TY - JOUR

T1 - TNF-α induced secretion of HMGB1 from non-immune canine mammary epithelial cells (MTH53A)

AU - Willenbrock, Saskia

AU - Braun, Olga

AU - Baumgart, Judith

AU - Lange, Sandra

AU - Junghanss, Christian

AU - Heisterkamp, Alexander

AU - Nolte, Ingo

AU - Bullerdiek, Jörn

AU - Murua Escobar, Hugo

N1 - Funding information: This work was funded by the German Research Foundation (DFG) within the SFB/TransRegio 37 (Micro- and Nanosystems in Medicine) and supported by the Research Cluster of Excellence “REBIRTH”.

PY - 2012/2

Y1 - 2012/2

N2 - Background: Mammary neoplasias are one of the most frequent and spontaneously occurring malignancies in dogs and humans. Due to the similar anatomy of the mammary gland in both species, the dog has become an important animal model for this cancer entity. In human breast carcinomas, the overexpression of a protein named high-mobility group box 1 (HMGB1) was reported. Cells of the immune system were described to release HMGB1 actively exerting cytokine function. Thereby it is involved in the immune system activation, tissue repair, and cell migration. Passive release of HMGB1 by necrotic cells at sites of tissue damage or in necrotic hypoxic regions of tumors induces cellular responses e.g. release of proinflammatory cytokines leading to elevated inflammatory response and neo-vascularization of necrotic tumor areas.Herein we investigated if a time-dependent stimulation with the separately applied proinflammatory cytokines TNF-α and IFN-γ can cause secretion of HMGB1 in a non-immune related HMGB1-non-secreting epithelial canine mammary cell line (MTH53A) derived from non-neoplastic tissue. Methods: The canine cell line was transfected with recombinant HMGB1 bicistronic expression vectors and stimulated after transfection with the respective cytokine independently for 6, 24 and 48. h. HMGB1 protein detection was performed by Western blot analysis and quantified a by enzyme-linked immunosorbent assay. Live cell laser scanning multiphoton microscopy of MTH53A cells expressing a HMGB1-GFP fusion protein was performed in order to examine, if secretion of HMGB1 under cytokine stimulating conditions is also visible by fluorescence imaging. Results: The observed HMGB1 release kinetics showed a clearly time-dependent manner with a peak release 24. h after TNF-α stimulation, while stimulation with IFN-γ had only small effects on the HMGB1 release. Multiphoton HMGB1 live cell microscopy showed diffuse cell membrane structure changes 29. h after cytokine-stimulation but no clear secretion of HMGB1-GFP after TNF-α stimulation was visible. Conclusion: Our results demonstrate that non-immune HMGB1-non-secreting cells of epithelial origin derived from mammary non-neoplastic tissue can be induced to release HMGB1 by single cytokine application. This indicates that tumor and surrounding tissue can be stimulated by tumor present inflammatory and necrotic cytokines to release HMGB1 acting as neo-vascularizing factor thus promoting tumor growth.

AB - Background: Mammary neoplasias are one of the most frequent and spontaneously occurring malignancies in dogs and humans. Due to the similar anatomy of the mammary gland in both species, the dog has become an important animal model for this cancer entity. In human breast carcinomas, the overexpression of a protein named high-mobility group box 1 (HMGB1) was reported. Cells of the immune system were described to release HMGB1 actively exerting cytokine function. Thereby it is involved in the immune system activation, tissue repair, and cell migration. Passive release of HMGB1 by necrotic cells at sites of tissue damage or in necrotic hypoxic regions of tumors induces cellular responses e.g. release of proinflammatory cytokines leading to elevated inflammatory response and neo-vascularization of necrotic tumor areas.Herein we investigated if a time-dependent stimulation with the separately applied proinflammatory cytokines TNF-α and IFN-γ can cause secretion of HMGB1 in a non-immune related HMGB1-non-secreting epithelial canine mammary cell line (MTH53A) derived from non-neoplastic tissue. Methods: The canine cell line was transfected with recombinant HMGB1 bicistronic expression vectors and stimulated after transfection with the respective cytokine independently for 6, 24 and 48. h. HMGB1 protein detection was performed by Western blot analysis and quantified a by enzyme-linked immunosorbent assay. Live cell laser scanning multiphoton microscopy of MTH53A cells expressing a HMGB1-GFP fusion protein was performed in order to examine, if secretion of HMGB1 under cytokine stimulating conditions is also visible by fluorescence imaging. Results: The observed HMGB1 release kinetics showed a clearly time-dependent manner with a peak release 24. h after TNF-α stimulation, while stimulation with IFN-γ had only small effects on the HMGB1 release. Multiphoton HMGB1 live cell microscopy showed diffuse cell membrane structure changes 29. h after cytokine-stimulation but no clear secretion of HMGB1-GFP after TNF-α stimulation was visible. Conclusion: Our results demonstrate that non-immune HMGB1-non-secreting cells of epithelial origin derived from mammary non-neoplastic tissue can be induced to release HMGB1 by single cytokine application. This indicates that tumor and surrounding tissue can be stimulated by tumor present inflammatory and necrotic cytokines to release HMGB1 acting as neo-vascularizing factor thus promoting tumor growth.

KW - Canis familiaris

KW - Cytokines

KW - HMGB1

KW - Secretion

KW - Tumor

UR - http://www.scopus.com/inward/record.url?scp=84855463690&partnerID=8YFLogxK

U2 - 10.1016/j.cyto.2011.11.011

DO - 10.1016/j.cyto.2011.11.011

M3 - Article

C2 - 22154216

AN - SCOPUS:84855463690

VL - 57

SP - 210

EP - 220

JO - Cytokine

JF - Cytokine

SN - 1043-4666

IS - 2

ER -