Genes and their level of expression is important in cells. It is what gives a particular cell its unique qualities. Different levels of different genes are expressed in cells in the liver compared with those in the lung, for example. In cancer, the amount of gene expression is frequently altered, resulting in either increased concentrations (overexpression) or not quite enough (underexpression). Such alterations could lead to aberrant growth or even to resistance to current cancer chemotherapy.
Increasing evidence has been accumulating that implicate an RNA binding protein, called HuR, in the development of chemotherapeutic resistance. Several papers in the past few years have shown that increased amounts of HuR, along with where the protein in located in the cell, can dramatically alter how a cancer cell responds to therapy. In pancreatic cancer cells, increased HuR levels in the cytoplasm of the cell significantly aids in the response to gemcitabine, the current chemotherapy for pancreatic cancer. In breast cancer, and now in glioma cells, increased HuR levels increases the resistance to currently used chemotherapy including tamoxifen, etoposide, cisplatin and topotecan.
While this data is still in the preclinical stages, and much more needs to be done before it can be used in the clinic, it still offers new insights into how resistance develops in cancer. RNA binding proteins are not particularly well studied compared with other proteins and microRNAs. It is exciting to see a slow and steady progression in this field.
Natalia Filippova et. al.
Molecular Cancer Research 9:648-659
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