Phenolic component of tobacco smoke as tumor promoter

烟草烟雾中的酚类成分作为肿瘤促进剂

基本信息

批准号：
7364736
负责人：
JAGAT J MUKHERJEE
金额：
$ 21.45万
依托单位：
BUFFALO STATE COLLEGE
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-02-01 至 2012-01-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): There is considerable evidence of strong tumor-promoting activity of weakly acidic phenolic fraction of tobacco smoke condensate (TSCPhFr) in polynuclear aromatic hydrocarbons (PAHs)-initiated animals. The identity of the tumor promoting phenolic component(s) in TSCPhFr is not known nor the mechanism(s) underlying its tumor-promoting activity. We observed TSCPhFr at non-cytotoxic concentrations attenuates ()-anti-benzo[a]pyrene-7,8- diol-9,10-epoxide [BPDE]-induced p53/NF-kB responses and promotes anchorage- independent cell growth (AICG) in JB6 cells. DNA damage-induced NF-kB activation has important role in p53- mediated apoptosis. We hypothesize that the tumor promoting activity of TSCPhFr is due to the abrogation of p53 accumulation and its function toward apoptosis in response to DNA damaging PAHs. Our studies include (1) purification of the tumor promoting component(s) from TSCPhFr using reverse phase HPLC, (2) determine the correspondence of inhibition of BPDE-induced p53 response and NFkB activation with apoptosis inhibition and increased AICG activity using chemical and genomic inhibitors, (3) if the findings in aim 2 above are affirmative then determine the effect of TSCPHFr on BPDE-induced p53-mediated NFkB activation (RAF/MAPK pathway), the expression of apoptosis regulatory proteins e.g. cIAP1, cIAP2, survivin and bcl-2 family proteins (Bax and bcl-2), degradation of PARP and activation of caspases, (4) if the findings in aim 2 above are negative, then in BPDE treated cells determine the effect of TSCPhFr on p73 response which is known to be involved in p53- independent apoptosis, and examine the correspondence of the inhibition of p73 response with AICG activity and inhibition of apoptosis using genomic inhibitor and (5) if inhibition of BPDE-induced p53, but not apoptosis, has correspondence with AICG activity then determine whether TSCPhFr can override BPDE-induced cell cycle arrest, inhibit p21WAF1 (p21) transactivation and up-regulate G1 cyclins (D1/D3/E) and associated cdk activities (cdk2, cdk4). In our studies we will use JB6 cl41 cells, a model cell line extensively used for the study of tumor promotion. The overall objective of the proposal is to identify the tumor promoting component/s in TSCPhFr and to understand the underlying mechanism(s) by which the phenolic component(s) elicits tumor promoting effect in PAH-initiated cells. Data obtained from these studies will help in assessing the associated health risk presented by tobacco smoke constituents and will be useful for therapeutic strategies in the prevention of cancer. The findings from studies undertaken in the project will open avenues for further detailed investigations on the mechanism of PAH-initiated tumor promotion by the phenolic fraction of TSC. Identification of tumor promoting phenolic component and understanding of the mechanism(s) by which phenolic component of tobacco smoke exerts its tumor promoting effect will help not only assessing the health risk presented by tobacco smoke constituents but also developing a strategy to eliminate the presence of particular tumor promoting phenolic component/s from tobacco leaf through chemical means or genetic manipulation.

描述（由申请人提供）：有大量证据表明，烟草烟雾冷凝物的弱酸性酚部分（TSCPhFr）对多环芳烃（PAH）引发的动物具有强烈的促肿瘤活性。 TSCPhFr 中促肿瘤酚类成分的身份及其促肿瘤活性的机制尚不清楚。我们观察到非细胞毒性浓度的 TSCPhFr 会减弱 ()-抗苯并[a]芘-7,8-二醇-9,10-环氧化物 [BPDE] 诱导的 p53/NF-kB 反应并促进贴壁无关的细胞生长（ AICG）在 JB6 细胞中。 DNA 损伤诱导的 NF-kB 激活在 p53 介导的细胞凋亡中具有重要作用。我们假设 TSCPhFr 的肿瘤促进活性是由于 p53 积累的消除及其响应 DNA 损伤性 PAH 的细胞凋亡功能。我们的研究包括 (1) 使用反相 HPLC 从 TSCPhFr 中纯化肿瘤促进成分，(2) 使用化学和基因组确定 BPDE 诱导的 p53 反应和 NFkB 激活的抑制与细胞凋亡抑制和 AICG 活性增加的对应关系(3) 如果上述目标 2 的结果是肯定的，则确定 TSCPHFr 对 BPDE 诱导的 p53 介导的 NFkB 激活（RAF/MAPK 途径）、细胞凋亡表达的影响调节蛋白例如cIAP1、cIAP2、生存素和 bcl-2 家族蛋白（Bax 和 bcl-2）、PARP 降解和半胱天冬酶激活，(4) 如果上述目标 2 的结果为阴性，则在 BPDE 处理的细胞中确定 TSCPhFr 的效果已知参与 p53 独立细胞凋亡的 p73 反应，并使用基因组抑制剂检查 p73 反应的抑制与 AICG 活性和细胞凋亡抑制的对应关系， (5) 如果抑制 BPDE 诱导的 p53，但不抑制细胞凋亡，与 AICG 活性相关，则确定 TSCPhFr 是否可以克服 BPDE 诱导的细胞周期停滞，抑制 p21WAF1 (p21) 反式激活并上调 G1 细胞周期蛋白 (D1/D3/ E) 和相关的 cdk 活动（cdk2、cdk4）。在我们的研究中，我们将使用 JB6 cl41 细胞，这是一种广泛用于肿瘤促进研究的模型细胞系。该提案的总体目标是确定 TSCPhFr 中的肿瘤促进成分，并了解酚类成分在 PAH 引发的细胞中引发肿瘤促进作用的潜在机制。从这些研究中获得的数据将有助于评估烟草烟雾成分带来的相关健康风险，并将有助于制定预防癌症的治疗策略。该项目的研究结果将为进一步详细研究 TSC 酚类成分引发的 PAH 引发肿瘤的机制开辟途径。鉴定促进肿瘤的酚类成分并了解烟草烟雾中酚类成分发挥其促肿瘤作用的机制，不仅有助于评估烟草烟雾成分带来的健康风险，而且有助于制定消除特定物质存在的策略。通过化学手段或基因操作从烟叶中提取促进肿瘤的酚类成分。