EMT is an important mechanism of cancer progression and its regulation is crucial to understand for better treatment strategies. Androgens and estrogens are known regulators of PCa. The role of their receptors (AR, ERα, ERβ) in regulating EMT in PCa is still controversial. The aim was to assess possible links between levels of those receptors and N-cad as an EMT marker in PCa.
A training cohort of 28 radical prostatectomy samples was studied. N-cad neoexpression was used as an EMT marker. Double immunofluorescent staining was used. Sections were stained with primary rabbit polyclonal antibodies to N-cad and ERβ, mouse monoclonal to AR and ERα. Secondary antibodies were labeled with Alexa Fluor 488 and 555 dyes. Total staining score (TSS) for AR, ERα, ERβ was got by multiplication of semiquantitative assessments (0-3) of proportion of stained cells and staining intensity for each high power field with mean TSS calculated for a whole case. Weighed staining index (WSI) for N-cad took into account both proportion of positive cells per case and of them percentages of cells with weak, moderate and strong membranous staining.
Tumors were divided into N-cad negative (<10% positive cells) (n=18) and positive (>10%) (n=10). In N-cad positive cases AR TSS appeared to be significantly higher (4.59 vs. 2.81, pMann-Whitney=0.03). When N-cad WSI was correlated with AR and both ER subtypes mean TSS (in cancer epithelium or stroma), no correlation reached statistical significance, possibly due to relatively low number of cases, but, notably, correlations were negative for N-cad and ER subtypes both in stroma and epithelium, and positive for N-cad and epithelial AR (pSpearman>0.05).
AR expression in PCa was higher in cases with high numbers of EMT cells as defined by N-cad expression, assuming positive role of AR in EMT development in PCa. There was a tendency to negative correlation between both ERα and ERβ expression with N-cad, thus estrogens may down-regulate EMT in clinical samples. Relative levels of receptors may also be important, so more analyses in a larger sample cohort are ongoing to obtain data with possible predictive role to hormonal therapy efficacy.
M. Puchinskaya.
Belarusian Republican Foundation for Fundamental Research, Grant No. M14M-143, M19M-123.
M. Puchinskaya: Financial Interests, Personal, Invited Speaker: Roche.