Metformin and soybean-derived bioactive molecules attenuate the expansion of stem cell-like epithelial subpopulation and confer apoptotic sensitivity in human colon cancer cells

Abstract

Colorectal cancer (CRC) is a disease whose genesis may include metabolic dysregulation. Cancer stem cells are attractive targets for therapeutic interventions since their aberrant expansion may underlie tumor initiation, progression, and recurrence. To investigate the actions of metabolic regulators on cancer stem cell-like cells (CSC) in CRC, we determined the effects of soybeanderived bioactive molecules and the anti-diabetes drug metformin (MET), alone and together, on the growth, survival, and frequency of CSC in human HCT116 cells. Effects of MET (60 lM) and soybean components genistein (Gen, 2 lM), lunasin (Lun, 2 lM), b-conglycinin (bcon, 3 lM), and glycinin (Gly, 3 lM) on HCT116 cell proliferation, apoptosis, and mRNA/protein expression and on the frequency of the CSC CD133 ? CD44 ? subpopulation by colonosphere assay and fluorescence-activated cell sorting/flow cytometry were evaluated. MET, Gen, and Lun, individually and together, inhibited HCT116 viability and colonosphere formation and, conversely, enhanced HCT116 apoptosis. Reductions in frequency of the CSC CD133 ? CD44 ? subpopulation with MET, Gen, and Lun were found to be associated with increased PTEN and reduced FASN expression. In cells under a hyperinsulinemic state mimicking metabolic dysregulation and without and with added PTEN-specific inhibitor SF1670, colonosphere formation and frequency of the CD133 ? CD44 ? subpopulation were decreased by MET, Lun and Gen, alone and when combined. Moreover, MET ? Lun ? Gen co-treatment increased the pro-apoptotic and CD133 ?-CD44 ? -inhibitory efficacy of 5-fluorouracil under hyperinsulinemic conditions. Results identify molecular networks shared by MET and bioavailable soy food components, which potentially may be harnessed to increase drug efficacy in diabetic and non-diabetic patients with CRC.

Lunasin is a novel therapeutic agent for targeting melanoma cancer stem cells

“…The activity of Lunasin both in vitro and in vivo on melanoma CICs suggests the intriguing possibility that Lunasin can target these quiescent and drug-resistant cells and is consistent with a recently published study on colon cancer [33]. These studies demonstrated that putative CICs isolated based on the expression of the surface markers CD133 and CD44 were sensitive to Lunasin and that this effect likely involves modulation of the PTEN/PI3K/FASN axis [33]. Taken in combination with our results, these data support a novel hypothesis that Lunasin and other soy derivatives have the ability to decrease cancer stem cell populations.…”

Metabolic history impacts mammary tumor epithelial hierarchy and early drug response in mice

“…For mammosphere formation assay, cells (2.5 × 10 3 cells/well) were plated in 6-well low-attachment plates after 24h Dox treatment and then evaluated for numbers of spheroids (mammospheres) 5 days later, in the absence of additional treatments, as previously described (Montales et al 2012). Cell viability using cells plated at an initial density of 2 × 10 5 per well was measured by the trypan blue exclusion method using the Vi-Cell cell viability analyzer (Beckman Coulter Inc., Atlanta, GA) (Montales et al 2015). The percent of apoptotic cells was evaluated 48h post-treatment by Annexin V staining (Trevigen, Gaithersburg, MD), followed by analyses using a Becton-Dickinson LSRFortessa Flow Cytometer (BD Biosciences, San Jose, CA) (Montales et al 2015).…”

“…Cell viability using cells plated at an initial density of 2 × 10 5 per well was measured by the trypan blue exclusion method using the Vi-Cell cell viability analyzer (Beckman Coulter Inc., Atlanta, GA) (Montales et al 2015). The percent of apoptotic cells was evaluated 48h post-treatment by Annexin V staining (Trevigen, Gaithersburg, MD), followed by analyses using a Becton-Dickinson LSRFortessa Flow Cytometer (BD Biosciences, San Jose, CA) (Montales et al 2015). For all assays, treatment effects were determined from three independent experiments in triplicates, with each experiment representing a distinct T-MEC isolation.…”

Targeting cancer stem cells with dietary phytochemical - Repositioned drug combinations

“…Synergy was found with paclitaxel and carboplatin in prostate and lung CSCs murine xenografts [101]. For phytochemicals, Montales et al (2015) reported that metformin and genistein targeted colon CSC spheroid formation and proliferation, and the combination increased the effectiveness of 5-FU [102]. Ning et al (2016) reported that both curcumin and metformin individually inhibited pancreatic CSC spheroids [103], the two compounds should be tested as a combination.…”