Circular RNA (circ)_0129047 upregulates bone morphogenetic protein receptor type 2 expression to inhibit lung adenocarcinoma progression by sponging microRNA (miR)-1206

miRNAs and exosomal miRNAs in lung cancer: New emerging players in tumor progression and therapy response

Non-coding RNAs have shown key roles in cancer and among them, short RNA molecules are known as microRNAs (miRNAs). These molecules have length less than 25 nucleotides and suppress translation and expression. The functional miRNAs are produced in cytoplasm. Lung cancer is a devastating disease that its mortality and morbidity have undergone an increase in recent years. Aggressive behavior leads to undesirable prognosis and tumors demonstrate abnormal proliferation and invasion. In the present review, miRNA functions in lung cancer is described. miRNAs reduce/increase proliferation and metastasis. They modulate cell death and proliferation. Overexpression of oncogenic miRNAs facilitates drug resistance and radio-resistance in lung cancer. Tumor microenvironment components including macrophages and cancer-associated fibroblasts demonstrate interactions with miRNAs in lung cancer. Other factors such as HIF-1α, lncRNAs and circRNAs modulate miRNA expression. miRNAs have also value in the diagnosis of lung cancer. Understanding such interactions can pave the way for developing novel therapeutics in near future for lung cancer patients.

hsa_circ_0129047 Upregulates LYVE1 to Inhibit Hepatocellular Carcinoma Progression by Sponging miR-492

Compelling evidence indicates the regulatory role of circular RNAs in cancers, including hepatocellular carcinoma (HCC). Our study aimed to elucidate the regulatory function of circ_0129047 in HCC progression. A reverse transcription-quantitative polymeric chain reaction was conducted to detect the expression of circ_0129047, lymphatic vessel endothelial hyaluronan receptor-1 (LYVE1), and miR-492 in HCC tissues and cells. The characteristics of circ_0129047 were determined by evaluating the nuclear and cytoplasmic fractions and by RNase R digestion assays. The cell counting kit-8 assay, scratch wound, and transwell invasion assays were used to examine the effects of circ_0129047 overexpression, miR-492 mimic, and LYVE1 overexpression on the proliferation, migration, and invasion abilities of HCC cells in vitro. A mouse xenograft model was also established. The relationship between miR-492 and circ_0129047 or LYVE1 was clarified using luciferase reporter and Argonaute-2 RNA immunoprecipitation assays. We found that circ_0129047 and LYVE1 were poorly expressed in HCC tissues and cells, whereas miR-492 was upregulated. Overexpression of circ_0129047 inhibits HCC cell proliferation, migration, and invasion and delays in vivo tumor growth. Furthermore, circ_0129047 sponged miR-492, and 3'UTR LYVE1 was a direct target of miR-492. Additionally, LYVE1 overexpression reduced the oncogenic activity of the miR-492 mimic, whereas the miR-492 mimic abolished the antimigratory, antiproliferative, and anti-invasive effects of circ_0129047 overexpression in HCC cells. These data suggest that circ_0129047 exerts a tumor-suppressive role in HCC by sponging miR-492 away from LYVE1 and that the circ_0129047/miR-492/LYVE1 axis may be a promising target for HCC treatment.

Circ_0043256 upregulates KLF2 expression by absorbing miR-1206 to suppress the tumorigenesis of lung cancer

BACKGROUND

Circular RNAs (circRNAs) have been reported to play roles in lung cancer development. The purpose of this work was to explore the function and mechanism of circ_0043256 in lung cancer tumorigenesis.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot were used for the detection of the levels of genes and proteins. Cell growth, angiogenesis ability, migration, and invasion were analyzed by using 5-ethynyl-2'-deoxyuridine (EdU) assay, flow cytometry, tube formation assay, transwell assay, and murine xenograft model, respectively. The target between miR-1206 and circ_0043256 or Krüppel-like factor 2 (KLF2) was verified by dual-luciferase reporter assay.

RESULTS

Circ_0043256 was a stable circRNA, which was found to be decreased in lung cancer tissues and cells. Functionally, forced expression of circ_0043256 suppressed lung cancer cell growth, angiopoiesis, migration, and invasion. Mechanistically, circ_0043256 directly bound to miR-1206 and miR-1206 targeted KLF2, circ_0043256 could regulate KLF2 expression via absorbing miR-1206. Rescue assay showed that miR-1206 overexpression reversed the anticancer effects of circ_0043256 on lung cancer cells. Moreover, inhibition of miR-1206 could suppress the malignant phenotypes of lung cancer cells, which was attenuated by KLF2 knockdown. Pre-clinically, lentivirus-mediated circ_0043256 overexpression impeded lung cancer growth in nude mice.

CONCLUSION

Forced expression of circ_0043256 could impede the tumorigenesis of lung cancer via miR-1206/KLF2 axis, indicating a potential therapeutic approach for lung cancer.

Functions of the bone morphogenetic protein signaling pathway through non-coding RNAs

Bone morphogenetic proteins (BMPs) are proteins of the transforming growth factor-β (TGF-β) family, which plays an important role in the formation of skeletal and cartilage tissue and their regeneration. BMPs play a key role in the formation of new blood vessels and promote the migration, proliferation, and differentiation of mesenchymal stem cells (MSCs) into chondroblasts and osteoblasts. It is known that malfunction of BMPs signaling can cause a disease state. Epigenetic regulation of expression plays a key role in the control of many cellular processes. Important participants in this regulation are non-coding RNAs (ncRNAs), which are RNA molecules that are not translated into proteins. The best known of these are microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). In addition, the results of many studies make it possible to establish an unambiguous functional relationship between these ncRNAs. Being involved in the regulation of a large number of target genes responsible for the life of the cell, miRNAs, lncRNAs, and circRNAs are essential for the normal development and functioning of the body, and the violation of their functions accompanies the development of many pathophysiological processes including oncogenesis. In the present review, we discuss different insights into the regulation of BMPs signaling pathway by miRNAs, lncRNAs and circRNAs governed.