BACE2 Promotes Bladder Cancer Chemoresistance Through Proteolytic Activation of JAG1‐Notch Signaling

RBCK1 promotes chemotherapy resistance in bladder carcinoma by targeting HLTF.

Bladder cancer remains highly prone to cisplatin resistance, which markedly limits therapeutic efficacy and contributes to poor clinical outcomes. Although dysregulation of E3 ubiquitin ligases has been implicated in tumor progression and drug resistance, the specific ligases that drive cisplatin resistance in bladder cancer and their underlying mechanisms remain incompletely defined. In this study, integrated analysis of public transcriptomic datasets identified RBCK1 as an aberrantly upregulated E3 ubiquitin ligase associated with malignant progression and cisplatin resistance in bladder cancer. Functional assays showed that RBCK1 promoted clonogenic survival and reduced cisplatin sensitivity in bladder cancer cells. Mechanistically, RBCK1 directly interacted with the helicase-like transcription factor HLTF and facilitated its ubiquitin-proteasome-dependent degradation, thereby decreasing HLTF protein stability. Loss of HLTF relieved suppression of the JAK2/STAT3 pathway and enhanced STAT3 activation. Rescue experiments further demonstrated that HLTF depletion attenuated the cisplatin-sensitizing effect induced by RBCK1 knockdown, whereas pharmacological inhibition of STAT3 with Stattic abrogated this resistance-restoring phenotype. Collectively, these findings identify an RBCK1-HLTF-JAK2/STAT3 regulatory axis that promotes cisplatin resistance in bladder cancer cells, and xenograft validation further supports the role of RBCK1 depletion in enhancing cisplatin response in vivo. Further clinical studies are warranted to determine the translational relevance of targeting this pathway in cisplatin-treated bladder cancer.

DUSP5 contributes to platinum resistance in ovarian cancer: single-cell discovery and functional validation

Background Platinum-based chemotherapy remains the cornerstone of ovarian cancer treatment, yet acquired resistance severely limits efficacy. Because platinum agents can also influence immunogenic cell death and tumor microenvironment (TME) remodeling, clarifying cellular pharmacological mechanisms of sensitivity and resistance within the ovarian cancer tumor ecosystem is important for understanding therapeutic failure. Methods We integrated single-cell RNA-seq from treatment-naïve and post-neoadjuvant chemotherapy ovarian tumors with bulk multi-omics cohorts to map epithelial tumor heterogeneity, transcriptional reprogramming, pathway activation, immune infiltration, and inferred cell–cell communication networks. DUSP5 was identified as a candidate regulator linked to stress-adaptive programs. Functional validation included qPCR, proliferation, migration, colony-formation, carboplatin dose-response, and xenograft assays following stable DUSP5 knockdown. Results Single-cell analysis revealed chemotherapy-associated epithelial states with enhanced stress, EMT, hypoxia, and inflammatory signatures. Elevated DUSP5 expression correlated with MAPK/JAK-STAT/TGF-β signaling, myeloid/stromal infiltration, and clinical outcome differences in independent cohorts. DUSP5 depletion suppressed proliferation and migration, amplified carboplatin-induced MAPK transcriptional responses and pro-apoptotic signaling (BAX/PUMA upregulation, BCL2 downregulation), reduced IC50 values in both OVCAR8 and SKOV3 cells, and significantly inhibited xenograft tumor growth. Conclusion DUSP5 may contribute to platinum response and resistance by linking tumor-intrinsic adaptive programs with TME-associated features in ovarian cancer. These findings support DUSP5 as a candidate biomarker and therapeutic target that warrants further mechanistic and clinical validation.

FOXD1 upregulates DARS2-mediated glycolysis to drive cisplatin resistance in bladder cancer.

BACKGROUND Chemotherapy remains the most effective systemic treatment for bladder cancer (BLCA), with cisplatin as the primary agent. However, the frequent development of cisplatin resistance limits its clinical efficacy. Forkhead box D1 (FOXD1) is implicated in BLCA progression, yet its role in mediating cisplatin resistance remains unexplored. METHODS FOXD1 expression and its correlation with patient prognosis in BLCA were analyzed using the TCGA database. Cisplatin-resistant BLCA cell lines (T24-R and HT-1376-R) were established by treatment with gradient concentrations of cisplatin. qRT-PCR and Western blot were performed to detect the expression levels of FOXD1, β-catenin, and Aspartyl-tRNA Synthetase 2 (DARS2). Cell viability, proliferation, cell cycle, and apoptosis were assessed using CCK-8, colony formation assays, and flow cytometry. Co-IP was performed to examine the interaction between FOXD1 and β-catenin. Glycolysis levels in BLCA cells were determined using specific assay kits. RESULTS FOXD1 was highly expressed in BLCA tissues and correlated with poor prognosis. Knockdown of FOXD1 inhibited proliferation and cell cycle progression, promoted apoptosis, and enhanced cisplatin sensitivity in T24-R cells, while reducing β-catenin nuclear translocation and DARS2 expression. Overexpression of FOXD1 exerted the opposite effects on HT-1376-R cells and increased DARS2 expression, which were reversed by β-catenin knockdown. Moreover, knockdown of TCFs/LEF suppressed DARS2 expression. DARS2 was enriched in the glycolysis pathway. Its overexpression promoted glycolysis, proliferation, and cell cycle progression, while inhibiting apoptosis and cisplatin sensitivity in HT-1376-R cells-effects were reversed by 2-DG. CONCLUSION FOXD1 facilitates β-catenin nuclear translocation and upregulates DARS2 to enhance glycolysis, thereby promoting cisplatin resistance in BLCA. These findings identify the FOXD1/β-catenin/DARS2 axis as a potential therapeutic target for overcoming cisplatin resistance in BLCA clinically.

DLGAP5 enhances chemotherapy resistance in pancreatic ductal adenocarcinoma by regulating glycolysis through MYC.

BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) is widely recognized as the most lethal malignancy of the digestive system. Its poor prognosis is largely attributed to a high degree of resistance to gemcitabine (GEM), highlighting the critical need to elucidate the underlying mechanisms of GEM resistance for effective therapeutic intervention. DLGAP5, a cell cycle-associated protein, has been implicated in PDAC progression; however, its potential role in regulating glycolysis and GEM resistance remains unclear. METHODS The expression level and prognostic significance of DLGAP5 in PDAC were evaluated using bioinformatics analysis and Western blotting. In vitro tumorigenic assays were conducted to assess the impact of DLGAP5 on cellular proliferation. Furthermore, the interactions between DLGAP5 and MYC or USP11 were investigated through biochemical assays, protein-protein interaction studies, and gene expression analyses. RESULTS Our findings demonstrate that DLGAP5 promotes glycolytic metabolism and confers resistance to GEM in PDAC. High DLGAP5 expression correlates with adverse clinical outcomes in PDAC patients. Mechanistically, DLGAP5 facilitates the deubiquitination of MYC via interaction with USP11, thereby enhancing MYC protein stability and promoting both GEM resistance and glycolytic activity. CONCLUSION DLGAP5 modulates MYC protein stability through the USP11-mediated deubiquitination pathway. Targeting the DLGAP5-USP11-MYC signaling axis may represent a promising therapeutic strategy to overcome GEM resistance in PDAC.

Targeting MEST using cobicistat as a therapeutic strategy for gastric cancer through suppressing NF-κB signaling

Background Gastric cancer (GC) constitutes a substantial global public health challenge, and the lack of tractable molecular targets limits therapeutic progress. Mesoderm-Specific Transcript (MEST) has been implicated in tumor-related signaling, yet its functional role and druggability in GC remain undefined. Methods The analyses of GC tissue microarrays and cohorts were performed to evaluate MEST expression and its clinical significance. CRISPR/Cas9-mediated MEST knockout was used to characterize its oncogenic functions in GC cells and xenograft models. Integrated RNA sequencing and pathway analysis was utilized to elucidate signaling pathways under the regulation of MEST. A structure-guided virtual screen combined with SPR binding and phenotypic assays were employed to discover small molecules targeting MEST. The therapeutic effects and mechanism of the lead compound were evaluated using GC cell lines, patient-derived organoids, cell-derived xenograft (CDX), and patient-derived xenograft (PDX) models. Methods MEST expression in GC tissues was elevated and linked to poor prognosis. Functionally, genetic ablation of MEST impaired GC cell proliferation, invasion, migration, and suppressed tumor growth in CDX models. Screening of approved-compound libraries identified cobicistat as a previously unrecognized high-affinity candidate MEST-inhibitory compound. Cobicistat suppressed tumor growth across a panel of preclinical GC models, including cell lines, organoids, CDX and PDX. Mechanistically, MEST may drive GC progression by activating the NF-κB pathway, whereas cobicistat may antagonize MEST binding and blocked NF-κB pathway. Conclusion MEST functions as a key oncoprotein driving GC progression via NF-κB activation. Cobicistat, a candidate MEST-inhibitory compound, exhibits favorable preclinical efficacy and safety, providing a promising candidate for targeted GC therapy.

Single-cell and spatial transcriptomics identify CAPG as a key driver of cisplatin resistance in bladder cancer