Lal A, Peters H, St Croix B, Haroon Z A, Dewhirst M W, Strausberg R L, Kaanders J H, van der Kogel A J, Riggins G J
Department of Pathology, Duke University Medical Center, Durham, NC 27710, USA.
J Natl Cancer Inst. 2001 Sep 5;93(17):1337-43. doi: 10.1093/jnci/93.17.1337.
The presence of hypoxic regions within solid tumors is associated with a more malignant tumor phenotype and worse prognosis. To obtain a blood supply and protect against cellular damage and death, oxygen-deprived cells in tumors alter gene expression, resulting in resistance to therapy. To investigate the mechanisms by which cancer cells adapt to hypoxia, we looked for novel hypoxia-induced genes.
The transcriptional response to hypoxia in human glioblastoma cells was quantified with the use of serial analysis of gene expression. The time course of gene expression in response to hypoxia in a panel of various human tumor cell lines was measured by real-time polymerase chain reaction. Hypoxic regions of human carcinomas were chemically marked with pimonidazole. Immunohistochemistry and in situ hybridization were used to examine gene expression in the tumor's hypoxic regions.
From the 24 504 unique transcripts expressed, 10 new hypoxia-regulated genes were detected-all induced, to a greater extent than vascular endothelial growth factor, a hypoxia-induced mitogen that promotes blood vessel growth. These genes also responded to hypoxia in breast and colon cancer cells and were activated by hypoxia-inducible factor 1, a key regulator of hypoxic responses. In tumors, gene expression was limited to hypoxic regions. Induced genes included hexabrachion (an extracellular matrix glycoprotein), stanniocalcin 1 (a calcium homeostasis protein), and an angiopoietin-related gene.
We have identified the genes that are transcriptionally activated within hypoxic malignant cells, a crucial first step in understanding the complex interactions driving hypoxia response. Within our catalogue of hypoxia-responsive genes are novel candidates for hypoxia-driven angiogenesis.
实体瘤内缺氧区域的存在与更恶性的肿瘤表型及更差的预后相关。为了获得血液供应并防止细胞损伤和死亡，肿瘤中缺氧的细胞会改变基因表达，从而产生对治疗的抗性。为了研究癌细胞适应缺氧的机制，我们寻找新的缺氧诱导基因。
利用基因表达序列分析对人胶质母细胞瘤细胞中缺氧的转录反应进行定量。通过实时聚合酶链反应测量一组不同人类肿瘤细胞系中对缺氧反应的基因表达时间进程。用匹莫硝唑对人癌的缺氧区域进行化学标记。采用免疫组织化学和原位杂交检测肿瘤缺氧区域的基因表达。
从所表达的24504个独特转录本中，检测到10个新的缺氧调节基因——所有这些基因的诱导程度均大于血管内皮生长因子，血管内皮生长因子是一种促进血管生长的缺氧诱导有丝分裂原。这些基因在乳腺癌和结肠癌细胞中也对缺氧有反应，并被缺氧诱导因子1激活，缺氧诱导因子1是缺氧反应的关键调节因子。在肿瘤中，基因表达仅限于缺氧区域。诱导基因包括六臂蛋白（一种细胞外基质糖蛋白）、鲟钙蛋白1（一种钙稳态蛋白）和一个血管生成素相关基因。
我们已经鉴定出在缺氧恶性细胞中转录激活的基因，这是理解驱动缺氧反应的复杂相互作用的关键的第一步。在我们的缺氧反应基因目录中，有缺氧驱动血管生成的新候选基因。
