結腸直腸癌腫瘤組織程式性死亡基因表現之探討

Study of expression of programmed cell death genes in colorectal cancer tissue

陳雅佩(Ya-Pei Chen)

指導教授 ： 周芬碧

中山醫學大學/醫學院/生化暨生物科技研究所/碩士(2010年)

https://doi.org/10.6834/CSMU.2010.00092

摘要

癌症的成因常是程式性死亡 (包括凋亡與自噬死亡) 的調控或 執行發生問題。程式性死亡需要許多基因的參與，而且兩種程式性死 亡途徑彼此間會互相影響，是非常複雜的過程。為了能更了解程式性 死亡在結腸直腸癌中所擔任的角色，我們使用定量PCR 陣列(RT-qPCR array) 的技術，針對由15 個結腸直腸癌的病人所取得的 15 對癌組織與配對的非癌組織，進行33 個參與在促進或抑制凋亡與 自噬死亡途徑以及生長的相關基因其mRNA 的定量分析，並以GAPDH 作為參考基因。癌組織中GAPDH mRNA 的濃度明顯高於非癌組織，平均增加4.01 倍。33 個基因中大部份基因的mRNA 含量在癌組織中亦是比較多。可是當使用GAPDH 進行校正後，癌組織中apoptosis 及autophagy的基因，除了DRAM，相對於非癌組織，皆有被顯著或非顯著的向下調節的現象。相關性分析則顯示大部分參與在同一程式性死亡途徑的基因的表現量，不論是在癌組織或非癌組織，彼此之間的關連性非常高，而且在癌組織中TNFR (apoptosis) 與Akt(autophagy) 與其他基因的相關性顯著增加。在相關性的分析上， 我們也發現， angiogenesis 的基因以及兩個程式性死亡路徑的相關基因，在非癌組織的相關性都較癌組織還要高。而這些angiogenesis 的基因在癌組織的表現是有利於抑制細胞走向apoptosis。結果顯示，GAPDH 基因表現的程度可能是癌細胞較高代謝狀態的一種反應，而程式性死亡在癌細胞的調控應以相對值來解釋，而非以絕對值來看。所以腫瘤組織中程式性死亡的相對性抑制現象，可能有助於癌細胞的生存。而這其中由TNFR 與Akt 所傳遞的訊息，可能參與癌化過程中對程式性死亡的調控。我們的研究對於兩種程式性死亡提供新的資訊，將有助於癌症的研究，尤其是結腸直腸癌。

關鍵字

結腸直腸癌 ； 程式性死亡 ； 定量PCR 陣列基因表現

並列摘要

Cancer is often caused by disturbance in the regulation and/or execution of programmed cell death (PCD including apoptosis and autophagy) which is a complex process involving many genes and interplay between different pathways. In order to understand further the pathological roles of PCD in colorectal cancer, we used RT-qPCR array
technique to quantitatively analyze the mRNA levels of 33
apoptosis ,autophagy and angiogenesis related genes involved in pro- and anti-action of the pathways in 15 paired (tumor and non-cancerous parts)colorectal samples using GAPDH as the reference gene.In tumor tissue GAPDH mRNA content was significantly higher than that of the paired non-cancerous part with an average increased fold
of 4.01. The absolute mRNA levels for most of the 33 genes were higher in the tumor tissue also. After normalization with GAPDH Ct, the expressions of apoptosis and autophagy the related genes, except DRAM, were down-regulated in the tumor tissues statistical significantly or non-significantly. Correlation analysis revealed that the expression of most of the genes involved in the same pathway was closely related to each other in both tumor tissues and non-cancerous tissues, and that the
correlation of TNFR (in apoptosis) and Akt (in autophagy) to other genes in the same pathway was increased in tumor tissues. The correlations of the levels between angiogenesis factors and the genes of these two PCDs
were expressions of angiogenesis factors in tumor tissues are in favor of inhibiting apoptosis. Our results indicated that the level of GAPDH expression might reflect the metabolic state of cancer cells, and the regulation of PCDs in cancerous cells might have to be explained as a relative phenomenon in stead of an absolute value. The relative suppression of PCDs in tumor tissue is supposed to be in favor of cancer cell survival. Signals conducting through TNFR and Akt might contribute to the modulation of PCDs during cancerous process. Our findings provide new evidences
concerning both types of PCD that are informative to cancer research, especially in colorectal cancer.

並列關鍵字

colorectal cancer ； programmed cell death ； RT-qPCR ； gene expression

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