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AMBRA1 attenuates the proliferation of uveal melanoma cells
Binbin Zhao1, Yun Yang2, Biyun Cun3
1Department of Ophthalmology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200127, China.
Abstract:
Uveal melanoma (UVM) is the most common primary intraocular malignancy in adults with high metastasis rates. D-type cyclins (CCNDs) are central regulators of the cell division cycle and are among the most frequently deregulated therapeutic targets in human cancer. Recently, the E3 ligase adaptor, autophagy and beclin 1 regulator 1 (AMBRA1), was reported to regulate the stability of CCNDs, including CCND1, but its role in UVM has not been demonstrated. AMBRA1 is lowly expressed in UVM cells, and the ablation of AMBRA1 promotes the proliferation of 92.1 and OMM1 cells, whereas ectopically expressing AMBRA1 attenuates the proliferation of UVM cells. Further studies found that AMBRA1 promotes the ubiquitination and degradation of CCND1, and AMBRA1 regulates the proliferation of UVM cells in a CCND1-dependent manner. Thus, this study suggests that AMBRA1 serves as an important tumor suppressor by limiting UVM cell growth.
Insights
Autophagy and beclin 1 regulator 1 (AMBRA1) acts as a tumor suppressor in uveal melanoma (UVM). Low AMBRA1 expression promotes UVM cell proliferation by stabilizing CCND1, while its restoration inhibits growth.
Area of Science:
- Oncology
- Molecular Biology
- Cell Biology
Background:
- Uveal melanoma (UVM) is the most common primary intraocular cancer in adults, characterized by high metastasis rates.
- D-type cyclins (CCNDs) are critical cell cycle regulators and frequent therapeutic targets in cancers.
- The E3 ligase adaptor AMBRA1 regulates CCND stability, but its role in UVM is unexplored.
Purpose of the Study:
- To investigate the role of AMBRA1 in the proliferation of uveal melanoma cells.
- To determine the relationship between AMBRA1, CCND1, and UVM cell growth.
Main Methods:
- Assessing AMBRA1 expression levels in UVM cells.
- Manipulating AMBRA1 expression (ablation and ectopic expression) in UVM cell lines (92.1 and OMM1).
- Investigating the ubiquitination and degradation of CCND1 mediated by AMBRA1.
Main Results:
- AMBRA1 is expressed at low levels in UVM cells.
- AMBRA1 ablation enhances UVM cell proliferation, whereas AMBRA1 overexpression inhibits it.
- AMBRA1 promotes CCND1 ubiquitination and degradation, thereby regulating UVM cell proliferation in a CCND1-dependent manner.
Conclusions:
- AMBRA1 functions as a tumor suppressor in uveal melanoma.
- AMBRA1 limits UVM cell growth by targeting CCND1 for degradation.
