Dynamicity of exosomes as immuno-oncological biomarkers in secondary
metastasis and cancer therapy
Abstract
Being a tiny component, all the intra-cellular orchestra starting from
exosome generation till its escape from the immune cells, is connected
with biogenic dynamicity of molecular signaling in the cells. The
biogenesis of exosomes follows the endocytic pathway thereby releases
the intraluminal vesicles in the extracellular space. Exosomes play
critical role in oncogenic signaling in the primary tumor
microenvironment as well as distant sites to make a pre-metastatic niche
(PMN) for the tumor cells to cause future metastasis. Moreover, tumor
derived exosomes (TDEs) play an important role in invasion-metastasis
cascade by initiating paracrine and autocrine signals in the tumor
milieu thus activating the epithelial–mesenchymal transition (EMT) in
the neoplastic epithelial cells. The exosomes taken up by the distally
situated organ tissues facilitates the formation of pre metastatic niche
allowing the tumor cells to arrive, extravasate and eventually colonize
in the new microenvironment and thereby promoting distant metastasis
(The Seed and Soil Theory). Importantly, secondary metastasis is also
achieved by altering the extracellular matrix by the TDEs as well as by
escaping the immune surveillance, which in turn modulate the host
immunity and gradually results in the disease progression. Exosomes
exhibiting the properties like high target specificity combined with low
immunogenicity and biocompatibility aids the exosomes to sow its seed in
the new field of therapies and thus all the remarkable properties make
it a focus of interest in the research field.