Spatial and Quantitative Analysis of Tumor-Associated Macrophages: Intratumoral CD163-/PD-L1+ TAMs as a Marker of Favorable Clinical Outcomes in Triple-Negative Breast Cancer.

Tumor-associated macrophages (TAMs) and abnormalities in cancer cells affect cancer progression and response to therapy. TAMs are a major component of the tumor microenvironment (TME) in breast cancer, with their invasion affecting clinical outcomes. Programmed death-ligand 1 (PD-L1), a target of immune checkpoint inhibitors, acts as a suppressive signal for the surrounding immune system; however, its expression and effect on TAMs and the clinical outcome in breast cancer are unknown. In this study, we used high-throughput multiple immunohistochemistry to spatially and quantitatively analyze TAMs. We subjected 81 breast cancer specimens to immunostaining for CD68, CD163, PD-1, PD-L1, CD20, and pan-CK. In both stromal and intratumoral areas, the triple-negative subtype had significantly more CD68/CD163, CD68/PD-L1, and CD163/PD-L1 double-positive cells than the estrogen receptor (ER)/progesterone receptor (PR) subtype. Interestingly, a higher number of CD68+/PD-L1+/CK-/CD163- TAMs in the intratumoral area was correlated with a favorable recurrence rate (p = 0.048). These findings indicated that the specific subpopulation and localization of TAMs in the TME affect clinical outcomes in breast cancer.

Exosome-derived lnc-HOXB8-1:2 induces tumor-associated macrophage infiltration to promote neuroendocrine differentiated colorectal cancer progression by sponging hsa-miR-6825-5p.

INTRODUCTION: Neuroendocrine differentiation (NED) in colorectal cancer (CRC) cells has been known for decades, and our previous meta-analysis indicated that CRC patients with neuroendocrine differentiation have a lower 5-year survival rate. In recent years, an increasing number of studies have found that exosome-derived long non-coding RNAs (lncRNAs) play important roles in cancer progression and metastasis. However, the functions and mechanism of exosome-derived lncRNAs in CRC with neuroendocrine differentiation are not yet fully clear. MATERIALS AND METHODS: The clinical significance of NED was assessed in a retrospective study of 105 patients. Next-generation sequencing and bioinformatics analysis were conducted to select lnc-HOXB8-1:2 for further study. Using immunohistochemistry, qRT-PCR, western blot, transwell assay, immunofluorescence assay, fluorescence in situ hybridization assay and dual-luciferase reporter assay, the oncogenic role of exosome-derived lnc-HOXB8-1:2 was determined in CRC with NED. The mechanism underlying the lnc-HOXB8-1:2/hsa-miR-6825-5p/CXCR3 axis was also explored. RESULTS: NED was a risk factor for the progression and mortality of CRC. lnc-HOXB8-1:2, derived from exosomes secreted by neuroendocrine differentiated colon cancer cells, was identified in our study. The proportion of M2 macrophages and the migration and invasion capacities of tumor-associated macrophages (TAMs) markedly increased after the addition of neuroendocrine differentiated CRC cell-derived exosomes. More excitingly, the expression of lnc-HOXB8-1:2 and the protein level of CXCR3 were also upregulated in TAMs. The lnc-HOXB8-1:2/hsa-miR-6825-5p/CXCR3 axis was predicted via miRanda software and confirmed by the dual-luciferase reporter assay. Furthermore, the increased expression of lnc-HOXB8-1:2 was accompanied by downregulation of hsa-miR-6825-5p expression and upregulation of CXCR3 protein levels. Overexpression of hsa-miR-6825-5p also reduced CXCR3 expression. CONCLUSION: lnc-HOXB8-1:2 in exosomes derived from neuroendocrine differentiated CRC cells acted as a ceRNA competitively binding hsa-miR-6825-5p to upregulate CXCR3 expression and leading to TAM infiltration and M2 polarization, which promotes neuroendocrine differentiated CRC progression.

LINC00665 interacts with BACH1 to activate Wnt1 and mediates the M2 polarization of tumor-associated macrophages in GC.

Gastric cancer (GC) remains one of the prevalent causes of cancer-related deaths globally. Long non-coding RNAs (lncRNAs) have been associated with different cancers. The polarization of macrophages towards the M2 (alternatively activated) phenotype promotes immunologic tolerance and can induce gastric tumorigenesis. Thus far, lncRNAs have been shown to modulate the differentiation of immune cells. Here, we investigated the biological effects of LINC00665 on the progression of GC and explored the mechanisms underlying its ability to mediate the polarization of macrophages towards the M2 phenotype. We report that the levels of LINC00665 were increased in GC tissues. Furthermore, this increase in LINC00665 expression could be associated with decreased overall survival (OS), progression-free survival (PFS), and post-progression survival (PPS). Using cell-based macrophage polarization models, we demonstrated that LINC00665 upregulation in GC cells facilitated the polarization of macrophages towards the M2 but not M1 (classically activated) phenotype. Furthermore, the loss of LINC00665 prevented the M2 polarization of macrophages. Mechanically, we identified that Wnt1 was the downstream target of LINC00665. Additionally, LINC00665 could directly interact with the transcription factor BTB domain and CNC homology 1 (BACH1). The interaction between LINC00665 and BACH1 resulted in the activation and binding of BACH1 to the Wnt1 promoters. Furthermore, BACH1 silencing could inhibit GC progression, which highlighted a crucial role for BACH1 in LINC00665-mediated Wnt1 activation. In addition, genetic Wnt1 overexpression effectively abolished the repression of Wnt signaling after BACH1 depletion and mediated GC development by supporting M2 macrophage polarization. In conclusion, we report that LINC00665 modulates M2 macrophage polarization and suggest that it may facilitate macrophage-dependent GC progression.

Dual-sgRNA CRISPR/Cas9 knockout of PD-L1 in human U87 glioblastoma tumor cells inhibits proliferation, invasion, and tumor-associated macrophage polarization.

Programmed death ligand 1 (PD-L1) plays a key role in glioblastoma multiforme (GBM) immunosuppression, vitality, proliferation, and migration, and is therefore a promising target for treating GBM. CRISPR/Cas9-mediated genomic editing can delete both cell surface and intracellular PD-L1. This systemic deliverable genomic PD-L1 deletion system can be used as an effective anti-GBM therapy by inhibiting tumor growth and migration, and overcoming immunosuppression. To target PD-L1 for CRISPR/Cas9 gene editing, we first identified two single guide RNA (sgRNA) sequences located on PD-L1 exon 3. The first sgRNA recognizes the forward strand of human PD-L1 near the beginning of exon 3 that allows editing by Cas9 at approximately base pair 82 (g82). The second sgRNA recognizes the forward strand of exon 3 that directs cutting at base pair 165 (g165). A homology-directed repair template (HDR) combined with the dual-sgRNAs was used to improve PD-L1 knockout specificity and efficiency. sgRNAs g82 and g165 were cloned into the multiplex CRISPR/Cas9 assembly system and co-transfected with the HDR template in human U87 GBM cells (g82/165 + HDR). T7E1 analysis suggests that the dual-sgRNA CRISPR/Cas9 strategy with a repair template was capable of editing the genomic level of PD-L1. This was further confirmed by examining PD-L1 protein levels by western blot and immunofluorescence assays. Western blot analysis showed that the dual-sgRNAs with the repair template caused a 64% reduction of PD-L1 protein levels in U87 cells, while immunostaining showed a significant reduction of intracellular PD-L1. PD-L1 deletion inhibited proliferation, growth, invasion and migration of U87 cells, indicating intracellular PD-L1 is necessary for tumor progression. Importantly, U87 cells treated with g82/165 + HDR polarized tumor-associated macrophages (TAM) toward an M1 phenotype, as indicated by an increase in TNF-α and a decrease in IL-4 secretions. This was further confirmed with flow cytometry that showed an increase in the M1 markers Ly6C + and CD80 +, and a decrease in the M2 marker CD206 + both in vitro and in vivo. Utilizing dual-sgRNAs and an HDR template with the CRISPR/Cas9 gene-editing system is a promising avenue for the treatment of GBM.

Long non-coding RNA NBR2 suppresses the progress of colorectal cancer in vitro and in vivo by regulating the polarization of TAM.

Colorectal cancer (CRC) threatens the health of patients with high mortality, which lacks sensitive biomarkers for diagnosis to improve total survival. The lncRNA NBR2 is reported to be downregulated in CRC and suppresses the proliferation of CRC cells. However, the underlying mechanisms remain unclear. The present study aimed to explore the regulatory function of the lncRNA NBR2 on tumor-associated macrophage (TAM) polarization and its consequent anti-tumor effect. Two CRC cell lines were used in this study. We found that the lncRNA NBR2, TNF-α, and HLA-DR were downregulated, and Arg-1, CD163, CD206, and IL-4 were upregulated in CRC tumors. M1 polarization was activated and M2 polarization was suppressed in NBR2-overexpressed macrophages, accompanied by increased production of inflammatory factors, decreased proliferation, and inhibited migration ability in the co-culture system of HCT-116 cells (SW480 cells) and NBR2-overexpressed macrophages. The promoted proliferation and migration were observed in the co-culture system of HCT-116 cells (SW480 cells) and NBR2-knockdown macrophages. The tumor growth of both HCT-116 cells and SW480 cells in the xenograft model was suppressed by co-planting NBR2-overexpressed macrophages and was facilitated by the co-planting of NBR2-knockdown macrophages. The release of inflammatory factors was induced, M1 polarization was facilitated, and M2 polarization was suppressed in tumor tissues in the NBR2-overexpressed group, which were all reversed in the NBR2-knockdown group. Therefore, the lncRNA NBR2 suppressed the progression of colorectal cancer in vitro and in vivo by regulating TAM polarization.

Soluble Factors Involved in Cancer Cell-Macrophage Interaction Promote Breast Cancer Growth.

BACKGROUND/AIM: Recent studies have indicated the clinical significance of tumor-associated macrophages (TAMs) in breast cancer; however, the detailed mechanisms of cell-cell interactions between TAMs and cancer cells remain unclear. MATERIALS AND METHODS: In vitro cell culture studies using human monocyte-derived macrophages and breast cancer cell lines were performed to test which cytokines would be involved in cell-cell interactions between cancer cells and macrophages. In addition, studies using human resected samples and animal breast cancer models were performed to examine the significance of TAMs in cancer development. RESULTS: Osteopontin, HB-EGF, and IL-6 were suggested to be macrophage-derived growth factors for breast cancer cells. FROUNT inhibitor significantly blocked TAM infiltration and subcutaneous tumor growth in an E0771 mouse breast cancer model. CONCLUSION: TAMs express growth factors, such as osteopontin, for cancer cells, and targeting of TAM infiltration might be a promising approach for anti-breast cancer therapy.

Relationship between Fusobacterium nucleatum and antitumor immunity in colorectal cancer liver metastasis.

Fusobacterium nucleatum has been detected in 8%-13% of human colorectal cancer, and shown to inhibit immune responses against primary colorectal tumors in animal models. Thus, we hypothesized that the presence of F. nucleatum might be associated with reduced T cell density in colorectal cancer liver metastases (CRLM). We quantified F. nucleatum DNA in 181 CRLM specimens using quantitative PCR assay. The densities of CD8+ T cells, CD33+ cells (marker for myeloid-derived suppressor cells [MDSCs]), and CD163+ cells (marker for tumor-associated macrophages [TAMs]) in CRLM tissue were determined by immunohistochemical staining. Fusobacterium nucleatum was detected in eight (4.4%) of 181 CRLM specimens. Compared with F. nucleatum-negative CRLM, F. nucleatum-positive CRLM showed significantly lower density of CD8+ T cells (P = .033) and higher density of MDSCs (P = .001). The association of F. nucleatum with the density of TAMs was not statistically significant (P = .70). The presence of F. nucleatum is associated with a lower density of CD8+ T cells and a higher density of MDSCs in CRLM tissue. Upon validation, our findings could provide insights to develop strategies that involve targeting microbiota and immune cells for the prevention and treatment of CRLM.

Engineering Endogenous Tumor-Associated Macrophage-Targeted Biomimetic Nano-RBC to Reprogram Tumor Immunosuppressive Microenvironment for Enhanced Chemo-Immunotherapy.

Immunotherapy has shown encouraging results in various cancers, but the response rates are relatively low due to the complex tumor immunosuppressive microenvironment (TIME). The presence of tumor-associated macrophages (TAMs) and tumor hypoxia correlates significantly with potent immunosuppressive activity. Here, a hemoglobin-poly(ε-caprolactone) (Hb-PCL) conjugate self-assembled biomimetic nano red blood cell (nano-RBC) system (V(Hb)) is engineered to deliver chemotherapeutic doxorubicin (DOX) and oxygen for reprogramming TIME. The Hb moiety of V(Hb)@DOX can bind to endogenous plasma haptoglobin (Hp) and specifically target the M2-type TAMs via the CD163 surface receptor, and effectively kill the cells. In addition, the O2 released by the Hb alleviates tumor hypoxia, which further augments the antitumor immune response by recruiting fewer M2-type macrophages. TAM-targeting depletion and hypoxia alleviation synergistically reprogram the TIME, which concurrently downregulate PD-L1 expression of tumor cells, decrease the levels of immunosuppressive cytokines such as IL-10 and TGF-ß, elevate the immunostimulatory IFN-γ, enhance cytotoxic T lymphocyte (CTL) response, and boost a strong memory response. The ensuing TAM-targeted chemo-immunotherapeutic effects markedly inhibit tumor metastasis and recurrence. Taken together, the engineered endogenous TAM-targeted biomimetic nano-RBC system is a highly promising tool to reprogram TIME for cancer chemo-immunotherapy.

Cancer­associated fibroblast­induced M2­polarized macrophages promote hepatocellular carcinoma progression via the plasminogen activator inhibitor­1 pathway.

Targeting the tumor stroma is an important strategy in cancer treatment. Cancer­associated fibroblasts (CAFs) and tumor­associated macrophages (TAMs) are two main components in the tumor microenvironment (TME) in hepatocellular carcinoma (HCC), which can promote tumor progression. Plasminogen activator inhibitor­1 (PAI­1) upregulation in HCC is predictive of unfavorable tumor behavior and prognosis. However, the crosstalk between cancer cells, TAMs and CAFs, and the functions of PAI­1 in HCC remain to be fully investigated. In the present study, macrophage polarization and key paracrine factors were assessed during their interactions with CAFs and cancer cells. Cell proliferation, wound healing and Transwell and Matrigel assays were used to investigate the malignant behavior of HCC cells in vitro. It was found that cancer cells and CAFs induced the M2 polarization of TAMs by upregulating the mRNA expression levels of CD163 and CD206, and downregulating IL­6 mRNA expression and secretion in the macrophages. Both TAMs derived from cancer cells and CAFs promoted HCC cell proliferation and invasion. Furthermore, PAI­1 expression was upregulated in TAMs after being stimulated with CAF­conditioned medium and promoted the malignant behavior of the HCC cells by mediating epithelial­mesenchymal transition. CAFs were the main producer of C­X­C motif chemokine ligand 12 (CXCL12) in the TME and CXCL12 contributed to the induction of PAI­1 secretion in TAMs. In conclusion, the results of the present study suggested that CAFs promoted the M2 polarization of macrophages and induced PAI­1 secretion via CXCL12. Furthermore, it was found that PAI­1 produced by the TAMs enhanced the malignant behavior of the HCC cells. Therefore, these factors may be targets for inhibiting the crosstalk between tumor cells, CAFs and TAMs.

Discovery of RRx-001, a Myc and CD47 Downregulating Small Molecule with Tumor Targeted Cytotoxicity and Healthy Tissue Cytoprotective Properties in Clinical Development.

After extensive screening of aerospace compounds in an effort to source a novel anticancer agent, RRx-001, a first-in-class dinitroazetidine small molecule, was selected for advancement into preclinical and clinical development. RRx-001 is a minimally toxic small molecule with a distinct chemical structure and mechanism of action. The paradox of RRx-001 is that it mediates both antitumor cytotoxicity and normal tissue protection. The question of exactly how RRx-001 does this, and by means of what mechanism(s), depending on the route of delivery, intravenous or intratumoral, are explored. RRx-001 is currently in phase 2 and 3 clinical trials for the treatment of multiple solid tumor malignancies and as a supportive care drug.

Role of tumor-associated macrophages at the invasive front in human colorectal cancer progression.

Macrophages are an essential component of antitumor activity; however, the role of tumor-associated macrophages (TAMs) in colorectal cancer (CRC) remains controversial. Here, we elucidated the role of TAMs in CRC progression, especially at the early stage. We assessed the TAM number, phenotype, and distribution in 53 patients with colorectal neoplasia, including intramucosal neoplasia, submucosal invasive colorectal cancer (SM-CRC), and advanced cancer, using double immunofluorescence for CD68 and CD163. Next, we focused on the invasive front in SM-CRC and association between TAMs and clinicopathological features including lymph node metastasis, which were evaluated in 87 SM-CRC clinical specimens. The number of M2 macrophages increased with tumor progression and dynamic changes were observed with respect to the number and phenotype of TAMs at the invasive front, especially at the stage of submucosal invasion. A high M2 macrophage count at the invasive front was correlated with lymphovascular invasion, low histological differentiation, and lymph node metastasis; a low M1 macrophage count at the invasive front was correlated with lymph node metastasis. Furthermore, receiver operating characteristic curve analysis revealed that the M2/M1 ratio was a better predictor of the risk of lymph node metastasis than the pan-, M1, or M2 macrophage counts at the invasive front. These results suggested that TAMs at the invasive front might play a role in CRC progression, especially at the early stages. Therefore, evaluating the TAM phenotype, number, and distribution may be a potential predictor of metastasis, including lymph node metastasis, and TAMs may be a potential CRC therapeutic target.

Isolation and separation of murine tumor-associated macrophages (TAMs) subpopulations from orthotopic 4T1 breast tumors.

Tumor-associated macrophages (TAMs) are highly heterogenous regarding their intratumoral localization, surface marker expression, and molecular properties. This protocol describes the complete procedure for isolation and digestion of murine breast cancer samples and fluorescence-activated cell sorting (FACS) of TAMs from murine orthotopic 4T1 breast tumors. This includes steps to separate PoEMs (podoplanin-expressing macrophages) and non-PoEMs (podoplanin-negative macrophages). Our FACS separation approach could also be used for other tumor types with TAM infiltration. For complete details on the use and execution of this protocol, please refer to Bieniasz-Krzywiec et al. (2019).

Single-cell profiling of myeloid cells in glioblastoma across species and disease stage reveals macrophage competition and specialization.

Glioblastomas are aggressive primary brain cancers that recur as therapy-resistant tumors. Myeloid cells control glioblastoma malignancy, but their dynamics during disease progression remain poorly understood. Here, we employed single-cell RNA sequencing and CITE-seq to map the glioblastoma immune landscape in mouse tumors and in patients with newly diagnosed disease or recurrence. This revealed a large and diverse myeloid compartment, with dendritic cell and macrophage populations that were conserved across species and dynamic across disease stages. Tumor-associated macrophages (TAMs) consisted of microglia- or monocyte-derived populations, with both exhibiting additional heterogeneity, including subsets with conserved lipid and hypoxic signatures. Microglia- and monocyte-derived TAMs were self-renewing populations that competed for space and could be depleted via CSF1R blockade. Microglia-derived TAMs were predominant in newly diagnosed tumors, but were outnumbered by monocyte-derived TAMs following recurrence, especially in hypoxic tumor environments. Our results unravel the glioblastoma myeloid landscape and provide a framework for future therapeutic interventions.

Mechanism of tumour microenvironment in the progression and development of oral cancer.

Oral cancer has been a major problem all across the globe, majorly in the developing countries. With a growing emphasis in the field of cancer research, the contribution of the tumour microenvironment has been gaining a lot of importance in identifying the role of components other than the tumour cells that cause the development of cancer, thus changing the outlook. The review will shed light on the studies that describe the role of microenvironment, its components as well as summarize the studies related to their mechanism in the progression of oral cancer. The literature for the review was derived mainly from Google Scholar and PubMed, in particular concentrating on the most recent papers published in 2019 and 2020, by using the keywords "Cancer, Oral Cancer, Metastasis, OSCC, Tumour microenvironment, CAFs, ECM, Cytokines, Hypoxia, Therapeutics targeting the microenvironment". The study provides insight into the world of micro-environmental regulation of oral cancer, the mechanism by which they interact and how to exploit it as a potential therapeutic haven for treating the disease. The components Cancer-Associated Fibroblasts (CAFs), Tumour-associated Macrophages (TAMs), Tumour-associated neutrophils (TANs), Hypoxic environment, myeloid-derived stem cells (MDSCs) and T regulatory (Tregs) cells and underlying mechanisms that control them will be the targets of study to understand the microenvironment.

Metabolic crosstalk in the tumor microenvironment regulates antitumor immunosuppression and immunotherapy resisitance.

The successful treatment of human cancers by immunotherapy has been made possible by breakthroughs in the discovery of immune checkpoint regulators, including CTLA-4 and PD-1/PD-L1. However, the immunosuppressive effect of the tumor microenvironment still represents an important bottleneck that limits the success of immunotherapeutic approaches. The tumor microenvironment influences the metabolic crosstalk between tumor cells and tumor-infiltrating immune cells, creating competition for the utilization of nutrients and promoting immunosuppression. In addition, tumor-derived metabolites regulate the activation and effector function of immune cells through a variety of mechanisms; in turn, the metabolites and other factors secreted by immune cells can also become accomplices to cancer development. Immune-metabolic checkpoint regulation is an emerging concept that is being studied with the aim of restoring the immune response in the tumor microenvironment. In this review, we summarize the metabolic reprogramming of various cell types present in the tumor microenvironment, with a focus on the interaction between the metabolic pathways of these cells and antitumor immunosuppression. We also discuss the main metabolic checkpoints that could provide new means of enhancing antitumor immunotherapy.

Tumor microenvironment and Oral Squamous Cell Carcinoma: A crosstalk between the inflammatory state and tumor cell migration.

OBJECTIVES: To analyze the inflammatory millieu in oral squamous cell carcinoma (OSCC) tumors and the influence of macrophages related-cytokines on the tumor cell migration. MATERIALS AND METHODS: Inflammatory protein profile and macrophage population (M2/M1 ratio) of human OSCC fragments were analyzed by proteomic analysis and flow cytometry assay respectively. To evaluate the effects of inflammation on OSCC behavior, we analyzed the role of polarized macrophages and cytokines (IL-6, IL-1ß and TNF-α) on OSCC cell lines (SCC25 and Cal27) responsiveness by western blotting (cell signaling) and time-lapse (cell migration). Also, it was addressed the crosstalk of IL-6-STAT3 axis with cell migration signaling using a STAT3 inhibitor (Stattic®) and a pull down assay for the RhoGTPase Rac1 activity. RESULTS: It was observed a ~2 fold predominance of M2 over M1 macrophages and a pro-inflammatory state in OSCC fragments. The M2 conditioned media increased migration speed and directionality of highly invasive OSCC cells (SCC25). OSCC cell lines were responsive to cytokine stimuli (IL6, IL-1ß and TNF-α), but only IL-6 increased migration properties of OSCC cells. This effect was dependent on STAT3-phosphorylation levels, which interfered with Rac1 activation levels. CONCLUSION: Our results suggest that the inflammatory milieu might favor invasion and metastasis of OSCC by the direct effect of macrophage-related cytokines on tumor migration.

Targeting Tumor-Associated Macrophages by MMP2-Sensitive Apoptotic Body-Mimicking Nanoparticles.

Tumor-associated macrophages (TAMs), a major player in the tumor microenvironment, were recently recognized as a potential therapeutic target. To date, very few anticancer drugs or drug-delivery systems were designed to target the TAMs. Inspired by the "eat me" signal, phosphatidylserine (PS), mediated phagocytic clearance of apoptotic bodies, in this study, the matrix metalloproteinase 2 (MMP2)-sensitive PS-modified nanoparticles were developed. In the design, the PS is externalized to the nanoparticles' surface only when the nanoparticles reach the MMP2-overexpressing tumor site, allowing for the TAM-specific phagocytosis. The nanoparticles' excellent macrophage/TAM selectivity was observed in various biological models, including various cell lines, coculture cells, coculture cell spheroids, zebrafish, and tumor-bearing mice. The nanoparticles' TAM specificity remarkably enhanced the TAM depletion capability of the loaded model drug, dasatinib, resulting in the improved anticancer activity. The MMP2-sensitive apoptotic body-mimicking nanoparticles might be a promising delivery tool for TAM-centered cancer diagnoses and treatments.

Resveratrol and Tumor Microenvironment: Mechanistic Basis and Therapeutic Targets.

Resveratrol (3,4',5 trihydroxystilbene) is a naturally occurring non-flavonoid polyphenol. It has various pharmacological effects including antioxidant, anti-diabetic, anti-inflammatory and anti-cancer. Many studies have given special attention to different aspects of resveratrol anti-cancer properties and proved its high efficiency in targeting multiple cancer hallmarks. Tumor microenvironment has a critical role in cancer development and progression. Tumor cells coordinate with a cast of normal cells to aid the malignant behavior of cancer. Many cancer supporting players were detected in tumor microenvironment. These players include blood and lymphatic vessels, infiltrating immune cells, stromal fibroblasts and the extracellular matrix. Targeting tumor microenvironment components is a promising strategy in cancer therapy. Resveratrol with its diverse biological activities has the capacity to target tumor microenvironment by manipulating the function of many components surrounding cancer cells. This review summarizes the targets of resveratrol in tumor microenvironment and the mechanisms involved in this targeting. Studies discussed in this review will participate in building a solid ground for researchers to have more insight into the mechanism of action of resveratrol in tumor microenvironment.

The Macrophages-Microbiota Interplay in Colorectal Cancer (CRC)-Related Inflammation: Prognostic and Therapeutic Significance.

Tumor-associated macrophages (TAMs) are the main population of myeloid cells infiltrating solid tumors and the pivotal orchestrators of cancer-promoting inflammation. However, due to their exceptional plasticity, macrophages can be also key effector cells and powerful activators of adaptive anti-tumor immunity. This functional heterogeneity is emerging in human tumors, colorectal cancer (CRC) in particular, where the dynamic co-existence of different macrophage subtypes influences tumor development, outcome, and response to therapies. Intestinal macrophages are in close interaction with enteric microbiota, which contributes to carcinogenesis and affects treatment outcomes. This interplay may be particularly relevant in CRC, one of the most prevalent and lethal cancer types in the world. Therefore, both macrophages and intestinal microbiota are considered promising prognostic indicators and valuable targets for new therapeutic approaches. Here, we discuss the current understanding of the molecular circuits underlying the interplay between macrophages and microbiota in CRC development, progression, and response to both conventional therapies and immunotherapies.

Protein-Bound Polysaccharides from Coriolus Versicolor Fungus Disrupt the Crosstalk Between Breast Cancer Cells and Macrophages through Inhibition of Angiogenic Cytokines Production and Shifting Tumour-Associated Macrophages from the M2 to M1 Subtype.

BACKGROUND/AIMS: The tumour microenvironment is rich in multiple cells that influence cancer development. Among them, macrophages are the most abundant immune cells, which secrete factors involved in carcinogenesis. Since protein-bound polysaccharides (PBP) from the Coriolus versicolor fungus are believed to inhibit the growth of cancers, in the present study, we investigated whether these PBP influence crosstalk between triple-negative 4T1 breast cancer cells and RAW 264.7 macrophages. METHODS: 4T1 cells were cultured in conditioned media (CM) collected after: stimulation of the macrophages with PBP (CM-PBP) or incubation of non-treated macrophages (CM-NT). A co-cultured model of both cell lines was also employed to investigate the crosstalk between the cells. Cell viability was measured using the MTT assay. The levels of cytokines and chemokines were determined by ELISA methods. Commercial assay kits were used to assess the activity of both arginase 1 and inducible nitric oxide synthase (iNOS) and the level of cell migration. RESULTS: The results revealed that CM-NT promotes proliferation and migration of 4T1 cells, and increases the secretion of pro-angiogenic factors (VEGF, MCP-1) by cancer cells. In contrast, CM-PBP inhibits 4T1 cell growth and migration, decreases the secretion of pro-angiogenic factors (VEGF, MCP-1) and upregulates the production of pro-inflammatory mediators (IL-6, TNF-α) with certain anti-tumoral properties Moreover, PBP-treated CM significantly decreases the level of M2 macrophage markers (arginase 1 activity, IL-10 and TGF-ß concentrations), but upregulates iNOS activity and IL-6 and TNF-α production, which are M1 cell markers. CONCLUSION: The results suggest that PBP suppress the favourable tumour microenvironment by inhibiting the crosstalk between 4T1 cells and macrophages through the regulation of production of angiogenic and inflammatory mediators, and modulating the M1/M2 macrophage subtype.