Journal List > Korean J Urol > v.50(1) > 1005380

Choi, Min, Choi, and Kang: Effects of α-Lipoic Acid on the Antioxidant System in Prostate Cancer Cells

Abstract

Purpose

Overproduction of lipid peroxidation byproducts and disturbances in the antioxidant defense system have been implicated in the pathogenesis of several diseases, including prostate cancer. Although several studies have investigated the level of lipid peroxidation and antioxidants in prostate cancer, there are no reports on α-lipoic acid (ALA) in prostate cancer. Here we assessed the effects of ALA on the antioxidant system in prostate cancer cells.

Materials and Methods

PC-3, LNCaP, and RWPE-2 cell lines were used in this study. Redox factor (Ref)-1 protein was measured by Western blot analysis after treatment with ALA. Real-time polymerase chain reaction (RT-PCR) was performed to detect superoxide dismutase (SOD)-1 and -2, catalase, and glutathione peroxidase (GSH-Px) mRNA expression.

Results

Ref-1 was expressed in the PC-3, LNCaP, and RWPE-2 cell lines. The expression of Ref-1 protein was increased after treatment with 125, 250, and 500μM ALA in the PC-3 (p<0.05) and LNCaP (p>0.05) cells compared with the RWPE-2 cells at 48 hours. In PC-3 cells, the mRNA expression of SOD-1, SOD-2, catalase, and GSH-Px decreased at 24 and 48 hours dose-dependently compared with that in RWPE-2 cells (p<0.05). The mRNA expression of SOD-2, catalase, and GSH-Px in LNCaP cell decreased at 48 hours dose-dependently (p<0.05).

Conclusions

The expression of Ref-1 protein and antioxidant enzymes changed after ALA exposure in prostate cancer cells. Our findings suggest that ALA affects the antioxidant system in prostate cancer cells and may be related to compensatory changes in the antioxidant defense system of the cells.

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Fig. 1.
The growth rate of the LNCaP cell line. *: inhibitory concentration (IC)50.
kju-50-72f1.tif
Fig. 2.
Effects of α-lipoic acid on the expression of redox factor (Ref)-1 protein in PC-3 and LNCaP prostatic cancer cells and RWPE-2 cells. (A) Ref-1 protein was isolated and Western blot analysis was performed. The bar diagrams (B) show means±SE of Ref-1 expression. *p<0.05, versus untreated control as analyzed by one-way ANOVA and Turkey’s multiple-comparison tests.
kju-50-72f2.tif
Fig. 3.
Effects of α-lipoic acid on the expression of superoxide dismutase (SOD)-1 mRNA in PC-3 (A) and LNCaP (B) prostatic cancer cells and RWPE-2 cells (C). The bar diagrams show means±SE of mRNA expression. *p<0.05, versus untreated control as analyzed by one-way ANOVA and Turkey’s multiple-comparison tests.
kju-50-72f3.tif
Fig. 4.
Effects of α-lipoic acid on the expression of superoxide dismutase(SOD)-2 mRNA in PC-3(A) and LNCaP(B) prostatic cancer cells and RWPE-2 cells (C). The bar diagrams show means±SE of mRNA expression. *p<0.05, versus untreated control as analyzed by one-way ANOVA and Turkey’s multiple-comparison tests.
kju-50-72f4.tif
Fig. 5.
Effects of α-lipoic acid on the expression of catalase mRNA in PC-3 (A) and LNCaP (B) prostatic cancer cells and RWPE-2 cells (C). The bar diagrams show means±SE of mRNA expression. *p<0.05, versus untreated control as analyzed by one-way ANOVA and Turkey’s multiple-comparison tests.
kju-50-72f5.tif
Fig. 6.
Effects of α-lipoic acid on the expression of glutathione peroxidase mRNA in PC-3 (A) and LNCaP (B) prostatic cancer cells and RWPE-2 cells (C). The bar diagrams show means±SE of mRNA expression. *p<0.05, versus untreated control as analyzed by one-way ANOVA and Turkey’s multiple-comparison tests.
kju-50-72f6.tif
Table 1.
PCR primer
Sense primer Anti-sense promer Product
SOD 1 5′-GTG TGG GGA AGC ATT AAA GG-3′ 5′-ACA TTG CCC AAG TCT CCA AC-3′ 170-bp
SOD 2 5′-GTT GGC CAA GGG AGA TGT TA-3′ 5′-AGT CAC GTT TGA TGG CTT CC-3′ 158-bp
Catalase 5′-TCT GGA GAA GTG CGG AGA TT-3′ 5′-AGT CAG GGT GGA CCT CAG TG-3′ 190-bp
GSH-Px 5′-AGC CCA ACT TCA TGC TCT TC-3′ 5′-CCC ACC AGG AAC TTC TCA AA-3′ 193-bp
GAPDH 5′-CGT CTA GAA AAA CCT GCC AA-3 5′-TGA AGT CAG AGG AGA CCA CC-3′ 118-bp

PCR: polymerase chain reaction, SOD: superoxide dismutase, GSH-Px: glutathione peroxidase, GAPDH: glyceraldehyde 3-phosphate dehydrogenase

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