Metastasis and the ZBP1 Gene

Cancer is a difficult problem to deal with in that there are so many moving molecular parts, the malfunction of only one of which can cause cancer. The previous blog entry noted the importance of a gene known as p18. Its malfunction can lead to breast cancer. Gene In Breast Cancer Pathway Identified, is a Science Daily article with an emphasis on metastasis and its linkage to a gene called ZBP1. Metastasis is a medical term referring to the spread of cancer from one part of the body to another. Quoting from the first paragraph of the article:

Scientists at Albert Einstein College of Medicine of Yeshiva University have discovered how a gene crucial in triggering the spread of breast cancer is turned on and off. The findings could help predict whether breast tumors will metastasize and also reveal potential drug targets for preventing metastasis.

Zipcode binding protein (ZBP1) appears to be active during the embryonic stage of development as it seems to have movement, growth and organization functions that are critical at that point. But in adult tissue the gene is usually not expressed or so it seems. If however, it is expressed in adult tissue then some undesireble results may acrue such as the metastasis of a malignant tumor. Details are at the linked article.

A Gene Called p18 and Breast Cancer

Genetic Cause Of Most Common Form Of Breast Cancer Identified is a Science Daily article whose first paragraph is:

The discovery of tumor-suppressor genes has been key to unlocking the molecular and cellular mechanisms leading to uncontrolled cell proliferation – the hallmark of cancer. Often, these genes will work in concert with others in a complex biochemical system that keeps our cells growing and dividing, disease free.

Researchers at the University of North Carolina at Chapel Hill School of Medicine and UNC Lineberger Comprehensive Cancer Center located a gene known as p18 whose malfunction may lead to cancer. A related paper appears in the May 2009 issue of Cancer Cell.

The gene p18 codes for a braking mechanism and when it is deleted or not expressed cellular replication may proceed unabated. The role of p18 in luminal breast cancers was a specific focus of researchers. Mice are used to test for effective tumor treatments.

Stem Cell Differentiation

Scientists Shed Light On Inner Workings Of Human Embryonic Stem Cells is a Biocompare article with information about the differentiation of embryonic stem cells. Stem cells can be thought of as general template cells having the potential to go in many different directions. The end result of one form of differntiation could be a liver cell. A kidney cell is another possible result. But what process or processes influence stem cell differentiation? That question is in the minds of many researchers including apparently some at UC Santa Barbara who published results of a study they made in the May 1st issue of Cell.

When reading about stem cells the term pluripotency is a useful word with which to become familiarized. It refers to the potential stem cells have of becoming any one of a variety of different cell types. UC researchers cite a reverse approach to learn how pluripotency operates i.e. starting with a skin cell and transforming it back to a stem cell. There are proteins known as transcription factors which enable the pluripotent property of stem cells. By expressing genes that code for these proteins skin cells can revert back to stem cells.

As one of the researchers noted stem cells have the capacity to replicate and produce more of themselves but can also become something other than stem cells. The new finding indicates that a microRNA, dubbed miR-145, decreases the expression of genes coding for three transcription factors which in turn maintains a stem cell state. Evidently as few as three or four genes can control the maintenance of the stem cell state. There is a transcription factor called OCT4 which is able to repress the promoter for miR-145. MicroRNAs regulating the production of transcription factors and themselves being regulated by another transcription factor- the beauty and complexity of gene regulation affecting the differentiation of stem cells.