AATF is Overexpressed in Human Bladder Cancer and Regulates Chemo-Sensitivity Through Survivin
Shutao Tan1, Lin Fu2, Qianze Dong2
1Department of Urology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
Objective:
Dysregulation of apoptosis antagonizing transcription factor (AATF) has been reported to be closely associated with human cancers. However, its involvement in human bladder cancer (BC) remains unexplored. This study aimed to investigate the clinical significance and biological roles of AATF in human bladder cancers.
Methods:
AATF protein expression was examined in 107 cases of bladder cancer tissues using immunohistochemistry. AATF plasmid transfection and small interfering RNA (siRNA) knockdown were performed in T24 and 5637 cell lines. CCK-8, colony formation, annexin V/PI, JC-1 staining, and Western blotting were carried out to investigate the biological roles and underlying mechanisms of AATF in bladder cancer cells.
Results:
Our results showed that AATF expression was upregulated in human bladder cancer specimens and correlated with T stage. Analysis of the Oncomine database showed elevation of AATF mRNA in BC tissues. The Cancer Genome Atlas (TCGA) data suggested that high AATF expression correlated with poor patient survival. Western blotting showed that AATF protein expression was higher in BC cell lines compared to normal bladder transitional epithelial cell line SV-HUC-1. CCK-8 and colony assays showed that ectopic AATF expression upregulated cell growth rate and colony numbers. CCK-8, annexin V/propidium iodide (PI), JC-1 assays and Western blotting showed that AATF overexpression decreased cisplatin sensitivity, downregulated cisplatin-induced apoptosis and upregulated mitochondrial membrane potential, with decreased cytochrome c and cleaved-PARP expression. AATF siRNA knockdown showed the opposite effects. Mechanistically, AATF overexpression upregulated cyclin E and Survivin at both mRNA and protein levels. The decreased cisplatin sensitivity/apoptosis induced by ectopic AATF were reversed after treatment with Survivin inhibitor YM155.
Conclusion:
Our results showed that AATF was overexpressed in human bladder cancers and promoted malignant behavior by regulating cyclin E and Survivin, indicating AATF could serve as a malignant biomarker and potential therapeutic target in BC.
Insights
Apoptosis antagonizing transcription factor (AATF) is upregulated in bladder cancer, promoting tumor growth and cisplatin resistance by regulating cyclin E and Survivin. AATF may serve as a biomarker and therapeutic target for bladder cancer.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Research
Background:
- Dysregulation of apoptosis antagonizing transcription factor (AATF) is linked to various human cancers.
- The role of AATF in human bladder cancer (BC) has not been previously investigated.
Purpose of the Study:
- To investigate the clinical significance of AATF in human bladder cancer.
- To elucidate the biological roles and underlying mechanisms of AATF in bladder cancer cells.
Main Methods:
- Immunohistochemistry on 107 bladder cancer tissues.
- AATF plasmid transfection and siRNA knockdown in T24 and 5637 cell lines.
- Cell viability (CCK-8), colony formation, apoptosis (Annexin V/PI), mitochondrial membrane potential (JC-1), and Western blotting assays were performed.
Main Results:
- AATF expression was significantly upregulated in bladder cancer tissues and cell lines, correlating with T stage and poor patient survival (TCGA data).
- Ectopic AATF expression enhanced cell proliferation and colony formation, decreased cisplatin sensitivity, and inhibited apoptosis by upregulating cyclin E and Survivin.
- AATF knockdown reversed these effects, and AATF-mediated cisplatin resistance was reversed by a Survivin inhibitor.
Conclusions:
- AATF is overexpressed in human bladder cancer and promotes malignant behaviors.
- AATF regulates cyclin E and Survivin, contributing to tumor progression and chemoresistance.
- AATF represents a potential diagnostic biomarker and therapeutic target for bladder cancer.
Related Concept Videos
01:12Loss of Tumor Suppressor Gene Functions
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...
01:31The Intrinsic Apoptotic Pathway