Dataset Information

P53 C-terminal acetylation modulates apoptotic program

ABSTRACT: Advanced colorectal cancer (CRC) is an unresolved clinical problem. Epigenetic drugs belonging to the group of histone deacetylase inhibitors (HDACi) may combat CRC in rationally designed treatment schedules. Unfortunately, there is sparse evidence on molecular mechanisms and markers that determine cellular sensitivity to HDACi. Irinotecan is widely used to treat CRC and causes replication stress (RS) and DNA damage as topoisomerase-I inhibitor. We applied irinotecan and the class I HDACi entinostat (MS-275) to isogenic p53-positive and -negative CRC cells. Combinations of irinotecan and MS-275 evoke mitochondrial damage, caspase-mediated apoptosis, and RS-associated DNA damage synergistically and p53-dependently. Targeted mass spectrometry and immunoblot show that irinotecan induces phosphorylation, acetylation, and accumulation of p53 and its target genes. Addition of MS-275 augments the irinotecan-induced acetylation of C-terminal lysine residues of p53 but decreases its phosphorylation and p53 target gene induction. Furthermore, MS-275 increases the amount of acetylated p53 at mitochondria and dysregulates the expression of pro- and anti-apoptotic BCL2 proteins in irinotecan-treated cells. Regarding DNA repair, we see that MS-275 represses the homologous recombination (HR) filament protein RAD51, which limits DNA damage and pro-apoptotic effects of irinotecan. These data suggest that key class I HDAC-dependent functions of p53 in cells with RS are linked to mitochondrial damage and a breakdown of HR. Most importantly, combinations of irinotecan plus MS-275 also kill short-term primary CRC cell cultures and organoids from CRC patients but spare organoids of adjacent matched normal tissue. Thus, irinotecan/HDACi treatment is a promising new approach for the therapy of p53-proficient tumors with clinically tractable inhibitors.

INSTRUMENT(S): LTQ Orbitrap Velos

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Colon Epithelial Cell, Colon

DISEASE(S): Colon Cancer

SUBMITTER: Sergio Lilla

LAB HEAD: Sara Rossana Zanivan

PROVIDER: PXD019999 | Pride | 2022-02-15

REPOSITORIES: Pride

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			Action	DRS
	040414_SEL_OT_CHM_R15_280314_R1_A_001.raw	Raw
	040414_SEL_OT_CHM_R15_280314_R1_B_001.raw	Raw
	040414_SEL_OT_CHM_R15_280314_R1_C_001.raw	Raw
	040414_SEL_OT_CHM_R15_280314_R1_D_001.raw	Raw
	040414_SEL_OT_CHM_R15_280314_R2_A_002.raw	Raw

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Publications

Mechanistic insights into p53-regulated cytotoxicity of combined entinostat and irinotecan against colorectal cancer cells.

Marx Christian C Sonnemann Jürgen J Beyer Mandy M Maddocks Oliver D K ODK Lilla Sergio S Hauzenberger Irene I Piée-Staffa Andrea A Siniuk Kanstantsin K Nunna Suneetha S Marx-Blümel Lisa L Westermann Martin M Wagner Tobias T Meyer Felix B FB Thierbach René R Mullins Christina S CS Kdimati Said S Linnebacher Michael M Neri Francesco F Heinzel Thorsten T Wang Zhao-Qi ZQ Krämer Oliver H OH

Molecular oncology 20210729 12

Late-stage colorectal cancer (CRC) is still a clinically challenging problem. The activity of the tumor suppressor p53 is regulated via post-translational modifications (PTMs). While the relevance of p53 C-terminal acetylation for transcriptional regulation is well defined, it is unknown whether this PTM controls mitochondrially mediated apoptosis directly. We used wild-type p53 or p53-negative human CRC cells, cells with acetylation-defective p53, transformation assays, CRC organoids, and xenog ...[more]

PMID: 34258881

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