HOXB7调控Src/FAK信号通路对胃癌生物学行为的影响及机制研究

Homeobox B gene family (HOXB) molecules play a crucial role in the growth and differentiation of cell. Recently, more and more researches concerning HOXB were reported in different tumors. Some researchers suggested that HOXB family had a wide application prospects as an emerging field in terms of the diagnosis and treatment in malignant tumors. HOXB7 was an important member of HOXB family, and its role in gastric cancer was still unclear. It has been reported that Src/FAK signal pathway could promote the development of EMT by regulating the expression of E-cadherin. However, the role of Src/FAK signal pathway in gastric cancer was still not clear.Our previous experimental results showed that the expression of HOXB7 in gastric cancer tissues was significantly higher than that of paired normal tissues, and the expression of HOXB7 could promote growth and invasion of gastric cancer cell. Our preliminary results showed that HOXB7 was related to Src/FAK signal pathway. We hypothesized that HOXB7 could promote invasion and metastasis of gastric cancer cells by regulating Src/FAK signal pathway. We will carry out a series of experiments including siRNA inference, quantitative PCR, western blotting,immunohistochemistry and so on to verify the following objectives in the integral level of cell, animal, and clinical tissue specimens: HOXB7 could regulate the expression of Src/FAK signal pathway; HOXB7 played an improtant part in promoting the EMT and metastasis of gastric cancer; HOXB7 could promote EMT and metastasis of gastric cancer cell by regulating Src/FAK signal pathway.In all, the objective of this study was to provide theoretical basis for the prevention and therapeutic of gastric cancer.

近来，有关HOXB家族分子在不同肿瘤中的报道越来越多。有学者认为，HOXB家族在恶性肿瘤诊治方面有广阔的应用前景。HOXB7是HOXB家族中的重要一员，在胃癌中的作用不明确。此外，Src/FAK信号通路在部分肿瘤的上皮间质化中发挥着重要作用，而在胃癌中的作用不详。我们的前期实验结果显示，HOXB7在胃癌组织中的高表达、能促进胃癌细胞的增殖及侵袭、HOXB7和Src/FAK信号通路有关联。鉴于以上研究背景，本课题假设HOXB7通过调控Src/FAK信号通路诱导胃癌上皮间质化的发生，从而促进胃癌侵袭、转移。在前期研究的基础上，我们将通过siRNA干扰、定量PCR、免疫印迹等方法，从细胞、动物、临床样本多方面整体水平来验证HOXB7在胃癌上皮间质化及侵袭、转移中的重要作用，明确HOXB7对Src/FAK信号通路调控的作用机制，从而为揭示胃癌侵袭、转移的发生机制奠定基础，为防治胃癌的转移提供思路。

同源异型盒基因家族是一个编码转录因子蛋白的基因大家族。近年来，随着同源异型盒基因家族（Homeobox gene family）分子在不同肿瘤中的报告越来越多，其与肿瘤侵袭、转移关系的研究成为热点。HOXB7是HOXB家族中的重要一员，在胃癌中的作用不明确。我们的前期实验结果显示，HOXB7在胃癌组织中的高表达、能促进胃癌细胞的增殖及侵袭、HOXB7和Src/FAK信号通路有关联。鉴于前期的工作基础，本课题假设HOXB7通过调控Src/FAK信号通路诱导胃癌上皮间质化的发生，从而促进胃癌侵袭、转移。我们将通过siRNA干扰、定量PCR、免疫印迹等方法，从细胞、动物、临床样本多方面整体水平来验证HOXB7在胃癌侵袭、转移中的重要作用，并明确HOXB7对Src/FAK信号通路调控的作用机制。具体的研究的内容有：测定胃癌组织标本中HOXB7 的表达及临床意义；体外实验评估HOXB7 对胃癌细胞生物学行为的影响，体内试验评估HOXB7 对胃癌的发生、发展的影响；HOXB7对 Src/FAK 信号通路的调控及机制研究；HOXB7 在胃癌上皮间质化中的作用及机制。研究发现，癌组织的HOXB7mRNA表达明显高于癌旁组织，HOXB7mRNA在癌组织中的表达为0.005881±0.006694，癌旁组织中的表达为0.001885±0.008110。通过免疫组化测定了HOXB7在癌及癌旁组织中的表达情况，研究发现在癌组织中HOXB7的阳性率为76.2%，高于癌旁组织中的10.7%。通过SPSS方法统计HOXB7表达与患者临床病理及预后的关系，发现HOXB7的高表达与浸润深度、淋巴结转移及病理分期呈现正相关；HOXB7高表达的患者预后较差。多因素预后分析发现，HOXB7表达结果及病理分期是影响胃癌预后的独立因素。进一步测定了HOXB7在胃癌细胞株中的表达，及HOXB7表达对胃癌细胞增殖、侵袭、迁移、凋亡等功能的影响。实验结果表明，HOXB7能促进胃癌细胞的增殖、促进侵袭、转移。HOXB7表达与N-cadherin显著正相关，与E-cadherin负相关，表明HOXB7的表达与胃癌上皮间质化有关。进一步的机制研究发现，HOXB7通过激活Src/FAK信号通路来促进胃癌的侵袭、转移。本研究的重要意义在于，为揭示胃癌侵袭、转移的发生机制奠定基础，为防治胃癌的转移提供思路。