MCP-3高表达介导肺癌干细胞促血管生成并诱导贝伐单抗治疗耐药

发布时间：2018-11-29 10:08

【摘要】：肿瘤干细胞定位于血管周围,依靠血管微环境维持自我更新和干性特征。反之,肿瘤干细胞也能促进血管生成,进而维持肿瘤的发生发展。然而,不同肿瘤干细胞在血管生成中的作用及其作用机制,以及对抗血管生成治疗的反应均不同。本研究将探索肺癌干细胞在肿瘤血管生成中的作用及其作用机制,并观察其对抗VEGF药物贝伐单抗的治疗疗效。本实验中,我们采用全克隆悬浮培养法分离提取肺癌干细胞,并通过体内外实验对比肺癌干细胞与普通肿瘤细胞在肿瘤血管生成方面的差异。结果发现,与普通肿瘤细胞来源的肿瘤相比,肺癌干细胞来源的移植瘤微血管密度明显增高,并且对贝伐单抗治疗不敏感。体外实验中也观察到肺癌干细胞与内皮细胞共培养明显促进内皮细胞的增殖、迁移、侵袭和成管,并且该促进作用不能被贝伐单抗阻断。为了探索肺癌干细胞促血管生成的机制,我们采用抗体芯片检测了上清中血管生成相关因子的表达差异。结果发现,肺癌干细胞共培养上清中MCP-3和Angiogenin高表达,而VEGF却低表达。外源性给予MCP-3,可增强MCP-3低表达组中(普通肿瘤细胞和内皮共培养或内皮单独培养)内皮细胞的增殖和成管等生物特性,诱导贝伐单抗治疗不敏感：中和上清中MCP-3,则抑制了肺癌干细胞共培养组中内皮细胞的上述生物特性,部分逆转了贝伐单抗治疗耐药。此外,我们研究还发现PI3K/Akt/mTOR信号通路可能介导肺癌干细胞微环境中MCP-3的高表达。综上,肺癌干细胞具有促进肿瘤血管生成的作用,并对贝伐单抗治疗耐药。干细胞微环境中MCP-3的高表达介导了肺癌干细胞的非VEGF依赖性促血管生成作用,并诱导贝伐单抗治疗耐药。本研究不但丰富了肺癌抗血管生成治疗耐药的理论,而且为增强抗血管生成治疗疗效提供了新靶点。靶向MCP-3,不仅有望抑制肺癌的血管生成,而且还可破坏肿瘤干细胞的微环境,抑制干细胞的更新和存活。
[Abstract]:Tumor stem cells are located around blood vessels and rely on vascular microenvironment to maintain self-renewal and dry characteristics. Conversely, tumor stem cells can also promote angiogenesis, thereby maintaining tumor development. However, the role and mechanism of different tumor stem cells in angiogenesis and the response of antiangiogenic therapy are different. The aim of this study was to explore the role and mechanism of lung cancer stem cells in tumor angiogenesis, and to observe the therapeutic effect of lung cancer stem cells against the VEGF drug bevacizumab. In this experiment, lung cancer stem cells were isolated and extracted by whole clone suspension culture, and the difference of tumor angiogenesis between lung cancer stem cells and normal tumor cells was compared in vivo and in vitro. The results showed that the microvessel density of transplanted tumor derived from lung cancer stem cells was significantly higher than that of normal tumor cells, and was not sensitive to bevacizumab therapy. It was also observed in vitro that co-culture of lung cancer stem cells and endothelial cells significantly promoted the proliferation, migration, invasion and tubulogenesis of endothelial cells, and this effect could not be blocked by bevacizumab. In order to explore the mechanism of angiogenesis induced by lung cancer stem cells, we used antibody chip to detect the difference of expression of angiogenic factors in supernatant. The results showed that the expression of MCP-3 and Angiogenin was high in the supernatant of lung cancer stem cell coculture, but the expression of VEGF was low. Exogenous MCP-3, could enhance the biological characteristics of endothelial cell proliferation and tube formation in MCP-3 low expression group (common tumor cells and endothelial co-culture or endothelial culture alone). Induced bevacizumab was insensitive: MCP-3, neutralized supernatant inhibited the above biological characteristics of endothelial cells in lung cancer stem cell co-culture group and partially reversed the drug resistance of bevacizumab. In addition, we also found that PI3K/Akt/mTOR signaling pathway may mediate high expression of MCP-3 in lung cancer stem cell microenvironment. In conclusion, lung cancer stem cells can promote tumor angiogenesis and are resistant to bevacizumab. The high expression of MCP-3 in stem cell microenvironment mediates the VEGF independent angiogenesis of lung cancer stem cells and induces bevacizumab to treat drug resistance. This study not only enriches the theory of anti-angiogenesis in lung cancer, but also provides a new target for enhancing the efficacy of anti-angiogenesis. Targeted MCP-3, can not only inhibit angiogenesis of lung cancer, but also destroy the microenvironment of tumor stem cells and inhibit the regeneration and survival of cancer stem cells.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R734.2

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