ROLE OF EGF-RELATED PEPTIDES IN THE PATHOGENESIS OF BREAST AND COLON CANCER

EGF 相关肽在乳腺癌和结肠癌发病机制中的作用

• 批准号: 3752065
• 负责人: D S SALOMON
• 金额: --
• 依托单位: DIVISION OF CANCER BIOLOGY AND DIAGNOSIS
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3752065
• 关键词: MCF7 cell; antireceptor antibody; antisense nucleic acid; autocrine; blocking antibody; breast neoplasms; cell growth regulation; chloramphenicol acetyltransferase; colon neoplasms; epidermal growth factor; estrogens; gene expression; genetic promoter element; growth factor receptors; hormone regulation /control mechanism; human tissue; messenger RNA; molecular oncology; neoplastic process; neutralizing antibody; protein biosynthesis; protooncogene; receptor binding; transfection; transforming growth factors

Transforming growth factor a (TGFalpha), amphiregulin (AR) and cripto-1 (CR-1) are proteins that are structurally and in some cases functionally related to epidermal growth factor (EGF) in that TGFalpha and AR can bind to the EGF receptor (c-erb B). TGFalpha has been circumstantially implicated in the autocrine growth of a number of different human carcinoma cells such as breast and colon tumors. However, the regulation of expression of this growth factor and interference with its biological activity have not been thoroughly examined. Moreover, the relative levels of expression and biological function of AR and CR-1 in these malignancies are unknown. The present studies have demonstrated that MCF-10A human mammary epithelial cells are mitogenically responsive to exogenous EGF, TGFalpha or AR and that transformation of these cells with a point-mutated c-Ha-ras protooncogene but not with a c-erb B-2 protooncogene results in an increase in the expression of endogenous TGFalpha. Furthermore, overexpression of a human TGFalpha cDNA in these cells leads to their in vitro transformation. Addition of an anti-EGF receptor blocking antibody or an anti-TGFalpha neutralizing antibody can partially or completely inhibit the growth of the Ha-ras or TGFalpha transformed mammary cells suggesting that an external autocrine loop is operative in these cells. In contrast, AR expression is increased in both Ha-ras and c-erb B-2 transformed MCF-10A cells and the growth of these transformants can be inhibited by AR antisense phosphorothioate oligonucleotides demonstrating that AR is functioning as an autocrine intermediary in the transformation pathway that is utilized by both Ha-ras and erb B-2. Estrogens can increase the expression of TGFalpha mRNA and protein in estrogen- responsive human breast cancer cell lines such as MCF-7 or ZR-75-1 cells. Transient transfection assays in MCF-7 or ZR-75-1 cells using a plasmid containing the TGFalpha promoter ligated to either the chloramphenicol acetyltransferase (CAT) or luciferase genes have demonstrated that physiological concentrations of estrogens can induce a 5-to 50-fold increase in the activity of these reporter genes, suggesting that the TGFalpha promoter contains a cis-acting estrogen-responsive element(s) (ERE). MCF-7 or ZR-75-1 cells were infected with a recombinant amphotropic TGFalpha antisense mRNA expression vector. Expression of this antisense mRNA lead to a reduction in estrogen-induced TGFalpha protein production and to an equivalent degree of inhibition of estrogen-induced proliferation in these cells. Specific mRNA and immunoreactivity for AR and CR-1 have been detected in approximately 50% to 80% of primary and metastatic human colorectal tumors, whereas only 5% of normal adjacent colon or liver tissue express these genes. Likewise, immunoreactive AR and CR-1 was detected in approximately 70% of primary human breast tumors at a level that exceeded the level found in adjacent normal mammary epithelium.

转化生长因子α、两调节蛋白和CRIPTO-1 (cr-1)是结构上和某些情况下具有功能的蛋白质 与表皮生长因子(EGF)有关，因为TGFα和AR可以结合 与EGF受体(c-erb B)结合。TGFAlpha一直是间接的 牵涉到许多不同人类的自分泌生长 癌细胞，如乳腺和结肠肿瘤。然而，这项规定 该生长因子的表达及其对其生物学特性的干扰 活动尚未得到彻底检查。此外，相对水平 AR和CR-1在这些恶性肿瘤中的表达及其生物学功能 都是未知的。目前的研究表明，MCF-10A人类 乳腺上皮细胞对外源性EGF有丝分裂反应， 转化生长因子α或AR及这些细胞转化点突变 C-Ha-ras原癌基因但不与c-erb B-2原癌基因一起导致 内源性转化生长因子α表达增加。此外， 人转化生长因子α基因在这些细胞中的过表达导致它们的 体外转化。添加抗EGF受体封闭抗体 或者抗肿瘤生长因子α中和抗体可以部分或完全 抑制Ha-ras或TGFα转化的乳腺细胞的生长 这表明在这些细胞中有一个外部自分泌环路起作用。在……里面 相反，AR在Ha-ras和c-erb B-2中的表达均增加 转化的MCF-10A细胞和这些转化子的生长可以 AR反义硫代寡核苷酸抑制作用的研究 AR在转型中起着自分泌中介的作用 Ha-ras和erb B-2都利用的途径。雌激素可以 增加雌激素对TGFα基因和蛋白表达的影响 敏感的人乳腺癌细胞系，如MCF-7或ZR-75-1细胞。 用质粒瞬时转染MCF-7或ZR-75-1细胞 含有连接到氯霉素的TGFα启动子的 乙酰基转移酶(CAT)或荧光素酶基因已经证明 生理浓度的雌激素可以诱导5到50倍的 这些报告基因的活性增加，表明 转化生长因子α启动子含有一个顺式作用的雌激素反应元件(S) (这里)。重组两性致病因子感染MCF-7或ZR-75-1细胞 转化生长因子α反义mRNA表达载体。表达这种反义 MRNA导致雌激素诱导的转化生长因子α蛋白生成减少 和同等程度的雌激素诱导的抑制 在这些细胞中的增殖。AR的特异性mRNA及其免疫反应性 和CR-1在大约50%到80%的小学和 转移性人类结直肠肿瘤，而正常结直肠肿瘤仅5% 结肠或肝脏组织表达这些基因。同样，免疫反应性AR和 在大约70%的原发人类乳腺肿瘤中检测到CR-1 水平超过邻近正常乳腺的水平 上皮组织。