AxCell Biosciences set to use Molecular Staging's rolling circle amplification technology
Protein interactions meet biochips in this conjoining of two technologies
Table of Contents
What is RCAT?
Ultra-sensitive PSA assay demonstrates promise
Company profiles
AxCell Biosciences Corp., a subsidiary of Cytogen Corp. (Princeton, NJ), and Molecular Staging Inc. (MSI; Guilford, CT) are investigating potential synergies between their technologies to map protein pathways rapidly and efficiently. MSI's Rolling Circle Amplification Technology (RCAT) is a proprietary, highly sensitive and efficient amplification method for detecting the presence of target molecules micro-arrayed on a biochip. By combining AxCell's domain-ligand interaction technology with MSI's protein arrays, the companies believe that they may be able to increase the rate of protein interaction measurements by 10 fold more than AxCell's current rate of approximately 10,000 interactions per day.
"By amplifying the signals used to detect protein interactions, we plan to measure many different targets simultaneously on a biochip," explained John D. Rodwell, AxCell's acting president and chief technical officer. "Although our current proprietary process for measuring protein-to-protein interactions continues to function successfully at planned commercial scale, this combined technique could allow us to use less material and to operate more efficiently using readily available equipment. Potential benefits of combining these automatable technologies include, ultra-high throughput affinity mapping and application of chip-based target arrays to protein expression."
What is RCAT?
RCAT is a sensitive and efficient amplification method that can be used to detect target molecules in a wide array of testing formats. It is the only amplification method that can recognize, amplify, and detect targets directly on a solid surface, such as within a cell (in situ analysis) or on a microarray/biochip. It solves several problems inherent in the Polymerase Chain Reaction (PCR), the technology most commonly used to detect genes and their mutations.
Currently, gene arrays place spots or "elements" in a high-density matrix on slides. Each spot contributes a single piece of genetic information to the analysis. From a single element in such an array, RCAT can obtain information on multiple analytes simultaneously, exponentially increasing the level of information available. Since RCAT can amplify and detect signal from a solid-phase target simultaneously, it provides the only means for a homogeneous biochip assay.
Driven by DNA polymerase, RCAT can replicate circular oligonucleotide probes with either linear or geometric kinetics under isothermal conditions. In the presence of two suitably designed primers, a geometric amplification occurs via DNA strand displacement and hyperbranching to generate 1012 or more copies of each circle in one hour. In addition to grossly amplifying a signal, this method—called Exponential-RCAT (E-RCAT)—is adequately sensitive to detect point mutations in genomic DNA.
Ultra-sensitive PSA assay demonstrates promise
As part of a separate ongoing collaboration between Cytogen and MSI, the companies report that they have achieved their first milestone - proof of principle for an ultra-sensitive serum assay for prostate specific antigen (PSA), a widely used marker for the screening and detection of prostate cancer. Results using a panel of five antibodies to PSA indicate that the new RCAT-based assay has a sensitivity of more than 100 fold greater than existing commercial blood tests.
Cytogen believes that an ultra- sensitive assay might lead to earlier detection of recurrent prostate cancer. The next step is the selection of one antibody for commercial development. The companies are also in the process of applying RCAT technology to establish proof of principle for an ultra-sensitive assay for prostate specific membrane antigen (PSMA), which Cytogen believes may have greater prognostic value than the PSA test alone.
Company profiles
AxCell Biosciences Corp. has begun a two-to-four year project to develop a comprehensive, proprietary database of human protein signaling pathways as a tool for identifying new drug targets. Protein-protein interactions form the core of the company's Inter-functional Proteomic Database (IFP). AxCell is offering the IFP Database to the pharmaceutical industry as a tool to accelerate the drug discovery process. AxCell Biosciences has agreed to enter into a collaboration with the Institute for Systems Biology to elucidate aberrations in protein signaling pathways underlying the metastatic spread of prostate cancer.
Molecular Staging Inc. is a privately held biotechnology company developing improved diagnostic tests for a variety of diseases and advanced tools for genetic analysis. MSI's core technology, Rolling Circle Amplification Technology, is a highly sensitive and efficient nucleic acid amplification technique that can be used to better detect, diagnose, and stage disease. Its technologies enable the rapid identification of molecular abnormalities affecting genes, proteins, and small molecules.
For more information: Axcell Biosciences Corp., 826 Newtown-Yardley Rd., Suite 100, Newtown, PA 18940-1720. Tel: 267-757-1200. Fax: 267-757-1301.
Edited by Laura DeFrancesco
Managing Editor, Bioresearch Online
ldefrancesco@bioresearchonline.com
Source: Cytogen Corp.