SPOP downregulation promotes bladder cancer progression based on cancer cell-macrophage crosstalk via STAT3/CCL2/IL-6 axis and is regulated by VEZF1

SLAMF8 regulates Fc receptor-mediated phagocytosis in mouse macrophage cells through PI3K-Akt signaling

Emerging studies have demonstrated that phagocytosis checkpoints, which promote tumor-mediated immune evasion, are potential targets for cancer immunotherapy. In this study, the TCGA colorectal cancer (CRC) dataset and our RNA sequencing dataset suggested that SLAMF8 expression is significantly positively correlated with the expression levels of multiple phagocytosis checkpoint molecules. In vitro, we confirmed that SLAMF8 significantly regulated the phagocytosis of mouse CRC cells. RNA sequencing revealed that the expression of genes that promote Fc receptor (FcR)-mediated phagocytosis, such as FCGR1, FCGR3, FCGR2b, FCGR4, and ITGAM, was significantly upregulated after SLAMF8 knockdown. The Kyoto Encyclopedia of Genes and Genomes (KEGG) results suggested that the significantly enriched signaling pathways after SLAMF8 knockdown or overexpression included the PI3K-Akt signaling pathway. The protein expression levels of p-PI3K and p-Akt were significantly increased after SLAMF8 knockdown. When PI3K inhibitors and Fc blockers were added after SLAMF8 knockdown, mouse macrophage phagocytosis, and FcR expression decreased. Our results suggest that SLAMF8 may impair FcR-mediated phagocytosis through the PI3K-Akt signaling pathway and negatively regulate the antitumor immune response.

Dual cytokine-engineered macrophages rejuvenate the tumor microenvironment and enhance anti-PD-1 therapy in renal cell carcinoma

Despite advances in PD-1 blockade therapy, the immunosuppressive tumor microenvironment (TME) limits its efficacy in renal cell carcinoma (RCC). Here, we developed dual-cytokine-engineered macrophages co-delivering IL-12 and CXCL-9 to reprogram TME and enhance anti-PD-1 responsiveness. Single-cell RNA sequencing revealed that RCC harbor abundant M2-like tumor-associated macrophages (TAMs), which correlate with T-cell exhaustion. In vitro, engineered macrophages polarized M2-like TAMs to antitumor M1 phenotypes, secreted CXCL-9 to recruit cytotoxic T cells, and released IL-12 to amplify T/NK cell activation. In vivo, intravenously administered engineered macrophages homed to tumors, reshaped the TME by increasing CD8+ T cells, dendritic cells, and NK cells while reducing immunosuppressive Tregs and MDSCs. This approach synergized with PD-1 blockade, resulting in a 2.5-fold greater tumor growth inhibition compared to anti-PD-1 monotherapy. This dual-cytokine macrophage platform offers a novel strategy to overcome resistance to checkpoint inhibitors in RCC by delivering cytokine and remodeling TME, with implications for clinical translation.

APOC1 expressed in macrophages promotes the pulmonary metastasis of colorectal cancer via CCL2/CCL5

Metastasis is the main cause of death in colorectal cancer (CRC), and the lungs are common sites of metastasis. However, there is little effective target to intervene colorectal cancer pulmonary metastasis (CCPM), especially on its unique immune microenvironment. In this study, sixteen genes were identified as core CCPM-related differentially expressed genes (DEGs) between CRC and CCPM. Three genes including Apolipoprotein C1 (APOC1) were associated with prognosis, stage and metastasis of CRC. In immunohistochemistry, APOC1 was mainly expressed in macrophages, and expressed more in CCPM than CRC. Patients with synchronous CCPM, higher stage, poorer OS and CCPM-free interval tended to have higher expression. In experiments in vitro, knockdown of APOC1 in macrophages reduced the migration, invasion, and epithelial-mesenchymal transition of CRC cells. Knockdown of APOC1 in macrophages significantly decreased secretion of chemokines like CCL2 and CCL5. The pro-metastatic effect of macrophages expressing APOC1 was partially blocked by the antibodies of CCL2 and CCL5. Activation of STAT3 was a key process in APOC1's regulation of CCL2 and CCL5. In experiments in vivo, knockdown of APOC1 in macrophages reduced pulmonary metastasis. To conclude, APOC1 is one of core CCPM-related DEGs and associated with the metastasis and survival of CRC. Macrophages expressing APOC1 promote the CCPM by APOC1-STAT3-CCL2/CCL5 axis. APOC1 and macrophages expressing APOC1 play vital roles and may be potential therapeutic targets in CCPM.

Key immune cells and their crosstalk in the tumor microenvironment of bladder cancer: insights for innovative therapies

Bladder cancer (BC) is a heterogeneous disease associated with high mortality if not diagnosed early. BC is classified into non-muscle-invasive BC (NMIBC) and muscle-invasive BC (MIBC), with MIBC linked to poor systemic therapy response and high recurrence rates. Current treatments include transurethral resection with Bacillus Calmette-Guérin (BCG) therapy for NMIBC and radical cystectomy with chemotherapy and/or immunotherapy for MIBC. The tumor microenvironment (TME) plays a critical role in cancer progression, metastasis, and therapeutic efficacy. A comprehensive understanding of the TME's complex interactions holds substantial translational significance for developing innovative treatments. The TME can contribute to therapeutic resistance, particularly in immune checkpoint inhibitor (ICI) therapies, where resistance arises from tumor-intrinsic changes or extrinsic TME factors. Recent advancements in immunotherapy highlight the importance of translational research to address these challenges. Strategies to overcome resistance focus on remodeling the TME to transform immunologically "cold" tumors, which lack immune cell infiltration, into "hot" tumors that respond better to immunotherapy. These strategies involve disrupting cancer-microenvironment interactions, inhibiting angiogenesis, and modulating immune components to enhance anti-tumor responses. Key mechanisms include cytokine involvement [e.g., interleukin-6 (IL-6)], phenotypic alterations in macrophages and natural killer (NK) cells, and the plasticity of cancer-associated fibroblasts (CAFs). Identifying potential therapeutic targets within the TME can improve outcomes for MIBC patients. This review emphasizes the TME's complexity and its impact on guiding novel therapeutic approaches, offering hope for better survival in MIBC.

Emodin Decreases Tumor-Associated Macrophages Accumulation and Suppresses Bladder Cancer Development by Inhibiting CXCL1 Secretion from Cancer-Associated Fibroblasts

Tumor-associated macrophages (TAMs) and cancer-associated fibroblasts (CAFs) are the most abundant stromal cells in the bladder cancer (BC) microenvironment (TME). However, the detailed mechanisms underlying TAM-CAF communication and their contributions to BC progression remain incompletely understood. Emerging evidence shows that Emodin exerts anti-tumor effect on several tumor models by targeting TME. To date, the impact of Emodin on BC has not been previously reported. Our study firstly demonstrated that Emodin significantly inhibited tumor growth and reduced TAM accumulation in a murine BC model. Emodin markedly decreased serum levels of multiple chemokines in tumor-bearing mice, with CXCL1 showing the most pronounced reduction. Strikingly, Emodin selectively suppressed CXCL1 secretion in CAFs but not in TAMs or tumor cells. Furthermore, the decrease in TAM migration induced by Emodin was dependent on CAF-derived CXCL1. Using a subcutaneous tumor model, we found that Emodin failed to inhibit tumor growth when CXCL1-deficient CAFs were co-injected with tumor cells, underscoring the critical role of CXCL1 in this process. Bioinformatics analysis further revealed that elevated CXCL1 levels correlated negatively with invasive/metastatic potential and overall survival in BC patients. In conclusion, our findings establish that Emodin delays BC progression by disrupting CXCL1-mediated crosstalk between CAFs and TAMs.