Up-regulation of pro-inflammatory genes as adaptation to hypoxia in MCF-7 cells and in human mammary invasive carcinoma microenvironment.
The role of tumor cells in synthesizing pro-inflammatory molecules is still controversial. Here we report that hypoxic treatment of the MCF-7 human mammary adenocarcinoma cell line induced activation of hypoxia-inducible factor 1alpha (HIF-1alpha) and nuclear factor-kappa B (NF-kappaB). Importantly, hypoxia regulated expression of alarmin receptors such as the receptor for advanced glycation end products (RAGE) and the purinoreceptor (P2X7R), and up-regulated inflammatory response (IR) genes such as the inducible enzymes nitric oxide synthase (NOS2), cycloxygenase (COX2), and the acute-phase protein pentraxin-3 (PTX3). Hypoxia also stimulated chemokine (C-X-C motif) receptor 4 (CXCR4) mRNA synthesis. In fact, the CXCR4 ligand stromal-derived factor-1alpha (SDF-1alpha) increased invasion and migration of hypoxic MCF-7 cells. Inhibition of HIF-1alpha by chetomin and NF-kappaB by parthenolide reduced mRNA and protein expression of the studied molecules and prevented invasion of hypoxic MCF-7 cells. Moreover, solid invasive mammary tumor microenvironment was analyzed after laser-capture microdissection (LCMD) comparing tumor versus host normal tissue. Nuclear translocation of HIF-1alpha and NF-kappaB and up-regulation of IR, CXCR4, estrogen receptor alpha (ERalpha), and epithelial growth factor receptor (EGFR) was observed in tumor but not in host normal tissue in the absence of a local inflammatory leukocyte infiltrate. We conclude that under hypoxic conditions MCF-7 cells acquire a pro-inflammatory phenotype, and that solid human mammary carcinoma evidenced a similar activation of HIF-1alpha, NF-kappaB, and IR genes in malignant tumor cells as compared to the normal host tissues. We suggest a role for IR activation in the malignant progression of transformed cells.
Department of Cellular and Molecular Pathology, IRCCS San Raffaele Pisana, Rome, Italy.
Marco
M
Tafani
Andrea
A
Russo
Maura
M
Di Vito
Patrizio
P
Sale
Laura
L
Pellegrini
Luana
L
Schito
Stefano
S
Gentileschi
Roberto
R
Bracaglia
Ferdinando
F
Marandino
Enrico
E
Garaci
Matteo A
MA
Russo
D000368:Aged; D001943:Breast Neoplasms / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D015687:Cell Hypoxia / Q000235:genetics*; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D007249:Inflammation / Q000235:genetics; D008875:Middle Aged; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D009361:Neoplasm Invasiveness / Q000235:genetics; D015854:Up-Regulation
C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D016328:NF-kappa B