The role of stromal hyaluronic acid during tumour growth in malignant melanoma

恶性黑色素瘤的基质和其他实体瘤一样，是肿瘤细胞附近的良性组织。它由基质组织、基质细胞（免疫细胞、成纤维细胞、肌成纤维细胞）和（微）血管组成，由肿瘤来源的介质以及沉积的基质成分和旁分泌介质控制。肿瘤细胞和基质的相互作用决定性地影响许多实体瘤的生长和转移行为。除了旁分泌诱导细胞外基质组成的变化外，黑色素瘤细胞的行为强烈依赖于由此引起的基质力学和网络结构的变化。基质不同信号的复杂卷积目前限制了对其在肿瘤生物学中特定功能的机制理解，并阻碍了治疗方法。在多种肿瘤支持作用中，间质成纤维细胞诱导间质透明质酸（HA）合成的功能后果尤其如此。该合作项目旨在定性和定量分析依赖于HA在体外和体内呈现的黑色素瘤细胞的行为。该项目将重点研究HA合成酶2 (HAS2)，该酶被发现可由黑色素瘤细胞衍生介质在成纤维细胞中诱导。它被认为是肿瘤基质中HA的主要来源，在体外不能被其他HA合酶拯救。肿瘤基质的协同作用必须与基质血凝素的特定影响分开。这将通过在体外使用复杂程度分级的模型系统来完成。它们包括受刺激的成纤维细胞的脱细胞基质和调节的透明质酸合成，以及具有确定的成分、结构和弹性的仿生基质。基质透明质酸对黑色素瘤细胞的影响将在迁移、增殖和基因表达方面进行表征。这些体外研究将与特异性培养条件HAS2敲除小鼠肿瘤生长和转移的体内研究进行比较。作为主要结果，我们将回答肿瘤相关基质中诱导HA合成的肿瘤支持作用是否与基质中HA基于HAS2的发生直接相关。由此，我们将发现，has2相关过程是否可能代表黑色素瘤治疗中假定的抗增殖和抗转移靶点。

The stroma of malignant melanoma represents, like in other solid tumours, the benign vicinity of tumour cells. It consists of the stromal tissue with stromal cells (immune cells, fibroblasts, myofibroblasts) and (micro-)vessels being controlled by tumour-derived mediators as well as deposited matrix components and paracrine mediators. Interactions of tumour cells and the stroma decisively influence growth and metastatic behaviour of many solid tumours.Besides the paracrine induction of changes in the extracellular matrix composition, the behaviour of melanoma cells strongly depends on resulting changes of mechanics and network structure of the matrix. The complex convolution of the diverse cues of the stroma currently limits the mechanistic understanding of their specific functions in tumour biology and impede therapeutic approaches. This is especially true for the functional consequences of the induced synthesis of stromal hyaluronic acid (HA) by stromal fibroblasts in several tumour-supporting effects. The collaborative project aims to qualitatively and quantitatively analyse the behaviour of melanoma cells in dependence on the presentation of HA in vitro and in vivo. The project will focus on the HA synthase 2 (HAS2), which was found to be induced in fibroblasts by melanoma cell derived mediators. It is known as the major source of HA in the tumour stroma that is not rescued by other HA synthases in vitro.The synergistic influences of the tumour stroma have to be separated from the specific impacts of stromal HA. This will be accomplished by the in vitro usage of model systems of graded complexity. They consist of decellularised matrices of stimulated fibroblasts with modulated HA synthesis and biomimetic matrices with defined composition, structure and elasticity. The impact of stromal HA on melanoma cell will be characterized in respect to migration, proliferation and gene expression. These in vitro studies will be compared to in vivo studies on tumour growth and metastasis in specifically raised conditional HAS2 knockout mice.As the main result, we will answer the question whether the tumour-supporting effects of the induced HA synthesis in the tumour-associated stroma can be directly related to the HAS2 based occurrence of HA in the stroma. By that we will find out, whether HAS2-related processes might represent putative anti-proliferative and -metastatic targets in melanoma therapy.