Aethlon Medical Inc (AEMD)

[ANESRI]

Tumor Exosomes Promote Metastatic Dissemination by Reprogramming Bone Marrow Cells

http://www.hematology.org/Publications/Hematologist/2012/8895.aspx

While the specifics are intriguing, more broadly, the study hints at the complexity of the cargo carried by tumor exosomes, suggesting an enormous potential to directly influence the biology of the tumor microenvornment. The experiments also identify another part of the multi-compartmental physiology of metastatic cancer by demonstrating that exosome trafficking alters the malignant phenotype and transcends conventional paracrine signaling by direct cytoplasmic transfer of a receptor tyrosine kinase. Even though experimentally feasible, global interference with exosome release as a constitutive cellular function is too broad a therapeutic target. Going forward, we can anticipate that discovery-driven proteomic or transcriptomic analyses will dissect the molecular events that result from vesicle trafficking in the tumor and bone marrow microenvironment and lead to the identification of more suitable therapeutic targets.

Peinado and colleagues provide persuasive evidence that tumor-derived exosomes promote melanoma metastasis by activating cells in the bone marrow and prompting the formation of a “pre-metastatic” niche. Questions remain unanswered about the mechanism by which c-kit/Tie-2–expressing cells shape the microenvironment in the metastatic target tissue and about other cellular processes that are affected by the exosome transfer process. Nevertheless, this imaginative study has both diagnostic and therapeutic implications and should stimulate further research into the role of exosomes and their cellular targets in the bone marrow during the evolution and progression of cancer.