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【medical-news】Muscle protein myosin VI involved in the de
Medical Research News
Published: Wednesday, 8-Nov-2006
Researchers at the Johns Hopkins Kimmel Cancer Center have for the first time implicated the muscle protein myosin VI in the development of prostate cancer and its spread.
In a series of lab studies with human prostate cancer cells, the Hopkins scientists were surprised to find overproduction of myosin VI in both prostate tumor cells and precancerous lesions. When the scientists genetically altered the cells to "silence" myosin VI, they discovered the cells were less able to invade in a test tube.
"Our results suggest that myosin VI may be critical in starting and maintaining the malignant properties of the majority of human prostate cancers diagnosed today," says Angelo M. De Marzo, M.D., Ph.D., a study coauthor and associate professor of pathology, urology and oncology.
The Hopkins work, published in the November issue of the American Journal of Pathology, has potential value for better ways to diagnose the disease, treat and track the effects of drugs and surgery. "Targeting myosin VI represents a promising new approach that could lead eventually new approaches to treating the disease," says Jun Luo, Ph.D., senior author of the paper and assistant professor of urology.
Myosins are a class of 40 motor proteins that power cell movement and muscle contractions. Normally, as they work, myosins slide in a single direction along the threads of a protein called actin. But myosin VI moves against the grain, and it does not function as a classical "muscle" protein.
Using a DNA microarray to study all of the genes in 59 samples of benign or cancerous prostate tissue from patients at Johns Hopkins, the researchers found the malignant samples showed a 3.7-fold higher expression of myosin VI as compared to normal samples, and a 4.6-fold increase as compared to the samples from patients with enlarged prostate.
Next, the researchers hunted for myosin VI in 240 prostate tissue samples, discovering overproduction early in the development of prostate cancer in such pre-tumor conditions as high-grade prostatic intraepithelial neoplasia (PIN) and proliferative inflammatory atrophy.
Finally, when they altered some cancerous cells by knocking down their myosin VI protein, the cancer cells not only were less able to spread around, but also showed 10 times the amount of a tumor suppressor called thioredoxin-interacting protein (TXNIP).
Prostate cancer, which affects one in nine American men over the course of their lives, is mainly diagnosed by needle biopsy of the prostate gland after a blood test shows an increased level of prostate-specific antigen (PSA). While the PSA test is now widespread and provides many men with early diagnosis and better chance of a cure, says Luo, it may not be sensitive or specific enough to pinpoint the existence of cancer. Using myosin VI or other factors, it may be possible, Luo says, to create a laboratory test to identify high or low levels in urine or blood samples, and this might aid in the detection of prostate cancer. Myosin VI also has been shown to be associated with ovarian cancer. 本人认领这篇，48小时未交稿，其他战友自由认领 肌球蛋白与前列腺癌的发生有关
2006年十一月份发布的医学研究新闻
约翰霍谱金森大学Kimmel癌症研究中心的研究者们首次提出肌肉的肌球蛋白VI与前列腺癌的发生与转移有关。
霍谱金森大学的科学家在对前列腺癌细胞进行一系列的实验室研究发现，肌球蛋白VI无论是在前列腺的瘤细胞还是在癌前病变组织都是过量的。当科学家们利用遗传学的手段使肌球蛋白VI“沉默”，他们发现瘤细胞在试管里的侵袭性下降了。
该项研究的合作者与参加着病理学教授，泌尿学和肿瘤医学博士Angelo M. De Marzo说道：“我们的结果表明在人们所诊断的前列腺癌中，肌球蛋白VI也许是在启动与维持恶性肿瘤的的关键因素。
发表在十一月份美国病理学杂志上霍谱金森大学的这项成果使的有潜在的价值去更好的诊断疾病，并且可以可以评估手术与药物的效果。这篇论文的高级作者泌尿学助理教授Jun Luo博士说道：“针对肌球蛋白VI的治疗代表了一种可以最终治疗这种疾病的新途径。
肌球蛋白是一类包括40多种供细胞运动与收缩的动力蛋白。在正常情况下肌球蛋白沿着肌动蛋白在一个方向滑动。但是在肌球蛋白VI反方向移动时，这时没有功能时被分为“肌肉蛋白”一类。
约翰霍谱金森大学通过DNA微点阵技术分析了59个从前列腺癌患者取的样品的所有基因发现在恶性样品中肌球蛋白VI的含量是正常样品的3.7倍，是前列腺增大患者的4.6倍。
下一步，研究者收集了240个前列腺组织样品的肌球蛋白VI，发现在前列腺癌中诸如癌前病变的情况，前列腺高度上皮瘤样变增生与炎性萎缩时肌球蛋白VI超量。
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作者:admin@医学,生命科学 2010-10-22 22:06
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