Studies on the optimization of leukemia and non-Hodgkin lymphoma therapies using opioids, chemotherapy and radioimmunotherapy

Despite complex treatment schedules for cancer, the occurrence of resistances and relapses is a major concern in oncology. Hence, novel treatment options are needed. In this thesis, different approaches using radioimmunotherapy and the opioid D,L-methadone alone or in combination with doxorubicin were analyzed regarding their cytotoxic potential and the triggered signalling pathways in sensitive and resistant leukaemia and non-Hodgkin lymphoma (NHL). The radioimmunoconjugates [Bi-213]anti-CD33 and [Bi-213]anti-CD20 for treatment of acute myeloid leukaemia (AML) or NHL, respectively, were applied exemplary for the use of targeted alpha-therapies (TAT). Depending on the analyzed cell lines, the used activity concentrations and specific activities (MBq/μg antibody) apoptosis was induced abrogating radio- and chemo-cross-resistances specifically. The cell death was caspase-dependent activating the mitochondrial pathway and was executed by downregulation of the anti-apoptotic proteins XIAP and Bcl-xL. D,L-Methadone induces apoptosis in vitro and in vivo in opioid-receptor (OR) expressing cells depending on the OR density and the used concentrations. Resistances could be overcome and proliferation was inhibited. In combination with doxorubicin, a synergistic effect regarding cytotoxicity in ex vivo patient cells and cell lines was observed. This effect depends on the increase of doxorubicin uptake co-administering D,L-methadone whereas doxorubicin enhances OR expression. The activation of OR leads to the downregulation of cAMP playing a pivotal role in apoptosis induction. In vivo, the therapeutic potential of D,L-methadone alone or in combination with doxorubicin could be proven as mice transplanted with human T-ALL-cells could be identified as tumour free. In summary, these studies show that TAT using [Bi-213]anti-CD33 and [Bi-213]anti-CD20 as well as the opioid D,L-methadone harbour the potential to optimize conventional treatment modalities for leukaemia and NHL.