Study sheds light on how cancer spreads in blood 研究揭示了癌症如何在血液中擴散

News Release 9-Jul-2020

Comment: Oh, my. It seems that cancer progression promoters that help cancer metastasis may have something to do with palmitoylated proteins. Protein Palmitoylation is a reaction that links palmitic acid through a covalent bond to a cysteine residue on a protein. If we can stop palmitoylation, then there will be no palmitoylated proteins and thus cancer progression will slow down. We can not eliminate proteins which we need, but we may take palmitic acid – a saturated fatty acid found in most cases in animal derived foods. That makes sense. We have known that animal fat promote cancer develops and cancer patients who use animal foods have a poorer prognosis. So what you can do to prevent cancer or treat cancer? Take palmitic acid out of your diet. Unfortunately, palm oil which is full of palmitic acid is very commonly used in processed foods to replace trans fat. So will need also to avoid eating processed foods. If you want to know a bit about what palmitic acid can do to hurt you, read this article.

Animal fat from beef, pork and chicken and palm oil contain high amounts of palmitic acid (>20%). But some plant derived oils contain fairly high amounts of palmitic acid too including wheat germ oil, rice bran oil, olive oil. Coconut oil does not contain palmitic acid while rapeseed oil contains a relatively lower amount (4%).

評論：哦，我的天哪。似乎有助於癌症轉移的癌症進展啟動子可能與棕櫚酰化蛋白有關。蛋白質棕櫚酰化是通過共價鍵將棕櫚酸與蛋白質上的半胱氨酸殘基連接的反應。如果我們能夠停止棕櫚酰化，那麼將沒有棕櫚酰化的蛋白質，因此癌症的進展將會減慢。我們無法消除需要的蛋白質，但我們能夠避免吃棕櫚酸-一種在大多數情況下在動物衍生食品中發現的飽和脂肪酸。這就說得通了。我們知道動物脂肪會促進癌症的發展，並且使用動物性食物的癌症患者的預後較差。那麼如何預防癌症或治療癌症呢？從飲食中取出棕櫚酸。不幸的是，充滿棕櫚酸的棕櫚油非常常用於加工食品中，以代替反式脂肪。因此也將需要避免食用加工食品。

動物脂肪和棕櫚油含有大量的棕櫚酸。但是一些植物衍生油也包含相當大量的棕櫚酸，包括小麥胚芽油，米糠油，橄欖油。椰子油不含棕櫚酸，而菜籽油則相對較低

Analysis of particles shed by tumors points to new, less invasive way to diagnose malignancies

Cedars-Sinai Medical Center

Dolores Di Vizio, Cedars-Sinai (IMAGE)

A new study sheds light on proteins in particles called extracellular vesicles, which are released by tumor cells into the bloodstream and promote the spread of cancer. The findings suggest how a blood test involving these vesicles might be used to diagnose cancer in the future, avoiding the need for invasive surgical biopsies.

The research is a large-scale analysis of what are known as palmitoylated proteins inside extracellular vesicles, according to Dolores Di Vizio, MD, PhD, professor of Surgery, Biomedical Sciences and Pathology and Laboratory Medicine at Cedars-Sinai. Di Vizio is co-corresponding author of the study, published online June 10 in the Journal of Extracellular Vesicles.

Extracellular vesicles have gained significant attention in the last decade because they contain proteins and other biologically important molecules whose information can be transferred from cell to cell. They are known to help cancer metastasize to distant sites in the body, but exactly how this happens is not clear.

To learn more about this process, the research team looked into a process called palmitoylation, in which enzymes transfer lipid molecules onto proteins. Palmitoylation can affect where proteins are located within cells, their activities and their contribution to cancer progression.

The investigators examined two types of extracellular vesicles, small and large, in samples of human prostate cancer cells. Using centrifuges, they separated the extracellular vesicles from the other cell materials and analyzed the levels of palmitoylation and the types of proteins present.

The team found extracellular vesicles derived from the cancer cells contained palmitoylated proteins that are associated with the spread of cancer. Further, when the team chemically suppressed the palmitoylation process, the level of some of these proteins went down in the extracellular vesicles.

“Our results suggest that protein palmitoylation may be involved in the selective packaging of proteins to different extracellular vesicle populations in the body,” Di Vizio said. “This finding raises the possibility that by examining these proteins in extracellular vesicles in the bloodstream, we may be able to detect and characterize cancer in a patient in the future without performing a surgical biopsy.”

Di Vizio said the next step in the research is to conduct a study in collaboration with her Cedars-Sinai colleagues and industry partners that will use advanced technologies, including mass spectrometry and flow cytometry, with the goal of identifying clinically significant prostate cancer at diagnosis. 

In addition to Di Vizio, Wei Yang, PhD, associate professor of Surgery at Cedars-Sinai, and Andries Zijlstra, PhD, are co-corresponding authors for the study. Zijlstra completed the research while working at Vanderbilt University Medical Center in Nashville. Javier Mariscal, PhD, a postdoctoral scientist in Di Vizio’s laboratory, is the study’s first author.

Funding: Research reported in this publication was supported by the National Institutes of Health under award number R01CA218526 and by the U.S. Department of Defense.

DOI: 10.1080/20013078.2020.1764192