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Objective: To investigate the auto-induction of transforming growth factor-b1 (TGF-β1) in breast cancer stem cells (BCSCs) and its effect on cell viability and stemness., Methods: Human BCSCs (aldehyde dehydrogenase positive; ALDH+) were grown in serum-free Dulbecco's Modified Eagle Medium/Nutrient Mixture F12 (DMEM/F12) and treated for periods of 1, 2 and 4 hours with 0.1 ng/ml recombinant human TGF-β1 protein (rhTGF-β1). The medium was then replaced with serum-free DMEM/F12 without rhTGF-β1 for 24 hours. Cell viability was determined using a trypan blue exclusion assay. Type 1 TGF-β receptor (TβR1), TGF-β1, octamer-binding transcription factor 4 (OCT4) and aldehyde dehydrogenase 1 family member A1 (ALDH1A1) messenger RNA (mRNA) expression levels were analysed using quantitative real-time reverse-transcriptase polymerase chain reaction (RT-qPCR). The TGF-β protein level in the culture medium was determined using an enzyme-linked immunosorbent assay (ELISA)., Results: The expression levels of rhTGF-β1, TGF-β1 and TβR1 mRNA significantly increased in BCSCs compared to control after treatment for 1 and 2 hours but decreased after 4 hours. This is in line with alteration of stemness gene, OCT4 and ALDH1A1 mRNA expressions. However, the secretion of newly synthesised TGF-β1 significantly increased after 2 hours. In contrast, viable BCSCs decreased after 1 hour and then gradually increased 2.7 times compared to control after 4 hours., Conclusions: TGF-β1 treatment in low concentration and for short period of time triggers its auto-induction in BCSCs, leading to increased cell viability and stemness gene expression via autocrine signalling.

Objective: The aim of this study was to investigate the effect of cancer-associated fibroblasts (CAF) secretomes on the epithelial-mesenchymal transition (EMT) of colorectal carcinoma (CRC) cells and its association with hepatocyte growth factor (HGF) signalling focussing on the HGF receptor, c-Mesenchymal epithelial transition (c-Met), and the EMT markers, vimentin and e-cadherin, in CRC cells., Methods: Conditioned mediums (CM) containing secretomes from colorectal CAFs and their counterpart normal fibroblasts (NFs) of three CRC patients were collected and supplemented to the HT-29 CRC cells. The mRNA levels of a-smooth muscle actin (a-SMA) and HGF in both fibroblasts, as well as c-Met, vimentin, and e-cadherin in HT-29 cells after supplemented with CAF- and NF-CM were determined using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). HGF protein level in the CM of CAFs and NFs was measured using enzyme-linked immunosorbent assay (ELISA). Vimentin and e-cadherin protein expressions were observed in HT-29 cells using immunofluorescent (IF) staining., Results: Compared to the non-cancerous colon, fibroblasts from cancerous area of CRC substantially expressed higher mRNA levels of a-SMA, a CAF marker. The HGF mRNA expressions in CAFs and NFs were in line with the HGF protein level in the secretomes of both cells. CAF-CM increased c-Met and vimentin mRNA levels in HT-29 cells. Surprisingly, e-cadherin mRNA level in HT-29 cells was increased following CAF-CM supplementation. We also demonstrated the co-localization of e-cadherin and vimentin in the HT-29 cell cytoplasm., Conclusions: CAF secretomes of CRC promote a hybrid type of EMT associated with HGF signalling.