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LIN28B is highly expressed in atypical teratoid/rhabdoid tumor (AT/RT) and suppressed through the restoration of SMARCB1.

Choi SA, Kim SK, Lee JY, Wang KC, Lee C, Phi JH - Cancer Cell Int. (2016)

Bottom Line: The knockdown of LIN28B decreased cell viability and proliferation, induced cell cycle arrest, and reduced migration in primary cultured AT/RT cells.The restoration of SMARCB1 in AT/RT cells decreased the expression of LIN28B and CCND1.These results show that LIN28B might be regulated through SMARCB1; the loss of SMARCB1 protein in AT/RT results in the unopposed expression of LIN28B and related oncogenes such as CCND1, leading to tumorigenesis.

View Article: PubMed Central - PubMed

Affiliation: Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, 101 Daehakro, Jongno-gu, Seoul, 03080 Republic of Korea.

ABSTRACT

Background: Atypical teratoid/rhabdoid tumor (AT/RT) is a highly malignant brain tumor that almost exclusively develops in young children. AT/RT belongs to the embryonal brain tumor group, comprising primitive tumors recapitulating the early development of the central nervous system during embryogenesis. The loss of SMARCB1 protein expression is a hallmark of AT/RT pathogenesis. LIN28A/B is a key gene in embryonic development and for the maintenance of pluripotency in stem cells. LIN28B might be an important co-player in AT/RT pathogenesis, considering the primitive nature and young age onset of AT/RT.

Methods: We explored the expression patterns of LIN28B in AT/RT and compared it with the expression in cortical dysplasia and medulloblastoma. The functional role of LIN28B was assessed using LIN28B-siRNAs in primary cultured AT/RT cells.

Results: LIN28B is highly expressed in AT/RT compared with medulloblastoma and other embryonal tumors, whereas primary let-7g miRNA is down-regulated. AT/RT also showed higher expression of CCND1 and MYC, and lower expression of CDKN1C. The suppression of CCND1 expression and enhanced expression of CDKN1C were also observed. The knockdown of LIN28B decreased cell viability and proliferation, induced cell cycle arrest, and reduced migration in primary cultured AT/RT cells. Furthermore, we showed that the knockdown of LIN28B decreased the expression of other pluripotency-related genes (OCT4 and NANOG) and the mesenchymal-epithelial transition signature. We also transfected wild-type SMARCB1 into primary cultured AT/RT cells. The restoration of SMARCB1 in AT/RT cells decreased the expression of LIN28B and CCND1.

Conclusions: These results show that LIN28B might be regulated through SMARCB1; the loss of SMARCB1 protein in AT/RT results in the unopposed expression of LIN28B and related oncogenes such as CCND1, leading to tumorigenesis. Therefore, the strategic role of LIN28B in AT/RT might be utilized as an important therapeutic target.

No MeSH data available.


Related in: MedlinePlus

Effect of LIN28B knockdown on AT/RT cells. The level of LIN28B mRNA and protein was effectively inhibited after the transfection of LIN28B-siRNAs. a RT-qPCR and b western blot analysis showed that LIN28B knockdown reduced CCND1 expression and enhanced CDKN1C expression. c The increased expression of pre-leg-7g and mature let-7g miRNA was observed after LIN28B knockdown. *P < 0.05; **P < 0.01; ***P < 0.01. Error bars represent ±SD
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Fig3: Effect of LIN28B knockdown on AT/RT cells. The level of LIN28B mRNA and protein was effectively inhibited after the transfection of LIN28B-siRNAs. a RT-qPCR and b western blot analysis showed that LIN28B knockdown reduced CCND1 expression and enhanced CDKN1C expression. c The increased expression of pre-leg-7g and mature let-7g miRNA was observed after LIN28B knockdown. *P < 0.05; **P < 0.01; ***P < 0.01. Error bars represent ±SD

Mentions: To determine the role of LIN28B in AT/RT, we performed siRNA knockdown experiments using two distinct siRNA constructs (LIN28B siRNA-1 and LIN28B siRNA-2). The knockdown efficiency was confirmed using RT-qPCR and western blot analysis in two primary cultured AT/RT cell lines (SNU-AT/RT3 and SNU-AT/RT4). The LIN28B siRNAs effectively degraded LIN28B (LIN28B siRNA-1 in SNU-AT/RT3, p = 0.009; LIN28B siRNA-1 in SNU-AT/RT4, p = 0.002; LIN28B siRNA-2 in SNU-AT/RT3, p = 0.001; LIN28B siRNA-2 in SNU-AT/RT4, p = 0.02; Fig. 3a; Additional file 1: Table S1). The inhibition of LIN28B suppressed CCND1 expression but enhanced CDKN1C expression (Fig. 3a; Additional file 1: Table S1). Western blot analysis after LIN28B siRNA treatment further confirmed the RT-qPCR results (Fig. 3b; Additional file 1: Table S1). The increased expression of pri-let-7g and mature let-7g miRNA were observed after LIN28B knockdown (Fig. 3c; Additional file 1: Table S1).Fig. 3


LIN28B is highly expressed in atypical teratoid/rhabdoid tumor (AT/RT) and suppressed through the restoration of SMARCB1.

Choi SA, Kim SK, Lee JY, Wang KC, Lee C, Phi JH - Cancer Cell Int. (2016)

Effect of LIN28B knockdown on AT/RT cells. The level of LIN28B mRNA and protein was effectively inhibited after the transfection of LIN28B-siRNAs. a RT-qPCR and b western blot analysis showed that LIN28B knockdown reduced CCND1 expression and enhanced CDKN1C expression. c The increased expression of pre-leg-7g and mature let-7g miRNA was observed after LIN28B knockdown. *P < 0.05; **P < 0.01; ***P < 0.01. Error bars represent ±SD
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Related In: Results  -  Collection

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Fig3: Effect of LIN28B knockdown on AT/RT cells. The level of LIN28B mRNA and protein was effectively inhibited after the transfection of LIN28B-siRNAs. a RT-qPCR and b western blot analysis showed that LIN28B knockdown reduced CCND1 expression and enhanced CDKN1C expression. c The increased expression of pre-leg-7g and mature let-7g miRNA was observed after LIN28B knockdown. *P < 0.05; **P < 0.01; ***P < 0.01. Error bars represent ±SD
Mentions: To determine the role of LIN28B in AT/RT, we performed siRNA knockdown experiments using two distinct siRNA constructs (LIN28B siRNA-1 and LIN28B siRNA-2). The knockdown efficiency was confirmed using RT-qPCR and western blot analysis in two primary cultured AT/RT cell lines (SNU-AT/RT3 and SNU-AT/RT4). The LIN28B siRNAs effectively degraded LIN28B (LIN28B siRNA-1 in SNU-AT/RT3, p = 0.009; LIN28B siRNA-1 in SNU-AT/RT4, p = 0.002; LIN28B siRNA-2 in SNU-AT/RT3, p = 0.001; LIN28B siRNA-2 in SNU-AT/RT4, p = 0.02; Fig. 3a; Additional file 1: Table S1). The inhibition of LIN28B suppressed CCND1 expression but enhanced CDKN1C expression (Fig. 3a; Additional file 1: Table S1). Western blot analysis after LIN28B siRNA treatment further confirmed the RT-qPCR results (Fig. 3b; Additional file 1: Table S1). The increased expression of pri-let-7g and mature let-7g miRNA were observed after LIN28B knockdown (Fig. 3c; Additional file 1: Table S1).Fig. 3

Bottom Line: The knockdown of LIN28B decreased cell viability and proliferation, induced cell cycle arrest, and reduced migration in primary cultured AT/RT cells.The restoration of SMARCB1 in AT/RT cells decreased the expression of LIN28B and CCND1.These results show that LIN28B might be regulated through SMARCB1; the loss of SMARCB1 protein in AT/RT results in the unopposed expression of LIN28B and related oncogenes such as CCND1, leading to tumorigenesis.

View Article: PubMed Central - PubMed

Affiliation: Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, 101 Daehakro, Jongno-gu, Seoul, 03080 Republic of Korea.

ABSTRACT

Background: Atypical teratoid/rhabdoid tumor (AT/RT) is a highly malignant brain tumor that almost exclusively develops in young children. AT/RT belongs to the embryonal brain tumor group, comprising primitive tumors recapitulating the early development of the central nervous system during embryogenesis. The loss of SMARCB1 protein expression is a hallmark of AT/RT pathogenesis. LIN28A/B is a key gene in embryonic development and for the maintenance of pluripotency in stem cells. LIN28B might be an important co-player in AT/RT pathogenesis, considering the primitive nature and young age onset of AT/RT.

Methods: We explored the expression patterns of LIN28B in AT/RT and compared it with the expression in cortical dysplasia and medulloblastoma. The functional role of LIN28B was assessed using LIN28B-siRNAs in primary cultured AT/RT cells.

Results: LIN28B is highly expressed in AT/RT compared with medulloblastoma and other embryonal tumors, whereas primary let-7g miRNA is down-regulated. AT/RT also showed higher expression of CCND1 and MYC, and lower expression of CDKN1C. The suppression of CCND1 expression and enhanced expression of CDKN1C were also observed. The knockdown of LIN28B decreased cell viability and proliferation, induced cell cycle arrest, and reduced migration in primary cultured AT/RT cells. Furthermore, we showed that the knockdown of LIN28B decreased the expression of other pluripotency-related genes (OCT4 and NANOG) and the mesenchymal-epithelial transition signature. We also transfected wild-type SMARCB1 into primary cultured AT/RT cells. The restoration of SMARCB1 in AT/RT cells decreased the expression of LIN28B and CCND1.

Conclusions: These results show that LIN28B might be regulated through SMARCB1; the loss of SMARCB1 protein in AT/RT results in the unopposed expression of LIN28B and related oncogenes such as CCND1, leading to tumorigenesis. Therefore, the strategic role of LIN28B in AT/RT might be utilized as an important therapeutic target.

No MeSH data available.


Related in: MedlinePlus