Oncotarget

Research Papers:

Inhibition of glucosylceramide synthase eliminates the oncogenic function of p53 R273H mutant in the epithelial-mesenchymal transition and induced pluripotency of colon cancer cells

Salman B. Hosain, Sachin K. Khiste, Mohammad B. Uddin, Vindya Vorubindi, Catherine Ingram, Sifang Zhang, Ronald A. Hill, Xin Gu and Yong-Yu Liu _

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Oncotarget. 2016; 7:60575-60592. https://doi.org/10.18632/oncotarget.11169

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Abstract

Salman B. Hosain1, Sachin K. Khiste1, Mohammad B. Uddin1, Vindya Vorubindi1, Catherine Ingram1, Sifang Zhang2, Ronald A. Hill1, Xin Gu3, Yong-Yu Liu1

1Department of Basic Pharmaceutical Sciences, University of Louisiana at Monroe, Monroe, LA 71201, USA

2Department of Integrated Chinese and Western Medicine, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, China

3Department of Pathology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA

Correspondence to:

Yong-Yu Liu, email: yliu@ulm.edu

Keywords: tumor suppressor p53, epithelial-mesenchymal transition, cancer stem cells, glucosylceramide synthase, missense mutation

Received: December 10, 2015    Accepted: July 26, 2016    Published: August 10, 2016

ABSTRACT

Missense mutation of tumor suppressor p53, which exhibits oncogenic gain-of-function (GOF), not only promotes tumor progression, but also diminishes therapeutic efficacies of cancer treatments. However, it remains unclear how a p53 missense mutant contributes to induced pluripotency of cancer stem cells (CSCs) in tumors exposed to chemotherapeutic agents. More importantly, it may be possible to abrogate the GOF by restoring wild-type p53 activity, thereby overcoming the deleterious effects resulting from heterotetramer formation, which often compromises the efficacies of current approaches being used to reactivate p53 function. Herewith, we report that p53 R273H missense mutant urges cancer cells to spawn CSCs. SW48/TP53 cells, which heterozygously carry the p53 R273H hot-spot mutant (R273H/+, introduced by a CRISPR/Casp9 system), were subchronically exposed to doxorubicin in cell culture and in tumor-bearing mice. We found that p53-R273H (TP53-Dox) cells were drug-resistant and exhibited epithelial-mesenchymal transition (EMT) and increased numbers of CSCs (CD44v6+/CD133+), which resulted in enhanced wound healing and tumor formation. Inhibition of glucosylceramide synthase with d-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) sensitized p53-R273H cancer cells and tumor xenografts to doxorubicin treatments. Intriguingly, PDMP treatments restored wild-type p53 expression in heterozygous R273H mutant cells and in tumors, decreasing CSCs and sensitizing cells and tumors to treatments. This study demonstrated that p53-R273H promotes EMT and induced pluripotency of CSCs in cancer cells exposed to doxorubicin, mainly through Zeb1 and β-catenin transcription factors. Our results further indicate that restoration of p53 through inhibition of ceramide glycosylation might be an effective treatment approach for targeting cancers heterozygously harboring TP53 missense mutations.


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