- What was tested: 5 mM ammonium acetate or ammonium chloride, products of glutamine breakdown (glutaminolysis), added to Sp2/0-Ag14 mouse hybridoma cells starved of glutamine for 3 hours [1].
- Main result: viability, measured 24 hours after the cells were returned to complete medium, rose from 30% without ammonium to 54% with ammonium chloride and 72% with ammonium acetate. Glutamine-fed controls were above 90% [1].
- Mechanism clue: ammonium did not reduce caspase-3 activation or cytochrome c release, but it reduced apoptotic nuclear condensation and fragmentation [1].
- Limits: one mouse cell line in culture. The rescue was partial, and the mechanism was not identified [1].
Why this matters
As cancer cells reprogram their metabolism, many become dependent on glutamine, a dependence called glutamine addiction that underlies several new therapeutic strategies [1]. For background, see the earlier explainer on glutamine addiction.
Breaking down glutamine produces two end products: α-ketoglutarate and ammonium ions [1]. Ammonium is generally considered harmful to cells, yet some studies have shown that it can prevent apoptosis. That raised a question: when glutamine runs out, could changes in ammonium metabolism help decide whether a cell dies [1]? The same cell line was used in the group’s earlier work on MCL-1 and obatoclax [2].
The study
Sp2/0-Ag14 (Sp2/0) mouse hybridoma cells undergo apoptosis through the intrinsic pathway within minutes of glutamine deprivation [1]. The researchers placed the cells in glutamine-free medium for 3 hours, with 5 mM ammonium acetate (AA) or ammonium chloride (AC) added to some cultures. Controls received PBS, sodium acetate or sodium chloride, and glutamine-fed cultures served as a reference [1].
The team measured viability by trypan blue exclusion (24 hours after the cells were returned to complete medium), colony formation, and Annexin V and propidium iodide flow cytometry. They also measured caspase-3 activity and processing, cleavage of Lamin A/C and PARP, DNA fragmentation, cytochrome c release, and nuclear shape with Hoechst staining. Statistics were two-tailed Student’s t tests, with p < 0.05 as the threshold [1].
What the researchers found
| Question | Result |
|---|---|
| Do ammonium salts improve viability? | Yes. Viability was 30% with PBS, 54% with AC and 72% with AA. Sodium salts gave results similar to PBS, methylamine chloride did not help, and glutamine-fed controls were above 90% [1]. |
| Do other assays agree? | Yes. Colony formation and Annexin V and propidium iodide staining also showed significantly more surviving cells with AA or AC [1]. |
| Is new glutamine synthesis needed? | No. The glutamine synthetase inhibitor MSO did not block the benefit [1]. |
| Does α-ketoglutarate add to it? | Not additively. Dimethyl-αKG alone raised viability (43% versus 20%), but gave no extra protection when combined with ammonium [1]. |
| Is core apoptosis blocked? | No. Caspase-3 activity and processing, Lamin A/C and PARP cleavage, DNA fragmentation and cytochrome c release were not reduced [1]. |
| What did ammonium change? | It significantly reduced the share of starved cells with apoptotic nuclear condensation and fragmentation [1]. |
Ammonium can supply amine groups for glutamine synthesis through glutamate dehydrogenase and glutamine synthetase. MSO (10 mM) sensitized the human Ramos B-cell line to starvation but did not lower Sp2/0 viability further, which the authors link to low glutamine synthetase activity in mouse hybridomas, and it did not block the ammonium effect. Dimethyl-αKG was limited to 2 mM because higher doses were toxic to Sp2/0 cells, which may explain the lack of an additive effect [1].
What this does not show
- A partial rescue. Ammonium was not sufficient to stop the death program completely. The authors say other factors are required, possibly additional glutamine-derived metabolites [1].
- One mouse cell line in culture. Whether similar effects occur in human cells or in tumors was not tested; the human Ramos line was used only as an inhibitor control [1].
- An open mechanism. The authors discuss possibilities drawn from other studies, such as effects on phospholipase A2, autophagy, protein glycosylation and potassium transport. These were not tested here [1].
- One dose. All experiments used 5 mM ammonium salts. The study does not address ammonium levels in tumors [1].
What happens next
The authors conclude that ammonium, a major product of glutaminolysis, should be considered a potential target of anti-cancer strategies, and that survival-signaling pathways modulated by ammonium ions should be examined [1]. The group’s earlier study found that MCL-1 falls in glutamine-starved Sp2/0 cells and that obatoclax sensitizes them to apoptosis [2].
- Paper
- Abusneina A, Gauthier ER. Cell & Bioscience 6:23, 2016. doi:10.1186/s13578-016-0092-8
- PubMed
- PMID 27087916
- Full text
- Free on PubMed Central; the full text was used for this summary
- Disclosure
- The author of this post is the first author of the paper.
- Funding
- Listed in the paper.
This post summarizes a published study for general information.
References
- A. Abusneina and E. R. Gauthier, “Ammonium ions improve the survival of glutamine-starved hybridoma cells,” Cell Biosci., vol. 6, art. 23, Apr. 2016. doi: 10.1186/s13578-016-0092-8. PMID: 27087916. Full text: PMC4832542.
- C. C. Harnett, A. Abusneina, J. Clément, and E. R. Gauthier, “Inhibition of MCL-1 by obatoclax sensitizes Sp2/0-Ag14 hybridoma cells to glutamine deprivation-induced apoptosis,” Cell Biochem. Funct., vol. 33, no. 5, pp. 334–340, Jul. 2015. doi: 10.1002/cbf.3121. PMID: 26178811.
Related articles
Feature · Oct 19, 2026MCL-1 and Apoptosis: What Obatoclax Teaches Us About Cancer Cell Death
Explainer · Oct 19, 2026Glutamine Addiction: Why Some Cancer Cells Depend on a Nonessential Amino Acid
Feature · Oct 19, 2026Why a Glutaminolysis Signature Falls With PTEN Loss: Passenger Co-Deletion, Not Metabolic RegulationResearch focus: Molecular Oncology and Cancer Metabolism
Department of Molecular Diagnostics, Faculty of Biomedical Sciences, University of Benghazi, Libya
Comments
No account needed. Comments are reviewed before they appear. Please be respectful and on topic.