Molecular basis of arsenic-induced cell transformation

描述（由申请人提供）：砷是一种有充分证据的人类致癌物。我们的目标是解决MAP激酶、p90s6激酶和组蛋白H3是砷诱导的信号转导和细胞转化的介质这一中心假设。特异性目的是：特异性目的1，确定砷诱导的p38激酶是否需要用于砷诱导的细胞转化；特异性目的2，确定c-Jun n末端激酶（JNKs）在砷诱导的细胞转化和凋亡中的作用；特异性目的3，确定p90s6激酶/MAPKAP-K1 （p90RSK）的激活是否参与砷诱导的信号转导和细胞转化；特异性Aim 4，确定p38激酶、JNKs和p90RSK在砷诱导的组蛋白H3磷酸化中的作用，以及组蛋白H3磷酸化在细胞转化中的作用。特异性Aim 1的策略是使用p38激酶抑制剂或显性阴性突变体或siRNA来抑制p38激酶的激活。对于Specific Aim 2，我们将(1)测试是否需要JNK磷酸化失活来发展对砷的抗性表型；(2)检测抑制JNK磷酸化/活化是否会抑制亚砷酸盐诱导的细胞转化或凋亡；(3)检验在抗砷细胞中引入活性JNK突变体是否会导致抗凋亡表型的挽救。对于Specific Aim 3，我们将使用表达p90RSK显性负突变体或siRNA的细胞系和p90RSK缺失的细胞系来抑制p90RSK。对于Specific Aim 4，我们将(1)通过特异性抑制剂、显性阴性突变体、siRNA或基因敲除细胞系阻断JNK、p38和p90RSK的激活；(2)利用表达组蛋白H3 siRNA、组蛋白H3 S10突变为A10、组蛋白S28突变为A28和组蛋白H3野生型的细胞系，研究组蛋白H3在砷诱导的细胞转化中的作用。这些知识将有助于设计更有效和更具体的策略，副作用更少的化学预防砷诱导的癌症。

DESCRIPTION (provided by applicant): Arsenic is a well-documented human carcinogen. Our goal is to address the central hypothesis that MAP kinases, p90 S6 kinases, and histone H3 are mediators of arsenic-induced signal transduction and cell transformation. The Specific Aims are: Specific Aim 1, to determine whether arsenic-induced p38 kinase is required for arsenic-induced cell transformation; Specific Aim 2, to determine the role of c-Jun N-terminal kinases (JNKs) in arsenic-induced cell transformation and apoptosis; Specific Aim 3, to determine whether activation of p90 S6 kinase/MAPKAP-K1 (p90RSK) is involved in arsenic-induced signal transduction and cell transformation; and Specific Aim 4, to determine the role of p38 kinase, JNKs, and p90RSK in arsenic-induced phosphorylation of histone H3 and the role of phosphorylation of histone H3 in cell transformation. The strategy for Specific Aim 1 is to use p38 kinase inhibitors or dominant negative mutants or siRNA to inhibit p38 kinase activation. For Specific Aim 2, we will (1) test whether inactivation of JNK phosphorylation is required for development of resistant phenotype to arsenic; (2) test whether inhibition of JNK phosphorylation/activation will cause inhibition of arsenite-induced cell transformation or apoptosis; (3) test whether introduction of an active JNK mutant into arsenic resistant cells will cause the rescue of the apoptosis-resistant phenotype. For Specific Aim 3, we will inhibit p90RSK using cell lines expressing a dominant negative mutant or siRNA of p90RSK and cell lines which are deficient in p90RSK. For Specific Aim 4, we will (1) block the activation of JNK, p38, and p90RSK by specific inhibitors, dominant negative mutants, siRNA, or gene knockout cell lines; (2) use cell lines expressing siRNA of histone H3, dominant negative mutants (histone H3 S10 mutated to A10, H3 S28 mutated to A28) and histone H3 wild-type to study the role of histone H3 in arsenic-induced cell transformation. Such knowledge will facilitate the design of more effective and specific strategies with fewer side effects for chemoprevention of arsenic-induced cancer.