Selvakumar Ponniah, Pasha Mohammed Khysar, Ashakumary Lakshmikuttyamma, Dimmock Jonathan R, Sharma Rajendra K
Department of Pathology and Cancer Research Unit, College of Medicine and Saskatchewan Cancer Agency, Saskatoon, SK, Canada.
Int J Mol Med. 2002 Oct;10(4):493-500.
Colorectal cancer is the second leading cause of malignant death, and better preventive strategies are needed. The treatment of colonic cancer remains difficult because of the lack of effective chemotherapeutic agents; therefore it is important to continue to search for cellular functions that can be disrupted by chemotherapeutic drugs resulting in the inhibition of the development and progression of cancer. The current knowledge of the modification of proteins by myristoylation involving myristoyl-CoA:protein N-myristoyltransferase (NMT) is in its infancy. This process is involved in the pathogenesis of cancer. We have reported for the first time in rats treated with azoxymethane that NMT activity was higher in colonic epithelial neoplasms than in normal colonic tissue and that an increase in NMT activity appeared at an early stage in colonic carcinogenesis. Increased NMT activity was also confirmed in human colonic tumors compared to normal tissue. Furthermore, colorectal tumors displayed increased immunohistochemical staining for NMT compared to normal mucosa in the cytoplasm. In addition, gallbladder carcinoma showed moderate to strong cytoplasmic positivity for NMT with increased intensity in the invasive component whereas the normal gallbladder mucosa showed weak to negative cytoplasmic staining for this enzyme. It is conceivable therefore that NMT can be used as a potential marker for the early detection of cancer. Of particular note is the very recent discovery of cytotoxic compounds in the laboratories of the authors which inhibit NMT and may offer a novel approach for the evolution of candidate antineoplastic agents which display greater potencies towards neoplasms than the corresponding normal tissues.
结直肠癌是恶性死亡的第二大主要原因,因此需要更好的预防策略。由于缺乏有效的化疗药物,结肠癌的治疗仍然困难;因此,继续寻找可被化疗药物破坏的细胞功能,从而抑制癌症的发展和进展非常重要。目前关于肉豆蔻酰化修饰蛋白质(涉及肉豆蔻酰辅酶A:蛋白质N-肉豆蔻酰转移酶(NMT))的知识尚处于起步阶段。这一过程与癌症的发病机制有关。我们首次在接受氧化偶氮甲烷处理的大鼠中发现,结肠上皮肿瘤中的NMT活性高于正常结肠组织,并且在结肠癌发生的早期阶段NMT活性就出现了增加。与正常组织相比,人类结肠肿瘤中也证实了NMT活性增加。此外,与正常黏膜相比,结直肠肿瘤在细胞质中NMT的免疫组织化学染色增加。此外,胆囊癌显示NMT在细胞质中呈中度至强阳性,在浸润成分中强度增加,而正常胆囊黏膜对该酶的细胞质染色呈弱阳性至阴性。因此,可以想象NMT可作为癌症早期检测的潜在标志物。特别值得注意的是,作者实验室最近发现了抑制NMT的细胞毒性化合物,这可能为开发候选抗肿瘤药物提供一种新方法,这些药物对肿瘤的效力比对相应正常组织的效力更大。