Theranostics 2020; 10(13):5719-5735. doi:10.7150/thno.42010 This issue Cite

Research Paper

Skipping of exon 10 in Axl pre-mRNA regulated by PTBP1 mediates invasion and metastasis process of liver cancer cells

Lianghua Shen1,2*, Sijia Lei1,2*, Bin Zhang1,2*, Shuaiguang Li1,2, Luyuan Huang3, Alexander Czachor4, Mason Breitzig4,5, Yuman Gao1, Meiyan Huang1, Xuemei Mo1, Qing Zheng1, Hanxiao Sun1*, Feng Wang1,2,4✉

1. Institute of Genomic Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, China.
2. International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of Education (MOE), College of pharmacy, Jinan University, Guangzhou 510632, China.
3. Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
4. Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd, MDC 19, Tampa, FL 33612, USA.
5. Brown School of Social Work, Washington University in St. Louis, St. Louis, MO, USA
* Lianghua Shen, Sijia Lei, Bin Zhang contributed equally to this work.

Citation:
Shen L, Lei S, Zhang B, Li S, Huang L, Czachor A, Breitzig M, Gao Y, Huang M, Mo X, Zheng Q, Sun H, Wang F. Skipping of exon 10 in Axl pre-mRNA regulated by PTBP1 mediates invasion and metastasis process of liver cancer cells. Theranostics 2020; 10(13):5719-5735. doi:10.7150/thno.42010. https://www.thno.org/v10p5719.htm
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Abstract

Graphic abstract

The Axl gene is known to encode for a receptor tyrosine kinase involved in the metastasis process of cancer. In this study, we investigated the underlying molecular mechanism of Axl alternative splicing.

Methods: The expression levels of PTBP1 in hepatocellular carcinoma (HCC) tissues were obtained from TCGA samples and cell lines. The effect of Axl-L, Axl-S, and PTBP1 on cell growth, migration, invasion tumor formation, and metastasis of liver cancer cells were measured by cell proliferation, wound-healing, invasion, xenograft tumor formation, and metastasis. Interaction between PTBP1 and Axl was explored using cross-link immunoprecipitation, RNA pull-down assays and RNA immunoprecipitation assays.

Results: Knockdown of the PTBP1 and exon 10 skipping isoform of Axl (Axl-S), led to impaired invasion and metastasis in hepatoma cells. Immunoprecipitation results indicated that Axl-S protein binds more robustly with Gas6 ligand than Axl-L (exon 10 including) and is more capable of promoting phosphorylation of ERK and AKT proteins. Furthermore, cross-link immunoprecipitation and RNA-pulldown assays revealed that PTBP1 binds to the polypyrimidine sequence (TCCTCTCTGTCCTTTCTTC) on Axl-Intron 9. MS2-GFP-IP experiments demonstrated that PTBP1 competes with U2AF2 for binding to the aforementioned polypyrimidine sequence, thereby inhibiting alternative splicing and ultimately promoting Axl-S production.

Conclusion: Our results highlight the biological significance of Axl-S and PTBP1 in tumor metastasis, and show that PTBP1 affects the invasion and metastasis of hepatoma cells by modulating the alternative splicing of Axl exon 10.

Keywords: Axl, alternative splicing, PTBP1, tumor metastasis, liver cancer cells


Citation styles

APA
Shen, L., Lei, S., Zhang, B., Li, S., Huang, L., Czachor, A., Breitzig, M., Gao, Y., Huang, M., Mo, X., Zheng, Q., Sun, H., Wang, F. (2020). Skipping of exon 10 in Axl pre-mRNA regulated by PTBP1 mediates invasion and metastasis process of liver cancer cells. Theranostics, 10(13), 5719-5735. https://doi.org/10.7150/thno.42010.

ACS
Shen, L.; Lei, S.; Zhang, B.; Li, S.; Huang, L.; Czachor, A.; Breitzig, M.; Gao, Y.; Huang, M.; Mo, X.; Zheng, Q.; Sun, H.; Wang, F. Skipping of exon 10 in Axl pre-mRNA regulated by PTBP1 mediates invasion and metastasis process of liver cancer cells. Theranostics 2020, 10 (13), 5719-5735. DOI: 10.7150/thno.42010.

NLM
Shen L, Lei S, Zhang B, Li S, Huang L, Czachor A, Breitzig M, Gao Y, Huang M, Mo X, Zheng Q, Sun H, Wang F. Skipping of exon 10 in Axl pre-mRNA regulated by PTBP1 mediates invasion and metastasis process of liver cancer cells. Theranostics 2020; 10(13):5719-5735. doi:10.7150/thno.42010. https://www.thno.org/v10p5719.htm

CSE
Shen L, Lei S, Zhang B, Li S, Huang L, Czachor A, Breitzig M, Gao Y, Huang M, Mo X, Zheng Q, Sun H, Wang F. 2020. Skipping of exon 10 in Axl pre-mRNA regulated by PTBP1 mediates invasion and metastasis process of liver cancer cells. Theranostics. 10(13):5719-5735.

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