MitoSciences said last week it will use its cell-based MitoTox technology in a collaboration with Roche to generate mitochondrial toxicity profiles for more than 100 known kinase inhibitors.
Under the terms of the agreement, Roche will provide the compound library and previously gathered in vitro and in vivo data, and MitoSciences will use MitoTox to provide a more detailed set of mechanistic in vitro data for a broad range of mitochondrial toxicity endpoints.
Although Roche’s data includes some general mitochondrial toxicity endpoints, such as membrane potential and oxygen consumption, this project will take a systematic approach to generating a full set of data describing all of the potential mechanisms of mitochondrial inhibition for a large set of kinase inhibitors, a MitoSciences official told CBA News.
Kinase inhibitors are an increasingly popular drug type so the need to understand their effect on mitochondria is particularly significant, said MitoSciences CEO Jean-Paul (John) Audette. Symptoms of mitochondrial toxicity, which can be fatal, include myopathy, peripheral neuropathies, and lactic acidosis.
“There is a growing recognition among pharmaceutical companies that understanding mechanisms of mitochondrial inhibition is very important, and it is important to try to identify those mechanisms as early in the drug development process as possible,” Audette said.
MitoTox is a set of cell-based assays that MitoSciences provides as a service that enables researchers to measure how a compound affects all of the different known mechanisms of mitochondrial inhibition. These include direct inhibition of oxidative phosphorylation, inhibition of mitochondrial biogenesis, reduction of overall mitochondrial protein expression, oxidative stress, and the induction of apoptosis.
“MitoTox allows you to get quantitative data on each of these different endpoints so that you can get a very precise profile of a drug’s mitochondrial toxicity,” Audette said.
“There is a growing recognition among pharmaceutical companies that understanding mechanisms of mitochondrial inhibition is very important, and it is important to try to identify those mechanisms as early in the drug development process as possible.”
These assays are already part of the MitoTox service, so this project is meant to be completed within a few months, according to Kyle Kolaja, director of discovery and investigative safety at Roche Palo Alto, which is leading the project.
“From our end, we will then be integrating a lot of the results from the collaboration into the existing data that we have generated [at Roche] on other endpoints related to cell viability, proliferation, permeability, cytoskeletal function, apoptosis, lipid metabolism, et cetera,” he said.
Roche will then look at what molecules are causing mitochondrial toxicity and try to understand their kinase inhibition profile so that “we can understand how particular kinase inhibitors and which particular kinases are critical to mitochondrial toxicity in the heart,” said Kolaja.
The project is an extension of studies Roche has been performing in recent years in order to understand kinases and the potential toxicities of kinase inhibitors. The Swiss drug maker currently markets the kinase inhibitor erlontinib (brand name Tarceva) for the treatment of non-small cell lung cancer and (in combination with gemcitabine) pancreatic cancer.
The MitoSciences project will include more than 100 compounds that Roche has profiled in a primary cardiomyocyte model. “As we looked at these results, it is pretty clear that many of these compounds that are kinase inhibitors are also causing toxicity to the mitochondria,” Kolaja told CBA News this week.
Roche has an existing relationship with MitoSciences. According to Kolaja, Roderick Capaldi, co-founder and CSO of MitoSciences, “knows how to assay mitochondrial function and mitochondrial effects, so we are leveraging his abilities and MitoSciences’ abilities to understand what a particular molecule is doing to the mitochondria.”
To understand mitochondrial toxicity, the scientists will study how a compound affects oxidative phosphorylation and observe the proteins that are expressed in the mitochondria, including those responsible for cellular energy and fatty acid metabolism.
“We have been adding things here and there that are related to the Krebs cycle, and other aspects of energy creation, as a means to understanding not just what particular endpoints within the mitochondria are affected by these compounds, but also what kinases are regulating these processes,” Kolaja explained. This work will give scientists at Roche a better understanding of how toxicity from kinase inhibitors occurs within the mitochondria, he added.
Ace of Kinases
Eugene, Ore.-based MitoSciences was founded in 2003 by two University of Oregon researchers: Capaldi and Michael Marusich, vice president of research and development.
“We focus on developing antibodies, monoclonal antibodies exclusively, with a particular emphasis on antibody pairs that can be used for doing quantitative expression analysis in sandwich-type ELISAs,” said Audette. The antibodies were developed for use in assays that were developed in-house.
MitoSciences also works with other partners to develop different types of multiplexing assays for pharmaceutical companies and molecular diagnostics applications.
The majority of MitoSciences’ customers are working in basic research and using its kits and antibodies to identify the role of mitochondria in various disease states, and to understand the structure and function of the mitochondria and the biochemistry of the organelle, Audette said.
“Increasingly, our emphasis is less on mitochondria and more on understanding different key pathways in intermediary metabolism,” said Audette. He said that MitoSciences is also looking at enzymes outside of the mitochondria that are involved in these pathways.
“Our goal as a company is to have antibodies against all of the key enzymes involved in intermediary metabolism. That would cover oxidative phosphorylation, the Krebs cycle, glycolysis, glucogenesis, et cetera,” said Audette.
He said that cell-based assays will play a significant role in the expanded focus of the company. “It is a very important part of our work that the antibodies be reactive with, and that the assays work, using cultured cells,” Audette explained.
The company is currently housed in an approximately 8,000 sq. ft. facility in the Riverfront Research Park at the University of Oregon. However, that soon may be too small a space. As the company expands its focus to look past mitochondria to intermediary metabolism, it is planning to hire more people, according to Audette. The company currently employs 27 people, and has doubled in size over the last year, he said.
“We are planning to hire for R&D and our production team to increase our manufacturing and QC capacity. We are also hiring in marketing and sales,” Audette said. The company is looking at probably hiring between five and 10 people by the end of the year.
Audette said that the majority of MitoSciences’ clients are pharmaceutical companies, though its “eventual goal” is to create kits for drug makers to perform the research in-house.
Kinases have a very important role to play in modulating certain metabolic pathways and other cell processes, because they phosphorylate other proteins, which in turn activates or deactivates those proteins.
A number of different factors can influence whether kinases are themselves upregulated or downregulated, or whether they are active or inactive. Drug companies are placing a strong emphasis on developing drugs against specific kinases, in the hope that by inhibiting a kinase, it can have some beneficial effect in the cell.
The diseases that kinase inhibitors are used to treat include cancer, diabetes, and inflammation. Few kinase inhibitors have made it to market, however, despite a growing recognition of their potential importance as a drug class.
One reason is their potential for adverse effects, which include general and mitochondrial toxicities. They can also have off-target effects. “Often, if you develop a drug that can inhibit one kinase, it will very likely inhibit another kinase as well. That off-target inhibition may have detrimental effects on an organism and cell health,” Audette said.
Many of the kinase inhibitors on the market actually inhibit multiple kinases. In certain cases, that is by design, or the off-target effects have been found not to be deleterious, so they are just accepted.