Targeting exosomes from preadipocytes inhibits preadipocyte to cancer stem cell signaling in early-stage breast cancer

Abstract

The tumor microenvironment plays a critical role in regulating breast tumor progression. Signaling between preadipocytes and breast cancer cells has been found to promote breast tumor formation and metastasis. Exosomes secreted from preadipocytes are important components of the cancer stem cell niche. Mouse preadipocytes (3T3L1) are treated with the natural antitumor compound shikonin (SK) and exosomes derived from mouse preadipocytes are co-cultured with MCF10DCIS cells. We examine how preadipocyte-derived exosomes can regulate early-stage breast cancer via regulating stem cell renewal, cell migration, and tumor formation. We identify a critical miR-140/SOX2/SOX9 axis that regulates differentiation, stemness, and migration in the tumor microenvironment. Next, we find that the natural antitumor compound SK can inhibit preadipocyte signaling inhibiting nearby ductal carcinoma in situ (DCIS) cells. Through co-culture experiments, we find that SK-treated preadipocytes secrete exosomes with high levels of miR-140, which can impact nearby DCIS cells through targeting SOX9 signaling. Finally, we find that preadipocyte-derived exosomes promote tumorigenesis in vivo, providing strong support for the importance of exosomal signaling in the tumor microenvironment. Our data also show that targeting the tumor microenvironment may assist in blocking tumor progression.

A High-Fat Diet Promotes Mammary Gland Myofibroblast Differentiation through MicroRNA 140 Downregulation

“…In estrogen receptorpositive breast cancer, miR-140 is downregulated due to estrogen-mediated transcriptional inhibition, whereas in basal-like breast cancers, epigenetic mechanisms of inhibition have been demonstrated (20)(21)(22). We have shown that miR-140 is highly expressed in preadipocytes (23) and is necessary for adipose-derived stem cell adipogenesis under normal physiological conditions (24). Although several studies have observed that miR-140 targets TGF-␤1 signaling through SMAD3 and TGF-␤1 receptor 1 (TGFBR1) mRNA degradation via binding to their 3= UTRs and that upregulation of miR-140 inhibits TGF-␤1 signaling in lung tissue (25), the mechanism for the loss of the miR-140 protection pathway in obesity and fibrosis is unknown.…”

“…Adipocytes from obese individuals actively shed miRNAcontaining exosomes (35), which may affect signaling in nearby cells. We have previously shown that exosomes secreted by preadipocytes contain high levels of miR-140 and that treatment with shikonin can induce high levels of miR-140 in preadipocyte exosomes (23). The use of miR-140-promoting drugs such as shikonin or paclitaxel may be a novel therapeutic microenvironmental targeting strategy for the prevention of fibrosis and its associated diseases.…”

MicroRNA 140 Promotes Expression of Long Noncoding RNA NEAT1 in Adipogenesis

“…Cell culture, reagents, transfection, and actinomycin D. MCF10DCIS (DCIS) breast cancer cells obtained from Asterand (Detroit, MI) and murine 3T3-L1 preadipocytes and human lung fibroblasts obtained from the ATCC were cultured as previously described (17,29). Human mammary preadipocytes (mammary adipocyte precursor cells) were purchased from ZenBio (Research Triangle Park, NC) and were maintained and differentiated as described previously (30).…”

Extracellular vesicles as regulators of tumor fate: crosstalk among cancer stem cells, tumor cells and mesenchymal stem cells

“…Recently, Bourkoula et al (74) demonstrated the potential of exosomes released by glioma-associated non-tumorigenic stem cells (GASC) to enhance the migration capacity and anchorage-independent growth of glioma CSCs. Moreover, Gernapudi et al (75) showed that breast pre-adipocytes can enhance mammosphere formation by DCIS stemlike cells in vitro and tumor growth in vivo. Interestingly, mouse preadipocytes treated with shikonin, a natural antitumorigenic compound, generated exosomes unable to support CSC growth.…”