J Korean Med Sci.  2016 May;31(5):688-694. 10.3346/jkms.2016.31.5.688.

Silencing of Long Non-Coding RNA MALAT1 Promotes Apoptosis of Glioma Cells

• Xiang J
• Guo S
• Jiang S
• Xu Y
• Li J
• Li L
• Xiang J

• KMID: 2373664
• DOI: http://doi.org/10.3346/jkms.2016.31.5.688

Abstract

The metastasis-associated lung adenocarcinoma transcription 1 (MALAT1) is a highly conserved long non-coding RNA (lncRNA) gene. However, little is known about the pathological role of lncRNA MALAT1 in glioma. In the present study, we explored the expression level of lncRNA MALAT1 in primary glioma tissues as well as in U87 and U251 glioma cell lines. Using qRT-PCR, we found that the expression of lncRNA MALAT1 was significantly increased in glioma tissues compared with that of paracancerous tissues. Meanwhile, the expression of MALAT1 was highly expressed in U98 and U251 cells. In order to explore the function of MALAT1, the expression of MALAT1 was greatly reduced in U87 and U251 cells transfected with siRNA specifically targeting MALAT1. Consequently, cell viability of U87 and U251 cells were drastically decreased after the knockdown of MALAT1. Concomitantly, the apoptosis rate of the two cell lines was dramatically increased. Furthermore, the expression levels of some tumor markers were reduced after the knockdown of MALAT1, such as CCND1 and MYC. In summary, the current study indicated a promoting role of MALAT1 in the development of glioma cell.

Keyword

RNA, Long Noncoding; MALAT1 Long Non-coding RNA, Human; Glioma; Apoptosis

MeSH Terms

*Apoptosis
Biomarkers, Tumor/genetics/metabolism
Blotting, Western
Cell Line, Tumor
Cell Movement
Cell Proliferation
Cyclin D1/genetics/metabolism
Down-Regulation
Flow Cytometry
Glioma/metabolism/pathology
Humans
Proto-Oncogene Proteins c-myc/genetics/metabolism
*RNA Interference
RNA, Long Noncoding/antagonists & inhibitors/genetics/*metabolism
RNA, Small Interfering/metabolism
Real-Time Polymerase Chain Reaction
Biomarkers, Tumor
Cyclin D1
Proto-Oncogene Proteins c-myc
RNA, Long Noncoding
RNA, Small Interfering

Figure

• 

  Fig. 1 MALAT1 was highly expressed in glioma patients and cell lines. (A) 37 glioma tissue samples and adjacent normal brain samples were selected, and then qRT-PCR assay was employed to detect the relative expression level of MALAT1 in glioma patients. The adjacent normal brain tissues (paracancer group) were used as the negative control. (B) Human malignant glioma cell lines U87 and U251 cells were cultured, and then qRT-PCR assay was employed to detect the relative expression level of MALAT1 in both cells. The normal glia cell line NHA was used as the negative control. (C) U87 and U251 cells were transfected with siRNA targeting MALAT1, QRT-PCR assay was employed to detect the endogenous expression of MALAT1 to confirm the knockdown efficiency. The glioma cells transfected with Scramble was used as the negative control. *P < 0.05 vs. the control; † P < 0.01 vs. the control.

• 

  Fig. 2 Knockdown of MALAT1 decreased the growth of glioma cells. (A, B) U87 and U251 cells were seeded into 96-well plates and cultured for 0 hours, 24 hours, 48 hours, 72 hours and 96 hours respectively, MTT assay was employed to detect the effect of MALAT1 knockdown on cell growth at different time points in both cells. The glioma cells transfected with Scramble was used as the negative control. *P < 0.05 vs. the control. (C, D) U87 and U251 cells in serum-free medium were placed into the upper transwell chamber, the invasion assays in vitro were carried out to detect the effect of MALAT1 knockdown on cell invasion after 24 hours of incubation. The glioma cells transfected with Scramble was used as the negative control. *P < 0.05 vs. the control.

• 

  Fig. 3 Knockdown of MALAT1 increased the apoptosis rate of glioma cells. (A, B) U87 and U251 cells were seeded in 6 well plates and grow to a confluency of 70%, then both cells were transfected with si-MALAT1 or Scramble respectively. Annexin V-FITC/PI double staining assay was employed to detect the effect of MALAT1 knockdown on the apoptosis rate in U87 (A) and U251 (B) cells. The glioma cells transfected with Scramble was used as the negative control. FL2-H, FL2-Height.

• 

  Fig. 4 CCND1 and MYC was down-regulated with MALAT1 knockdown. U87 and U251 cells were seeded in 60 mm plates and grow to a confluency of 70%, then both cells were transfected with si-MALAT1 or Scramble respectively. QRT-PCR and western blot analysis were employed to verify the change of expression levels of CCND1 and MYC in response to MALAT1 knockdown in U87 cells (A, B) and U251 cells (C, D). The cells transfected with Scramble was used as the negative control. *P < 0.05 vs. the control; † P < 0.01 vs. the control.

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