Blocking IGF1R gene makes prostate cancer cells vulnerable

British researchers said on Friday that blocking the action of the IGF1R gene can make prostate cancer cells more sensitive to radiotherapy and certain kinds of chemotherapy.

To achieve blockade, the team, at the Weatherall Institute of Molecular Medicine in Oxford, used RNA interference which has the unique ability to switch off a single one of a cell’s 35,000 genes.The findings, published in Cancer Gene Therapy, show that switching off IGF1R in a selection of prostate cancer cells resistant to different treatments makes the cells twice as sensitive to radiotherapy. Also, researcher Dr Val Macaulay said, “blocking the IGF1R gene enhanced the effect of chemotherapy on hormone independent prostate cancer cells, so this technique could be effective against prostate cancers that are resistant to hormone-based therapy.” The technique made the cells significantly more sensitive to drugs that kill cells by damaging their DNA–mitoxantrone, etoposide and nitrogen mustard–but did not enhance the effect of those that kill without causing DNA damage–paclitaxel and 5-fluorouracil. Dr Macaulay added in a statement that the results suggest that IGF1R plays a role in the cell’s response to DNA damage, and will indicate which type of agents are likely to be enhanced by treatments targeting the gene. “As an oncologist,” he added, “I am excited at the possibility of conducting trials of IGF1R-inhibiting drugs with my own patients.” (Source: Cancer Gene Ther 2004:11: Reuters Health: Richard Woodman: Oncolink: October 2004.)