Micro-325 inhibiting malignant biological characteristics of glioma cells via transferrin receptor pathway

Abstract

Objective To study the influence of micro (miR)-325 in progression of glioma and its molecular mechanism by regulating transferrin receptor (TFRC) gene expression in glioma cells. Methods (1) Thirty-five glioma tissues and paired adjacent normal tissues were collected during surgical excision performed in our hospital from January 2015 to January 2018. The miR-325 and TFRC mRNA expression levels in the glioma tissues and paired adjacent normal tissues were detected by inverse transcription-quantitative PCR (RT-qPCR); the expression of miR-325 in glioma tissues of patients with different clinical characteristics and the survival curves of patients with low or high miR-325 expressions were compared. (2) RT-qPCR was used to examine the miR-325 expression in HA, U251, and U87 cell lines in vitro; the regulatory relations between miR-325 and its potential target gene TFRC in U251, and U87 cell lines were measured by luciferase report assay; miR-325 mimic and its negative control were transfected into U251 and U87 cell lines for 48 h, and then, the mRNA and protein expressions of TFRC were detected by RT-qPCR and Western blotting, respectively; control small interfering RNA (siRNA)+nonsense inhibitor, TFRC siRNA+nonsense inhibitor, and siTFRC+miR-325 inhibitor were transfected into U251 and U87 cell lines for 48 h, respectively, Western blotting was employed to detect the TFRC protein expression, cell proliferation was detected by CCK-8 assay, and cell invasion was detected by Transwell assay; pcDNA3.1 empty vector+nonsense sequence, TFRC pcDNA3.1+nonsense sequence, TFRC pcDNA3.1+miR-325 mimic were transfected into U251 and U87 cell lines for 48 h, respectively, TFRC protein expression was detected by Western blotting, cell proliferation was detected by CCK-8 assay, and cell invasion was detected by Transwell assay. Results (1) As compared with those in the adjacent tissues, the miR-325 expression was significantly decreased and the TFRC mRNA expression was statistically increased in glioma tissues (P<0.05); the TFRC mRNA expression and miR-325 expression were negatively correlated in glioma tissues (P<0.05); as compared with patients with Karnofsky functional status scores≥80, patients with scores<80 had significantly decreased miR-325 expression; as compared with glioma tissues of WHO grading I-II, glioma tissues of grading III-IV had significantly decreased miR-325 expression (P<0.05); the survival rate of patients with low miR-325 expression was statistically lower than that of patients with high miR-325 expression (P< 0.05). (2) As compared with that in HA cells, the miR-325 expression was statistically down-regulated in U87 and U251 cells (P<0.05); in TFRC wild-type (TFRC WT) transfected cells, the miR-325 mimic group had significantly lower luciferase activity than the nonsense sequence group, while the miR-325 inhibitor group had significantly higher luciferase activity than the nonsense inhibitor group (P<0.05); as compared with those in the nonsense sequence group, the TFRC mRNA and protein expressions were statistically decreased in U87 and U251 cells of miR-325 mimic group; as compared with those in the control siRNA+nonsense inhibitor group, the TFRC protein expression and absorbance value were significantly decreased, and number of invasive cells was significantly smaller in the siTFRC+nonsense inhibitor group; and as compared with those in the siTFRC+nonsense inhibitor group, the TFRC protein expression and absorbance value were significantly increased, and number of invasive cells was significantly larger in the siTFRC+miR-325 inhibitor group (P<0.05); as compared with the pcDNA3.1 empty vector+nonsense sequence group, the TFRC protein expression and absorbance value were significantly increased, and number of invasive cells was significantly larger in the TFRC pcDNA3.1+nonsense sequence group, and as compared with the TFRC pcDNA3.1+nonsense sequence group, the TFRC protein expression and absorbance value were significantly decreased, and number of invasive cells was significantly smaller in the TFRC pcDNA3.1+miR-325 mimic group (P<0.05). Conclusion The miR-325 expression is decreased in glioma cells and has a tumor suppressor effect; patients with low miR-325 expression have poor prognosis; miR-325 inhibits cancer cell progression by inhibiting the expression of the target gene TFRC. Key words: Micro-325; Transferrin receptor; Glioma; U87 cell; U251 cell