FOSL1 promotes tumor growth and invasion in ameloblastoma

Gan Xiong; Shengqi Ouyang; Nan Xie; Jiaxiang Xie; Wenjin Wang; Chen Yi; Ming Zhang; Xiuyun Xu; Demeng Chen; Cheng Wang

doi:10.3389/fonc.2022.900108

FOSL1 promotes tumor growth and invasion in ameloblastoma

Front Oncol. 2022 Sep 15:12:900108. doi: 10.3389/fonc.2022.900108. eCollection 2022.

Authors

Gan Xiong^{1

2

3}, Shengqi Ouyang^{1

2

3}, Nan Xie^{1

2

3}, Jiaxiang Xie^{1

2

3}, Wenjin Wang^{1

2

3}, Chen Yi^{1

2

3}, Ming Zhang^{1

2

3}, Xiuyun Xu^{1

2

3}, Demeng Chen⁴, Cheng Wang^{1

2

3}

Affiliations

¹ Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.
² Guangdong Provincial Key Laboratory of Stomatology, Sun Yatsen University, Guangzhou, China.
³ Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China.
⁴ Center for Translational Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.

Abstract

Background: FOSL1, a key component of the Activating protein-1 (AP-1) transcriptional complex, plays an important role in cancer cell migration, invasion, and proliferation. However, the impact of FOSL1 in ameloblastoma (AM) has not been clarified. Herein, we aimed to assess the expression of FOSL1 and investigate its functional role in AM.

Methods: The expression of FOSL1 was examined based on an immunohistochemistry analysis of 96 AM samples. Cell proliferation, migration, invasion, and tumorigenesis were assessed using Cell Counting Kit-8 (CCK-8), colony formation, Transwell, and sphere formation assays. RNA sequencing (RNA-seq) was employed to investigate the molecular alterations of AM cells upon FOSL depletion. Microarrays of AMs were downloaded from the Gene Expression Omnibus (GEO) database for bioinformatics analysis. In addition, patient-derived AM organoids were used to evaluate the therapeutic value of the AP-1 inhibitor.

Results: FOSL1 was detected in the nuclei of AMs and upregulated in conventional AMs compared to unicystic AMs and normal oral epithelium. Compared with primary AM, FOSL1 expression was significantly increased in recurrent AM. Genetic knockdown of FOSL1 suppressed the proliferation, migration, invasion, and sphere formation of AMs. Similar results were also observed by pharmacological inhibition of AP-1 activity. Moreover, the AP-1 inhibitor T5224 impeded the growth of organoids derived from AM patients. Mechanistically, our Ingenuity Pathway Analysis (IPA) and gene set enrichment analysis (GSEA) results revealed that depletion of FOSL1 inactivated kinetochore metaphase signaling and the epithelial-mesenchymal transition pathway and then impaired the aggressiveness of AM cells accordingly.

Conclusion: FOSL1 promotes tumor recurrence and invasive growth in AM by modulating kinetochore metaphase signaling and the epithelial-mesenchymal transition pathway; thus, it represents a promising therapeutic target for AM treatment.

Keywords: FOSL1; ameloblastoma; cell proliferation; epithelial-mesenchymal transition pathway; kinetochore metaphase signaling.