Fresh from acquiring TEF Labs’ Fluo 3 and Fluo 4 product lines, as well as biotech firm Sentigen and its Tango GPCR screening assay, Invitrogen intends to continue its strong focus on cellular analysis technologies, a company official said this week.
Invitrogen also said it intends to seek alliances with instrument manufacturers to boost sales of TEF’s calcium indicators.
“There is a greater focus on cell-based assays — that is simply because those cell-based assays move us closer to putting biology into context, rather than looking at molecules in isolation,” Vicki Singer, director of the labeling and detection technologies business segment for Invitrogen, told CBA News sister publication BioCommerce Week this week.
“As we build the toolbox, we’re going to be moving more and more to understand the cell, the cell in its milieu, and how it interacts — and that is a very deliberate, broad strategy,” she added.
Invitrogen last week said it has regained the sole rights to TEF’s calcium indicators. The dyes had been manufactured and sold by both TEF and Invitrogen division Molecular Probes for several years after Molecular Probes licensed them to TEF as part of a legal settlement between the companies prior to Invitrogen’s acquisition of Molecular Probes in August 2003.
As part of the Fluo 3 and Fluo 4 deal, Invitrogen also acquired products that TEF Labs developed independently, Singer said. “They are all fluorescent calcium indicators, and some of them have other properties that might be useful to a particular market niche,” she said.
“Invitrogen, that is Molecular Probes, invented Fluo 4 a number of years ago,” Singer added. “TEF Labs started manufacturing and selling it, [and] there was a legal dispute between the parties that resulted in a settlement agreement whereby TEF Labs was the only other party that was able to manufacture this material.”
She said that it was a goal of Invitrogen to get these particular calcium indicators back in house. The probes “represent one of the core technologies developed by Invitrogen [via Molecular Probes] and one of the core areas of expertise for the company,” said Singer.
There are other calcium indicators on the market, but “most other parties that sell calcium indicators are, in fact, selling some of the weaker ones,” Singer said. “There are a number of licensees of the University of California’s Fluo 3 patent, and they’re all selling that product. There is no other party that has a molecule comparable to Fluo 4.”
The Fluo 4 technology is particularly important to Invitrogen, Singer said, because it offers some distinct advantages over other indicators. “Fluo 4 is a perfect spectral match to the argon ion laser that’s used in high-throughput instrumentation for screening for drug candidates,” she said. Fluo 3 is not as good of a match, since it is less bright, Singer noted.
“The invention of Fluo 4 is part of a broader invention on the part of Molecular Probes of fluorinated fluorescein,” said Singer. “These are molecules that contain fluorine attached to them, and that fluorine provides them with higher brightness. In addition, it makes them more photostable, so they bleach less in the presence of light, and it makes them less pH-sensitive.”
Singer also said that Invitrogen “is starting to, and will be doing more, work with a number of instrument manufacturers in this area.”
The GPCR Stable
The acquisition of the Fluo 3 and Fluo 4 product lines came one week after Invitrogen said it would acquire cell-based assay company Sentigen Holding, along with its Tango GPCR and protein-protein interaction screening technology and division-arrested cell lines, for around $25.9 million in cash (see CBA News, 9/8/2006).
“As we build the toolbox, we’re going to be moving more and more to understand the cell, the cell in its milieu, and how it interacts — and that is a very deliberate, broad strategy.”
The Sentigen acquisition and the Fluo 3 and 4 deals are aimed primary at bolstering Invitrogen’s GPCR screening play, and overlap each other quite a bit, according to Singer.
“A drug-discovery partner might be interested first in a primary screen and looking at a calcium response, and that’s what the Fluo 3 and Fluo 4 [dyes] are used for,” said Singer. “It’s the most pervasive assay in all of biology, because calcium changes are indicative of many, many different cellular events. The protein-protein interaction assays that Sentigen brings us will be used for a subset of drug candidates, but many of those may have been screened first for calcium.”
In addition, both technologies overlap with Invitrogen’s popular GeneBLAzer β-lactamase-based transcriptional reporter assay. Last week, Invitrogen officials told CBA News that GeneBLAzer, which can be used for GPCR screening but may not be ideal for it, would produce better readouts when combined with the newly acquired Tango assay.
In addition, according to a recently published research article by Bonnie Hanson, a scientist in Invitrogen’s Madison, Wisc.-based Discovery Sciences unit, Fluo 4-based assays and GeneBLAzer can be multiplexed to improve high-throughput GPCR screening.
According to the abstract of the article, published in the September issue of the Journal of Biomolecular Screening, multiplexed Fluo 4 and GeneBLAzer screening of GPCR targets in Jurkat and CHO cell lines produced 100-percent correlation of on-target hits and identified several false positives associated with the individual assay formats.
“In addition to enhanced reliability, this method saves time and money because only half the amount of compounds, cells, and consumables [is] needed to screen a cell line in a multiplexed mode versus separate screening by both methods,” Hanson wrote in the abstract.