Researchers in Granada, Spain have found that in malignant melanoma, extracellular vesicles called exosomes produced by cancer stem cells (CSCs) have a different molecular composition from those produced by differentiated tumour cells. Further, these molecular differences were found to be detectable in exosomes present in the blood of patients with malignant melanoma.
This finding could provide suitable biomarkers for the diagnosis and prognosis of malignant melanoma, according to the study’s authors.
Results of the study were published in the journal Molecular Oncology (Feb 2021; 15(2):407-428).
The study showed that the molecular composition of exosomes produced by CSCs is different from those released by differentiated tumour cells. To investigate this finding, researchers used a primary patient-derived malignant melanoma cell line enriched in CSCs. Both types of cells were cultivated in large quantities. The exosomes that they produced and released into the culture were isolated.
Once the properties and characteristics of both the cells and the exosomes they produced had been tested, the study’s authors conducted a metabolomic analysis.
After the molecules had been detected and extracted the investigators evaluated which molecules were found in the highest concentration in the exosomes of each cell type. The researchers then tentatively identified some lipidic metabolites distinctively present in exosomes of CSCs and differentiated tumour cells.
Following the same scientific approach, a similar study was conducted comparing the metabolomic profile of exosomes isolated from the blood of patients with malignant melanoma in different stages and exomes isolated from healthy individuals who acted as controls.
Investigators concluded that certain metabolites, including some of those previously identified in CSCs, were also present in different concentrations in exosomes isolated from blood from melanoma patients and healthy individuals. Using corresponding statistical models, these molecules and their different concentrations in blood made it possible to distinguish individuals with malignant melanoma from those without the disease. The authors note that this makes them suitable candidates for acting as potential diagnostic biomarkers.
The researchers note that the identification of some of the molecules, the complete characterization of those already tentatively identified and the replication of the study with a greater number of samples to validate and verify their clinical application as biomarkers all remain pending.
“Studies such as this constitute a new avenue for the discovery of cancer biomarkers aimed at improving early diagnosis, prognosis, and treatment-response prediction,” the study’s authors wrote. “Of course, these results can be extrapolated to many other tumours, in the quest to identify biomarkers that help us better understand the pathogenesis of these diseases and achieve personalized precision medicine.”