The fusion gene LRP1-SNRNP25 drives invasion and migration by activating the pJNK/37LRP/MMP2 signaling pathway in osteosarcoma

Peipei Xing; Haotian Liu; Wanyi Xiao; Gengpu Zhang; Chao Zhang; Zhichao Liao; Ting Li; Jilong Yang

doi:10.1038/s41420-024-01962-z

The fusion gene LRP1-SNRNP25 drives invasion and migration by activating the pJNK/37LRP/MMP2 signaling pathway in osteosarcoma

Cell Death Discov. 2024 Apr 27;10(1):198. doi: 10.1038/s41420-024-01962-z.

Authors

Peipei Xing^#^{1

2

3}, Haotian Liu^#^{1

2}, Wanyi Xiao^#^{1

2}, Gengpu Zhang^{1

2}, Chao Zhang^{1

2}, Zhichao Liao^{1

2}, Ting Li^{1

2}, Jilong Yang^{4

5}

Affiliations

¹ Department of Bone and Soft Tissue Tumor, Tianjin Medical University Cancer Institute & Hospital, Tianjin, 300060, PR China.
² National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute & Hospital, Tianjin, 300060, PR China.
³ Radiation Oncology Department, Tianjin Medical University General Hospital, Tianjin, 300052, PR China.
⁴ Department of Bone and Soft Tissue Tumor, Tianjin Medical University Cancer Institute & Hospital, Tianjin, 300060, PR China. yangjilong@tjmuch.com.
⁵ National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute & Hospital, Tianjin, 300060, PR China. yangjilong@tjmuch.com.

^# Contributed equally.

Abstract

Through transcriptome sequencing, we previously identified a new osteosarcoma-specific, frequent fusion gene, LRP1-SNRNP25, and found that it played an important role in tumor cell invasion and migration. However, the specific mechanism remains unclear. In this article, whole-genome sequencing further confirmed that the LRP1-SNRNP25 fusion gene is formed by fusion of LRP1 exon 8 and SNRNP25 exon 2. In vitro, scratch and Transwell assays demonstrated that the migration and invasion abilities of LRP1-SNRNP25-overexpressing osteosarcoma cells were significantly increased. To explore the molecular mechanism of the LRP1-SNRNP25 fusion in affecting osteosarcoma cell migration and invasion, we evaluated the migration and invasion-related molecular signaling pathways by western blotting. Some migration- and invasion-related genes, including pJNK and MMP2, were upregulated. Coimmunoprecipitation-mass spectrometry showed that 37LRP can interact with pJNK. Western blotting confirmed that LRP1-SNRNP25 overexpression upregulates 37LRP protein expression. Immunofluorescence staining showed the intracellular colocalization of LRP1-SNRNP25 with pJNK and 37LRP proteins and that LRP1-SNRNP25 expression increased the pJNK and 37LRP levels. Coimmunoprecipitation (co-IP) confirmed that LRP1-SNRNP25 interacted with pJNK and 37LRP proteins. The pJNK inhibitor SP600125 dose-dependently decreased the pJNK/37LRP/MMP2 levels. After siRNA-mediated 37LRP knockdown, the MMP2 protein level decreased. These two experiments proved the upstream/downstream relationship among pJNK, 37LRP, and MMP2, with pJNK the farthest upstream and MMP2 the farthest downstream. These results proved that the LRP1-SNRNP25 fusion gene exerts biological effects through the pJNK/37LRP/MMP2 signaling pathway. In vivo, LRP1-SNRNP25 promoted osteosarcoma cell growth. Tumor growth was significantly inhibited after SP600125 treatment. Immunohistochemical analysis showed that the pJNK, MMP2, and Ki-67 protein levels were significantly increased in tumor tissues of LRP1-SNRNP25-overexpressing cell-injected nude mice. Furthermore, lung and liver metastasis were more prevalent in these mice. In a word, LRP1-SNRNP25 promotes invasion, migration, and metastasis via pJNK/37LRP/MMP2 pathway. LRP1-SNRNP25 is a potential therapeutic target for LRP1-SNRNP25-positive osteosarcoma.