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Restraining SRD5A1 combined with BRD4 inhibitor delaying prostate cancer progression by decreasing AR expression
Yifan Liu1, Duocheng Qian2, Yifan Ding1
1Department of Urology, Tongji Hospital, School of Medicine, Tongji University, Shanghai, 200065, China.
Abstract:
With increasing life expectancy, prostate cancer (PCa) has exhibited rising incidence and mortality rates. Although therapies such as androgen deprivation therapy (ADT) effectively extend patient survival, the development of drug resistance remains a major obstacle. Previous studies identified a key enzyme in the androgen metabolic pathway as essential to PCa progression, regulated by the epigenetic reader BRD4. Bioinformatic analysis revealed that SRD5A1, a critical enzyme in androgen metabolism, is downregulated by the BRD4 inhibitor JQ1. This finding was validated using I-BET151, another BRD4 inhibitor, which also suppressed SRD5A1 expression in PCa cell lines. Furthermore, treatment with dutasteride (Duta), an SRD5A family inhibitor, significantly reduced both cell proliferation and invasion. Mechanistic investigations demonstrated that SRD5A1 promotes androgen receptor (AR) activity by elevating intracellular dihydrotestosterone (DHT) levels, thereby enhancing AR expression and facilitating tumorigenesis. Notably, both BRD4 and SRD5A1 were shown to modulate AR expression in PCa cells. Co-administration of BRD4 and SRD5A1 inhibitors yielded a more pronounced suppression of AR expression. These findings highlight the pivotal role of SRD5A1 in PCa progression and suggest that combinatorial inhibition of BRD4 and SRD5A1 may provide a more effective strategy for attenuating AR expression and halting disease development.
Insights
Targeting SRD5A1 and BRD4 offers a new strategy for prostate cancer (PCa). Inhibiting these targets reduces androgen receptor (AR) expression, potentially halting PCa progression and overcoming drug resistance.
Area of Science:
- Oncology
- Molecular Biology
- Epigenetics
Background:
- Prostate cancer (PCa) incidence and mortality are rising with increased life expectancy.
- Androgen deprivation therapy (ADT) is effective but faces drug resistance challenges.
- The epigenetic reader BRD4 regulates key enzymes in androgen metabolism crucial for PCa progression.
Purpose of the Study:
- To investigate the role of SRD5A1 in PCa progression.
- To evaluate the efficacy of inhibiting SRD5A1 and BRD4 in PCa.
- To explore combination therapy for enhanced AR suppression in PCa.
Main Methods:
- Bioinformatic analysis to identify SRD5A1 regulation by BRD4.
- In vitro studies using PCa cell lines with BRD4 inhibitors (JQ1, I-BET151) and SRD5A1 inhibitor (dutasteride).
- Assessment of SRD5A1's mechanism in promoting AR activity and dihydrotestosterone (DHT) levels.
Main Results:
- BRD4 inhibitors (JQ1, I-BET151) downregulated SRD5A1 expression in PCa cells.
- SRD5A1 inhibition via dutasteride reduced PCa cell proliferation and invasion.
- SRD5A1 was found to enhance AR activity by increasing intracellular DHT, thereby promoting AR expression and tumorigenesis.
- Both BRD4 and SRD5A1 modulate AR expression, with combined inhibition showing greater suppression.
Conclusions:
- SRD5A1 plays a critical role in prostate cancer progression by modulating AR activity.
- Combined inhibition of BRD4 and SRD5A1 presents a promising therapeutic strategy to suppress AR expression and halt PCa development.
- This combinatorial approach may overcome resistance associated with current therapies like ADT.
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