Kras activation in p53-deficient myoblasts results in high-grade sarcoma formation with impaired myogenic differentiation

Oncotarget. 2015 Jun 10;6(16):14220-32. doi: 10.18632/oncotarget.3856.

Abstract

While genomic studies have improved our ability to classify sarcomas, the molecular mechanisms involved in the formation and progression of many sarcoma subtypes are unknown. To better understand developmental origins and genetic drivers involved in rhabdomyosarcomagenesis, we describe a novel sarcoma model system employing primary murine p53-deficient myoblasts that were isolated and lentivirally transduced with KrasG12D. Myoblast cell lines were characterized and subjected to proliferation, anchorage-independent growth and differentiation assays to assess the effects of transgenic KrasG12D expression. KrasG12D overexpression transformed p53-/- myoblasts as demonstrated by an increased anchorage-independent growth. Induction of differentiation in parental myoblasts resulted in activation of key myogenic regulators. In contrast, Kras-transduced myoblasts had impaired terminal differentiation. p53-/- myoblasts transformed by KrasG12D overexpression resulted in rapid, reproducible tumor formation following orthotopic injection into syngeneic host hindlimbs. Pathological analysis revealed high-grade sarcomas with myogenic differentiation based on the expression of muscle-specific markers, such as Myod1 and Myog. Gene expression patterns of murine sarcomas shared biological pathways with RMS gene sets as determined by gene set enrichment analysis (GSEA) and were 61% similar to human RMS as determined by metagene analysis. Thus, our novel model system is an effective means to model high-grade sarcomas along the RMS spectrum.

Keywords: Kras; mouse models of cancer; myogenic differentiation; rhabdomyosarcoma; sarcoma.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Differentiation / physiology
  • Cell Line
  • Cell Proliferation / physiology
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Myoblasts / enzymology
  • Myoblasts / metabolism*
  • Myoblasts / pathology*
  • Proto-Oncogene Proteins p21(ras) / genetics
  • Proto-Oncogene Proteins p21(ras) / metabolism*
  • Sarcoma / genetics
  • Sarcoma / metabolism*
  • Sarcoma / pathology

Substances

  • KRAS protein, human
  • Hras protein, mouse
  • Proto-Oncogene Proteins p21(ras)