Lipoxygenase mediates invasion of intrametastatic lymphatic vessels and propagates lymph node metastasis of human mammary carcinoma xenografts in mouse
Dontscho Kerjaschki, … , Dieter Steinhilber, Georg Krupitza
Dontscho Kerjaschki, … , Dieter Steinhilber, Georg Krupitza
Published April 11, 2011
Citation Information: J Clin Invest. 2011;121(5):2000-2012. https://doi.org/10.1172/JCI44751.
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Research Article Oncology

Lipoxygenase mediates invasion of intrametastatic lymphatic vessels and propagates lymph node metastasis of human mammary carcinoma xenografts in mouse

Abstract

In individuals with mammary carcinoma, the most relevant prognostic predictor of distant organ metastasis and clinical outcome is the status of axillary lymph node metastasis. Metastases form initially in axillary sentinel lymph nodes and progress via connecting lymphatic vessels into postsentinel lymph nodes. However, the mechanisms of consecutive lymph node colonization are unknown. Through the analysis of human mammary carcinomas and their matching axillary lymph nodes, we show here that intrametastatic lymphatic vessels and bulk tumor cell invasion into these vessels highly correlate with formation of postsentinel metastasis. In an in vitro model of tumor bulk invasion, human mammary carcinoma cells caused circular defects in lymphatic endothelial monolayers. These circular defects were highly reminiscent of defects of the lymphovascular walls at sites of tumor invasion in vivo and were primarily generated by the tumor-derived arachidonic acid metabolite 12S-HETE following 15-lipoxygenase-1 (ALOX15) catalysis. Accordingly, pharmacological inhibition and shRNA knockdown of ALOX15 each repressed formation of circular defects in vitro. Importantly, ALOX15 knockdown antagonized formation of lymph node metastasis in xenografted tumors. Furthermore, expression of lipoxygenase in human sentinel lymph node metastases correlated inversely with metastasis-free survival. These results provide evidence that lipoxygenase serves as a mediator of tumor cell invasion into lymphatic vessels and formation of lymph node metastasis in ductal mammary carcinomas.

Authors

Dontscho Kerjaschki, Zsuzsanna Bago-Horvath, Margaretha Rudas, Veronika Sexl, Christine Schneckenleithner, Susanne Wolbank, Gregor Bartel, Sigurd Krieger, Romana Kalt, Brigitte Hantusch, Thomas Keller, Katalin Nagy-Bojarszky, Nicole Huttary, Ingrid Raab, Karin Lackner, Katharina Krautgasser, Helga Schachner, Klaus Kaserer, Sandra Rezar, Sybille Madlener, Caroline Vonach, Agnes Davidovits, Hitonari Nosaka, Monika Hämmerle, Katharina Viola, Helmut Dolznig, Martin Schreiber, Alexander Nader, Wolfgang Mikulits, Michael Gnant, Satoshi Hirakawa, Michael Detmar, Kari Alitalo, Sebastian Nijman, Felix Offner, Thorsten J. Maier, Dieter Steinhilber, Georg Krupitza

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Figure 3

12(S)-HETE causes CCIDs in lymphatic endothelial cell monolayers.

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12(S)-HETE causes CCIDs in lymphatic endothelial cell monolayers. (A) CC...
(A) CCID area in lymphatic endothelial cell monolayers induced by HLF cell spheroids that were presoaked with synthetic 12(S)-HETE (n = 11), 15(S)-HETE (n = 12), or solvent alone (control; n = 21). 12(S)-HETE induced approximately 20 times larger CCIDs than controls (*P < 0.0001) after 4 hours of coincubation. (B) Antibody against 12(S)-HETE reduces the CCID area by approximately 50% (*P = 0.0020). (C) The ALOX inhibitor baicalein, a traditional Asian anti-cancer drug, reduces CCID area in a dose-dependent fashion, with the highest dose of 500 μM (n = 11) causing reduction to 38% (*P < 0.0001) of controls (n = 20). (D) Time-course incubation over 4 hours with 100 μM baicalein in the media results in approximately 90% reduction of CCID size in the first 2 hours and a gradual increase in CCID formation to more than 50% after 4 hours. (E) Spheroids made of the mammary carcinoma cell lines HCC1419, HCC1443, and MDA-MB231 form spheroids that induce CCIDs in lymphatic monolayers, but only HCC1419 cell–mediated CCID formation is sensitive to 100 μM baicalein (inhibition of 78.2%; *P = 0.0008). Similarly, spheroids formed from colorectal carcinoma cell lines LS174CoCa, HT29, and HTC116 form CCIDs, but only LS174CoCa are baicalein sensitive (inhibition of 53.3%; **P = 0.0168). A melanoma (CRL1675Mel) and a pancreatic carcinoma cell line (PANC1) formed CCIDs in monolayers of lymphatic endothelial cells, but were insensitive (i.e., statistically not significant) to baicalein. All data are presented as mean ± SEM.