IL-6 triggers malignant features in mammospheres from human ductal breast carcinoma and normal mammary gland
Pasquale Sansone, … , Pasquale Chieco, Massimiliano Bonafè
Pasquale Sansone, … , Pasquale Chieco, Massimiliano Bonafè
Published December 3, 2007
Citation Information: J Clin Invest. 2007;117(12):3988-4002. https://doi.org/10.1172/JCI32533.
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Research Article

IL-6 triggers malignant features in mammospheres from human ductal breast carcinoma and normal mammary gland

Abstract

High serum levels of IL-6 correlate with poor outcome in breast cancer patients. However, no data are available on the relationship between IL-6 and mammary stem/progenitor cells, which may fuel the genesis of breast cancer in vivo. Herein, we address this issue in the MCF-7 breast cancer cell line and in primary human mammospheres (MS), multicellular structures enriched in stem/progenitor cells of the mammary gland. MS from node invasive breast carcinoma tissues expressed IL-6 mRNA at higher levels than did MS from matched non-neoplastic mammary glands. In addition, IL-6 mRNA was detected only in basal-like breast carcinoma tissues, an aggressive breast carcinoma variant showing stem cell features. IL-6 treatment triggered Notch-3–dependent upregulation of the Notch ligand Jagged-1 and promotion of MS and MCF-7–derived spheroid growth. Moreover, IL-6 induced Notch-3–dependent upregulation of the carbonic anhydrase IX gene and promoted a hypoxia-resistant/invasive phenotype in MCF-7 cells and MS. Finally, autocrine IL-6 signaling relied upon Notch-3 activity to sustain the aggressive features of MCF-7–derived hypoxia-selected cells. In conclusion, these data support the hypothesis that IL-6 induces malignant features in Notch-3–expressing stem/progenitor cells from human ductal breast carcinoma and normal mammary gland.

Authors

Pasquale Sansone, Gianluca Storci, Simona Tavolari, Tiziana Guarnieri, Catia Giovannini, Mario Taffurelli, Claudio Ceccarelli, Donatella Santini, Paola Paterini, Kenneth B. Marcu, Pasquale Chieco, Massimiliano Bonafè

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Figure 6

The IL-6/Notch-3/CA-IX axis promotes hypoxia survival.

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The IL-6/Notch-3/CA-IX axis promotes hypoxia survival. (A) MCF-7 cells i...
(A) MCF-7 cells in the presence or absence of DFX (100 μM for 48 hours) and in the presence or absence of anti–IL-6 (1.5 μg/ml for 24 hours), with transient transfection with the CA-IX–specific or scrambled siRNA (1 μg for 72 hours), and shNotch-3 and control MCF-7 cells. Shown are Western blot analysis of Notch-3 and β-actin protein and cell death analysis and RT-PCR analysis of Notch-3 and CA-IX mRNA (n = 3). *P = 0.017, **P = 0.008, ***P = 0.002, ANOVA. (B) Cell death analysis and RT-PCR analysis of Notch-3 and CA-IX mRNA in day 7 secondary T-MS exposed to 50 μM DFX for 48 hours in the presence or absence of anti–IL-6 (1.5 μg/ml for 48 hours) or anti-N3 (1.5 μg/ml for 48 hours) or transfected with CA-IX or scrambled siRNA (1 μg for 72 hours). n = 3 per group. #P = 0.022, ##P = 0.025, ###P = 0.044, ANOVA. (C) RT-PCR analysis and representative IHC analysis of CA-IX protein expression of breast carcinoma tissues from patients affected by basal-like or ductal breast carcinoma (see Table 2). Data are shown as CA-IX/β2μ mRNA ratio. ΧP = 0.002, Mann-Whitney test. β2μ was assessed as quantitative control for RT-PCR analysis. Scale bar: 100 μm.