NEW YORK – A group led by researchers at Johns Hopkins University has launched a startup called RecurX Bio to commercialize a microfluidic device, originally built to predict the risk of breast cancer metastasis, and develop a variety of assays for breast cancer and glioblastoma (GBM)-based diagnostic, prognostic, and treatment response applications.
The team published a proof-of-principle study this week that highlighted the device's ability help to predict the clinical outcomes of GBM patients.
GBM is an aggressive type of cancer that develops in a patient's brain or spinal cord, where it can form from mutated astrocyte cells and often occurs in older patients. Clinicians usually identify the tumor through a neurological exam or image-based detection such as an MRI.
RecurX Bio's device leverages a technology it calls "microfluidic assay for quantification of cell invasion" (MAqCI) that contains two parallel seeding and collection channels connected to Y-shaped microchannels that mimic aspects of a patient's in vivo microenvironment. A feeder channel bifurcates into two narrow channels to track cancer cell movement.
"We extended the use of the assay to the glioblastoma space because it is the [deadliest] cancer type, and it can invade and proliferate within the brain," JHU professor and study senior author Konstantinos Konstantopoulos explained. "We wanted to develop an assay that can be used for several solid cancers, but we were happy to spot the relative abundance of migratory cells in glioblastoma patients."
While the tool's capabilities have mostly remained the same since Konstantopoulos originally used it for predicting breast cancer metastasis risk, his team has now included a parameter that he said is more appropriate for cells from tumors like GBM, as opposed to epithelial cells. The group believes the assay's microfluidic channels can specifically mimic parts in the brain and track the behavior of GBM cells.
In the study, published on Monday in Nature Biomedical Engineering, Konstantopoulos and his colleagues adapted the MAqCI device by quantifying cell migration and other parameters to subcategorize patients with GBM.
In a retrospective cohort of 28 GBM patients, Konstantopoulos' team initially injected cells into the MAqCI device and classified them as either "lowly" or "highly" motile cells depending on their migrations status through the feeder channels.
To predict the patients' PFS and recurrence, Konstantopoulos' team created a MAqCI composite score between 0 and 1 that incorporated three cellular parameters: the cells' ability to squeeze into narrow spaces, their migratory behavior, and their proliferation rates.
The researchers found that the retrospective composite MAqCI score had an overall sensitivity of 84 percent and a specificity of 89 percent in the 28-patient cohort.
Although the percentage of highly motile KI-67+ (a protein marker strongly associated with tumor cell proliferation and growth) cells identified using MAqCI negatively correlated with patient survival, Konstantopoulos noted there was no significant correlation between percentage of KI-67+ cells in the heterogeneous GBM population and patient survival.
In addition to GBM patient survival, the study authors saw that they could use MAqCI measurements to predict a patient's time to recurrence.
Alfredo Quinones-Hinojosa, study senior author and chair of neurosurgery at Mayo Clinic, said that the MAqCI device helped the team understand the migratory potential and growth patterns of GBM, which he described as the "go and growth" behavior of cancers.
The team also prospectively used MAqCI to predict the PFS and overall survival in a cohort of five GBM patients. Performing RNA sequencing on a patient's isolated highly motile cells compared to unsorted bulk cells, the team identified 17 upregulated genes whose individual expression patterns correlated with overall survival. Using the genes to establish a composite MAqCI score for each patient, the team saw that higher scores indicating a worse overall survival correlated with the patients that had a poor prognosis.
"This technology has the potential to expand the use of RNA-sequencing in a manner that hasn't been explored in the past because we managed to isolate the migratory cells," Konstantopoulos said. "We are able to collect cells and process them for proteogenomic studies."
Konstantopoulos pointed out that MAqCI allows his team "the unique ability to assess the proliferative capabilities of GBMs," to sort bulk total cancer cell population into separate subpopulations based on the cells' motility, and independently assess their KI-67+ data based on the cells that enter the device's branch channels.
"Notably, if we just quantify the percentage of Ki-67+ cells for the unsorted bulk cell population … we fail to achieve any correlation to patient survival," the study authors noted. "By contrast, the percentage of Ki-67+ cells for the highly motile cell subpopulation significantly correlated to patient survival, thereby showcasing the importance of MAqCI as a sorting device."
Quinones-Hinojosa highlighted that researchers in prior studies measured the GBM cell growth or migratory movement but struggled to analyze both parameters at the same time.
"Before, we were using a shotgun [sequencing] approach to look at the [mutation] genotype and using IDH1 mutant wild types to predict behavior," Quinones-Hinojosa said. "Now, we're selectively isolating the cells that are the deadliest, taking them away, and figuring out what's special about the cells."
However, Konstantopoulos acknowledged the study's results was limited by its sample size in both the retrospective and prospective cohorts. The researchers have since begun recruiting additional GBM patients to validate the device, with the goal to collect samples from 100 glioblastoma patients within the next two years.
Konstantopoulos' team currently holds two patents from the US Patent and Trademark Office to apply MAqCI for both breast cancer- and GBM-based applications. The group has also filed for IP with the USPTO related to using MAqCI for additional GBM-related applications.
Konstantopoulos cofounded RecurX Bio with CEO Cindy Clark and retired Becton Dickinson senior VP Charles Goldstein in July to commercialize an assay based on the MAqCI system.
While RecurX Bio is currently located at JHU's FastForward incubator, Konstantopoulos' group is currently working on plans to build a CLIA-certified, College of American Pathologists-accredited lab in Baltimore. With its license to the MAqCI technology from JHU, the firm envisions developing laboratory-developed tests based on the microfluidic device for a full suite of breast cancer and GBM-based applications as well as other cancers.
For example, RecurX Bio will initially apply MAqCI to develop a laboratory-developed test that will select the most effective US Food and Administration-approved drugs for personalized cancer therapies for solid cancer types.
"Our analysis will not only be limited to drugs for breast cancer but will also include all FDA-approved drugs for all types of solid cancer," Konstantopoulos said. "With our technology, we may find out that a particular drug will be effective for person A, but not for person B."
The firm then expects to develop an LDT using the platform for diagnosing and monitoring cancer patients, followed by a companion tool for selecting patients in clinical trials.
In addition, RecurX Bio aims to create an assay using MAqCI to discover new therapeutic targets by isolating GBM cells and performing single-cell analysis using RNA-sequencing, which Konstantopoulos envisions will aid pharmaceutical firms in drug development.
Konstantopoulos said that RecurX Bio will apply for Small Business Innovation Research grants, where the firm could receive $1 to $2 million. He noted that his lab just received a translational grant from the state of Maryland for $165,000 for breast cancer research.
The firm is also collaborating with JHU and the University of Maryland to validate the initial assay on breast cancer patient samples.
"In addition to our connections with Mayo Clinic, we are trying to expand through academic institutions and share our device so that we can test as many patients as possible," Konstantopoulos added.