Browsing by Author "Utley, Adam"

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    Pro-survival signaling regulates lipophagy essential for multiple myeloma resistance to stress-induced death
    (Elsevier, 2024) Peng, Peng; Chavel, Colin; Liu, Wensheng; Carlson, Louise M.; Cao, Sha; Utley, Adam; Olejniczak, Scott H.; Lee, Kelvin P.; Biostatistics and Health Data Science, Richard M. Fairbanks School of Public Health
    Pro-survival metabolic adaptations to stress in tumorigenesis remain less well defined. We find that multiple myeloma (MM) is unexpectedly dependent on beta-oxidation of long-chain fatty acids (FAs) for survival under both basal and stress conditions. However, under stress conditions, a second pro-survival signal is required to sustain FA oxidation (FAO). We previously found that CD28 is expressed on MM cells and transduces a significant pro-survival/chemotherapy resistance signal. We now find that CD28 signaling regulates autophagy/lipophagy that involves activation of the Ca2+→AMPK→ULK1 axis and regulates the translation of ATG5 through HuR, resulting in sustained lipophagy, increased FAO, and enhanced MM survival. Conversely, blocking autophagy/lipophagy sensitizes MM to chemotherapy in vivo. Our findings link a pro-survival signal to FA availability needed to sustain the FAO required for cancer cell survival under stress conditions and identify lipophagy as a therapeutic target to overcome treatment resistance in MM.
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    The fatty acid elongase ELOVL6 regulates bortezomib resistance in multiple myeloma
    (American Society of Hematology, 2021) Lipchick, Brittany C.; Utley, Adam; Han, Zhannan; Moparthy, Sudha; Yun, Dong Hyun; Bianchi-Smiraglia, Anna; Wolff, David W.; Fink, Emily; Liu, Liang; Furdui, Cristina M.; Lee, Jingyun; Lee, Kelvin P.; Nikiforov, Mikhail A.; Medicine, School of Medicine
    Resistance to the proteasome inhibitor bortezomib (BTZ) represents a major obstacle in the treatment of multiple myeloma (MM). The contribution of lipid metabolism in the resistance of MM cells to BTZ is mostly unknown. Here we report that levels of fatty acid elongase 6 (ELOVL6) were lower in MM cells from BTZ-nonresponsive vs BTZ-responsive patients and in cultured MM cells selected for BTZ resistance compared with parental counterparts. Accordingly, depletion of ELOVL6 in parental MM cells suppressed BTZ-induced endoplasmic reticulum (ER) stress and cytotoxicity, whereas restoration of ELOVL6 levels in BTZ-resistant MM cells sensitized them to BTZ in tissue culture settings and, as xenografts, in a plasmacytoma mouse model. Furthermore, for the first time, we identified changes in the BTZ-induced lipidome between parental and BTZ-resistant MM cell lines underlying a functional difference in their response to BTZ. We demonstrated that restoration of ELOVL6 levels in BTZ-resistant MM cells resensitized them to BTZ largely via upregulation of ELOVL6-dependent ceramide species, which was a prerequisite for BTZ-induced ER stress and cell death in these cells. Our data characterize ELOVL6 as a major clinically relevant regulator of MM cell resistance to BTZ, which can emerge from the impaired ability of these cells to alter ceramide composition in response to BTZ.