Role of a Novel Lysophospholipase in Tumorigenesis

新型溶血磷脂酶在肿瘤发生中的作用

• 批准号: 8018083
• 负责人: YING HUANG
• 金额: $ 28.44万
• 依托单位: UPSTATE MEDICAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8018083
• 关键词: Antibodies; Biological Process; Cell Proliferation; Cell Survival; Code; Colon; Colon Carcinoma; Colonic Neoplasms; Colorectal; Complementary DNA; Development; Diagnostic; Down-Regulation; Epigenetic Process; Gastrointestinal tract structure; Gene Expression; Genetic; Growth; Homeostasis; Human; Immunohistochemistry; Incidence; Laboratories; Lipase; Lipids; Lysophospholipase; Lysophospholipids; Malignant Neoplasms; Mediating; Messenger RNA; Mitogens; Molecular; Molecular Mechanisms of Action; Mucous Membrane; Mus; Mutate; Names; Normal Cell; Normal tissue morphology; Outcome Study; Phospholipids; Physiological; Prognostic Marker; Proteins; Role; Signal Pathway; Site-Directed Mutagenesis; Specimen; Testing; Tissues; Transcript; Transgenic Mice; Triad Acrylic Resin; Tumor Suppressor Proteins; Western Blotting; base; cancer cell; cell growth; cell growth regulation; colon cancer cell line; enzyme activity; mRNA Expression; mRNA Stability; molecular mass; mutant; neoplastic cell; novel; protein expression; public health relevance; time interval; tumor; tumorigenesis

DESCRIPTION (provided by applicant): Phospholipids and lysophospholipids are known to act as lipid mitogens that regulate cell proliferation and survival signaling pathways. The levels of these lipids are tightly regulated by their respective lipases and thus, the expression and activity of these enzymes is critical for cellular homeostasis. We have cloned a cDNA that encodes a novel putative lysophospholipase. In view of its predicted molecular mass of 34 kDa, we have named it LPL34 (Lysophospholipase 34). Preliminary results suggest that LPL34 contains lipase activity. Our preliminary results also show that LPL34 mRNA is highly expressed in normal colon mucosa but absent or reduced in established colon cancer cell lines. LPL34 mRNA expression is also lost or reduced in 63% (24/38) of primary colon cancers when compared to their matching normal tissues. Using purified LPL34 protein, we have generated two high quality LPL34 antibodies. Western blot and immunohistochemistry analyses using these antibodies demonstrate that LPL34 protein expression is also significantly reduced in all primary colon tumors tested. Consistent with these results, expression of exogenous LPL34 in cancer cells lacking endogenous LPL34 results in growth inhibition suggesting that LPL34 appears to be a novel tumor suppressor. To investigate the relevance of LPL34 alterations in colon tumoriogenesis, we will examine LPL34 protein expression status in matching primary colon normal and tumor specimens and correlate LPL34 expression with various clinicapathological parameters. The molecular mechanism(s) responsible for LPL34 down-regulation in colon tumor will be investigated and the role of lipase activity of LPL34 in cellular growth suppression will also be determined. To further understand the physiological function(s) of LPL34 in cell growth control, we will initiate studies to identify and study its potential lipid substrates and interacting proteins. To delineate the role of LPL34 in the GI malignancies, we propose to generate inducible conditional deletion of LPL34 in the GI tract of transgenic mice. The outcome of these studies will provide important information about (1) the value of LPL34 as diagnostic/prognostic marker, (2) the molecular mechanism(s) of action of this novel lysophospholipase in normal cell growth and (3) its contribution in colon cancer development. PUBLIC HEALTH RELEVANCE: Phospholipids and lysophospholipids are known to act as lipid mitogens that regulate cell proliferation and survival signaling pathways. The levels of these lipids are tightly regulated by their respective lipases and thus, the expression and activity of these enzymes is critical for cellular homeostasis. We have cloned a cDNA that encodes a novel putative lysophospohlipase, named LPL34. Our preliminary results suggest that LPL34 contains lipase activity and may be involved in colon cancer development. We have proposed three specific aims to study this novel lysophospholipase. The outcome of these studies will provide important information about (1) the value of LPL34 as diagnostic/prognostic marker, (2) the molecular mechanism(s) of action of this novel lysophospholipase in normal cell growth and (3) its contribution in colon cancer development.

描述(申请人提供)：磷脂和溶血磷脂被认为是调节细胞增殖和生存信号通路的脂质有丝分裂原。这些脂类的水平受到它们各自的脂肪酶的严格调控，因此，这些酶的表达和活性对细胞内环境的稳定至关重要。我们克隆了一个编码一种新的溶血磷脂酶的基因。鉴于其预测的分子质量为34 kDa，我们将其命名为LPL34(溶血磷脂酶34)。初步结果表明，LPL34具有脂肪酶活性。我们的初步结果还表明，LPL34mRNA在正常结肠粘膜中高表达，但在已建立的结肠癌细胞系中缺失或减少。与其匹配的正常组织相比，63%(24/38)的原发性结肠癌组织中LPL34mRNA的表达也丢失或降低。利用纯化的LPL34蛋白，我们已经产生了两种高质量的LPL34抗体。用这些抗体进行的Western印迹和免疫组织化学分析表明，在所有被测试的原发结肠肿瘤中，LPL34蛋白的表达也显著降低。与这些结果一致的是，在缺乏内源性LPL34的癌细胞中表达外源LPL34会导致生长抑制，这表明LPL34似乎是一种新的肿瘤抑制因子。为了探讨LPL34基因突变在结肠肿瘤发生中的作用，我们将检测LPL34蛋白在配对的正常结肠组织和肿瘤组织中的表达情况，并将其与不同的临床病理参数相关联。我们将研究LPL34在结肠癌中下调的分子机制(S)，以及LPL34的脂肪酶活性在细胞生长抑制中的作用。为了进一步了解LPL34在细胞生长控制中的生理功能(S)，我们将启动对其潜在脂底物和相互作用蛋白的鉴定和研究。为了阐明LPL34在胃肠道恶性肿瘤中的作用，我们建议在转基因小鼠的胃肠道中产生可诱导的条件缺失LPL34。这些研究的结果将为(1)LPL34作为诊断/预后标志物的价值，(2)这种新的溶血磷脂酶在正常细胞生长中作用的分子机制(S)以及(3)它在结肠癌发生中的作用提供重要的信息。 公共卫生相关性：磷脂和溶血磷脂被认为是调节细胞增殖和生存信号通路的脂质有丝分裂原。这些脂类的水平受到它们各自的脂肪酶的严格调控，因此，这些酶的表达和活性对细胞内环境的稳定至关重要。我们克隆了一个编码一种新的溶血磷脂酶的基因，命名为LPL34。我们的初步结果表明，LPL34含有脂肪酶活性，可能与结肠癌的发生有关。我们提出了三个特定的目标来研究这种新的溶血磷脂酶。这些研究的结果将为(1)LPL34作为诊断/预后标志物的价值，(2)这种新的溶血磷脂酶在正常细胞生长中作用的分子机制(S)以及(3)它在结肠癌发生中的作用提供重要的信息。