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The present study is aimed to investigate the regulatory effects and related mechanism of long non-coding RNA testis-specific transcript, Y-linked 15 (TTTY15) in gastric carcinoma (GC) cell proliferation, migration, invasion, apoptosis and epithelial-mesenchymal transition (EMT). TTTY15 expression in GC tissue samples and cells was detected by quantitative real-time PCR (qRT-PCR), and the correlation between TTTY15 expression and GC clinicopathological indicators was analyzed. Cell counting kit-8 (CCK-8), BrdU, flow cytometry and Transwell assays were performed for detecting GC cell proliferation, migration, invasion and apoptosis. Western blot was performed for detecting the expressions of EMT-associated proteins (N-cadherin and E-cadherin), Wnt family member 1 (Wnt1) protein and β-catenin protein. Bioinformatics analysis was conducted to predict, and RNA immunoprecipitation (RIP) assay and dual-luciferase reporter gene assay were performed to verify the targeted relationships of microRNA let-7a-5p (let-7a-5p) with TTTY15 and Wnt1 mRNA 3'UTR. It was found that TTTY15 expression was significantly up-regulated in GC tissues and cells, and was associated with advanced TNM stage and poor tumor differentiation. TTTY15 overexpression promoted GC cell proliferation, migration and invasion, the expressions of N-cadherin, Wnt1 and β-catenin protein, and inhibited the apoptosis and E-cadherin expression, while knocking down TTTY15 had the opposite effects. TTTY15 directly targeted let-7a-5p and negatively regulated its expression. Wnt1 was the target gene of let-7a-5p, and TTTY15 could indirectly and positively regulate Wnt1 expression. In conclusion, TTTY15 promotes GC progression, by regulating the let-7a-5p/Wnt1 axis to activate the Wnt/β-catenin pathway.

The invasion of osteoclasts into the cartilage via blood vessels advances the process of endochondral ossification, and dysregulation of dynamic intercellular interactions results in skeletal dysplasias. Although the regulation of osteoclasts by growth plate chondrocytes has been reported in detail, the effect of osteoclasts on chondrocytes remains to be determined. In this study, ATDC5 cells and bone marrow mesenchymal stem cells were differentiated into chondrocytes and treated with conditioned medium obtained from bone marrow macrophages differentiated to osteoclast precursors and osteoclasts. Exosomes were inhibited in conditioned medium or isolated directly from osteoclasts to further determine whether osteoclast-derived exosomes play an important role in chondrocyte hypertrophy. Additionally, exosomal miRNAs were detected, and let-7a-5p was selected as an miRNA with significantly increased expression in osteoclast-derived exosomes. Experiments were performed to verify the potential target Smad2 and investigate how let-7a-5p affected chondrocytes. The results suggest that both osteoclast precursors and osteoclasts promote chondrocyte hypertrophy and that the promotive effect of osteoclasts is more significant than that of osteoclast precursors. Osteoclast-derived exosomes promote the hypertrophic differentiation of chondrocytes. Moreover, osteoclast-derived exosomal let-7a-5p inhibits Smad2 to decrease the transforming growth factor-β-induced inhibition of chondrocyte hypertrophy. Our research reveals the role of osteoclasts in the regulation of chondrocytes and provides insights into the highly coordinated intercellular process of endochondral ossification.

Autophagy is essential for cellular metabolism and plays pivotal roles in carcinogenesis, while excessive autophagy induces toxicity and cell death. Our previous studies have suggested that let-7a-5p/BCL-xL might regulate autophagy in lung cancer, but the regulatory mechanism is unclear. The central goal of the study was to figure out the role of let-7a-5p/BCL-xL in the initiation of autophagy and its effect on the migration, invasion, and proliferation of A549 cells as well as its therapeutic potential in lung cancer. Based on the genome-wide expression profiles of lung cancer, BCL-xL and let-7a-5p were found to be dysregulated and negatively correlated in lung adenocarcinoma, which was associated with the survival of lung cancer. The crosstalk between BCL-xL and let-7a-5p was then investigated using dual-luciferase reporter assay, and it was found to suppress the migration and invasion of A549 cells. Further, we found that the crosstalk between BCL-xL and let-7a-5p could lead to toxic autophagy and cell death through activating the PI3K-signaling pathway, which was independent of apoptosis or pyroptosis. These findings indicate that let-7a-5p is a sensitive initiator for toxic autophagy in A549 lung cancer cells and is an appealing target for lung cancer therapy., (© 2019 The Author(s).)

Background: This study aimed to explore the correlation of circulating microRNA (miRNA) expression profile with clinical response to tumor necrosis factor (TNF) inhibitor in treating rheumatoid arthritis (RA) patients., Methods: Baseline PBMC samples from eight responders and eight non-responders after 24-week TNF inhibitor (etanercept) treatment were subjected to miRNA microarray. Then, top 10 dysregulated miRNAs were selected and further validated by quantitative polymerase chain reaction (qPCR) in baseline PBMC samples from 92 RA patients treated with 24-week TNF inhibitor (etanercept). Responders and non-responders were divided referring to the decline in disease activity score in 28 joints., Results: In microarray assay, total 59 upregulated and 78 downregulated miRNAs were identified in responders compared to non-responders, which were mainly enriched in regulating immune- and inflammation-related biological processes and pathways. The top 10 dysregulated miRNAs were as follows: miR-192-5p, miR-146a-5p, miR-19b-3p, miR-320c, miR-335-5p, miR-149-3p, miR-766-3p, let-7a-5p, miR-24-3p, and miR-1226-5p. In qPCR validation, miR-146a-5p was increased, while let-7a-5p was decreased in responders compared with non-responders. Multivariate logistic analysis illuminated that miR-146a-5p and CRP independently correlated with higher clinical response, while let-7a-5p and biologics history independently associated with lower clinical response. Subsequently, receiver operating characteristic curve showed that combination of these four independent factors presented with a great predictive value for clinical response with area under curve: 0.863, 95% CI 0.781-0.945., Conclusion: miRNA expression profile is closely implicated in the treatment efficacy of TNF inhibitor, and combined measurement of miR-146a-5p, let-7a-5p, CRP, and biologics history disclosed a great predictive value for clinical response to TNF inhibitor in RA patients., (© 2019 The Authors. Journal of Clinical Laboratory Analysis Published by Wiley Periodicals, Inc.)

Objective: To investigate the clinical significance of serum let-7a-5p and miR-21-5p in the diagnosis of breast cancer., Methods: We examined 32 healthy people and 30 patients with benign breast lesions as controls and 90 breast cancer patients as study subjects. The expression of let-7a-5p and miR-21-5p were detected in all subjects' samples, and Cel-miR-39-3p was used as a spike-in reference. Serum miRNAs were extracted by the TRIzol method, and reverse transcription was performed with specific primers for let-7a-5p, miR-21-5p and Cel-miR-39-3p, and 2-μL reverse transcription products were used as PCR templates. A SLAN-96P fluorescent quantitative PCR instrument was used for quantitative PCR detection., Results: (1) The serum levels of carcinoembryonic antigen (CEA)and carbohydrate antigen 15-3 (CA15-3) in the breast cancer group were higher than those in the healthy controls and patients with benign breast lesions; (2) The expression level of let-7a-5p in the serum of the breast cancer group was lower than that in the healthy control group ( P <0.05), but there was no significant difference compared to the breast benign lesion group ( P >0.05); (3) The serum expression level of miR-21-5p in the breast cancer group was lower than that in the healthy control group ( P <0.05) but was not significantly different from that in the patients with benign breast lesions ( P >0.05)., Conclusion: Reduced expression of Let-7a-5p and miR-21-5p levels is of little value for early diagnosis of breast cancer; however reduced expression of Let-7a-5p and miRNA-21-5p may serve as non-invasive biomarkers for the diagnosis of breast cancer metastasis, and combination of these markers with CEA and CA15-3 can help to distinguish benign breast lesions from breast cancer., (© 2019 by the Association of Clinical Scientists, Inc.)

Tumor cells metabolize more glucose to lactate in aerobic or hypoxic conditions than normal cells. Pyruvate kinase isoenzyme type M2 (PKM2) is crucial for tumor cell aerobic glycolysis. We established a role for let-7a-5p/Stat3/hnRNP-A1/PKM2 signaling in breast cancer cell glucose metabolism. PKM2 depletion via small interfering RNA (siRNA) inhibits cell proliferation and aerobic glycolysis in breast cancer cells. Signal transducer and activator of transcription 3 (Stat3) promotes upregulation of heterogeneous nuclear ribonucleoprotein (hnRNP)-A1 expression, hnRNP-A1 binding to pyruvate kinase isoenzyme (PKM) pre messenger RNA, and the subsequent formation of PKM2. This pathway is downregulated by the microRNA let-7a-5p, which functionally targets Stat3, whereas hnRNP-A1 blocks the biogenesis of let-7a-5p to counteract its ability to downregulate the Stat3/hnRNP-A1/PKM2 signaling pathway. The downregulation of Stat3/hnRNP-A1/PKM2 by let-7a-5p is verified using a breast cancer. These results suggest that let-7a-5p, Stat3, and hnRNP-A1 form a feedback loop, thereby regulating PKM2 expression to modulate glucose metabolism of breast cancer cells. These findings elucidate a new pathway mediating aerobic glycolysis in breast cancers and provide an attractive potential target for breast cancer therapeutic intervention., (© 2018 Wiley Periodicals, Inc.)

Background: The liver is a vital target for sepsis-related injury, leading to inflammatory pathogenesis, multiple organ dysfunction and high mortality rates. Monocyte-derived macrophage transformations are key events in hepatic inflammation. N 1 -[(4-methoxy)methyl]-4-methyl-1,2-benzenediamine (FC-99) previously displayed therapeutic potential on experimental sepsis. However, the underlying mechanism of this protective effect is still not clear., Results: FC-99 treatment attenuated the liver dysfunction in septic mice that was accompanied with reduced numbers of pro-inflammatory Ly6C hi monocytes in the peripheral blood and CD11b + F4/80 lo monocyte-derived macrophages in the liver. These effects were attributed to the FC-99-induced apoptosis of CD11b + cells. In PMA-differentiated THP-1 cells, FC-99 repressed the expression of CD11b, CD14 and caspase3 and resulted in a high proportion of Annexin V + cells. Moreover, let-7a-5p expression was abrogated upon CLP stimulation in vivo , whereas it was restored by FC-99 treatment. TargetScan analysis and luciferase assays indicated that the anti-apoptotic protein BCL-XL was targeted by let-7a-5p. BCL-XL was inhibited by FC-99 in order to induce monocyte apoptosis, leading to the impaired monocyte-to-macrophage differentiation., Materials and Methods: Murine acute liver failure was generated by caecal ligation puncture surgery after FC-99 administration; Blood samples and liver tissues were collected to determine the monocyte/macrophage subsets and the induction of apoptosis. Human acute monocytic leukemia cell line (THP-1) cells were pretreated with FC-99 followed by phorbol-12-myristate-13-acetate (PMA) stimulation, in order to induce monocyte-to-macrophage differentiation. The target of FC-99 and the mechanistic analyses were conducted by microarrays, qRT-PCR validation, TargetScan algorithms and a luciferase report assay., Conclusions: FC-99 exhibits potential therapeutic effects on CLP-induced liver dysfunction by restoring let-7a-5p levels., Competing Interests: CONFLICTS OF INTEREST The authors declare that there is no conflicts of interest.

Colorectal cancer (CRC) guidelines recommend adjuvant chemotherapy according to the level of lymph node metastasis. Let-7a-5p is a microRNA, which inhibits migration, invasion, as well as the epithelial-mesenchymal transition by targeting HMGA2. The aim of this study was to investigate the role of let-7a-5p in the clinical impact of CRC. In this study, one hundred and ninety-two CRC patients were enrolled. The expression of let-7a-5p and HMGA2 in serum and tumour tissues were analysed by real-time PCR and immunohistochemistry. Kaplan-Meier analysis was used to analyse primary outcomes, including the survival and tumour recurrence. The expression of let-7a-5p in tumour tissues was significantly negative correlated with the tumour size, stage and lymph node metastasis in CRC patients (p = 0.024 for tumour size, p < 0.0001 for stage and p < 0.0001 for lymph node metastasis). There was a negative correlation between the levels of let-7a-5p and the HMGA2 protein (p < 0.0001). The overall survival (OS) and disease-free survival (DFS) rates of patients with let-7a-5p low/HMGA2 high were poorer than those with let-7a-5p high/HMGA2 high, let-7a-5p high/HMGA2 low and let-7a-5p low/HMGA2 low. In addition, the expression levels of let-7a-5p in serums were positively correlated with let-7a-5p in the tumour tissues of the CRC patients. The expression levels of let-7a-5p in serums also could be used as a biomarker to predict clinical outcome. We suggest that down-regulation of let-7a-5p in serums and tumour tissues of CRC patients could be used to predict lymph node metastasis and the disease prognosis. These results could be implicated for chemotherapy suggestion., (Copyright © 2016 Elsevier Ltd. All rights reserved.)