BACKGROUND: Fourier-transform infrared spectroscopy (FT-IR) is a powerful tool for study of the secondary conformation of intact protein in biological tissues and for diagnosis of disease states. The purpose of this study is to utilize FT-IR as a diagnostic tool to estimate the secondary structure of amide I in normal and cancer tissue of human colon. METHODS: Pairs of tissue samples from colon cancer and histologically normal mucosa tissue 5-10 cm from the tumor were obtained from a patient who underwent partial colectomy. In the present study we investigated the changes in the secondary structure of amide I of normal and malignant human colon tissue using FT-IR microspectroscopy with attenuated total reflectance. Secondary-derivative analysis relative to the original and curve-fitting analysis infrared spectra were also carried out. RESULTS: The conformational changes of the secondary structure of protein in normal and cancerous human colon tissue were (1) the composition of alpha-helixes increased in human cancerous colon tissue (15.30%) compared to normal colon tissue (11.72%); (2) beta-sheets which were 46.8% in healthy tissue decreased to 30.71% in cancer tissue; (3) beta-turns increased from 26.28% in normal tissue to 38.48% in cancer tissue; and (4) the composition of random coils was not significantly different between normal tissue (15.12%) and cancer tissue (15.51%). CONCLUSION: Our data demonstrate that protein in colon cancer displays abnormal FT-IR spectra. The conformational changes of the secondary structure of this protein in terms of alpha-helixes, beta-sheets and beta-turns were observed in normal and cancerous tissue from the same individual were compared.
BACKGROUND: Fourier-transform infrared spectroscopy (FT-IR) is a powerful tool for study of the secondary conformation of intact protein in biological tissues and for diagnosis of disease states. The purpose of this study is to utilize FT-IR as a diagnostic tool to estimate the secondary structure of amide I in normal and cancer tissue of human colon. METHODS: Pairs of tissue samples from colon cancer and histologically normal mucosa tissue 5-10 cm from the tumor were obtained from a patient who underwent partial colectomy. In the present study we investigated the changes in the secondary structure of amide I of normal and malignant human colon tissue using FT-IR microspectroscopy with attenuated total reflectance. Secondary-derivative analysis relative to the original and curve-fitting analysis infrared spectra were also carried out. RESULTS: The conformational changes of the secondary structure of protein in normal and canceroushuman colon tissue were (1) the composition of alpha-helixes increased in humancancerous colon tissue (15.30%) compared to normal colon tissue (11.72%); (2) beta-sheets which were 46.8% in healthy tissue decreased to 30.71% in cancer tissue; (3) beta-turns increased from 26.28% in normal tissue to 38.48% in cancer tissue; and (4) the composition of random coils was not significantly different between normal tissue (15.12%) and cancer tissue (15.51%). CONCLUSION: Our data demonstrate that protein in colon cancer displays abnormal FT-IR spectra. The conformational changes of the secondary structure of this protein in terms of alpha-helixes, beta-sheets and beta-turns were observed in normal and cancerous tissue from the same individual were compared.