SAN DIEGO, March 17, 2005— Genpathway, Inc. announced today that recently completed studies demonstrated the ability of TranscriptionPath™, a component of Genpathway’s integrated suite of novel gene transcription analysis tools, to detect gene expression changes associated with toxic drug effects. Genpathway’s tools measure the process of transcription directly, rather than accumulated RNA levels.

Genpathway presented these and other results involving specific applications of TranscriptionPath™ to toxicology and pharmaco/toxicogenomics at the 2005 Society of Toxicology Annual Meeting held in New Orleans.

Pharmacogenomic and toxicogenomic studies often require analysis of gene expression changes in tissues that were not frozen immediately, such as tissue from human cadavers or deceased animals held for hours under suboptimal conditions. Due to the inherent instability of RNA, evaluation of these tissues using RNA profiling, including conventional microarray analysis, has proved challenging.

“These studies demonstrate the significant value of Genpathway’s suite of tools in enabling toxicologists to analyze tissues from animals and humans in basic toxicology and pharmaco/toxicogenomic applications with high reproducibility and sensitivity, including cases in which RNA is likely to be degraded,” said Mary Warren, Chief Scientific Officer of Genpathway.

Genpathway’s scientific presentation highlighted the results of studies involving analysis of postmortem tissues that had been stored under suboptimal conditions for up to 24 hours. Mice were initially dosed with compounds known to induce liver toxicity for varying amounts of time. Livers were assayed by TranscriptionPath™ and also for RNA levels using reverse-transcriptase PCR. Key findings included:

• Levels of transcription measured in livers contained within animals stored for 24 hours (3 hours at room temperature plus 21 hours at 4 degrees C) prior to removal and analysis were similar to those found in tissue that was processed immediately. In contrast, RNA levels from the stored animal tissues were very low due to degradation.
• Mice dosed with the same compounds for up to 48 hours followed by processing of the livers under optimal conditions showed that TranscriptionPath™ detected gene expression changes with greater accuracy compared with measurement of RNA levels. The improvement was particularly striking with regard to the timing of the gene expression changes and the extent of those changes.

The results of these studies confirmed previously obtained results by the company showing that RNA degrades but transcription complexes are stable. The findings also demonstrated that, even for optimally processed tissues, TranscriptionPath™ determined gene expression changes associated with toxicology more accurately than RNA profiling—particularly with regard to timing of gene activation and repression, and the levels of those changes.

Genpathway’s innovative tools—TranscriptionPath™, FactorPath™ and PromoterPath™— can be used on any type of fresh or frozen cells or tissues from any species. The results of these studies may be found at www.genpathway.com.

ABOUT GENPATHWAY, INC.
Genpathway is a systems biology company developing innovative tools that identify and analyze complex biological pathways to drive discovery and testing of novel pharmaceuticals, biomarkers and diagnostic tests.