ANALYSIS OF DIFFERENTIAL GENE EXPRESSION IN NORMAL, CYST AND AMELOBLASTOMA CELLS

정상, 낭종 및 법랑아세포종 세포에서의 유전자 발현 차이 분석

Ameloblastoma is the most commonly occurring odontogenic tumor in oral cavity. Although most are benign epithelial neoplasm, they are generally considered to be locally aggressive and destructive, exhibiting a high rate of recurrence. The biological behavior of this neoplasm is a slowly growing, locally invasive tumor without metastasis, therefore malignant neoplasm, changed its histological appearance to carcinoma or showed distant metastasis, is only defined clinically. In this study, we identified the differentially expressed genes(DEGs) in stages under benign or malignant ameloblastoma compared with normal patient using ordered differential display(ODD) reverse transcription(RT)-PCR and $GeneFishing^{TM}$ technology. ODD RT-PCR is rather effective when the investigation of samples containing very small amounts of total RNA must be accomplished. ODD RT-PCR used the means of amplification with anchored T-primer and adaptor specific primer. bearing definite two bases at their 3' ends and so this method could display differential 3'-expressed sequence taqs(ESTs) patterns without using full-length cDNAs. Compared with standard differential display, ODD RT-PCR is more simple and have enough sensitivity to search for molecular markers by comparing gene expression profiles, However, this method required much effort and skill to perform. $GeneFishing^{TM}$ modified from DD-PCR is an improved method for detecting differentially expressed genes in two or more related samples. This two step RT-PCR method uses a constant reverse primer(anchor ACP-T) to prime the RT reaction and arbitrary primer pairs(annealing control primers, ACPs) during PCR. Because of high annealing specificity of ACPs than ODD RT-PCR, the application of $GeneFishing^{TM}$ to DEG discovery generates reproducible, authentic, and long(100bp to 2kb) PCR products that are detectable on agarose gels. Consequently, various DEGs observed differential expression levels on agarose gels were isolated from normal, benign, and malignant tissues using these methods. The expression patterns of the some isolated DEGs through ODD RT-PCR and $GeneFishing^{TM}$ were confirmed by Northern blot analysis and RT-PCR. The results showed that these identified DEGs were implicated in ameloblastoma neoplasm processes. Therefore, the identified DEGs will be further studied in order to be applied in candidate selection for marker as an early diagnosis during ameloblastoma neoplasm processes.

법랑아세포종은 1868년에 처음 보고된 이래 명칭, 발생기전, 분류 그리고 치료 방법 등에 관하여 수 많은 논란이 있어 왔는데 이는 법랑세포종이 양성종양임에도 불구하고 종양자체의 진행이 파괴적이고, 외과적 처치를 한 후에도 재발이 잘되며, 흔하지는 않지만 악성종양과 유사하게 전이를 보이는 등 독특한 특성을 지니고 있기 때문이다. 정상세포와 암 세포 간에 차이를 보이는 유전자 혹은 정상세포에서 변형이 일어날 때 특이적으로 발현하는 유전의 분리 및 분석하는 것은 암세포의 생성과정을 이해하는데 있어서 중요한 열쇠를 제공할 수 있다. 이에 본 연구는 RNA differential display 방법 중 재연성과 반복성이 개선된 Ordered differential display(ODD)RT-PCR과 보다 개선된 $GeneFishing^{TM}$기술을 이용하여 악성과 양성종양 사이의 유전자 발현의 차이를 조사하고, 특이 유전자의 profile을 확보하고자 하였다. $GeneFishing^{TM}$기술과 RT-PCR을 수행한 결과 nasopharyngeal carcinoma gene을 제외한 9개의 유전자는 악성에서 특이적으로 발현되는 것을 확인하였다. 따라서 $GeneFishing^{TM}$을 이용하면 각 시료간의 mRNA 상에서 발현차이를 보이는 DEG를 비교 분석하면 암관련 유전자, 항생제 태성 유전자, 그리고 분화 관련 유전자들에 대한 연구가 용이하게 수행할 수 있을 것으로 생각된다.