L group (P < 0.05); **Indicates significance of combination treatment as compared with UA alone (P < 0.05)explored the potential mechanism by which UA controls HCC cell growth. To this end, we showed that UA inhibited growth of HCC cells through p38 MAPKmediated induction expression of transcription factor purchase Doravirine IGFBP1 and FOXO3a in reciprocal interacted fashion. UA was found to inhibit growth in multiple HCC cell lines in the current study confirming the tumor suppressing properties of this agent in HCC cells. We did not observe the time-dependent effects of cell growth inhibition by UA and the reasons remained unclear. Whether longer time treatment (>72 h) showed significant changes needs to be determined. On the other hand, the possible desensitization of prolonged exposure of UA to the cells may also be responsible for this occurrence, which required to be confirmed. In our study, compared to the untreated control cells, there was actually 19 more G0/G1 phase cell arrest by UA treatment. We believed that this may explain the significant inhibition of cell growth by UA, while the possible UA-induced apoptosis of HCC cells may also occurred, which required tobe tested further. It was possible that the inhibition of proliferation could be in part a consequence of increased cell apoptosis. In addition, we demonstrated that UA inhibited growth of HCC cells through not only AMPK but also p38 MAPK indicating that activation of these two signaling pathways may be required for UA induced HCC growth inhibition [10]. These pathways reported to be associated with the anti-cancer effects were also found in other studies suggesting the common signaling network that mediated the anti-tumor responses of UA [10, 41?3]. Moreover, regulation of FOXO3a and IGFBP1 through p38 MAPK signaling pathway haven been shown in other studies [44, 45]. Of note, inactivation of p38 was also reported to be involved in the FOXO3a activation and expression [46]. Thus, the true role of AMPK and p38 MAPK signaling in modulating the FOXO3a and/or IGFBP1 expressions required to be determined. Moreover, our data supported crucial function of IGFBP1 in the current study. Increasing evidence suggested anYang et al. Journal of Experimental Clinical Cancer Research (2016) 35:Page 9 ofABDCEFig. 5 Silencing of FOXO3a overcame UA-induced cell growth inhibition and exogenous expressed FOXO3a enhanced UA-induced phosphorylation of p38 MAPK through IGFBP1. a, Bel-7402 and HepG2 cells were transfected with control and FOXO3a siRNAs for 24 h before exposing the cells to UA (25 M) for an additional 24 h. Afterwards, FOXO3a and IGFBP1 protein expressions were determined by Western blot. b, Bel-7402 and HepG2 cells were transfected with control PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/25768400 or FOXO3a siRNAs (up to 50 nM each) for 24 h prior to exposure of the cells to UA (25 M) for an additional 24 h. Afterwards, FOXO3a protein expression and cell viability were determined by Western blot and MTT assays. Insert represents the protein expression of FOXO3a. c-d, Bel-7402 and HepG2 cells were transfected with control and FOXO3a overexpression vectors for 24 h before exposing the cells to UA (25 M) for an additional 2 and 24 h, respectively. Afterwards, the protein levels of FOXO3a and p-p38 MAPK, and IGFBP1 protein expression were examined by Western blot. e, Bel-7402 and HepG2 cells silenced of IGFBP1 by siRNA previously were transfected with control and FOXO3a overexpression vector for 24 h before exposing the cells to UA (25 M) for an.