New alternatively spliced variant of prostate-specific membrane antigen PSM-E suppresses the proliferation, migration and invasiveness of prostate cancer cells

Abstract

Abstract. PSM-E is a newly discovered alternatively spliced variant of prostate-specific membrane antigen (PSMA). In the current study, its role on the proliferation, invasiveness and migration in prostate cancer cell lines was analyzed. PSM-E and PSMA (as a comparison) eukaryotic expression vectors pcDNA3.0/PSM-E and pcDNA3.0/PSMA were constructed, validated by RT-PCR and Western blotting, and PSMA/PSM-E overexpression PC-3 cell models were built. Gene interference was used to block PSMA and the expression of its splice variants in LNCaP cells. Three shRNA fragments were synthesized against PSMA, cloned into the vector pSilencer 2.1-U6-neo, their interference effect was evaluated by RT-PCR and Western blotting, and pSilencer 2.1-U6-neo-shRNA3 (named p-shRNA3) was chosen in further analyses. Growth curves were drawn to observe the proliferation change, which showed that PSM-E had the potential to suppress proliferation (P<0.05), but no significant change was observed in PSMA/PC-3 cells and in PSMA/PSM-E interfering LNCaP cells (P>0.05). Cross-river test showed that the migration speeds of PSM-E/PC-3 and PSMA/PC-3 were both significantly slower than the vector negative control, and faster in p-shRNA3 interfering LNCaP cells compared with its vector negative control (P<0.05), and no significant difference existed between PSM-E/PC-3 and PSMA/PC-3 (P>0.05). Transwell assay showed that the invasive cells of both PSMA/PC-3 and PSM-E/PC-3 were fewer compared to the vector negative control (P<0.05), and the invasive suppression effect of PSM-E was weaker than PSMA (P<0.05), and accordingly, invasiveness of interfering LNCaP cells was enhanced compared with the vector negative control (P<0.05). These results showed that PSM-E could suppress proliferation, migration and invasiveness of prostate cancer cells. Its suppression effect on cell proliferation is stronger compared to PSMA and the suppression effect on invasiveness is weaker than that of PSMA.

Prostate specific membrane antigen (PSMA) expression in primary gliomas and breast cancer brain metastases

“…This is not entirely unexpected as for prostate cancer evidence suggests that PSMA expression is greatest in high-grade, metastatic, and hormone-insensitive tumors [43]. Another possible basis for differential staining may relate to the observation that the FOLH1 (PSMA) gene generates several splice variants, including PSMA, PSME, PSM’, PSMA-C, PSMA-D, PSMAΔ6, and PSMAΔ18 [44,45]. Grade 1 through IV gliomas which exhibit different behavior and gene signatures, may also have differential expression of FOLH1 splice variants [46].…”

High uptake of 68Ga-PSMA and 18F-DCFPyL in the peritumoral area of rat gliomas due to activated astrocytes

“…However, no PSMA staining was observed in the peritumoral region. One possible explanation for this finding is the existence of different PSMA isoforms which are present in the brains of rats due to different splice variants of the FOLH1 gene [11,25,26] Vascular staining using an antibody against von Willebrand factor showed similar immunofluorescence intensity in the tumor and in the peritumoral area (Fig. 5, suppl.…”

High uptake of 68Ga-PSMA-HBED-CC and 18F-DCFPyL in the peritumoral area of rat gliomas due to activated astrocytes

“…However, no PSMA staining was observed in the peritumoral region. One possible explanation for this finding is the existence of different PSMA isoforms which are present in the brains of rats due to different splice variants of the FOLH1 gene [11,24,25] that are not recognized by the antibodies used. Little is known about PSMA isoforms in rats and information about specificity of the used antibodies for different rat PSMA isoforms is not available leaving this question open.…”