Down-regulation of tumor endothelial marker 8 suppresses cell proliferation mediated by ERK1/2 activity

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Tumor endothelial marker 8 (TEM8) is a potential anti-tumor target due to its overexpression in various human cancers.
• Understanding TEM8's role in specific cancers like osteosarcoma is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate the functional significance of TEM8 in osteosarcoma.
• To determine the correlation between TEM8 expression levels and patient survival rates.

Main Methods:

• TEM8 expression analysis in osteosarcoma tissues, benign bone lesions, and adjacent non-tumor tissues.
• TEM8 knockdown using siRNA and shRNA in osteosarcoma cell lines.
• In vitro and in vivo assays to assess cell growth and proliferation.
• Western blot analysis to evaluate the impact on cell cycle regulatory proteins (p21, p27, cyclin D1) and Erk1/2 signaling pathway.

Main Results:

• TEM8 was found to be upregulated in osteosarcoma compared to benign bone lesions and adjacent non-tumor tissues.
• Higher TEM8 expression was significantly associated with a lower overall survival rate in osteosarcoma patients.
• Knockdown of TEM8 markedly reduced osteosarcoma cell proliferation both in vitro and in vivo.
• TEM8 ablation increased p21 and p27 expression and suppressed cyclin D1, mediated by Erk1/2 activity.

Conclusions:

• TEM8 is upregulated in osteosarcoma and serves as a prognostic biomarker for patient survival.
• Down-regulation of TEM8 inhibits osteosarcoma cell growth and proliferation.
• TEM8 influences osteosarcoma tumorigenesis and progression through modulation of cell cycle regulators via the Erk1/2 pathway.