Targeted inhibition of tumor-specific glutaminase diminishes cell-autonomous tumorigenesis
Yan Xiang, … , Dean W. Felsher, Chi V. Dang
Yan Xiang, … , Dean W. Felsher, Chi V. Dang
Published April 27, 2015
Citation Information: J Clin Invest. 2015;125(6):2293-2306. https://doi.org/10.1172/JCI75836.
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Research Article Oncology

Targeted inhibition of tumor-specific glutaminase diminishes cell-autonomous tumorigenesis

Abstract

Glutaminase (GLS), which converts glutamine to glutamate, plays a key role in cancer cell metabolism, growth, and proliferation. GLS is being explored as a cancer therapeutic target, but whether GLS inhibitors affect cancer cell–autonomous growth or the host microenvironment or have off-target effects is unknown. Here, we report that loss of one copy of Gls blunted tumor progression in an immune-competent MYC-mediated mouse model of hepatocellular carcinoma. Compared with results in untreated animals with MYC-induced hepatocellular carcinoma, administration of the GLS-specific inhibitor bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl)ethyl sulfide (BPTES) prolonged survival without any apparent toxicities. BPTES also inhibited growth of a MYC-dependent human B cell lymphoma cell line (P493) by blocking DNA replication, leading to cell death and fragmentation. In mice harboring P493 tumor xenografts, BPTES treatment inhibited tumor cell growth; however, P493 xenografts expressing a BPTES-resistant GLS mutant (GLS-K325A) or overexpressing GLS were not affected by BPTES treatment. Moreover, a customized Vivo-Morpholino that targets human GLS mRNA markedly inhibited P493 xenograft growth without affecting mouse Gls expression. Conversely, a Vivo-Morpholino directed at mouse Gls had no antitumor activity in vivo. Collectively, our studies demonstrate that GLS is required for tumorigenesis and support small molecule and genetic inhibition of GLS as potential approaches for targeting the tumor cell–autonomous dependence on GLS for cancer therapy.

Authors

Yan Xiang, Zachary E. Stine, Jinsong Xia, Yunqi Lu, Roddy S. O’Connor, Brian J. Altman, Annie L. Hsieh, Arvin M. Gouw, Ajit G. Thomas, Ping Gao, Linchong Sun, Libing Song, Benedict Yan, Barbara S. Slusher, Jingli Zhuo, London L. Ooi, Caroline G.L. Lee, Anthony Mancuso, Andrew S. McCallion, Anne Le, Michael C. Milone, Stephen Rayport, Dean W. Felsher, Chi V. Dang

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Figure 4

Effects of GLS inhibition by BPTES on cell cycle, BrdU incorporation, cyclins, γH2AX, cleaved PARP levels, and morphology of P493 cells.

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Effects of GLS inhibition by BPTES on cell cycle, BrdU incorporation, cy...
(A) Arrested P493 cells were washed to remove Tet to induce MYC expression and were untreated, DMSO treated, or BPTES treated. Cells at the indicated time points after wash were stained with propidium iodide to measure total DNA content by flow cytometry. (B) DMSO-treated control cells were pulse labeled with BrdU and then counterstained with 7-AAD for flow cytometry of samples obtained at the indicate times after MYC induction. Zero-hour control cells were untreated. (C) BPTES-treated cells were studied under conditions outlined in B. (D–G) Protein lysates from control or BPTES-treated unsynchronized cells at the indicated times after treatment were obtained and then immunoblotted for the following: (D) cyclin E1 (CycE1); (E) cyclin B1 (CycB1); (F) γH2AX; and (G) cleaved PARP. D and E share a tubulin blot from sequential staining of the same blot. (H) Photomicrographs of DMSO- and BPTES-treated P493 cells at low and high power. Scale bars: 50 μm (left panels); 20 μm (right panels).