A research team at UCSB, led by Professor Kenneth S. Kosik , has made a significant discovery about the way human stem cells function by studying a set of control genes called microRNA. The paper, published May 1 in Cell, explains the way in which these cells can renew themselves or transform into any type of cell in the human body. The discovery bodes well for cancer research, as tumor stem cells are thought to be responsible for tumor growth, and is expected to help with other diseases and injuries.
Kosik explains in a press release that stem cells have dual properties that allow them to either replicate themselves or transform into any cell type in the body. This ability is known as pluripotency, and Kosik’s team has pinpointed microRNA 145 as nature’s element to control it. “To really understand microRNAs,” Kosik was quoted in a press release, “the first step is to remember the central dogma of biology - DNA is the template for RNA, and RNA is translated to protein.” MicroRNA (miR) is a single-stranded RNA that never goes on to make a protein. Rather, its function is to decrease gene expression.
The UCSB research found that a rise in miR-145 prevents the stem cells’ ability for self-renewal while directing it toward differentiation, which is the process by which a cell changes to a more specialized cell type. When this microRNA is lost, the stem cells are prevented from differentiating.
Kosik told The Independent that some cancers have noticeably decreased levels of miR-145, suggesting that the loss of this element in a cell could cause it to proliferate uncontrollably. Furthermore, each type of cancer has tumor stem cells that have abilities similar to normal stem cells. The hope is that by reintroducing miR-145 as tumor stem cells change into other cell types in the cancer, it could decrease the potential for the tumor to grow.