The search of DNA-intercalators as antitumoral drugs: what it worked and what did not work.

The discovery of new compounds with antitumoral activity has become one of the most important goals in medicinal chemistry. One interesting group of chemotherapeutic agents used in cancer therapy comprises molecules that interact with DNA. Research in this area has revealed a range of DNA recognizing molecules that act as antitumoral agents, including groove binders, alkylating and intercalator compounds. DNA intercalators (molecules that intercalate between DNA base pairs) have attracted particular attention due to their antitumoral activity. For example, a number of acridine and anthracycline derivatives are excellent DNA intercalators that are now on the market as chemotherapeutic agents. Commercially available acridine and anthracycline derivatives have been widely studied from a variety of viewpoints, such as physicochemical properties, structural requirements, synthesis and biological activity. However, the clinical application of these and other compounds of the same class has encountered problems such as multidrug resistance (MRD), and secondary and/or collateral effects. These shortcomings have motivated the search for new compounds to be used either in place of, or in conjunction with, the existing compounds. Unfortunately, the results of this search have not met expectations. The vast majority of candidate intercalator compounds tested for use as anticancer agents have shown little or no biological activity. Research in this area has not been without benefits, however, for it has produced much information on the synthesis and antitumoral properties of hundreds of compounds, which have been tested on diverse tumoral cell lines. This review considers the structural and biological considerations relevant to the use of DNA intercalators and bis-intercalators as antitumoral agents, with an emphasis on the relationship between structure and activity, produced in last decade.