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Phospho-aspirin-2 (MDC-22) inhibits estrogen receptor positive breast cancer growth both in vitro and in vivo by a redox-dependent effect.

Huang L, Wong CC, Cheng KW, Rigas B - PLoS ONE (2014)

Bottom Line: An upstream mediator of the signaling effects of PA-2 is RONS.PA-2 induced oxidative stress in vitro and in mice bearing MCF7 xenografts; its induction effect appears to be tumor-specific.Crucially, administration of N-acetylcysteine, a ROS scavenger, abrogated the effect of PA-2 on p53 acetylation and mitochondria translocation, thus identifying RONS as proximal molecules mediating the anticancer effect of PA-2.

View Article: PubMed Central - PubMed

Affiliation: Division of Cancer Prevention, Department of Medicine, Stony Brook University, Stony Brook, New York, United States of America.

ABSTRACT
Phospho-aspirin (PA-2) is a novel aspirin derivative that exhibits promising anticancer properties and is considerably safer than conventional aspirin. In this study, we investigated the chemotherapeutic efficacy of PA-2 in preclinical models of estrogen receptor positive (ER+) breast cancer and elucidated its mechanism of action. PA-2 inhibited the growth of ER+ cells more potently than aspirin in vitro, and exerted a triple cytokinetic effect that includes induction of apoptosis and cell cycle arrest as well as the inhibition of cell proliferation. PA-2 is highly efficacious in vivo, as treatment of established MCF7 xenografts with PA-2 induced tumor stasis (98.2% inhibition, p<0.01). PA-2 triggered the activation of p53-dependent apoptosis via two distinct mechanisms: 1) acetylation of p53 (at K373), which disrupts its interaction with its transcription repressor MDM2, and 2) translocation of p53 to the mitochondria leading to the dissipation of mitochondrial transmembrane potential (ΔΨ(m)). Consistent with these observations, both the RNAi-mediated knockdown of p53 and forced deactylation via HDAC1 over-expression attenuated the anticancer effect of PA-2 in MCF7 cells. An upstream mediator of the signaling effects of PA-2 is RONS. PA-2 induced oxidative stress in vitro and in mice bearing MCF7 xenografts; its induction effect appears to be tumor-specific. Crucially, administration of N-acetylcysteine, a ROS scavenger, abrogated the effect of PA-2 on p53 acetylation and mitochondria translocation, thus identifying RONS as proximal molecules mediating the anticancer effect of PA-2. In summary, our findings demonstrate that PA-2 is a promising antineoplastic compound against ER+ breast cancer, warranting further evaluation as an anticancer agent.

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Phospho-aspirin-2 induces oxidative stress.A:Left: Mitochondria superoxide was measured by MitoSOX Red dye after treatment of MCF7 cells with PA-2. Right: Nitric oxide levels was determined by DAF2 staining after treatment with PA-2. B: The levels of 15-F2t-isoprostane in 24-h urine of nude mice were determined using an enzyme-linked immunosorbent assay kit. Left: results from nude mice bearing MCF7 xenografts on day 3 (top) and day 10 (bottom). Right: results from nude mice bearing no xenografts on day 3 (top). The association between tumor volume and urinary 15-F2t-isoprostane levels in the nude mice from the xenograft study is shown (bottom).
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pone-0111720-g006: Phospho-aspirin-2 induces oxidative stress.A:Left: Mitochondria superoxide was measured by MitoSOX Red dye after treatment of MCF7 cells with PA-2. Right: Nitric oxide levels was determined by DAF2 staining after treatment with PA-2. B: The levels of 15-F2t-isoprostane in 24-h urine of nude mice were determined using an enzyme-linked immunosorbent assay kit. Left: results from nude mice bearing MCF7 xenografts on day 3 (top) and day 10 (bottom). Right: results from nude mice bearing no xenografts on day 3 (top). The association between tumor volume and urinary 15-F2t-isoprostane levels in the nude mice from the xenograft study is shown (bottom).

Mentions: RONS play a significant role in the mechanism of action of phospho-NSAIDs [24]. We determined the effect of PA-2 on RONS stress using MitoSOX Red (mitochondrial O2•-) and DAF2 (NO•). Compared to control, PA-2 1.5xIC50 increased mitochondrial O2•- by 58% in both MCF-7 and T-47D cells, and NO• by 42% in MCF7 and 75% in T-47D cells (Fig. 6A and figure S2A). To assess the effect of PA-2 on oxidative stress in vivo, we measured urinary 15-F2t-Isoprostane [25], [26]. In mice bearing MCF7 xenografts, PA-2 (500 mg/kg, i.p.) induced a significant increase in urinary F2-isoprostane as early as 3 days after initiation of the treatment. 15-F2t-isoprostane levels on day 3 were 33.1±6.8 ng/mg creatinine in controls and 13.5±3.7 ng/mg creatinine in the PA-2 group, representing a nearly 1.5-fold increase (p<0.05). A similar phenomenon was also observed on day 10 of treatment (p<0.05) (Fig. 6B). We also measured another RONS biomarker, 8-hydroxydeoxyguanosine (8-OHdG), in MCF-7 xenografted tumors and found the level of 8-OHdG significantly elevated (2.7-fold) in the treated group compared to its vehicle group (figure S2B). In contrast, PA-2 treatment failed to promote oxidative stress in the equivalent mice without MCF7 xenografts (Fig. 6B), suggesting that the induction of RONS by PA-2 is specific to the MCF7 xenografts while sparing the normal tissues. Furthermore, we observed a significant inverse correlation between the individual tumor sizes and the urinary 15-F2t-isoprostane levels (p<0.05), which implies that a stronger RONS response is associated with greater efficacy for PA-2.


Phospho-aspirin-2 (MDC-22) inhibits estrogen receptor positive breast cancer growth both in vitro and in vivo by a redox-dependent effect.

Huang L, Wong CC, Cheng KW, Rigas B - PLoS ONE (2014)

Phospho-aspirin-2 induces oxidative stress.A:Left: Mitochondria superoxide was measured by MitoSOX Red dye after treatment of MCF7 cells with PA-2. Right: Nitric oxide levels was determined by DAF2 staining after treatment with PA-2. B: The levels of 15-F2t-isoprostane in 24-h urine of nude mice were determined using an enzyme-linked immunosorbent assay kit. Left: results from nude mice bearing MCF7 xenografts on day 3 (top) and day 10 (bottom). Right: results from nude mice bearing no xenografts on day 3 (top). The association between tumor volume and urinary 15-F2t-isoprostane levels in the nude mice from the xenograft study is shown (bottom).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4219766&req=5

pone-0111720-g006: Phospho-aspirin-2 induces oxidative stress.A:Left: Mitochondria superoxide was measured by MitoSOX Red dye after treatment of MCF7 cells with PA-2. Right: Nitric oxide levels was determined by DAF2 staining after treatment with PA-2. B: The levels of 15-F2t-isoprostane in 24-h urine of nude mice were determined using an enzyme-linked immunosorbent assay kit. Left: results from nude mice bearing MCF7 xenografts on day 3 (top) and day 10 (bottom). Right: results from nude mice bearing no xenografts on day 3 (top). The association between tumor volume and urinary 15-F2t-isoprostane levels in the nude mice from the xenograft study is shown (bottom).
Mentions: RONS play a significant role in the mechanism of action of phospho-NSAIDs [24]. We determined the effect of PA-2 on RONS stress using MitoSOX Red (mitochondrial O2•-) and DAF2 (NO•). Compared to control, PA-2 1.5xIC50 increased mitochondrial O2•- by 58% in both MCF-7 and T-47D cells, and NO• by 42% in MCF7 and 75% in T-47D cells (Fig. 6A and figure S2A). To assess the effect of PA-2 on oxidative stress in vivo, we measured urinary 15-F2t-Isoprostane [25], [26]. In mice bearing MCF7 xenografts, PA-2 (500 mg/kg, i.p.) induced a significant increase in urinary F2-isoprostane as early as 3 days after initiation of the treatment. 15-F2t-isoprostane levels on day 3 were 33.1±6.8 ng/mg creatinine in controls and 13.5±3.7 ng/mg creatinine in the PA-2 group, representing a nearly 1.5-fold increase (p<0.05). A similar phenomenon was also observed on day 10 of treatment (p<0.05) (Fig. 6B). We also measured another RONS biomarker, 8-hydroxydeoxyguanosine (8-OHdG), in MCF-7 xenografted tumors and found the level of 8-OHdG significantly elevated (2.7-fold) in the treated group compared to its vehicle group (figure S2B). In contrast, PA-2 treatment failed to promote oxidative stress in the equivalent mice without MCF7 xenografts (Fig. 6B), suggesting that the induction of RONS by PA-2 is specific to the MCF7 xenografts while sparing the normal tissues. Furthermore, we observed a significant inverse correlation between the individual tumor sizes and the urinary 15-F2t-isoprostane levels (p<0.05), which implies that a stronger RONS response is associated with greater efficacy for PA-2.

Bottom Line: An upstream mediator of the signaling effects of PA-2 is RONS.PA-2 induced oxidative stress in vitro and in mice bearing MCF7 xenografts; its induction effect appears to be tumor-specific.Crucially, administration of N-acetylcysteine, a ROS scavenger, abrogated the effect of PA-2 on p53 acetylation and mitochondria translocation, thus identifying RONS as proximal molecules mediating the anticancer effect of PA-2.

View Article: PubMed Central - PubMed

Affiliation: Division of Cancer Prevention, Department of Medicine, Stony Brook University, Stony Brook, New York, United States of America.

ABSTRACT
Phospho-aspirin (PA-2) is a novel aspirin derivative that exhibits promising anticancer properties and is considerably safer than conventional aspirin. In this study, we investigated the chemotherapeutic efficacy of PA-2 in preclinical models of estrogen receptor positive (ER+) breast cancer and elucidated its mechanism of action. PA-2 inhibited the growth of ER+ cells more potently than aspirin in vitro, and exerted a triple cytokinetic effect that includes induction of apoptosis and cell cycle arrest as well as the inhibition of cell proliferation. PA-2 is highly efficacious in vivo, as treatment of established MCF7 xenografts with PA-2 induced tumor stasis (98.2% inhibition, p<0.01). PA-2 triggered the activation of p53-dependent apoptosis via two distinct mechanisms: 1) acetylation of p53 (at K373), which disrupts its interaction with its transcription repressor MDM2, and 2) translocation of p53 to the mitochondria leading to the dissipation of mitochondrial transmembrane potential (ΔΨ(m)). Consistent with these observations, both the RNAi-mediated knockdown of p53 and forced deactylation via HDAC1 over-expression attenuated the anticancer effect of PA-2 in MCF7 cells. An upstream mediator of the signaling effects of PA-2 is RONS. PA-2 induced oxidative stress in vitro and in mice bearing MCF7 xenografts; its induction effect appears to be tumor-specific. Crucially, administration of N-acetylcysteine, a ROS scavenger, abrogated the effect of PA-2 on p53 acetylation and mitochondria translocation, thus identifying RONS as proximal molecules mediating the anticancer effect of PA-2. In summary, our findings demonstrate that PA-2 is a promising antineoplastic compound against ER+ breast cancer, warranting further evaluation as an anticancer agent.

Show MeSH
Related in: MedlinePlus