Nanog is a promising chemoresistant stemness marker and therapeutic target by iron chelators for esophageal cancer.

Esophageal cancer is a disease showing poor prognosis. Although combination chemotherapy using cisplatin (CDDP) and 5-fluorouracil is standard for unresectable esophageal cancer, the response rate is 35%. Cancer stem cells (CSCs) and inflammation are reportedly responsible for the poor prognosis of esophageal cancer. However, comprehensive analyses have not been conducted and proposals for progress remain lacking. Iron is known to be a key factor in the stemness of CSCs. Our study focused on the therapeutic potential of iron control using iron chelators for CSCs in esophageal cancer. Among 134 immunohistochemically analyzed cases, Nanog expression was high in 98 cases and low in 36 cases. High Nanog expression correlated with low overall and disease-free survivals. The iron chelators deferasirox (DFX) and SP10 suppressed the proliferation and expression of stemness markers in TE8 and OE33 cells. DFX and SP10 did not induce compensatory interleukin (IL)-6 secretion, although CDDP did result in high induction. Moreover, BBI608 and SSZ, as other CSC-targeting drugs, could not suppress the expression of stemness markers. Overall, Nanog expression appears related to poor prognosis in esophageal cancer patients, and inhibition of stemness and compensatory IL-6 secretion by iron chelators may offer a novel therapeutic strategy for esophageal cancer.

Zinc oxide nanoparticles promote the aging process in a size-dependent manner.

Zinc oxide (ZnO) nanoparticles (NPs) are generally utilized in cosmetic goods, sheds, biosensors, and delivery of drug. As in vitro ideal systems, mesenchymal stem cells (MSCs) are used to test acute toxicity. In the present study, size-dependent cytotoxicity effects of ZnO NPs on MSCs were assessed. Bone marrow and adipose MSCs were treated with ZnO NPs with average sizes of 10-30 and 35-45 nm. The 5 and 10 µg/ml concentrations of ZnO NP were found to be the safe concentrations for the NP sizes of 10-30 and 35-45 nm, respectively. Cell-cycle analysis indicated that the small size of ZnO NPs has more negative effects on the process of cell entry to DNA synthesis when compared to the larger size. The results of the ß-galactosidase test showed the promotion of the aging process in the cells treated with the smaller size of ZnO NPs. Both sizes of the NP were found to upregulate the aging-related genes NF-kB and p53 and downregulate the anti-aging gene Nanog. To sum up, the smaller size of ZnO NPs can enhance the aging process in the cells.

Inhibition of DNA Methyltransferase by RG108 Promotes Pluripotency-Related Character of Porcine Bone Marrow Mesenchymal Stem Cells.

Mesenchymal stem/stromal cells (MSCs) have been identified in almost all adult human tissues and been used in numerous clinical trials for a variety of diseases. Studies have shown that MSCs would undergo cellular senescence when cultured over a long term, which is brought on by increased epigenetic modifications, including DNA methylation. However, the mechanism of MSCs senescence is not well studied. In this study, the effects of RG108, a DNA methyltransferase inhibitor (DNMTi), on senescence, apoptosis, and pluripotency gene expressions in porcine bone marrow (pBM)-MSCs were investigated. First, we determined the optimized dose and time of RG108 treatment in pBM-MSCs to be 10 µM for 48 hours, respectively. Under these conditions, the pluripotency genes (NANOG, POU5F1), the anti-senescence genes (TERT, bFGF), and the anti-apoptosis gene (BCL2) were increased, whereas the apoptotic gene (BAX) was decreased. RG108 protected against apoptosis when pBM-MSC induces apoptosis with H2O2 for 1.5 hours. We also found that RG108 significantly induced the expression of NANOG and POU5F1 by decreasing DNA methylation in gene promoter regions. These results indicate that an optimized dose of RG108 may promote the pluripotency-related character of pBM-MSCs through improving cellular anti-senescence, anti-apoptosis, and pluripotency, which provide a better cell origin for stem cell therapy.

Targeting Mcl-1 inhibits survival and self-renewal of hepatocellular cancer stem-like cells.

Myeloid cell leukemia-1 (Mcl-1) is highly expressed in tumor tissues and cells of hepatocellular carcinoma (HCC), yet the role of Mcl-1 in cancer stem-like cells (CSLCs) remains largely unclear. Herein, we showed that knockdown of Mcl-1 significantly inhibited HCC cells to form spheres under ultra-low attachment condition in serum-free medium, and also attenuated clone formation. Inhibition of Mcl-1 by specific inhibitors S63845 or A-1210477 hindered secondary sphere formation, triggered apoptosis signaling and reduced the level of stem cell transcription factor Nanog, Sox2 and KLF4 in HCC spheroids cells. This study suggests that Mcl-1 is an essential factor for the survival and self-renewal of HCC CSLCs.

Apigenin inhibited hypoxia induced stem cell marker expression in a head and neck squamous cell carcinoma cell line.

OBJECTIVE: Cancer stem cells contribute to tumor recurrence, and a hypoxic environment is critical for maintaining cancer stem cells. Apigenin is a natural product with anticancer activity. However, the effect of apigenin on cancer stem cells remains unclear. Our aim was to investigate the effect of apigenin on cancer stem cell marker expression in head and neck squamous cell carcinoma cells under hypoxia. DESIGN: We used three head and neck squamous cell carcinoma cell lines; HN-8, HN-30, and HSC-3. The mRNA expression of cancer stem cell markers was determined by semiquantitative RT-PCR and Real-time PCR. The cytotoxic effect of apigenin was determined by MTT colorimetric assay. Flow cytometry was used to reveal the number of cells expressing cancer stem cell surface markers. RESULTS: HN-30 cells, a cancer cell line from the pharynx, showed the greatest response to hypoxia by increasing their expression of CD44, CD105, NANOG, OCT-4, REX-1, and VEGF. Apigenin significantly decreased HN-30 cell viability in dose- and time-dependent manners. In addition, 40µM apigenin significantly down-regulated the mRNA expression of CD44, NANOG, and CD105. Consistent with these results, the hypoxia-induced increase in CD44+ cells, CD105+ cells, and STRO-1+ cells was significantly abolished by apigenin. CONCLUSION: Apigenin suppresses cancer stem cell marker expression and the number of cells expressing cell surface markers under hypoxia.