免疫治疗联合去势疗法治疗前列腺癌的效果和机制研究

发布时间：2018-04-19 16:24

本文选题：前列腺癌 + 去势治疗　；参考：《华南理工大学》2016年博士论文

【摘要】：去势治疗是当今治疗前列腺癌的主流疗法,包括手术物理去势疗法和化学去势疗法。该疗法常单独使用和或与其他疗法(如放射治疗,化疗等)联合使用来控制前列腺癌。然而大部分前列腺癌患者在接受治疗一定时间后都会出现肿瘤复发,复发后的肿瘤会从去势敏感型前列腺癌发展为去势抵抗性前列腺癌,使得去势(抗雄激素)治疗收效甚微。免疫治疗已成为当前最重要的癌症治疗方案之一,借助人体自身免疫系统控制肿瘤的同时显著减少传统治疗带来的副作用。因此,探索去势抵抗性前列腺癌的具体发生机制并合理设计抗雄激素治疗和免疫治疗的联合治疗方案具有重要临床意义。本研究揭示了经典化学去势药物——非甾体类雄激素受体拮抗剂通过抑制T细胞活化,削弱免疫治疗与抗雄激素疗法联合治疗前列腺癌抗肿瘤效果的具体机制。为此,本研究首先建立了免疫系统健全的野生型FVB小鼠接种Myc-CaP肿瘤的去势半抵抗性前列腺癌模型。该模型表现为荷瘤小鼠经过抗雄激素治疗后,肿瘤负荷在治疗初期显著降低,但随后肿瘤复发并发展为去势抵抗性前列腺癌,对传统抗雄激素治疗出现耐药。小鼠实验中,运用免疫治疗分别联合手术去势疗法和化学去势疗法治疗Myc-CaP前列腺癌,我们发现只有联合手术去势疗法与免疫治疗能够产生协同抗肿瘤作用,而联合化学去势疗法与免疫治疗的抗肿瘤效果甚微。本研究进一步实验发现,当前主流的非甾体类雄激素受体拮抗剂氟他胺、恩泽鲁氨等会抑制机体免疫系统的活化。使用HSV-1小鼠感染模型和卵清蛋白为模式抗原验证了非甾体类雄激素受体拮抗剂会对机体适应性免疫系统(包括体液免疫和细胞免疫)产生广谱影响,不具有Myc-Cap肿瘤抗原特异性。利用具有高免疫原性且不依赖于雄激素生长的“退化型”肿瘤模型B16-human EGFRhigh对非甾体类雄激素受体拮抗剂产生的免疫抑制机制进行研究,我们发现无论小鼠在肿瘤接种之前是否接受过去势手术干预,非甾体类雄激素受体拮抗剂给药组的肿瘤均会由“退化型”肿瘤发展为“进展型”肿瘤,说明非甾体类雄激素受体拮抗剂对免疫系统的调控不依赖于雄激素受体信号转导通路。通过体外实验将免疫细胞亚群(T细胞、B细胞、DC细胞,巨噬细胞等)分别进行纯化,对经该类抗雄激素药物处理后各细胞亚群的功能进行细分。结果显示经非甾体类雄激素受体拮抗剂共培养后T细胞活化水平受到显著抑制,表现为IFN-γ和IL-2等细胞因子分泌显著减少,仅为溶剂对照组分泌水平的1/3。此外,B细胞及固有免疫细胞的功能并未受此影响。进一步研究发现,该类抗雄激素药物通过作用于T细胞上的GABA-A受体抑制T细胞活化,进而影响免疫系统产生有效抗肿瘤免疫反应。在小鼠模型中,GABA-A受体拮抗剂在与该类抗雄激素药物同时给药治疗前列腺癌荷瘤小鼠时,会对免疫细胞上的GABA-A受体与雄激素受体拮抗剂产生竞争性结合,能够缓解雄激素受体拮抗剂介导的免疫抑制反应。由于雄激素受体拮抗剂会影响T细胞早期激活阶段细胞因子IL-2和反应T细胞功能细胞因子IFN-γ的减少,选取与T细胞早期激活相关的经典信号通路JNK、ERK、MAPK、NFAT等进行检验后发现非甾体类雄激素受体拮抗剂给药组中NFAT通路的去磷酸化和核定位较溶剂对照组发生显著变化,说明这类药物通过影响NFAT的去磷酸化从而调控钙离子浓度影响T细胞活化。以此发现为基础,我们对免疫治疗及化学去势疗法联合治疗方案的给药时间和药物选择进行了优化,设计了具有协同效应的抗雄激素治疗和免疫治疗联合方案,即先使用免疫治疗激活机体的免疫系统再对其进行去势治疗。此外,我们使用了一种新型抗雄激素合成的化学去势药物——阿比特龙,联合免疫疗法治疗前列腺癌,首次在小鼠模型中成功抑制了肿瘤复发,高剂量的阿比特龙与免疫治疗相结合的联合治疗方案可使荷瘤小鼠治疗后生存率达100%。综上所述,我们的研究揭示了非甾体类雄激素受体拮抗剂对免疫系统的负性调控是免疫治疗和化学去势治疗联合疗法无法取得理想疗效的关键。在半去势抵抗性前列腺癌中,合理设计抗雄激素药物和免疫治疗联合的抗肿瘤治疗方案,优化给药顺序和剂量可以增强联合治疗的临床疗效。本研究揭示了前列腺癌治疗中一个易被忽视的关键问题,为今后更合理的设计化学去势疗法和免疫治疗的联合方案提供了科学依据和理论基础。
[Abstract]:Castration is the mainstream therapy for the treatment of prostate cancer today, including surgical physical castration and chemical castration. This therapy is often used alone and combined with other therapies (such as radiation therapy, chemotherapy, etc.) to control prostate cancer. However, most of the prostate cancer patients have a tumor relapse after a certain period of treatment. The recurrent tumor develops from castration sensitive prostate cancer to castration resistant prostate cancer, which makes the castration (anti androgen) treatment less effective. Immunotherapy has become one of the most important cancer treatment options at present. It reduces the side effects of traditional treatment with the help of the human body's autoimmune system and reduces the side effects of traditional treatment. This is of important clinical significance in exploring the specific mechanism of castrated resistance to prostate cancer and the rational design of a combination of anti androgen therapy and immunotherapy. This study revealed that the classical chemical castration drug, the non steroid androgen receptor antagonist, reduces the immunotherapy and androgen therapy by inhibiting T cell activation. In this study, this study first established a castrated semi resistant prostate cancer model with a healthy immune system of FVB mice inoculated with Myc-CaP tumor. The model showed that after anti androgen treatment, the tumor load decreased significantly at the beginning of the treatment, but then swollen. The tumor recurs and develops into castrated resistant prostate cancer and is resistant to traditional antiandrogenic therapy. In mice, we used immunotherapy to combine surgical castration and chemical castration for Myc-CaP prostate cancer, and we found that only combined surgical castration and immunotherapy can produce synergistic antitumor effects. The antitumor effect of combined chemical castration therapy and immunotherapy was very slight. Further experiments in this study found that the current mainstream non steroid androgen receptor antagonist fluatamine, Enze Lu ammonia, etc. would inhibit the activation of the immune system. The HSV-1 mice infection model and ovalbumin were used as model antigens to verify the non steroid androgen receptor. Body antagonists can produce broad-spectrum effects on the body's adaptive immune system (including humoral and cellular immunity), and do not have the specificity of Myc-Cap tumor antigen. Using a "degenerate" tumor model, which has high immunogenicity and does not depend on androgen growth, B16-human EGFRhigh against non steroid androgen receptor antagonists We found that no matter whether the mice received the past potential operation before the tumor inoculation, the tumor of the non steroid androgen receptor antagonist could develop from the "degenerative" tumor to the "progressive" tumor, indicating that the regulation of the non steroid androgen receptor antagonist on the immune system is not dependent on Yu Xiong. Cell subsets of immune cells (T cells, B cells, DC cells, macrophages, etc.) were purified respectively through in vitro experiments to subdivide the function of each cell subgroup after the treatment of this anti androgen drug. The results showed that the activation level of T cells after the co culture of non steroid androgen receptor antagonists was displayed. Inhibition, the secretion of cytokines such as IFN- gamma and IL-2 decreased significantly, only 1/3. of the secretory level in the solvent control group, and the function of B cells and innate immune cells was not affected. Further studies found that the anti androgen drugs can inhibit the activation of T cells by acting on the GABA-A receptors on T cells and then affect the immune system. In the mouse model, the GABA-A receptor antagonist, when combined with this antiandrogenic drug, can combine the GABA-A receptor on the immune cells with the androgen receptor antagonist and alleviate the immunosuppressive reaction mediated by the androgen receptor antagonist. As androgen receptor antagonists affect the reduction of cytokine IL-2 in the early activation phase of T cells and the functional cytokine IFN- gamma of reactive T cells, select the classical signaling pathway related to the early activation of T cells, JNK, ERK, MAPK, and NFAT, to detect the dephosphorylation of NFAT pathway in the drug group of non steroid androgen receptor antagonist. There is a significant change in the nucleation and nuclear location of the solvent control group, indicating that these drugs regulate the effect of the dephosphorylation of NFAT and regulate the calcium ion concentration to affect the activation of T cells. Based on this discovery, we optimized the time of administration and drug selection for the combination of immunotherapy and chemical castration therapy, and designed a synergistic effect. The combination of anti androgen therapy and immunotherapy, which first uses immunotherapy to activate the body's immune system, carries out its castration treatment. In addition, we have used a new anti androgen synthesis chemical castration drug, a combined immunotherapy for prostate cancer, for the first time in a mouse model. The tumor recurrence, the combination of high dose of aslong and immunotherapy can make the survival rate of the tumor bearing mice treated with 100%.. Our study reveals that the negative regulation of the non steroid androgen receptor antagonist on the immune system is that the combined therapy of immunotherapy and chemical castration therapy can not achieve ideal treatment. In the case of semi castrate resistance to prostate cancer, the rational design of antiandrogenic and immunotherapy combined with antitumor therapy, optimization of drug delivery order and dosage can enhance the clinical efficacy of combined therapy. This study reveals a key problem that is easily ignored in the treatment of prostate cancer and for a more reasonable design chemistry in the future. The combination of castration and immunotherapy provides a scientific basis and theoretical basis.

【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R737.25

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