CSCs, specifically their involvement in tumor progression and chemoresistance, represents one of the cornerstones of current cancer research. CSCs autofluorescence analysis has proven to be an accurate method to detect these cells in tumor tissues, offering an ideal setting to study the prognostic and predictive implications of this marker. More importantly, it also offers a new scenario for the development of personalized screening platforms, which could be widely universalized in the hospital setting. However, a straightforward and reproducible model for the identification and isolation of autofluorescent CSCs is still lacking.
Fresh tissues from 97 resected tumors were analyzed over 24 months. The percentage of CSCs in primary tumors was analyzed using autofluorescence, the result of Riboflavin accumulation in discrete cytoplasmic vesicles over expressing the ATP-dependent transporter ABCG2. These results were correlated with the established CSCs markers CD133 and CD90. Fumitremorgine C (FTC), a specific inhibitor of ABCG2, was used to verify the specificity of the autofluorescence observed.
Autofluorescent cells (AC) in the epithelial cell compartment (EpCAM+) of the tumors analyzed were identified in 60% of the samples, primarily in gastrointestinal tumors (e.g. colon, gastric, rectal). AC also co-expressed other established CSC markers, such as CD90. Autofluorescence disappeared when tumoral cells were incubated with FTC confirming that the autofluorescence observed was ABCG2-dependent.
CSCs can be efficiently identified and isolated from gastrointestinal tumors using autofluorescence. The simplicity of this method would allow for its applicability to the broader scientific community in order to investigate the behaviour of CSCs in tumor progression and drug resistance. Moreover, upon their isolation, AC could be used in screening platforms to assess the chemoresistance of CSCs, thus allowing for the development of new molecular targeted therapies.
Clinical trial identification
Legal entity responsible for the study
Hospital Universitario Infanta Sofía.
Has not received any funding.
All authors have declared no conflicts of interest.