Ligand-dependent notch signaling is involved in tumor initiation and tumor maintenance in pancreatic cancer

Michael E. Mullendore, Jan Bart Koorstra, Yue Ming Li, G. Johan Offerhaus, Xing Fan, Clark M. Henderson, William Matsui, Charles G. Eberhart, Anirban Maitra, Georg Feldmann

Research output: Contribution to journalArticle

Abstract

Purpose: Aberrant activation of the Notch signaling pathway is commonly observed in human pancreatic cancer, although the mechanism(s) for this activation has not been elucidated. Experimental Design: A panel of 20 human pancreatic cancer cell lines was profiled for the expression of Notch pathway-related ligands, receptors, and target genes. Disruption of intracellular Notch signaling, either genetically by RNA interference targeting NOTCH1 or pharmacologically by means of the g-secretase inhibitor GSI-18, was used for assessing requirement of Notch signaling in pancreatic cancer initiation and maintenance. Results: Striking overexpression of Notch ligand transcripts was detectable in the vast majority of pancreatic cancer cell lines, most prominently JAGGED2 (18 of 20 cases, 90%) and DLL4 (10 of 20 cases, 50%). In two cell lines, genomic amplification of the DLL3 locus was observed, mirrored by overexpression of DLL3 transcripts. In contrast, coding region mutations of NOTCH1 or NOTCH2 were not observed. Genetic and pharmacologic inhibition of Notch signaling mitigated anchorage-independent growth in pancreatic cancer cells, confirming that sustained Notch activation is a requirement for pancreatic cancer maintenance. Further, transient pretreatment of pancreatic cancer cells with GSI-18 resulted in depletion in the proportion of tumor-initiating aldehyde dehydrogenase-expressing subpopulation and was associated with inhibition of colony formation in vitro and xenograft engraftment in vivo, underscoring a requirement for the Notch-dependent aldehyde dehydrogenase-expressing cells in pancreatic cancer initiation. Conclusions: Our studies confirm that Notch activation is almost always ligand dependent in pancreatic cancer, and inhibition of Notch signaling is a promising therapeutic strategy in this malignancy.

Original languageEnglish (US)
Pages (from-to)2291-2301
Number of pages11
JournalClinical Cancer Research
Volume15
Issue number7
DOIs
StatePublished - Apr 1 2009

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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    Mullendore, M. E., Koorstra, J. B., Li, Y. M., Offerhaus, G. J., Fan, X., Henderson, C. M., Matsui, W., Eberhart, C. G., Maitra, A., & Feldmann, G. (2009). Ligand-dependent notch signaling is involved in tumor initiation and tumor maintenance in pancreatic cancer. Clinical Cancer Research, 15(7), 2291-2301. https://doi.org/10.1158/1078-0432.CCR-08-2004