Tumor necrosis factor alpha stimulates invasion of Src-activated intestinal cells.
OBJECTIVE
Src activation is correlated with progression of colorectal cancer (CRC). CRCs accompanied by ulcerative colitis, chronic inflammation in the colon, often have elevated Src activity, and ulcerative colitis-related CRCs are more likely to become invasive, whereas Ras activation is rarely associated with this disease. The aim of this study was to investigate the effects of a proinflammatory cytokine, tumor necrosis factor alpha (TNF-alpha), on the invasive properties of epithelial cells constitutively expressing activated Ras or Src.


METHODS
A cell line derived from intestinal epithelia was transfected with a v-src- or v-H-ras-expressing vector. The effect of TNF-alpha on morphologic changes in colonies cultured in soft agar was determined. Src protein kinase activity, peroxide production, E-cadherin expression levels, and the phosphorylation status of beta-catenin and E-cadherin were determined. The invasive potential of these cells was determined by measuring cell motility and using an in vitro invasion assay.


RESULTS
TNF-alpha altered the colony morphology of src-, but not ras-expressing cells. TNF-alpha increased peroxide production, leading to Src protein expression as well as Src activity in src transfectants. Activation of Src by TNF-alpha led to reduced E-cadherin levels and enhanced invasion of src transfectants. Pyrrolidine dithiocarbamate and herbimycin A inhibited these effects.


CONCLUSIONS
These results indicate that Src kinase activation enhances the response of epithelial cells to TNF-alpha leading to increased invasion through mechanisms that involve production of reactive oxygen intermediates.
Kawai
Naoki
N
Graduate School of Medicine, Department of Internal Medicine and Therapeutics, Faculty of Medicine, Osaka University, Japan.
Tsuji
Shingo
S
Tsujii
Masahiko
M
Ito
Toshifumi
T
Yasumaru
Masakazu
M
Kakiuchi
Yoshimi
Y
Kimura
Arata
A
Komori
Masato
M
Sasaki
Yutaka
Y
Hayashi
Norio
N
Kawano
Sunao
S
Dubois
Raymond
R
Hori
Masatsugu
M
D000362:Agar; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology; D015820:Cadherins / Q000378:metabolism; D002461:Cell Line, Transformed; D002465:Cell Movement / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D007413:Intestinal Mucosa / Q000166:cytology; D009361:Neoplasm Invasiveness / Q000503:physiopathology; D015689:Oncogene Protein p21(ras) / Q000235:genetics / Q000378:metabolism; D015688:Oncogene Protein pp60(v-src) / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D019000:Phosphotyrosine / Q000378:metabolism; D011759:Pyrrolidines / Q000494:pharmacology; D051381:Rats; D013859:Thiocarbamates / Q000494:pharmacology; D015534:Trans-Activators; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014443:Tyrosine / Q000378:metabolism; D051176:beta Catenin
D000970:Antineoplastic Agents; D000975:Antioxidants; D015820:Cadherins; C495268:Ctnnb1 protein, rat; D003598:Cytoskeletal Proteins; D011759:Pyrrolidines; D013859:Thiocarbamates; D015534:Trans-Activators; D014409:Tumor Necrosis Factor-alpha; D051176:beta Catenin; D019000:Phosphotyrosine; C020972:pyrrolidine dithiocarbamic acid; D014443:Tyrosine; D000362:Agar; D006861:Hydrogen Peroxide; D015688:Oncogene Protein pp60(v-src); D015689:Oncogene Protein p21(ras)