Researchers say that a new imaging technique tested on mice is able to identify breast cancer subtypes accurately, as well as detecting early treatment response. This is according to a new study published in the journal Cancer Research.
The research team from Vanderbilt University in Tennessee says the imaging technique – optical metabolic imaging (OMI) – could eventually be used in endoscopes for live imaging of human cancers.
When human cells experience metabolic activity in order to produce energy, this activity is altered in cancer cells, the researchers explain. Metabolic activity in cancer cells change when they are treated with anticancer drugs. The team set out to see whether these changes could be detected using OMI.
Two molecules involved in cellular metabolism – nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) – naturally emit fluorescence when they are exposed to certain forms of light.
The researchers used a custom-built, multiphoton microscope alongside a titanium laser that triggered fluorescence in NADH and FAD. Using filters to “isolate” the fluorescence emitted by the molecules, the researchers were able to measure the ratio of them as “redox ratio.”
The researchers analyzed normal and cancerous cells under the microscope and found that the OMI technique showed “distinct signals” for both cell types.
Furthermore, OMI was also able to differentiate between estrogen receptor-positive, estrogen receptor-negative, HER2-positive, and HER2-negative breast cancer cells.
The researchers then monitored the effect of trastuzumab – an anti-HER2 antibody – on three breast cancer cell lines that respond differently to the drug.
Results showed a significant reduction in redox ratios of drug-sensitive cells following the treatments, but the ratios were unaffected in resistant cells.
The team then grew human breast tumors in live mice, and treated some of the mice with trastuzumab.
Using the OMI technique on the mice, the researchers could see a difference in response between tumors that were sensitive to the drug, and those that were resistant 2 days following the first dose of the drug.
The researchers note that in comparison, the standard imaging technique – FDG-PET – was not able to measure any response differences throughout the full 12-day experiment.
Alex Walsh, a graduate student of the Department of Biomedical Engineering at Vanderbilt University and study author, says:
“We have shown that optical metabolic imaging enables fast, sensitive and accurate measurement of drug action.
Importantly, OMI measurements can be made repeatedly over time in a live animal, which significantly reduces the cost of these preclinical studies.”
“Cancer drugs have profound effects on cellular energy production, and this can be harnessed by OMI to identify responding cells from non-responding cells,” she continues.
“We are hoping to develop a high-throughput screening method to predict the optimal drug treatment for a particular patient.”
Medical News Today recently reported that doctors in Boston are investigating the possibility of nipple injections to treat breast cancer.