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Updated: Jan 15, 2026
Expression of Transgenes in Native Bladder Urothelium Using Adenovirus-Mediated Transduction
Published on: October 6, 2022
STAG2 regulates polycomb and differentiation in urothelial precursors and bladder cancer
Youngrok Park1,2, Wanying Xu3,4, Tianyi Yang3,4
1Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University School of Medicine, Washington, District of Columbia, United States of America.
Abstract:
The STAG2 tumor suppressor gene is commonly inactivated by mutations in a wide range of common cancer types. STAG2 encodes a component of the cohesin complex, which controls sister chromatid cohesion and 3D genome organization. In bladder cancer, STAG2 mutations are most common in the earliest low-grade lesions, suggesting that mutational inactivation of STAG2 may be an initiating event. To provide insight into the mechanisms of STAG2 tumor suppression in bladder cancer, siRNA and shRNA were used to knock down STAG2 in several different human non-neoplastic bladder cancer precursor cell lines. Gene editing was used to generate cultured human cancer cell lines that differ only in the presence or absence of bladder-cancer derived STAG2 mutations. These systems were interrogated using RNA-seq, Western blot, and qRT-PCR before and after induced differentiation. We find that inactivation of STAG2 in bladder cancer cells and in bladder epithelial precursor cells resulted in concomitant inactivation of the H3K27me3 Polycomb chromatin mark. Inactivation of STAG2 also attenuated induced differentiation of bladder epithelial precursor cells. STAG2 and other components of cohesin were upregulated during this differentiation process. This study provides new insights into the role of STAG2 in the pathogenesis of bladder cancer, demonstrating roles for STAG2 in the regulation of Polycomb-mediated epigenetic regulation and in the differentiation of bladder epithelial precursor cells.
Insights
Mutations in the STAG2 gene, crucial for cell division, are linked to bladder cancer initiation. Inactivating STAG2 disrupts epigenetic regulation and hinders cell differentiation, offering new therapeutic targets.
Area of Science:
- Genetics
- Epigenetics
- Cancer Biology
Background:
- The STAG2 tumor suppressor gene is frequently mutated in various cancers, including bladder cancer.
- STAG2 is a key component of the cohesin complex, essential for sister chromatid cohesion and genome organization.
- STAG2 mutations in bladder cancer often occur early, suggesting a role in tumor initiation.
Purpose of the Study:
- To investigate the mechanisms of STAG2 tumor suppression in bladder cancer.
- To understand STAG2's role in epigenetic regulation and cell differentiation in bladder epithelial cells.
Main Methods:
- Utilized siRNA and shRNA to knockdown STAG2 in bladder cancer precursor cell lines.
- Employed gene editing to create cell lines with and without STAG2 mutations.
- Analyzed gene expression and protein levels using RNA-seq, Western blot, and qRT-PCR before and after induced differentiation.
Main Results:
- STAG2 inactivation led to the loss of the H3K27me3 Polycomb chromatin mark in bladder cancer and precursor cells.
- Impaired induced differentiation of bladder epithelial precursor cells upon STAG2 inactivation.
- Observed upregulation of STAG2 and cohesin components during normal bladder epithelial cell differentiation.
Conclusions:
- STAG2 plays a significant role in regulating Polycomb-mediated epigenetic processes.
- STAG2 is critical for the differentiation of bladder epithelial precursor cells.
- Findings provide novel insights into STAG2's function in bladder cancer pathogenesis and suggest potential therapeutic avenues.
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