GENETIC ALTERATIONS AND MYLTIPLE MYELOMA--EFFECTS ON CELL GROWTH & APOPTOSIS

尽管多发性骨髓瘤(MM)是浆细胞克隆性增殖的结果，但患者之间的遗传异常具有显著的异质性。促进疾病进展和治疗反应的信号不仅影响增殖潜力，而且还影响细胞凋亡的诱导。这项研究的目的是描述遗传异质性如何影响多发性骨髓瘤细胞的生长、死亡和对治疗剂的反应。在第一个特定目标中，我们将使用骨髓瘤细胞株来检测IL-6和ras、p53、Rb和PTP1C基因突变(SHP-L)对细胞增殖、凋亡信号和治疗反应的影响。我们将通过检测bcl2、bclxl、Bad和bax的表达如何调节促进或保护细胞免受凋亡，以及对半胱氨酸天冬氨酸蛋白酶L(ICE)和半胱氨酸天冬氨酸蛋白酶3(Caspase3)的影响来确定基因改变对骨髓瘤细胞凋亡的影响。我们将确定不同基因改变的骨髓瘤细胞中治疗药物(类固醇、细胞因子、DNA烷基化、抗有丝分裂)如何介导细胞凋亡。我们认为疾病进展或反应的异质性受患者特定的间质相互作用的影响。因此，我们将在体外测定基质共培养中基因改变的骨髓瘤细胞对治疗药物的敏感性。我们的体外研究的一个扩展将是将增殖和凋亡对非活动期和活动期疾病进展的影响联系起来。在具体目标2中，我们将开发一种新的浆细胞生长指数，该指数将从标记指数和凋亡分数的测量中推导出来。

Although multiple myeloma (MM) results from a clonal expansion of plasma cells, there is significant heterogeneity in genetic abnormalities among patients. Contributing to disease progression and response to therapy are signals that affect not only the proliferative potential but also induction of apoptosis. The goal of this study is to characterize how genetic heterogeneity affects the growth, death and response of MM cells to therapeutic agents. In the first Specific Aim we will use myeloma cell lines to examine the effects of IL-6 and genetic alterations in ras, p53, Rb, and PTP1C (SHP-l) on cell proliferation, apoptotic signaling, and therapeutic response. We will determine how genetic alterations affect apoptosis in myeloma by determining how expression of bcl-2, bcl-xL, bad and bax are regulated to enhance or protect cells from apoptosis, and the influence on caspase l (ICE) and caspase 3. We will determine how apoptosis is mediated by therapeutic agents (steroids, cytokines, DNA alkylating, anti- mitotic) in myeloma cells with different genetic alterations. We believe that heterogeneity in disease progression or response is influenced by patient specific stromal interactions. Therefore, we will determine in vitro sensitivities of genetically altered myeloma cells to therapeutic agents in stromal co-cultures. An extension of our in vitro studies will be to correlate the influence of proliferations and apoptosis on disease progression in inactive and active disease. In Specific Aim 2 we will develop a novel plasma cell growth index that will be derived from the labeling index and measures of apoptotic fraction.