Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/48451
標題: 厚朴酚誘導胃癌細胞凋亡暨抗腫瘤生長與GRP94蛋白裂解及內質網壓力生成機轉之探討
Cleavage of Glucose-Regulated Protein-94 by Honokiol Induces Endoplasmic Reticulum Stress-Mediated Human Gastric Cancer Cell Apoptosis and Tumor Growth in vitro and in vivo
作者: 許美鈴
關鍵字: 醫學技術;基礎研究;Honokiol, Calpain, GRP94, ER stress, Apoptosis.
摘要: 
胃癌位居全球癌症死亡的第二位。為了尋求更好的治療效果,探討胃癌細胞內的過度表達基因並進一步釐清其腫瘤生成機轉顯得格外重要。此外,由於目前使用之抗腫瘤藥物仍有許多的缺點及改進空間,所以積極發展或尋求新穎有效、作用在特定分子的抗腫瘤藥物,進而應用於臨床上,促使抗腫瘤療效更好、副作用反應更小將是理想的策略之一。我們已經著手研究人類胃癌細胞內的過度表達基因GRP94, 位居內質網內已知具有抗凋亡的特性。在許多腫瘤細胞株及腫瘤組織病理切片中皆可發現GRP94蛋白大量表達。然而對於其作用機轉、相關訊息傳遞之交互作用,以及將它列為腫瘤標的分子等卻很少有深入的探討。中藥厚樸萃取純化合物厚樸酚(Honokiol)在我們過去的研究中已知具抗氧化、抗發炎的作用。此外之外,也俱備抗血管增生、抗腫瘤特性,然而其分子作用機轉目前尚待研究。特別是影響與胃癌腫瘤相關的功能性基因更須進一步釐清與探討。本研究係針對胃癌腫瘤過量表達蛋白GRP94為標的分子蛋白,以厚樸酚(Honokiol)治療胃癌腫瘤。有鑒於腫瘤治療的重要性,我們認為這個研究模型值得深入探討。我們初步的研究發現:1. GRP94蛋白在胃癌腫瘤細胞株(MKN45, AGS, N87, SCM-1)及胃癌腫瘤組織切片皆有過量表達。2. 在試管內組織培養的環境中,厚樸酚具有促使細胞凋亡效應。3. 厚樸酚誘導胃癌腫瘤細胞株MKN45之GRP94蛋白減少,但GRP78蛋白並不受到影響。【計畫重點】基於現有的初步研究以及既往之報導發現,我們提出更進一步的研究促使厚樸酚對分子機制及腫瘤基因的調控有更深入的瞭解。我們擬以三年時間探討下列重點:1. 探討厚樸酚誘導胃癌腫瘤細胞株(MKN45, AGS, N87, SCM-1)細胞凋亡效應及促使GRP94 蛋白降解之機轉。2. 釐清厚樸酚是否影響細胞膜表面之酪胺酸激.磷酸化之活性或是作用於酪胺酸激.蛋白質本身之表現。3. 分析厚樸酚是否誘導內質網壓力之生成。4. 以動物模式分析厚樸酚是否具有對抗腫瘤生長、增加存活率、降低或降解GRP94 蛋白之表達及可能之藥物毒理之意義。我們的研究將打開更多的視野,暸解人類胃癌細胞GRP94 蛋白之調控機制,進而應用於臨床胃癌病人的治療,將有莫大的助益。

Gastric cancer was the second most common cause of death. To improve the therapeuticresults, the exploration of over-expression gene and elucidation of mechanism of tumorprogression are considered to be of great important. Current research in this area is driven bythe need to cover new agents in target specific molecule that will be more effective and havefewer side effects. We have initiated a study to search for cell signaling events involved inhuman gastric cancer genetic alterations.GRP94, is a 94 kDa calcium-binding glycoprotein. GRP94 is a chaperone proteinlocalized in the endoplasmic reticulum with antiapoptotic properties. In a variety of cancercell lines, rodent tumor models and human cancer biopsies, the level of GRP94 is elevated,correlatingwith increased tumorigenicity. Pathological conditions such as tumor growth andmalignancy correlate with cytoprotective protein GRP94 over-expression. Evidence showsthat GRP94 correlation with cancer progression and carcinogenesis. However, little is knowabout the mechanism and targeted therapy underlying their molecules action in gastric cancer.In the search for a more effective single or adjuvant therapy to treat gastric cancer, weinvestigated the effects of the Honokiol, an active component isolated from the herb 現Houpo現(Magnolia officinalis) traditional Chinese herbal medicines, on cell growth and apoptosis ofgastric cancer cells. Honokiol, an activated pure compound, was known to possess potentanti-oxidant, anti-inflammatory, anti-angiogenesis, anti-neoplastic properties. However, themolecular mechanism underlying the anticancer effect of Honokiol is poorly understood.Specifically, whether this pure compound affects the expression of cancer-related genes hasnot been defined. Thus, investigating changes in gene expression profiles, GRP94over-expression, as a result of herbal extract pure compound treatment may help define theunderlying mechanism of action and validate the efficacy of these anticancer reagents.Our preliminary data showed that:1. GRP94 overexpression in gastric cancer in vivo and in vitro.2. Honokiol activates apoptosis.3. Honokiol induces GRP94 protein reduction but not GRP78 protein in gastric cancer celllines.Encouraged by these findings, we decided to investigate whether Honkiol could also beuseful in an oncological context, exerting inhibits tumor growth, induces apoptosis andanti-tumor properties predictive of clinical translation. According to the aforementionedpreliminary data that we propose to study the effect of Honokiol-induced human gastriccancer apoptosis via regulates GRP94 degradation mechanism in in vitro assay and exhibitsantitumor activity in vivo focusing on 4 specific aims as below. Specific aims 1, 2 are to becompleted in the first year, and specific aim 3 in the two years, and specific aim 4 in the thirdyears.We propose a third years project to focus on:Specific Aims 1: Further to determine involves in Honokiol activates apoptosis and GRP94degradation signaling cascade and regulates mechanisms in human gastric cancer.Specific Aims 2: Further to verify Honokiol exerts biological activity in the target cellstyrosine-kinase expression or activity in vitro assay were carried out.Specific Aims 3: To identify whether Honokiol induces endoplasmic reticulum (ER) stress.Specific Aims 4: Further determined involves in Honokiol attenuates tumor GRP94over-expression, tumor burden and survival rate in nude mice.Our results should facilitate the understanding to the regulatory mechanism ofHonokiol-antitumor activity and provide the therapeutic possibility as a potentialchemotherapeutic agent.
URI: http://hdl.handle.net/11455/48451
其他識別: NSC96-2320-B005-007-MY3
Appears in Collections:生醫工程研究所

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