Abstract 26P
Background
EMT is a process important for malignant tumor metastasis and drug resistance. Various molecules have been studied as markers of EMT, but still none of them can readily define cells more capable of aggressive behaviour. Expression of various markers differs in cancer cells. Several experimental works have shown that simultaneous presence of both epithelial and mesenchymal markers is important for metastasis. We aimed to assess coexpression of E- and N-cadherins (cad) in PCa cells as a sign of EMT.
Methods
A training cohort of PCa samples was stained using double immunofluorescence (dIF) technique. 4 μm thick slides of tissues obtained during radical prostatectomy were used for staining. Primary antibodies to E-cad (BioGenex, 1:150 dilution) and N-cad (ThermoFischerScientific, 1:1500) and secondary antibodies (ThermoFischerScientific, 1:200) conjugated with Alexa Fluor 488 and 555 probes were applied. Slides were studied using Nikon 5500 microscope. Patterns of markers coexpression were assessed.
Results
Staining pattern of both cadherins was predominantly membranous with entire membranes being stained in cancer cells, in some cases cytoplasmic staining was also seen. E-cad staining was homogenous and present in both non-cancerous glands (NCG) and PCa (down-regulated to different extent in the latter). Opposingly, N-cad staining was very patchy, the marker being present in only few cells, also both in PCa and NCG, in some cases staining in the latter was even more prominent. Either entire gland or only some cells were stained. Staining intensity was strong to moderate. As there were no cells with E-cad absence, cadherins co-expression was seen in all N-cad-positive cells and the percentage of coexpressing cells was, correspondingly, the same as N-cad+ cells. No significant signs of stronger E-cad down-regulation in N-cad positive cells compared to adjacent N-cad-negative was noted. Coexpression of cadherins was seen in <5% of PCa cells in 75% of cases.
Conclusions
Coexpression of epithelial and mesenchymal cadherins in PCa is dependent on N-cad expression that was present in a limited number of cells. It can be speculated that these rare cells are the main source of further PCa progression and metastasis.
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.