Large-scale CRISPR screening efforts have shown that cancer cells are not equally dependent on all genes; instead, they rely on specific molecular pathways for survival. However, translating these dependency maps into clinically meaningful targets has been challenging, because the molecular mechanisms underlying such dependencies remain poorly understood. Breast cancer is particularly heterogeneous, with distinct subtypes exhibiting diverse genetic, metabolic, and signaling features. Without a clear framework linking gene dependencies to tumor molecular characteristics, many potential vulnerabilities remain unexplored. Based on these challenges, there is a pressing need to systematically investigate how molecular alterations shape cancer cell dependencies and to identify therapeutically relevant targets.
Researchers from Fudan University Shanghai Cancer Center report a comprehensive analysis of breast cancer vulnerabilities in a study published (DOI: 10.20892/j.issn.2095-3941.2025.0290) in Cancer Biology & Medicine. By integrating CRISPR gene-dependency screens with multi-omics data from 47 breast cancer cell lines, the team developed a dependency-marker association (DMA) framework to uncover why cancer cells rely on specific genes. Their findings reveal distinct dependency patterns linked to oncogenic activation, metabolic rewiring, and subtype-specific molecular features, offering new directions for precision breast cancer therapy.
The study introduces a pipeline that quantitatively links gene essentiality to mutations, copy-number alterations, DNA methylation, RNA expression, protein abundance, and metabolite levels. This approach allows cancer dependencies to be interpreted through two biologically meaningful mechanisms.
First, the analysis identifies gene addiction, where cancer cells become highly dependent on genes activated by oncogenic or metabolic reprogramming. A striking example is the lactate transporter encoded by SLC16A3, which shows increased dependency in highly glycolytic breast cancer cells. These cells rely on efficient lactate export to maintain metabolic balance, making SLC16A3 a promising therapeutic target.
Second, the study systematically maps synthetic lethal interactionsarising from loss-of-function alterations. These include classic tumor-suppressor-linked vulnerabilities, collateral lethality caused by co-deleted passenger genes, and metabolic synthetic lethality involving paralogous enzymes or alternative metabolic pathways. The researchers further stratified breast cancer cell lines into two dependency-based clusters. One cluster displayed strong mitochondrial and metabolic dependencies, while the other relied more on DNA replication, cell-cycle regulation, and signaling pathways—reflecting fundamental biological differences between luminal/HER2-positive and basal-like breast cancer subtypes.
“The key advance of this work is linking statistical dependency signals to biologically interpretable mechanisms,” the authors note. Rather than treating gene dependencies as isolated observations, the study demonstrates how oncogenic activation, metabolic rewiring, and pathway redundancy collectively shape cancer vulnerabilities. By distinguishing true therapeutic dependencies from incidental correlations, the framework helps prioritize targets that are more likely to translate into effective treatments. The authors emphasize that this integrative strategy could improve the rational design of targeted therapies and reduce trial-and-error in drug development.
The findings provide a practical roadmap for precision oncology. By identifying subtype-specific dependencies and mechanistically grounded synthetic lethal interactions, the study points to new opportunities for combination therapies that exploit cancer-specific weaknesses. Metabolic targets such as the SLC16A3 pathway or nucleotide-synthesis genes may be particularly effective when paired with genomic biomarkers. Beyond breast cancer, the DMA framework can be applied to other tumor types to systematically uncover actionable vulnerabilities. As multi-omics data become increasingly available in clinical settings, this approach may help guide personalized treatment decisions and accelerate the translation of dependency maps into real-world cancer therapies.
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References
DOI
10.20892/j.issn.2095-3941.2025.0290
Original Source URL
https://doi.org/10.20892/j.issn.2095-3941.2025.0290
Funding Information
This work was supported by grants from the National Key Research and Development Project of China (Grant No. 2020YFA0112304) and the National Natural Science Foundation of China (Grant Nos. 91959207 and 82202883).
About Cancer Biology & Medicine
Cancer Biology & Medicine (CBM) is a peer-reviewed open-access journal sponsored by China Anti-cancer Association (CACA) and Tianjin Medical University Cancer Institute & Hospital. The journal monthly provides innovative and significant information on biological basis of cancer, cancer microenvironment, translational cancer research, and all aspects of clinical cancer research. The journal also publishes significant perspectives on indigenous cancer types in China. The journal is indexed in SCOPUS, MEDLINE and SCI (IF 8.4, 5-year IF 6.7), with all full texts freely visible to clinicians and researchers all over the world (http://www.ncbi.nlm.nih.gov/pmc/journals/2000/).