HOXA11调控腹膜间皮细胞间质转化促进胃癌腹膜转移的机制研究

Peritoneal metastasis is an important prognostic factor for gastric cancer patients. Recently, mesothelial to mesenchymal transition (MMT) in peritoneal microenvironment was found participating in peritoneal metastasis of cancer. In our previous works, differential expression genes among primary lesion of gastric cancer, peritoneal metastases and precancerous gastric mucosa were detected by whole transcriptome sequencing, and found that expression of HOXA11 was related with gastric cancer peritoneal metastasis. In HOXA11 positive peritoneal metastases, MMT of mesothelial cells was confirmed. The aim of present study is to investigated the function and molecular mechanisms of HOXA11 in gastric cancer peritoneal metastasis. The detail working schedule includes: 1) Clinical phenomena observation: to confirm the correlation of HOXA11 with gastric cancer peritoneal metastasis and MMT by detecting tissue samples collected form gastric cancer patients with peritoneal metastasis; 2) Biological function study: to clarify the impacts of HOXA11 on capability of peritoneal metastasis of gastric cancer cells by changing HOXA11 level in gastric cancer cells, and its ability to induce MMT of mesothelial cells by co-culturing primary peritoneal mesothelial cells with gastric cancer cells with different HOXA11 expression; 3) Molecular mechanism investigation: to elucidate the impact of HOXA11 on MMT of mesothelial cells by regulating promoter transcription and expression of IL-11.

腹膜转移是影响胃癌患者预后的重要因素，腹膜微环境中的间皮细胞间质转化（Mesothelial to mesenchymal transition，MMT）可参与促进肿瘤腹膜转移。本课题组前期通过高通量检测比较胃癌原发灶、腹膜转移灶及癌旁非肿瘤胃粘膜中差异表达基因，发现HOXA11表达与胃癌腹膜转移相关，并在HOXA11阳性转移灶中证实腹膜间皮细胞MMT现象。本课题旨在从三个层次（现象-功能-机制）、两个角度（肿瘤-宿主），明确HOXA11通过调控MMT促进腹膜转移的作用及其分子机制，为胃癌腹膜转移及分子干预策略提供信息。研究内容包括：1）现象观察：HOXA11与胃癌腹膜转移及MMT的关系；2）生物学功能研究：HOXA11调控胃癌细胞腹膜转移能力，并诱导腹膜间皮细胞发生MMT；3）分子机制探索：HOXA11通过转录调控IL-11表达，诱导间皮细胞MMT而促进胃癌腹膜转移。

腹腔是胃癌最常见转移部位之一。形成腹膜转移灶的播散胃癌细胞与癌旁胃粘膜上皮细胞甚至原发灶胃癌细胞存在异质性表现。理解并探索这种异质性及其生物学意义需要全新的理论依据和实验技术支持，检测并分析胃癌腹膜转移灶的基因表达谱有助于筛选并鉴定腹膜转移关键驱动基因，为胃癌腹膜转移治疗提供更为精准的治疗靶点和探索全新的治疗策略。. 通过高通量检测比较胃癌原发灶、腹膜转移灶及癌旁非肿瘤胃粘膜中差异表达基因，发现Homeobox A11 （HOXA11）表达与胃癌腹膜转移相关，并在HOXA11阳性转移灶中证实腹膜间皮细胞Mesothelial to mesenchymal transition （MMT）现象。临床组织标本包括癌旁胃粘膜组织、胃癌原发灶及转移灶（腹膜及非腹膜转移灶），检测HOXA11基因mRNA及蛋白表达，分析HOXA11与胃癌腹膜转移的相关性及特异性。在体外实验中，观察并比较HOXA11上调或下调后，胃癌细胞干性、侵袭、转移能力变化，包括失巢凋亡、迁移、侵袭、凋亡、微球形成能力以及与间皮细胞粘附等。利用裸鼠建立胃癌细胞腹腔种植瘤模型，通过体内实验观察HOXA11不同表达的胃癌细胞，其腹腔种植及形成腹膜转移灶的能力。. 本研究筛选并验证了胃癌原发灶和腹膜转移灶中高表达的HOXA11促进胃癌细胞腹腔种植瘤形成能力，结果提示HOXA11可能成为胃癌患者发生腹膜转移的关键驱动基因，未其成为胃癌腹膜转移治疗靶点潜在临床转化价值有待进一步探索。