Background: Exosomes, widely recognized natural nanovesicles, represent one of the recently discovered modes of intercellular communication due to their ability to transmit crucial cellular information that can be engineered to have robust delivery and targeting capacity. MiR-142-3p, one of the upregulated microRNAs (miRNAs) in many types of breast cancer, activates the canonical Wnt signaling pathway and transactivates the miR-150 expression, and results in the hyperproliferation of cancer cells in vitro and mammary glands in vivo. Materials and methods: In this study, we exploited the exosomes isolated from bone marrow-derived mesenchymal stem cells (MSCs-Exo) to deliver LNA (locked nucleic acid)-modified anti-miR-142-3p oligonucleotides to suppress the expression level of miR-142-3p and miR-150 in 4T1 and TUBO breast cancer cell lines. Results: The in vitro results showed that the MSCs-Exo can efficiently deliver anti-miR-142-3p to reduce the miR-142-3p and miR-150 levels and increase the transcription of the regulatory target genes, APC and P2X7R. We also evaluated in vivo distribution of the MSCs-Exo in tumor-bearing mice. The in vivo result indicated that MSCs-Exo can penetrate the tumor site and are suitable nanovehicles to deliver the inhibitory oligonucleotides into the tumor tissues to downregulate the expression levels of miR-142-3p and miR-150. Conclusion: We showed that MSCs-derived exosomes could be used as a feasible nanovehicle to deliver drug molecules like LNA-anti-miR-142-3p in both in vitro and in vivo studies.

Hepatocellular carcinoma (HCC) is one of the most common types of malignancies worldwide. There is little information on the mechanisms involved in the pathogenesis of this disease. Diagnosis of HCC at early stages would be crucial for increasing the survival of patients. Circulating miRNAs have emerged as one of the most attractive tools for an early diagnosis of cancers. Various studies have shown that there is an aberrant expression of miRNAs such as miR-25, miR-375, miR-206, miR-223, miR- 92a, miR-222, miR-1, let-7f and miR-21 in HCC. Circulating and tissue miRNAs have also key roles in the pathogenesis of HCC by affecting several biologically important pathways such as p53, p21, PTEN, PI3K-AKT, c-Myc and STAT3. In this review, we summarize the current knowledge on the role of miRNAs in diagnosis, prognosis, and treatment of HCC.