Prodigiosins as anti cancer agents: living upto their name

Prodigiosins are a family of bright red colored bacterial pigment and derive their name from the miraculous (prodigious) events associated with their occurrence. They indeed seem to be living upto their name as a host of activities such as anti-microbial, anti-malarial, anti-cancer and immunosuppressive have been associated with them. Out of these, immunosuppressive and anti-cancer activity has received more importance as it has a clinical promise. Prodigiosins, isolated mostly from Gram negative bacteria are characterized by a common pyrryldipyrrylmethene structure with varying side chains. The review discusses the mechanisms involved in the anti-cancer activity of this class of compounds. In vitro, prodigiosins have been shown to primarily target the cancer cells independently of the p53 status while little or no effect has been observed on normal cells. In addition, prodigiosins are effective in cancer cells with multidrug resistance phenotype and defects in the apoptotic pathways. These make prodigiosins attractive candidates for further development. Though the molecular targets of prodigiosins have not been clearly defined, they have been found to target different signaling pathways possibly through induction of DNA double strand breaks and/ or neutralization of pH gradients leading to changes in cell cycle proteins and apoptosis. The review will discuss the recent findings related to the mechanism involved in the anti-cancer activity of this class of molecules.