Inhibition of DYRK1A destabilizes EGFR and reduces EGFR-dependent glioblastoma growth
Natividad Pozo, … , Juan M. Sepúlveda, Pilar Sánchez-Gómez
Natividad Pozo, … , Juan M. Sepúlveda, Pilar Sánchez-Gómez
Published May 1, 2013
Citation Information: J Clin Invest. 2013;123(6):2475-2487. https://doi.org/10.1172/JCI63623.
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Research Article Oncology

Inhibition of DYRK1A destabilizes EGFR and reduces EGFR-dependent glioblastoma growth

Abstract

Glioblastomas (GBMs) are very aggressive tumors that are resistant to conventional chemo- and radiotherapy. New molecular therapeutic strategies are required to effectively eliminate the subpopulation of GBM tumor–initiating cells that are responsible for relapse. Since EGFR is altered in 50% of GBMs, it represents one of the most promising targets; however, EGFR kinase inhibitors have produced poor results in clinical assays, with no clear explanation for the observed resistance. We uncovered a fundamental role for the dual-specificity tyrosine phosphorylation–regulated kinase, DYRK1A, in regulating EGFR in GBMs. We found that DYRK1A was highly expressed in these tumors and that its expression was correlated with that of EGFR. Moreover, DYRK1A inhibition promoted EGFR degradation in primary GBM cell lines and neural progenitor cells, sharply reducing the self-renewal capacity of normal and tumorigenic cells. Most importantly, our data suggest that a subset of GBMs depends on high surface EGFR levels, as DYRK1A inhibition compromised their survival and produced a profound decrease in tumor burden. We propose that the recovery of EGFR stability is a key oncogenic event in a large proportion of gliomas and that pharmacological inhibition of DYRK1A could represent a promising therapeutic intervention for EGFR-dependent GBMs.

Authors

Natividad Pozo, Cristina Zahonero, Paloma Fernández, Jose M. Liñares, Angel Ayuso, Masatoshi Hagiwara, Angel Pérez, Jose R. Ricoy, Aurelio Hernández-Laín, Juan M. Sepúlveda, Pilar Sánchez-Gómez

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Figure 4

Conditional DYRK1A interference affects EGFR levels and the tumorigenic capacity of GBM-TICs.

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Conditional DYRK1A interference affects EGFR levels and the tumorigenic ...
(A) RT-PCR analysis of DYRK1A transcripts 3 days after shDYRK1A induction with doxycycline (Dox). (B) Flow cytometric analysis of the amount of EGFR-positive cells 3 days after shDYRK1A induction. (C) RT-PCR analysis of EGFR transcripts 3 days after shDYRK1A induction. (D) Quantification of the capacity to form secondary spheres after doxycycline removal. (E) 50,000 GBM5 cells infected with inducible shDYRK1A (GBM5-ishDYRK1A) cells were implanted intracranially into nude mice, and 3 weeks later, doxycycline (indicated with an arrow) was added to the drinking water of 1 group of mice. Animal survival was evaluated using a Kaplan-Meier survival curve, and the differences in survival times were analyzed with a log-rank test (n = 4; P = 0.0316). (F) GBM5-ishDYRK1A cells (3.5 × 106) were injected into the flanks of nude mice. Two weeks later, doxycycline was added to the drinking water of 1 group of mice, and tumor size was measured once every 4–5 days. Graph represents the tumor volume after doxycycline addition. (G) Western blot analysis of DYRK1A and EGFR protein levels in control and doxycycline-treated tumors. (H) RT-PCR analysis of DYRK1A and EGFR transcript levels in control and doxycycline-treated tumors. (I) Number of BrdU-positive cells in the flank tumors. (J) Amount of cells with activated caspase 3 in the flank tumors. *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001.