Exploring Melissa Officinalis Properties for Glioblastoma Multiforme Treatment

Despite advances in molecular biology and biology of tumors, in techniques for cancer detection or in the development of target directed compounds, the treatment of cancer is still a challenge. Thus, although some leukemias are now often curable and breast cancer became a chronic illness after treatment, the prognostic for other neoplasias remain poor. These tumors initially respond to chemotherapy, but eventually became resistant to a broad spectrum of structurally and functionally unrelated anticancer agents characterizing the so-called multidrug resistance (MDR) phenotype. Development of MDR is one of the major obstacles to the success of cancer chemotherapy. In clinical settings, patients that exhibit the MDR phenotype usually do not respond to chemotherapy, present tumor recurrence, develop metastasis and evolve to death. Therefore, the search of drugs able to bypass MDR mechanisms and increase the patient’s life expectancy is of great clinical relevance for cancer therapy. In the last years, several extracts and substances isolated from plants had shown to modulate drug resistance in cancer cells. In 2014, a paper published by Queiroz and collaborators [1] showed that Melissa officinalis essential oil (EO) and its major component citral, are cytotoxic for glioblastoma multiforme cells, killing cells by a mechanism dependent of the production of reactive oxygen species (ROS). Data demonstrating that they also inhibit the transporter protein MRP1 suggest that these components would be of interest for GBM treatment. Here, we discuss the main mechanisms of drug resistance, with emphasis in GBM, and we describe the properties of M. officinalis EO, which could be effective against MDR tumors.