IGF1R inhibition in mammary epithelia promotes canonical Wnt signaling and Wnt1-driven tumors

Lauren M. Rota, Lidia Albanito, Marcus E. Shin, Corey L. Goyeneche, Sain Shushanov, Emily J. Gallagher, Derek Le Roith, Deborah A. Lazzarino, Teresa L. Wood

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Triple-negative breast cancer (TNBC) is an aggressive disease subtype that, unlike other subtypes, lacks an effective targeted therapy. Inhibitors of the insulin-like growth factor receptor (IGF1R) have been considered for use in treating TNBC. Here, we provide genetic evidence that IGF1R inhibition promotes development of Wnt1-mediated murine mammary tumors that offer a model of TNBC. We found that in a double transgenic mouse model carrying activated Wnt1 and mutant Igf1r, a reduction in IGF1R signaling reduced tumor latency and promoted more aggressive phenotypes. These tumors displayed a squamous phenotype with increased expression of keratins 5/6 and β-catenin. Notably, cell lineage analyses revealed an increase in basal (CD29hi/CD24+) and luminal (CD24+/CD61+/CD291o) progenitor cell populations, along with increased Nanog expression and decreased Elf5 expression. In these doubly transgenic mice, lung metastases developed with characteristics of the primary tumors, unlike MMTV-Wnt1 mice. Mechanistic investigations showed that pharmacologic inhibition of the IGF1R in vitro was sufficient to increase the tumorsphere-forming efficiency of MMTV-Wnt1 tumor cells. Tumors from doubly transgenic mice also exhibited an increase in the expression ratio of the IGF-II-sensitive, A isoform of the insulin receptor versus the IR-B isoform, which when stimulated in vitro resulted in enhanced expression of β-catenin. Overall, our results revealed that in Wnt-driven tumors, an attenuation of IGF1R signaling accelerates tumorigenesis and promotes more aggressive phenotypes with potential implications for understanding TNBC pathobiology and treatment.

Original languageEnglish (US)
Pages (from-to)5668-5679
Number of pages12
JournalCancer Research
Volume74
Issue number19
DOIs
StatePublished - Oct 1 2014

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research

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