The Wnt1 protein, a secreted ligand that activates Wnt signaling pathways, contributes to the self-renewal of cancer stem cells (CSCs) and thus may be a major determinant of tumor progression and chemoresistance. In a series of gastric cancer specimens, we found strong correlations among Wnt1 expression, CD44 expression, and the grade of gastric cancer. Stable overexpression of Wnt1 increased AGS gastric cancer cells' proliferation rate and spheroids formation, which expressed CSC surface markers Oct4 and CD44. Subcutaneous injection of nude mice with Wnt1-overexpressing AGS cells resulted in larger tumors than injection of control AGS cells. Salinomycin, an antitumor agent, significantly reduced the volume of tumor caused by Wnt1-overexpressing AGS cells in vivo. This is achieved by inhibiting the proliferation of CD44+Oct4+ CSC subpopulation, at least partly through the suppression of Wnt1 and β-catenin expression. Taken together, activation of Wnt1 signaling accelerates the proliferation of gastric CSCs, whereas salinomycin acts to inhibit gastric tumor growth by suppressing Wnt signaling in CSCs. These results suggest that Wnt signaling might have a critical role in the self-renewal of gastric CSCs, and salinomycin targeting Wnt signaling may have important clinical applications in gastric cancer therapy.

MicroRNAs (miRNAs) have been proven to be involved in cell metastasis and angiogenesis by interaction with the target mRNAs. Evidence has been confirmed that miR-140-5p is a tumor suppressor in human cancers such as breast cancer. However, the potential molecular mechanism of miR-140-5p in breast cancer invasion and angiogenesis is still poorly understood. According to our study, we reported that miR-140-5p inhibited the tumor invasion and angiogenesis of breast cancer cells both in vitro and in vivo by targeting VEGF-A. The mRNA amount of miR-140-5p was decreased in the breast cancer clinical samples and breast cancer with metastasis compared with the corresponding adjacent normal tissues and cancer without metastasis. MiR-140-5p mimics and a negative control were transfected into human MCF-7 and MDA-MB-231 cells. Transwell chambers were used to detect the invasive ability of the cells, and the angiogenic ability was assessed by tube-formation assay. The markers of invasion and angiogenesis, VEGF-A, CD31 and MMP-9, were detected by using immunohistochemistry and western blot analysis in vivo. VEGF-A was verified as a possible target gene of miR-140-5p, and corroborated by dual-luciferase reporter and ELISA. Taken together, the study elucidates the molecular mechanisms by which miR-140-5p inhibits breast cancer metastasis and angiogenesis, and provides a potent evidence for the development of a novel microRNA-targeting anticancer strategy for breast cancer patients.

MicroRNAs (miRNAs) are a class of small noncoding RNAs that are approximately 22 nt in length and regulate gene expression post-transcriptionally. miRNAs play a vital role in both physiological and pathological processes and are regarded as promising biomarkers for cancer, cardiovascular diseases, neurodegenerative diseases, and so on. Accurate detection of miRNA expression level in clinical samples is important for miRNA-guided diagnostics. However, the common miRNA detection approaches like RNA sequencing, qRT-PCR, and miRNA microarray are performed in a professional laboratory with complex intermediate steps and are time-consuming and costly, challenging the miRNA-guided diagnostics. Hence, sensitive, highly specific, rapid, and easy-to-use detection of miRNAs is crucial for clinical diagnosis based on miRNAs. With the advantages of being specific, sensitive, efficient, cost-saving, and easy to operate, point-of-care testing (POCT) has been widely used in the detection of miRNAs. For the first time, we mainly focus on summarizing the research progress in POCT of miRNAs based on portable instruments and visual readout methods. As widely available pocket-size portable instruments and visual detection play important roles in POCT, we provide an all-sided discussion of the principles of these methods and their main limitations and challenges, in order to provide a guide for the development of more accurate, specific, and sensitive POCT methods for miRNA detection.

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