Identification of FGFR4-activating mutations in human rhabdomyosarcomas that promote metastasis in xenotransplanted models
James G. Taylor VI, … , Stephen J. Chanock, Javed Khan
James G. Taylor VI, … , Stephen J. Chanock, Javed Khan
Published October 5, 2009
Citation Information: J Clin Invest. 2009;119(11):3395-3407. https://doi.org/10.1172/JCI39703.
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Research Article Oncology

Identification of FGFR4-activating mutations in human rhabdomyosarcomas that promote metastasis in xenotransplanted models

Abstract

Rhabdomyosarcoma (RMS) is a childhood cancer originating from skeletal muscle, and patient survival is poor in the presence of metastatic disease. Few determinants that regulate metastasis development have been identified. The receptor tyrosine kinase FGFR4 is highly expressed in RMS tissue, suggesting a role in tumorigenesis, although its functional importance has not been defined. Here, we report the identification of mutations in FGFR4 in human RMS tumors that lead to its activation and present evidence that it functions as an oncogene in RMS. Higher FGFR4 expression in RMS tumors was associated with advanced-stage cancer and poor survival, while FGFR4 knockdown in a human RMS cell line reduced tumor growth and experimental lung metastases when the cells were transplanted into mice. Moreover, 6 FGFR4 tyrosine kinase domain mutations were found among 7 of 94 (7.5%) primary human RMS tumors. The mutants K535 and E550 increased autophosphorylation, Stat3 signaling, tumor proliferation, and metastatic potential when expressed in a murine RMS cell line. These mutants also transformed NIH 3T3 cells and led to an enhanced metastatic phenotype. Finally, murine RMS cell lines expressing the K535 and E550 FGFR4 mutants were substantially more susceptible to apoptosis in the presence of a pharmacologic FGFR inhibitor than the control cell lines expressing the empty vector or wild-type FGFR4. Together, our results demonstrate that mutationally activated FGFR4 acts as an oncogene, and these are what we believe to be the first known mutations in a receptor tyrosine kinase in RMS. These findings support the potential therapeutic targeting of FGFR4 in RMS.

Authors

James G. Taylor VI, Adam T. Cheuk, Patricia S. Tsang, Joon-Yong Chung, Young K. Song, Krupa Desai, Yanlin Yu, Qing-Rong Chen, Kushal Shah, Victoria Youngblood, Jun Fang, Su Young Kim, Choh Yeung, Lee J. Helman, Arnulfo Mendoza, Vu Ngo, Louis M. Staudt, Jun S. Wei, Chand Khanna, Daniel Catchpoole, Stephen J. Qualman, Stephen M. Hewitt, Glenn Merlino, Stephen J. Chanock, Javed Khan

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Figure 3

FGFR4 suppression leads to inhibition of in vivo growth and lung metastasis.

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FGFR4 suppression leads to inhibition of in vivo growth and lung metasta...
(A) Intramuscular injection of RH30 with inducible anti-FGFR4 shRNA resulted in significantly smaller tumors in the FGFR4-suppressed mice on day 31 using bioluminescent imaging (n = 6 mice per group, Mann-Whitney test). (B) Representative mice with intramuscular injection on day 31. The intensity of tumor cells expressing luciferase is quantified as photons/second/cm2/steridian (p/s/cm2/sr). (C) Representative IVVM images showing decreased RH30 cells in the lungs at 24 hours when FGFR4 was suppressed. (D) Quantification of IVVM early pulmonary metastases at 1 and 24 hours showed significantly fewer malignant cells remaining in the lungs with FGFR4 suppression (normalized mean values ± SEM; n = 5 mice per group; Mann-Whitney test). (E) Representative mice with intravenous injection showed decreased tumor signal in the lungs with FGFR4 suppression on day 74. (F) Intravenous injection of the same cells resulted in significantly fewer lesions in the lungs on day 74 in the FGFR4-suppressed mice (normalized for tumor growth rate by taking the ratio of pulmonary to pelvic tumor signal; n = 10 mice per group, Mann-Whitney test).