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• Bioinformatics analysis revealed that TRIM65 expression was upregulated in HCC； • High level of TRIM65 was strongly correlated with immune infiltration level of macrophages in HCC. • TRIM65 knockout significantly inhibits the tumor growth as well as macrophage infiltration in vivo. • TRIM65 knockout promoted macrophage M1 polarization in vitro and in vivo by activating JAK1/STAT1 signaling pathway. Tumor-associated macrophages (TAMs) are main components of immune cells in tumor microenvironment (TME), and play a crucial role in tumor progression. Tripartite motif-containing protein 65 (TRIM65) has been associated with tumor progression. However, whether TRIM65 regulate the interaction of tumor cell and TAMs in HCC and the underlying mechanisms remain unknown. In this study, we investigated the role of TRIM65 in TME of HCC and explored its underlying mechanisms. The relation of TRIM65 expression level with tumor grades, TNM stages, and worse prognosis of HCC patients was evaluated by bioinformatics analysis, as well as immune infiltration level of macrophages. TRIM65 shRNA was transfected into HepG2 cells, and TRIM65 overexpression plasmid was transfected into Huh7 cells, and the effect of TRIM65 on cell growth was examined by EdU assay. The mouse subcutaneous Hep1-6 tumor-bearing model with WT and TRIM65-/- mice was established to study the role of TRIM65 in HCC. Immunohistochemistry staining, Immunofluorescence staining, qRT-PCR and western blot were performed to evaluate the effect of TRIM65 on TAM infiltration, TAM polarization and JAK1/STAT1 signaling pathway. Bioinformatics analysis revealed that TRIM65 was upregulated in 16 types of cancer especially in HCC, and high level of TRIM65 was strongly correlated with higher tumor grades, TNM stages, and worse prognosis of patients with HCC as well as immune infiltration level of macrophages (M0, M1, and M2). Moreover, we observed that TRIM65 shRNA-mediated TRIM65 knockdown significantly inhibited the HepG2 cells growth while TRIM65 overexpression highly increased the Huh7 cells growth in vitro. TRIM65 knockout significantly inhibited the tumor growth as well as macrophages polarization towards M2 but promoted macrophages polarization towards M1 in vivo. Mechanistically, the results demonstrate that TRIM65 knockout promoted macrophage M1 polarization in conditioned medium-stimulated peritoneal macrophages and in tumor tissues by activating JAK1/STAT1 signaling pathway. Taken together, our study suggests that tumor cells utilize TRIM65-JAK1/STAT1 axis to inhibit macrophage M1 polarization and promote tumor growth, reveals the role of TRIM65 in TAM-targeting tumor immunotherapy. [ABSTRACT FROM AUTHOR]

• GAD1 was overexpressed in LUAD and negatively correlated with LUAD patients' survial. • GABA promoted lung cancer progression not by directly affecting cancer cells. • GABA promoted lung cancer progression by affecting TAM polarization. • GABA prevented TAM from M1 polarization and promoted TAM M2 polarization. • GABA promoted tumor neovascularization. Gamma-aminobutyric acid (GABA), a common neurotransmitter, has been found in various cancers but its origin and its role in the tumor immune microenvironment remains unclear. Here, we reported the expression of glutamate decarboxylase 1 (GAD1, converting glutamate into GABA) in lung cancer tissues based on the publicly available database, and explored the effects and underlying mechanism of GABA on lung cancer progression. Compared with normal tissues, GAD1 was aberrantly overexpressed in lung adenocarcinoma (LUAD) based on TCGA database. Furthermore, the LUAD patients' overall survival was negatively correlated with the GAD1 expression levels. Our work found that a GABAa receptor inhibitor had a therapeutic effect on mouse tumors and significantly reduced tumor size and weight. Further experiments showed that GABA derived from tumor cells promoted tumor progression not by directly affecting cancer cells but by affecting macrophages polarization in the tumor microenvironment. We found that GABA inhibited the NF-κB pathway and STAT3 pathway to prevent macrophages from polarizing towards M1 type, while promoting macrophage M2 polarization by activating the STAT6 pathway. GABA was also found to promote tumor neovascularization by increasing the expression of FGF2 in macrophages. These results suggest that GABA affects tumor progression by regulating macrophage polarization, and targeting GABA and its signaling pathway may represent a potential therapy for lung cancer. [ABSTRACT FROM AUTHOR]

Abstract This study was to explore the effect and mechanisms of anti- human gastric cancer by MENK in vitro and in vivo. The results showed in MENK-treated xenograft tissue, the percentage of M2-type macrophages decreased while M1-type macrophages increased. MENK increased the expression of M1-related cytokine TNF-α and attenuated the expression of M2-related cytokine IL-10 expression. MENK upregulated the expression of opioid receptor (OGFr), while it inhibited HGC27 and SGC7901 cells through blocking PI3K/AKT/mTOR signal pathway in vitro and in vivo. These effects of MENK could be cancelled when OGFr was knockdown. This indicates that binding to OGFr by MENK appears to be essential for the anti- GC cells. Therefore, it is concluded that MENK might skew macrophage toward M2 phenotype from M1 phenotype within tumor and induce cells apoptosis though blocking OGFr/PI3K/AKT/mTOR signaling pathway. Highlights • MENK could inhibit the growth of human gastric cancer (GC). • MENK exerts an antitumor activity though reversing TAMs polarization from M2 to M1. • OGFr has been proven to as a functional target for MENK to regulate proliferation and apoptosis of GC cells. • MENK inhibits proliferation and induces apoptosis via OGFr/PI3K/AKT/mTOR signaling pathway. [ABSTRACT FROM AUTHOR]

• HMGB1 in oral cancer cells affected tumor-associated macrophage polarization. • HMGB1 in macrophages affected the cocultured tumor cell proliferation and invasion. • Secreted HMGB1 regulted the crosstalk between tumor cells and 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. [ABSTRACT FROM AUTHOR]

• Erastin promotes M2 polarization at least partially via the STAT3 signaling pathway. • Erastin-stimulated macrophages promote ferroptosis-resistant ovarian cancer cell metastasis through EMT. • IL-8 is the key cytokine secreted by erastin-treated macrophages. • Blockage of IL-8 effectively abrogates the metastatic potential of ferroptosis-resistant ovarian cancer cells induced by erastin-stimulated M2 macrophages. Erastin is a small molecule identified in chemical screen that is capable of inducing ferropotosis. There is collective evidence proving that erastin-induced ferroptosis exhibits anti-tumor potential within diverse caners, such as ovarian cancer (OC). However, most OC cells show relative resistance to ferroptosis induced by erastin. M2-polarized tumor-associated macrophages (TAMs) have an important effect on the OC tumor microenvironment (TME), which makes M2 polarization a noticeable part in the context of OC therapy. The immunomodulatory effects of erastin on ferroptosis-resistant OC cells remain poorly understood. Here, we found that low concentration of erastin greatly promoted ferroptosis-resistant OC cell invasion and migration via STAT3-mediated M2 polarization of macrophages. As revealed by in-vitro experimental results, erastin significantly increased metastases of ferroptosis-resistant OC, and the percentage of M2 macrophage infiltration was also raised after erastin treatment. Furthermore, erastin augmented IL-8 production of macrophages, and pharmacological blockage of IL-8 partially abrogated the stimulatory effect of erastin on ferroptosis-resistant OC cells. This study demonstrates a new mechanism undering the tumor-promoting activity of erastin and has implications for the STAT3/IL-8 axis as a potential target for ferroptosis-resistant OC cells to improve overall anti-tumor efficacy. [ABSTRACT FROM AUTHOR]

• Tumor-associated macrophages (TAMs) infiltration is obviously increased and closely associated with tumor progression and poor prognosis in renal cell carcinoma (RCC). • TAMs significantly promoted RCC cells migration, invasion and epithelial-mesenchymal transition (EMT). • TAMs promote migration, invasion and EMT via activating IL-6/STAT3 signaling in RCC. Tumor-associated macrophages (TAMs) promote tumor cell growth and metastasis in various human cancers. However, the role of TAMs in renal cell carcinoma (RCC) is rarely investigated. Herein, we observed that the infiltration of TAMs was obviously elevated in RCC tumor tissues, high infiltration of TAMs was closely associated with tumor progression and poor prognosis in RCC patients. In vitro assays further indicated that the conditioned medium of TAMs (TAMs CM) facilitated migration, invasion, and epithelial-mesenchymal transition (EMT) in RCC cells. Moreover, we found that IL-6 was involved in the functions of TAMs in RCC; IL-6 neutralizing antibody (IL-6NA) partly abolished the effect of TAMs on RCC cells. In addition, we demonstrated that TAMs might exert their roles by activating STAT3 signaling in RCC, and IL-6 was responsible for TAMs-induced STAT3 signaling activation. In conclusion, our results revealed that high infiltration of TAMs may promote RCC cells migration, invasion, and EMT via modulating IL-6/STAT3 signaling, further suggesting a potential of novel treatment strategies targeting TAMs or IL-6 for metastatic RCC. [ABSTRACT FROM AUTHOR]

Diagnosis of cancer and photothermal therapy using optoelectronic properties of noble metal nanoparticles (NPs) has established a new therapeutic approach for treating cancer. Here we address the intrinsic properties of noble metal NPs (gold and silver) as well as the mechanism of their potential antitumor activity. For this, the study addresses the functional characterization of tumor associated macrophages (TAMs) isolated from murine fibrosarcoma induced by a chemical carcinogen, 3-methylcholanthrene (MCA). We have previously shown antitumor activity of both gold nanoparticles (AuNPs) and silver nanoparticle (AgNPs) in vivo in a murine fibrosarcoma model. In the present study, it has been seen that AuNPs and AgNPs modulate the reactive oxygen species (ROS) and reactive nitrogen species (RNS) production, suppressing the antioxidant system of cells (TAMs). Moreover, the antioxidant-mimetic action of these NPs maintain the ROS and RNS levels in TAMs which act as second messengers to activate the proinflammatory signaling cascades. Thus, while there is a downregulation of tumor necrosis factor-α (TNF-α) and Interleukin-10 (IL-10) in the TAMs, the proinflammatory cytokine Interleukin-12 (IL-12) is upregulated resulting in a polarization of TAMs from M2 ( anti -inflammatory) to M1 (pro-inflammatory) nature. [ABSTRACT FROM AUTHOR]

• TAMs-mediated CXCL8 is up-regulated in breast cancer and involved in metastasis. • Danirixin inhibits CXCL8-elevated migration and invasion in breast cancer cells. • Danirixin suppresses CXCL8-promoted BCSCs subpopulation and TAM-released CXCL8 mediated self-renewal of BCSCs. • Danirixin-treated TAMs inhibits breast cancer growth, pulmonary metastasis and BCSCs self-renewal activity in vivo. Breast cancer is the most frequent cancer among females and the second most common cause of cancer deaths worldwide. Tumor-associated macrophages (TAMs) are the most abundant immune cell population in the tumor microenvironment, including breast cancer. Breast cancer stem cells (BCSCs) play an important role in regulating breast cancer growth and metastasis, which still remains an obstacle for successful treatment of breast cancer and requires further investigation, as well as the potential therapeutic strategies. Cytokine array validated that C-X-C motif chemokine ligand 8 (CXCL8) is a pivotal chemokine secreted by TAMs, and CXCL8 could enhance breast cancer migration, invasion ability, and epithelial-mesenchymal transition (EMT) in both animal and human breast cancer. In this study, the clinical data firstly indicated that high CXCL8 expression was significantly associated with metastasis and tumor growth in breast cancer patients. Then, we showed that TAMs-released CXCL8 could markedly elevate the migration, invasion and EMT events in breast cancer cells, as well as the self-renewal of BCSCs in vitro. These processes were markedly abrogated by the treatment of Danirixin, a reversible and selective antagonist of CXC chemokine receptor 2 (CXCR2). Consistently, the in vivo analysis confirmed that CXCL8 suppression using Danirixin effectively reduced the tumor growth, lung metastasis and repressed the self-renewal of BCSCs. Collectively, TAMs/CXCL8 could enhance BCSCs self-renewal and breast cancer metastasis, and these effects could be markedly abolished by Danirixin treatment, suppressing breast cancer progression consequently. Therefore, Danirixin could be considered as a novel and effective therapeutic strategy for breast cancer treatment without obvious toxicity to major organs. [ABSTRACT FROM AUTHOR]

The infiltration of immune cells is a hallmark of most forms of malignancy. It is well known that in Tumor Microenvironment (TME), monocytes undergo reprogramming process to differentiate into Tumor Associated Macrophages (TAMs) (M2 macrophages). Interestingly, this reprogramming process depends on signals provided by tumors. Hence, tumors from several tissues are infiltrated by functionally distinct TAMs populations. Tumor Protein p53(TP53) plays a role in the regulation or progression of DNA damage and repair through multiple mechanisms of the cell cycle, apoptosis, and genomic stability. Although, TP53 acts as a physiological break for M2 macrophages polarization; the potential regulatory function of TP53 in the infiltration of macrophages is still unknown. We used the Cancer Genomic Atlas (TCGA) clinical data from 10,009 samples across 30 types of cancer via the Tumor IMmune Estimation Tool (TIMER) (https://cistrome.shinyapps.io/timer/) to investigate whether TP53 status has an important clinical outcome on macrophages infiltration in different cancer types. Our analysis of TCGA showed that Ovarian Serous Cystadenocarcinoma (OV) patients with mutant TP53 had significantly higher macrophages infiltration than those with wild-type TP53 (P-value < 0.05) and poor prognosis associated. In contrast, Stomach Adenocarcinoma (STAD) patients with wild-type TP53 had considerably higher macrophages infiltration than those with mutant TP53 (P-value < 0.01) and poor clinical outcomes. Herein, our study sheds light on the novel clinical role of TP53 in macrophages infiltration in TME of OV and STAD patients. Furthermore, the modulation of TP53 and its co-regulators may serve as promising targets for OV and STAD patients. [ABSTRACT FROM AUTHOR]

• BML-111 inhibits EMT, migration and metastasis of Triple-negative breast cancer cells. • BML-111 inbibits Triple-negative breast cancer cells via ILK pathway. • BML-111 inbibits Triple-negative breast cancer cells by targeting TAMs. Triple-negative breast cancer (TNBC) has a more aggressive phenotype and higher metastasis and recurrence rates than other breast cancer subtypes. The immune microenvironment and hypoxic microenvironment of breast cancer constitute the survival environment of cancer cells, which is an important environment to support cancer cells. LXA 4 and its analog, BML-111 is an important regulator of inflammatory cytokines, which provides a possible way for the treatment of inflammatory-related tumors. Here, in the in vitro experiment, we showed that BML-111 could inhibit the EMT and migration of TAMs-stimulated TNBC by down-regulating ILK as well as p-Akt and p-GSK3β. And it could prevent the formation of breast cancer cell clusters. In the in vivo experiment, BML-111 could inhibit the metastasis of 4T1 breast cancer cells. We also demonstrated that BML-111 could affect macrophages in tumor microenvironment to prevent metastasis. These results showed that BML-111 could be a possible candidate for breast cancer therapy by targeting ILK and TAMs. [ABSTRACT FROM AUTHOR]