Variable E-Cadherin Expression in a MNU-Induced Colon Tumor Model in Rats Which Exposed with 50 Hz Frequency Sinusoidal Magnetic Field

Variable E-Cadherin Expression in a MNU-Induced Colon Tumor Model
in Rats Which Exposed with 50 Hz Frequency
Sinusoidal Magnetic Field

HANDAN TUNCEL, FUMIO SHIMAMOTO,¹ PENBE CAGATAY² and M. TUNAYA KALKAN

Biophysics Department, Istanbul University, Cerrahpasa Medical Faculty, Istanbul 34303, Turkey,
¹Department of Pathology, Hiroshima Prefectural Womens University, School of Health Sciences, Hiroshima 734-8558, and
²Biostatistics Department, Istanbul University, Cerrahpasa Medical Faculty, Istanbul 34303, Turkey

Inactivation of the E-cadherin system by multiple mechanisms, including both genetic and epigenetic events, plays a significant role in multistage carcinogenesis. We have investigated the effects of sinusoidal electromagnetic fields (SMF) on E-cadherin expression in an MNU (N-methyl-N-nitrosurea)-induced colon tumor model. Male wistar albino rats were used for the study. The rats were classified into four groups: I (MNU), II (SMF+MNU), III (SMF) and IV (control). After administered at MNU in 1st and 2nd groups, 2nd and 3rd groups were exposed to a sinusoidal magnetic field (SMF, 50 Hz, 5 mT) for 6 hours/day for 8 months. The expression of E-cadherin were examined in four groups of rat colon tissues by immunohistochemistry on paraffin sections. For immunohistochemical analysis, the labeled streptavidin biotin method was performed using a Vectastain Universal Quick Kit with microwave accentuation. Fisher's exact test was used for statistical analysis between proportions. Immunohistochemical studies of E-cadherin expression in this model demonstrated significant differences for cytoplasmic expression pattern. These results suggest that the electromagnetic fields result in significant alterations in cell adhesion mechanisms. This study has implications for understanding the role of fields in cell detachment in cancer metastasis. Further work is required to determine the relative effect of the magnetic fields on these phenomena.

Keywords —— E-cadherin; carcinogenesis; electromagnetic fields; immunohistochemistry

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Tohoku J. Exp. Med., 2002, 198, 245-249

Address for reprints: Handan Tuncel, Ph. D., Cirpici Mh. Yesil Yol F Sk. Yavuz apt. No: 33/4 Zeytinburnul, 34660, Istanbul, Turkey.

e-mail: handantun@superonline.com

This paper was presented at the 2nd International Workshop on Biological Effects of Electromagnetic Fields held on October 7-11, 2002, Aldemar Paradise Royal Mare Hotel, Rhodes, Greece.