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ANR funded project

Emergence de produits, technologies, ou services à fort potentiel de valorisation (Emergence)
Edition 2011


IGF-TRAP


Development of mini-IGFBP-3 (EP 11 305 197.3 24): Preclinical Proof of concept of its in vivo anti tumor activity

Development of a new anti-IGF agent in Cancer therapy
IGF signalling pathway activation contributes to the initiation and progression of human malignancies but also to their résistance to current therapies. Therapeutic targetting of this pathway thus looks as a promissing approach which could lead to substantial therapeutic advances.

IGF-Trap : Ligand neutralization as an alternative strategy to target IGF signalling pathway in oncology.
After becoming an attractive therapeutic target in Oncology, IGF axis generated the emergence of new therapeutic agents (monoclonal antibodies or tyrosine kinase inhibitors) targeting IGF-1R some of them being currently evaluated in clinical trials. We explore an alternative approach aimed at neutralizing IGF-I and IGF-II taking advantage of a human protein present in serum, the sequence of which was modified so as to resist proteolytic cleavage while retaining its intrinsic binding properties. Thus, ligand neutralization disactivates IGF signalling pathway reducing both cell proliferation and resistance to apoptosis. Furthermore, administration of this protein restores an homeostatic balance broken by the tumor to its advantage. This is achieved through proteolytic cleavage of endogeneous IGFBP-3 which leads to massive release of free IGFs. Thus, IGF-Trap administration should break this vicious circle profiting tumor expansion and thereby lead to improve current therapies.

Ligand approach to IGF-axis targetting : Production of mini-IGFBP-3.
To achieve our goal of ligand neutralization we chose to modify human IGFBP-3, the mais “carrier” of IGFs in the blood stream. This choice has three advantages: i) it is a human protein present in the bloodstream, ii) its affinity is high for both IGF-I and IGF-II, iii) its use in humans has already been approved by FDA in some indications. To abolish its sensitivity to proteolytic enzymes, we replaced part of its sequence by site-directed mutagenesis and replaced it by a flexible linker. This step led to mini-IGFBP-3 and the recombinant protein was produced as a secretory protein using the baculovirus-insect cell system. A patent application was then filed with Inserm-Transfert. Other recombinant versions of this protein have been produced including an immunoadhesin and a fusion protein enabling its enzymatic biotinylation which could facilitate its tissue targeting.

Results

To achieve our goal of ligand neutralization we chose to modify human IGFBP-3, the mais “carrier” of IGFs in the blood stream. This choice has three advantages: i) it is a human protein present in the bloodstream, ii) its affinity is high for both IGF-I and IGF-II, iii) its use in humans has already been approved by FDA in some indications. To abolish its sensitivity to proteolytic enzymes, we replaced part of its sequence by site-directed mutagenesis and replaced it by a flexible linker. This step led to mini-IGFBP-3 and the recombinant protein was produced as a secretory protein using the baculovirus-insect cell system. A patent application was then filed with Inserm-Transfert. Other recombinant versions of this protein have been produced including an immunoadhesin and a fusion protein enabling its enzymatic biotinylation which could facilitate its tissue targeting.

Outlook

After the proof of concept of IGF-Trap efficiency on tumor growth is validated, it will become timely to start a company in charge of licensing this technology to a pharmaceutical company. In the long run, this biomolecule could be used as a new in Oncology either as a single agent in sensitive pathologies such as Ewing Sarcoma or adrenocortical carcinoma, or as an adjuvant in less responsive pathologies (colo-rectal cancer in association with cetuximab)

Scientific outputs and patents

PCT/EP2012/053142

Partners

INSERM U749  INSTITUT NATIONAL DE LA SANTE ET DE LA RECHERCHE MEDICALE - DELEGATION REGIONALE PARIS XI

INSERM UMR_S 938 CDR St-Antoine INSTITUT NATIONAL DE LA SANTE ET DE LA RECHERCHE MEDICALE - DELEGATION REGIONALE PARIS VI

Inserm-Transfert INSERM-TRANSFERT

Institut Curie INSTITUT CURIE - SECTION DE RECHERCHE

ANR grant: 313 046 euros
Beginning and duration: février 2012 - 24 mois

Submission abstract

There is considerable current interest in targeting the IGF axis as a therapeutic strategy in oncology, with more than a dozen drug candidates undergoing clinical evaluation. Receptor-oriented strategies, targeting IGF receptor (IGF-1R) (either mabs of TKI) have been developed first. Even though clinically significant activity has been reported, some Ph3 clinical trials were disappointing and have been discontinued.
Less attention has been paid to neutralizing the ligands themselves even though promising effects have been reported in pre-clinical studies using ligand-specific antibodies. IGF biding proteins are high affinity endogeneous actors of the IGF axis playing a major role in regulating IGF bioavailability. IGFBP-3 transports > 75% of serum IGF-I and –II and its activity is controlled by various proteases including MMPs active in metastatic cancer cells. Thus, IGFBPs could be used as an alternative to antibodies in targeting the IGF axis.
We have produced a set of protease-resistant muteins of human IGFBP-3 (IGF-TRAP) for which a European patent application (EP 11 305 197.3) has been filed by Inserm-Transfert. In line with its in vitro anti-proliferative properties, preliminary data have been obtained indicating in vivo activity. Thus, this modified IGF binding protein could offer, a valuable alternative to receptor-oriented agents. Advantages of IGF-TRAP are i) neutralizes simultaneously IGF-I and IGF-II ii) targets both IGF-1R and IR-A signal transduction pathways iii) restores in the patient a balance destroyed by the tumor. The IGF-TRAP project seeks to further assess its properties and aims at delivering a definite proof of concept of its anti-tumor activity in vivo which will pave the way for a future biotechnology company.
Our program will compare sets of tumor xenografts in mice treated or not by IGF-TRAP. We will focus on two types of “IGF-sensitive” tumor cell lines: i) IGF-II producing tumor cell lines; ii) Ewing’s sarcoma cell lines selected due to their responsiveness to anti-IGF1R therapy demonstrated in clinical trials. To generate meaningful in vivo data we need to produce adequate quantities of protein a task attributed to subcontractant 1. Read out criteria will concern signaling, cell cycle, angiogenesis and apoptosis proteins. They will encompass immunoblots (partner 1 and partner 2) evaluation of the antitumor activity on xenografts (partner 2) and immunohistochemistry (subcontractant 2). Specific in vitro experiments will concern Ewing’s sarcoma cell lines (partner 3) and other cell lines (co-coordinator). In addition, specific cell lines will be used to collect data by FDG-TEP (partner 1and in vivo fluorescence imaging (partner 2). It is our hope that this in vivo proof of concept will serve as a basis for the development of our patented set of therapeutic proteins.

 

ANR Programme: Emergence de produits, technologies, ou services à fort potentiel de valorisation (Emergence) 2011

Project ID: ANR-11-EMMA-0051

Project coordinator:
Monsieur François GODEAU (INSTITUT NATIONAL DE LA SANTE ET DE LA RECHERCHE MEDICALE - DELEGATION REGIONALE PARIS VI)
francois.godeau@nullinserm.fr

 

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The project coordinator is the author of this abstract and is therefore responsible for the content of the summary. The ANR disclaims all responsibility in connection with its content.