MiRNA-4537 functions as a tumor suppressor in gastric cancer and increases the radiosensitivity of gastric cancer cells

Circ_LDLR promotes the progression of papillary thyroid carcinoma by regulating miR-1294/HMGB3 axis

Circular RNAs (circRNAs) have been found to be associated with the development and progression of cancers including papillary thyroid carcinoma (PTC). Circ_LDLR has been reported to be highly expressed in PTC, but its underlying mechanism of action has not been fully elucidated. This study aimed to investigate the role of circ_LDLR in PTC. The expression of circ_LDLR, miR-1294 and high mobility group box (HMGB) 3 was detected by quantitative real-time polymerase chain reaction (qRT-PCR). CCK-8 assay and transwell assays were employed to value cell viability, invasion and migration abilities. Western blot assay was to detect HMGB3 protein expression. Luciferase reporter gene and pull down assay were used to validate the interaction between miR-1294 and HMGB3 or circ_LDLR. Circ_LDLR showed high expression levels in PTC tissues and cells and knockdown of it inhibited the growth, invasion, and migration of PTC cells. In addition, miR-1294 was considered as a downstream target of circ_LDLR, and inhibition of miR-1294 partially reversed the inhibitory effects of circ_LDLR knockdown on PTC cells growth, invasion, and migration. More importantly, HMGB3 was identified as a downstream target of miR-1294. Our findings suggest circ_LDLR may plays a promoting role in PTC by downregulating miR-1294 and upregulating HMGB3 expression. Therefore, circ_LDLR may serve as a valuable prognostic biomarker and therapeutic target for PTC.

Non-coding RNAs in radiotherapy resistance: Roles and therapeutic implications in gastrointestinal cancer

Radiotherapy has become an indispensable and conventional means for patients with advanced solid tumors including gastrointestinal cancer. However, innate or acquired radiotherapy resistance remains a significant challenge and greatly limits the therapeutic effect, which results in cancer relapse and poor prognosis. Therefore, it is an urgent need to identify novel biomarkers and therapeutic targets for clarify the biological characteristics and mechanism of radiotherapy resistance. Recently, lots of studies have revealed that non-coding RNAs (ncRNAs) are the potential indicators and regulators of radiotherapy resistance via the mediation of various targets/pathways in different cancers. These findings may serve as a potential therapeutic strategy to overcome radiotherapy resistance. In this review, we will shed light on the recent findings regarding the functions and regulatory mechanisms of ncRNAs following radiotherapy, and comprehensively discuss their potential as biomarkers and therapeutic targets in radiotherapy resistance of gastrointestinal cancer.

Investigations into the impact of non-coding RNA on the sensitivity of gastric cancer to radiotherapy

Non-coding RNAs (ncRNAs) are a newly discovered functional RNA different from messenger RNA, which can participate in regulating the occurrence and development of tumors. More and more research results show that ncRNAs can participate in the regulation of gastric cancer (GC) radiotherapy response, and its mechanism may be related to its effect on DNA damage repair, gastric cancer cell stemness, cell apoptosis, activation of epidermal growth factor receptor signaling pathway, etc. This article summarizes the relevant mechanisms of ncRNAs regulating the response to radiotherapy in gastric cancer, which will be directly important for the introduction of ncRNAs particularly microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) into clinical medicine as biomarkers and therapeutic targets.

Successful Palliative Radiotherapy for Malignant Cardiac Obstruction Caused by Gastric Cancer

Gastric cancer is a common malignancy and some patients are diagnosed with an unresectable stage of advanced gastric cancer. Although palliative radiotherapy (RT) is effective for several symptoms in gastric cancer, the duration of efficacy is limited. We report a case where palliative RT significantly improved malignant cardiac obstruction caused by gastric cancer over a long period of time.

A 78-year-old woman was referred to our hospital for anorexia and severe anemia. Esophagogastroduodenoscopy showed the giant gastric tumor in cardia and it was thought to be the cause of anemia. Biopsy revealed poorly differentiated adenocarcinoma; she was diagnosed with gastric cancer. Her clinical cancer staging was IV and she wished to receive palliative care. The malignant cardiac obstruction became severe, and to improve the obstruction, palliative RT was performed. The gastric tumor with a diameter of 4 cm was significantly reduced and the obstruction disappeared. For three years after RT, she had no obstruction symptom.

The sensitivity of cells to radiation is proportional to the degree of differentiation. Palliative RT is effective for several symptoms in gastric cancer, and in our case, the duration of RT efficacy was long. Hence, RT may be useful when the histological type is poorly differentiated in gastric cancer.

Synergistic anticancer effects of everolimus (RAD001) and Rhein on gastric cancer cells via phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway

Everolimus (RAD001) is a mTOR inhibitor and is widely used for the treatment of gastric cancer (GC). Evidence suggests that Rhein has anticancer effect on GC. But the synergistic effect and mechanism of RAD001 and Rhein combination on GC is not clear. The current study aims to clarify the combination of RAD001 and Rhein in GC treatment. We found Rhein dose-dependently repressed MGC-803 cell viability (50% inhibition concentration (IC50) value = 94.26 μM). Rhein (80 μM) significantly suppressed GC cell proliferation and invasion. RAD001 dose-dependently repressed MGC-803 cells viability (IC50 value = 45.41 nM). The combination of Rhein and RAD001 repressed MGC-803 cells viability, invasion, and proliferation compared to the administration of Rhein or RAD001 alone. Protein levels of epithelial-mesenchymal transition (EMT)-related molecules E-cadherin, N-cadherin and Vimentin expressions were significantly affected by the combination of Rhein and RAD001. The combination of Rhein and RAD001 significantly facilitated cell apoptosis and up-regulated expressions of cell apoptosis and cycle-related protein p53, cyclin-dependent kinase 4 (CDK4) and cyclin D1 compared to the administration of Rhein or RAD001 alone. Moreover, the combination of Rhein and RAD001 repressed the expressions of phosphorylation-phosphoinositide-3-kinase (p-PI3K), p-protein kinase B (p-AKT) and p-mammalian target of rapamycin (p-mTOR). Finally, the combination of RAD001 and Rhein significantly decreased tumor weight and volume, suppressed the expressions of p-PI3K, p-Akt and p-mTOR, and repressed cell proliferation marker Ki-67 expression, which exerted synergistic cancer prevention in GC in vivo. Overall, the combination of Rhein and RAD001 exert synergistic cancer prevention in GC via PI3K/Akt/mTOR pathway.

MicroRNA-223-3p is involved in fracture healing by regulating fibroblast growth factor receptor 2

MicroRNAs (miRNAs) are powerful modulators of fracture healing. The research explored the level of serum miR-223-3p in fracture patients and its potential mechanism in fracture healing. In the study, miR-223-3p levels in 42 patients with intra-articular fracture and 40 patients with hand fracture were detected by real-time fluorescence quantitative PCR reaction (qRT-PCR). Subsequently, osteoblasts MC3T3-E1 was transfected with miR-223-3p mimic or inhibitor, and cell function was detected by Cell counting kit (CCK-8) assay and flow cytometry. Dual-luciferase reporter assay verified the regulation mechanism of miR-223-3p and its target genes. We found that miR-223-3p was significantly elevated over time in patients with intra-articular fracture and hand fracture compared with healthy individuals. Moreover, increased miR-223-3p significantly reduced cell viability and promoted cell apoptosis. The fibroblast growth factor receptor 2 (FGFR2) was the target of miR-223-3p. Serum FGFR2 was significantly decreased in patients, which was contrary to the expression of miR-223-3p. Moreover, FGFR2 levels in cells were negatively regulated by miR-223-3p. Finally, si-FGFR2 significantly reversed the promotion of miR-223-3p inhibitor on cell viability and the inhibition of cell apoptosis. Our research suggested that miR-223-3p is highly expressed in fracture patients, and regulates osteoblast cell viability and apoptosis by targeting FGFR2. This may be a valuable target for fracture healing therapy and provide a new perspective for its treatment.