CYP19A1 Regulates Chemoresistance in Colorectal Cancer Through Modulation of Estrogen Biosynthesis and Mitochondrial Function
CYP19A1 Regulates Chemoresistance in Colorectal Cancer through Modulation of Estrogen Biosynthesis and Mitochondrial Function
Background
Colorectal cancer (CRC) is one of the leading causes of cancer-related mortality worldwide. Despite significant advances in early detection and treatment strategies, chemoresistance remains a major obstacle to effective CRC treatment, contributing to poor patient prognosis and high mortality rates. The molecular mechanisms underlying chemoresistance are complex and multifaceted, with emerging evidence suggesting that alterations in mitochondrial function and hormone signaling pathways play crucial roles. CYP19A1 (cytochrome P450 family 19 subfamily A member 1), also known as aromatase, is a key enzyme in estrogen biosynthesis. Although the role of CYP19A1 in hormone-dependent cancers has been extensively studied, its function in CRC remains largely unexplored. Given the importance of estrogen signaling in various cellular processes, including mitochondrial function and energy metabolism, researchers hypothesized that CYP19A1 might play a significant role in regulating mitochondrial activity and chemoresistance in CRC cells.
Source of the Paper
This paper was co-authored by Yang Wang, Qiang Ji, Ning Cao, Guijie Ge, Xiaomin Li, Xiangdong Liu, and Yanqi Mi, affiliated with the Department of General Surgery at Longhua Hospital, Shanghai University of Traditional Chinese Medicine; the Department of Pharmacy at Sunshine Union Hospital, Weifang; the Emergency General Surgery Department at Weifang People’s Hospital, Shandong Second Medical University; the Department of Anesthesiology II Endoscopy Center at Weifang People’s Hospital; the Medical Center of Gastrointestinal Surgery at Weifang People’s Hospital; and the Department of Pharmacy at Weifang People’s Hospital. The paper was published in 2024 in the journal Cancer & Metabolism under the title “CYP19A1 regulates chemoresistance in colorectal cancer through modulation of estrogen biosynthesis and mitochondrial function.”
Research Process and Results
1. Expression and Localization of CYP19A1 in CRC Cells
The study first analyzed RNA sequencing data from The Cancer Genome Atlas (TCGA) database and found that CYP19A1 mRNA expression was significantly higher in CRC tissues compared to normal colon tissues. Subsequent real-time quantitative PCR and Western blot analyses confirmed that CYP19A1 mRNA and protein levels were significantly upregulated in multiple CRC cell lines. To further understand the function of CYP19A1, researchers performed immunofluorescence staining and found that CYP19A1 was primarily localized to mitochondria and partially to the endoplasmic reticulum in CRC cells. This finding suggests that CYP19A1 may play an important role in regulating mitochondrial function in CRC cells.
2. Impact of CYP19A1 Knockout on Mitochondrial Respiration
To investigate the effect of CYP19A1 on mitochondrial respiration, researchers generated CYP19A1 knockout SW480 and HT29 CRC cell lines using CRISPR-Cas9 technology. Through Seahorse mitochondrial stress tests, they found that CYP19A1 knockout significantly reduced basal respiration, ATP-linked respiration, and maximal respiration capacity in CRC cells. Additionally, CYP19A1 knockout led to a significant decrease in mitochondrial complex I activity, while the activities of complexes III, IV, and V remained unaffected. These results indicate that CYP19A1 plays a critical role in maintaining complex I activity and optimal respiratory function in CRC cells.
3. CYP19A1 Regulates Mitochondrial Function through Its Enzymatic Activity and Estrogen Biosynthesis
CYP19A1 plays a key role in estrogen biosynthesis by catalyzing the conversion of androgens to estrogens. To determine whether the enzymatic activity of CYP19A1 is required for its regulation of mitochondrial function, researchers used lentiviral vectors to express wild-type CYP19A1 and its catalytically inactive mutants (D309N and Y361F) in CYP19A1 knockout cells. The results showed that only the expression of wild-type CYP19A1 could restore mitochondrial respiration in CYP19A1 knockout cells, while the catalytically inactive mutants had no such effect. Furthermore, supplementation with estradiol (E2) also completely restored mitochondrial respiration in CYP19A1 knockout cells, indicating that CYP19A1 regulates mitochondrial function through its enzymatic activity and estrogen biosynthesis.
4. Effects of Pharmacological Inhibition of CYP19A1 or Mitochondrial Complex I on CRC Cells
To further validate the role of CYP19A1 in mitochondrial function, researchers treated CRC cells with the CYP19A1-specific inhibitor anastrozole and the mitochondrial complex I inhibitor IACS-010759. The results showed that both anastrozole and IACS-010759 significantly inhibited mitochondrial respiration in CRC cells, reduced cellular ATP content, and increased reactive oxygen species (ROS) levels. These findings further support the critical role of CYP19A1 and mitochondrial complex I in regulating mitochondrial respiration and cellular energy homeostasis in CRC cells.
5. Targeting CYP19A1 Reverses Chemoresistance in CRC
Researchers established chemoresistant CRC cell lines by continuous exposure to 5-fluorouracil (5-FU), irinotecan, and oxaliplatin. The results showed that CYP19A1 knockout significantly suppressed mitochondrial respiration and complex I activity in chemoresistant cells, reversing their chemoresistance. Additionally, overexpression of CYP19A1 or supplementation with estradiol increased the tolerance of parental cells to chemotherapeutic drugs, while exogenous expression of wild-type CYP19A1 or estradiol supplementation reversed the chemosensitization effect caused by CYP19A1 knockout. These results suggest that CYP19A1 regulates chemoresistance in CRC cells through its enzymatic activity and estrogen biosynthesis.
6. Clinical Data Analysis
By analyzing clinical data from the TCGA database, researchers found that high CYP19A1 expression was significantly associated with poor overall survival in CRC patients receiving chemotherapy. Multivariate Cox regression analysis showed that high CYP19A1 expression was significantly associated with increased risk of death in patients treated with 5-FU and oxaliplatin, while sex and the interaction between CYP19A1 and sex had no significant impact. These results further support the clinical significance of CYP19A1 in CRC chemoresistance.
Conclusions and Significance
This study reveals a novel role for CYP19A1 in regulating chemoresistance in CRC through modulation of mitochondrial function and complex I activity, and identifies the CYP19A1/estrogen/complex I axis as a potential therapeutic target for overcoming chemoresistance. The findings demonstrate that targeting CYP19A1 or complex I can effectively reverse chemoresistance in CRC cells, highlighting its clinical application value. Furthermore, analysis of clinical data from the TCGA database confirms the clinical relevance of CYP19A1 in chemotherapy response. These findings provide new insights into the molecular mechanisms underlying chemoresistance in CRC and offer a theoretical foundation for developing new treatment strategies.
Research Highlights
- Novel Discovery: For the first time, the study reveals the critical role of CYP19A1 in regulating chemoresistance in CRC through modulation of mitochondrial function and complex I activity.
- Innovative Methods: The use of CRISPR-Cas9 technology to generate CYP19A1 knockout cell lines, combined with Seahorse mitochondrial stress tests and pharmacological inhibition experiments, systematically investigates the function of CYP19A1.
- Clinical Significance: Analysis of the TCGA database shows that high CYP19A1 expression is significantly associated with poor prognosis in chemotherapy-treated patients, providing evidence for CYP19A1 as a predictive biomarker for chemotherapy response.
- Therapeutic Potential: The results demonstrate that targeting CYP19A1 or complex I can effectively reverse chemoresistance in CRC cells, offering promising clinical applications.
Additional Valuable Information
The study also found that CYP19A1 is localized not only to mitochondria but also partially to the endoplasmic reticulum in CRC cells, suggesting that it may have diverse functions in different cellular compartments. Additionally, the study explores the complex interplay between CYP19A1 and estrogen signaling pathways in chemoresistance, providing new directions for future research.