Phenotypic switch in blood: effects of pro-inflammatory cytokines on breast cancer cell aggregation and adhesion.
Hematogeneous metastasis can occur via a cascade of circulating tumor cell adhesion events to the endothelial lining of the vasculature, i.e. the metastatic cascade. Interestingly, the pro-inflammatory cytokines IL-6 and TNF-α, which play an important role in potentiating the inflammatory cascade, are significantly elevated in metastatic breast cancer (BCa) patients. Despite their high metastatic potential, human breast carcinoma cells MDA-MB-231 lack interactions with E-selectin functionalized surfaces under physiological shear stresses. We hypothesized that human plasma, 3-D tumor spheroid culture, and cytokine-supplemented culture media could induce a phenotypic switch that allows BCa cells to interact with E-selectin coated surfaces under physiological flow. Flow cytometry, immunofluorescence imaging, and flow-based cell adhesion assay were utilized to investigate the phenotypic changes of MDA-MB-231 cells with various treatments. Our results indicate that plasma, IL-6, and TNF-α promote breast cancer cell growth as aggregates and induce adhesive recruitment of BCa cells on E-selectin coated surfaces under flow. 3-D tumor spheroid culture exhibits the most significant increases in the interactions between BCa and E-selectin coated surfaces by upregulating CD44V4 and sLe(x) expression. Furthermore, we show that IL-6 and TNF-α concentrations in blood may regulate the recruitment of BCa cells to the inflamed endothelium. Finally, we propose a mechanism that could explain the invasiveness of 'triple-negative' breast cancer cell line MDA-MB-231 via a positive feedback loop of IL-6 secretion and maintenance. Taken together, our results suggest that therapeutic approaches targeting cytokine receptors and adhesion molecules on cancer cells may potentially reduce metastatic load and improve current cancer treatments.
Department of Biomedical Engineering, Cornell University, Ithaca, New York, United States of America.
Yue
Y
Geng
Siddarth
S
Chandrasekaran
Jong-Wei
JW
Hsu
Mishka
M
Gidwani
Andrew D
AD
Hughes
Michael R
MR
King
D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology; D002448:Cell Adhesion / Q000187:drug effects; D002449:Cell Aggregation / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D016207:Cytokines / Q000097:blood / Q000494:pharmacology*; D019040:E-Selectin / Q000378:metabolism; D004727:Endothelium / Q000187:drug effects / Q000378:metabolism; D005260:Female; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D018836:Inflammation Mediators / Q000097:blood / Q000494:pharmacology*; D015850:Interleukin-6 / Q000097:blood / Q000494:pharmacology; D008687:Metformin / Q000494:pharmacology; D009362:Neoplasm Metastasis; D009360:Neoplastic Cells, Circulating / Q000187:drug effects* / Q000378:metabolism*; D009844:Oligosaccharides / Q000378:metabolism; D010641:Phenotype; D000080506:Sialyl Lewis X Antigen; D018874:Spheroids, Cellular; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000097:blood / Q000494:pharmacology
D000893:Anti-Inflammatory Agents; D016207:Cytokines; D019040:E-Selectin; D018960:Hyaluronan Receptors; D018836:Inflammation Mediators; D015850:Interleukin-6; D009844:Oligosaccharides; D000080506:Sialyl Lewis X Antigen; D014409:Tumor Necrosis Factor-alpha; D008687:Metformin