Inhibition of LDHA suppresses tumor progression in prostate cancer

Abstract

A key hallmark of cancer cells is their altered metabolism, known as Warburg effect. Lactate dehydrogenase A (LDHA) executes the final step of aerobic glycolysis and has been reported to be involved in the tumor progression. However, the function of LDHA in prostate cancer has not been studied. In current study, we observed overexpression of LDHA in the clinical prostate cancer samples compared with benign prostate hyperplasia tissues as demonstrated by immunohistochemistry and real-time qPCR. Attenuated expression of LDHA by siRNA or inhibition of LDHA activities by FX11 inhibited cell proliferation, migration, invasion, and promoted cell apoptosis of PC-3 and DU145 cells. Mechanistically, decreased Warburg effect as demonstrated by reduced glucose consumption and lactate secretion and reduced expression of MMP-9, PLAU, and cathepsin B were found after LDHA knockdown or FX11 treatment in PC-3 and DU145 cells. Taken together, our study revealed the oncogenic role of LDHA in prostate cancer and suggested that LDHA might be a potential therapeutic target.

Keywords: LDHA; Progression; Prostate cancer; Warburg effect.

Figures

Fig. 1

Altered expression of LDHA was observed in PC. a Representative images of the LDHA expression in benign prostate hyperplasia (BPH) and pancreatic cancer (PC); scale bar: 50 μm. b Increased LDHA protein expression in 11 BPH tissues and 74 PC tissues were detected by immunohistochemistry. c Increased LDHA mRNA expression in 12 BPH tissues and 20 PC tissues were detected by quantitative real-time PCR. d LDHA expression in Singh prostate grouped by normal prostate gland (1, n = 50) and prostate cancer (2, n = 52) derived from Oncomine database. e LDHA expression in Tomlins prostate grouped by no value (0, n = 27), BPH (1, n = 11), prostatic intraepithelial neoplasia (2, n = 13), and prostate cancer (3, n = 49) derived from Oncomine database. g Expression level of LDHA in four PC cell lines, tubulin amounts were measured as a control

Fig. 2

Silencing of LDHA by siRNA inhibits cell proliferation, migration, and invasion and increases cell apoptosis in vitro. a The expression level of LDHA was detected by Western blotting in PC-3 and DU145 cells after three different siRNA treatment. b Cell viability of PC-3 and DU145 cells was measured by CCK8 after LDHA knockdown. Increased cell apoptosis ratio (c) and caspase-3/7 activity (d) were observed after LDHA knockdown. Cell migration (e) and invasion abilities (f) of PC-3 and DU145 cells were decreased after LDHA was silenced. si-Ctrl versus si-LDHA-3; *P < 0.05; **P < 0.01; ***P < 0.001

Fig. 3

Inhibition of LDHA by FX11 suppresses cell proliferation, migration, and invasion and increases cell apoptosis in vitro. a The protein level of LDHA in PC-3 cells after FX11 treatment. b Cell viability of PC-3 and DU145 cells was measured by CCK8 after FX11 treatment. Increased cell apoptosis ratio (c) and caspase-3/7 activity (d) were observed after FX11 treatment. Cell migration (e) and invasion abilities (f) of PC-3 and DU145 cells were decreased after FX11 treatment. Ctrl versus FX11; *P < 0.05; **P < 0.01; ***P < 0.001

Fig. 4

Inhibition of LDHA by siRNA or FX11 reprograms glucose metabolism. Relative lactate secretion after LDHA was knockdown (a) or FX11 treatment (b). Relative glucose consumption after LDHA was knockdown (c) or FX11 treatment (d). *P < 0.05; **P < 0.01; P values were calculated by the Student’s t test

Fig. 5

Inhibition of LDHA by siRNA or FX11 downregulates proteases involved in extracellular matrix degradation and tumor metastasis. Relative expression of MMP-9, PLAU, and cathepsin B after LDHA was knockdown (a) or FX11 treatment (b). c Schematic illustration of the proposed metabolic consequences induced by LDHA in PC