Co-expression of CD147 (EMMPRIN), CD44v3-10, MDR1 and monocarboxylate transporters is associated with prostate cancer drug resistance and progression

Abstract

Background: The aim of this study is to seek an association between markers of metastatic potential, drug resistance-related protein and monocarboxylate transporters in prostate cancer (CaP).

Methods: We evaluated the expression of invasive markers (CD147, CD44v3-10), drug-resistance protein (MDR1) and monocarboxylate transporters (MCT1 and MCT4) in CaP metastatic cell lines and CaP tissue microarrays (n=140) by immunostaining. The co-expression of CD147 and CD44v3-10 with that of MDR1, MCT1 and MCT4 in CaP cell lines was evaluated using confocal microscopy. The relationship between the expression of CD147 and CD44v3-10 and the sensitivity (IC(50)) to docetaxel in CaP cell lines was assessed using MTT assay. The relationship between expression of CD44v3-10, MDR1 and MCT4 and various clinicopathological CaP progression parameters was examined.

Results: CD147 and CD44v3-10 were co-expressed with MDR1, MCT1 and MCT4 in primary and metastatic CaP cells. Both CD147 and CD44v3-10 expression levels were inversely related to docetaxel sensitivity (IC(50)) in metastatic CaP cell lines. Overexpression of CD44v3-10, MDR1 and MCT4 was found in most primary CaP tissues, and was significantly associated with CaP progression.

Conclusions: Our results suggest that the overexpression of CD147, CD44v3-10, MDR1 and MCT4 is associated with CaP progression. Expression of both CD147 and CD44v3-10 is correlated with drug resistance during CaP metastasis and could be a useful potential therapeutic target in advanced disease.

Figure 1

Co-immunolabelling of CD147, CD44v3-10, MDR1, MCT1 and MCT4 in metastatic prostate cancer (CaP) cell lines. Representative confocal images of CD147 (green), CD44v3-10, MDR1, MCT1 and MCT4 (red) expression are shown. Merged images and red and green channels are shown separately. Membrane expression was found for CD147 and CD44v3-10 antibodies, whereas expressions of both membrane and cytoplasm were seen for MDR1, MCT1 and MCT4 antibodies. All immunostainings are more homogeneous. (A) CD147; (B) CD44v3-10; (C) MDR1; (D) MCT1; (E) MCT4; (F) colocalisation of CD147 with CD44v3-10; (G) colocalisation of CD147 with MDR1; (H) colocalisation of CD147 with MCT1; (I) colocalisation of CD147 with MCT1. Magnification: A–I × 400. The colour reproduction of the figure is available on the html full text version of the paper.

Figure 2

Expression of CD147, CD44v3-10, MDR1, MCT1 and MCT4 in prostate cancer (CaP) cell lines by western blotting. A representative western blot showing high levels of CD147, CD44v3-10, MDR1 (F4), MCT1 and MCT4 expression in PC-3-RX-DT2R and PC-3 cell lines, moderate expression in DU 145 cells and low or no expression in LNCaP and DuCaP cells. Equal loading is demonstrated with β-tubulin antibody in the bottom panel (lane 1: RX-DT2R, lane 2: PC-3, lane 3: DU145, lane 4: LNCaP-LN3. lane 5: DuCaP).

Figure 3

Dose response of metastatic prostate cancer (CaP) cell lines to docetaxel measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Drug-resistant and metastatic CaP cell lines treated with a range of concentrations of docetaxel (0.001–1000 nM, x axis) showed varying responses. The IC₅₀ value (50% normalised cell response) is related to the expression of CD147 and CD44v3-10. For example, the drug-resistant cell line, PC3-RX-DT2R, displays Grade 3 CD147 and CD44v3-10 expression, and an IC₅₀ of 44.7 nM (x axis); the drug-sensitive CaP cell line, DuCaP, displays Grade 0 CD147 and CD44v3-10 immunostaining and the lowest IC₅₀ of 4 nM (x axis) (n=3, mean±s.d.).

Figure 4

Expression of CD44v3-10, MDR1 and MCT4 in prostate cancer (CaP) tissue microarrays (TMAs). Representative images are shown of Grade 1 (weak) CD44v3-10 (A), MDR1 (E) and MCT4 (I); Grade 2 (medium) CD44v3-10 (B), MDR1(F) and MCT4 (J); and Grade 3 (strong) CD44v3-10 (C), MDR1(G) and MCT4 (K) immunostaining. No immunoreactivity is seen in non-specific negative controls for CD44v3-10 (D), MDR1 (H) and MCT4 (L). Brown colour indicates positive immunostaining. Insets indicate the typical areas of staining at high amplification. Magnification: A–L × 10; and insets × 40. The colour reproduction of the figure is available on the html full text version of the paper.

Figure 5

Co-immunolabelling of CD147, CD44v3-10, MDR1, MCT1 and MCT4 in primary prostate cancer (CaP) tissues (different tumours with a range of Gleason scores). Representative confocal images of CD147 and CD44v3-10 (green), CD44v3-10, MDR1, MCT1 and MCT4 (red) immunolabelling are shown. Merged images and red and green channels are shown separately. (A) CD147 and CD44v3-10 in high-grade CaP (Gleason score=8); (B) CD147 and MDR1 in high-grade CaP (Gleason score=8); (C) CD147 and MCT1 in low-grade CaP (Gleason score=6); (D) CD147 and MCT4 in high-grade CaP (Gleason score=8); (E) CD44v3-10 and MDR1 in high-grade CaP (Gleason score=9); (F) CD44v3-10 and MCT1 in high-grade CaP (Gleason score=8); (G) CD44v3-10 and MCT4 in high-grade CaP (Gleason score=8). CD147 immunolabelling is seen on epithelial cell membranes and stromal cells. CD44v3-10, MDR1, MCT1 and MCT4 immunostaining is predominantly epithelial. MCT4 localises mostly to basal epithelial cells and to lateral cell walls (magnification: A–G × 400). The colour reproduction of the figure is available on the html full text version of the paper.