The commonly used psychotropic drug Prozac (fluoxetine) is no longer meant only for treating depression. Tel Aviv University researchers have found that Prozac can fight the resistance of cancer cells to a major Israeli-developed tumor-fighting drug. Dr. Dan Peer and colleagues at the department of cell research and immunology have shown that Prozac dramatically enhances the effectiveness of a widely used anti-cancer drug doxorubicin. Called Doxil in a reformulated, more effective version in which the active ingredient was placed in a fat bubble called a liposome, the chemotherapy drug was developed by Prof. Yechezkel Barenholz of the Hebrew University of Jerusalem and Shaare Zedek Medical Center oncologist Prof. Alberto Gabizon. The approved drug is widely used to treat ovarian and breast cancer and currently is in the process of being approved for other types cancer. "The good news is that the medical community won't have to wait," said Peer. Prozac is a well-tested medication that can be used for this purpose right away, he continued, noting that US doctors already prescribe it to treat depression in chemotherapy patients. "Prozac is a very interesting non-specific blocker of cancer resistance," said Peer, whose study focused on colon cancer and doxorubicin. In their laboratory experiments, the TAU scientists led by graduate student Mirit Argov together with Prof. Rimona Margalit, found that Prozac enhanced doxorubicin's efficacy more than 1,000%. Prozac, in effect, worked to block the cancer drug from leaving the interior of the cancer cell and poisoning the healthy non-cancerous cells that surrounded it. In animal models, a mild doxorubicin-fluoxetine treatment combination significantly slowed down tumor progression. These results suggest that pairing Prozac with chemotherapeutic drugs to curb drug resistance warrants further clinical study. Peer's research was just published in Cancer Letters, and his suggestions are now listed as recommendations in the latest version of Cancer Encyclopedia. "Working with a major drug developer, we have validated Prozac's potential, and now Tel Aviv University can lead a humanitarian effort to save lives around the globe," he stressed. Since it is very hard to protect this patent because any clinician can prescribe Prozac, it is impossible for TAU to commercialize its research, he added. Instead, he suggests that researchers join forces internationally to implement retrospective studies of all the types of cancer treatment in which Prozac was prescribed. And further clinical experiments to validate the use of Prozac with chemotherapy is also needed, Peer said. "The next step is to take the files of chemo patients and determine whether they received Prozac for their depression," says Peer. "This will streamline the understanding in the scientific community of whether, how and for which cancer-fighting drugs Prozac can be an effective partner. It will also give us invaluable information on how to design new drugs." His lab is also developing several new drug delivery nanotechnologies to bring novel therapeutics into breast, blood, pancreatic and brain cancers. A recent technological breakthrough to reprogram immune cells involved in ulcerative colitis and Crohn's disease was reported in Science earlier this year and is the basis of a new platform technology developed by his group.