BioWorld International Correspondent

BORNHEIM, Germany - Cellzome GmbH completed a EUR34 million (US$31.7 million) second round of financing to fund its work in proteomics.

Cellzome was formed in partnership with the European Molecular Biology Laboratory (EMBL) in May 2000 to identify drug targets by proteomics and to exploit them for discovery of small-molecule lead compounds, the company's CEO, Charles Cohen, told BioWorld International.

The money raised will allow Cellzome, of Heidelberg, Germany, to expand the scope of its research and development program and to increase the throughput of its technology platform.

To identify drug targets, the company investigates whole protein complexes.

"It's the protein complex that is responsible for biology rather than single proteins alone," Cohen said. "Concerning the genes BRCA1 and BRCA 2 [which may be important for understanding the onset and progression of breast cancer], the pharmaceutical industry has historically focused on using these gene products as drug targets. However, there are 10 or 11 other proteins involved in the assembly of the BRCA complex that control an aspect of DNA repair that may be better suited to drug discovery."

Cellzome recovers protein complexes inside the cell by attaching tags to bait proteins of interest. "We then purify these complexes using a two-step affinity chromatography procedure," Cohen said. The purified complexes are then characterized using mass spectroscopy.

"Once we have a partial amino-acid sequence of a complex's proteins, we gather all available information on them in databases and the scientific literature," Cohen said. By tagging particular proteins one can identify the other proteins in the cell that are involved in the same biological process. Cohen compared it to an orchestra: " If you hear a violin playing in an orchestra, you know where to look for the other strings."

Cellzome also does functional analyses on the protein complexes. "We determine whether or not the complexes are differentially assembled in healthy vs. sick cells, and how drugs influence the complexes' composition," he said.

Cellzome already has identified several protein complexes.

"We'll take our targets and screen libraries of small-molecule compounds to identify potential drug leads," Cohen said. "If you'll have a look at us in six to 12 months you will see that we are a drug development company," he said, adding that recruitment of specialists in drug development is just starting. "At the moment our staff is 45 employees; all but four are scientists. By the end of the year our staff will be 80 or 90 people."

Cellzome had raised EUR42 million since its inception.

Investors in the current round of financing include Index Ventures, of Geneva, Switzerland; Sofinnova Ventures, of Paris; and Schroders Investment Management Ltd., of London. Existing investors who also supported the financing round include Atlas Venture, Advent International, Heidelberg Innovation and the company's founders.

Founders are Spyros Artavanis-Tsakonas, director of developmental biology and cancer at the MGH Cancer Center and the Harvard Medical School; Peer Bork, senior scientist at the EMBL (Bioinformatics) in Heidelberg and at the Berlin-based Max Delbrück Center for Molecular Medicine; Rüdiger Klein, Angel Nebreda, Gitte Neubauer, Bertrand Seraphin, Matthias Wilm and Giulio Superti-Furga, all from EMBL; Stelios Papadopoulos, managing director in the investment banking division at SG Cowen and co-founder of Exelixis Inc.; and Cohen. Cohen was among the founders of Creative BioMolecules Inc., a co-founder and board member of Exelixis, and co-founder and director of Xenon Genetics Inc., a population-based genomics company.