Background: Docetaxel resistance represents a significant obstacle in the treatment of prostate cancer. The intricate interplay between cytokine signalling pathways and transcriptional control mechanisms in cancer cells contributes to chemotherapeutic resistance, yet the underlying molecular determinants remain only partially understood. This study elucidated a novel resistance mechanism mediated by the autocrine interaction of interleukin-11 (IL-11) and its receptor interleukin-11 receptor subunit alpha(IL-11RA), culminating in activation of the JAK1/STAT4 signalling axis and subsequent transcriptional upregulation of the oncogene c-MYC. Methods: Single-cell secretion profiling of prostate cancer organoid was analyzed to determine cytokine production profiles associated with docetaxel resistance.Analysis of the expression pattern of downstream receptor IL-11RA and enrichment of signal pathway to clarify the potential autocrine mechanism of IL-11.Next, chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq) was performed to detect the nuclear localization and DNA-binding patterns of phosphorylated STAT4 (pSTAT4). Coimmunoprecipitation and reporter assays were utilized to assess interaction between pSTAT4 and the cotranscription factor CREB-binding protein (CBP) as well as their role in c-MYC transcriptional activity. Results: Autocrine secretion of IL-11 was markedly increased in docetaxel-resistant prostate cancer cells. IL-11 stimulation resulted in robust activation of JAK1/STAT4 signalling. Upon activation, pSTAT4 translocated to the nucleus and associated with CBP at the c-MYC promoter region, amplifying its transcriptional activity. Inhibition of the IL-11/IL-11RA interaction or disruption of the JAK1/STAT4 pathway significantly reduced pSTAT4 nuclear entry and its binding to CBP, leading to downregulation of c-MYC expression and restoration of docetaxel sensitivity. Conclusion: Our findings identify an autocrine loop of IL-11/IL-11RA that confers docetaxel resistance through the JAK1/STAT4 pathway. The pSTAT4-CBP interaction serves as a critical enhancer of c-MYC transcriptional activity in prostate cancer cells. Targeting this signalling axis presents a potential therapeutic strategy to overcome docetaxel resistance in advanced prostate cancer. Graphical

Background: This study comprehensively investigates the association between the expression of nicotinamide N-methyltransferase (NNMT) and clinical outcomes of urothelial bladder cancer (UBC), as well as the molecular mechanisms by which NNMT in cancer-associated fibroblast (CAF) modulates tumor progression and immunotherapy resistance in UBC. Methods: Single-cell transcriptomic analyses, immunohistochemical and immunofluorescence assays were performed on bladder cancer samples to validate the relationship between NNMT expression and clinical outcomes. A series of experiments, including chromatin immunoprecipitation assay, liquid chromatography tandem mass spectrometry assay, and CRISPR‒Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated protein 9) knockout, together with in vivo models, have been established to determine the molecular functions of NNMT in CAFs in UBC. Results: We demonstrated that elevated expression of the nicotinamide adenine dinucleotide (NAD⁺) metabolism enzyme NNMT in CAFs (NNMT⁺ CAFs) was significantly associated with non-response to programmed death-ligand 1 (PD-L1) blockade immunotherapy in patients with UBC and predicted the unfavorable prognosis of UBC in two independent large cohorts. Targeting NNMT using the inhibitor 5-Amino-1-methylquinolinium iodide significantly reduced tumor growth and enhanced the apoptotic effects of the anti-PD-L1 antibody in UBC mouse models. Mechanistically, NNMT⁺ CAFs recruit tumor-associated macrophages via epigenetic reprogramming of serum amyloid A (SAA) to drive tumor cell proliferation and confer resistance to programmed death-1/PD-L1 blockade immunotherapy. Conclusions: NNMT⁺ CAFs were significantly associated with non-response to PD-L1 blockade immunotherapy in patients with UBC. Elevated NNMT, specifically in CAFs, upregulates SAA expression and enhances the recruitment and differentiation of macrophages in the tumor microenvironment, thereby directly or indirectly promoting tumor progression and conferring resistance to immunotherapies in bladder cancer.

Metastasis is the major cause of prostate cancer (PCa)‐related mortality. Epithelial‐mesenchymal transition (EMT) is a vital characteristic feature that empowers cancer cells to adapt and survive at the beginning of metastasis. Therefore, it is essential to identify the regulatory mechanism of EMT in metastatic prostate cancer (mPCa) and to develop a novel therapy to block PCa metastasis. Here, we discovered a novel PCa metastasis oncogene, DEP domain containing 1B (DEPDC1B), which was positively correlated with the metastasis status, high Gleason score, advanced tumor stage, and poor prognosis. Functional assays revealed that DEPDC1B enhanced the migration, invasion, and proliferation of PCa cells in vitro and promoted tumor metastasis and growth in vivo. Mechanistic investigations clarified that DEPDC1B induced EMT and enhanced proliferation by binding to Rac1 and enhancing the Rac1‐PAK1 pathway. This DEPDC1B‐mediated oncogenic effect was reversed by a Rac1‐GTP inhibitor or Rac1 knockdown. In conclusion, we discover that the DEPDC1B‐Rac1‐PAK1 signaling pathway may serve as a multipotent target for clinical intervention in mPCa.

The link between carcinogen exposure and cancer immunogenicity is unclear. Single exposure to 12-dimethylbenz[a]anthracene (DMBA) at puberty accelerated spontaneous breast carcinogenesis in mouse mammary tumor virus-polyoma middle tumor-antigen transgenic (MMTV-PyMT^tg or PyMT) and MMTV-Her2/neu^tg (Her2) mice. Paradoxically, DMBA-treated PyMT and Her2 animals were protected from metastasis. CD8⁺ T cells significantly infiltrated DMBA-exposed breast cancers. CD8⁺ T cell depletion resulted in severe lung and liver metastasis in DMBA-treated PyMT mice. Besides increasing tumor mutational burden, DMBA exposure up-regulated Chemokine (C-C motif) ligand 21 (CCL21) in cancer cells and heightened antigen presentation. CCL21 injection suppressed breast cancer growth, and CCL21 receptor deletion attenuated T cell immunity against cancer metastasis in DMBA-treated PyMT animals. CCL21 expression correlated with increased mutational burden and cytolytic activity across human cancers. Higher CCL21 levels correlated with increased CD8⁺ T cell infiltrates in human breast cancer and predicted lower breast cancer distant recurrence rate. Collectively, carcinogen exposure induces immune-activating factors within cancer cells that promote CD8⁺ T cell immunity against metastasis.

Background: Bone metastasis is a principal cause of mortality in patients with prostate cancer (PCa). Increasing evidence indicates that high expression of stromal interaction molecule 1 (STIM1)-mediated store-operated calcium entry (SOCE) significantly activates the calcium (Ca²⁺) signaling pathway and is involved in multiple steps of bone metastasis in PCa. However, the regulatory mechanism and target therapy of STIM1 is poorly defined. Methods: Liquid chromatography-mass spectrometry analysis was performed to identify tetraspanin 18 (TSPAN18) as a binding protein of STIM1. Co-IP assay was carried out to explore the mechanism by which TSPAN18 inhibits STIM1 degradation. The biological function of TSPAN18 in bone metastasis of PCa was further investigated in vitro and in vivo models. Result: We identified that STIM1 directly interacted with TSPAN18, and TSPAN18 competitively inhibited E3 ligase tripartite motif containing 32 (TRIM32)-mediated STIM1 ubiquitination and degradation, leading to increasing STIM1 protein stability. Furthermore, TSPAN18 significantly stimulated Ca²⁺ influx in an STIM1-dependent manner, and then markedly accelerated PCa cells migration and invasion in vitro and bone metastasis in vivo. Clinically, overexpression of TSPAN18 was positively associated with STIM1 protein expression, bone metastasis and poor prognosis in PCa. Conclusion: Taken together, this work discovers a novel STIM1 regulative mechanism that TSPAN18 protects STIM1 from TRIM32-mediated ubiquitination, and enhances bone metastasis of PCa by activating the STIM1-Ca²⁺ signaling axis, suggesting that TSPAN18 may be an attractive therapeutic target for blocking bone metastasis in PCa.

Cancer-associated fibroblasts (CAFs) are a critical component of the tumor microenvironment, being implicated in enhancing tumor growth and fostering drug resistance. Nonetheless, the mechanisms underlying their function in prostate cancer (PCa) remain incompletely understood, which is essential for devising effective therapeutic strategies. The main objective of this study was to explore the mechanisms by which CAFs mediate PCa growth and chemoresistance. We validated through data analysis and experimentation that CAFs significantly impact PCa cell proliferation and chemoresistance. Subsequently, we conducted a comprehensive proteomic analysis of the conditioned media from CAFs and PCa cells and identified angiopoietin-like protein 4 (ANGPTL4) as a key factor. We employed ELISA and multiplex immunofluorescence assays, all of which indicated that ANGPTL4 was primarily secreted by CAFs.Next, we conducted metabolomics analysis, GST pull-down assays, Co-IP, and other experiments to explore the specific molecular mechanisms of ANGPTL4 and its precise effects on PCa cells. Through drug screening, we identified Quercetin 3-O-(6'-galactopyranosyl)-β-D-galactopyranoside (QGGP) as an effective inhibitor of CAFs function. Finally, we thoroughly assessed the therapeutic potential of QGGP both as a monotherapy and in combination with docetaxel in PCa cells RESULTS: We discovered that the extracrine factor ANGPTL4 is primarily expressed in CAFs in PCa. When ANGPTL4 binds to IQ motif-containing GTPase-activating protein 1 (IQGAP1) on the PCa cell membrane, it activates the Raf-MEK-ERK-PGC1α axis, promoting mitochondrial biogenesis and OXPHOS metabolism, and thereby facilitating PCa growth and chemoresistance. Furthermore, virtual and functional screening strategies identified QGGP as a specific inhibitor of IQGAP1 that promotes its degradation. Combined with docetaxel treatment, QGGP can reverse the effects of CAFs and improve the responsiveness of PCa to chemotherapy. This study uncovers a paracrine mechanism of chemoresistance in PCa and proposes that targeting the stroma could be a therapeutic choice.