Involvement of MM cell‑derived exosomes in T lymphocytes immune responses

Abstract

Exosomes were reported to mediate cell communication in the tumor microenvironment; however, the effects of multiple myeloma (MM)-derived exosomes on the quantity and function of T cells remain unknown. Exosomes were extracted from MM cell lines (OPM2 and U266B1) by ultracentrifugation using a Total Exosome Isolation kit. Exosomes were co-cultured with CD4+ T, CD8+ T and regulatory T (Treg) cells that were isolated from healthy donors (HDs) and patients with MM using magnetic beads. Flow cytometry was used to detect T cells apoptosis and expression of perforin and granzyme B in CD8+ T cells. Cell viability was detected using Cell Counting kit-8, and interleukin 10 (IL-10) and transforming growth factor β (TGF-β) in cell supernatants were detected by ELISA. The apoptosis of HD-CD4+ T was higher in the OPM2 group, and viability in the U266B1 group was decreased. The apoptosis of HD-CD8+ T decreased in the OPM2 and U266B1 groups, and cell viability increased in the OPM2 and the U266B1 groups. Perforin of HD-CD8+ T in the U266B1 group was lower while perforin of MM-CD8+ T in OPM2 and U266B1 groups was markedly decreased. The apoptosis of HD-Treg was lower in the U266B1 group, but apoptosis of MM-Treg was higher in the U266B1 group. The viability of HD-Treg in U266B1 group increased but the viability of MM-Treg in OPM2 and U266B1 groups decreased. TGF-β from MM-Treg decreased in the OPM2 and U266B1 groups when compared with the control group (P<0.05). MM-derived exosomes promote apoptosis and inhibit proliferation of HD-CD4+ T, inhibit apoptosis and promote proliferation, but inhibit perforin of HD-CD8+ T, inhibit apoptosis and promote proliferation HD-Treg, and inhibit perforin of MM-CD8+ T and TGF-β secretion of MM-Treg.

Circulating extracellular vesicles expressing PD1 and PD-L1 predict response and mediate resistance to checkpoint inhibitors immunotherapy in metastatic melanoma

“…The plate was then transferred to an incubator (37 °C, 5% CO 2 ). Two days later, the LND1 spheroids (about 1 × 10 5 cells) were treated with 1 × 10 5 PKH26 green-PBMCs, preincubated for 1 h with 100 μg PKH67 red-EVs [ 37 ], with or without 20 μg/ml nivolumab (Selleck Chemical, Selleck USA). Each experimental condition was in triplicate.…”

Emerging role of tumor-derived extracellular vesicles in T cell suppression and dysfunction in the tumor microenvironment

“…85 Likewise, exosomes derived from multiple myeloma similarly mediate T cell suppression through both promoting proliferation of Treg cells and decreasing viability of CD4 + T cells. 86 T cell suppression mediated by tumor-derived exosomes is clearly linked to the pathogenesis and disease progression of cancers. Recent study has explored the effects of PD-L1 + tumor-derived exosomes isolated from HNSCCs on immune suppression and disease progression.…”

“… 85 Likewise, exosomes derived from multiple myeloma similarly mediate T cell suppression through both promoting proliferation of Treg cells and decreasing viability of CD4 + T cells. 86 …”

Exosomes in multiple myeloma: from bench to bedside

“…However, the cytotoxic capacity of these CD8+ T cells was decreased. Furthermore, the viability of HD Tregs increased, indicating that MM exosomes alter T cell phenotype to a more suppressive profile 50 .…”