NEW YORK (GenomeWeb) – Quanterix's single-molecule array technology can be applied to quantify proteins in single cancer cells, a new study from the firm's scientific founder suggests.
In proof-of-concept research, scientists from Tufts University used the Simoa HD-1 Analyzer to detect high and low levels of prostate-specific antigen in LNCaP cell lines. Led by co-first authors Stephanie Schubert and Stephanie Walter and senior author David Walt, a professor at Tufts and scientific founder of Quanterix, the scientists published their study last month in Analytical Chemistry.
For Lexington, Massachusetts-based Quanterix, the study points to another potential research use for the Simoa HD-1 Analyzer.
"There's pretty profound interest in this," Quanterix CEO Kevin Hrusovsky told GenomeWeb. "What we're doing is showcasing the ability for Simoa, in an automated way, to take single cells and count the number of proteins in that cell."
Using a low passage LNCaP cell line (LNCaPa) and a similar, over subcultured cell line that had undergone genetic drift (LNCaPb), the researchers showed that average intracellular PSA protein levels differed by a factor of approximately 30.
LNCaPa cells averaged a PSA concentration per cell of 1.79 microM, or 53.7 micrograms/mL, while LNCaPb averaged .06 microM, or 1.2 micrograms per mL, assuming cell volume of 2 picoliters, the authors said.
The Tufts researchers highlighted that they were able to do protein quantification without the need for "genetic engineering, fluorescent labeling, complicated microfluidic platforms, or rigorous time-consuming data analysis technologies," adding that they were able to achieve throughput of 100 single cell samples in less than 3 hours at a sensitivity of .004 pg/ML or 12,000 PSA molecules per 140 micrograms of cell lysate.
Hrusovsky offered that the sensitivity described puts Simoa's protein detection capabilities on par with its DNA sensitivity.
For him, it's an indication that single-cell proteomics could accelerate growing interest in the company's technology.
In fiscal year 2015, Quanterix's revenues more than doubled to $12 million, from $5 million in 2014, Hrusovsky said, partly due to the firm's Simoa Accelerator program. "We're seeing bigger projects. The number of projects isn't doubling, but increasing size of projects is part of our growth," he said.
He estimated that 95 percent of the revenue came from life sciences revenue as opposed to diagnostics, and within the life sciences revenue, 60 percent came from the pharmaceutical and biotech markets, while the remaining 40 percent came from academia and government.
While Hrusovsky doesn't expect the new single-cell paper to drive growth in pharma and biotech, he said it could help make Simoa much more attractive to the academic market.
"I'm encouraging our sales force to ensure that as we reach out to the oncology world that they understand the combination of these papers could catalyze a lot of innovative thinking," he said.
"You can start to do the math. If we've now demonstrated Simoa can be used on single cells and proven in previous papers that we can do DNA and mRNA, what could this mean for single-cell biology across all molecular structures using Simoa?"
He suggested that Simoa could now compete with several existing protein-counting technologies.
Immuno-qPCR was the most similar, Hrusovsky said. The Tufts researchers noted in the paper that a previous study had found roughly comparable counts of PSA molecules per LNCaP cells. But Hrusovsky said that PCR had inherent biases that Simoa didn't. "We're doing it without PCR, which makes it much more accurate" and reproducible, he said, adding that Simoa was an automated technology.
He also pointed to Fludigim's mass cytometry offerings as potential competition.
With the new paper, Hrusovsky said Quanterix can point to literature demonstrating Simoa's ability to detect DNA, RNA, microRNAs, and now proteins. "Scientists can be looking at any molecular structure with exquisite reproducibility and sensitivity," he said. As long as scientists have the antibodies to capture their protein of interest, they can use Simoa, said Hrusovsky, adding that Quanterix offers a homebrew assay kit as well as assay design services.
"I can' wait to see when they look at other proteins," he said.
While diagnostics is not a major focus at the company right now, Hrusovsky suggested there could be growth in that market down the road. For example, Quanterix has signed an agreement with BioMerieux for diagnostic applications of the Simoa technology.
Point-of-care diagnostics could be one application because of the sensitivity, Hrusovsky suggested. "Can you get info from a finger prick like Theranos claimed they could do?" he asked. "What company is in better place to get that than a company that has the sensitivity we have? We can take samples and dilute them 100 times," he said.
However, if there is any value that would come from diagnostic applications, it would come in 2017 and not 2016, Hrusovsky said.