Pleural mesothelioma is both one of the most aggressive forms of cancer and also largely non-responsive to treatment. To identify therapeutic targets, researchers from the IRCCS Humanitas Research Hospital in Milan, Italy, recently investigated a protein called glycoprotein non-metastatic melanoma protein B (GPNMB), which is secreted by tumor-associated macrophages. Their research confirmed that the protein’s presence in mesothelioma tumors is associated with lower survival, and that lab animals with low levels of the protein experienced significantly slower tumor progression.
Protein Released by Tumor-Associated Macrophages Linked to Mesothelioma Progression
Previous research has established that GPNMB plays an important role in cell adhesion, migration, differentiation, and growth, and that the protein plays a significant role in disease progression in other types of cancers. The Italian scientists set out to see whether the same was true in mesothelioma. They took cell samples from patients with malignant pleural mesothelioma to measure RNA and protein levels of GPNMB and then studied its functional role in mouse models.
This analysis revealed that in both human and lab animal pleural mesothelioma tissues, GPNMB is produced by the infiltrating Tumor-Associated Macrophages (TAMs) that provide the cancer’s tumors with connective tissues and blood vessels. The researchers also found that GPNMB RNA levels in mesothelioma patients are associated with lower patient survival, and that lab animals that were unable to produce the protein experienced significantly slower tumor growth.
GPNMB Protein Plays an Important Role in Mesothelioma Growth
The study confirmed that high expression of GPNMB represents a poor prognostic factor in mesothelioma patients, and low expression of GPNMB is associated with better survival. Finding that the protein binds to the CD44 receptor that is expressed by tumors, the researchers neutralized CD44 with a blocking antibody and found that it resulted in a significant reduction in tumor growth in the laboratory. Based on this evidence, they suggest that therapies that neutralize CD44 may be an effective strategy in treating mesothelioma.
If you or someone you love has been diagnosed with mesothelioma, research holds the key to longer survival and better outcomes. For information on other strides being made in treating this aggressive form of cancer, contact the Patient Advocates at Mesothelioma.net today at 1-800-692-8608.
