Hypoxia-inducible factor–dependent breast cancer–mesenchymal stem cell bidirectional signaling promotes metastasis
Pallavi Chaturvedi, … , Andre Levchenko, Gregg L. Semenza
Pallavi Chaturvedi, … , Andre Levchenko, Gregg L. Semenza
Published December 17, 2012
Citation Information: J Clin Invest. 2013;123(1):189-205. https://doi.org/10.1172/JCI64993.
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Research Article

Hypoxia-inducible factor–dependent breast cancer–mesenchymal stem cell bidirectional signaling promotes metastasis

Abstract

Metastasis involves critical interactions between cancer and stromal cells. Intratumoral hypoxia promotes metastasis through activation of hypoxia-inducible factors (HIFs). We demonstrate that HIFs mediate paracrine signaling between breast cancer cells (BCCs) and mesenchymal stem cells (MSCs) to promote metastasis. In a mouse orthotopic implantation model, MSCs were recruited to primary breast tumors and promoted BCC metastasis to LNs and lungs in a HIF-dependent manner. Coculture of MSCs with BCCs augmented HIF activity in BCCs. Additionally, coculture induced expression of the chemokine CXCL10 in MSCs and the cognate receptor CXCR3 in BCCs, which was augmented by hypoxia. CXCR3 expression was blocked in cocultures treated with neutralizing antibody against CXCL10. Conversely, CXCL10 expression was blocked in MSCs cocultured with BCCs that did not express CXCR3 or HIFs. MSC coculture did not enhance the metastasis of HIF-deficient BCCs. BCCs and MSCs expressed placental growth factor (PGF) and its cognate receptor VEGFR1, respectively, in a HIF-dependent manner, and CXCL10 expression by MSCs was dependent on PGF expression by BCCs. PGF promoted metastasis of BCCs and also facilitated homing of MSCs to tumors. Thus, HIFs mediate complex and bidirectional paracrine signaling between BCCs and MSCs that stimulates breast cancer metastasis.

Authors

Pallavi Chaturvedi, Daniele M. Gilkes, Carmen Chak Lui Wong, Kshitiz, Weibo Luo, Huafeng Zhang, Hong Wei, Naoharu Takano, Luana Schito, Andre Levchenko, Gregg L. Semenza

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Figure 9

HIF regulates PGF and VEGFR1 expression and facilitates bidirectional signaling.

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HIF regulates PGF and VEGFR1 expression and facilitates bidirectional si...
(A and B) BCCs, MSCs, or BCCs+MSCs were cultured at 20% or 1% O2 for 48 hours. PGF and VEGFR1 mRNA levels, determined by RT-qPCR, were normalized to those in BCCs at 20% O2. *P < 0.05 vs. 20% BCCs; #P < 0.01 vs. 20% BCCs+MSCs, ANOVA. (C and D) EV cells, DKD cells, MSCs, EV+MSCs, and DKD+MSCs were exposed to 20% or 1% O2 for 48 hours. PGF and VEGFR1 mRNA levels were normalized to those in BCCs at 20% O2. #P < 0.01 vs. 1% EV+MSCs. (E and F) GFP+ BCCs were cocultured with MSCs at 20% or 1% O2 for 48 hours, followed by FACS based on GFP fluorescence of BCCs and CD105 immunofluorescence of MSCs. RNA was extracted from flow-sorted cells for analysis of PGF and VEGFR1 expression. *P < 0.05 vs. 20% MSCs or BCCs alone; #P < 0.01 vs. 1% MSCs or BCCs alone. (G) CM was isolated from EV cells, DKD cells, MSCs, EV+MSCs, and DKD+MSCs cultured for 48 hours at 20% or 1% O2. ELISA was performed to determine PGF protein levels in CM (mean ± SEM; n = 3). *P < 0.05, **P < 0.001 vs. 20% EV; #P < 0.01 vs. 1% EV+MSCs, ANOVA. (H) NTC, shPGF-1, and shPGF-2 MDA-231 subclones were cultured alone or with MSCs at 20% or 1% O2 for 48 hours. CXCL10 mRNA expression was analyzed by RT-qPCR (mean ± SEM; n = 3). **P < 0.001 vs. 1% NTC+MSCs, ANOVA.