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IL-4 and TNF-alpha induce changes in integrin expression and adhesive properties and decrease the lung-colonizing
F Herzberg1, M Schöning, M Schirner
1Department of Hematology and Oncology, University Medical Center Benjamin Franklin, Free University of Berlin, Germany. herzberg@fub46.zedat.fu-berlin.de.
Abstract:
The colon carcinoma cell line HT-29 was used to explore the potential of interleukin-4 (IL-4) and tumor necrosis factor alpha (TNF-alpha) to modify integrin expression and adhesive functions of tumor cells in vitro and to examine corresponding metastatic effects in vivo. Preincubation of HT-29 cells with 100 U/ml of IL-4 for 48 h downregulated the surface expression of the integrin subunits alpha 2, alpha 3, beta 1 and beta 4 after 48 h, whereas the alpha 1 subunit was upregulated. In contrast, 100 U/ml to TNF-alpha selectively upmodulated the expression of alpha v. Attachment to fibronectin of cells treated with IL-4 increased twofold (63.5% vs 32.4%). Adhesion to fibronectin (54.0% vs 32.4%) and vitronectin (37.9% vs 16.4%) was elevated in the case of TNF-alpha stimulation. Using an experimental metastasis model, HT-29 cells showed a significant reduction of their lung-colonizing potential in nude mice when preincubated with IL-4 for 48 h before intravenous injection. The decrease also observed for TNF-alpha-treated cells was less pronounced. The data indicate that the cytokines IL-4 and TNF-alpha can act as direct regulators of adhesive mechanisms of tumor cells bearing adequate receptors, thus influencing lung-colony formation.
Insights
Interleukin-4 (IL-4) and tumor necrosis factor alpha (TNF-alpha) alter colon cancer cell adhesion and integrin expression. These cytokines impact tumor cell metastasis, with IL-4 showing a more significant reduction in lung colonization.
Area of Science:
- Oncology
- Immunology
- Cell Biology
Background:
- Integrins are crucial for tumor cell adhesion and metastasis.
- Cytokines like IL-4 and TNF-alpha can modulate cellular functions.
- Understanding cytokine effects on tumor cell integrins is vital for cancer research.
Purpose of the Study:
- To investigate how IL-4 and TNF-alpha affect integrin expression in HT-29 colon carcinoma cells.
- To examine the impact of these cytokines on tumor cell adhesion to extracellular matrix proteins.
- To evaluate the in vivo metastatic potential of cytokine-treated tumor cells.
Main Methods:
- HT-29 colon carcinoma cells were treated with IL-4 or TNF-alpha.
- Integrin subunit expression was analyzed using flow cytometry.
- Cell adhesion assays were performed using fibronectin and vitronectin.
- An experimental metastasis model in nude mice was employed to assess lung colonization.
Main Results:
- IL-4 downregulated integrin subunits alpha 2, alpha 3, beta 1, and beta 4, while upregulating alpha 1.
- TNF-alpha selectively upregulated integrin subunit alpha v.
- Both cytokines enhanced tumor cell adhesion to fibronectin and vitronectin.
- IL-4 pre-treatment significantly reduced lung colonization in vivo, while TNF-alpha showed a less pronounced effect.
Conclusions:
- IL-4 and TNF-alpha directly regulate tumor cell integrin expression and adhesive properties.
- These cytokine-induced changes in adhesion influence the metastatic capacity of colon carcinoma cells.
- Targeting cytokine-integrin interactions may offer therapeutic strategies for reducing cancer metastasis.