Bruns Christiane J, Koehl Gudrun E, Guba Markus, Yezhelyev Maksim, Steinbauer Markus, Seeliger Hendrik, Schwend Astrid, Hoehn Anna, Jauch Karl-Walter, Geissler Edward K
Department of Surgery, University of Regensburg, Regensburg, Germany.
Clin Cancer Res. 2004 Mar 15;10(6):2109-19. doi: 10.1158/1078-0432.ccr-03-0502.
Despite current chemotherapies, pancreatic cancer remains an uncontrollable, rapidly progressive disease. Here, we tested an approach combining a recently described antiangiogenic drug, rapamycin, with standard gemcitabine cytotoxic therapy on human pancreatic tumor growth.
Tumor growth was assessed in rapamycin and gemcitabine-treated nude mice orthotopically injected with metastatic L3.6pl human pancreatic cancer cells. H&E staining was performed on tumors, along with Ki67 staining for cell proliferation and immunohistochemical terminal deoxynucleotidyl transferase-mediated nick end labeling and CD31 analysis. Rapamycin-treated tumor vessels were also directly examined in dorsal skin-fold chambers for blood flow after thrombosis induction. Cell death in human umbilical vein endothelial cells was assessed by flow cytometry after annexin-V staining.
Rapamycin therapy alone inhibited tumor growth and metastasis more than gemcitabine, with remarkable long-term tumor control when the drugs were combined. Mechanistically, H&E analysis revealed tumor vessel endothelium damage and thrombosis with rapamycin treatment. Indeed, dorsal skin-fold chamber analysis of rapamycin-treated tumors showed an increased susceptibility of tumor-specific vessels to thrombosis. Furthermore, terminal deoxynucleotidyl transferase-mediated nick end labeling/CD31 double staining of orthotopic tumors demonstrated apoptotic endothelial cells with rapamycin treatment, which also occurred with human umbilical vein endothelial cells in vitro. In contrast, gemcitabine was not antiangiogenic and, despite its known cytotoxicity, did not reduce proliferation in orthotopic tumors; nevertheless, rapamycin did reduce tumor proliferation.
Our data suggest a novel mechanism whereby rapamycin targets pancreatic tumor endothelium for destruction and thrombosis. We propose that rapamycin-based vascular targeting not only reduces tumor vascularization, it decreases the number of proliferating tumor cells to be destroyed by gemcitabine, thus introducing a new, clinically feasible strategy against pancreatic cancer.
尽管有目前的化疗方法，胰腺癌仍然是一种无法控制、进展迅速的疾病。在此，我们测试了一种将最近描述的抗血管生成药物雷帕霉素与标准吉西他滨细胞毒性疗法相结合的方法对人胰腺肿瘤生长的影响。
在原位注射转移性L3.6pl人胰腺癌细胞的裸鼠中评估雷帕霉素和吉西他滨治疗后的肿瘤生长情况。对肿瘤进行苏木精-伊红（H&E）染色，同时进行Ki67染色以检测细胞增殖，并进行免疫组织化学末端脱氧核苷酸转移酶介导的缺口末端标记及CD31分析。在诱导血栓形成后，还通过背部皮肤褶箱直接检查雷帕霉素治疗的肿瘤血管的血流情况。用膜联蛋白-V染色后通过流式细胞术评估人脐静脉内皮细胞的细胞死亡情况。
单独使用雷帕霉素治疗比吉西他滨更能抑制肿瘤生长和转移，联合使用这两种药物时能实现显著的长期肿瘤控制。从机制上讲，H&E分析显示雷帕霉素治疗可导致肿瘤血管内皮损伤和血栓形成。实际上，对雷帕霉素治疗的肿瘤进行背部皮肤褶箱分析表明，肿瘤特异性血管对血栓形成的敏感性增加。此外，原位肿瘤的末端脱氧核苷酸转移酶介导的缺口末端标记/CD31双重染色显示雷帕霉素治疗后内皮细胞凋亡，体外人脐静脉内皮细胞也出现这种情况。相比之下，吉西他滨不具有抗血管生成作用，尽管其具有已知的细胞毒性，但并未降低原位肿瘤的增殖；然而，雷帕霉素确实降低了肿瘤增殖。
我们的数据提示了一种新机制，即雷帕霉素靶向破坏胰腺肿瘤内皮并导致血栓形成。我们提出基于雷帕霉素的血管靶向不仅可减少肿瘤血管生成，还能减少吉西他滨要破坏的增殖肿瘤细胞数量，从而引入一种针对胰腺癌的新的临床可行策略。
