Korean mistletoe lectin promotes proliferation and invasion of trophoblast cells through regulation of Akt signaling

Alterations in IL-6/STAT3 Signaling by Korean Mistletoe Lectin Regulate the Self-Renewal Activity of Placenta-Derived Mesenchymal Stem Cells

Korean mistletoe (Viscum album L. var. coloratum) lectin (VCA) is known as an anticancer drug. However, it is not clear whether VCA affects the self-renewal activity of mesenchymal stem cells (MSCs). Therefore, the objectives of this study were to analyze the effect of VCA on the proliferation of MSCs and expression of stemness markers. We also evaluated the usefulness of placenta-derived MSCs (PD-MSCs) as a screening tool. VCA was stably administered to MSCs, and analyzed self-renewal activities. The effect of IL-6 signaling on MSC proliferation was explored by quantitative methylation-specific PCR (qMSP) and western blot analysis. Compared with the control condition, low concentrations of VCA (10 pg/mL) induced an increase in the self-renewal activity of MSCs. Interestingly, a low concentration of VCA promoted IL-6 signaling in PD-MSCs through altered IL-6/STAT3 gene methylation. Furthermore, inhibition of IL-6 expression in PD-MSCs using an anti-IL-6 antibody caused a decrease in their self-renewal activity through IL-6/STAT3 signaling by altering IL-6/STAT3 gene methylation. These findings provide helpful data for understanding the mechanism of MSC self-renewal via VCA and show that VCA may be useful as a functional natural product for developing efficient therapies using placenta-derived stem cells.

Transcriptomic and proteomic insight into the effects of a defined European mistletoe extract in Ewing sarcoma cells reveals cellular stress responses

BACKGROUND

The hydrophobic triterpenes, oleanolic and betulinic acid as well as the hydrophilic mistletoe lectins and viscotoxins possess anticancer properties. They do all occur in combination in European mistletoe (Viscum album L.). Commercial Viscum album L. extracts are aqueous, excluding the insoluble triterpenes. We have previously shown that mistletoe lectins and triterpene acids are effective against Ewing sarcoma in vitro, ex vivo and in vivo.

METHODS

We recreated a total mistletoe effect (viscumTT) by combining an aqueous extract (viscum) and a triterpene extract (TT) solubilised with cyclodextrins and analysed the effects of viscumTT and the single extracts on TC-71 Ewing sarcoma cells in vitro by transcriptomic and proteomic profiling.

RESULTS

Treatment with the extracts strongly impacted Ewing sarcoma cell gene and protein expression. Apoptosis-associated and stress-activated genes were upregulated, proteasomal protein abundance enhanced and ribosomal and spliceosomal proteins downregulated. The mechanism of action of viscum, TT and viscumTT in TC-71 and MHH-ES-1 cells suggests the involvement of the unfolded protein response. While viscum and viscumTT extract treatment indicate response to oxidative stress and activation of stress-mediated MAPK signalling, TT extract treatment suggests the involvement of TLR signalling and autophagy.

CONCLUSIONS

Since the combinatory extract viscumTT exerts highly effective pro-apoptotic effects on Ewing sarcoma cells in vitro, this phytopolychemotherapy could be a promising adjuvant therapeutic option for paediatric patients with Ewing sarcoma.

A combination of Korean mistletoe extract and resistance exercise retarded the decline in muscle mass and strength in the elderly: A randomized controlled trial

Given the increased concerns about the degenerative decline in the physical performance of the elderly, there is a need for developing effective strategies to suppress the age-related loss of skeletal muscle mass and functional capacity through a lifestyle intervention. This randomized controlled trial examined whether a combination of Korean mistletoe extract (KME) supplement and exercise affected muscle mass, muscle function, and targeted molecular expressions. Sixty-seven subjects aged 55-75years were assigned to placebo, low-dose (1g/d), or high-dose (2g/d) of KME for 12weeks. The body composition was significantly changed in the high-dose group during the intervention period as determined by skeletal muscle mass (P=0.040), fat free mass (P=0.042), soft lean mass (P=0.023), skeletal muscle index (P=0.041), fat-free mass index (P=0.030), percent body fat (P=0.044), and fat mass to lean mass ratio (P=0.030). Knee strength was measured by Cybex, demonstrating a significant effect in the KME groups compared to the placebo group (P=0.026 for peak torque and P=0.057 for set total work), which was more pronounced after adjusting for age, gender, protein, and energy intake (P=0.009 for peak torque and P=0.033 for set total work). The dynamic balance ability was remarkably improved in the high-dose group over a 12-week period as determined by Timed "Up and Go" (P=0.005 for fast walk test and P=0.024 for ordinary walk test). Consistent with these results, RT-PCR, multiplex analyses, and immunocytofluorescence staining revealed that a high-dose KME supplementation was effective for suppressing intracellular pathways related to muscle protein degradation, but stimulating those related to myogenesis. In particular, significant differences were found in atrogin-1 mRNA (P=0.002 at a single administration and P=0.001 at a 12-week administration), myogenin mRNA (P<0.0001 at a single administration and P=0.040 at a 12-week administration), and insulin growth factor 1 receptor phosphorylation (P=0.002 at a 12-week administration). These results suggest that KME supplementation together with resistance exercise may be useful in suppressing the age-related loss of muscle mass and strength in the elderly.

Anti-cancer effects of enteric-coated polymers containing mistletoe lectin in murine melanoma cells in vitro and in vivo

In this study, we evaluated the effects of Korean mistletoe (Viscum album L. var. coloratum) coated with a biodegradable polymer (Eudragit(®)) wall on the growth of mouse melanoma in vivo. Oral administration of 4% (430 mg/kg/day) enteric-coated mistletoe resulted in a significant reduction in tumor volume on day 14 compared to the negative control group in B16F10 melanoma-inoculated BDF1 mice. When we measured the survival rate, enteric-coated mistletoe-received mice had a higher survival rate after day 12. Also, we investigated the mechanism involving the cancer cell growth inhibition when melanoma cells were treated with Korean mistletoe lectin (Viscum album L. var. coloratum agglutinin, VCA) and its extract in vitro. As a result, a significant G0/G1 arrest was observed in both B16BL6 and B16F10 melanoma cells with VCA or mistletoe extract. In addition, VCA or mistletoe extract induced an increase in both early and late apoptosis in cells. When we studied the molecular mechanism, our results showed that VCA and mistletoe extract can increase activated multiple caspases (caspase-1, 3, 4, 5, 6, 7, 8, and 9), dose-dependently. We also found out that VCA and mistletoe treatment causes a significant decrease in the expression of procaspase-3 and 8.

Uterine NDRG2 expression is increased at implantation sites during early pregnancy in mice, and its down-regulation inhibits decidualization of mouse endometrial stromal cells

BACKGROUND

N-myc down-regulated gene 2 (NDRG2) is a tumor suppressor involved in cell proliferation and differentiation. The aim of this study was to determine the uterine expression pattern of this gene during early pregnancy in mice.

METHODS

Uterine NDRG2 mRNA and protein expression levels were determined by RT-PCR and Western blot analyses, respectively, during the peri-implantation period in mice. Immunohistochemical (IHC) analysis was performed to examine the spatial localization of NDRG2 expression in mouse uterine tissues. The in vitro decidualization model of mouse endometrial stromal cells (ESCs) was used to evaluate decidualization of ESCs following NDRG2 knock down by small interfering RNA (siRNA). Statistical significance was analyzed by one-way ANOVA using SPSS 19.0 software.

RESULTS

Uterine NDRG2 gene expression was significantly up-regulated and was predominantly localized to the secondary decidual zone on days 5 and 8 of pregnancy in mice. Its increased expression was associated with artificial decidualization as well as the activation of delayed implantation. Furthermore, uterine NDRG2 expression was induced by estrogen and progesterone treatments. The in vitro decidualization of mouse ESCs was accompanied by up-regulation of NDRG2 expression, and knock down of its expression in these cells by siRNA inhibited the decidualization process.

CONCLUSIONS

These results suggest that NDRG2 might play an important role in the process of decidualization during early pregnancy.

Protein Fractions from Korean Mistletoe (Viscum Album coloratum) Extract Induce Insulin Secretion from Pancreatic Beta Cells

Mistletoe (Viscum Album coloratum) has been known as a medicinal plant in European and Asian countries. Recent data show that biological activity of mistletoe alleviates hypertension, heart disease, renal failure, and cancer development. In this study, we report the antidiabetic effect of Korean mistletoe extract (KME). KME treatments enhanced the insulin secretion from the pancreatic β-cell without any effects of cytotoxicity. PDX-1 and beta2/neuroD known as transcription factors that regulate the expression of insulin gene were upregulated by treatment of the KME protein fractions isolated by ion-exchange chromatography after ammonium sulfate precipitation. Furthermore, these KME protein fractions significantly lowered the blood glucose level and the volume of drinking water in alloxan induced hyperglycemic mice. Taken together with the findings, it provides new insight that KME might be served as a useful source for the development of medicinal reagent to reduce blood glucose level of type I diabetic patients.