Ouabain induces apoptotic cell death in human prostate DU 145 cancer cells through DNA damage and TRAIL pathways

Abstract

Ouabain, a cardiotonic steroid and specific Na+/K+‐ATPase inhibitor, has a potential to induce cancer cell apoptosis but the mechanisms of apoptosis induced by ouabain are not fully understand. The aim of this study was to investigate the cytotoxic effects of ouabain on human prostate cancer DU 145 cells in vitro. Cell morphological changes were examined by phase contrast microscopy. Cell viability, cell cycle distribution, cell apoptosis, DNA damage, the production of ROS and Ca2+, and mitochondrial membrane potential (ΔΨm) were measured by flow cytometry assay. Results indicated that ouabain induced cell morphological changes, decreased total cell viability, induced G0/G1 phase arrest, DNA damage, and cell apoptosis, increased ROS and Ca2+ production, but decreased the levels of ΔΨm in DU 145 cells. Ouabain also increased the activities of caspase‐3, ‐8, and ‐9. Western blotting was used for measuring the alterations of apoptosis‐associated protein expressions in DU 145 cells and results indicated that ouabain increased the expression of DNA damage associated proteins (pATMSer1981, p‐H2A.XSer139, and p‐p53Ser15) and ER‐stress‐associated proteins (Grp78, ATF6β, p‐PERKThr981, PERK, eIF2A, GADD153, CaMKIIβ, and caspase‐4) in time‐dependently. Furthermore, ouabain increased apoptosis‐associated proteins (DR4, DR5, Fas, Fas Ligand, and FADD), TRAIL pathway, which related to extrinsic pathway, promoted the pro‐apoptotic protein Bax, increased apoptotic‐associated proteins, such as cytochrome c, AIF, Endo G, caspase‐3, ‐8, and ‐9, but reduced anti‐apoptotic protein Bcl‐2 and Bcl‐x in DU 145 cells. In conclusion, we may suggest that ouabain decreased cell viability and induced apoptotic cell death may via caspase‐dependent and mitochondria‐dependent pathways in human prostate cancer DU 145 cells.

Ouabain Exhibited Strong Anticancer Effects in Melanoma Cells via Induction of Apoptosis, G2/M Phase Arrest, and Migration Inhibition

“…Furthermore, multiple studies showed that ouabain exerted anticancer effects on lung, prostate, liver, breast cancer cells via anti-proliferative effects, autophagic cell death, apoptosis, and migration inhibition. [14][15][16]18 Here, our study demonstrated that ouabain induced significant morphological changes and proliferation inhibition in melanoma cells. Inconsistently, Ouabain induced significant cell apoptosis in A375 cells rather than SK-Mel-28 cells.…”

“…Furthermore, the potential anticancer effects of ouabain have been widely reported in various cancers via autophagic cell death, apoptosis, and migration inhibition. [14][15][16][17] However, no research regarding the effects of ouabain on melanoma cells were reported, even though ouabain had been used as a cardiotonic drug for many years. In our work, we evaluated the effects of ouabain on the proliferation, apoptosis induction, cell cycle distribution, and the migration of melanoma cells, and performed transcriptome sequencing to determine the possible mechanisms for its pharmacological activity, which prompted ouabain might be a potential anticancer agent for the clinical treatment of melanoma.…”

Metabolomic approach to characterize the metabolic phenotypes and varied response to ouabain of diffuse large B-cell lymphoma cells

“…These data indicated that hypoxanthine and guanine degradation were increased or hypoxanthine and guanine synthesis were blocked in Su-DHL4 cells, while level of NADPH for anti-oxidant was elevated in OCI-Ly3 cells. It is well documented that enhanced ROS level is related to apoptosis (Figure 5(A)) [35][36][37][38]. As showed, ROS generation was significantly elevated in Su-DHL4 cells with ouabain rather than in OCI-Ly3 cells (Figured 5(B)).…”

“…The catabolism of hypoxanthine and guanine into uric acid produces much ROS [33,34]. Moreover, previous studies showed that ouabain induced cell apoptosis by promoting ROS generation [35][36][37][38]. So we speculated that different antioxidant capacity may contribute to differential apoptosis rate induced by ouabain.…”

Anti-Gastric Cancer Effect of Purified Omphalia Lapidescens Protein via Regulating the JAK/STAT3 Signaling Pathway

“…phase, G1 phase, S phase and G2 phase [36]. It is reported that cell death is related to DNA damage and degradation [37]. Hence, cells in Sub-G1 phase were regarded as dead cells.…”