Characterization of Tumor Suppressor Genes Rb and p16 in Human Esophageal Carcinoma Primary Tissues and Cell Lines

• Main Authors: Xu, You-You, 許優優
• Other Authors: Li, Wan-Ruo
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/23099112545809113362

碩士 === 台北醫學院 === 細胞及分子生物研究所 === 85 === Esophageal Carcinoma is the tenth most common cancer in the Taiwanese population and the fifth most common cancer in the male population of Taiwan. Various genetic abnormalities have already been reported such as changes of tumor suppressor genes including p53, APC, MCC that genes are involved in esophageal carcinoma.The retinoblastoma gene product (pRB) is a nuclear phosphoprotein that is thought to play a key role in the negative regulation of cellular proliferation by modulating the activities of the transcriptional factors that control expression of S phase genes. D-type cyclins, in association with the cyclin-dependent kinases Cdk4 or Cdk6, promote progression through the G1 phase of the cell cycle by phosphorylating the pRB. The activities of Cdk4 and Cdk6 are constrained by inhibitors such as p16, the product of the p16 gene on human chromosome 9p21. The tumor suppressor gene p16(CDKN2/INK4A/MTS1) has been found to be deleted or mutated in a variety of human cancers. Thirteen human esophageal carcinoma primary tissue samples and five human esophageal carcinoma cell lines were analyzed for Rb gene alteration by single-strand conformational polymorphism (SSCP), DNA sequence analyses, and western blot assay. p16 gene alteration were detected by a method combining reverse transcription and nested polymerase chain reaction to detect different RNA transcripts of the p16 gene, associate with western blot assay to detect p16 protein expression, and polymerase chain reaction-methylation assay to detect the methylation status of genomic p16 gene in human esophageal carcinoma.The results showed that 2 of 13 esophageal carcinoma primary tissue samples and none of 5 esophageal carcinoma cell lines had altered Rb tumor suppressor gene; 3 of 10 primary tissue samples didn''t express pRb protein, including 1 primary tissue sample with altered Rb gene, but all of 5 cell lines express pRb protein. 8 of 13 primary tissues samples and all of 5 cell lines had altered p16 gene, 4 of 10 primary tissue samples and all of 5 cell lines fail to express p16 protein.Our result revealed that inactivation of the p16 tumor suppressor gene may play an important role in the development of esophageal carcinoma. But since the Rb tumor suppressor gene transcription factors binding sites alteration is not a frequent event in esophageal carcinoma, it will require more studies to understand Rb''s role in esophageal carcinoma.