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 6

Pharmacological inhibition of DYRK1A impairs the self-renewal capacity of EGFR-expressing GBM-TICs.

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Pharmacological inhibition of DYRK1A impairs the self-renewal capacity o...
GBM primary cells were incubated in the presence of (A) harmine or (B) INDY, and 3 days later, the spheres were dissociated and replated in the absence of the drug. A 20-μm concentration was chosen based on SVZ-NSC behavior (Figure 5A and Supplemental Figure 7). The number of secondary spheres is represented in the graphs. (C) 50,000 GBM5 cells were implanted intracranially into nude mice. Two weeks later, the animals started to receive i.p. injections of saline (Control) or harmine (15 mg/kg/day, 5 days per week; indicated by an arrow). Animal survival was evaluated using a Kaplan-Meier survival curve, and the differences in survival times were analyzed with a log-rank test (n = 5; P = 0.09). (D) Number of mitotic cells in control or harmine-treated tumor tissue. (E) Representative images of activated caspase 3 staining in control and harmine-treated tumor tissue. (F) Representative images of EGFR staining in control and harmine-treated tumor tissue. (G) Correlation between the amount of membrane EGFR present in the different GBM-TIC lines and the percentage of self-renewal inhibition induced by harmine. (H) Percentage of self-renewal inhibition induced by harmine in low- or high-passage GBM3 cells. Western blot on the right shows the amount of EGFR and DYRK1A expressed by low- and high-passage GBM3 cells. Scale bar: 40 μm. *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001.