ROLE OF KINASE ONCOGENES IN GROWTH FACTOR ABROGATION AND C-MYC REGULATION

我们研究了多种癌基因在肿瘤中的功能意义。 白介素3在两种髓系依赖细胞中的信号转导 通过检测FCD-P1和32DC13对IL-3的清除能力 并诱导正常情况下的基因表达 受IL-3调节。在这些细胞中，IL-3严密调控 C-myc、c-fos和JunB。我们和其他人展示了有条件的 通过引入温度敏感型(Ts)消除对IL-3的依赖 V-ABL逆转录病毒的构建和其他几种病毒的无条件废除 细胞内酪氨酸激酶癌基因包括src和trk。此外， 这种酪氨酸激酶在调节c-myc方面类似于IL-3。 转录，但与IL-3信号转导不同之处在于TS v-ABL 未能诱导c-fos和JunB，提示IL-3对这两种基因的诱导 基因需要不同的信号通路。与废除相比， 酪氨酸激酶癌基因，我们已经证明外源性v-myc或 C-myc可以完全或部分取消IL-3的要求， 分别进行了分析。在取消IL-3需求方面，v-raf与c-myc具有可比性。 然而，当同时携带raf和myc癌基因的构建体是 被引入依赖IL-3的细胞系，或者如果使用RAF或MyC病毒 超级感染依赖于RAF或MyC因子的克隆， 生成与因子无关的线的频率相当于 酪氨酸激酶癌基因构建。废除并不是由于诱导 涉及IL-3或GM-CSF的自分泌环。这种协同效应的机制 似乎是两条共同需要的路径结合的结果 它们在IL-3信号转导中起作用。这一假设是基于 发现外源性、激活的v-raf的引入没有影响 C-myc、c-fos和JunB的表达。考察其他潜力 IL-3信号转导下游中间体的作用 蛋白激酶C构建于细胞生长和基因调控之上 它的表达及其与其他癌基因协同作用的潜力正在 检查过了。

We have investigated the functional significance of various oncogenes in interleukin-3 (IL-3) signal transduction in two myeloid-dependent cell lines, FCD-Pl and 32DC13, by testing their potential to abrogate IL-3 requirements and to induce the expression of genes which are normally regulated by IL-3. In these cells, IL-3 tightly regulates expression of c-myc, c-fos, and junB. We and others have demonstrated conditional abrogation of IL-3 dependence by introduction of temperature-sensitive (ts) v-abl retroviral constructs and nonconditional abrogation by several other intracellular tyrosine kinase oncogenes including src and trk. Furthermore, this tyrosine kinase mimics IL-3 in its ability to regulate c-myc transcription, yet differs from IL-3 signal transduction in that ts v-abl fails to induce c-fos and junB, suggesting that IL-3 induction of these two genes requires distinct signaling pathways. In comparison to abrogation by tyrosine kinase oncogenes, we have demonstrated that exogenous v-myc or c-myc can either completely or partially abrogate IL-3 requirements, respectively. v-raf is comparable to c-myc in abrogating IL-3 requirements. However, when constructs carrying both raf plus myc oncogenes are introduced into IL-3-dependent lines or if raf or myc viruses are used to superinfect raf- or myc-containing factor-dependent clones, factor-independent lines are generated with frequencies comparable to tyrosine kinase oncogene constructs. Abrogation was not due to induction of autocrine loops involving IL-3 or GM-CSF. The mechanism for this synergism appears to be the result of combination of two jointly required pathways which function in IL-3 signal transduction. This hypothesis is based upon the finding that introduction of exogenous, activated v-raf has no effect upon c-myc, c-fos, and junB expression. To examine other potential downstream intermediates in IL-3 signal transduction, the effects of protein kinase C constructs upon the regulation of cell growth and gene expression, and its potential to synergize with other oncogenes is being examined.