TP53 is required for BECN1- and ATG5-dependent cell death induced by sphingosine kinase 1 inhibition

Santiago Lima, Kazuaki Takabe, Jason Newton, Kumar Saurabh, Megan Marie Young, Andreia Machado Leopoldino, Nitai C. Hait, Jane L. Roberts, Hong-Gang Wang, Paul Dent, Sheldon Milstien, Laurence Booth, Sarah Spiegel

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The bioactive sphingolipid metabolite sphingosine-1-phosphate (S1P) and the enzyme that produces it, SPHK1 (sphingosine kinase 1), regulate many processes important for the etiology of cancer. It has been suggested that SPHK1 levels are regulated by the tumor suppressor protein TP53, a key regulator of cell cycle arrest, apoptosis, and macroautophagy/autophagy. However, little is still known of the relationship between TP53 and SPHK1 activity in the regulation of these processes. To explore this link, we examined the effects of inhibiting SPHK1 in wild-type and TP53 null cancer cell lines. SK1-I, an analog of sphingosine and isozyme-specific SPHK1 inhibitor, suppressed cancer cell growth and clonogenic survival in a TP53-dependent manner. It also more strongly enhanced intrinsic apoptosis in wild-type TP53 cells than in isogenic TP53 null cells. Intriguingly, SK1-I induced phosphorylation of TP53 on Ser15, which increases its transcriptional activity. Consequently, levels of TP53 downstream targets such as pro-apoptotic members of the BCL2 family, including BAX, BAK1, and BID were increased in wild-type but not in TP53 null cells. Inhibition of SPHK1 also increased the formation of autophagic and multivesicular bodies, and increased processing of LC3 and its localization within acidic compartments in a TP53-dependent manner. SK1-I also induced massive accumulation of vacuoles, enhanced autophagy, and increased cell death in an SPHK1-dependent manner that also required TP53 expression. Importantly, downregulation of the key regulators of autophagic flux, BECN1 and ATG5, dramatically decreased the cytotoxicity of SK1-I only in cells with TP53 expression. Hence, our results reveal that TP53 plays an important role in vacuole-associated cell death induced by SPHK1 inhibition in cancer cells.

Original languageEnglish (US)
Pages (from-to)942-957
Number of pages16
JournalAutophagy
Volume14
Issue number6
DOIs
StatePublished - Jun 3 2018

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Cell Death
Null Lymphocytes
Autophagy
Vacuoles
Neoplasms
Apoptosis
Multivesicular Bodies
Tumor Suppressor Proteins
Sphingolipids
Sphingosine
Inhibition (Psychology)
sphingosine kinase
Cell Cycle Checkpoints
Isoenzymes
Down-Regulation
Phosphorylation
Cell Line
Enzymes
Growth

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology

Cite this

Lima, Santiago ; Takabe, Kazuaki ; Newton, Jason ; Saurabh, Kumar ; Young, Megan Marie ; Leopoldino, Andreia Machado ; Hait, Nitai C. ; Roberts, Jane L. ; Wang, Hong-Gang ; Dent, Paul ; Milstien, Sheldon ; Booth, Laurence ; Spiegel, Sarah. / TP53 is required for BECN1- and ATG5-dependent cell death induced by sphingosine kinase 1 inhibition. In: Autophagy. 2018 ; Vol. 14, No. 6. pp. 942-957.
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abstract = "The bioactive sphingolipid metabolite sphingosine-1-phosphate (S1P) and the enzyme that produces it, SPHK1 (sphingosine kinase 1), regulate many processes important for the etiology of cancer. It has been suggested that SPHK1 levels are regulated by the tumor suppressor protein TP53, a key regulator of cell cycle arrest, apoptosis, and macroautophagy/autophagy. However, little is still known of the relationship between TP53 and SPHK1 activity in the regulation of these processes. To explore this link, we examined the effects of inhibiting SPHK1 in wild-type and TP53 null cancer cell lines. SK1-I, an analog of sphingosine and isozyme-specific SPHK1 inhibitor, suppressed cancer cell growth and clonogenic survival in a TP53-dependent manner. It also more strongly enhanced intrinsic apoptosis in wild-type TP53 cells than in isogenic TP53 null cells. Intriguingly, SK1-I induced phosphorylation of TP53 on Ser15, which increases its transcriptional activity. Consequently, levels of TP53 downstream targets such as pro-apoptotic members of the BCL2 family, including BAX, BAK1, and BID were increased in wild-type but not in TP53 null cells. Inhibition of SPHK1 also increased the formation of autophagic and multivesicular bodies, and increased processing of LC3 and its localization within acidic compartments in a TP53-dependent manner. SK1-I also induced massive accumulation of vacuoles, enhanced autophagy, and increased cell death in an SPHK1-dependent manner that also required TP53 expression. Importantly, downregulation of the key regulators of autophagic flux, BECN1 and ATG5, dramatically decreased the cytotoxicity of SK1-I only in cells with TP53 expression. Hence, our results reveal that TP53 plays an important role in vacuole-associated cell death induced by SPHK1 inhibition in cancer cells.",
author = "Santiago Lima and Kazuaki Takabe and Jason Newton and Kumar Saurabh and Young, {Megan Marie} and Leopoldino, {Andreia Machado} and Hait, {Nitai C.} and Roberts, {Jane L.} and Hong-Gang Wang and Paul Dent and Sheldon Milstien and Laurence Booth and Sarah Spiegel",
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Lima, S, Takabe, K, Newton, J, Saurabh, K, Young, MM, Leopoldino, AM, Hait, NC, Roberts, JL, Wang, H-G, Dent, P, Milstien, S, Booth, L & Spiegel, S 2018, 'TP53 is required for BECN1- and ATG5-dependent cell death induced by sphingosine kinase 1 inhibition', Autophagy, vol. 14, no. 6, pp. 942-957. https://doi.org/10.1080/15548627.2018.1429875

TP53 is required for BECN1- and ATG5-dependent cell death induced by sphingosine kinase 1 inhibition. / Lima, Santiago; Takabe, Kazuaki; Newton, Jason; Saurabh, Kumar; Young, Megan Marie; Leopoldino, Andreia Machado; Hait, Nitai C.; Roberts, Jane L.; Wang, Hong-Gang; Dent, Paul; Milstien, Sheldon; Booth, Laurence; Spiegel, Sarah.

In: Autophagy, Vol. 14, No. 6, 03.06.2018, p. 942-957.

Research output: Contribution to journalArticle

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T1 - TP53 is required for BECN1- and ATG5-dependent cell death induced by sphingosine kinase 1 inhibition

AU - Lima, Santiago

AU - Takabe, Kazuaki

AU - Newton, Jason

AU - Saurabh, Kumar

AU - Young, Megan Marie

AU - Leopoldino, Andreia Machado

AU - Hait, Nitai C.

AU - Roberts, Jane L.

AU - Wang, Hong-Gang

AU - Dent, Paul

AU - Milstien, Sheldon

AU - Booth, Laurence

AU - Spiegel, Sarah

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