Investigation of oral carcinogenesis biomarkers by SR-FTIR and FTIR

• Main Authors: Li-Fang Chiu, 邱莉芳
• Other Authors: Yao-Chang Lee
• Format: Others
• Language: en_US
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/38033075532374541985

碩士 === 國立成功大學 === 口腔醫學研究所 === 97 === Oral cancer is the fourth leading cause of cancer death in Taiwanese male population. Early detection and staging of oral cancer and precancer lesions provide valuable information for the development of more effective preventive and therapeutic strategies of this malignant disease. Infrared absorption spectroscopy has been developed to identify the optical signature of specific chemical bonds. Fourier transform Infrared microspectroscopy using synchrotron radiation as the light source provides unsurpassed spatial and spectral resolution for the profiling of biochemical events occurred during disease progression. The present study aimed to analyze biochemical spectral changes accompanying carcinogenesis progression in cultured cells by employing SR-FTIR and FTIR to explore their potential clinical applications. We used primary cultured normal oral keratinocyte (hNOK), oral dysplasia precancer line (DOK), primary oral cancer line (SCC-15, OEC-M1, OC-2) and metastatic oral cancer line (HSC-3) as progression of oral cancer models. For each type of oral cells, there were recorded for their nuclear and cytoplasmic FT-IR spectrum in the spectral range between 3600 and 900 cm-1. Following the analogy, we discovered the average profile of absorbance at nucleus and cytoplasm during oral carcinogenesis progression states showed distinct spectra. Moreover, Linear Discriminant Analysis (LDA) for classification and dimensionality reduction was applied to cluster and rank the unique spectral features that discriminate normal cells from pre-cancer and cancer cells. The results indicate segregated tolerance region for hNOK from other cancer cells in lipid region (3000－2800 cm-1) and amide region (1760－1480 cm-1). In the bands of amide region (3600－3000 cm-1), it was a blue shift in dysplasia cell respectively, suggest there were potential value as precancer markers for diagnosis. In addition, there were distinct alterations in specific absorbed spectra of hNOK compared with precancer and other cancer cells in the spectral region 3000－2800 cm-1. The spectral region was assigned to anti-symmetric and symmetric vibration of CH functional group contributed mainly from lipid and protein of cells. We removed the major composition of lipid in cells to detected spectral signal. The overall absorbance had conversed from strong to weak after this process. We proposed that the level of lipid could be utilized to differentiate normal cells from cancer cells. Therefore, we employed organic waxes being different polarity, which are structurally similar to lipid structure of cell membrane to perform the physisorption for diagnosing oral cavity cancer. The infrared kinetic result of normal keratinocyte cells and cancer cells showed a strong capability of physisorption for paraffin and beeswax, respectively. These results support the potential for using SR-FTIR and FTIR as a label-free method for early screening of oral cancer and precancerous lesions to further discover the underlying contributing molecular events.