The crosstalk within tumor microenvironment and exosomes in pancreatic cancer

Pancreatic cancer is one of the most malignant tumors with a grim prognosis. Patients develop chemoresistance that drastically decreases their survival. The chemoresistance is mainly attributed to deficient vascularization of the tumor, intratumoral heterogeneity and pathophysiological barrier due to the highly desmoplastic tumor microenvironment. The interactions of cells that constitute the tumor microenvironment change its architecture into a cancer-permissive environment and stimulate cancer development, metastasis and treatment response. The cell-cell communication in the tumor microenvironment is often mediated by exosomes that harbour a diverse repertoire of molecular cargo, such as proteins, lipids, and nucleic acid, including messenger RNAs, non-coding RNAs and DNA. Therefore, exosomes can serve as potential targets as biomarkers and improve the clinical management of pancreatic cancer to overcome chemoresistance. This review critically elucidates the role of exosomes in cell-cell communication within the tumor microenvironment and how these interactions can orchestrate chemoresistance.