KLF16 Downregulates the Expression of Tumor Suppressor Gene TGFBR3 to Promote Bladder Cancer Proliferation and Migration

ZFP36L1 controls KLF16 mRNA stability in vascular smooth muscle cells during restenosis after vascular injury

The RNA-binding zinc finger protein 36 (ZFP36) family participates in numerous physiological processes including transition and differentiation through post-transcriptional regulation. ZFP36L1 is a member of the ZFP36 family. This study aimed to evaluate the role of ZFP36L1 in restenosis. We found that the expression of ZFP36L1 was inhibited in VSMC-phenotypic transformation induced by TGF-β, PDGF-BB, and FBS and also in the rat carotid injury model. In addition, we found that the overexpression of ZFP36L1 inhibited the proliferation and migration of VSMCs and promoted the expression of VSMC contractile genes; whereas ZFP36L1 interference promoted the proliferation and migration of VSMCs and suppressed the expression of contractile genes. Furthermore, the RNA binding protein immunoprecipitation and double luciferase reporter gene experiments shows that ZFP36L1 regulates the phenotypic transformation of VSMCs through the posttranscriptional regulation of KLF16. Finally, our research results in the rat carotid balloon injury animal model further confirmed that ZFP36L1 regulates the phenotypic transformation of VSMCs through the posttranscriptional regulation of KLF16 and further plays a role in vascular injury and restenosis in vivo.

The kruppel-like factor (KLF) family, diseases, and physiological events

The Kruppel-Like Factor family of regulatory proteins, which has 18 members, is transcription factors. This family contains zinc finger proteins, regulates the activation and suppression of transcription, and binds to DNA, RNA, and proteins. Klfs related to the immune system are Klf1, Klf2, Klf3, Klf4, Klf6, and Klf14. Klfs related to adipose tissue development and/or glucose metabolism are Klf3, Klf7, Klf9, Klf10, Klf11, Klf14, Klf15, and Klf16. Klfs related to cancer are Klf3, Klf4, Klf5, Klf6, Klf7, Klf8, Klf9, Klf10, Klf11, Klf12, Klf13, Klf14, Klf16, and Klf17. Klfs related to the cardiovascular system are Klf4, Klf5, Klf10, Klf13, Klf14, and Klf15. Klfs related to the nervous system are Klf4, Klf7, Klf8, and Klf9. Klfs are associated with diseases such as carcinogenesis, oxidative stress, diabetes, liver fibrosis, thalassemia, and the metabolic syndrome. The aim of this review is to provide information about the relationship of Klfs with some diseases and physiological events and to guide future studies.

Integrated multiomics analysis of chromosome 19 miRNA cluster in bladder cancer

With 46 microRNAs (miRNAs) embedded tandemly over a distance of ~100 kb, chromosome 19 microRNA cluster (C19MC) is the largest miRNA cluster in the human genome. The C19MC is transcribed from a long noncoding genomic region and is usually expressed simultaneously at a higher level. Hence, we performed an integrative multiomics data analysis to examine C19MC regulation, expression patterns, and their impact on bladder cancer (BCa). We found that 43 members of C19MC were highly expressed in BCa. However, its co-localization with recurrent copy number variation (CNV) gain was not statistically significant to implicate its upregulation. It has been reported that C19MC expression is regulated by a well-established CpG island situated 17.6 kb upstream of the transcription start site, but we found that CpG probes at this island were hypomethylated, which was not statistically significant in the BCa cohort. In addition, the promoter region of C19MC is strongly regulated by a group of seven transcription factors (NR2F6, SREBF1, TBP, GATA3, GABPB1, ETV4, and ZNF444) and five chromatin modifiers (SMC3, KDMA1, EZH2, RAD21, and CHD7). Interestingly, these 12 genes were found to be overexpressed in BCa patients. Further, C19MC targeted 42 tumor suppressor (TS) genes that were downregulated, of which 15 were significantly correlated with patient survival. Our findings suggest that transcription factors and chromatin modifiers at the promoter region may regulate C19MC overexpression. The upregulated C19MC members, transcription regulators, and TS genes can be further exploited as potential diagnostic and prognostic indicators as well as for therapeutic management of BCa.

Recent advances in the understanding of urothelial tumorigenesis

INTRODUCTION

Patients with non-muscle-invasive bladder tumor suffer from disease recurrence following transurethral surgery even with intravesical pharmacotherapy, while muscle-invasive disease is often deadly. It is therefore critical to elucidate the underlying molecular mechanisms responsible for not only bladder tumor progression but also its tumorigenesis. Indeed, various molecules and/or signaling pathways have been suggested to contribute to the pathogenesis of bladder cancer.

AREAS COVERED

We summarize the progress during the last few years on the initiation or development, but not progression, of urothelial cancer. The clinical implications of these available data, including prognostic significance and possible application for the prevention of the recurrence of non-muscle-invasive bladder tumors, are also discussed.

EXPERT OPINION

Bladder cancer is a heterogeneous group of neoplasms. The establishment of personalized therapeutic options based on the molecular profile in each case should thus be considered. On that account, further accumulation of data on urothelial tumorigenesis is warranted to identify promising targets for the prevention of postoperative tumor recurrence or tumor development in otherwise high-risk patients.

Krüppel-like factors in tumors: Key regulators and therapeutic avenues

Krüppel-like factors (KLFs) are a group of DNA-binding transcriptional regulators with multiple essential functions in various cellular processes, including proliferation, migration, inflammation, and angiogenesis. The aberrant expression of KLFs is often found in tumor tissues and is essential for tumor development. At the molecular level, KLFs regulate multiple signaling pathways and mediate crosstalk among them. Some KLFs may also be molecular switches for specific biological signals, driving their transition from tumor suppressors to promoters. At the histological level, the abnormal expression of KLFs is closely associated with tumor cell stemness, proliferation, apoptosis, and alterations in the tumor microenvironment. Notably, the role of each KLF in tumors varies according to tumor type and different stages of tumor development rather than being invariant. In this review, we focus on the advances in the molecular biology of KLFs, particularly the regulations of several classical signaling pathways by these factors, and the critical role of KLFs in tumor development. We also highlight their strong potential as molecular targets in tumor therapy and suggest potential directions for clinical translational research.

SF3B4 promotes Twist1 expression and clear cell renal cell carcinoma progression by facilitating the export of KLF 16 mRNA from the nucleus to the cytoplasm

Splicing factor 3B subunit 4 (SF3B4) plays important functional roles not only in pre-mRNA splicing, but also in the regulation of transcription, translation, and cell signaling, and its dysregulation contributes to various diseases including Nager syndrome and tumorigenesis. However, the role of SF3B4 and underlying mechanisms in clear cell renal cell carcinoma (ccRCC) remain obscure. In the present study, we found that the expression of SF3B4 was significantly elevated in ccRCC tissues and negatively correlated with the overall survival of ccRCC patients. Upregulation of SF3B4 promotes migration and invasion of ccRCC cells in vitro and in vivo. The promoting effect of SF3B4 on cell migration and invasion is mediated by Twist1, a key transcription factor to mediate EMT. Interestingly, SF3B4, a component of the pre-mRNA spliceosome, is able to promote KLF16 expression by facilitating the transport of KLF16 mRNA into the cytoplasm. Mechanistically, SF3B4 promotes the export of KLF16 mRNA from the nucleus to the cytoplasm and thus enhances KLF16 expression, and in turn elevated KLF16 directly binds to the Twist1 promoter to activate its transcription, leading to EMT and ccRCC progression. Our findings provide evidence that the SF3B4-KLF16-Twist1 axis plays important functional roles in the development and progression of ccRCC, and manipulating this pathway may be a novel therapeutic target for the treatment of ccRCC.

CDKN3 Overcomes Bladder Cancer Cisplatin Resistance via LDHA-Dependent Glycolysis Reprogramming

Background

Aerobic glycolysis plays an important role in bladder cancer (BLCA) progression and chemoresistance. Cyclin-dependent kinase inhibitor-3 (CDKN3), a dual-specificity protein tyrosine phosphatase, has aberrant upregulation in multiple cancer types and is associated with tumorigenesis. However, the role of CDKN3 in BLCA progression and glycolysis has not been elucidated.

Purpose

In this study, we investigated the effect and underlying mechanisms of CDKN3 on bladder cancer chemoresistance.

Results

This study confirmed that CDKN3 was overexpressed in BLCA tissues and promoted proliferation and migration. Additionally, our results showed a CDKN3-dependent mechanism on chemoresistance; chemoresistance cells were transformed into chemosensitivity cells by CDKN3 knockdown. Additionally, we showed that CDKN3 knockdown decreased glycolysis by inhibiting LDHA expression in BLCA chemoresistance cells. The results also proved that LDHA was an important mediator of CDKN3-regulated BLCA resistance. LDHA overexpression reversed glycolysis inhibition and chemosensitivity induced by CDKN3 downregulation.

Conclusion

These data collectively identified a vital role of CDKN3 in glycolysis and chemoresistance by regulating LDHA expression in BLCA cells, providing a possible therapeutic strategy for treating BLCA.