Dynamic changes in mechanical microenvironments, such as cell crowding, regulate lineage fates as well as cell proliferation. Although regulatory mechanisms for contact inhibition of proliferation have been extensively studied, it remains unclear how cell crowding induces lineage specification. Here we found that a well-known oncogene, ETS variant transcription factor 4 (ETV4), serves as a molecular transducer that links mechanical microenvironments and gene expression. In a growing epithelium of human embryonic stem cells, cell crowding dynamics is translated into ETV4 expression, serving as a pre-pattern for future lineage fates. A switch-like ETV4 inactivation by cell crowding derepresses the potential for neuroectoderm differentiation in human embryonic stem cell epithelia. Mechanistically, cell crowding inactivates the integrin-actomyosin pathway and blocks the endocytosis of fibroblast growth factor receptors (FGFRs). The disrupted FGFR endocytosis induces a marked decrease in ETV4 protein stability through ERK inactivation. Mathematical modelling demonstrates that the dynamics of cell density in a growing human embryonic stem cell epithelium precisely determines the spatiotemporal ETV4 expression pattern and, consequently, the timing and geometry of lineage development. Our findings suggest that cell crowding dynamics in a stem cell epithelium drives spatiotemporal lineage specification using ETV4 as a key mechanical transducer.

Dynamic changes in mechanical microenvironments, such as cell crowding, regulate lineage fates as well as cell proliferation. Although regulatory mechanisms for contact inhibition of proliferation have been extensively studied, it remains unclear how cell crowding induces lineage specification. Here we found that a well-known oncogene, ETS variant transcription factor 4 (ETV4), serves as a molecular transducer that links mechanical microenvironments and gene expression. In a growing epithelium of human embryonic stem cells, cell crowding dynamics is translated into ETV4 expression, serving as a pre-pattern for future lineage fates. A switch-like ETV4 inactivation by cell crowding derepresses the potential for neuroectoderm differentiation in human embryonic stem cell epithelia. Mechanistically, cell crowding inactivates the integrin-actomyosin pathway and blocks the endocytosis of fibroblast growth factor receptors (FGFRs). The disrupted FGFR endocytosis induces a marked decrease in ETV4 protein stability through ERK inactivation. Mathematical modelling demonstrates that the dynamics of cell density in a growing human embryonic stem cell epithelium precisely determines the spatiotemporal ETV4 expression pattern and, consequently, the timing and geometry of lineage development. Our findings suggest that cell crowding dynamics in a stem cell epithelium drives spatiotemporal lineage specification using ETV4 as a key mechanical transducer.

Neuroendocrine prostate cancer (NEPC), an aggressive subtype induced by hormone therapy, lacks effective treatments. This study explored the role of E26 transformation-specific variant 5 (ETV5) in NEPC development. Analysis of multiple prostate cancer datasets revealed that NEPC is characterized by significantly elevated <i>ETV5</i> expression compared to other subtypes. ETV5 expression increased progressively under hormone therapy through epigenetic modifications. ETV5 induced neural stem-like features in prostate cancer cells and facilitated their differentiation into NEPC under hormone treatment conditions, both in vitro and in vivo. Our molecular mechanistic study identified <i>PBX3</i> and <i>TLL1</i> as target genes of ETV5 that contribute to ETV5 overexpression-induced castration resistance and stemness. Notably, obeticholic acid, identified as an ETV5 inhibitor in this study, exhibited promising efficacy in suppressing NEPC development. This study highlights ETV5 as a key transcription factor that facilitates NEPC development and underscores its potential as a therapeutic target for this aggressive cancer subtype.

Abstract Exhausted CD8 + T (Tex) cells comprise heterogeneous subsets with varying cytotoxic and dysfunctional properties, making inhibitory receptor profiles unreliable indicators of function. Therefore, it is essential to define transcriptional regulators or markers that accurately reflect these states. Here, we identified ETS variant 4 (ETV4) as a transcription factor that restricts cytotoxic Tex differentiation within tumors. ETV4 deficiency promotes the emergence of a CD74 + cytotoxic Tex subset while preserving the progenitor Tex (Tpex) pool. CD74 serves as both a marker and regulator, reinforcing Tpex features and enhancing Tex cytotoxicity. Mechanistically, ETV4 loss derepresses T-bet expression, thereby increasing IFNγ production that induces CD74 expression in a paracrine manner. Single-cell analyses across human cancers revealed that CD74 + Tex cells are enriched for proliferative and metabolic programs and correlate with improved survival. Collectively, we establish the ETV4–CD74 axis as a regulator of Tex fate and promising therapeutic target to augment anti-tumor immunity.

Prostate cancer is one of the most common malignancies in men, with most cases initially responding to androgen deprivation therapy. However, a significant number of patients eventually develop castration-resistant prostate cancer, an aggressive form of the disease. Although androgen receptor (AR) pathway inhibitors target AR signaling, and have extended survival in patients with castration-resistant prostate cancer, prolonged treatment can lead to the emergence of neuroendocrine prostate cancer (NEPC), a lethal subtype characterized by the expression of neuroendocrine markers and reduced AR activity. The transition from adenocarcinoma to NEPC is driven by lineage plasticity, wherein cancer cells adopt a neuroendocrine phenotype to evade treatment. Consequently, NEPC patients face poor clinical outcomes and limited effective treatment options. To improve outcomes, it is crucial to understand the molecular mechanisms driving NEPC development. In this review, we highlight the role of transcription factors in this process and explore their potential as therapeutic targets.

Immune cells are distributed across various tissues. While a majority are concentrated in primary and secondary lymphoid organs such as the bone marrow, thymus, lymph nodes, and spleen, a subset resides in nonlymphoid organs, including the kidney, liver, and lung, as well as the peritoneal cavity, where they play critical roles in local immune surveillance and response. In this editorial, we outline concise and practical protocols for the isolation of immune cells from a range of lymphoid and nonlymphoid organs.

Follicular helper T (T_FH) cells mediate germinal center reactions to generate high affinity antibodies against specific pathogens, and their excessive production is associated with the pathogenesis of systemic autoimmune diseases such as systemic lupus erythematosus (SLE). ETV5, a member of the ETS transcription factor family, promotes T_FH cell differentiation in mice. In this study, we examined the role of ETV5 in the pathogenesis of lupus in mice and humans. T cell-specific deletion of <i>Etv5</i> alleles ameliorated T_FH cell differentiation and autoimmune phenotypes in lupus mouse models. Further, we identified <i>SPP1</i> as an ETV5 target that promotes T_FH cell differentiation in both mice and humans. Notably, extracellular osteopontin (OPN) encoded by <i>SPP1</i> enhances T_FH cell differentiation by activating the CD44-AKT signaling pathway. Furthermore, <i>ETV5</i> and <i>SPP1</i> levels were increased in CD4⁺ T cells from patients with SLE and were positively correlated with disease activity. Taken together, our findings demonstrate that ETV5 is a lupus-promoting transcription factor, and secreted OPN promotes T_FH cell differentiation.