As a plant medicine, Oxalidaceae has been used to treat various diseases in Korea. However, there is little data on the anti-cancer efficacy of Oxalidaceae, particularly O. obtriangulata. This study aimed to investigate the anti-cancer effect of O. obtriangulata methanol extract (OOE) and its regulatory actions on pancreatic carcinoma. OOE showed anti-proliferative effects and induced cell death in the colony formation and cell viability assays, respectively. The Fluorescence-activated cell sorting (FACS) data confirmed that OOE significantly induced cell cycle accumulation at the G2/M phase and apoptotic effects. Additionally, OOE inhibited the activated ERK (extracellular-signal-regulated kinase)/Src (Proto-oncogene tyrosine-protein kinase Src)/STAT3 (signal transducers and activators of transcription 3) pathways including nuclear translocation of STAT3. Furthermore, suppression of Ki67, PARP(Poly ADP-ribose polymerase), caspase-3, P27(Cyclin-dependent kinase inhibitor 1B), and c-Myc as well as the STAT3 target genes CDK(cyclin-dependent kinase)1, CDK2, Cyclin B1, VEGF-1(vascular endothelial growth factor-1), MMP-9(Matrix metallopeptidase 9), and Survivin by OOE was observed in BxPC3. We speculate that these molecular actions might support an anti-cancer effect of OOE. In this study, we demonstrated that OOE may be a promising anti-cancer material and may serve as a natural therapy and alternative remedy for pancreatic cancer treatment.

Timosaponin A3 (TA3) was demonstrated as a potent anticancer chemical by several studies. Although the effects of inhibiting growth, metastasis, and angiogenesis in various cancer cells were demonstrated through multiple mechanisms, the pharmacological mechanism of TA3 shown in pancreatic cancer (PC) is insufficient compared to other cancers. In this study, we aimed to explore the key molecular mechanisms underlying the growth inhibitory effects of TA3 using PC cells and a xenograft model. First, from the microarray results, we found that TA3 regulated INSIG-1 and HMGCR in BxPC-3 cells. Furthermore, we showed that inhibition of sterol regulatory element-binding protein-1 (SREBP-1) by TA3 reduced the fatty acid synthases FASN and ACC, thereby controlling the growth of BxPC-3 cells. We also tried to find mechanisms involved with SREBP-1, such as Akt, Gsk3β, mTOR, and AMPK, but these were not related to SREBP-1 inhibition by TA3. In the BxPC-3 xenograft model, the TA3 group had more reduced tumor formation and lower toxicity than the gemcitabine group. Interestingly, the level of the fatty acid metabolites palmitate and stearate were significantly reduced in the tumor tissue in the TA3 group. Overall, our study demonstrated that SREBP-1 was a key transcription factor involved in pancreatic cancer growth and it remained a precursor form due to TA3, reducing the adipogenesis and growth in BxPC-3 cells. Our results improve our understanding of novel mechanisms of TA3 for the regulation of lipogenesis and provide a new approach to the prevention and treatment of PC.

A correlation between gastrointestinal (GI) inflammation and gut hormones has reported that inflammatory stimuli including bacterial endotoxins, lipopolysaccharides (LPS), TNFα, IL-1β, and IL-6 induces high levels of incretin hormone leading to glucose dysregulation. Although incretin hormones are immediately secreted in response to environmental stimuli, such as nutrients, cytokines, and LPS, but studies of glucose-induced incretin secretion in an inflamed state are limited. We hypothesized that GI inflammatory conditions induce over-stimulated incretin secretion via an increase of glucose-sensing receptors. To confirm our hypothesis, we observed the alteration of glucose-induced incretin secretion and glucose-sensing receptors in a GI inflammatory mouse model, and we treated a conditioned media (Mϕ 30%) containing inflammatory cytokines in intestinal epithelium cells and enteroendocrine L-like NCI-H716 cells. In GI-inflamed mice, we observed that over-stimulated incretin secretion and insulin release in response to glucose and sodium glucose cotransporter (Sglt1) was increased. Incubation with Mϕ 30% increases Sglt1 and induces glucose-induced GLP-1 secretion with increasing intracellular calcium influx. Phloridzin, an sglt1 inhibitor, inhibits glucose-induced GLP-1 secretion, ERK activation, and calcium influx. These findings suggest that the abnormalities of incretin secretion leading to metabolic disturbances in GI inflammatory disease by an increase of Sglt1.