CCNE1 Enhances TNBC Stemness by Inhibiting FZR1

In a groundbreaking study poised to shift paradigms in cancer biology, researchers have unveiled a novel molecular mechanism by which the protein CCNE1 enhances the aggressiveness and stemness of triple-negative breast cancer (TNBC) cells. Published in the prestigious journal Cell Death Discovery, this work dissects the intricate interplay between CCNE1 and ANLN, revealing how CCNE1 stabilizes ANLN by mitigating FZR1-mediated ubiquitination—a process usually responsible for protein degradation. This discovery not only illuminates a critical pathway driving TNBC progression but also opens promising avenues for therapeutic intervention in one of the most challenging breast cancer subtypes.

Triple-negative breast cancer lacks expression of estrogen receptor, progesterone receptor, and HER2, characteristics which render it particularly refractory to conventional hormone therapies and targeted treatments. This has urged the scientific community to delve deeper into its molecular underpinnings. The study by Dai, Li, Guo, and their colleagues offers compelling evidence that CCNE1, a cell cycle regulator previously associated with tumor proliferation, plays a pivotal role in maintaining the stemness and malignancy of TNBC cells by directly influencing the stability of ANLN, anillin actin-binding protein renowned for its role in cytokinesis and cellular architecture.

Central to the researchers’ findings is the elucidation of how CCNE1 counteracts the ubiquitination activity mediated by FZR1, an E3 ubiquitin ligase-associated co-activator known to target specific proteins for proteasomal degradation. Normally, FZR1 triggers ubiquitin chains that mark ANLN for destruction, thereby controlling its cellular levels. However, the stabilization of ANLN by CCNE1 effectively prevents this degradation, resulting in sustained ANLN activity. Elevated ANLN levels, in turn, promote the maintenance of cancer stem cell-like properties—cells capable of self-renewal, differentiation, and potent tumor initiation—hallmarks closely tied to cancer progression and metastasis.

The intricate regulation of ANLN’s stability unveils a hitherto unexplored axis in TNBC biology. Notably, ANLN has been documented in previous studies to facilitate cytoskeletal remodeling and to contribute to cell division fidelity. Its aberrant elevation in cancer cells correlates with enhanced motility and invasiveness, traits that underpin metastatic spread. By demonstrating that CCNE1 safeguards ANLN from ubiquitination and degradation, this research specifies a molecular safeguard system leveraged by malignancies to uphold a stem cell–like state and fortify tumor aggressiveness.

Delving deeper into mechanistic details, the team utilized loss- and gain-of-function experiments to tease apart the functional consequences of manipulating CCNE1 and ANLN levels. Silencing CCNE1 led to a marked reduction in ANLN protein abundance and a concurrent decrease in cancer stemness markers. Conversely, overexpression of CCNE1 robustly increased ANLN stability and bolstered the phenotypic traits associated with tumor initiation and progression in TNBC models. These observations firmly position CCNE1 as an upstream regulator critical for sustaining ANLN-mediated oncogenic pathways.

A salient aspect of the study is the identification of FZR1’s role as a key modulator within this axis. FZR1 typically promotes ubiquitination targeting proteins for degradation during cell cycle exit, thus acting as a tumor suppressive barrier by limiting oncogenic protein accumulation. The discovery that CCNE1 can effectively “neutralize” FZR1’s function with respect to ANLN underpins a strategic molecular subversion favoring tumor growth. This signifies that tumors with elevated CCNE1 may evade a crucial proteostasis checkpoint, facilitating continuous ANLN activity and unrestrained proliferation.

The implications for clinical strategies are profound. TNBC patients currently face a dire need for novel therapeutic targets due to their tumors’ aggressive nature and resistance to existing treatments. Targeting the CCNE1-ANLN-FZR1 axis presents a specific vulnerability that might be exploited pharmacologically to disrupt cancer stem cell maintenance, inhibit tumor growth, and prevent metastasis. Small molecule inhibitors, proteolysis targeting chimeras (PROTACs), or biologics designed to restore FZR1’s ubiquitin ligase activity or block CCNE1’s interaction with ANLN could be transformative.

Moreover, the researchers highlight the potential of using CCNE1 and ANLN expression levels as prognostic biomarkers. Their correlation with poorer patient outcomes suggests that quantifying these proteins could provide predictive insight into tumor aggressiveness and guide personalized treatment strategies. Incorporating such biomarkers into clinical workflows could enhance diagnostic accuracy and optimize therapy selection, a critical step toward precision oncology.

At the molecular level, the study underscores the complexity of protein stability regulation in cancer cells, intertwining ubiquitination pathways with cell cycle control proteins like CCNE1. The crosstalk between ubiquitin-proteasome system components and cell cycle regulators emerges as a nuanced regulatory network essential for cancer stem cell biology. This not only deepens our understanding of tumor heterogeneity but also accentuates the need for integrative approaches combining molecular biology, biochemistry, and systems biology to unravel cancer’s resilience mechanisms.

The authors employed cutting-edge experimental techniques ranging from immunoprecipitation assays, ubiquitination analyses, and protein stability assays to in vitro and in vivo tumorigenicity models, thereby providing robust validation of their mechanistic claims. These methodologies confirm a direct biochemical interaction involving CCNE1 and ANLN and establish causality in TNBC phenotypes. Their use of CRISPR-Cas9 technology to selectively manipulate gene expression further reinforces the precision of their molecular insights.

Additionally, the study’s exploration of cancer stem cell traits—such as self-renewal capacity, resistance to apoptosis, and enhanced tumorigenic potential—provides a conceptual framework for understanding how alterations in protein degradation pathways directly contribute to cancer persistence and relapse. By maintaining ANLN levels, CCNE1 empowers cancer cells to sustain these aggressive properties, suggesting that disrupting this balance could improve therapeutic efficacy.

This research also provokes broader questions regarding the ubiquitination landscape in cancer. Given the multiplicity of E3 ligases and their substrates, and the fine-tuned targeting facilitated by co-activators like FZR1, unraveling the specificity and redundancy within these systems is poised to become a vibrant domain of investigation. Insights into how oncogenic proteins evade degradation through hijacking regulatory circuits are instrumental in identifying novel nodes for drug targeting, particularly in malignancies characterized by proteostasis disruptions.

In conclusion, the identification of the CCNE1-mediated stabilization of ANLN via interference with FZR1-driven ubiquitination marks a significant advance in breast cancer research, with pronounced relevance to triple-negative breast cancer. The findings from Dai and colleagues not only elucidate previously unrecognized molecular interactions but also chart a promising course toward novel therapeutics addressing the urgent challenge of TNBC. This study exemplifies the power of dissecting molecular cancer pathways to yield actionable targets and fosters optimism for improved patient outcomes in this devastating disease.

As cancer research continues to evolve with high-resolution molecular tools and integrative platforms, studies like this underscore the necessity of detailed mechanistic insights to dismantle cancer’s defenses. The unraveling of CCNE1’s role in sustaining oncogenic proteins via ubiquitination pathways represents a beacon for future innovations—from bench to bedside—in the relentless battle against triple-negative breast cancer.

Subject of Research: The molecular mechanism by which CCNE1 stabilizes ANLN by counteracting FZR1-mediated ubiquitination to promote triple-negative breast cancer cell stemness and progression.

Article Title: CCNE1 stabilizes ANLN by counteracting FZR1-mediated ubiquitination to promote triple-negative breast cancer cell stemness and progression.

Article References:
Dai, S., Li, L., Guo, G. et al. CCNE1 stabilizes ANLN by counteracting FZR1-mediated the ubiquitination modification to promotes triple negative breast cancer cell stemness and progression. Cell Death Discov. 11, 228 (2025). https://doi.org/10.1038/s41420-025-02518-5

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41420-025-02518-5

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