Notch signaling regulates osteosarcoma proliferation and migration through Erk phosphorylation

Area of Science:

• Oncology
• Molecular Biology
• Cell Biology

Background:

• Osteosarcoma is a highly metastatic bone cancer.
• Notch signaling is implicated in cancer development and progression.
• Identifying therapeutic targets for osteosarcoma is crucial for improving patient outcomes.

Purpose of the Study:

• To investigate the role of Notch signaling in osteosarcoma proliferation and migration.
• To elucidate the underlying molecular mechanisms of Notch signaling in osteosarcoma.
• To evaluate the therapeutic potential of inhibiting Notch signaling in osteosarcoma.

Main Methods:

• Utilized the K7M2 murine osteosarcoma cell line.
• Inhibited Notch activation using the γ-secretase inhibitor DAPT.
• Assessed cell proliferation, migration, apoptosis, and cell cycle using various assays (Sulforhodamine B, colony formation, BrdU, Ki67, flow cytometry, wound healing, Transwell).
• Analyzed Notch intracellular domain (NICD) and Phospho-Erk1/2 (p-Erk) expression via Western blotting.
• Investigated the Notch-Erk pathway interaction using Jagged1 and U0126.
• Evaluated DAPT efficacy in a K7M2 mouse para-tibial tumor and lung metastasis model.

Main Results:

• DAPT significantly inhibited K7M2 cell proliferation and migration in a dose-dependent manner.
• DAPT treatment led to decreased Notch1ICD and p-Erk expression.
• Jagged1-induced Notch activation up-regulated p-Erk, enhancing proliferation and migration.
• U0126-mediated Erk inhibition reduced proliferation and migration.
• In vivo, DAPT controlled tumor growth, reduced angiogenesis, decreased lung metastasis, and improved survival.
• DAPT altered key cell metabolism-related components in K7M2 cells.

Conclusions:

• Notch signaling acts as an oncogene in osteosarcoma, promoting metastasis through the Erk pathway.
• DAPT effectively inhibits osteosarcoma proliferation and metastasis both in vitro and in vivo.
• Inhibition of Notch activation and subsequent down-regulation of Erk phosphorylation represents a promising therapeutic strategy for osteosarcoma.