Gap Junctions and Cancer Drug Therapy

描述(申请人提供)：缝隙连接(GJS)连接相邻细胞的内部，允许分子和离子在细胞之间的被动通量小于约1 kDa。GJS有可能在几个方面修改传统和非传统癌症疗法，但这方面的研究很少。我建议研究GJS如何改变被称为核糖核苷酸还原酶(RR)抑制剂的化疗药物的细胞毒性。这些药物在细胞中引起核苷酸失衡，我假设通过GJS的核苷酸缓冲将影响RR的毒性。我提出了两个特定的目标来解决这一假设：目标1：分离对RR抑制剂羟基脲(HU)敏感和抗药性的GJ活性和GJ不活性的WB细胞克隆。我们将使用WB-F344(GJ+)和WB-AB1(GJ-)细胞用于这一目的，并将表征HU细胞毒性剂量反应、核苷酸池以及RR活性和表达。目的：研究GJS对HU敏感和耐药细胞共培养过程中细胞毒反应和核苷酸缓冲的影响。将对HU敏感和耐药的GJ+或GJ-细胞与HU共培养并处理，然后对每种类型的细胞的细胞毒性和核苷酸进行定量。这些研究可能导致新的癌症治疗范例和治疗方法。

DESCRIPTION (provided by applicant): Gap junctions (GJs) connect the interiors of neighboring cells and permit the passive cell-to-cell flux of molecules and ions less than approximately 1 kDa. GJs have the potential to modify conventional and non-conventional cancer therapies in several ways, but this has seen little investigation. I propose to investigate how GJs alter the cytotoxicity of chemotherapeutic agents known as ribonucleotide reductase (RR) inhibitors. These agents induce nucleotide imbalances in cells, and I hypothesize nucleotide buffering via GJs will impact RR toxicity. I have proposed two Specific Aims to address the hypothesis: Aim 1: Isolate clones of GJ-competent and GJ-incompetent WB cells that are sensitive and resistant to the RR inhibitor, hydroxyurea (HU). We will use WB-F344 (GJ+) and WB-aB1 (GJ-) cells for this purpose and will characterize HU cytotoxic dose response, nucleotide pools, and RR activity and expression. Aim 2: Quantify the effects of GJs on cytotoxic response and nucleotide buffering in co-cultures of HU-sensitive and resistant cells. HU-sensitive and resistant, GJ+ or GJ- cells will be co-cultured and treated with HU, then cytotoxicity and nucleotides will be quantified in each type of cell. These studies may lead to new cancer therapy paradigms and treatments.