INVOLVEMENT OF STEM-LIKE CELLS IN MODELS OF SPONTANEOUS TRANSFORMATION

这个子项目是利用资源的许多研究子项目之一 由NIH/NCRR资助的中心拨款提供。次级项目的主要支助 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， NCRR赠款不直接向子项目或子项目工作人员提供资金。 尽管对人类和啮齿动物肝癌进行了广泛的研究，但肝癌干细胞仍然难以识别。越来越多的证据支持这样一种模型，即肿瘤干细胞在衰老过程中通过基因突变从正常干细胞中产生，这些基因突变导致正常细胞过程失调。由此产生的癌症干细胞进而获得一组独特的特征，包括自我更新和产生异质子细胞群体的能力，这是肿瘤存活和繁殖所需的特性。在以前的研究中，我们已经表明，随着持续传代（p），大鼠胆管上皮细胞（BDEC）积累了肿瘤特征，其中一些或全部是诱导锚定非依赖性生长和致瘤性所需的激活ErbB-2/Neu。简言之，在传代中期（p31-84），BDEC表现出形态学改变，出现非整倍体，生长速率增加，生长因子不依赖性，细胞粘附减少，低传代时表达的胆管细胞标志物丢失（p85），表达活化、酪氨酸磷酸化ErbB-2/Neu的BDEC数量增加，并在软琼脂上表现出锚定不依赖性生长。 基于我们实验室使用BDEC和PEC模型生成的数据，我们假设软琼脂侵袭试验选择具有高度自我更新的化学耐药细胞亚群，这一特征使这些细胞能够维持和扩大实体瘤进展。为了实现这一目标，我们将检查这些细胞的耐药性，致瘤性，并沿着内胚层谱系移植到大鼠肝脏分化的能力。我们还将研究软琼脂侵袭衍生的微泡脱落的作用，作为微泡货物的水平转移（例如，蛋白质，微小RNA）与邻近细胞的结合可以赋予起源肿瘤选择性存活优势。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Despite extensive study of human and rodent liver cancer, liver cancer stem cells remain difficult to identify. Increasingly, evidence supports a model where tumor stem cells arise from normal stem cells during the aging process through genetic mutations that contribute to dysregulation of normal cell processes. The resulting cancer stem cell in turn acquires a unique set of characteristics including the ability to self-renew and give rise to heterogeneous populations of daughter cells, properties needed for tumor survival and propagation. In previous studies, we have shown that with continued passage (p), rat bile duct epithelial cells (BDEC) accumulated neoplastic characteristics, some or all of which were required for the induction of anchorage independent growth and tumorigenicity by activated ErbB-2/Neu. Briefly, by mid-passage (p31-84), BDEC showed alterations in morphology, onset of aneuploidy, increased growth rate with growth factor independence, decreased cell adhesion and loss of cholangiocyte markers expressed at low passage (p85), an increasing number of BDEC expressed activated, tyrosine phosphorylated ErbB-2/Neu and exhibited anchorage independent growth on soft agar. Based on data generated in our laboratory using the BDEC and PEC models, we hypothesize that the soft agar invasion assay selects for a subpopulation of chemoresistant cells with high self-renewal, a characteristic that enables these cells to sustain and expand solid tumor progression. To accomplish this goal we will examine these cells for chemoresistance, tumorigenicity, and the ability to differentiate along an endodermal lineage when transplanted into rat liver. We will also investigate the role of soft agar invasive-derived microvesicle shedding, as horizontal transfer of microvesicle cargo (e.g., proteins, microRNA) to neighboring cells may impart a selective survival advantage to the originating tumor.