- 學位論文
異硫氰酸酯類化合物抑制人類非小細胞肺癌失巢凋亡抗性
Dietary isothiocyanates reduce anoikis resistance of non-small cell human lung cancer cells
摘要
當細胞失去細胞基質或轉移到一個不適合的環境，會發生凋亡現象，這個過程稱之為失巢凋亡。失巢凋亡在癌症轉移扮演著重要角色。非小細胞肺癌細胞具有失巢凋亡抗性，有助於促使癌細胞轉移到其他器官。異硫氰酸酯 (isothiocyanates, ITCs) 存在於十字花科的植物如花椰菜、甘藍菜等。先前的研究指出ITCs具有預防癌症的功效，如肺癌、食道癌、乳癌、肝癌及結腸癌。Sulforaphane (SFN)、benzyl isothiocyanate (BITC) 及phenethyl isothiocyanate (PEITC)，是最常被研究之ITCs。本篇研究之主要目的為探討ITCs是否能抑制非小細胞肺癌失巢凋亡之抗性。將人類非小細胞肺癌A549及CL1-5細胞培養於經過特殊處理培養皿中使其成為懸浮狀。可以發現ITCs抑制懸浮培養之肺癌細胞生存率的作用比貼附培養之細胞強。此外ITCs也可以抑制懸浮細胞非錨定依賴性生長及球體形成。SFN造成癌細胞DNA特定型式斷裂以及caspase-3活化和PAPR裂解，證實可使懸浮肺癌細胞產生凋亡。在機轉探討方面，SFN抑制FAK活化以及抑制14-3-3ζ訊號傳遞路徑表現，如抗凋亡蛋白以及增加促凋亡蛋白。因上述結果顯示ITCs可以恢復非小細胞肺癌失巢凋亡的敏感性，對具有轉移性肺癌可能具有治療的潛力。
並列摘要
ells rapidly undergo apoptosis when relocate to an inadequate environment or loss of cell-matrix adhesion, in a process termed anoikis. Anoikis plays a vital role in the regulation of cancer metastasis which can inhibit tumor growth. In non-small cell lung cancers (NSCLCs), anoikis-resistant capability is the key step that enables cancer cells to succeed in their colonization at the secondary site. Isothiocyanates (ITCs) are natural compounds present in cruciferous vegetables (Brassicaceae) like broccoli, cabbage, and cauliflower. Previous studies showed that ITCs exhibit a protective effect against various types of cancer such as lung cancer, esophagitis, breast cancer, hepatocellular carcinoma, and colon cancer. Sulforaphane (SFN), benzyl isothiocyanate (BITC), and phenethyl isothiocyanate (PEITC) are the most well-known ITCs in cancers studies. For investigating whether ITCs reduce anoikis resistance in NSCLCs, human lung cancer A549 and CL1-5 cells were cultured in specially treated ultra-low culture dishes and treated with ITCs for 72 hours. ITCs inhibited cell viability in suspending A549 and CL1-5 cells, but had a less effect on the monolayer growth of adherent cells by using MTS assay. In addition, the inhibition of anchorage-independent growth by ITCs was observed by using sphere formation assay. SFN induced apoptosis of suspending A549 and CL1-5 cells which was identified by formation of DNA ladder, activation of casepase-3 and cleavage of PARP. Investigating the action of mechanism of SFN revealed that SFN inhibited FAK phosphorylation, reduced 14-3-3ζ and anti-apoptotic Bcl-2 proteins, as well as increased pro-apoptotic proteins. Taken together, our results indicate that ITCs can restore the sensitivity of NSCLCs to anoikis, and suggest a potential benefit of ITCs for treatment of metastatic lung cancer.