Synergistic inhibition of tumor initiation of solid human cancers by combined depletion of beta4-integrin on the tumor cells and E-/P-selectin in the tumor stroma

不同实体的人肿瘤细胞在体内作为原发肿瘤，其生长都明显依赖于整合素β 4 （integrin β 4, ITGB4）的表达。在肿瘤基质周围微血管内皮细胞中缺乏E-和p -选择素（E-/ p -选择素- ko）的情况下，肿瘤的形成协同减少。然而，单独使用E-/ p - selection - ko对肿瘤的形成没有影响。在该项目的前期工作中，我们发现itgb4 -缺失（ITGB4-KD）的肿瘤细胞簇显示髓源性抑制细胞（MDSC）的浸润增加，而同时发生E-/ p -选择素- ko的情况并非如此。在3D培养模型中，ITGB4-KD肿瘤细胞通过增加不同趋化因子的释放来吸引更多的白细胞。MDSC以其对肿瘤细胞的生长促进作用而闻名。我们的假设是MDSC需要与肿瘤微血管管腔侧的E-/ p -选择素相互作用才能迁移到发展中的肿瘤中。ITGB4-KD肿瘤细胞似乎特异性依赖于MDSC的生长刺激。如果他们缺乏这种刺激，他们显然更容易抑郁。该计划的目标是通过进一步的分析，在初步数据的基础上证明病理生理和分子关系，将其转移到其他小鼠模型和临床材料中，并使新知识至少在某种程度上可用于人类的治疗应用。因此，继续项目解决了以下关键问题：MDSCs是否对ITGB4- kd肿瘤细胞或正常ITGB4状态的对照细胞也有直接的生长促进作用？与MDSC共同注射是否有助于ITGB4-KD肿瘤细胞在E-/ p -选择素- ko环境中生长？肿瘤微血管内皮细胞是否表达E-/ p -选择素？ MDSC能否与这些分子相互作用？ITGB4-KD和E-/ p - selection - ko是否也协同作用于免疫活性宿主的肿瘤生长？临床患者材料中ITGB4表达与肿瘤相关白细胞/ MDSC之间是否存在负相关？肿瘤细胞上ITGB4的异常糖基化是否适合作为潜在的治疗靶点？

Human tumor cells of different entities are significantly dependent on the expression of integrin beta 4 (ITGB4) for growth as a primary tumor in vivo. In the absence of the E- and P-selectins in the endothelial cells of the micro-vessels of the surrounding tumor stroma (E-/P-selectin-KO), tumor establishment is synergistically reduced. However, E-/P-selectin-KO alone has no effect on tumor establishment. In preliminary work for this project, we found that ITGB4-depleted (ITGB4-KD) tumor cell clusters show an increased infiltration of myeloid-derived suppressor cells (MDSC), which is not the case with simultaneous E-/P-selectin-KO. ITGB4-KD tumor cells attract more leukocytes in 3D culture models by increased release of different chemokines. MDSC are known for their growth-promoting effects on tumor cells. Our hypothesis is that MDSC need to interact with E-/P-selectin on the luminal side of tumor microvasculature to migrate into developing tumors. ITGB4-KD tumor cells appear to be specifically dependent on growth stimuli from MDSC. If they lack this stimulus, they are obviously more prone to anoikis. The aim of the proposed continuation project is to prove the pathophysiological and molecular relationships assumed on the basis of the preliminary data by extensive further analyses, to transfer them to alternative mouse models and clinical material and to make the new knowledge available for a possible therapeutic application in humans, at least to some extent. The continuation project therefore addresses the following key questions: Do MDSCs have a direct growth-promoting effect on ITGB4-KD tumour cells or on control cells with normal ITGB4 status as well? Does co-injection with MDSC help ITGB4-KD tumor cells to grow in the E-/P-selectin-KO environment? Do endothelial cells of tumor microvasculature express E-/P-selectins and can MDSC interact with these molecules? Do ITGB4-KD and E-/P-selectin-KO also act synergistically on tumor growth in an immunocompetent host? Is there an inverse correlation between ITGB4 expression and tumor-associated leukocytes/ MDSC in clinical patient material? Is a potentially functionally important aberrant glycosylation of ITGB4 on tumor cells suitable as a potential therapeutic target?