BACKGROUND: Lung adenocarcinoma (LUAD) remains one of the leading causes of cancer morbidity and mortality worldwide, and its initiation and progression are closely associated with the tumor immune microenvironment. Increasing evidence suggests that environmental exposure is a critical factor influencing lung cancer development. Among these factors, fine particulate matter (PM2.5), a major component of air pollution, has been strongly linked to elevated lung cancer risk and unfavorable prognosis. However, the underlying immunoregulatory mechanisms by which PM2.5 drives LUAD progression remain poorly understood. Tumor-associated macrophages (TAMs), especially those polarized toward the M2 phenotype, are key components of the tumor microenvironment and play crucial roles in tumor growth, angiogenesis, and immune evasion. This study aims to investigate the effects of PM2.5 exposure on TAMs and to identify the key pro-tumorigenic factors mediating this process. METHODS: A mouse orthotopic lung cancer model under PM2.5 exposure was established to assess lung tumor growth and macrophage phenotypic alterations using in vivo imaging and flow cytometry. A subcutaneous tumor model involving co-inoculated macrophages and tumor cells was used to further verify the effects of PM2.5 on the function of TAMs and tumor malignancy. Combining in vitro experiments, flow cytometry, Western blot, reverse transcription quantitative polymerase chain reaction (RT-qPCR), cell counting kit-8 (CCK-8) assay, colony formation assay, and wound healing assay were employed to evaluate the regulatory effects of PM2.5 on the polarization of bone marrow-derived macrophages (BMDMs) as well as tumor cell proliferation, migration, and colony-forming ability. Transcriptome sequencing integrated with TISIDB (Tumor-immune System Interactions Database) and GEPIA (Gene Expression Profiling Interactive Analysis) databases was performed to identify key cytokines for further functional validation. RESULTS: In the mouse orthotopic lung cancer model, PM2.5 exposure significantly promoted tumor growth and increased the proportion of M2-type TAMs (P<0.05). Subcutaneous co-inoculation with PM2.5-treated BMDMs markedly enhanced tumor proliferation and elevated the intratumoral M2-type TAMs. PM2.5-pretreated BMDMs exhibited an immunosuppressive programmed cell death ligand 1 (PD-L1)+/arginase 1 (Arg1)+ phenotype, and their conditioned media significantly promoted proliferation, migration, and colony formation of Lewis lung carcinoma cells (LLC) and B16 melanoma cells (B16) (P<0.05). Transcriptome analysis revealed that PM2.5 substantially altered macrophage gene expression, with IL-1α identified as a key upregulated secreted cytokine enriched in immunosuppressive related signaling pathways. Clinical database analyses further indicated that IL-1α expression was positively correlated with macrophage and regulatory T cells (Treg) infiltration in the LUAD immune microenvironment, and that high IL-1α expression was associated with worse overall survival in LUAD patients (HR=1.5, P=0.0053). Western blot, RT-qPCR, and immunofluorescence confirmed that PM2.5 exposure significantly upregulated IL-1α expression and secretion in TAMs. CONCLUSIONS PM2.5 exposure facilitates LUAD progression by inducing an immunosuppressive phenotype in macrophages and enhancing the malignant behaviors of tumor cells. Mechanistically, IL-1α may serve as a key pro-tumorigenic cytokine secreted by macrophages under PM2.5 exposure. This study provides new insights into the pathogenesis of PM2.5-associated LUAD and suggests that IL-1α could serve as a potential therapeutic target.
Animals ; Mice ; Tumor-Associated Macrophages/immunology* ; Particulate Matter/toxicity* ; Adenocarcinoma of Lung/metabolism* ; Lung Neoplasms/genetics* ; Humans ; Disease Progression ; Tumor Microenvironment/drug effects* ; Cell Proliferation/drug effects* ; Cell Line, Tumor

Our previous research demonstrated that the Wenxia Changfu Formula (WCF), as a neoadjuvant therapy, inhibits M2 macrophage infiltration in the tumor microenvironment and prevents lung cancer metastasis. Given tumor-associated macrophages (TAMs) in epithelial-mesenchymal transition (EMT), this study investigated whether WCF impedes lung cancer metastasis by attenuating TAM-induced EMT in non-small cell lung cancer (NSCLC) cells. Utilizing a co-culture model treated with or without WCF, we observed that WCF downregulated cluster of differentiation 163 (CD163) expression in macrophages, reduced CCL18 levels in the conditioned medium, and inhibited the growth, invasion, and EMT of NSCLC cells induced by macrophage co-culture. Manipulation of CCL18 levels and Src overexpression in NSCLC cells revealed that WCF's effects are mediated through CCL18 and Src signaling. In vivo, WCF inhibited recombinant CCL18 (rCCL18)-induced tumor metastasis in nude mice by blocking Src signaling. These findings indicate that WCF inhibits NSCLC metastasis by impeding TAM-induced EMT via antagonistic modulation of CCL18, providing evidence for its potential development and clinical application in NSCLC patients.
Epithelial-Mesenchymal Transition/drug effects* ; Carcinoma, Non-Small-Cell Lung/metabolism* ; Humans ; Animals ; Lung Neoplasms/metabolism* ; Chemokines, CC/antagonists & inhibitors* ; Mice ; Mice, Nude ; Drugs, Chinese Herbal/administration & dosage* ; Cell Line, Tumor ; Neoplasm Metastasis ; Tumor-Associated Macrophages/drug effects* ; Mice, Inbred BALB C ; Signal Transduction/drug effects*

Tumor-associated macrophages (TAMs), a crucial component of the tumor microenvironment (TME), are closely associated to the growth, invasion, metastasis, and prognosis of breast cancer. Targeting TAMs is considered to be a potential new strategy for improving the therapeutic efficacy of breast cancer. TAMs interact with breast cancer cells and influence the development and progression of various breast cancer subtypes through multiple pathways, including the secretion of proteins, cytokines, chemokines, and exosomes. Anti-breast cancer drugs targeting TAMs and emerging therapies are continually being discovered. This article explores the effects and mechanisms of TAMs in different breast cancer subtypes, examines the anti-breast cancer effects of herbal extracts and their active ingredients targeting TAMs, and introduces new technologies such as nano-agents, gene therapy, and immunocellular therapy that target TAMs. These therapeutic strategies targeting TAMs may be critical in improving the therapeutic efficacy and prognosis of breast cancer patients.
Humans ; Breast Neoplasms/pathology* ; Female ; Tumor-Associated Macrophages/drug effects* ; Tumor Microenvironment/drug effects* ; Animals ; Molecular Targeted Therapy/methods*

OBJECTIVETo characterize the role of tumor necrosis factor-α (TNF-α) and NF-κB play a role in macrophage-like THP-1 cells promoting coal tar pitch extract (CTPE)-induced tumorigenic transformation of human bronchial epithelial cells (BEAS-2B).

METHODSFrom passage 10, CTPE-induced BEAS-2B cells cocultured with THP-1 cells were treated with NF-κB inhibitor-Pyrrolidine dithiocarbamate (PDTC) every 3 passages and TNF-α antibody every passage. Alterations of cell cycle, karyotype and colony formation in soft agar of BEAS-2B cells at passages 20, indicative of tumorigenicity, were determined, respectively. In addition, mRNA and protein levels of TNF receptor associated factor2 (TRAF2) and Cyclin D1 in BEAS-2B cells were measured with Real Time-PCR and Western blot, respectively.

RESULTSThe percentages of S-phase BEAS-2B cells at passage 20 in PDTC group and TNF-α antibody group were (33.97±2.16)% and (34.29±2.04)% respectively, which were less than that in Co-culture+CTPE group of 20th passage [(44.46±0.83)%], P < 0.05; The number of cells with aneuploidy in 100 cells in 20th passage PDTC group and TNF-α antibody group were 40 and 37, and there were significantly different when comparing to that of 20th passage Co-culture+CTPE group (75); The number of colony formation and the rate of colony formation of BEAS-2B cells in soft agar at passage 20 in PDTC group were (15.17±2.48) and (1.51‰±0.25‰), (13.33±2.58)and (1.33‰±0.26‰) in TNF-α antibody group, which were less that those in 20th passage Co-culture+CTPE group [(172.33±12.09) and (17.23‰±1.20‰)], P < 0.05; at the same time, the mRNA and protein levels of TRAF2 and Cyclin D1 in BEAS-2B cells were decreased after PDTC and TNF-α antibody treatment.

CONCLUSIONTNF-α and NF-κB could play an important role in THP-1 cells promoting coal tar pitch extract-induced tumorigenic transformation of BEAS-2B cells by influencing the expression of TRAF2 and Cyclin D1.

Bronchi ; cytology ; Cell Line ; Cell Transformation, Neoplastic ; drug effects ; Coal Tar ; toxicity ; Cyclin D1 ; metabolism ; Epithelial Cells ; cytology ; Humans ; Macrophages ; cytology ; NF-kappa B ; metabolism ; TNF Receptor-Associated Factor 2 ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism