粒细胞集落刺激因子对结直肠癌肿瘤生长及转移的作用与机制

Granulocyte-colony stimulating factor (G-CSF) is widely used in clinic on patients with colorectal cancer to overcome the chemotherapy and radiotherapy associated myelosuppression. However, recent studies have suggested that G-CSF may potentially promote cancer growth in patients with malignancy. Then, questions arise that whether it is safe to administrate G-CSF to patients with colorectal cancer? Will it promote the growth and spread of tumor? And how does it effect? Our previous work has indicated that the use of G-CSF might promote the release of cancer cells to peripheral blood while it mobilizes bone marrow hematopoietic stem/porogenitor cells. The present project was therefore designed to visualize the changes of circulating tumor cells (CTCs) before and after the administration of G-CSF with an aim to obtain the direct evidence of the prometastatic effects of G-CSF on colorectal cancer patients. Before the detection with a variety of molecular pathological techniques as real-time quantitative RT-PCR, immunofluorescence staining, and fluorescence in situ hybridization (FISH), we employ immunomagnetic separation technology to enrich the circulation tumor cells. Next, we investigate their biological characteristics, invasion and tumorigenesis ability by cell culture and mouse inoculation. Further, we construct a visualizing tumor metastasis model, on which we observe dynamically the effects of G-CSF on the growth and spread of colon cancer in vivo. We also investigate the role of G-CSFR and SDF-1/CXCR4 axis on the process of function, and the counteraction of G-CSFR neutralizing antibody and CXCR4 antagonist against tumor growth and metastasis, to explore the mechanisms of G-CSF effecting and the key point for adjustment.

粒细胞集落刺激因子(G-CSF)是临床上防治结直肠癌放化疗后骨髓抑制的常用药物，近年研究表明其可能会促进肿瘤生长，那么，G-CSF应用于结直肠癌患者是否安全？会否促进肿瘤生长或转移？其机制又如何？我们前期荧光定量RT-PCR研究提示，G-CSF在动员骨髓造血祖/干细胞同时可能会促进癌细胞释放入血。本课题拟用免疫磁珠分选技术富集循环肿瘤细胞(CTCs)，结合RT-PCR、免疫荧光、荧光原位杂交等技术，计数CTCs数目变化，获取G-CSF促进肿瘤扩散的直接证据；并探讨CTCs生物学特点及其侵袭性与成瘤能力；进而构建可视化大肠癌细胞移植裸鼠转移模型，在此基础上实体动态观察G-CSF对肿瘤生长与转移的作用，并探讨G-CSFR及SDF-1/CXCR4轴在其中的作用；进一步，我们观察G-CSFR中和抗体及CXCR4拮抗剂对阻断G-CSF促肿瘤生长作用的效果，探讨G-CSF影响肿瘤生长及转移的关键环节。

粒细胞集落刺激因子(G-CSF)是临床上防治结直肠癌放化疗后骨髓抑制的常用药物，近年研究表明其可能会促进肿瘤生长，那么，G-CSF 应用于结直肠癌患者是否安全？会否促进肿瘤生长或转移？本课题应用免疫磁珠分选技术富集循环肿瘤细胞(CTCs)结合流式细胞术检测发现连续注射重组人G-CSF后，晚期大肠癌患者外周血CTCs数目明显增加；荧光定量RT-PCR也显示，注射G-CSF后，血浆CEA及CK20 mRNA水平急剧升高，提示G-CSF的连续使用可能会促进隐匿或潜伏病灶中肿瘤细胞的释放，导致肿瘤复发或转移的几率增加。我们进而构建了可视化大肠癌细胞移植裸鼠转移模型；通过动物研究证实，连续注射重组人G-CSF可以促进皮下接种裸鼠肿瘤病灶的快速生长，且随着G-CSF剂量的增加，肿瘤的生长有加速趋势。未来我们将继续深入探讨G-CSF促进肿瘤细胞释放及G-CSF促进局部肿瘤生长的机制，阐明G-CSF影响肿瘤生长及转移的关键环节。