Our previous studies have reported that the secretomes of umbilical cord- and adipose-derived mesenchymal stem cells (MSCs) affected the stemness properties of human breast CSCs (BCSCs). However, little is known about specific factors in MSC secretomes, particularly those from human exfoliated deciduous teeth, which involved in tumor aggressiveness such as stemness and proliferation of CSCs. This study aimed to evaluate the stemness and proliferation of human BCSCs after supplemented with heated secretomes of stem cells from human exfoliated deciduous teeth (SHED) to activate latent TGF-β1.
To collect SHED conditioned medium (SHED-CM) containing secretomes, SHED were grown in serum-free a-MEM for 24 and 48 hours, respectively. SHED-CM 24-h was then heated at 800C for 10 min. Human BCSCs (ALDH+) cultured in DMEM-F12 were supplemented with 50% (v/v) non-heated SHED-CM 24- and 48-h, as well as with heated SHED-CM 24-h followed by 72-h incubation. Control was BCSCs supplemented with non-heated 50% (v/v) a-MEM/DMEM-F12. Following the supplementation, we measured the mRNA expression of TGF-β1 receptor (TβRI), as well as stemness genes ALDH1A1 and OCT4 of BCSCs using qRT-PCR. BCSC proliferation was determined using trypan blue dye.
This study demonstrates that relative mRNA expression levels of TβRI, OCT4 and ALDH1A1 in BCSCs supplemented with non-heated SHED-CM 24- and 48-h were increased compared to their control. Interestingly, the increase of TβRI, OCT4 and ALDH1A1 expressions after TGF-β1 heat activation was significantly higher than in non-heated SHED-CM. Conversely, BCSC proliferation was significantly reduced after supplemented with non-heated SHED-CM 24- and 48-h, but drastically increased higher than control when treated with heated SHED-CM 24-h, suggesting the involvement of other factors in SHED-CM that restrain TGF-β1 signaling and suppress cell proliferation.
Heated SHED secretomes contained activated TGF-β1 that increased the expression of stemness genes, OCT4 and ALDH1A1, as well as proliferation of human BCSCs (ALDH+) via TGF-β1 paracrine signaling.
Clinical trial identification
Legal entity responsible for the study
Septelia Inawati Wanandi.
Directorate of Research and Community Service, Universitas Indonesia.
All authors have declared no conflicts of interest.