Ongoing inflammation following chemotherapy induces immunosuppression

传统的化疗被认为是通过直接杀死肿瘤细胞来起作用的。然而，在这方面， 越来越多的证据表明，免疫能力是化疗效果所必需的。是 预期在化疗期间这种免疫力的丧失对其功效具有负面影响。因此 化疗对抗肿瘤免疫的影响有待进一步研究，以便合理设计化疗方案。 常规化疗的组合方案。在初步研究中，我们已经证明， 重复化疗药物吉西他滨（GEM）治疗促进了扩增和分化， 免疫抑制性Ly 6Chigh单核细胞-MDSC（M-MDSC）。肿瘤来源的可溶性因子，如GM-CSF和 可溶性ICAM-1（sICAM-1）在化疗药物治疗后上调。在无肿瘤的幼稚小鼠中，GEM 治疗诱导了骨髓（BM）中Ly 6C高骨髓细胞的免疫抑制活性。的 趋化因子CX 3CL 1及其受体CX 3CR 1的表达水平在BM中升高。更高水平的 在肿瘤细胞和骨髓基质细胞中也观察到线粒体活性氧（mtROS）， 化疗此外，化疗诱导NF-κB活化，导致GM-CSF的过度产生 肿瘤细胞。基于这些初步的数据，我们假设化疗增强了 肿瘤细胞和骨髓基质细胞中的线粒体活性氧（mtROS），使GM-CSF和sICAM-1的表达增加 作为CX 3CL 1，导致TME中M-MDSC的免疫抑制增强。这些假设将是 有两个具体目标。目的1明确GM-CSF和sICAM-1在化疗诱导的肿瘤细胞凋亡中的作用 免疫抑制性Ly 6C高骨髓细胞的分化和mtROS和 肿瘤细胞中GM-CSF和sICAM-1的上调;目的2确定宿主细胞的机制 衍生趋化因子CX 3CL 1调节炎症因子的积累和免疫抑制功能 骨髓中的Ly 6C高骨髓细胞。这些研究的结果将使我们更好地了解 多剂量临床化疗方案后持续炎症的潜在机制 调节抗肿瘤免疫，合理设计联合化疗的新治疗途径 用抗氧化剂来治疗癌症

Conventional chemotherapy has been thought to act through the direct killing of tumor cells. However, accumulating evidence indicates that immune competence is crucially required for chemotherapy efficacy. It is expected that loss of this immunity during chemotherapy has a negative effect on its efficacy. Therefore, the impact of chemotherapy on anti-tumor immunity needs further investigation in order to rationally design combinatorial regimens for conventional chemotherapy. In the preliminary studies, we have demonstrated that repeated chemodrug gemcitabine (GEM) treatment promoted the expansion and differentiation of immunosuppressive Ly6Chigh monocytic-MDSC (M-MDSC). Tumor-derived soluble factors, such as GM-CSF and soluble ICAM-1(sICAM-1), were up-regulated upon chemo-drug treatment. In tumor-free naïve mice, GEM treatment induced the immunosuppressive activity of Ly6Chigh myeloid cells in the bone marrow (BM). The chemokine CX3CL1 and its receptor CX3CR1 expression levels were elevated in the BM. Higher levels of mitochondrial reactive oxygen species (mtROS) were also observed in tumor cells and BM stromal cells following chemotherapy. Furthermore, chemotherapy induced NF-κB activation leading to the hyperproduction of GM-CSF by tumor cells. Based on these preliminary data, we hypothesize that chemotherapy enhances the production of mtROS in tumor cells and BM stromal cells, which increases the expressions of GM-CSF and sICAM-1 as well as CX3CL1 leading to the enhanced immunosuppression of M-MDSC in the TME. These hypotheses will be addressed by two Specific Aims. Aim 1 defines the roles of GM-CSF and sICAM-1 in chemotherapy-induced differentiation of immunosuppressive Ly6Chigh myeloid cells and the mechanisms underlying mtROS and upregulation of GM-CSF and sICAM-1 in tumor cells; Aim 2 determines the mechanisms by which host cell- derived chemokine CX3CL1 regulates the accumulation and immunosuppressive function of inflammatory Ly6Chigh myeloid cells in the BM. The findings from these studies will allow us to gain a better understanding the underlying mechanisms by which ongoing inflammation following multi-dose clinical regimens of chemotherapy modulates anti-tumor immunity, and rationally design a novel therapeutic approach by combining chemotherapy with mitochondria-targeted antioxidants for cancer treatment.