectively. In this review, we discuss various interactions between oral cancer cells and TME. Furthermore, we also review the basic mechanisms within oral TME that may cause resistance to therapy. Potential targets and approaches for overcoming the resistance of oral cancers to various anticancer modalities will also be reviewed. The findings for targeting cells and potential therapeutic targets in clinical studies will also be reviewed.

Macrophages in immunoregulation and therapeutics

Macrophages exist in various tissues, several body cavities, and around mucosal surfaces and are a vital part of the innate immune system for host defense against many pathogens and cancers. Macrophages possess binary M1/M2 macrophage polarization settings, which perform a central role in an array of immune tasks via intrinsic signal cascades and, therefore, must be precisely regulated. Many crucial questions about macrophage signaling and immune modulation are yet to be uncovered. In addition, the clinical importance of tumor-associated macrophages is becoming more widely recognized as significant progress has been made in understanding their biology. Moreover, they are an integral part of the tumor microenvironment, playing a part in the regulation of a wide variety of processes including angiogenesis, extracellular matrix transformation, cancer cell proliferation, metastasis, immunosuppression, and resistance to chemotherapeutic and checkpoint blockade immunotherapies. Herein, we discuss immune regulation in macrophage polarization and signaling, mechanical stresses and modulation, metabolic signaling pathways, mitochondrial and transcriptional, and epigenetic regulation. Furthermore, we have broadly extended the understanding of macrophages in extracellular traps and the essential roles of autophagy and aging in regulating macrophage functions. Moreover, we discussed recent advances in macrophages-mediated immune regulation of autoimmune diseases and tumorigenesis. Lastly, we discussed targeted macrophage therapy to portray prospective targets for therapeutic strategies in health and diseases.

Knockdown of HMGB1 inhibits the crosstalk between oral squamous cell carcinoma cells and tumor-associated macrophages

Tumor-associated macrophages (TAMs), the major component of the tumor microenvironment (TME), play distinctly different roles in different tumors. High mobility group box 1 (HMGB1), a nonhistone protein in the nucleus, can perform functions during inflammation and cancers. However, the role of HMGB1 in the crosstalk between oral squamous cell carcinoma (OSCC) cells and TAMs remains unclear. Here, we established a coculture system of TAMs and OSCC cells to explore the bidirectional effect and potential mechanism of HMGB1 in OSCC cell-TAM interactions. Our results showed that HMGB1 was significantly upregulated in OSCC tissues and positively associated with tumor progression, immune cell infiltration and macrophage polarization. Then, knocking down HMGB1 in OSCC cells inhibited the recruitment and polarization of cocultured TAMs. Moreover, the knockdown of HMGB1 in macrophages not only suppressed polarization, but also inhibited cocultured OSCC cell proliferation, migration and invasion in vitro and in vivo. Mechanistically, macrophages secreted higher levels of HMGB1 than OSCC cells, and dampening endogenous HMGB1 reduced HMGB1 secretion. Both OSCC cell-generated and macrophage-endogenous HMGB1 may regulate TAM polarization by promoting receptor TLR4 expression and NF-κB/p65 activation and enhancing IL-10/TGF-β expression. HMGB1 in OSCC cells may regulate macrophage recruitment via IL-6/STAT3. In addition, TAM-derived HMGB1 may affect aggressive phenotypes of cocultured OSCC cells by regulating the immunosuppressive microenvironment through the IL-6/STAT3/PD-L1 and IL-6/NF-κB/MMP-9 pathways. In conclusion, HMGB1 may regulate the crosstalk between OSCC cells and TAMs, including modulating macrophage polarization and attraction, enhancing cytokine secretion, and remodeling and creating an immunosuppressive TME to further affect OSCC progression.

Dissecting the functions of cancer-associated fibroblasts to therapeutically target head and neck cancer microenvironment

Head and neck cancers (HNC) are a diverse group of aggressive malignancies with high morbidity and mortality, leading to almost half-million deaths annually worldwide. A better understanding of the molecular processes governing tumor formation and progression is crucial to improve current diagnostic and prognostic tools as well as to develop more personalized treatment strategies. Tumors are highly complex and heterogeneous structures in which growth and dissemination is not only governed by the cancer cells intrinsic mechanisms, but also by the surrounding tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) emerge as predominant TME components and key players in the generation of permissive conditions that ultimately impact in tumor progression and metastatic dissemination. Although CAFs were initially considered a consequence of tumor development, it is now well established that they actively contribute to numerous cancer hallmarks i.e., tumor cell growth, migration and invasion, cancer cell stemness, angiogenesis, metabolic reprograming, inflammation, and immune system modulation. In this scenario, therapeutic strategies targeting CAF functions could potentially have a major impact in cancer therapeutics, providing avenues for new treatment options or for improving efficacy in established approaches. This review is focused on thoroughly dissecting existing evidences supporting the contribution of CAFs in HNC biology with an emphasis on current knowledge of the key molecules and pathways involved in CAF-tumor crosstalk, and their potential as novel biomarkers and/or therapeutic targets to effectively interfere the tumor-stroma crosstalk for HNC patients benefit. involved in CAF-tumor crosstalk, and their potential as novel biomarkers and/or therapeutic targets to effec- tively interfere the tumor-stroma crosstalk for HNC patients benefit.

Regulatory Effects of Three-Dimensional Cultured Lipopolysaccharide-Pretreated Periodontal Ligament Stem Cell-Derived Secretome on Macrophages

Phenotypic transformation of macrophages plays important immune response roles in the occurrence, development and regression of periodontitis. Under inflammation or other environmental stimulation, mesenchymal stem cells (MSCs) exert immunomodulatory effects through their secretome. It has been found that secretome derived from lipopolysaccharide (LPS)-pretreated or three-dimensional (3D)-cultured MSCs significantly reduced inflammatory responses in inflammatory diseases, including periodontitis, by inducing M2 macrophage polarization. In this study, periodontal ligament stem cells (PDLSCs) pretreated with LPS were 3D cultured in hydrogel (termed SupraGel) for a certain period of time and the secretome was collected to explore its regulatory effects on macrophages. Expression changes of immune cytokines in the secretome were also examined to speculate on the regulatory mechanisms in macrophages. The results indicated that PDLSCs showed good viability in SupraGel and could be separated from the gel by adding PBS and centrifuging. The secretome derived from LPS-pretreated and/or 3D-cultured PDLSCs all inhibited the polarization of M1 macrophages, while the secretome derived from LPS-pretreated PDLSCs (regardless of 3D culture) had the ability to promote the polarization of M1 to M2 macrophages and the migration of macrophages. Cytokines involved in the production, migration and polarization of macrophages, as well as multiple growth factors, increased in the PDLSC-derived secretome after LPS pretreatment and/or 3D culture, which suggested that the secretome had the potential to regulate macrophages and promote tissue regeneration, and that it could be used in the treatment of inflammation-related diseases such as periodontitis in the future.

The tumor ecosystem in head and neck squamous cell carcinoma and advances in ecotherapy

The development of head and neck squamous cell carcinoma (HNSCC) is a multi-step process, and its survival depends on a complex tumor ecosystem, which not only promotes tumor growth but also helps to protect tumor cells from immune surveillance. With the advances of existing technologies and emerging models for ecosystem research, the evidence for cell-cell interplay is increasing. Herein, we discuss the recent advances in understanding the interaction between tumor cells, the major components of the HNSCC tumor ecosystem, and summarize the mechanisms of how biological and abiotic factors affect the tumor ecosystem. In addition, we review the emerging ecological treatment strategy for HNSCC based on existing studies.

Comprehensive analysis of the immunological implication and prognostic value of CXCR4 in non-small cell lung cancer

CXCR4 (C-X-C chemokine receptor type 4) is the most commonly expressed of all chemokine receptors in malignant tumors. However, studies on CXCR4 in non-small cell lung cancer (NSCLC) tumor immune microenvironment, including those determining its immune efficacy and prognostic potential, are still scarce. Therefore, in this study, we determined the ability of CXCR4 to predict immunotherapy response and prognosis in NSCLC using immunohistochemical staining and RT-PCR, respectively, in two independent cohorts from the National Cancer Center of China. We analyzed transcriptome sequencing data and clinical information from multiple public databases to assess immune cell infiltration in NSCLC and constructed immune risk prognostic signatures based on CXCR4-related immunomodulators. We found that immune cell infiltration is significant differences in NSCLC tissues and is moderately correlated with CXCR4 expression. High CXCR4 expression was significantly associated with poor prognosis in NSCLC patients and a higher response rate to immunotherapy. The ROC curve showed that CXCR4 expression exhibited excellent performance in predicting the efficacy of immunotherapy in NSCLC. We identified 30 CXCR4-related immunomodulators in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) and constructed immune prognostic signatures based on CXCR4-related immunomodulators and CXCR4-related mutant genes. The signature-based prognostic risk score showed good performance in predicting patient prognosis in both LUAD and LUSC; high risk scores were significantly associated with poor prognosis (P < 0.0001) and was established as an independent prognostic factor by multivariate Cox regression. We postulate that CXCR4 is a potential predictive marker of immunotherapy efficacy in NSCLC and should be used in clinical settings. Moreover, the constructed signatures may be valuable in predicting patient prognosis in NSCLC.

CAFs orchestrates tumor immune microenvironment—A new target in cancer therapy?

Cancer immunotherapy has opened a new landscape in cancer treatment, however, the poor specificity and resistance of most targeted therapeutics have limited their therapeutic efficacy. In recent years, the role of CAFs in immune regulation has been increasingly noted as more evidence has been uncovered regarding the link between cancer-associated fibroblasts (CAFs) and the evolutionary process of tumor progression. CAFs interact with immune cells to shape the tumor immune microenvironment (TIME) that favors malignant tumor progression, a crosstalk process that leads to the failure of cancer immunotherapies. In this review, we outline recent advances in the immunosuppressive function of CAFs, highlight the mechanisms of CAFs-immune cell interactions, and discuss current CAF-targeted therapeutic strategies for future study.