TUMOR-HOST INTERACTIONS IN HUMAN MELANOMA METASTASIS

背景：我们最近发现了一个过程的证据 是肿瘤转移的重要早期因素，即‘克隆优势’ 具有转移能力的细胞变异体导致的原发肿瘤。简单地说， 这样的细胞不仅拥有定居和生长的机械 遥远的器官部位，而且比起 它们在原发部位本身内的非转移性对应物。这 这一过程对肿瘤生物学和 临床肿瘤学不是最小的，它可能是必要的 远处转移的形成。原始人的进化 放射状生长期(RGP)或“薄”的恶性黑色素瘤 垂直生长阶段(VGP)到较厚的VGP阶段提供了 转移细胞‘克隆优势’模型的引人注目的例子。这个 这个项目的主要长期目标是确定一些 原发肿瘤局部环境的正常细胞可能通过哪些途径 黑色素瘤可能导致该病的“生长主导性” 具有转移能力的人类黑色素瘤细胞。 最新相关发现：正常人皮肤成纤维细胞的共培养 与人类黑色素瘤细胞可以在某种程度上调节后者的生长 这是肿瘤进展的一个可重复的函数：RGP或早期VGP (转移能力不强)细胞生长受到抑制，而黑色素瘤 取自晚期VGP原发肿瘤或远处转移的细胞 刺激了经济增长。此外，这些结果可以通过以下方式复制 使用来自正常人皮肤成纤维细胞的条件培养液，因此 暗示与分泌的生长因子有关。初步 实验表明，该抑制剂是一种具有分子质量的蛋白质。 28-48kda之间，且转铁蛋白(Tf)或类Tf分子为 成纤维细胞对转移性黑色素瘤的刺激作用 细胞。 总的指导假设和意义：假设 原发人类黑色素瘤中转移细胞的克隆性优势 部分受旁分泌生长因子联合作用的影响 成纤维细胞释放的抑制物和刺激物。增长 抑制剂被认为对早期(非转移性)有效 黑色素瘤细胞，但在更晚期(转移- 有能力的)子群体--而相反的假设是 刺激性生长因子活性。远处转移生长也可能 通过成纤维细胞的存在而变得更容易 化肥有助于为肿瘤创造更适宜的环境 成长。 具体目标：包括以下内容：(I)多步纯化蛋白质 并将进行分子克隆程序以识别 抑制物的性质(称为人真皮成纤维细胞来源的生长 抑制剂)，克隆其同源CDNA，并研究其功能 对黑色素瘤细胞体外生长和行为的影响； Tf在成纤维细胞介导的生长刺激中的可能辅助因子 将确定具有转移能力的黑色素瘤细胞； 成纤维细胞黑色素瘤生长的特异性和异质性 将评估相互作用；(Iv)抑制性因素的贡献 和刺激生长因子活性对人黑色素瘤生长和 体内的进展将被研究。

Background: We recently uncovered evidence for a process which appears to be a vital early element of metastasis, namely 'clonal dominance' of primary tumors by metastatically-competent cell variants. Simply put, such cells not only possess the machinery to colonize and grow in distant organ sites, but also have a profound growth advantage over their non-metastatic counterparts within the primary site itself. This process has several far-reaching implications for tumor biology and clinical oncology not the least of which that it may be necessary for the formation of distant metastases. The progression of primary human malignant melanomas from the radial growth phase (RGP) or 'thin' vertical growth phase (VGP) stages to the thicker VGP stage provides a compelling example of the metastatic cell 'clonal dominance' model. The major long-term objective of this project is to determine some of the possible ways by which normal cells of the local environment of primary melanomas may contribute to the 'growth dominant' nature of metastatically-competent human melanoma cells. Recent Pertinent Findings: Coculture of normal human dermal fibroblasts with human melanoma cells can modulate the growth of the latter in a way that is reproducibly a function of tumor progression: RGP or early VGP (metastatically-incompetent) cells are growth inhibited whereas melanoma cells obtained from advanced VGP primary tumors or distant metastases are growth stimulated. Moreover, these results can be duplicated by using conditioned media from normal human dermal fibroblasts, thus implicating the involvement of secreted growth factors. Preliminary experiments indicate the inhibitor is a protein of molecular mass between 28 and 48 Kda, and that transferrin (Tf) or Tf-like molecule is involved in the fibroblast-mediated stimulation of metastatic melanoma cells. Overall Guiding Hypotheses and Significance: It is hypothesized that clonal dominance of metastatic cells in primary human melanomas is in part mediated by the combined effects of paracrine growth factor inhibitors and stimulators liberated by fibroblasts. The growth inhibitor is postulated to be effective on early-stage (non-metastatic) melanoma cells but impotent on more advanced stage (metastatically- competent) subpopulations-- whereas the reverse is postulated for the stimulatory growth factor activity. Distant metastatic growth may also be facilitated by the presence of fibroblasts acting as a 'cellular fertilizer' to help create a more congenial environment for tumor growth. Specific Aims: Include the following: (i) multistep protein purification and molecular cloning procedures will be undertaken to identify the nature of the inhibitor (called human dermal fibroblast-derived growth inhibitor or 'hDFGI'), clones its cognate CDNA, and study its function on melanoma cell growth and behavior in vitro; (ii) the contribution of Tf as a possible co-factor in fibroblasts-mediated growth stimulation of metastatically-competent melanoma cells will be determined; (iii) the specificity and heterogeneity of the fibroblast-melanoma growth interaction will be evaluated; (iv) the contribution of the inhibitory and stimulatory growth factor activities to human melanoma growth and progression in vivo will be investigated.