Periodic Reporting for period 1 - Target5LO (Targeting 5-lipoxygenase in the context of Acute Myeloid Leukemia)
Reporting period: 2018-03-01 to 2020-02-29
Acute Myeloid Leukemia (AML), a cancer of the myeloid line of blood cells, is the most common type of leukemia in adults (~350.000 new cases yearly worldwide), yet continues to have the lowest overall survival rate of all leukemias (26.9%). Current AML management still relies largely on intensive chemotherapy and stem cell transplantation. Although some AML patients respond to these treatments, most patients that go into remission show disease relapse (up to and 70%). In addition, minimal advances have been made for patients unable to tolerate intensive treatment, for example, older patients. The main objective of this research project was to create a new treatment for AML that is (1) more effective and (2) tolerated by all patients. The fellow aimed to use the anticancer natural product beta-lapachone, an under-exploited drug, which has been shown to target the enzyme 5-lipoxygenase in an AML-specific mechanism to treat the cancer. The fellow developed a new targeting strategy for the drug to guarantee specific uptake of beta-lapachone by AML cells and, importantly, to minimize side effects of the drug on healthy cells. To achieve this goal, an antibody-drug conjugate was built to target the drug to cancer cells. The fellow showed that inhibition of 5-lipoxygenase by the drug beta-lapachone delivered as an antibody-drug conjugate leads to highly effective specific cancer cell death while sparing healthy cells, thereby yielding maximal efficacy while minimizing toxicity.
Initially we performed further research into the 5-lipoxygenase target in AML and found further evidence to validate and extend our initial findings for the relevance of this target in specific leukemias cell killing by beta-lapachone.
We then performed work to synthesise our drug-linker modality for attachment of the drug to our targeting antibody. As part of this process, we developed a new prodrug ‘masking’ technology for attachment of beta-lapachone to the linker that enables additional masking of the toxicity of the drug outside the cell. This novel strategy prevents side effects, for example, by off-target reactive-oxygen species (ROS) generation by the drug’s quinone site, while allowing full intracellular release of the drug upon cleavage of a protease cleavable linker. A stable mimic of the masked drug demonstrated a reduction in off-target side effects with in-vitro models (e.g. reduced toxicity, ROS, methaemoglobin generation). Our new mechanism of protection and release has a stability designed-in that perfectly aligned with our strategy of antibody-mediated therapy.We created site-specifically conjugated homogenous antibody-prodrug conjugates (ADPCs) containing our protected payload and have evaluated their toxicity in leukaemia cell models, stability, and drug release kinetics upon linker cleavage. AML cell killing ability is rapid and efficacious upon ADPC treatment, and in line with the drug toxicity and we anticipate good results from future in vivo experiments.
The new linkers developed will be patented and a manuscript is currently under preparation for publication in a peer–review journal in OPEN ACCESS format. The fellow has also disseminated the research results by participating and presenting the work at international conferences.
We then performed work to synthesise our drug-linker modality for attachment of the drug to our targeting antibody. As part of this process, we developed a new prodrug ‘masking’ technology for attachment of beta-lapachone to the linker that enables additional masking of the toxicity of the drug outside the cell. This novel strategy prevents side effects, for example, by off-target reactive-oxygen species (ROS) generation by the drug’s quinone site, while allowing full intracellular release of the drug upon cleavage of a protease cleavable linker. A stable mimic of the masked drug demonstrated a reduction in off-target side effects with in-vitro models (e.g. reduced toxicity, ROS, methaemoglobin generation). Our new mechanism of protection and release has a stability designed-in that perfectly aligned with our strategy of antibody-mediated therapy.We created site-specifically conjugated homogenous antibody-prodrug conjugates (ADPCs) containing our protected payload and have evaluated their toxicity in leukaemia cell models, stability, and drug release kinetics upon linker cleavage. AML cell killing ability is rapid and efficacious upon ADPC treatment, and in line with the drug toxicity and we anticipate good results from future in vivo experiments.
The new linkers developed will be patented and a manuscript is currently under preparation for publication in a peer–review journal in OPEN ACCESS format. The fellow has also disseminated the research results by participating and presenting the work at international conferences.
During these two years, the fellow has progressed this research to near completion. The fellow has continued working as a postdoc in the same group after the end of the fellowship. She is currently preparing sufficient amounts of the new ADPC for safety and efficacy tests in an immunodeficient mouse model of leukaemia. The in vitro experiments performed showed significant efficacy and the benefit of the targeting strategy developed which minimised known side effects observed with this drug as a free agent. The strategy the fellow developed for masking of toxicity of beta-lapachone until release is triggered inside a target cell is also applicable to other drugs with a similar structure and so will have a wider impact in academic and industrial research, not only in the treatment of leukemias, but also in other cancers.
The fellow is keen for the new therapeutic for AML to have an impact in wider society. The fellow and the supervisor are in discussion with Cambridge Enterprise, the technology transfer department at the University of Cambridge with regards to filing a patent. Further development by licensing of the technology or the start of a new company is currently under discussion. The work funded by this fellowship will then be published in full to allow dissemination of knowledge to the wider research community. Hopefully, this research will translate its potential and lead to new medicines that are more effective and have fewer side-effects to patients, thus benefiting the overall wellbeing of the society.
The fellow is keen for the new therapeutic for AML to have an impact in wider society. The fellow and the supervisor are in discussion with Cambridge Enterprise, the technology transfer department at the University of Cambridge with regards to filing a patent. Further development by licensing of the technology or the start of a new company is currently under discussion. The work funded by this fellowship will then be published in full to allow dissemination of knowledge to the wider research community. Hopefully, this research will translate its potential and lead to new medicines that are more effective and have fewer side-effects to patients, thus benefiting the overall wellbeing of the society.