2012-01-012024-05-14https://scholars.lib.ntu.edu.tw/handle/123456789/658972摘要：類胰島素生長因子﹝IGF﹞訊息傳導路徑已被證實對於包括肝細胞癌在內的多種癌症的發生以及藥物治療抗藥性的調控扮演重要的角色。過去研究指出抑制肝癌細胞IGF訊息傳導路徑可以引發細胞凋亡以及減低肝癌細胞對化療藥物之抗藥性。我們的研究結果顯示合併IGF訊息傳導路徑抑制劑 NVP-AEW541 (Novartis)與其他標靶治療藥物﹝例如sunitinib或erlotinib﹞可以增加肝癌細胞凋亡，可望改善肝癌藥物治療的效果﹝Eur J Cancer 2010; 8 (suppl): 99 (abstr #309)﹞。我們進一步在HCC細胞株以及人體臍帶血管內皮細胞﹝HUVEC﹞中測試這種協同增強﹝synergistic﹞作用的下游作用機轉。我們發現在IGF刺激下肝癌細胞及HUVEC 之IGF接受體以及其下游之AKT訊息傳導均會顯著活化。IGF刺激可以增強Hep3B細胞對sunitinib及erlotinib的抗藥性但是對sorafenib則無顯著影響。另一方面，IGF刺激則可增加HUVEC對sunitinib及sorafenib之抗藥性。NVP-AEW541與sunitinib及erlotinib對於引發肝癌細胞凋亡有協同增強效果，但與sorafenib則無。此一協同增強效果也經由活體HCC實驗模式證實。這種協同增強的效果與NVP-AEW541對於肝癌細胞中IGFR與AKT活性的影響無關。我們同時發現細胞中Chk2激酶﹝與細胞對於DNA受損反應之調控有關﹞的活化與NVP-AEW541及sunitinib 之協同增強效果有關：抑制Chk2激酶活化可部分消除此一協同增強效果。我們的結果顯示： 腫瘤微環境中之IGF可能增加肝癌細胞對於標靶治療藥物之抗藥性。IGF訊息傳導路徑的調控對於肝癌細胞凋亡的影響，可能與不同分子靶向藥物的特異性有關。Chk2激酶活化可能是調控IGF訊息傳導路徑抑制劑與其他分子靶向藥物之抗癌作用的重要機轉之一﹝2011 European Multidisciplinary Cancer Congress, abstr#1112﹞。在2012年我們將探討如何應用「垂直阻斷」﹝vertical blockade﹞的觀念，也就是在同一訊息傳遞路徑給予連續不同的抑制劑進一步增加藥物的抗癌效果。我們將測試合併IGFR抑制劑以及PI3K/AKT/mTOR訊息傳遞抑制劑的處方，找到最有效的組合以及其生物有效劑量﹝biologically effective doses﹞。將同時用體外及活體肝細胞癌試驗模式，探討這些藥物組合的作用機轉及可用來預測療效的生物指標。<br> Abstract: Insulin-like growth factor (IGF) signaling pathway has been demonstrated an important regulatory mechanism of tumorigenesis and drug resistance in many cancers. Previous studies have shown that inhibition of IGF signaling may induce apoptosis and reverse resistance to cytotoxic agents in HCC cells. Our previous studies suggested that combination of the IGFR inhibitor NVP-AEW541 (Novartis) with other molecular targeted agents, such as sunitinib or erlotinib, can enhance induction of apoptosis in HCC cells and may improve the therapeutic efficacy in HCC (Eur J Cancer 2010; 8 (suppl): 99 (abstr #309)). We further explore the possible downstream mediators of this anti-tumor synergy in HCC cells and human umbilical venous endothelial cells (HUVECs). We found that IGF can activate IGF receptor and downstream AKT signaling activities in all the HCC cells and HUVECs. Addition of IGF increased resistance of HUVECs to the multi-kinase inhibitors sorafenib and sunitinib. Resistance of HCC cells to sunitinib, but not sorafenib, was also increased with the addition of IGF. NVP-AEW541 significantly enhanced the apoptosis-inducing effects of sunitinib, but not sorafenib, of HCC cells both in vitro and in vivo. The synergistic effects between sunitinib and NVP-AEW541 were independent of inhibition of IGF receptor and AKT activities by NVP-AEW541. Activation of Chk2, which played important roles in regulation of DNA damage response, was found when NVP-AEW541 was combined with sunitinib but not with sorafenib. Knockdown of Chk2 expression by small interfering RNA partially abrogated the synergistic apoptosis-inducing effects of sunitinib and NVP-AEW541. Our data indicated that IGF in tumor microenvironment may increase resistance of HCC to molecular targeted therapy. The apoptosis-enhancing effects of IGF1 receptor inhibitors in HCC cells may be drug-specific, and Chk2 activation may be one important downstream mediator of the anti-cancer synergy between IGF1 receptor inhibitors and molecular targeted agents (2011 European Multidisciplinary Cancer Congress, abstr#1112). In the year 2012 we will test the concept of ‘vertical blockade, i.e., inhibition of sequential targets in the same signaling pathway to improve the anti-cancer efficacy. Combination of IGFR inhibitors and inhibitors of the PI3K/AKT/mTOR pathway will be explored to find out the optimal combinations and their biologically effective doses. In vitro and in vivo HCC models will be used to identify the mechanisms of action and predictive biomarkers of treatment efficacy.纇胰島素生長因子訊息傳導路徑標靶治療肝細胞癌Insulin-like growth factor (IGF)hepatocellular carcinoma, insulin-like growth factor signaling pathwayTargetedherapyhepatocellular carcinoma