May the remodeling of the Ca2+ toolkit in endothelial progenitor cells derived from cancer patients suggest alternative targets for anti-angiogenic treatment?

Francesco Moccia, Valentina Poletto

Research output: Contribution to journalArticle

Abstract

Endothelial progenitor cells (EPCs) may be recruited from bone marrow to sustain the metastatic switch in a number of solid cancers, including breast cancer (BC) and renal cellular carcinoma (RCC). Preventing EPC mobilization causes tumor shrinkage. Novel anti-angiogenic treatments have been introduced in therapy to inhibit VEGFR-2 signaling; unfortunately, these drugs blocked tumor angiogenesis in pre-clinical murine models, but resulted far less effective in human patients. Understanding the molecular mechanisms driving EPC proliferation and tubulogenesis in cancer patients could outline novel targets for alternative anti-angiogenic treatments. Store-operated Ca2+ entry (SOCE) regulates the growth of human EPCs, and it is mediated by the interaction between the endoplasmic reticulum Ca2+-sensor, Stim1, and the plasmalemmal Ca2+ channels, Orai1 and TRPC1. EPCs do not belong to the neoplastic clone: thus, unlike tumor endothelium and neoplastic cells, they should not remodel their Ca2+ toolkit in response to tumor microenvironment. However, our recent work demonstrated that EPCs isolated from naïve RCC patients (RCC-EPCs) undergo a dramatic remodeling of their Ca2+ toolkit by displaying a remarkable drop in the endoplasmic reticulum Ca2+ content, by down-regulating the expression of inositol-1,4,5-receptors (InsP3Rs), and by up-regulating Stim1, Orai1 and TRPC1. Moreover, EPCs are dramatically less sensitive to VEGF stimulation both in terms of Ca2+ signaling and of gene expression when isolated from tumor patients. Conversely, the pharmacological abolition of SOCE suppresses proliferation in these cells. These results question the suitability of VEGFR-2 as a therapeutically relevant target for anti-angiogenic treatments and hint at Orai1 and TRPC1 as more promising alternatives. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.

Original languageEnglish
Pages (from-to)1958-1973
Number of pages16
JournalBiochimica et Biophysica Acta - Molecular Cell Research
Volume1853
Issue number9
DOIs
Publication statusPublished - Dec 31 2015

Keywords

  • Endothelial progenitor cel
  • Orai1
  • Stim1
  • TRPC1
  • Tumor vascularization
  • Vascular endothelial growth facto

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology
  • Medicine(all)

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