Overexpression of microRNA-21 strengthens stem cell-like characteristics in a hepatocellular carcinoma cell line

Abstract

BackgroundLiver cancer stem cells (LCSCs) have been shown to express higher levels of microRNA-21 (miR-21). Here, we examine the possible contributions of miR-21 to the phenotype of LCSCs in culture and in xenograft tumors in nude mice.MethodsThe hepatocellular carcinoma cell line MHCC-97H was stably transformed with a retroviral vector to establish cells overexpressing miR-21, while a cell line transformed with empty vector served as a negative control. RT-PCR and Western blotting were used to evaluate the effects of miR-21 overexpression on the expression of various LCSC markers, a Transwell assay was used to assess the effects on cell migration and invasion, and a spheroid formation assay was used to examine the effects on clonogenesis. The effects of miR-21 overexpression were also examined in tumors in nude mice.ResultsAn MHCC-97H cell line was constructed that stably overexpresses miR-21 at 7.78 ± 1.51-fold higher levels than the negative control cell line. Expression of the LCSC markers CD13, Ep-CAM, CD90, and OCT4 was significantly higher in the miR-21-overexpressing cell line than in the negative control at both mRNA and protein levels. The overexpressing cell line formed larger, tighter, and more numerous spheroids. Overexpression of miR-21 was associated with greater cell migration and invasion. Tumors of overexpressing cells in nude mice had a significantly larger mean volume after 34 days of growth (773.62 ± 163.46 mm3) than tumors of negative control cells (502.79 ± 33.94 mm3, p = 0.048), as well as greater mean weight (0.422 ± 0.019 vs. 0.346 ± 0.006 g, p = 0.003).ConclusionsOverexpression of miR-21 strengthens the phenotype of LCSCs, facilitating invasion, migration, and tumorigenesis in hepatocellular carcinoma.

The functional mechanism of miR-125b in gastric cancer and its effect on the chemosensitivity of cisplatin

“…Importantly, abnormal expression caused by miRNA regulation could lead to the pathogenesis and development of various tumors [ 9 ]. For example, numerous studies indicate that miR-21 is implicated in colorectal cancer [ 10 ], hepatocellular carcinoma [ 11 ], gastric cancer [ 12 ] and other cancers. Another miRNA, miR-125b, has also been shown to exert abnormal expression in a variety of tumors and its effects vary with different tumors [ 13 , 14 ].…”

Circulating Exosomal MicroRNA-21 as a Biomarker in Each Tumor Stage of Colorectal Cancer

“…It is known that overexpressed miR-21 downregulates the expression of PTEN, PDCD4, and TPM1, promoting cell proliferation and cancer progression [34]. Furthermore, overexpression of miR-21 strengthens the phenotype of cancer stem cells, facilitating invasion, migration, and tumorigenesis in hepatocellular carcinoma [35]. It has been reported that tumor-derived exosomes containing miRNAs can initiate premetastatic niche formation by causing host cells to promote metastasis [36].…”

A meta-analysis on the prognosis of exosomal miRNAs in all solid tumor patients

“…[34] In addition, overexpressed miR-21 enhances the phenotype of cancer stem cells and promotes the invasion, migration, and tumorigenesis in hepatocellular carcinoma. [35] MiR-451a plays a crucial role in the development of human cancers. Kim et al [36] found that miR-451a regulated gliomatous cell proliferation and migration by means of the LKB1-AMPK signaling pathway.…”