Small extracellular vesicles modulated by αVβ3 integrin induce neuroendocrine differentiation in recipient cancer cells

Abstract

The ability of small extracellular vesicles (sEVs) to reprogram cancer cells is well established. However, the specific sEV components able to mediate aberrant effects in cancer cells have not been characterized. Integrins are major players in mediating sEV functions. We have previously reported that the αVβ3 integrin is detected in sEVs of prostate cancer (PrCa) cells and transferred into recipient cells. Here, we investigate whether sEVs from αVβ3-expressing cells affect tumour growth differently than sEVs from control cells that do not express αVβ3. We compared the ability of sEVs to stimulate tumour growth, using sEVs isolated from PrCa C4-2B cells by iodixanol density gradient and characterized with immunoblotting, nanoparticle tracking analysis, immunocapturing and single vesicle analysis. We incubated PrCa cells with sEVs and injected them subcutaneously into nude mice to measure in vivo tumour growth or analysed in vitro their anchorage-independent growth. Our results demonstrate that a single treatment with sEVs shed from C4-2B cells that express αVβ3, but not from control cells, stimulates tumour growth and induces differentiation of PrCa cells towards a neuroendocrine phenotype, as quantified by increased levels of neuroendocrine markers. In conclusion, the expression of αVβ3 integrin generates sEVs capable of reprogramming cells towards an aggressive phenotype.

Differential expression of αVβ3 and αVβ6 integrins in prostate cancer progression

“…We can speculate that upon RB1 loss, downregulation of αVβ6 and gain of the αVβ3 integrin are required in the primary tumors in the early stages of NED to confer upon NEPrCa the ability to metastasize in different sites ( Fig 6 ). Upon metastasizing, the αVβ3 integrin expression is sustained as shown here and as previously described [ 7 ] in NEPrCa bone metastasis, indicating additional pro-survival functions provided by this integrin.…”

“…In a recent study, we have shown that the αVβ3 integrin is found in small extracellular vesicles released by cancer cells and that small extracellular vesicles containing αVβ3 have a unique ability to promote NED of PrCa in vivo [ 7 ]. Based on these findings, we hypothesized that elevated expression levels of αVβ3 might correlate with NED in PrCa.…”

“…Our previous study demonstrates that the dysregulated expression of the αVβ3 integrin in small extracellular vesicles released by PrCa cells promotes a shift in lineage plasticity towards a NE lineage [ 7 ]. Moreover, although our group has reported that the αVβ6 integrin, in small extracellular vesicles released by cancer cells, induces M2 polarization in recipient monocytes [ 64 ] and stimulates angiogenesis in endothelial cells during cancer progression [ 65 ], is absent in NEPrCa.…”

“…Integrins are transmembrane adhesion receptors that are deregulated during cancer progression [ 1 , 2 ]. Among others, αVβ6, αVβ3, α6β1, and α6β4 integrins are overexpressed in in prostate cancer (PrCa) [ 3 – 6 ]; our group recently demonstrated that small extracellular vesicles released from PrCa cells and containing the αVβ3 integrin induce neuroendocrine differentiation (NED) in vitro and in vivo [ 7 ]. In contrast, the α5 and α7 integrin subunits have been reported to be downregulated in PrCa [ 8 ].…”

“…The αVβ3 integrin itself is involved in a variety of processes, including angiogenesis and tumor metastasis [ 16 ]. While present at very low levels in normal prostate tissues, it is highly expressed in PrCa cells and in metastasis [ 7 , 10 , 17 ]. Given its widespread distribution in PrCa, αVβ3 has been explored as a therapeutic target in some studies [ 18 , 19 ].…”