TY - JOUR
T1 - Functional cooperativity of p97 and histone deacetylase 6 in mediating DNA repair in mantle cell lymphoma cells
AU - Vekaria, Pratikkumar H.
AU - Kumar, Amar
AU - Subramaniam, Dharmalingam
AU - Dunavin, Neil
AU - Vallurupalli, Anusha
AU - Schoenen, Frank
AU - Ganguly, Siddhartha
AU - Anant, Shrikant
AU - McGuirk, Joseph P.
AU - Jensen, Roy A.
AU - Rao, Rekha
N1 - Publisher Copyright:
© 2019, Springer Nature Limited.
PY - 2019/7/1
Y1 - 2019/7/1
N2 - p97 is an ATPase that works in concert with histone deacetylase 6 (HDAC6), to facilitate the degradation of misfolded proteins by autophagosomes. p97 has also been implicated in DNA repair and maintaining genomic stability. In this study, we determined the effect of combined inhibition of p97 and HDAC6 activities in mantle cell lymphoma (MCL) cells. We report that treatment with p97 inhibitors induces dose-dependent apoptosis in MCL cells. The p97 inhibitor CB-5083 induces ER stress markers GRP78 and CHOP and results in the accumulation of polyubiquitylated proteins. Co-treatment with CB-5083 and the HDAC6 inhibitor ACY-1215 result in marked downregulation of CDK4, Cyclin D1, and BRCA1 levels without inhibiting autophagic flux. Consequently, treatment with CB-5083 accentuates DNA damage in response to treatment with ACY-1215 resulting in enhanced accumulation of H2AX-γ and synergistic apoptosis. Furthermore, ATM loss severely impairs phosphorylation of 53BP1 following co-treatment with CB-5083 and ACY-1215 in response to gamma irradiation. Finally, co-treatment CB-5083 and ACY-1215 results in reduced tumor volumes and improves survival in Z138C and Jeko-1 xenografts in NSG mice. These observations suggest that combined inhibition of p97 and HDAC6 abrogates resolution of proteotoxic stress and impairs DNA repair mechanisms in MCL cells.
AB - p97 is an ATPase that works in concert with histone deacetylase 6 (HDAC6), to facilitate the degradation of misfolded proteins by autophagosomes. p97 has also been implicated in DNA repair and maintaining genomic stability. In this study, we determined the effect of combined inhibition of p97 and HDAC6 activities in mantle cell lymphoma (MCL) cells. We report that treatment with p97 inhibitors induces dose-dependent apoptosis in MCL cells. The p97 inhibitor CB-5083 induces ER stress markers GRP78 and CHOP and results in the accumulation of polyubiquitylated proteins. Co-treatment with CB-5083 and the HDAC6 inhibitor ACY-1215 result in marked downregulation of CDK4, Cyclin D1, and BRCA1 levels without inhibiting autophagic flux. Consequently, treatment with CB-5083 accentuates DNA damage in response to treatment with ACY-1215 resulting in enhanced accumulation of H2AX-γ and synergistic apoptosis. Furthermore, ATM loss severely impairs phosphorylation of 53BP1 following co-treatment with CB-5083 and ACY-1215 in response to gamma irradiation. Finally, co-treatment CB-5083 and ACY-1215 results in reduced tumor volumes and improves survival in Z138C and Jeko-1 xenografts in NSG mice. These observations suggest that combined inhibition of p97 and HDAC6 abrogates resolution of proteotoxic stress and impairs DNA repair mechanisms in MCL cells.
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U2 - 10.1038/s41375-018-0355-y
DO - 10.1038/s41375-018-0355-y
M3 - Article
C2 - 30664664
AN - SCOPUS:85060348573
SN - 0887-6924
VL - 33
SP - 1675
EP - 1686
JO - Leukemia
JF - Leukemia
IS - 7
ER -