METI: deep profiling of tumor ecosystems by integrating cell morphology and spatial transcriptomics.

Recent advances in spatial transcriptomics (ST) techniques provide valuable insights into cellular interactions within the tumor microenvironment (TME). However, most analytical tools lack consideration of histological features and rely on matched single-cell RNA sequencing data, limiting their effectiveness in TME studies. To address this, we introduce the Morphology-Enhanced Spatial Transcriptome Analysis Integrator (METI), an end-to-end framework that maps cancer cells and TME components, stratifies cell types and states, and analyzes cell co-localization. By integrating spatial transcriptomics, cell morphology, and curated gene signatures, METI enhances our understanding of the molecular landscape and cellular interactions within the tissue. We evaluate the performance of METI on ST data generated from various tumor tissues, including gastric, lung, and bladder cancers, as well as premalignant tissues. We also conduct a quantitative comparison of METI with existing clustering and cell deconvolution tools, demonstrating METI's robust and consistent performance.

SUMO E3 ligase MUL1 inhibits lymph node metastasis of bladder cancer by mediating mitochondrial HSPA9 translocation.

Lymph node (LN) metastasis is the dominant cause of death in bladder cancer (BCa) patients, but the underlying mechanism remains largely unknown. In recent years, accumulating studies have confirmed that bidirectional mitochondria-nucleus communication is essential for sustaining multiple function of mitochondria. However, little has been studied regarding whether and how the translocation of mitochondrial proteins is involved in LN metastasis. In this study, we first identified that the SUMO E3 ligase MUL1 was significantly downregulated in LN-metastatic BCa tissues and correlated with a good prognosis. Mechanistically, MUL1 SUMOylated HSPA9 at the K612 residue, leading to HSPA9 export from mitochondria and interaction with SUZ12 and in the nucleus. Consequently, MUL1 induced the ubiquitination-mediated degradation of SUZ12 and EZH2 and induced downstream STAT3 pathway inhibition in a HSPA9-dependent manner. Importantly, mutation of HSPA9 SUMO-conjugation motifs limited the translocation of mitochondrial HSPA9 and blocked the HSPA9-SUZ12 and HSPA9-EZH2 interactions. With mutation of the HSPA9 K612 site, the suppressive role of MUL1 overexpression was lost in BCa cells. Further in vitro and in vivo assays revealed that MUL1 inhibits the metastasis and proliferation of BCa cells. Overall, our study reveals a novel function and molecular mechanism of SUMO E3 ligases in LN metastasis.

Role of Forkhead Box P3 in IFNγ-Mediated PD-L1 Expression and Bladder Cancer Epithelial-to-Mesenchymal Transition.

Antagonism of the PD-1/PD-L1 axis is a critical therapeutic strategy for patients with advanced bladder cancer. IFNγ functions as a key regulator of PD-L1 in both immune as well as cancer cells. Forkhead box P3 (FOXP3) is a transcription factor synonymous in T regulatory cell function but with increasingly described functions in cancer cells. Here, we investigated the relationship between FOXP3 and PD-L1 in bladder cancer. We showed that FOXP3 is critical in the ability for IFNγ to activate PD-L1 in bladder cancer cells. FOXP3 can bind to the PD-L1 promoter and induces a gene program that leads to regulation of multiple immune-related genes and genes involved in epithelial-to-mesenchymal transition (EMT). Using in vitro and in vivo human and murine models, we showed that FOXP3 can influence bladder cancer EMT as well as promote cancer metastases. Furthermore, FOXP3 may be a convergent factor for multiple activators of PD-L1, including the chemotherapeutic drug cisplatin. SIGNIFICANCE: Historically a key transcription factor driving T regulatory cell function, FOXP3 has an increasingly recognized role in cancer cells. In bladder cancer, we defined a novel mechanism whereby FOXP3 mediates the activation of the immune checkpoint PD-L1 by the cytokine IFNγ. We also showed that FOXP3 induces other immune checkpoints as well as genes involved in EMT, promoting immune resistance and cancer metastases.

Amino-truncated NOV expression and its correlation with clinicopathologic features, prognosis, metastasis, and chemoresistance in bladder cancer.

Nephroblastoma, an overexpressed gene (NOV) protein, plays an important role in proliferation, differentiation, angiogenesis, adhesion, invasion and tumorigenesis, but the function of amino-truncated NOV is different. This study is to investigate the role of amino-truncated NOV in the progression of bladder cancer. Using immunohistochemistry and Western blot analysis, we detected the amino-truncated NOV in bladder cancer, and statistical analysis was performed to estimate the association between the expression of amino-truncated NOV and the patient's prognosis by SPSS 19.0. With transduction of amino-truncated NOV, we evaluated alteration for proliferation, migration, invasion and chemoresistance in bladder cancer cells, as well as some proteins related to Wnt/ß-catenin pathway and epithelial-mesenchymal transition. The truncated variant of the NOV protein was located in a nucleus other than the cytoplasm and highly expressed in bladder cancer, which was also linked to higher pathological grade and positive lymph node metastasis as well as recurrence. The exact sequence of this truncated protein was confirmed, and it was a 26-kDa splicing. The truncated NOV protein found in bladder cancer was cut at the 187th amino acid of the full-length protein. It was also involved in bladder cancer progression and chemoresistance through a mechanism involving epithelial-mesenchymal transition (EMT) and the Wnt/ß-catenin signaling pathway. Our findings provide experimental evidence that the nuclear NOV protein expression is a potential biomarker in the prognostic evaluation of bladder cancer and enhanced amino-truncated NOV expression is potentially important for bladder cancer cell invasion, metastasis and chemoresistance during progression.

Cryptotanshinone Inhibits Bladder Cancer Cell Malignant Progression in a Lipopolysaccharide-Induced Inflammatory Microenvironment through NLRP3 Inhibition.

Background: Bladder cancer (BC) is one of the most common malignancies of the urogenital system. This study assessed the nucleotide-binding oligomerization domain and leucine-rich repeat and pyrin domain-containing protein 3 (NLRP3) in BC as well as the effects of cryptotanshinone on changes in BC malignant behaviors and NLRP3 expression under a lipopolysaccharide (LPS)-induced inflammatory microenvironment. Methods: BC tissue specimens from 62 patients were collected for immunohistochemical detection of NLRP3 protein. BC and normal urothelial cell lines were cultured for the detection of NLRP3 mRNA and protein. Then, BC cells were pretreated with LPS to mimic the inflammatory tumor microenvironment. Next, these cells were incubated with a low or high dose of cryptotanshinone to assess its effects on tumor cell malignant behaviors as well as transfected with NLRP3 cDNA to confirm the role of NLRP3 in BC cells in vitro. Results: High NLRP3 expression was associated with larger tumor diameters (>2 cm), muscle invasion, and metastasis. The levels of NLRP3 mRNA and protein were greater in BC cells than in normal urothelial cells. LPS pretreatment significantly promoted NLRP3 and inflammatory cytokine expression in BC cells, and induced cell viability, migration, and invasion. However, cryptotanshinone was able to reduce the LPS-induced increase of NLRP3 and inflammatory cytokine expression as well as the BC cell malignant progression. NLRP3 overexpression using NLRP3 cDNA further promoted BC cell malignant progression after LPS stimulation and reversed cryptotanshinone-reduced LPS-induced BC cell malignant behaviors. Conclusion: NLRP3 might possess oncogenic activity in BC, and the antitumor activity of cryptotanshinone in BC in vitro might be related to its inhibition of NLRP3 expression.

The MEF2A/SNHG16/miR-425-5p/NOTCH2 axis induces gemcitabine resistance by inhibiting ferroptosis in the starving bladder tumor microenvironment.

Gemcitabine resistance is one of the leading causes of bladder cancer (BCa) recurrence and progression. The dysregulation of ferroptosis is involved in this process; however, the underlying mechanisms remain unclear. In the current study, we found a prominent increase in long non-coding RNA (lncRNA) small nucleolar RNA host gene 16 (SNHG16) in tumor samples, which was related to advanced tumor grade and poor prognosis. SNHG16 is overexpressed in the starving tumor microenvironment (STME) and induces gemcitabine resistance by inhibiting ferroptosis in BCa. SNHG16 knockdown promotes ferroptosis and increases chemosensitivity to gemcitabine. Mechanistically, the transcription factor MEF2A was markedly upregulated in the STME, facilitating SNHG16 expression. SNHG16 acts as a competing endogenous RNA that sponges miR-425-5p and promotes NOTCH2 expression. SNHG16/miR-425-5p/NOTCH2 is demonstrated, for the first time, to suppress ferroptosis by inducing SLC7A11 and GPX4 expression in vitro and in vivo. Upregulation of miR-425-5p reverses NOTCH2-mediated inhibition of ferroptosis, thereby mitigating gemcitabine resistance. In conclusion, these findings reveal that the STME-activated MEF2A/SNHG16/miR-425-5p/NOTCH2 axis induces gemcitabine resistance by inhibiting ferroptosis and implicate SNHG16 as a potential therapeutic target for chemoresistance.

Patient-derived bladder cancer organoids show stable transcript expression along cultivation.

INTRODUCTION: Bladder cancer (BC) is a prevalent malignancy with high recurrence rates. Patient-derived bladder cancer organoids (BCO) pose as a promising approach in both, disease modeling and individualized treatment screening. The aim of this study was to investigate the transcriptomic plasticity in BCOs as a function of cultivation times to define ideal time periods for the applications envisioned. METHODS: Tumor samples of three patients with pathologically confirmed non-muscle invasive and muscle-invasive bladder cancer were included in this study and expanded as BCOs. RNA expression was investigated at different time periods of cells in culture using differential gene expression for overall transcript expression and quantitative real-time PCR (qRT-PCR) for pathological relevant markers. RESULTS: Differential gene expression of the BCO lines was investigated across passages 1-4, in passages 5-9 and above 9, respectively. Analysis of the entire transcriptome of the respective BCO lines revealed consistent profiles without significant alterations throughout the cultivation and expansion procedure. Notably, key transcripts like TP53, PIK3CA, BRCA1, among others, exhibited stable expression levels in the quantitative RNA analysis during the cultivation period. CONCLUSION: The robust transcriptome during BCO cultivation advocates for the use of earlier passages of BCOs in personalized medicine providing a time-efficient drug screening option to accelerate the counseling of patients' treatment options. Higher passages of BCOs still hold the potential in topics demanding for expanded cell masses such as medical device development and others.

PD-L1 expression and its correlation with tumor biomarkers in Chinese urothelial bladder cancer.

Data on prevalence of programmed death ligand-1 (PD-L1) expression and its correlation with tumor biomarkers in Chinese patients with muscle-invasive urothelial bladder cancer (MIUBC) are scarce. We investigated the prevalence of PD-L1 expression, PD-L1 expression in tumor cells (TC) and immune cells (IC), and its correlation with tumor biomarkers (CD8+ T cells and tumor mutation burden [TMB]) in Chinese patients with newly diagnosed MIUBC (NCT03433924). Of 248 patients enrolled, 229 with PD-L1 data available were analysed. High PD-L1 expression (≥ 25% of TC or IC with PD-L1 expression) was observed in 120 (52.4%) patients. 59 cases showed positive staining in ≥ 25% of TC, and 82 cases had positive staining in ≥ 25% of IC. High expression of CD8+ T cell and TMB (> 10 mutations/megabase) was observed in 44.5% and 54.1% patients, respectively. A positive correlation was observed between percentage of TC with membrane PD-L1 positivity and CD8+ T cells (0.34; P < 0.001) and between IC with membrane PD-L1 positivity and CD8+ T cells (0.44; P < 0.001). There is high prevalence of PD-L1 expression in Chinese patients with MIUBC, suggesting that a sizable subset of patients could benefit from immunotherapy. The correlation of PD-L1 expression with tumor biomarkers provide clues for mechanisms underlying the effects of biomarkers for predicting efficacy.

Clinicopathological and molecular characterization of extra-appendix goblet cell adenocarcinomas.

Goblet cell adenocarcinoma (GCA) is a distinctive type of endocrine-exocrine mixed tumor, exhibiting intermediate morphological features between neuroendocrine tumor and adenocarcinoma. It predominantly arises in the appendix, but primary extra-appendiceal GCA is extremely rare. Here, we presented six cases of primary extra-appendiceal GCA from 2016 to 2022. Notably, one case was originating in the bladder which was the first report of primary GCA to occur outside the digestive tract. The tumors frequently displayed variable goblet cell morphology, characterized by cytoplasmic mucin accumulation and basally located nucleus. Low-grade components typically exhibited glandular or clustered patterns without prominent fibrotic responses. High-grade components demonstrated cribriform, cluster and single-file arrangement accompanied by marked fibrous reactions. Immunohistochemically, the tumors showed positivity for both neuroendocrine markers（synaptophysin, chromogranin A, CD56 ）and adenoids markers（CDX-2, CK20）. Next-generation sequencing revealed the most prevalent mutated genes within GCAs were TP53. Due to their morphological and immunohistochemical similarities to primary appendiceal GCA counterparts, we propose a distinct category for extra-appendiceal Goblet cell adenocarcinoma.

MyD88 Signaling Accompanied by Microbiota Changes Supports Urinary Bladder Carcinogenesis.

Urinary bladder cancer (BC) inflicts a significant impairment of life quality and poses a high mortality risk. Schistosoma haematobium infection can cause BC, and the urinary microbiota of BC patients differs from healthy controls. Importantly, intravesical instillation of the bacterium Bacillus Calmette-Guerin stands as the foremost therapy for non-muscle invasive BC. Hence, studying the receptors and signaling molecules orchestrating bacterial recognition and the cellular response in the context of BC is of paramount importance. Thus, we challenged Toll-like receptor 4 (Tlr4) and myeloid differentiation factor 88 (Myd88) knock-out (KO) mice with N-butyl-N-(4-hydroxylbutyl)-nitrosamine (BBN), a well-known urinary bladder carcinogen. Gut microbiota, gene expression, and urinary bladder pathology were followed. Acute exposure to BBN did not reveal a difference in bladder pathology despite differences in the animal's ability to recognize and react to bacteria. However, chronic treatment resulted in reduced cancer invasiveness among Myd88KO mice while the absence of functional Tlr4 did not influence BC development or progression. These differences correlate with a heightened abundance of the Faecalibaculum genus and the lowest microbial diversity observed among Myd88KO mice. The presented data underscore the important role of microbiota composition and MyD88-mediated signaling during bladder carcinogenesis.

Evaluation of androgen receptor and androgen receptor splice-variant 7 in bladder cancer; a novel approach into an ancient topic.

PURPOSE: The contribution of androgen receptors (AR) on bladder cancer has been demonstrated in pre-clinical studies, however in clinical studies, only the canonical AR (AR-FL) protein was measured by immunohistochemistry and conflicting results were obtained. To get better insight into the alterations of AR signalling, we used western blotting (WB) method and simultaneously measured both mRNA and protein levels of AR-FL and AR-V7. METHODS: 23 naive non-muscle invasive bladder cancer patients and 12 healthy individuals were included. AR-FL protein, AR-FL mRNA, AR-V7 protein and AR-V7 mRNA levels were quantitatively measured by WB and qRT-PCR. RESULTS: While AR-FL protein and AR-V7 mRNA were significantly higher in bladder cancer, AR-FL mRNA and AR-V7 protein were lower. AR-V7 mRNA level was higher in patients with tumour size over 3 cm and AR-FL protein was higher in single tumours (p < 0,005). The small sampling size and the inclusion of only male participants were the main limitations. CONCLUSIONS: The increase of AR-FL protein in bladder cancer supports the contribution of the AR pathway in bladder cancer. The presence of high AR-FL protein despite low mRNA levels may be due to a disruption in post-transcriptional regulatory mechanisms. AR-V7 was demonstrated for the first time in bladder tissue and found significantly different in bladder cancer tissues. Our study reached new and valuable findings and will shed light on the studies that aim to clarify the role of the AR pathway in bladder cancer.

ZDHHC9-mediated Bip/GRP78 S-palmitoylation inhibits unfolded protein response and promotes bladder cancer progression.

Recent studies have highlighted palmitoylation, a novel protein post-translational modification, as a key player in various signaling pathways that contribute to tumorigenesis and drug resistance. Despite this, its role in bladder cancer (BCa) development remains inadequately understood. In this study, ZDHHC9 emerged as a significantly upregulated oncogene in BCa. Functionally, ZDHHC9 knockdown markedly inhibited tumor proliferation, promoted tumor cell apoptosis, and enhanced the efficacy of gemcitabine (GEM) and cisplatin (CDDP). Mechanistically, SP1 was found to transcriptionally activate ZDHHC9 expression. ZDHHC9 subsequently bound to and palmitoylated the Bip protein at cysteine 420 (Cys420), thereby inhibiting the unfolded protein response (UPR). This palmitoylation at Cys420 enhanced Bip's protein stability and preserved its localization within the endoplasmic reticulum (ER). ZDHHC9 might become a novel therapeutic target for BCa and could also contribute to combination therapy with GEM and CDDP.

ASF1B is an essential prognostic indicator linked to the growth and resistance characteristics of bladder cancer.

BACKGROUND: Anti-silencing function 1 (ASF1) is a conserved histone H3-H4 chaperone protein. ASF1B (Anti-Silencing Function 1B Histone Chaperone), a paralog of ASF1, is involved in tumor metabolism and growth. The regulatory network of ASF1B in cancer is intricate and remains inadequately explored. The objective of this study was to examine the biological role of ASF1B in bladder cancer (BC). METHODS: The presence of ASF1B in BC was examined using The Cancer Genome Atlas (TCGA) and Cancer Cell Line Encyclopedia (CCLE) databases. In addition, a correlation analysis was performed to evaluate the association between the BC pathway scores and ASF1B. ASF1B expression in BC cells was detected using western blott and RT-PCR. Several investigations were conducted, both within and outside of a living organism, to confirm the involvement of ASF1B in the regulation of biological processes in BC cells. RESULTS: Our examination of the database indicates that ASF1B exhibits significant expression levels in BC cells and is potentially strongly associated with the growth of BC cells and the repair of DNA. The expression of ASF1B in BC cells was found to be significantly elevated, as indicated by the results of western blot and RT-PCR. The findings of the cell plate cloning test, edu analysis, flow cytometry, and transwell experiments demonstrated that the inhibition of ASF1B greatly impeded the proliferation and migration of BC cells. After establishing drug-resistant BC cell lines in a lab, suppressing ASF1B gene expression led to a notable reduction in BC cells' resistance to cisplatin. Confirmation was achieved by flow cytometry and western blott assays. Our in vivo findings demonstrated that the suppression of ASF1B resulted in an amelioration of the pathological condition, a decrease in resistance to cisplatin, and an inhibition of the growth of BC in mice.

Nuclear translocation of ISG15 regulated by PPP2R2B inhibits cisplatin resistance of bladder cancer.

Cisplatin resistance is a major challenge for systemic therapy against advanced bladder cancer (BC). Little information is available on the regulation of cisplatin resistance and the underlying mechanisms require elucidation. Here, we detected that downregulation of the tumor suppressor, PPP2R2B (a serine/threonine protein phosphatase 2 A regulatory subunit), in BC promoted cell proliferation and migration. What's more, low PPP2R2B expression was correlated with cisplatin resistance. In vitro and in vivo experiments verified that PPP2R2B could promote BC sensitivity to cisplatin. In terms of mechanism, we identified a novel function of PPP2R2B as a nucleocytoplasmic transport molecule. PPP2R2B promoted ISG15 entry into the nucleus by mediating binding of IPO5 with ISG15. Nuclear translocation of ISG15 inhibited DNA repair, further increasing ISG15 expression through activation of the STING pathway. Besides, PPP2R2B was down-regulated by SUV39H1-mediated histone 3 lysine 9 trimethylation, which could be restored by the SUV39H1-specific inhibitor, chaetocin. Our data suggest that PPP2R2B expression level is a potential biomarker for chemotherapy response and that chemotherapy in combination with chaetocin may be a feasible treatment strategy for patients with BC.

LncRNA MEG3 Inhibits the Epithelial-mesenchymal Transition of Bladder Cancer Cells through the Snail/E-cadherin Axis.

OBJECTIVE: This study aimed to investigate the role of the long noncoding RNA (lncRNA) maternally expressed gene 3 (MEG3) in the epithelial-mesenchymal transition (EMT) of bladder cancer cells and the potential mechanisms. METHODS: Cell invasion, migration, and wound healing assays were conducted to assess the effects of MEG3 on the invasive and migratory capabilities of bladder cancer cells. The expression levels of E-cadherin were measured using Western blotting, RT-qPCR, and dual luciferase reporter assays. RNA immunoprecipitation and pull-down assays were performed to investigate the interactions between MEG3 and its downstream targets. RESULTS: MEG3 suppressed the invasion and migration of bladder cancer cells and modulated the transcription of E-cadherin. The binding of MEG3 to the zinc finger region of the transcription factor Snail prevented its ability to transcriptionally repress E-cadherin. Additionally, MEG3 suppressed the phosphorylation of extracellular regulated protein kinase (ERK), c-Jun N-terminal kinase (JNK), and P38, thereby decreasing the expression of Snail and stimulating the expression of E-cadherin. CONCLUSION: MEG3 plays a vital role in suppressing the EMT in bladder cancer cells, indicating its potential as a promising therapeutic target for the treatment of bladder cancer.

Gambogic Acid Improves Cisplatin Resistance of Bladder Cancer Cells through the Epithelial-Mesenchymal Transition Pathway Mediated by the miR-205-5p/ZEB1 Axis.

OBJECTIVE: Bladder cancer (BC) is primarily treated with cisplatin-based chemotherapy, but the development of cisplatin resistance often leads to BC recurrence. This study is focused on assessing the potential of gambogic acid (GA) in mitigating BC cells' cisplatin resistance, along with an analysis of the underlying mechanism involved. METHODS: Cisplatin was administered to human bladder transitional cell carcinoma cells (T24) at various concentration gradients to induce cisplatin-resistant (T24-DDP) cells. Several experimental groups were set: T24 group, T24-DDP group, T24-DDP+DDP group, T24-DDP+GA group, T24-DDP+DDP+GA group, T24-DDP+DDP+GA+miR-NC group, and T24-DDP+DDP+GA+miR-205-5p inhibitor group. The cell counting kit-8 (CCK-8) assay, Transwell migration assay, and scratch assay were respectively carried out for assessment of cell proliferation, invasion, and migration. Western blot analysis was conducted for detection of the protein expression of E-cadherin, ZEB1, Vimentin, N-cadherin, LRP, MRP, and P-gp in the cells, while the relative expression level of miR-205-5p was determined by qRT-PCR. RESULTS: In comparison with the T24-DDP group, cells in the T24-DDP+GA group showed enhanced sensitivity to cisplatin. Furthermore, as indicated by CCK-8 assay, GA improved T24-DDP cells' sensitivity to cisplatin, potentiated the effects of cisplatin, and exerted an inhibitory effect on the invasion, proliferation, as well as migration of T24-DDP cells. Through Western blot analysis, GA was revealed to significantly inhibit the expression of N-cadherin, E-cadherin, and Vimentin, as well as that of cisplatin-resistant proteins MRP, P-gp, and LRP in BC cells. In addition, shown by further experiments, GA promoted miR-205-5p expression and simultaneously inhibited ZEB1 expression within the cells. CONCLUSION: GA alleviates BC cells' cisplatin resistance through the epithelial-mesenchymal transition pathway mediated by the miR-205-5p/ZEB1 axis.

The Prognostic Hub Gene POLE2 Promotes BLCA Cell Growth via the PI3K/AKT Signaling Pathway.

BACKGROUND: BLCA is a common urothelial malignancy characterized by a high recurrence rate. Despite its prevalence, the molecular mechanisms underlying its development remain unclear. AIMS: This study aimed to explore new prognostic biomarkers and investigate the underlying mechanism of bladder cancer (BLCA). OBJECTIVE: The objective of this study is to identify key prognostic biomarkers for BLCA and to elucidate their roles in the disease. METHODS: We first collected the overlapping DEGs from GSE42089 and TCGA-BLCA samples for the subsequent weighted gene co-expression network analysis (WGCNA) to find a key module. Then, key module genes were analyzed by the MCODE algorithm, prognostic risk model, expression and immunohistochemical staining to identify the prognostic hub gene. Finally, the hub gene was subjected to clinical feature analysis, as well as cellular function assays. RESULTS: In WGCNA on 1037 overlapping genes, the blue module was the key module. After a series of bioinformatics analyses, POLE2 was identified as a prognostic hub gene in BLCA from potential genes (TROAP, POLE2, ANLN, and E2F8). POLE2 level was increased in BLCA and related to different clinical features of BLCA patients. Cellular assays showed that si-POLE2 inhibited BLCA proliferation, and si-POLE2+ 740Y-P in BLCA cells up-regulated the PI3K and AKT protein levels. CONCLUSION: In conclusion, POLE2 was identified to be a promising prognostic biomarker as an oncogene in BLCA. It was also found that POLE2 exerts a promoting function by the PI3K/AKT signaling pathway in BLCA.

PTBP1-mediated biogenesis of circATIC promotes progression and cisplatin resistance of bladder cancer.

Background: Cisplatin (DDP) based combination chemotherapy is a vital method for the treatment of bladder cancer (BLca). Chemoresistance easily occurs in the course of cisplatin chemotherapy, which is one of the important reasons for the unfavorable prognosis of BLca patients. Circular RNAs (circRNAs) are widely recognized for their role in the development and advancement of BLca. Nevertheless, the precise role of circRNAs in DDP resistance for BLca remains unclear. Methods: To study the properties of circATIC, sanger sequencing, agarose gel electrophoresis and treatment with RNase R/Actinomycin D were utilized. RT-qPCR assay was utilized to assess the expression levels of circRNA, miRNA and mRNA in BLca tissues and cells. Functional experiments were conducted to assess the function of circATIC in BLca progression and chemosensitivity in vitro. Various techniques such as FISH, Dual-luciferase reporter assay, TRAP, RNA digestion assay, RIP and ChIRP assay were used to investigate the relationships between PTBP1, circATIC, miR-1247-5p and RCC2. Orthotopic bladder cancer model, xenograft subcutaneous tumor model and xenograft lung metastasis tumor model were performed to indicate the function and mechanism of circATIC in BLca progression and chemosensitivity in vivo. Results: In our study, we observed that circATIC expression was significantly enhanced in BLca tissues and cells and DDP resistant cells. Patients with higher circATIC expression have larger tumor diameter, higher incidence of postoperative metastasis and lower overall survival rate. Further experiments showed that circATIC accelerated BLca cell growth and metastasis and induced DDP resistance. Mechanistically, alternative splicing enzyme PTBP1 mediated the synthesis of circATIC. circATIC could enhance RCC2 mRNA stability via sponging miR-1247-5p or constructing a circATIC/LIN28A/RCC2 RNA-protein ternary complex. Finally, circATIC promotes RCC2 expression to enhance Epithelial-Mesenchymal Transition (EMT) progression and activate JNK signal pathway, thus strengthening DDP resistance in BLca cells. Conclusion: Our study demonstrated that circATIC promoted BLca progression and DDP resistance, and could serve as a potential target for BLca treatment.