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miR-146a promotes the initiation and progression of melanoma by activating Notch signaling.

Forloni M, Dogra SK, Dong Y, Conte D, Ou J, Zhu LJ, Deng A, Mahalingam M, Green MR, Wajapeyee N - Elife (2014)

Bottom Line: We show these oncogenic activities are due to miR-146a targeting the NUMB mRNA, a repressor of Notch signaling.Previous studies have shown that pre-miR-146a contains a single nucleotide polymorphism (C>G rs2910164).We find that the ability of pre-miR-146a/G to activate Notch signaling and promote oncogenesis is substantially higher than that of pre-miR-146a/C.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Yale University School of Medicine, New Haven, United States.

ABSTRACT
Oncogenic mutations in BRAF and NRAS occur in 70% of melanomas. In this study, we identify a microRNA, miR-146a, that is highly upregulated by oncogenic BRAF and NRAS. Expression of miR-146a increases the ability of human melanoma cells to proliferate in culture and form tumors in mice, whereas knockdown of miR-146a has the opposite effects. We show these oncogenic activities are due to miR-146a targeting the NUMB mRNA, a repressor of Notch signaling. Previous studies have shown that pre-miR-146a contains a single nucleotide polymorphism (C>G rs2910164). We find that the ability of pre-miR-146a/G to activate Notch signaling and promote oncogenesis is substantially higher than that of pre-miR-146a/C. Analysis of melanoma cell lines and matched patient samples indicates that during melanoma progression pre-miR-146a/G is enriched relative to pre-miR-146a/C, resulting from a C-to-G somatic mutation in pre-miR-146a/C. Collectively, our results reveal a central role for miR-146a in the initiation and progression of melanoma. DOI: http://dx.doi.org/10.7554/eLife.01460.001.

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Related in: MedlinePlus

Ectopic expression of BRAFV600E in WI-38 and IMR-90 cells stimulates miR-146a expression.qRT-PCR analysis of miR-146a expression in WI-38 or IMR-90 cells transduced with BRAFV600E (gray) or Vector control (black) retrovirus particles. Quiescent cells were used as a control (light gray).DOI:http://dx.doi.org/10.7554/eLife.01460.004
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fig1s1: Ectopic expression of BRAFV600E in WI-38 and IMR-90 cells stimulates miR-146a expression.qRT-PCR analysis of miR-146a expression in WI-38 or IMR-90 cells transduced with BRAFV600E (gray) or Vector control (black) retrovirus particles. Quiescent cells were used as a control (light gray).DOI:http://dx.doi.org/10.7554/eLife.01460.004

Mentions: To identify possible BRAFV600E-regulated miRNAs, we generated miRNA libraries from primary lung fibroblast WI-38 cells transduced with retrovirus expressing BRAFV600E or an empty vector and performed deep sequencing analysis. To rule out miRNAs that are altered due to cell cycle arrest, we also sequenced a miRNA library generated using quiescent WI-38 cells (Figure 1A). Our analysis identified miR-146a as the most upregulated miRNA by BRAFV600E (Figure 1B). To confirm that miR-146a is a target of BRAFV600E, we transduced human fibroblasts WI-38, IMR-90 and primary human melanocytes (hereafter referred to as melanocytes) with retroviruses expressing BRAFV600E. We found that BRAFV600E activates miR-146a expression in WI-38 as well as in IMR-90 and melanocytes (Figure 1—figure supplement 1, Figure 1C).10.7554/eLife.01460.003Figure 1.BRAFV600E and NRASQ61K upregulate miR-146a expression.


miR-146a promotes the initiation and progression of melanoma by activating Notch signaling.

Forloni M, Dogra SK, Dong Y, Conte D, Ou J, Zhu LJ, Deng A, Mahalingam M, Green MR, Wajapeyee N - Elife (2014)

Ectopic expression of BRAFV600E in WI-38 and IMR-90 cells stimulates miR-146a expression.qRT-PCR analysis of miR-146a expression in WI-38 or IMR-90 cells transduced with BRAFV600E (gray) or Vector control (black) retrovirus particles. Quiescent cells were used as a control (light gray).DOI:http://dx.doi.org/10.7554/eLife.01460.004
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3927633&req=5

fig1s1: Ectopic expression of BRAFV600E in WI-38 and IMR-90 cells stimulates miR-146a expression.qRT-PCR analysis of miR-146a expression in WI-38 or IMR-90 cells transduced with BRAFV600E (gray) or Vector control (black) retrovirus particles. Quiescent cells were used as a control (light gray).DOI:http://dx.doi.org/10.7554/eLife.01460.004
Mentions: To identify possible BRAFV600E-regulated miRNAs, we generated miRNA libraries from primary lung fibroblast WI-38 cells transduced with retrovirus expressing BRAFV600E or an empty vector and performed deep sequencing analysis. To rule out miRNAs that are altered due to cell cycle arrest, we also sequenced a miRNA library generated using quiescent WI-38 cells (Figure 1A). Our analysis identified miR-146a as the most upregulated miRNA by BRAFV600E (Figure 1B). To confirm that miR-146a is a target of BRAFV600E, we transduced human fibroblasts WI-38, IMR-90 and primary human melanocytes (hereafter referred to as melanocytes) with retroviruses expressing BRAFV600E. We found that BRAFV600E activates miR-146a expression in WI-38 as well as in IMR-90 and melanocytes (Figure 1—figure supplement 1, Figure 1C).10.7554/eLife.01460.003Figure 1.BRAFV600E and NRASQ61K upregulate miR-146a expression.

Bottom Line: We show these oncogenic activities are due to miR-146a targeting the NUMB mRNA, a repressor of Notch signaling.Previous studies have shown that pre-miR-146a contains a single nucleotide polymorphism (C>G rs2910164).We find that the ability of pre-miR-146a/G to activate Notch signaling and promote oncogenesis is substantially higher than that of pre-miR-146a/C.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Yale University School of Medicine, New Haven, United States.

ABSTRACT
Oncogenic mutations in BRAF and NRAS occur in 70% of melanomas. In this study, we identify a microRNA, miR-146a, that is highly upregulated by oncogenic BRAF and NRAS. Expression of miR-146a increases the ability of human melanoma cells to proliferate in culture and form tumors in mice, whereas knockdown of miR-146a has the opposite effects. We show these oncogenic activities are due to miR-146a targeting the NUMB mRNA, a repressor of Notch signaling. Previous studies have shown that pre-miR-146a contains a single nucleotide polymorphism (C>G rs2910164). We find that the ability of pre-miR-146a/G to activate Notch signaling and promote oncogenesis is substantially higher than that of pre-miR-146a/C. Analysis of melanoma cell lines and matched patient samples indicates that during melanoma progression pre-miR-146a/G is enriched relative to pre-miR-146a/C, resulting from a C-to-G somatic mutation in pre-miR-146a/C. Collectively, our results reveal a central role for miR-146a in the initiation and progression of melanoma. DOI: http://dx.doi.org/10.7554/eLife.01460.001.

Show MeSH
Related in: MedlinePlus