抗血管新生之基因治療可增進原位肝腫瘤之免疫療法的療效

Anti-angiogenic Gene Therapies Enhance the Effects of Immunotherapy in Orthotopic Liver Tumors

王皓恬(Hao-Tien Wang)

指導教授 ： 黃麗華

國立臺灣大學/醫學院/微生物學研究所/博士(2012年)

https://doi.org/10.6342/NTU.2012.00019

摘要

免疫療法不只能有效地對抗腫瘤，其所產生的免疫記憶也能提供一個長時間的保護，避免腫瘤復發。然而，免疫療法所刺激活化的免疫細胞，往往因為腫瘤內不同機制的存在，無法正常發揮清除腫瘤的作用，影響治療效果。在本篇研究中，我們嘗試利用兩種不同的方式，來增強免疫療法(granulocyte macrophage colony-stimulating factor + interleukin-12)的療效。Calreticulin (CRT)是一個存在於內質網(endoplasmic reticulum)中的輔助蛋白(chaperon)，已被證實具有抗血管新生並抑制腫瘤生長的功能。在第一部份的實驗中，我們發現CRT 能增加腫瘤內皮細胞上黏附分子(adhesion molecule)的表現，這將有助於淋巴細胞與內皮細胞的結合，並增加淋巴細胞的穿透。因此，CRT能藉由增加淋巴細胞穿透至腫瘤的數量，有效提升免疫療法的抗腫瘤功效。另一方面，我們也嘗試著將免疫療法與endostatin (ED)和pigment epithelium-derived factor (PEDF)作結合。我們發現，相較於治療小腫瘤，免疫療法在治療大腫瘤時的療效會明顯減弱許多，而ED及PEDF的參與，將能增加對大腫瘤的抑制效果。進一步藉由觀察治療後不同時間點腫瘤內的變化，我們發現 ED 與 PEDF 可降低大腫瘤中的抑制免疫反應，使免疫療法在其中更易發揮治療效果。因此，縱使參與的機制不盡相同，我們所使用的兩種抗血管新生治療法，都能幫助經由免疫療法所刺激的免疫細胞，更有效率地在腫瘤處發揮其毒殺的功能，也因此，提升了免疫療法的治療效果。

關鍵字

抗血管新生 ； 基因治療 ； 免疫療法

並列摘要

Immunotherapy is an approach to systemically eradicate tumors, and the immunological memory established further provides long-term protection from cancer recurrence. However, the tumor-specific effector cells elicited by immunotherapy are usually inhibited by multiple mechanisms existing in the tumor microenvironment, thus greatly reducing the therapeutic efficacy. Here, we have attempted to improve immunotherapy (granulocyte macrophage colony-stimulating factor + interleukin-12) using various approaches. Calreticulin (CRT), a chaperon residing in the endoplasmic reticulum, has been shown to exert anti-angiogenic activity and inhibit tumor growth. In the first part of this study, we demonstrated a novel role for CRT, which can up-regulate the expression of adhesion molecules on tumor endothelial cells, resulting in enhanced lymphocyte-endothelial cell interactions and subsequent lymphocyte infiltration. Thus, combining CRT with immunotherapy would improve the anti-tumor effects of immunotherapy by markedly increasing the levels of tumor-infiltrating lymphocytes. We also examined the effect of combining immunotherapy with endostatin (ED) and pigment epithelium-derived factor (PEDF). While immunotherapy alone was much less effective in treating large tumors than in treating small tumors, ED and PEDF helped to improve the anti-tumor effect of immunotherapy. Observations from the dynamic changes in the tumor microenvironment revealed that ED + PEDF can alleviate immunosuppression, which might be related to reduce VEGF levels, making the tumors more vulnerable to immunotherapy. Therefore, although these two approaches mediate different mechanisms, both of the anti-angiogenic therapies can promote the function of immunotherapy-stimulated effector cells within the tumor region and thus improve the immunotherapeutic effects.

並列關鍵字

anti-angiogenic therapy ； gene therapy ； immunotherapy

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