CD147 modulates autophagy through the PI3K/Akt/mTOR pathway in human prostate cancer PC-3 cells - PubMed (original) (raw)

CD147 modulates autophagy through the PI3K/Akt/mTOR pathway in human prostate cancer PC-3 cells

Fang Fang et al. Oncol Lett. 2015 Mar.

Abstract

The multifunctional glycoprotein cluster of differentiation (CD)147 is highly expressed on the cell surface of the majority of cancer cells, and promotes tumor invasion, metastasis and growth. However, the role of CD147 in autophagy has not yet been explored in prostrate cancer cells. In the present study, prostate cancer PC-3 cells were cultured under starvation conditions, and the expression level of CD147 gradually increased. Therefore, RNA interference was used to inhibit CD147 expression, in order to investigate the biological role of this glycoprotein in autophagy progression. Autophagic activity was monitored by the changes in green fluorescent protein-light chain 3 (GFP-LC3) location and the expression of the autophagy-associated protein LC3-II. It was found that downregulation of CD147 significantly promoted GFP-LC3 puncta formation and the expression of LC3-II. Furthermore, the levels of phosphorylated serine/threonine protein kinase B (p-Akt) and phosphorylated mammalian target of rapamycin (p-mTOR) were significantly decreased, and the level of LC3-II was inversely associated with levels of p-Akt and p-mTOR in cells with downregulated expression of CD147. The results of a trypan blue exclusion assay revealed that starvation-induced cell death was increased in PC-3/shCD147 cells compared with control PC-3/Scramble cells (37.7±6.4 vs. 21.7±5.5%). Together, these results indicate that CD147 may be important in the inhibition of autophagy via the PI3K/Akt/mTOR pathway, which prevents cell death from unrestrained autophagy.

Keywords: PI3K/Akt/mTOR pathway; autophagy; cluster of differentiation 147; prostate cancer.

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Figures

Figure 1

Figure 1

Change in CD147 expression in starvation-induced autophagy in PC-3 cells. CD147 expression was assayed by western blotting. *P<0.05 vs. 0 h, **P<0.01 vs. 0 h. CD147, cluster of differentiation 147.

Figure 2

Figure 2

CD147 expression was detected in transfected cells. (A) Reverse transcription-polymerase chain reaction analysis of the CD147 gene level. (B) Western blot analysis of the CD147 protein level. CD147, cluster of differentiation 147; shCD147, short hairpin CD147 RNA.

Figure 3

Figure 3

CD147-mediated inhibition of starvation-induced autophagy in PC-3 cells. (A) The autophagosomes in the cells were visualized by observing LC3 puncta under fluroesence microscopy. (B) Quantitated levels of LC3-II from western blot analysis. *P<0.05, **P<0.01 vs. control cells. CD147, cluster of differentiation 147; shCD147, short hairpin CD147 RNA; GFP, green fluorescence protein; LC3, light chain 3.

Figure 4

Figure 4

Analysis of the signaling pathway involved in the downregulation of atophagy by CD147. The cells were cultured for 12 h in EBSS medium with or without 20 μM LY294002. Western blot analysis was performed to observe the expression level of p-Akt, p-mTOR and LC3-II. p-Akt, phosphorylated protein kinase B; p-mTOR, phosphorylated mammalian target of rapamycin; LC3, light chain 3; CD147, cluster of differentiation 147; shCD147, short hairpin CD147 RNA.

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