Detection of DHRS2-associated E3 Ubiquitin Ligases in Breast Cancer Cell Lines

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Objective: The ubiquitin system plays a central role in regulating intracellular protein homeostasis and cellular signaling. E3 ubiquitin ligases, in particular, are key modulators of protein degradation and have been implicated in cancer progression, including breast cancer. DHRS2, a gene known to suppress MDM2 activity through its ubiquitin-binding domain, has recently emerged as a potential regulator in tumor biology. This study investigated how DHRS2 expression influences selected E3 ubiquitin ligase genes in breast epithelial cells.Materials and Methods: MCF-7 and MCF-10A cell lines were used. DHRS2 was either overexpressed using a vector-based system, or silenced via siRNA. After transfection, quantitative reverse transcription polymerase chain reaction (qRT–PCR) was performed to evaluate changes in the expression levels of BRCA1, BARD1, and STUB1.Results: In MCF-7 cells, DHRS2 overexpression induced a fourfold increase in BRCA1 expression, whereas STUB1 and BARD1 were downregulated (0.56-fold). In MCF-10A cells with naturally low DHRS2, STUB1 expression increased 1.5-fold after DHRS2 knockdown, and BARD1 expression correlated positively with DHRS2 levels.Conclusion: This study highlights a potential regulatory link between DHRS2 and key E3 ubiquitin ligases-BRCA1, BARD1, and STUB1. Differential patterns across cell types indicate DHRS2 as a context-dependent modulator of ubiquitin-mediated pathways, supporting its relevance in biomarker discovery and therapeutic targeting in breast cancer.