Exosomes Secreted from Human Cancer Cell Lines Contain Inhibitors of Apoptosis (IAP)

Abstract

Exosomes are endosomal-derived nanovesicles released by normal and tumor cells which have been shown to transfer functionally active protein, lipids, mRNAs and miRNAs between cells. Varying in molecular profiles, biological roles, functional roles and protein contents, exosomes have been described as Bmulti-purpose carriers^playing a role in supporting the survival and growth of tumor cells. The IAP Survivin has been found to be present in tumor exosomes. However, the existence of other IAPs in tumor exosomes is still unknown. Survivin, cIAP1, cIAP2 and XIAP mRNA and protein are differently expressed in a panel of tumor cell lines: DLCL2, HeLa, MCF-7, Panc-1, and PC3. Exosomes were isolated from conditioned media collected from the cells from which RNA and protein were extracted. Our results provide evidence that like Survivin, XIAP, cIAP1 and cIAP2 proteins are found in tumor exosomes. The mRNA expression, however, is differentially expressed across the tumor cell lines. The presence of these bioactive molecules in exosomes may not only serve as warning signals, but also play a role in providing protection to the cancer cells against changes that are constantly occurring in the tumor microenvironment.

Pathogenic role of exosomes and microRNAs in HPV‐mediated inflammation and cervical cancer: A review

“…Survivin‐positive exosomes were further examined to detect stress‐induced proteins within the cargo. In our study, inhibitor of apoptosis proteins (IAPs), including XIAP, c‐IAP1, c‐IAP2 and livin/ML‐IAP, was demonstrated . The presence of IAPs was dependent on HPV oncoproteins, because the exosomes derived from HeLa cells in which the E6‐ and E7‐proteins had been silenced had less IAPs, although these silenced cells exhibited greater overall exosome secretion compared to control cells .…”

Inhibition of apoptosis using exosomes in Chinese hamster ovary cell culture

“…For instance, Inhibitors of apoptosis proteins (IAPs) are known to be secreted from cancer cells via exosomes and those exosomes can be taken up by other cells (Valenzuela et al, 2015). For instance, Inhibitors of apoptosis proteins (IAPs) are known to be secreted from cancer cells via exosomes and those exosomes can be taken up by other cells (Valenzuela et al, 2015).…”

Proteomic Profiling of Serum-Derived Exosomes from Ethnically Diverse Prostate Cancer Patients

“…Exosomes play an important part in this communication due to their ability to transport cancer-promoting material such as protein, RNA and miRNA (14–16). In order to successfully treat cancer, it will be crucial to develop therapeutic strategies that not only target tumor cells but also the mediators within the tumor microenvironment that modulated many aspects of the etiology of this disease (17–19). However, enhanced treatment capabilities are the direct result of earlier detection which will depend significantly on the early discovery of biomarkers shed by these tumors (20).…”