Silencing of circ_0078607 prevents development of gastric cancer and inactivates the ERK1/2/AKT pathway through the miR-188-3p/RAP1B axis

The role of circRNAs in regulation of drug resistance in ovarian cancer

Ovarian cancer is one of the female reproductive system tumors. Chemotherapy is used for advanced ovarian cancer patients; however, drug resistance is a pivotal cause of chemotherapeutic failure. Hence, it is critical to explore the molecular mechanisms of drug resistance of ovarian cancer cells and to ameliorate chemoresistance. Noncoding RNAs (ncRNAs) have been identified to critically participate in drug sensitivity in a variety of human cancers, including ovarian cancer. Among ncRNAs, circRNAs sponge miRNAs and prevent miRNAs from regulation of their target mRNAs. CircRNAs can interact with DNA or proteins to modulate gene expression. In this review, we briefly describe the biological functions of circRNAs in the development and progression of ovarian cancer. Moreover, we discuss the underneath regulatory molecular mechanisms of circRNAs on governing drug resistance in ovarian cancer. Furthermore, we mention the novel strategies to overcome drug resistance via targeting circRNAs in ovarian cancer. Due to that circRNAs play a key role in modulation of drug resistance in ovarian cancer, targeting circRNAs could be a novel approach for attenuation of chemoresistance in ovarian cancer.

Sinomenine regulates circTRPM7-related pathway to inhibit gastric cancer cell growth and metastasis

Sinomenine has been found to have antitumor effects in a variety of cancers, including gastric cancer. Circular RNA (circRNA) is an important regulator of gastric cancer progression. However, it is not known whether Sinomenine mediates gastric cancer processes by regulating circRNA-related pathways. Quantitative real-time PCR was used to measure the expression of circTRPM7, microRNA-145-5p (miR-145-5p), and pre-B-cell leukemia homeobox 3 (PBX3). MTT assay, colony formation assay, EdU assay, transwell assay, wound-healing assay, and flow cytometry were used to detect cell proliferation, migration, invasion, and apoptosis. The expression of related proteins was detected by Western blot. Mechanically, the interaction of miR-145-5p with circTRPM7/PBX3 was validated by dual-luciferase reporter assay and RIP assay. Our study showed that circTRPM7 expression was reduced in Sinomenine-treated gastric cancer cells. Moreover, overexpression of circTRPM7 upregulated the growth and metastasis of Sinomenine-treated gastric cancer cells. CircTRPM7 could sponge miR-145-5p, and miR-145-5p reversed the effect of circTRPM7 on the growth and metastasis of Sinomenine-treated gastric cancer cells. PBX3 was the target of miR-145-5p, and knockdown of PBX3 could restore the in-miR-145-5p promotion effect on the malignant behavior of Sinomenine-treated gastric cancer cells. To sum up, our data indicated that Sinomenine played an antitumor role in gastric cancer cells via circTRPM7/miR-145-5p/PBX3 axis.

Antitumor activity of miR-188-3p in gastric cancer is achieved by targeting CBL expression and inactivating the AKT/mTOR signaling

BACKGROUND

Altered miR-188-3p expression has been observed in various human cancers.

AIM

To investigate the miR-188-3p expression, its roles, and underlying molecular events in gastric cancer.

METHODS

Fifty gastric cancer and paired normal tissues were collected to analyze miR-188-3p and CBL expression. Normal and gastric cancer cells were used to manipulate miR-188-3p and CBL expression through different assays. The relationship between miR-188-3p and CBL was predicted bioinformatically and confirmed using a luciferase gene reporter assay. A Kaplan-Meier analysis was used to associate miR-188-3p or CBL expression with patient survival. A nude mouse tumor cell xenograft assay was used to confirm the in vitro data.

RESULTS

MiR-188-3p was found to be lower in the plasma of gastric cancer patients, tissues, and cell lines compared to their healthy counterparts. It was associated with overall survival of gastric cancer patients (P < 0.001), tumor differentiation (P < 0.001), lymph node metastasis (P = 0.033), tumor node metastasis stage (I/II vs III/IV, P = 0.024), and American Joint Committee on Cancer stage (I/II vs III/IV, P = 0.03). Transfection with miR-188-3p mimics reduced tumor cell growth and invasion while inducing apoptosis and autophagy. CBL was identified as a direct target of miR-188-3p, with its expression antagonizing the effects of miR-188-3p on gastric cancer (GC) cell proliferation by inducing tumor cell apoptosis and autophagy through the inactivation of the Akt/mTOR signaling pathway. The in vivo data confirmed antitumor activity via CBL downregulation in gastric cancer.

CONCLUSION

The current data provides ex vivo, in vitro, and in vivo evidence that miR-188-3p acts as a tumor suppressor gene or possesses antitumor activity in GC.

Circ_0111277 suppresses trophoblast cell proliferation, angiogenesis, migration, invasion and EMT via regulating miR-188-3p/GRHL2 axis

PROBLEM

Preeclampsia (PE) is the main factor threatening the life of primipara. Defective migration and invasion of trophoblast cells was one of the causes of PE. Circ_0111277 had been reported to be related to the development of PE, but the mechanism of its effect on trophoblast cells needed further study.

METHOD OF STUDY

The expression of circ_0111277, microRNA-188-3p (miR-188-3p) and grainyhead-like 2 (GRHL2) mRNA were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell Counting Kit-8 (CCK-8) assay, 5-Ethynyl-20-deoxyuridine (EdU) and colony formation assay were used to examine cell proliferation ability. Tube formation and transwell assay were performed to assess the angiogenesis and metastasis ability of cells. Western blot was applied to measure the levels of epithelial-mesenchymal transition (EMT)-related proteins (E-cadherin and Vimentin) and GRHL2 protein. The relationship between miR-188-3p and circ_0111277 or GRHL2 was verified by the dual luciferase reporter experiment.

RESULTS

Circ_0111277 and GRHL2 were elevated, and miR-188-3p was declined in PE patients. Overexpression of circ_0111277 could inhibit the proliferation, angiogenesis, migration, invasion and EMT of trophoblast cells (HTR-8/Svneo). Circ_0111277 was the molecular sponge of miR-188-3p. MiR-188-3p up-regulation could reduce the inhibition of HTR-8/Svneo cell growth caused by overexpression of circ_0111277. GRHL2 was a target gene of miR-188-3p, and GRHL2 silencing relieved the adverse effects of miR-188-3p inhibitors on HTR-8/Svneo. In general, circ_0111277 up-regulated GRHL2 expression through sponge miR-188-3p.

CONCLUSION

Highly expressed circ_0111277 up-regulated the expression of GRHL2 through sponge miR-188-3p, thereby inhibiting trophoblast cells function, which suggested a new molecular mechanism for the pathogenesis of PE.

Circular RNAs as diagnostic biomarkers for gastric cancer: A comprehensive update from emerging functions to clinical significances

The incidence and mortality of gastric cancer ranks as a fouth leading cause of cancer death worldwide, especially in East Asia. Due to the lack of specific early-stage symptoms, the majority of patients in most developing nations are diagnosed at an advanced stage. Therefore, it is urgent to find more sensitive and reliable biomarkers for gastric cancer screening and diagnosis. Circular RNAs (circRNAs), a novel type of RNAs with covalently closed loops, are becoming a latest hot spot in the field of. In recent years, a great deal of research has demonstrated that abnormal expression of circRNAs was associated with the development of gastric cancer, and suggested that circRNA might serve as a potential biomarker for gastric cancer diagnosis. In this review, we summarize the structural characteristics, formation mechanism and biological function of circRNAs, and elucidate research progress and existing problems in early screening of gastric cancer.

Plasma circRNAs as Biomarkers in Cancer

The incidence and mortality of cancer are increasing each year. At present, the sensitivity and specificity of the blood biomarkers that were used in clinical practice are low, which make the detection rate of cancer decrease. With advances in bioinformatics and technology, some non-coding RNA as biomarkers can be easily detected through some traditional and new technologies. Circular RNAs (circRNAs) are non-coding RNAs, that is, they do not encode proteins, and have important regulatory functions. CircRNAs can remain stable in bodily fluids, such as in saliva, blood, urine, and especially plasma. The difference in the expression of plasma circRNAs between cancer patients and normal people may suggest that plasma circRNAs may play an important role in the occurrence and development of cancer. In this review, we summarized the clinical effect of plasma circRNAs in several high-incidence cancers. CircRNAs may be effective biomarkers for tumour diagnosis, treatment selection and prognosis evaluation.