Green production of cryptophycins, promising anti-cancer drugs. – CryptoGreen

To this end, we propose to optimize the microbiological production of cryptophycin-1 thanks to a thorough study of the production under fine-tuned culture conditions (pH, light, nutrients, nitrogen source, etc.) using photo-bioreactors. Furthermore, we propose to complete the description of the biosynthesis of cryptophycin-1, for which several steps are still obscure (the actual precursor of the cryptohycin synthase is unknown). We will use diverse approaches such as isotopic incorporation studies, enzymology of the polyketide synthases involved in the biosynthesis, to decipher this interesting pathway. We also propose to get a more complete picture of the secondary metabolome of the Nostoc strain by using a combination of high-resolution LC-MS data and a bioinformatic approach to build a fingerprinting model based on molecular networking. Using these modern techniques we hope to better describe the production of cryptophycin-1 ad its close analogs by the Nostoc strain. In addition it might be possible using these powerful technologies, to identify new analogs of cryptophycin-1 that might be potent new anti-cancer drug leads.
Lastly, we propose to prepare by semisynthesis new cryptophycin conjugates. These new conjugates will be vectorized using for instance neuropilin ligands to lower the toxicity of the parent molecules by specifically targeting the cancer cells. All these new compounds will be tested on a dedicated screening platform to determine their anti-proliferative properties.
The three teams, members of this consortium, have complementary expertise and cover many important fields for the present project: bioprocess applied to the culture of photosynthetic microorganisms, the study of the biosynthesis of cyanobacterial specialized metabolites, expertise in analytical chemistry and in particular in LC-MS derived technologies, metabolomics, medicinal chemistry and natural product chemistry, screening of potential anti-cancer molecules. We believe that we will be able at the end of this three-year program to produce using an environmental-friendly bioprocess new cryptophycin conjugates with promising anti-cancer properties.

To be announced.

The CryptoGreen project outcomes will certainly have short-term impact in the field of bacterial specialized metabolism. We anticipate to shed light on the biosynthesis of cryptophycin-1 and in particular to identify the initial precursor (the starter) of cryptophycin synthase. This result should be easily transposed to the biosynthesis of microcystins. We also anticipate to describe a robust bioprocess to produce this cyanobacterial specialized metabolite in large amount. Again, these data should be largely transposable to the production of other cyanobacterial specialized metabolites with potential therapeutic properties. We also believe that the thorough LC-MS study proposed in this project will be very useful for future work on cryptophycin-1 and analogues and should also be transposable to the study of other cyanobacterial specialized metabolite of interest.
The medicinal chemistry strategies proposed in this project to enhance the specificity of cryptophycin-1 as an anticancer drug lead, should lead to interesting outcomes, although these results should come as medium-term impacts. We should be able to bring the proof of concept for using cryptophycin conjugates as potential anticancer drugs. Furthermore, we should be able to produce new chemical strategies to transform cryptophycin-1 and its analogues that should be very useful to other medicinal chemists.
Finally, a long-term goal of the present proposal is to produce a drug candidate based on all the data produced during this three-year project.
All the data produced all along the three-year project will be published and presented using the usual scientific communication networks. We anticipate to publish in high quality peer-reviewed scientific journals the data produced by the consortium. We also intent to present our achievements at international symposiums.

To be announced.

Cryptophycin-1 is a cyclic depsipetide produced by Nostoc cyanobacteria. This cyanobacterial specialized metabolites is an extremely potent antiproliferative agent. However, its use, or the use of close structural analogues, as a therapeutic agent to treat cancers, has been hampered by its substantial toxicity. Fortunately, very recent works have shown that cryptophycin conjugated to internalizing peptides, were more selective and thus presented a reduced toxicity, and were thus particularly interesting drug leads.
We propose, in this collaborative project involving three academic laboratories with complementary expertise, to microbiologically produce cryptophycin-1 from a cyanobacterial Nostoc strain cultivated in photo-bioreactors, and to prepare by semisynthesis new conjugates that might serve as drug leads for future anti-cancer drugs. The originality of this project lies in the fact that we shall use a photosynthetic microorganism to produce a high-value-added molecule rather than using a classical organic synthesis. Our primary goal is to replace the chemical synthesis by an environmental-friendly bioprocess.
To this end, we propose to optimize the microbiological production of cryptophycin-1 thanks to a thorough study of the production under fine-tuned culture conditions (pH, light, nutrients, nitrogen source, etc.) using photo-bioreactors. Furthermore, we propose to complete the description of the biosynthesis of cryptophycin-1, for which several steps are still obscure (the actual precursor of the cryptohycin synthase is unknown). We will use diverse approaches such as isotopic incorporation studies, enzymology of the polyketide synthases involved in the biosynthesis, to decipher this interesting pathway. We also propose to get a more complete picture of the secondary metabolome of the Nostoc strain by using a combination of high-resolution LC-MS data and a bioinformatic approach to build a fingerprinting model based on molecular networking. Using these modern techniques we hope to better describe the production of cryptophycin-1 ad its close analogs by the Nostoc strain. In addition it might be possible using these powerful technologies, to identify new analogs of cryptophycin-1 that might be potent new anti-cancer drug leads.
Lastly, we propose to prepare by semisynthesis new cryptophycin conjugates. These new conjugates will be vectorized using for instance neuropilin ligands to lower the toxicity of the parent molecules by specifically targeting the cancer cells. All these new compounds will be tested on a dedicated screening platform to determine their anti-proliferative properties.
The three teams, members of this consortium, have complementary expertise and cover many important fields for the present project: bioprocess applied to the culture of photosynthetic microorganisms, the study of the biosynthesis of cyanobacterial specialized metabolites, expertise in analytical chemistry and in particular in LC-MS derived technologies, metabolomics, medicinal chemistry and natural product chemistry, screening of potential anti-cancer molecules. We believe that we will be able at the end of this three-year program to produce using an environmental-friendly bioprocess new cryptophycin conjugates with promising anti-cancer properties.