The histone methyltransferase DOT1L is required for proper DNA damage response, DNA repair, and modulates chemotherapy responsiveness

TY - JOUR

T1 - The histone methyltransferase DOT1L is required for proper DNA damage response, DNA repair, and modulates chemotherapy responsiveness

AU - Kari, Vijayalakshmi

AU - Raul, Sanjay Kumar

AU - Henck, Jana Maria

AU - Kitz, Julia

AU - Kramer, Frank

AU - Kosinsky, Robyn Laura

AU - Übelmesser, Nadine

AU - Mansour, Wael Yassin

AU - Eggert, Jessica

AU - Spitzner, Melanie

AU - Najafova, Zeynab

AU - Bastians, Holger

AU - Grade, Marian

AU - Gaedcke, Jochen

AU - Wegwitz, Florian

AU - Johnsen, Steven A

PY - 2019/1/7

Y1 - 2019/1/7

N2 - BACKGROUND: Disruptor of telomeric silencing 1-like (DOT1L) is a non-SET domain containing methyltransferase known to catalyze mono-, di-, and tri-methylation of histone 3 on lysine 79 (H3K79me). DOT1L-mediated H3K79me has been implicated in chromatin-associated functions including gene transcription, heterochromatin formation, and DNA repair. Recent studies have uncovered a role for DOT1L in the initiation and progression of leukemia and other solid tumors. The development and availability of small molecule inhibitors of DOT1L may provide new and unique therapeutic options for certain types or subgroups of cancer.METHODS: In this study, we examined the role of DOT1L in DNA double-strand break (DSB) response and repair by depleting DOT1L using siRNA or inhibiting its methyltransferase activity using small molecule inhibitors in colorectal cancer cells. Cells were treated with different agents to induce DNA damage in DOT1L-depleted or -inhibited cells and analyzed for DNA repair efficiency and survival. Further, rectal cancer patient samples were analyzed for H3K79me3 levels in order to determine whether it may serve as a potential marker for personalized therapy.RESULTS: Our results indicate that DOT1L is required for a proper DNA damage response following DNA double-strand breaks by regulating the phosphorylation of the variant histone H2AX (γH2AX) and repair via homologous recombination (HR). Importantly, we show that small molecule inhibitors of DOT1L combined with chemotherapeutic agents that are used to treat colorectal cancers show additive effects. Furthermore, examination of H3K79me3 levels in rectal cancer patients demonstrates that lower levels correlate with a poorer prognosis.CONCLUSIONS: In this study, we conclude that DOT1L plays an important role in an early DNA damage response and repair of DNA double-strand breaks via the HR pathway. Moreover, DOT1L inhibition leads to increased sensitivity to chemotherapeutic agents and PARP inhibition, which further highlights its potential clinical utility. Our results further suggest that H3K79me3 can be useful as a predictive and or prognostic marker for rectal cancer patients.

AB - BACKGROUND: Disruptor of telomeric silencing 1-like (DOT1L) is a non-SET domain containing methyltransferase known to catalyze mono-, di-, and tri-methylation of histone 3 on lysine 79 (H3K79me). DOT1L-mediated H3K79me has been implicated in chromatin-associated functions including gene transcription, heterochromatin formation, and DNA repair. Recent studies have uncovered a role for DOT1L in the initiation and progression of leukemia and other solid tumors. The development and availability of small molecule inhibitors of DOT1L may provide new and unique therapeutic options for certain types or subgroups of cancer.METHODS: In this study, we examined the role of DOT1L in DNA double-strand break (DSB) response and repair by depleting DOT1L using siRNA or inhibiting its methyltransferase activity using small molecule inhibitors in colorectal cancer cells. Cells were treated with different agents to induce DNA damage in DOT1L-depleted or -inhibited cells and analyzed for DNA repair efficiency and survival. Further, rectal cancer patient samples were analyzed for H3K79me3 levels in order to determine whether it may serve as a potential marker for personalized therapy.RESULTS: Our results indicate that DOT1L is required for a proper DNA damage response following DNA double-strand breaks by regulating the phosphorylation of the variant histone H2AX (γH2AX) and repair via homologous recombination (HR). Importantly, we show that small molecule inhibitors of DOT1L combined with chemotherapeutic agents that are used to treat colorectal cancers show additive effects. Furthermore, examination of H3K79me3 levels in rectal cancer patients demonstrates that lower levels correlate with a poorer prognosis.CONCLUSIONS: In this study, we conclude that DOT1L plays an important role in an early DNA damage response and repair of DNA double-strand breaks via the HR pathway. Moreover, DOT1L inhibition leads to increased sensitivity to chemotherapeutic agents and PARP inhibition, which further highlights its potential clinical utility. Our results further suggest that H3K79me3 can be useful as a predictive and or prognostic marker for rectal cancer patients.

KW - Cell Line, Tumor

KW - DNA Breaks, Double-Stranded/drug effects

KW - Drug Resistance, Neoplasm

KW - Epigenesis, Genetic

KW - HCT116 Cells

KW - Histone-Lysine N-Methyltransferase

KW - Histones/metabolism

KW - Humans

KW - Methylation

KW - Methyltransferases/antagonists & inhibitors

KW - Phosphorylation

KW - Prognosis

KW - RNA, Small Interfering/pharmacology

KW - Recombinational DNA Repair

KW - Rectal Neoplasms/metabolism

KW - Small Molecule Libraries/pharmacology

U2 - 10.1186/s13148-018-0601-1

DO - 10.1186/s13148-018-0601-1

M3 - SCORING: Journal article

C2 - 30616689

VL - 11

SP - 4

JO - CLIN EPIGENETICS

JF - CLIN EPIGENETICS

SN - 1868-7075

IS - 1

ER -