Abstract 2012P
Background
CSC are a rare subpopulation capable of driving tumor progression and treatment resistance. Several markers of CSC have been described, none of them being able to readily define CSC. Combination of several molecules was shown promising in experimental works. dIF is a staining method enabling visualization and separate assessment of markers in tumor tissues. In the present work we used dIF to assess CSC markers expression in clinical PCa samples.
Methods
dIF method was used to stain a training cohort of 18 PCa samples. 4 μm thick slides of tissues obtained during radical prostatectomy were used for staining. CD44 and CD133 as were used as CSC markers, with corresponding primary antibodies (ThermoFischerScientific, 1:1000 dilution and Myltenyi Biotech 1:100), incubated overnight. For staining visualization secondary goat anti-mouse and goat anti-rabbit antibodies (ThermoFischerScientific, 1:200) conjugated with Alexa Fluor 488 and 555 probes were applied. Background autofluorescence was diminished by using incubation with Sudan black. Uterine cancer was used as a positive control for CD133 staining, and internal positive control for CD44. Slides were studied using Nikon 5500 microscope with appropriate filter cubes. Patterns of markers coexpression were studied.
Results
Both markers demonstrated predominantly membranous staining, though CD44 also stained cytoplasm in some cells. CD44 expression was seen in non-cancerous glands (NCG) as well as PCa. CD133 expression was extremely rare in PCa, with 61.1% of cases being negative for its expression. In the remaining cases only some glands (<5% of cells) stained positive with CD133 expression being seen on the luminal membrane of the gland (the same pattern as in uterine cancer). No direct coexpression of CD44 and CD133 was seen in this cohort.
Conclusions
The abundance of CSC markers staining in PCa vary with CD44 being positive in all cases and CD133 in only 38.9%. dIF is a good method of analyzing possible coexpression of 2 markers in tissue sections and will be used further to study CSC markers expression in a bigger set of PCa samples.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
M. Puchinskaya.
Funding
Belarusian Republican Foundation for Fundamental Research.
Disclosure
All authors have declared no conflicts of interest.