EGF-R MODULATION AND RESPONSES IN COLON CARCINOMA

结肠癌中EGF-R的调节和反应--研究建议 在本应用中将考察表皮生长因子的作用 血管内皮细胞生长因子受体(EGF-R)和转化生长因子-α(TGF-α)水平 人结肠癌个体生长特性的表达 已经被分成三类的细胞系，它们基于 它们的生物学特征。这三个单元线类别利用 已适应的20多个人结肠肿瘤细胞系的库 在化学定义的无血清培养基中生长，并已 以其分化程度、致瘤性、 在软琼脂中生长并产生粘蛋白。表皮生长因子受体的相互关系 表达和转化生长因子-α的产生对细胞生长的影响将通过 结肠癌组织中受体和因子表达水平的测定 在生长速度和程度上差异很大的细胞系 通过改变外源转化生长因子-α和/或表皮的水平进行分化 生长因子(EGF)以及调节功能性EGF水平 受体在至少两个细胞系中分别来自两个最多的 3种人结肠肿瘤细胞系的表型分化。 这项研究将集中在以下问题上：(I)做得更快 生长中的结肠肿瘤细胞株表达更多功能性的转化生长因子-α，(Ii)是 细胞表面EGF-R水平与EGF-R mRNA水平直接相关 表达，(Iii)转化生长因子-α和表皮生长因子的激活能力是否不同 EGF-R酪氨酸特异性蛋白激酶活性，(Iv)DO转化生长因子-α和EGF 它们产生不同位置氨基的能力不同 EGF-R的酸性磷酸化，以及(V)EGF-R数量是如何改变的 和功能是否影响结肠细胞的生长和分化？借此 更好地理解自然层次之间的关系 转化生长因子-α/表皮生长因子受体的表达与结肠癌细胞生长特性的关系 才能实现。此外，EGF-R数量对基底细胞的影响 生长、细胞生长要求和分化程度 将确定单个结肠细胞系的类别。

EGF-R Modulation and Responses in Colon Carcinoma - The research proposed in this application will examine the role of epidermal growth factor receptor (EGF-R) and transforming growth factor-alpha (TGF-a) levels of expression upon the growth characteristics of individual human colon tumor cell lines that have been grouped into three classes that are based upon their biological characteristics. These three cell line classes draw upon a bank of more than 20 human colon tumor cell lines that have been adapted to growth in chemically defined, serum-free medium and have been characterized in terms of their extent of differentiation, tumorigenicity, growth in soft agarose and production of mucins. The relationship of EGF-R expression and TGF-a production to cell growth will be studied by determining the levels of receptor and factor expression in colon tumor cell lines that diverge widely in their growth rate and extent of differentiation, by varying the level of exogenous TGF-a and/or epidermal growth factor (EGF), as well as by modulating the levels of functional EGF receptor in at least two cell lines from each of the two most phenotypically divergent of the 3 classes of human colon tumor cell lines. This study will focus upon the following questions: (i) do the faster growing colon tumor cell lines express more functional TGF-a, (ii) is the level of cell-surface EGF-R directly related to level of EGF-R mRNA expression, (iii) do TGF-a and EGF differ in their capacity to activate EGF-R tyrosine specific protein kinase activity, (iv) do TGF-a and EGF differ with regard to their capacity to produce different sites of amino acid phosphorylation of the EGF-R, and (v) how does altered EGF-R number and function influence colon cell growth and differentiation? By this approach a better understanding of the relationship between natural levels of TGF-a/EGF-R expression and colon tumor cell growth characteristics will be achieved. Furthermore, the influence of EGF-R number on the basal cell growth, cell growth requirements, and extent of differentiation for individual colon cell line classes will be determined.