Hsa_circ_0016070/micro‐340‐5p Axis Accelerates Pulmonary Arterial Hypertension Progression by Upregulating TWIST1 Transcription Via TCF4/β‐Catenin Complex

Interaction between Wnt/β-catenin signaling pathway and EMT pathway mediates the mechanism of sunitinib resistance in renal cell carcinoma

BACKGROUND

Targeted drugs are the main methods of RCC treatment. However, drug resistance is common in RCC patients, in-depth study of the drug-resistant mechanism is essential.

METHODS

We constructed sunitinib resistant and Twist overexpressed A498 cells, and studied its mechanisms in vitro and in vivo.

RESULTS

In cell research, we found that either sunitinib resistance or Twist overexpression can activate Wnt/β-catenin and EMT signaling pathway, and the sunitinib resistance may work through β-catenin/TWIST/TCF4 trimer. In zebrafish research, we confirmed the similarity of Twist overexpression and sunitinib resistance, and the promoting effect of Twist overexpression on drug resistance.

CONCLUSIONS

Sunitinib resistance and Twist overexpression can activate Wnt/β-catenin signaling pathway and EMT to promote the growth and metastasis of RCC cells.

Circular RNA: A new expectation for cardiovascular diseases

Circular RNA (circRNA) is a class of RNA with the 5' and 3' ends connected covalently to form a closed loop structure and characterized by high stability, conserved sequences and tissue specificity, which is caused by special reverse splicing methods. Currently, it has become a hot spot for research. With the discovery of its powerful regulatory functions and roles, the molecular mechanisms and future value of circRNA in participating in and regulating biological and pathological processes are becoming increasingly apparent. Among them is the increasing prevalence of cardiovascular diseases (CVDs). Many studies have elucidated that circRNA plays a crucial role in the development and progression of CVDs. Therefore, circRNA shows its advantages and brilliant expectations in the field of CVDs. In this review, we describe the biogenesis, bioinformatics detection and function of circRNA and discuss the role of circRNA and its effects on CVDs, including atherosclerosis, myocardial infarction, cardiac hypertrophy and heart failure, myocardial fibrosis, cardiac senescence, pulmonary hypertension, and diabetic cardiomyopathy by different mechanisms. That shows circRNA advantages and brilliant expectations in the field of CVDs.

Epigenetic regulation of programmed cell death in hypoxia-induced pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a severe progressive disease that may cause early right ventricular failure and eventual cardiac failure. The pathogenesis of PAH involves endothelial dysfunction, aberrant proliferation of pulmonary artery smooth muscle cells (PASMCs), and vascular fibrosis. Hypoxia has been shown to induce elevated secretion of vascular endothelial growth factor (VEGF), leading to the development of hypoxic PAH. However, the molecular mechanisms underlying hypoxic PAH remain incompletely understood. Programmed cell death (PCD) is a natural cell death and regulated by certain genes. Emerging evidence suggests that apoptotic resistance contributes to the development of PAH. Moreover, several novel types of PCD, such as autophagy, pyroptosis, and ferroptosis, have been reported to be involved in the development of PAH. Additionally, multiple diverse epigenetic mechanisms including RNA methylation, DNA methylation, histone modification, and the non-coding RNA molecule-mediated processes have been strongly linked to the development of PAH. These epigenetic modifications affect the expression of genes, which produce important changes in cellular biological processes, including PCD. Consequently, a better understanding of the PCD processes and epigenetic modification involved in PAH will provide novel, specific therapeutic strategies for diagnosis and treatment. In this review, we aim to discuss recent advances in epigenetic mechanisms and elucidate the role of epigenetic modifications in regulating PCD in hypoxia-induced PAH.

Linc-ROR drive adriamycin resistance by targeting AP-2α/Wnt/β-catenin axis in hepatocellular carcinoma

Adriamycin is widely used as a chemotherapeutic strategy for advanced hepatocellular carcinoma (HCC). However, the clinical response was disappointing because of the acquired drug resistance with long-term usage. Revealing the underlying mechanism could provide promising therapeutics for the drug-resistant patients. The recently identified linc-ROR (long intergenic non-protein-coding RNA, regulator of reprogramming) has been found to be an oncogene in various cancers, and it also demonstrated to mediate drug resistance and metastasis. We thereby wonder whether this lincRNA could mediate adriamycin chemoresistance in HCC. In this study, linc-ROR was found to be upregulated in adriamycin-resistant HCC cells. And its overexpression accelerated epithelial-mesenchymal transition (EMT) program and adriamycin resistance. Conversely, its silence suppressed EMT and made HCC cells sensitize to adriamycin in vitro and in vivo. Further investigation revealed that linc-ROR physically interacted with AP-2α, mediated its stability by a post-translational modification manner, and sequentially activated Wnt/β-catenin pathway. Furthermore, linc-ROR expression was positively associated with β-catenin expression in human clinical specimens. Taken together, linc-ROR promoted tumorigenesis and adriamycin resistance in HCC via a linc-ROR/AP-2α/Wnt/β-catenin axis, which could be developed as a potential therapeutic target for the adriamycin-resistant patients.

Circ-Ntrk2 acts as a miR-296-5p sponge to activate the TGF-β1/p38 MAPK pathway and promote pulmonary hypertension and vascular remodelling

BACKGROUND

Circular RNAs (circRNAs), a novel class of non-coding RNAs, play an important regulatory role in pulmonary arterial hypertension (PAH); however, the specific mechanism is rarely studied. In this study, we aimed to discover functional circRNAs and investigate their effects and mechanisms in hypoxia-induced pulmonary vascular remodelling, a core pathological change in PAH.

METHODS

RNA sequencing was used to illustrate the expression profile of circRNAs in hypoxic PAH. Bioinformatics, Sanger sequencing, and quantitative real-time PCR were used to identify the ring-forming characteristics of RNA and analyse its expression. Then, we established a hypoxia-induced PAH mouse model to evaluate circRNA function in PAH by echocardiography and hemodynamic measurements. Moreover, microRNA target gene database screening, fluorescence in situ hybridisation, luciferase reporter gene detection, and western blotting were used to explore the mechanism of circRNAs.

RESULTS

RNA sequencing identified 432 differentially expressed circRNAs in mouse hypoxic lung tissues. Our results indicated that circ-Ntrk2 is a stable cytoplasmic circRNA derived from Ntrk2 mRNA and frequently upregulated in hypoxic lung tissue. We further found that circ-Ntrk2 sponges miR-296-5p and miR-296-5p can bind to the 3'-untranslated region of transforming growth factor-β1 (TGF-β1) mRNA, thereby attenuating TGF-β1 translation. Through gene knockout or exogenous expression, we demonstrated that circ-Ntrk2 could promote PAH and vascular remodelling. Moreover, we verified that miR-296-5p overexpression alleviated pulmonary vascular remodelling and improved PAH through the TGF-β1/p38 MAPK pathway.

CONCLUSIONS

We identified a new circRNA (circ-Ntrk2) and explored its function and mechanism in PAH, thereby establishing potential targets for the diagnosis and treatment of PAH. Furthermore, our study contributes to the understanding of circRNA in relation to PAH.