Class IIa HDAC inhibition enhances ER stress-mediated cell death in multiple myeloma

S Kikuchi, R Suzuki, H Ohguchi, Y Yoshida, D Lu, F Cottini, J Jakubikova, G Bianchi, T Harada, G Gorgun, Y-T Tai, P G Richardson, T Hideshima, K C Anderson
Leukemia: Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K 2015, 29 (9): 1918-27
Histone deacetylase (HDAC) inhibitors have been extensively investigated as therapeutic agents in cancer. However, the biological role of class IIa HDACs (HDAC4, 5, 7 and 9) in cancer cells, including multiple myeloma (MM), remains unclear. Recent studies show HDAC4 interacts with activating transcription factor 4 (ATF4) and inhibits activation of endoplasmic reticulum (ER) stress-associated proapoptotic transcription factor C/EBP homologous protein (CHOP). In this study, we hypothesized that HDAC4 knockdown and/or inhibition could enhance apoptosis in MM cells under ER stress condition by upregulating ATF4, followed by CHOP. HDAC4 knockdown showed modest cell growth inhibition; however, it markedly enhanced cytotoxicity induced by either tunicamycin or carfilzomib (CFZ), associated with upregulating ATF4 and CHOP. For pharmacological inhibition of HDAC4, we employed a novel and selective class IIa HDAC inhibitor TMP269, alone and in combination with CFZ. As with HDAC4 knockdown, TMP269 significantly enhanced cytotoxicity induced by CFZ in MM cell lines, upregulating ATF4 and CHOP and inducing apoptosis. Conversely, enhanced cytotoxicity was abrogated by ATF4 knockdown, confirming that ATF4 has a pivotal role mediating cytotoxicity in this setting. These results provide the rationale for novel treatment strategies combining class IIa HDAC inhibitors with ER stressors, including proteasome inhibitors, to improve patient outcome in MM.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"