PACM-10 CELLULAR CROSSTALK IN THE BRAIN MICROENVIRONMENT PROMOTES MELANOMA INVASION AND GROWTH

Clonal evolution and stromal crosstalk drive an invasive epithelial program in bladder cancer

Tumor progression and metastasis in bladder cancer are driven by epithelial cell heterogeneity and dynamic interactions with the tumor microenvironment. To elucidate epithelial subpopulations associated with cancer progression, we performed single-cell transcriptomic profiling of bladder cancer tissues and identified a distinct epithelial subset, termed Meta-program 6 (MP6), that was significantly enriched in samples exhibiting lymphovascular invasion or lymph node metastasis. The MP6 gene signature correlated strongly with advanced tumor stage, lymph node involvement, and lymphovascular infiltration. CNV analysis revealed extensive chromosomal alterations, particularly chromosome 19 deletion, indicating genomic instability. Cell–cell communication analysis demonstrated active crosstalk between MP6 tumor cells and cancer-associated fibroblasts, including WNT and BMP signaling pathways, indicating that stromal crosstalk may contribute to the establishment of a pro-tumorigenic microenvironment. Transcription factor network inference further identified elevated activity of regulators such as TFCP2 and ELF1, implicating them in the acquisition of aggressive phenotypes. Immunohistochemical validation supported the clinical relevance of selected MP6-associated targets. Collectively, these findings define a clonally evolved epithelial subtype associated with lymphatic invasion and provide mechanistic insights into tumor cell plasticity and stromal–epithelial interactions underlying bladder cancer progression.

PI3K signaling promotes inflammatory tumor-macrophage crosstalk associated with mesenchymal glioblastoma

Background Glioblastoma (GBM) is a highly heterogeneous and vascularized malignancy in which the mesenchymal (MES) subtype is associated with poor prognosis, extensive macrophage infiltration and resistance to therapy. However, the signaling mechanisms integrating vascular remodeling with inflammatory tumor-macrophage crosstalk remain incompletely understood. Methods We integrated magnetic resonance imaging-derived vascular phenotyping with transcriptomic analyses of human glioblastoma cohorts to identify molecular pathways associated with highly vascular tumors. Functional studies using glioblastoma cell lines, THP-1-derived macrophages and co-culture systems were performed to investigate the role of PI3K signaling in tumor-macrophage communication. Finally, an independent single-cell transcriptomic cohort of primary human glioblastoma was interrogated to determine whether the identified inflammatory programs were conserved in malignant cells from patient tumors. Results Integrated imaging-transcriptomic analyses identified highly vascular glioblastomas as tumors enriched for the MES subtype, increased macrophage infiltration and activation of PI3K-associated signaling. Pharmacological inhibition of PI3K reduced the expression of macrophage-recruiting cytokines and impaired the ability of glioblastoma cells to educate macrophages toward an immunosuppressive phenotype. Reciprocally, tumor-educated macrophages enhanced inflammatory signaling, immune checkpoint expression and migratory capacity in glioblastoma cells, whereas IL-6 blockade attenuated these effects, identifying IL-6 as a key mediator of this bidirectional communication. To determine whether these inflammatory programs were conserved in human disease, we analyzed an independent single-cell transcriptomic dataset of primary glioblastomas. MES-like malignant cells exhibited the strongest inflammatory transcriptional programs among the four malignant transcriptional states, including higher NF-κB activation program scores and tumor-macrophage communication signature scores. At the tumor level, MES-like enrichment was positively associated with higher inflammatory program activity, supporting the clinical relevance of the proposed signaling axis. Conclusions Together, our findings identify PI3K signaling as a central regulator integrating vascular remodeling with inflammatory tumor-macrophage communication in mesenchymal glioblastoma. These results provide a mechanistic framework linking PI3K signaling, macrophage education and the MES phenotype, and provide a rationale for therapeutic strategies aimed at disrupting inflammatory signaling within the glioblastoma microenvironment.

Cell competition within breast tumor microenvironment: emerging role of cancer stem cells and immune cells in tumor progression and therapeutic implications

This review consolidates emerging evidence that positions cell competition as a critical regulator of clonal dynamics within the breast cancer TME and identifies competitive cellular fitness as a central and targetable driver of therapeutic resistance and tumor recurrence in breast cancer.

TAOK3 inhibition constrains invasion, potentiates paclitaxel, and reprograms the tumor microenvironment toward anti-tumor immunity in cervical cancer

Tumor Plasticity and Microenvironmental Crosstalk as Drivers of Metastasis and Therapy Resistance

Tumor plasticity and microenvironmental heterogeneity are established as an integrated, evolving system that fuels metastasis and limits durable treatment responses.

Single-Cell Dissection of the Immune Microenvironment in Intrahepatic Metastasis of Multifocal Hepatocellular Carcinoma

Intrahepatic metastasis in multifocal hepatocellular carcinoma is associated with poor prognosis and therapeutic resistance, yet the immune mechanisms driving disease progression remain unclear. Here, we analyzed genetic and immune differences between primary tumors and intrahepatic metastatic lesions using sequencing approaches and spatial validation methods. We found that metastatic lesions shared key genomic features with primary tumors but exhibited a distinct immunosuppressive environment enriched in myeloid and T cell populations. In particular, a subset of macrophages expressing glycoprotein nonmetastatic melanoma protein B (GPNMB) was consistently enriched in metastatic niches across multiple independent cohorts. These macrophages were spatially colocalized with CD8+ T cells exhibiting features of terminal exhaustion. Mechanistically, integrated multiomics and functional analyses revealed that GPNMB overexpression triggers lipid metabolic rewiring via the phosphatidylinositol 3-kinase/AKT-cyclooxygenase-2 cascade, leading to elevated prostaglandin E2 secretion, which directly suppresses CD8+ T cell cytotoxicity. Specific silencing of this subset using a dual-targeted, lipid-polymer nanoparticle (APLsiGpnmb) effectively reversed T cell exhaustion, inhibited metastasis, and synergized with anti-programmed death 1 immunotherapy in mouse models without inducing systemic toxicity. These findings identify GPNMB-positive macrophages as key metabolic and immune regulatory hubs, suggesting that targeting the GPNMB–prostaglandin E2 axis provides a promising precision therapeutic strategy for intrahepatic metastasis in multifocal hepatocellular carcinoma.