Zinc-finger protein ZNF207 protects the glutamine transporter ASCT2 from ubiquitin-proteasome degradation in hepatocellular carcinoma, according to a study published in Cellular Oncology. The finding positions the ZNF207-ASCT2 axis as a potential therapeutic vulnerability in a malignancy notorious for its dependence on glutamine metabolism.

Hepatocellular carcinoma is a lethal cancer characterized by glutamine addiction, yet the role of ZNF207 in this metabolic context had remained unclear. The research team set out to clarify how the zinc-finger regulator contributes to HCC progression. Their experiments combined growth curve analysis, colony formation assays and a subcutaneous xenograft model to track proliferation, while apoptosis was measured through Annexin V/PI flow cytometry and caspase-3/7 activity assays. Protein expression and pathway activation were examined by immunoblotting, and the relationship between ZNF207 and ASCT2 was probed with genetic rescue experiments, cycloheximide chase assays, ubiquitination assays and co-immunoprecipitation.

ZNF207 knockdown significantly suppressed HCC cell proliferation and induced apoptosis, with more pronounced growth inhibition observed in glutamine-sensitive HCC cells. ZNF207 knockdown significantly suppressed HCC cell proliferation and induced apoptosis, with the growth inhibition proving more pronounced in glutamine-sensitive HCC cells. In line with this phenotype, ZNF207 positively regulated the protein abundance of the glutamine transporter ASCT2 and was associated with activation of the AKT/mTORC1 signaling pathway.

A crucial detail emerged when the researchers examined ASCT2 mRNA. ZNF207 knockdown did not alter ASCT2 transcript levels, yet it markedly promoted ubiquitin-proteasome-mediated degradation of the transporter protein. This distinction matters because it indicates that ZNF207 regulates ASCT2 at the post-translational level rather than at the transcript level.

The mechanistic thread led to SPOP, an E3 ubiquitin ligase adaptor. When ZNF207 was disrupted, the association between ASCT2 and SPOP increased, accompanied by heightened ASCT2 ubiquitination and proteasomal degradation. ZNF207 disruption enhanced the association between ASCT2 and the E3 ubiquitin ligase adaptor SPOP, accompanied by increased ASCT2 ubiquitination and proteasomal degradation.

Genetic rescue experiments were used to investigate the functional relationship between ZNF207 and ASCT2.

In HCC specimens, high ZNF207 expression was positively correlated with ASCT2 mRNA levels, and elevated ZNF207 was associated with aggressive clinicopathological features and poor prognosis. In HCC specimens, high ZNF207 expression was positively correlated with ASCT2 mRNA levels, and was associated with aggressive clinicopathological features and poor prognosis.

Therapeutically, the authors conclude that ZNF207 acts as a positive regulator of ASCT2 protein stability through modulation of SPOP-associated ubiquitination, highlighting the ZNF207-ASCT2 axis as a potential therapeutic vulnerability in HCC. The study relied on cell lines, a subcutaneous xenograft model and clinical specimen correlations, and further work will be needed to determine whether the ZNF207-ASCT2 axis can be targeted therapeutically in patients with hepatocellular carcinoma.

As the article is being shared early as a peer-reviewed accepted manuscript, the final Version of Record may include further edits.

Subject of Research: The role of ZNF207 in stabilizing the glutamine transporter ASCT2 and sustaining AKT/mTORC1 signaling in hepatocellular carcinoma.

Article Title: ZNF207 safeguards ASCT2 from ubiquitin-proteasome degradation to sustain AKT/mTORC1 signaling in hepatocellular carcinoma

Article References: Chen, Z., Chen, J., Li, T., Jiang, L., Wu, H., Zhang, R., Zhang, Y., Sulaiman, M., Cheng, Y., Yuan, S., Zhang, Z., & Yang, M. (2026). ZNF207 safeguards ASCT2 from ubiquitin-proteasome degradation to sustain AKT/mTORC1 signaling in hepatocellular carcinoma. Cellular Oncology. https://doi.org/10.1007/s13402-026-01294-3

Image Credits: AI Generated

DOI: 10.1007/s13402-026-01294-3

Keywords: ZNF207, ASCT2, hepatocellular carcinoma, glutamine addiction, ubiquitin-proteasome degradation, SPOP, AKT/mTORC1 signaling, protein stability, liver cancer, glutamine transporter, E3 ubiquitin ligase, poor prognosis