Ververis Katherine, Karagiannis Tom C
Am J Transl Res. 2012;4(1):24-43. Epub 2012 Jan 5.
The histone deacetylase inhibitors, suberoylanilide hydroxamic acid (Vorinostat, Zolinza™) and depsipeptide (Romidepsin, Istodax™) have been approved by the US Food and Drug Administration for the treatment of refractory cutaneous T-cell lymphoma. Numerous histone deacetylase inhibitors are currently undergoing clinical trials, predominantly in combination with other cancer modalities, for the treatment of various haematological and solid malignancies. Most of the traditional compounds are known as broad-spectrum or pan-histone deacetylase inhibitors, possessing activity against a number of the 11 metal-dependent enzymes. One of the main questions in the field is whether class- or isoform-specific compounds would offer a therapeutic benefit compared to broad-spectrum inhibitors. Therefore, analysis of the relative expression of the different histone deacetylase enzymes in cancer cells and tissues is important to determine whether there are specific targets. We used a panel of antibodies directed against the 11 known mammalian histone deacetylases to determine expression levels in MCF7 breast cancer cells and in tissue representative of invasive ductal cell carcinoma and ductal carcinoma in situ. Firstly, we utilized a semi-quantitative method based on immunofluorescence staining to examine expression of the different histone deacetylases in MCF7 cells. Our findings indicate high expression levels of HDAC1, 3 and 6 in accordance with findings from others using RT-PCR and immunoblotting. Following validation of our approach we examined the expression of the different isoforms in representative control and breast cancer tissue. In general, our findings indicate higher expression of class I histone deacetylases compared to class II enzymes in breast cancer tissue. Analysis of individual cancer cells in the same tissue indicated marked heterogeneity in the expression of most class I enzymes indicating potential complications with the use of class- or isoform-specific compounds. Overall, our approach can be utilized to rapidly compare, in an unbiased semi-quantitative manner, the differential levels of expression of histone deacetylase enzymes in cells and tissues using widely available imaging software. It is anticipated that such analysis will become increasingly important as class- or isoform-specific histone deacetylase inhibitors become more readily available.
组蛋白脱乙酰酶抑制剂，如辛二酰苯胺异羟肟酸（伏立诺他，Zolinza™）和缩肽（罗米地辛，Istodax™）已获美国食品药品监督管理局批准用于治疗难治性皮肤T细胞淋巴瘤。目前，众多组蛋白脱乙酰酶抑制剂正在进行临床试验，主要是与其他癌症治疗方式联合使用，用于治疗各种血液系统恶性肿瘤和实体瘤。大多数传统化合物被称为广谱或泛组蛋白脱乙酰酶抑制剂，对11种金属依赖性酶中的多种具有活性。该领域的主要问题之一是，与广谱抑制剂相比，针对特定类别或亚型的化合物是否具有治疗优势。因此，分析癌细胞和组织中不同组蛋白脱乙酰酶的相对表达对于确定是否存在特定靶点很重要。我们使用了一组针对11种已知哺乳动物组蛋白脱乙酰酶的抗体，以确定MCF7乳腺癌细胞以及浸润性导管癌和原位导管癌组织样本中的表达水平。首先，我们采用基于免疫荧光染色的半定量方法来检测MCF7细胞中不同组蛋白脱乙酰酶的表达。我们的研究结果表明，HDAC1、3和6的表达水平较高，这与其他使用RT-PCR和免疫印迹法的研究结果一致。在验证了我们的方法后，我们检测了代表性对照组织和乳腺癌组织中不同亚型的表达。总体而言，我们的研究结果表明，与II类酶相比，I类组蛋白脱乙酰酶在乳腺癌组织中的表达更高。对同一组织中单个癌细胞的分析表明，大多数I类酶的表达存在明显异质性，这表明使用针对特定类别或亚型的化合物可能会出现潜在问题。总的来说，我们的方法可用于使用广泛可用的成像软件，以无偏倚的半定量方式快速比较细胞和组织中组蛋白脱乙酰酶的差异表达水平。随着针对特定类别或亚型的组蛋白脱乙酰酶抑制剂越来越容易获得，预计这种分析将变得越来越重要。
