利用cDNA microarray 分析急性白血病病患的基因表現

背景: 急性白血病包含許多不同亞型，表現出不同的形態特徵、細胞表面抗原、 細胞染色體異常，臨床表現、治療反應、與預後也有不同。以往我們對其分 子機轉所知甚少，近年來cDNA 微陣列及相關技術的研發，使得大量分析細 胞基因轉譯表現型變為可行。 研究目的： (1). 建立利用cDNA 微陣列研究急性白血病的模式。 (2). 建立急性白血病各不同亞型初診斷及復發時之基因轉譯表現型模式，以尋找 篩選出導致疾病惡化與抗藥性之候選基因。 研究方法： (1)選擇三組病患: 急性骨髓性白血病併 t(7;11)，急性骨髓性白血病併 inv(16)， 及急性淋巴性白血病併t(9;22)，並收集初診斷及復發時的骨髓細胞。 (2)萃取骨髓細胞RNA，並進行反轉錄在反轉錄過程中嵌入放射性同位素33P。 (3)將嵌入33P 的RNA 和cDNA 微陣列雜交後以PhospoImage 系統讀取並以 AtlasImage 系統分析 結果及討論： 在復發時過度表現的基因，多和細胞週期促進或細胞存活有關。例如：在急性骨 髓性白血病併inv(16)中之c-myc 和CDKN1A。其他過度表現的基因還包括某些 轉錄因子， 例如：在急性骨髓性白血病併t(7;11) 的basic-leucine zipper transcription factor MAFG 以及 signal transducing adaptor molecule (STAM)。但是 也有某些此類基因的表現在復發時被壓抑，例如：急性淋巴性白血病併t(9;22) 中的Cell cycle progression restoration protein 8 (CPR8) 以及elongation factor 1 alpha (EF1 alpha) 。並且我們發現在不同型白血病的復發中，可發現不同的基因 表現形式改變，表示它們形成復發及抗藥性的機轉並不相同。Background: Acute leukemia, a common hematological malignancy, is clinically divided into various subtypes according to morphology, immunophenotypes and cytogenetic changes, and various genetic and molecular abnormalities with significant prognostic implications could be found in many subtypes. However, because of the large-scale data and time-consuming laboratory works needed to illustrate the gene expression patterns, we still know little about the mechanisms of leukemogenesis, disease progression and development of drug resistance in the patients with acute leukemia. Aims: 1. As a pilot study to evaluate the efficacy of cDNA microarray in exploring the expression gene profiles in acute leukemia. 2. To explore the possible genes differentially expressed in the development of leukemic drug resistance. Methods: 1. Sample collection: Patients with inv(16) AML, t(7;11) AML and t(9;22) ALL diagnosed in NTUH is selected eligible for study 歐. 2. RNA extraction and RT will be performed, and the cDNAs were labeled with radioisotope 33P at the step of RT. 3. 33P-labeled cDNA probes will be hybridized with designed cDNA microarray. PhospoImage system will be used for reading signals, and AtlasImage system is used for data analysis. Results and discussion: we find that many over-expressed genes are related to cell cycle progression and cell survival enhancing such as c-myc and CDKN1A in AML with inv(16); some others belong to the family of transcription activation factors, such as basic-leucine zipper transcription factor MAFG and signal transducing adaptor molecule (STAM) in AML with t(7;11). However, this is not always true since several genes related to cell survival and cell cycles also are down-regulated during disease progression, such as Cell cycle progression restoration protein 8 (CPR8) and elongation factor 1 alpha (EF1 alpha) in ALL with t(9;22). Furthermore, different genes are up- or down-regulated in disease relapse in different kinds of acute leukemia. Different kinds of mechanism for drug resistance thus are proposed in various types of leukemia. However, final common results are obtained