circNUDT21 promotes bladder cancer progression by modulating the miR-16-1-3p/MDM2/p53 axis

CircSEPT9 promotes breast cancer progression by regulating PTBP3 expression via sponging miR-625-5p

BACKGROUND

Breast cancer (BC) is a common malignancy which threatens the health of women. Circular RNAs (circRNAs) are critical factors in multiple cancers, including BC. The aim of this experiment was to investigate the molecular mechanisms of circRNA Septin 9 (circSEPT9) in the progression of BC.

METHODS

CircSEPT9, microRNA-625-5p (miR-625-5p) and polypyrimidine tract-binding protein 3 (PTBP3) levels were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Western blot was performed to detect the protein levels of PTBP3, E-cadherin and vimentin. Cell counting kit-8 assay (CCK8) and thymidine analog 5-ethynyl-2'-deoxyuridine (EDU) was utilized for proliferation examination. Flow cytometry was conducted to measure apoptosis. Transwell assay and wound healing assay to investigate the migration of BC cells. Glucose uptake and lactate production were determined by specific kits. Additionally, dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were utilized to verify the interaction. A murine xenograft model was established to investigate the function of circSEPT9 in BC in vivo.

RESULTS

Overexpression of circSEPT9 was found in BC tissues and cells. Silencing circSEPT9 impeded BC cell proliferation, migration, epithelial-mesenchymal transition (EMT) and glycolytic metabolism but facilitated cell apoptosis in vitro. Meanwhile, circSEPT9 knockdown constrained tumor growth in vivo. MiR-625-5p was targeted by circSEPT9. The influence of silencing circSEPT9 on BC cell function was regained by miR-625-5p inhibitor. Furthermore, miR-625-5p regulated BC cell malignant phenotypes via downregulating PTBP3.

CONCLUSION

circSEPT9 contributed to the malignant progression of BC by up-regulating PTBP3 via sponging miR-625-5p.

CircFSCN1 induces tumor progression and triggers epithelial-mesenchymal transition in bladder cancer through augmentation of MDM2-mediated p53 silencing

BACKGROUND

Compelling evidences indicated that circular RNA (circRNA) was a novel class of non-coding RNA that played critical and distinct roles in various human cancers. Their roles and underlying mechanisms, however, in bladder cancer (BC) remained largely unknown.

METHODS

A novel circRNA derived from oncogene FSCN1, namely circFSCN1, was selected from a microarray analysis. The phenotypic alterations were assessed with functional experiments in vitro and in vivo. RNA immunoprecipitation, RNA pull-down, luciferase reporter assay, and rescue experiments were sequentially proceeded to clarify the interactions among circFSCN1, miR-145-5p, MDM2, and p53.

RESULTS

We observed that the expression of circFSCN1 was elevated in BC cell lines and tissues. Next, we validated the fundamental properties of circFSCN1. In the meanwhile, we noticed that elevated circFSCN1 level, pathological T stage, and tumor grade were identified as independent factors associated with cancer-specific survivals of patients with BC，as determined by univariate and multivariable COX regression analyses. Phenotype studies demonstrated the promoting effects of circFSCN1 on the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of BC cells. Mechanistically, we elucidated that circFSCN1, primarily localized in the cytoplasm, upregulated the expression of MDM2, a well-known inhibitor of p53, by directly binding to miR-145-5p.

CONCLUSIONS

Elevated circFSCN1 induces tumor progression and EMT in BC via enhancing MDM2-mediated silencing of p53 by sponging miR-145-5p. Targeting circFSCN1, a novel identified target, may be conducive in impeding BC progression and providing survival benefits for patients with BC.

The role of E3 ubiquitin ligases and deubiquitinases in bladder cancer development and immunotherapy

Bladder cancer is one of the common malignant urothelial tumors. Post-translational modification (PTMs), including ubiquitination, acetylation, methylation, and phosphorylation, have been revealed to participate in bladder cancer initiation and progression. Ubiquitination is the common PTM, which is conducted by E1 ubiquitin-activating enzyme, E2 ubiquitin-conjugating enzyme and E3 ubiquitin-protein ligase. E3 ubiquitin ligases play a key role in bladder oncogenesis and progression and drug resistance in bladder cancer. Therefore, in this review, we summarize current knowledge regarding the functions of E3 ubiquitin ligases in bladder cancer development. Moreover, we provide the evidence of E3 ubiquitin ligases in regulation of immunotherapy in bladder cancer. Furthermore, we mention the multiple compounds that target E3 ubiquitin ligases to improve the therapy efficacy of bladder cancer. We hope our review can stimulate researchers and clinicians to investigate whether and how targeting E3 ubiquitin ligases acts a novel strategy for bladder cancer therapy.

CircHGS enhances the progression of bladder cancer by regulating the miR-513a-5p/VEGFC axis and activating the AKT/mTOR signaling pathway

Bladder cancer (BCa) is a malignant tumor that occurs in the bladder mucosa with high mortality. Circular RNAs (circRNAs), as newly discovered noncoding RNAs, are associated with the occurrence and development of BCa. However, the effects of circRNAs in BCa have not been fully elucidated. Through the GEO (Gene Expression Omnibus) database, an abnormally expressed circular RNA, circHGS (hsa_circ_0004721), was first identified in BCa. qRT - PCR was performed to measure the expression of circHGS in BCa tissues and cells. The intracellular localization of circHGS was detected by nucleocytoplasmic separation experiment and fluorescence in situ hybridization assay. In vitro experiments were conducted to detect the effects of circHGS on cell cycle, proliferation, migration and invasion. The correlations between miR-513a-5p and circHGS or VEGFC were confirmed by dual-luciferase reporter assay, qRT - PCR and western blot. The role of circHGS in vivo was verified by xenograft tumor mice model. In this study, we clarified the roles and potential mechanism of circHGS in BCa. CircHGS, originating from the HGS gene, is upregulated in BCa tissues compared to normal tissues. Moreover, the expression of circHGS in BCa was positively associated with tumor grade and pathological T stage. Functionally, silencing of circHGS apparently suppressed cell cycle, proliferation, migration and invasion, but circHGS overexpression showed the opposite result. In vivo experiments also suggested that knockdown of circHGS suppressed tumor growth. Mechanistically, circHGS functions as a sponge of miR-513a-5p to elevate VEGFC expression and activate the AKT/mTOR signaling pathway, ultimately promoting BCa progression. Our findings indicated that circHGS promotes BCa progression via the miR-513a-5p/VEGFC/AKT/mTOR pathway and can be a promising therapeutic target of BCa.

PABPN1 regulates mRNA alternative polyadenylation to inhibit bladder cancer progression

BACKGROUND

About 10-20% of patients with bladder cancer (BC) progress to muscle-invasive diseases, of which the underlying key molecular events have yet to be addressed.

RESULTS

Here, we identified poly(A) binding protein nuclear 1 (PABPN1), a general factor of alternative polyadenylation (APA), was downregulated in BC. Overexpression and knockdown of PABPN1 significantly decreased and increased BC aggressiveness, respectively. Mechanistically, we provide evidence that the preference of PABPN1-bound polyadenylation signals (PASs) depends on the relative location between canonical and non-canonical PASs. PABPN1 shapes inputs converging on Wnt signaling, cell cycle, and lipid biosynthesis.

CONCLUSIONS

Together, these findings provide insights into how PABPN1-mediated APA regulation contributes to BC progression, and suggest that pharmacological targeting PABPN1 might have therapeutic potential in patients with BC.

UBE2J1 knockdown promotes cell apoptosis in endometrial cancer via regulating PI3K/AKT and MDM2/p53 signaling

Emerging evidence has demonstrated that ubiquitin conjugating enzyme E2 J1 (UBE2J1) exerts pivotal function in many cancers. UBE2J1 was reported to be dysregulated in endometrial cancer (EC). This study was designed to further investigate the regulatory character and mechanism of UBE2J1 in EC. Bioinformatic tools and databases were used to analyze gene expression pattern and gene expression correlation in EC tissues, and the prognosis of EC patients. Gene expression was evaluated by reverse-transcription quantitative polymerase chain reaction. Western blot was used for protein level detection. In vitro cell apoptosis was detected by flow cytometry analyses and TUNEL assays. In vivo cell apoptosis was evaluated by detecting Bax and Bcl-2 expression in tumor tissues via immunohistochemical and western blot analyses. In this study, UBE2J1 knockdown promoted cell apoptosis in EC cells and in mouse models of EC. PI3K and AKT expression is positively correlated with UBE2J1 level and is related to poor prognosis of EC patients. UBE2J1 knockdown repressed the PI3K/AKT pathway both in vitro and in vivo. UBE2J1 downregulation decreased MDM2 expression, but increased p53 expression. MDM2 overexpression reverses the promotion of UBE2J1 knockdown on cell apoptosis in EC. Overall, UBE2J1 knockdown induces cell apoptosis in EC by inactivating the PI3K/AKT signaling and suppressing the MDM2/p53 signaling.

Identify Potential Urine Biomarkers for Bladder Cancer Prognosis Using NGS Data Analysis and Experimental Validation

Bladder cancer (BC) is one of the most often reported malignancies globally, with a high recurrence rate and associated morbidity and mortality, especially in advanced BC. There has been a surge in the number of molecular targets revealed for BC prognosis and treatment. However, there is still a great need to discover novel biomarkers. Consequently, the current study investigated biomarkers that might indicate the progression of bladder cancer. In this study, bioinformatics analysis was done on a single GEO dataset, and TCGA-BLCA information was connected with differentially expressed genes (DEGs). The levels of mRNA and protein expression were validated using qRT-PCR. According to our findings, CRYAB, ECM1, ALDOB, AOC, GPX3, IGFBP7, AQP2, LASS2, TMEM176A, GALNT1, and LASS2 were highly enriched in cell division, identical protein binding, and developmental process in bladder cancer patients. In addition, among the highly differentiated genes, ECM1, GALNT1, LASS2, and GPX3 showed significant molecular alterations in BC, which are crucial for marker identification. Moreover, the mRNA, CNVs, and protein levels of ECM1, GALNT1, LASS2, and GPX3 were significantly increased in BC patients. Our predictions and analysis studies stated that these four genes act as urine biomarkers and played a crucial role in disease prognosis and the therapeutic process of bladder cancer. Our outcomes showed that these four novel urine biomarkers have the potential to provide innovative diagnostics, early predictions, and disease targets, ultimately improving the BC patient's prognosis.

Circular RNA Controls Tumor Occurrence and Development via Cell Cycle Regulation

Circular RNAs (circRNAs) participate in the occurrence and development of various diseases through different mechanisms, such as by acting as a microRNA (miRNA) sponge, interacting with RNA-binding proteins, and regulating gene transcription and protein translation. For example, the abnormal expression of specific circRNAs in tumor cells can alter key regulatory factors and the cell cycle network, resulting in cell cycle disorders and the development and metastasis of tumors. Here, we summarize the mechanisms involved in the circRNA-mediated processes that lead to uncontrolled cell cycle and tumor cell proliferation. Extensive studies investigating the abnormal expression of circRNAs in different cancer types have been conducted. The unique characteristics of circRNAs and their ability to regulate the cell cycle through diverse mechanisms is extremely valuable in tumor diagnosis, treatment, and prognosis. Our review may assist in further understanding the circRNA-mediated regulation of the cell cycle in tumors and provide insights for research on circRNA-based therapeutic strategies and biological diagnosis for cancer.

NEAT1 variant 1 weakens the genome-wide effect of miR-3122 on blocking H3K79me3 in bladder cancer

Nuclear-enriched abundant transcript 1 (NEAT1) is one of the most well-studied long non-coding RNAs (lncRNAs) in multiple human carcinoma. Two distinct variants of NEAT1, however, are never illuminated their specific functions and mechanisms underlying carcinogenesis. In this study, biotin-labelled NEAT1 variants were generated to incubate with cell lysate of bladder cancer cell T24 cells, and fished a batch of RNA substances. Here, we observed that NEAT1.1 (the short transcript) could capture 122 microRNAs (miRNAs), 36 small nucleolar RNAs (snoRNAs), 55 lncRNAs and 38 mRNAs while NEAT1.2 (the long transcript) could obtain 142 miRNAs, 51 snoRNAs, 72 lncRNAs and 41 mRNAs. Furthermore, we also found that the distinctions of RNA binding substances between these two variants were mainly expressed in nucleus rather than cytoplasm. GO analysis indicated that these non-coding RNAs governed histone modification, nucleosome assembly and chromosome organization. We picked up miRNA miR-3122, which substantially interacted with NEAT1.1, and found that histone H3K79me3 was reduced in bladder cancer T24, BIU-87 and EJ-1 cells after miR-3122 overexpression, and rescued by NEAT1.1 additional compensation. Nonetheless, we failed to find that miR-3122 could interfere with expression of H3K79 methyltransferase disruptor of telomeric silencing-1 like (DOT1L). Interestingly, we harvested histone 3 fished by biotin-labelled miR-3122, and validated this intercrossing using RNA immunoprecipitation. Taken together, we demonstrated that NEAT1.1 weakened the effect of miR-3122 on H3K79me3 suppression in bladder cancer.