Mesenchymal stem cell-derived extracellular vesicles may promote breast cancer cell dormancy

Disseminated breast cancer cells have the capacity to metastasise to the bone marrow and reside in a dormant state within the mesenchymal stem cell (MSC) niche. Research has focussed on paracrine signalling factors, such as soluble proteins, within the microenvironment. However, it is now clear extracellular vesicles (EVs) secreted by resident MSCs into this microenvironment also play a key role in the initiation of dormancy. Dormancy encourages reduced cell proliferation and migration, whilst upregulating cell adhesion, thus retaining the cancer cells within the bone marrow microenvironment. Here, MCF7 breast cancer cells were treated with MSC-derived EVs, resulting in reduced migration in 2D and 3D culture, with reduced cell proliferation and enhanced adhesion, collectively supporting cancer cell dormancy

Mesenchymal stem cell-derived extracellular vesicles may promote breast cancer cell dormancy

Disseminated breast cancer cells have the capacity to metastasise to the bone marrow and reside in a dormant state within the mesenchymal stem cell (MSC) niche. Research has focussed on paracrine signalling factors, such as soluble proteins, within the microenvironment. However, it is now clear extracellular vesicles (EVs) secreted by resident MSCs into this microenvironment also play a key role in the initiation of dormancy. Dormancy encourages reduced cell proliferation and migration, whilst upregulating cell adhesion, thus retaining the cancer cells within the bone marrow microenvironment. Here, MCF7 breast cancer cells were treated with MSC-derived EVs, resulting in reduced migration in 2D and 3D culture, with reduced cell proliferation and enhanced adhesion, collectively supporting cancer cell dormancy

Physical-chemical properties of the GNPs employed in the study.

<p>Physical-chemical properties of the GNPs employed in the study.</p

Effect of photoperiod and high fat diet (HFD) on hypothalamic expression of genes involved in energy balance growth in juvenile F344 rats 4 weeks of treatment, measured by quantitative in situ hybridisation.

<p>(a) <i>AgRP</i> mRNA expression quantified in the ARC was lower in SD than LD chow fed rats (p<0.001). The HFD had no effect in LD but reduced the <i>AgRP</i> levels further than chow fed rats in SD (p = 0.001). (b) <i>CRH</i> mRNA expression in the PVN was higher in SD than LD chow (p = 0.044) and HFD rats (p = 0.022). The HFD did not impact further on the expression levels in either photoperiod. (c) <i>NPY</i> mRNA levels tended to increase in SD chow fed rats in the ARC but the level did not reach significance (p = 0.119). There were no effects of HFD on <i>NPY</i> expression in either photoperiod. (d) <i>POMC</i> mRNA expression in the ARC is outlined and marked by arrows while atypical <i>POMC</i> expression in the ependymal layer of the 3^rd ventricle is marked by an arrowhead. In the ARC, <i>POMC</i> levels were unaffected by photoperiod or diet. In contrast, levels of <i>POMC</i> mRNA were markedly reduced in SD photoperiod (p<0.001) with no additional effects of HFD feeding. (e) <i>GHRH</i> mRNA expression in the ARC was lower in SD than LD chow fed rats. HFD reduced the <i>GHRH</i> expression in LD and even further in SD. Scale bar = 1.0mm for all images.</p

Effect of photoperiod and high fat diet (HFD) on gene expression of <i>TSHβ</i> and <i>NMU</i> in the pars tuberalis of the pituitary and Dio2 and Dio3 in the tanycytes around the third ventricle in juvenile F344 rats after 4 weeks of treatment.

<p>Gene expression was measured by quantitative in situ hybridisation. (a,b) Expression of <i>TSHβ</i> (a) and <i>NMU</i> (b) mRNAs in the pars tuberalis were significantly lower in both chow and HFD fed SD compared to LD rats. (c) <i>Dio2</i> mRNA levels in the ependymal cells around the 3^rd ventricle were lower in SD than LD chow and HFD fed rats (p<0.001). HFD reduced Dio2 further in SD compared to LD conditions (p<0.001). (d) <i>Dio3</i> mRNA expression was higher in SD than LD rats. HFD increased the <i>Dio3</i> mRNA level significantly in SD (p<0.001), but not in LD.</p

In cell western data of osterix protein levels.

<p>(A) at day 5 in MG63s after 48 hours incubation with GNP treatments normalised to cell number and to PEG GNPs, and in MCF-7 cells (n = 6; error bars denote standard deviation); (B) at day 7 in MSCs after 48 hours incubation with GNP treatments normalized to cell number and to PEG GNPs. (n = 6; error bars denote standard error, **** = p<0.0001; *** = p<0.001; ** = p<0.01 compared to no GNPs).</p

Effect of photoperiod and high fat diet (HFD) on body weight, food, protein and energy intake and body fatness of juvenile F344 rats over 4 weeks of treatment.

<p>(a) Body weight was significantly higher in LD compared to SD (p<0.001) on chow diet with no effect of a HFD after 4 weeks. (b) Food intake in grams was significantly higher in LD than SD on chow diet (p<0.001) and these intakes were higher than the intakes of the HFD fed rats (p<0.001). There was a small photoperiodic difference in food intake when fed the HFD (p = 0.03). (c) Protein intake was higher in the LD than the SD chow fed rats (p<0.001). HFD fed rats showed lower protein intakes than the chow fed rats (LD; p<0.001, SD; p = 0.008) and there was a significant effect of photoperiod (p = 0.015). (d) Energy intakes were higher in LD than SD rats fed either chow (p<0.001) or HFD (p = 0.004), while rats fed the HFD had higher energy intakes than chow in both photoperiods (p<0.001). (e) Fat mass measured by Echo MRI was slightly higher in LD than SD rats on chow (p = 0.026), while the HFD fed rats did not differ in their intakes with photoperiod. The HFD fed rats had markedly higher fat masses that were significantly higher than chow fed rats (p<0.001). (f) A HFD markedly increased adiposity as a percentage of body weight compared to chow fed rats and to a similar level in rats on both LD and SD (p<0.001) with no effect of photoperiod. In all figures HF refers to HFD fed rats.</p

Effect of photoperiod and high fat diet (HFD) on hormone and metabolites levels in juvenile F344 rats after 4 weeks of treatment.

<p>(a-c): (a) serum Leptin, (b) plasma NEFA and (c) plasma Triglyceride levels were not changed by photoperiod but were significantly higher in HFD fed rats in both photoperiods (all p<0.05). (d) Glucose levels were unchanged with diet or photoperiod.</p

Effect of photoperiod and high fat diet (HFD) on serum IGF-1 and pituitary growth hormone (GH) levels in juvenile F344 rats after, 4 weeks of treatment.

<p>(a) IGF-1 levels in serum were lower in SD chow and HFD fed rats than LD chow fed while LD HFD fed rats were not significantly different. (b) Growth hormone levels in the pituitary were unaffected by either photoperiod or HFD.</p

Fluidigm analysis.

<p>Heat-Map of (A) MG63s and (B) MSCS treated with the GNPs for 48 hours (green reflects a decrease in expression, whilst red reflects an increase). The data was analysed using PermutMatrix and ordered into hierarchy based on expression similarity.</p