ABSTRACT
The carotenoid lycopene, found in tomatoes, has been associated with decreasing prostate cancer risk. Potential mechanisms for this risk reduction include lycopene’s status as a potent antioxidant, its inhibitory effect on cell proliferation and its ability to increase intercellular gap junctional communication. Presently, in the United States, almost 200,000 men are diagnosed with the disease and approximately 30,000 succumb to its metastatic effects. Therefore, novel treatment strategies are needed for patients who currently have the disease, especially those in advanced, i.e., metastatic status. We sought to determine whether lycopene’s inhibitory properties on pre-malignancy could be extended to advanced prostate cancer by assessing effects on a cell line derived through metastatic passage, the PC-3MM2. To our surprise, we found that in this cell line, lycopene has a potentially unwanted effect of up-regulating expression of the uPAR and facilitating invasion while failing to significantly inhibit proliferation or to induce detectable levels of the gap junctional protein connexin 43 expression. These results indicate that some caution should be used with regard to use of lycopene to treat potentially advanced and metastatic prostate cancers.
