Activation of TAO2 Kinase by Arsenic Trioxide in Leukemic Cells

Abstract Arsenic Trioxide (As2O3) has major efficacy in the treatment of acute promyelocytic leukemia (APL), but its use in other malignancies is limited by the need for high intracellular concentrations to induce apoptosis. Prior work in our laboratory has demonstrated that the p38 MAP kinase (MAPK) pathway is activated following treatment of cells with As2O3 and exhibits negative regulatory effects on As2O3-induced apoptosis and growth suppression. In the current study, we sought to identify upstream effector mechanisms by which the p38 pathway is activated by As2O3 in leukemic cells. We found that the MAPK kinase kinase TAO2 (thousand and one amino acid protein kinase 2) is phosphorylated on Ser181 after treatment of NB4, NB4.306, and U937 cells with arsenic. Such phosphorylation was rapid, occurring as early as after 5 minutes of As2O3 treatment. In addition, our data indicate that such phosphorylation occurs downstream of As2O3-induced redox reactions, as demonstrated by increased phosphorylation in cells pretreated with the oxidizing agent buthionine sulfoximine (BSO) and decreased phosphorylation following pretreatment with the reducing agent dithiothreitol (DTT). Arsenic treatment of the cells also resulted in activation of the kinase domain of TAO2, as evidenced in in vitro kinase assay studies using ATF2 as an exogenous substrate. siRNA-mediated TAO2 knockdown resulted in inhibition of As2O3-induced p38 phosphorylation, suggesting that this kinase acts as an upstream effector of the arsenic-activated p38 MAPK pathway. Moreover, in studies to determine the functional relevance of TAO2 in the induction of As2O3-dependent antileukemic responses we found that siRNA-mediated TAO2 knockdown enhanced the suppressive effects of As2O3 on KT1-derived leukemic progenitor (CFU-L) growth in clonogenic assays in methylcellulose. Altogether, our data demonstrate that TAO2 is activated during arsenic treatment of leukemic cells lines and acts as an upstream activator of the p38 MAPK pathway. Such activation appears to occur in a negative feedback regulatory manner to compensate for the suppressive effects of As2O3 on leukemic cell growth. Importantly, these findings raise the possibility that targeting TAO2 may provide a novel approach to enhance the generation of the antileukemic properties of As2O3.

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PB1692 G-CSF ACTIVATING P38 MAPK PATHWAY ENHANCES THE ANTI-LEUKEMIC ACTIVITY OF ARSENIC TRIOXIDE IN VITRO THROUGH UP-REGULATING AQP9 EXPRESSION

HemaSphere ◽

10.1097/01.hs9.0000565284.14988.dc ◽

2019 ◽

Vol 3 (S1) ◽

pp. 779

Author(s):

A. Wang ◽

J. Wang ◽

X. Li ◽

H. Pu ◽

L. Xu ◽

...

Keyword(s):

Arsenic Trioxide ◽

P38 Mapk ◽

Mapk Pathway ◽

P38 Mapk Pathway

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Tougu Xiaotong capsules may inhibit p38 MAPK pathway-mediated inflammation: In vivo and in vitro verification

Journal of Ethnopharmacology ◽

10.1016/j.jep.2019.112390 ◽

2020 ◽

Vol 249 ◽

pp. 112390 ◽

Cited By ~ 1

Author(s):

Xihai Li ◽

Zhenli Zhang ◽

Wenna Liang ◽

Jianwei Zeng ◽

Xiang Shao ◽

...

Keyword(s):

P38 Mapk ◽

Mapk Pathway ◽

P38 Mapk Pathway

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Arsenic trioxide induces dose- and time-dependent apoptosis of endothelium and may exert an antileukemic effect via inhibition of angiogenesis

Blood ◽

10.1182/blood.v96.4.1525.h8001525_1525_1530 ◽

2000 ◽

Vol 96 (4) ◽

pp. 1525-1530 ◽

Cited By ~ 3

Author(s):

Gail J. Roboz ◽

Sergio Dias ◽

George Lam ◽

William J. Lane ◽

Steven L. Soignet ◽

...

Keyword(s):

Endothelial Cells ◽

Endothelial Cell ◽

Arsenic Trioxide ◽

Leukemic Cell ◽

Cell Types ◽

Time Dependent ◽

Leukemic Cells ◽

Sequence Of Events ◽

Antileukemic Effect

Arsenic trioxide (As2O3) has recently been used successfully in the treatment of acute promyelocytic leukemia and has been shown to induce partial differentiation and apoptosis of leukemic cells in vitro. However, the mechanism by which As2O3 exerts its antileukemic effect remains uncertain. Emerging data suggest that the endothelium and angiogenesis play a seminal role in the proliferation of liquid tumors, such as leukemia. We have shown that activated endothelial cells release cytokines that may stimulate leukemic cell growth. Leukemic cells, in turn, can release endothelial growth factors, such as vascular endothelial growth factor (VEGF). On the basis of these observations, we hypothesized that As2O3 may interrupt a reciprocal loop between leukemic cells and the endothelium by direct action on both cell types. We have shown that treatment of proliferating layers of human umbilical vein endothelial cells (HUVECs) with a variety of concentrations of As2O3results in a reproducible dose- and time-dependent sequence of events marked by change to an activated morphology, up-regulation of endothelial cell adhesion markers, and apoptosis. Also, treatment with As2O3 caused inhibition of VEGF production in the leukemic cell line HEL. Finally, incubation of HUVECs with As2O3 prevented capillary tubule and branch formation in an in vitro endothelial cell–differentiation assay. In conclusion, we believe that As2O3 interrupts a reciprocal stimulatory loop between leukemic cells and endothelial cells by causing apoptosis of both cell types and by inhibiting leukemic cell VEGF production.

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Acquired resistance to zoledronic acid and the parallel acquisition of an aggressive phenotype are mediated by p38-MAP kinase activation in prostate cancer cells

Cell Death and Disease ◽

10.1038/cddis.2013.165 ◽

2013 ◽

Vol 4 (5) ◽

pp. e641-e641 ◽

Cited By ~ 43

Author(s):

M R Milone ◽

B Pucci ◽

F Bruzzese ◽

C Carbone ◽

G Piro ◽

...

Keyword(s):

Prostate Cancer ◽

Zoledronic Acid ◽

P38 Mapk ◽

Mapk Pathway ◽

Critical Role ◽

Resistance Index ◽

P38 Map Kinase ◽

Cross Resistance ◽

Mesenchymal Transition ◽

P38 Mapk Pathway

Abstract The nitrogen-containing bisphosphonates (N-BP) zoledronic acid (ZOL) inhibits osteoclast-mediated bone resorption, and it is used to prevent skeletal complications from bone metastases. ZOL has also demonstrated anticancer activities in preclinical models and, recently, in cancer patients, highlighting the interest in determining eventual mechanisms of resistance against this agent. In our study, we selected and characterised a resistant subline of prostate cancer (PCa) cells to better understand the mechanisms, by which tumour cells can escape the antitumour effect of ZOL. DU145R80-resistant cells were selected in about 5 months using stepwise increasing concentrations of ZOL from DU145 parental cells. DU145R80 cells showed a resistance index value of 5.5 and cross-resistance to another N-BP, pamidronate, but not to the non-nitrogen containing BP clodronate. Notably, compared with DU145 parental cells, DU145R80 developed resistance to apoptosis and anoikis, as well as overexpressed the anti-apoptotic protein Bcl-2 and oncoprotein c-Myc. Moreover, DU145R80 cells underwent epithelial to mesenchymal transition (EMT) and showed increased expression of the metalloproteases MMP-2/9, as well as increased invading capability. Interestingly, compared with DU145, DU145R80 cells also increased the gene expression and protein secretion of VEGF and the cytokines Eotaxin-1 and IL-12. At the molecular level, DU145R80 cells showed strong activation of the p38-MAPK-dependent survival pathway compared with parental sensitive cells. Moreover, using the p38-inhibitor SB203580, we completely reversed the resistance to ZOL, as well as EMT marker expression and invasion. Furthermore, SB203580 treatment reduced the expression of VEGF, Eotaxin-1, IL-12, MMP-9, Bcl-2 and c-Myc. Thus, for the first time, we demonstrate that the p38-MAPK pathway can be activated under continuous extensive exposure to ZOL in PCa cells and that the p38-MAPK pathway has a critical role in the induction of resistance, as well as in the acquisition of a more aggressive and invasive phenotype.

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Sema4C participates in myogenic differentiation in vivo and in vitro through the p38 MAPK pathway

European Journal of Cell Biology ◽

10.1016/j.ejcb.2007.03.002 ◽

2007 ◽

Vol 86 (6) ◽

pp. 331-344 ◽

Cited By ~ 21

Author(s):

Haitao Wu ◽

Xuan Wang ◽

Shuhong Liu ◽

Yan Wu ◽

Tong Zhao ◽

...

Keyword(s):

P38 Mapk ◽

Mapk Pathway ◽

Myogenic Differentiation ◽

P38 Mapk Pathway

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Nephroprotective Effects of N-Acetylcysteine Amide against Contrast-Induced Nephropathy through Upregulating Thioredoxin-1, Inhibiting ASK1/p38MAPK Pathway, and Suppressing Oxidative Stress and Apoptosis in Rats

Oxidative Medicine and Cellular Longevity ◽

10.1155/2016/8715185 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11 ◽

Cited By ~ 14

Author(s):

Xuezhong Gong ◽

Yiru Duan ◽

Junli Zheng ◽

Yiquan Wang ◽

Guohua Wang ◽

...

Keyword(s):

Oxidative Stress ◽

P38 Mapk ◽

Mapk Pathway ◽

Contrast Induced Nephropathy ◽

Tubular Cells ◽

Renal Tubular Cells ◽

P38 Mapk Pathway ◽

Thioredoxin 1 ◽

Renal Tubular

Contrast-induced nephropathy (CIN) is a leading cause of hospital-acquired acute kidney injury (AKI) due to apoptosis induced in renal tubular cells. Our previous study demonstrated the novel N-acetylcysteine amide (NACA); the amide form of N-acetyl cysteine (NAC) prevented renal tubular cells from contrast-induced apoptosis through inhibiting p38 MAPK pathway in vitro. In the present study, we aimed to compare the efficacies of NACA and NAC in preventing CIN in a well-established rat model and investigate whether thioredoxin-1 (Trx1) and apoptosis signal-regulating kinase 1 (ASK1) act as the potential activator for p38 MAPK. NACA significantly attenuated elevations of serum creatinine, blood urea nitrogen, and biomarkers of AKI. At equimolar concentration, NACA was more effective than NAC in reducing histological changes of renal tubular injuries. NACA attenuated activation of p38 MAPK signal, reduced oxidative stress, and diminished apoptosis. Furthermore, we demonstrated that contrast exposure resulted in Trx1 downregulation and increased ASK1/p38 MAPK phosphorylation, which could be reversed by NACA and NAC. To our knowledge, this is the first report that Trx1 and ASK1 are involved in CIN. Our study highlights a renal protective role of NACA against CIN through modulating Trx1 and ASK1/p38 MAPK pathway to result in the inhibition of apoptosis among renal cells.

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P38 MAP kinase mediates transforming growth factor-β2 transcription in human keloid fibroblasts

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00472.2005 ◽

2006 ◽

Vol 290 (3) ◽

pp. R501-R508 ◽

Cited By ~ 26

Author(s):

Wei Xia ◽

Michael T. Longaker ◽

George P. Yang

Keyword(s):

P38 Mapk ◽

Transforming Growth Factor ◽

Mapk Pathway ◽

Human Fibroblasts ◽

Strong Association ◽

P38 Map Kinase ◽

Skin Tumor ◽

Protein Levels ◽

Serum Stimulation

Keloids are abnormal fibrous growths of the dermis that develop only in response to wounding and represent a form of benign skin tumor. Previous studies have shown increased protein levels of TGF-β in keloid tissue, suggesting a strong association with keloid formation leading us to examine mechanisms for why it is more highly expressed in keloids. Here, we use serum stimulation as an in vitro model to mimic a component of the wound microenvironment and examine differential gene expression in keloid human fibroblasts (KFs) vs. normal human fibroblasts (NFs). Transcription of TGF-β2 was rapid and peaked between 1 and 6 h after serum stimulation in KFs vs. NFs. We confirmed increased TGF-β activity in the conditioned medium from KFs, but not NFs. Inhibition of second messenger signaling pathways demonstrated that only the p38 MAPK inhibitor SB-203580 could block upregulation of TGF-β2 following serum stimulation in KFs. Immunoblotting demonstrated that p38 MAPK was phosphorylated within 15 min and was maintained at a high level in KFs but not in NFs. The transcription factors activating transcription factor-2 and Elk-1 are activated by p38 MAPK, and also showed rapid and prolonged phosphorylation kinetics in KFs but not in NFs. In conclusion, increased TGF-β2 transcription in response to serum stimulation in KFs appears to be mediated by the p38 MAPK pathway. This suggests the mechanism of keloid pathogenesis may be due in part to an inherent difference in how the fibroblasts respond to wounding.

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Glibenclamide–sulfonylurea receptor 1 antagonist alleviates LPS-induced BV2 cell activation through the p38/MAPK pathway

RSC Advances ◽

10.1039/c7ra03042h ◽

2017 ◽

Vol 7 (44) ◽

pp. 27206-27213 ◽

Cited By ~ 2

Author(s):

Zhiming Xu ◽

Yingliang Liu ◽

Dianxu Yang ◽

Fang Yuan ◽

Jun Ding ◽

...

Keyword(s):

P38 Mapk ◽

Microglial Activation ◽

Cell Activation ◽

Mapk Pathway ◽

Sulfonylurea Receptor ◽

P38 Mapk Pathway ◽

Sulfonylurea Receptor 1

We investigated the anti-neuroinflammatory activity and mechanism of glibenclamide, sulfonylurea receptor 1 (Sur1) antagonist, against LPS-induced microglial activationin vitro.

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