Related Experiment Video
Updated: Jul 15, 2025
Cytotoxic Efficacy of Photodynamic Therapy in Osteosarcoma Cells In Vitro
Published on: March 18, 2014
A TLR4 Agonist Induces Osteosarcoma Regression by Inducing an Antitumor Immune Response and Reprogramming M2
Iseulys Richert1, Paul Berchard1, Lhorra Abbes1
1Cell Death and Pediatric Cancers Team INSERM U1052, CNRS UMR 5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon, 69373 Lyon, France.
Abstract:
Osteosarcoma (OsA) has limited treatment options and stagnant 5-year survival rates. Its immune microenvironment is characterized by a predominance of tumor-associated macrophages (TAMs), whose role in OsA progression remain unclear. Nevertheless, immunotherapies aiming to modulate macrophages activation and polarization could be of interest for OsA treatment. In this study, the antitumor effect of a liposome-encapsulated chemically detoxified lipopolysaccharide (Lipo-MP-LPS) was evaluated as a therapeutic approach for OsA. Lipo-MP-LPS is a toll-like receptor 4 (TLR4) agonist sufficiently safe and soluble to be IV administered at effective doses. Lipo-MP-LPS exhibited a significant antitumor response, with tumor regression in 50% of treated animals and delayed tumor progression in the remaining 50%. The agent inhibited tumor growth by 75%, surpassing the efficacy of other immunotherapies tested in OsA. Lipo-MP-LPS modulated OsA's immune microenvironment by favoring the transition of M2 macrophages to M1 phenotype, creating a proinflammatory milieu and facilitating T-cell recruitment and antitumor immune response. Overall, the study demonstrates the potent antitumor effect of Lipo-MP-LPS as monotherapy in an OsA immunocompetent model. Reprogramming macrophages and altering the immune microenvironment likely contribute to the observed tumor control. These findings support the concept of immunomodulatory approaches for the treatment of highly resistant tumors like OsA.
Insights
Liposome-encapsulated detoxified lipopolysaccharide (Lipo-MP-LPS) shows potent antitumor effects in osteosarcoma models. This immunotherapy reprograms macrophages, enhancing the immune response against this resistant cancer.
Area of Science:
- Oncology
- Immunology
- Pharmacology
Background:
- Osteosarcoma (OsA) presents limited therapeutic options and poor survival rates.
- Tumor-associated macrophages (TAMs) dominate the OsA immune microenvironment, but their role is not fully understood.
- Immunotherapies targeting macrophage modulation offer potential for OsA treatment.
Purpose of the Study:
- To evaluate the antitumor efficacy of liposome-encapsulated chemically detoxified lipopolysaccharide (Lipo-MP-LPS) as a therapeutic strategy for osteosarcoma.
- To investigate the immunomodulatory effects of Lipo-MP-LPS on the osteosarcoma immune microenvironment.
Main Methods:
- Administration of Lipo-MP-LPS, a safe and soluble toll-like receptor 4 (TLR4) agonist, via intravenous injection in an immunocompetent osteosarcoma model.
- Assessment of tumor growth inhibition, regression rates, and survival.
- Analysis of immune cell populations and phenotypes within the tumor microenvironment, focusing on macrophage polarization and T-cell infiltration.
Main Results:
- Lipo-MP-LPS demonstrated significant antitumor activity, achieving 75% tumor growth inhibition.
- Complete tumor regression was observed in 50% of treated animals, with delayed progression in the remaining 50%.
- Lipo-MP-LPS treatment shifted macrophages from M2 to M1 phenotype, promoting a pro-inflammatory environment and enhancing T-cell-mediated antitumor immunity.
Conclusions:
- Lipo-MP-LPS exhibits potent monotherapy antitumor effects in an osteosarcoma model.
- Macrophage reprogramming and immune microenvironment modulation are key mechanisms underlying Lipo-MP-LPS efficacy.
- These findings support the development of immunomodulatory agents for treating refractory tumors like osteosarcoma.
More Related Videos
07:31A Syngeneic Orthotopic Osteosarcoma Sprague Dawley Rat Model with Amputation to Control Metastasis Rate
Published on: May 3, 2021
07:44Studying the Effects of Tumor-Secreted Paracrine Ligands on Macrophage Activation using Co-Culture with Permeable Membrane Supports
Published on: November 28, 2019
