Invitrogen will continue to increase its presence in the high-content screening market over the coming months with a series of new product releases, the validation of reagents for high-content cell-based assays, and possible partnerships with existing HCS vendors, company officials told CBA News this week.
The growth plan is part of the company’s belief that the HCS market has not yet lived up to its promise of developing adequate validated assays because vendors have been paying too much attention to individual technologies rather than enabling specific applications, the Invitrogen officials said.
“What we’ve heard from customers is the need for validated assays, and that’s the direction we’re heading,” said Jeff Hung, high-content screening product manager at Invitrogen.
To that end, Invitrogen plans to release an HCS-validated version of its recently launched LipidTOX assay for assessing cytotoxicity based on cellular lipid metabolism; fluorescent dyes with extremely sharp emission spectra to allow more accurate image segmentation and better multiplexing; HCS-certified antibody labels, and a version of its GeneBLAzer β-lactamase assay for high-content applications.
The company also plans to coordinate many of these activities with IBC’s Drug Discovery Technology conference being held next week in Boston, as well as September’s Society for Biomolecular Sciences annual meeting in Seattle, officials said.
Invitrogen, through both legacy products and acquisitions such as Molecular Probes, has always offered a plethora of reagents including antibodies, fluorescent dyes, and semiconductor quantum dots that are frequently used by HCS users both in pharma and academia.
The use of these products, however, has traditionally been in a “homebrew” fashion, however – customers simply purchase the appropriate reagents from Invitrogen and apply them to their HCS research.
“We currently develop our reagents to work with existing HCS algorithms, and in some ways, that’s sub-optimal,” Brett Williams, Invitrogen’s director of imaging and microscopy told CBA News. “Typically when the researchers are developing their own assays, they try and work through multiple algorithms and say, ‘Can I replicate what I’m seeing by eye?’ We’re planning on bringing out reagents that come with software that work on specific platforms. That’s the ultimate intent of where Invitrogen will go.”
To help with this initiative, the company has been working with undisclosed HCS instrumentation houses to develop “complete solutions, so that we have validated reagents for their instrumentation that go with an existing algorithm, or news algorithm that are optimized to work with specific reagents,” Williams said.
“In some ways we would argue that the HCS market hasn’t lived up to its promise, and has sort of lagged in its uptake,” Williams added. “Part of that reason is the bulk of manufacturers focused specifically on their end of it and didn’t really pay attention to the applications required to drive the sales. When you think about the product, it’s not the instrumentation, the reagent by itself, or the informatics or bioapplication software. It’s that whole package together.”
Williams said that many of these HCS partnerships could become co-validation, co-development, and eventually, co-marketing agreements, although Invitrogen has no specific plans to enter the HCS instrumentation or software space beyond these partnerships.
“It could be everything from Invitrogen saying, ‘These reagents have been tested on X, Y, and Z platforms,” right through to co-marketing and co-development agreements,” he said. “We are in fact executing across the spectrum.”
Invitrogen’s first big splash in HCS is set to occur next week at DDT, Hung said, with poster and podium presentations about its LipidTOX and CellMask kits.
Although Invitrogen officially launched both products in April, the DDT showcase will be the first time it presents data supporting LipidTOX’s use in HCS, Hung said.
LipidTOX is based on the detection and characterization of phospholipidosis, or the intracellular accumulation of phospholipids and formation of lamellar bodies; and of steatosis, or the cytoplasmic accumulation of neutral lipid as lipid droplets or globules. Both of these processes have recently garnered increased attention from drug-discovery researchers as a way to detect early toxicity effects of drugs on cells.
“When we launched this assay in April, we said, ‘Here is a new dye that can provide multiplexing flexibility for reading phospholipid and neutral lipid metabolism,’ Hung said. “At that point, we didn’t have a lot of data to present to back this up as a validated assay.”
The DDT poster will display results of in-house validation research on the LipidTOX kits. Specifically, Invitrogen researchers compared LipidTOX assay results with the IC 50s of “10 or so” compounds with known toxicity profiles, Hung said.
Hung also said that LipidTOX will be the first commercially available assay kits for reading lipid metabolism-based cytotoxicity.
The second product Invitrogen recently launched is the CellMask line of reagents for staining the cytoplasm of an entire cell, as opposed to the nucleus or specific organelles.
The first step of any high-content screen, Hung explained, is to identify the object that needs to be studied – in this case, cells. Almost all commercial HCS platforms contain an image-analysis algorithm that does this based on nuclear staining.
“In some ways we would argue that the HCS market hasn’t lived up to its promise, and has sort of lagged in its uptake.”
This approach, however, has recently fallen out of favor a bit because it doesn’t always work, or at least it doesn’t always produce accurate results. Alternatively, many HCS instrumentation and software vendors have developed proprietary algorithms to identify cells based on full cytoplasmic staining, often in conjunction with nuclear staining. Hung mentioned Cellomics, Molecular Devices, and Evotec as vendors who offer algorithms for this purpose.
The purpose of the CellMask dyes is to facilitate image segmentation based on cytoplasmic staining, Hung and Williams said. The dyes come in red, blue, and deep red, and all have extremely sharp emission spectra that allow for multiplexing through additional labeling of sub-cellular structures, they said.
The red CellMask stain actually stains differently depending on its concentration, so HCS users can achieve an intensity that better fits the design of their particular instrument by allowing nuclear- or cytoplasm-based image segmentation, Invitrogen claims.
Down the Road
Future HCS developments from Invitrogen include “imaging-qualified” antibodies and HCS-optimized β-lactamase assays.
“We’ve heard customers that have imagers saying, ‘We can’t have all the antibodies. We have to have qualified antibodies to work with,’” Hung said. “We have about 500 to 1,000 immunostaining-qualified antibodies, and we’re going to roll that out very quickly and make it searchable for high-content screeners.”
Williams added that “at the minimum, they’d be qualified for an imaging application. But if they work for immunofluorescence, they’re almost guaranteed to work for HCS.
“We’re pulling out those that have been validated so we know they will work,” he continued. “Customers repeatedly say they need these to be validated for their specific applications. They want evidence. They say, ‘Show me that picture.’ They often see that some companies claim it, but there is a problem in that when they buy it, it doesn’t live up to the expectation.”
Invitrogen also said it plans to launch a kit for HCS based on its popular GeneBLAzer β -lactamase reporter technology for GPCR screening. Traditionally, this type of assay has been used with luminescent readouts and more frequently in high-throughput screening applications. But Hung said that it is applicable to HCS, as well.
“The beauty is that you can do multiple cell populations in the same well, and do differential displays, so to speak, for drug screens, and RNAi,” he said. “We have started to build data to support the application of β-lac assays in an HCS context.”
Hung and Williams did not give a specific timeline for the introduction of the new products.