Sensitizing multidrug-resistant leukemia cells to common cytostatics by an aluminium-salen complex that has high-apoptotic effects in leukemia, lymphoma and mamma carcinoma cells

We investigated the aluminium-salen complex MBR-8 as a potential anti-cancer agent. To see apoptotic effects induced by MBR-8, alone and in combination with common cytostatic drugs, DNA-fragmentations were studied using the flow cytometric analysis. Western blot analysis and measurement of the mitochondrial membrane potential with a JC-1 dye were employed to identify the pathway of apoptosis. An impressive overcoming of multidrug-resistance in leukemia (Nalm6) cells was observed. Additionally, solid tumor cells including Burkitt-like lymphoma (BJAB) and mamma carcinoma cells (MCF-7) are affected by MBR-8 in the same way. Western blot analysis revealed activation of caspase-3. MBR-8 showed very pronounced selectivity with regard to tumor cells and high synergistic effects in Nalm6 and daunorubicin-resistant Nalm6 cells when administered in combination with vincristine, daunorubicin and doxorubicin. The aluminium-salen complex MBR-8 showed very promising anti-cancer properties which warrant further development towards a cytostatic agent for future chemotherapy. Studies on aluminium compounds for cancer therapy are rare, and our report adds to this important body of knowledge.

Discovery of a cobalt (III) salen complex that induces apoptosis in Burkitt like lymphoma and leukemia cells, overcoming multidrug resistance in vitro

A very small number of cobalt complexes is examined in oncology research. In this work, we investigate the cobalt (III) salen complex MBR-60 that turns out to be a promising anticancer drug. It induces apoptosis in Nalm6 leukemia and BJAB lymphoma cells and overcomes multidrug resistances by blocking the drug efflux pump P-glycoprotein. It further develops the apoptotic effects over the intrinsic pathway. An activation of caspase-3, caspase-8 and caspase-9 can be detected by western blot analysis. The independence of CD95 is shown by similar apoptotic inductions in BJAB and BJAB FADDdn cells. MBR-60 displays synergistic effects with daunorubicin and vincristine and has a selectivity to tumor cells. In comparison to the apoptotic effects of MBR-60 in BJAB lymphoma cells, the cobalt-free ligand 5 does not influence these cells. The research highlights that a cobalt complex has a therapeutic potential for cancer treating with a focus on drug-resistant tumors.