Gene Expression and DNA Methylation Profiling Suggest Potential Biomarkers for Azacitidine Resistance in Myelodysplastic Syndrome.

Myelodysplastic syndrome/neoplasm (MDS) comprises a group of heterogeneous hematopoietic disorders that present with genetic mutations and/or cytogenetic changes and, in the advanced stage, exhibit wide-ranging gene hypermethylation. Patients with higher-risk MDS are typically treated with repeated cycles of hypomethylating agents, such as azacitidine. However, some patients fail to respond to this therapy, and fewer than 50% show hematologic improvement. In this context, we focused on the potential use of epigenetic data in clinical management to aid in diagnostic and therapeutic decision-making. First, we used the F-36P MDS cell line to establish an azacitidine-resistant F-36P cell line. We performed expression profiling of azacitidine-resistant and parental F-36P cells and used biological and bioinformatics approaches to analyze candidate azacitidine-resistance-related genes and pathways. Eighty candidate genes were identified and found to encode proteins previously linked to cancer, chronic myeloid leukemia, and transcriptional misregulation in cancer. Interestingly, 24 of the candidate genes had promoter methylation patterns that were inversely correlated with azacitidine resistance, suggesting that DNA methylation status may contribute to azacitidine resistance. In particular, the DNA methylation status and/or mRNA expression levels of the four genes (AMER1, HSPA2, NCX1, and TNFRSF10C) may contribute to the clinical effects of azacitidine in MDS. Our study provides information on azacitidine resistance diagnostic genes in MDS patients, which can be of great help in monitoring the effectiveness of treatment in progressing azacitidine treatment for newly diagnosed MDS patients.

Anti-Tumor Efficacy of Oleuropein-Loaded ZnO/Au Mesoporous Silica Nanoparticle in 5-FU-Resistant Colorectal Cancer Cells.

Purpose: 5-fluorouracil (5-FU) is a first-line chemotherapeutic agent used to treat colorectal cancer (CRC). However, 5-FU induces drug resistance and activation of cancer stem cells (CSCs). In the present study, we designed a novel biocompatible nanomedicine system with high efficacy and biocompatibility by synthesizing mesoporous silica nanoparticle (MSN)-structured ZnO and gold ions. Oleuropein (OLP) is a phenolic compound derived from olive leaves that exerts anti-cancer effects. Therefore, we synthesized OLP-loaded ZnO/Au MSNs (ZnO/Au/OLP MSNs) and examined their anti-cancer effects on 5-FU-resistant CRC cells. Methods: ZnO/Au MSNs were synthesized and functionalized, and their physical and chemical compositions were characterized using UV-visible spectroscopy, dynamic light scattering, and transmission electron microscopy (TEM). Their effects were assessed in terms of cellular proliferation capacity, migration and invasion ability, colony-forming ability, spheroid-forming ability, reactive oxygen species (ROS) production, and mitochondrial membrane depolarization. Results: ZnO/Au MSNs were mostly composed of various ions containing ZnO and gold ions, had a spheroid phenotype, and exhibited no cytotoxicity. ZnO/Au/OLP MSNs reduced cell viability and CSC formation and induced apoptosis of 5-FU-resistant CRC cells via necrosis via ROS accumulation and DNA fragmentation. Conclusion: ZnO/Au/OLP MSNs exhibited anti-cancer activity by upregulating necrosis. These results revealed that ZnO/Au/OLP MSNs are a novel drug delivery system for 5-FU CRC therapy.

Analysis of Under-Diagnosed Malignancy during Fine Needle Aspiration Cytology of Lymphadenopathies.

Fine needle aspiration cytology (FNAC) is a useful tool in the evaluation of lymphadenopathy. It is a safe and minimally invasive procedure that provides preoperative details for subsequent treatment. It can also diagnose the majority of malignant tumors. However, there are some instances where the diagnosis of tumors remains obscure. To address this, we re-analyzed the misinterpreted patients' samples using mRNA sequencing technology and then identified the characteristics of non-Hodgkin's lymphoma that tend to be under-diagnosed. To decipher the involved genes and pathways, we used bioinformatic and biological analysis approaches, identifying the response to oxygen species, inositol phosphate metabolic processes, and peroxisome and PPAR pathways as possibly being involved with this type of tumor. Notably, these analyses identified FOS, ENDOG, and PRKAR2B as hub genes. cBioPortal, a multidimensional cancer genomics database, also confirmed that these genes were associated with lymphoma patients. These results thus point to candidate genes that could be used as biomarkers to minimize the false-negative rate of FNAC diagnosis. We are currently pursuing the development of a gene chip to improve the diagnosis of lymphadenopathy patients with the ultimate goal of improving their prognosis.

Cyclin D1 promotes radioresistance through regulation of RAD51 in melanoma.

Melanoma is a notoriously radioresistant type of skin cancer. Elucidation of the specific mechanisms underlying radioresistance is necessary to improve the clinical efficacy of radiation therapy. To identify the key factors contributing to radioresistance, five melanoma cell lines were selected for study and genes that were upregulated in relatively radioresistant melanomas compared with radiosensitive melanoma cells determined via RNA sequencing technology. In particular, we focused on cyclin D1 (CCND1), a well known cell cycle regulatory molecule. In radiosensitive melanoma, overexpression of cyclin D1 reduced apoptosis. In radioresistant melanoma cell lines, suppression of cyclin D1 with a specific inhibitor or siRNA increased apoptosis and decreased cell proliferation in 2D and 3D spheroid cultures. In addition, we observed increased expression of γ-H2AX, a molecular marker of DNA damage, even at a later time after γ-irradiation, under conditions of inhibition of cyclin D1, with a response pattern similar to that of radiosensitive SK-Mel5. In the same context, expression and nuclear foci formation of RAD51, a key enzyme for homologous recombination (HR), were reduced upon inhibition of cyclin D1. Downregulation of RAD51 also reduced cell survival to irradiation. Overall, suppression of cyclin D1 expression or function led to reduced radiation-induced DNA damage response (DDR) and triggered cell death. Our collective findings indicate that the presence of increased cyclin D1 potentially contributes to the development of radioresistance through effects on RAD51 in melanoma and could therefore serve as a therapeutic target for improving the efficacy of radiation therapy.

Utility and Limitations of Fine-Needle Aspiration Cytology in the Diagnosis of Lymphadenopathy.

BACKGROUND: Fine needle aspiration cytology (FNAC) is a valuable tool for evaluating lymphadenopathy. The purpose of this study was to assess the reliability and effectiveness of FNAC in the diagnosis of lymphadenopathy. METHODS: Cytological characteristics were evaluated in 432 patients who underwent lymph node FNAC and follow-up biopsy at the Korea Cancer Center Hospital from January 2015 to December 2019. RESULTS: Fifteen (3.5%) of the four hundred and thirty-two patients were diagnosed as inadequate by FNAC, with five (33.3%) of these diagnosed as metastatic carcinoma on histological examination. Of the 432 patients, 155 (35.9%) were diagnosed as benign by FNAC, with seven (4.5%) of these diagnosed histologically as metastatic carcinoma. A review of the FNAC slides, however, showed no evidence of cancer cells, suggesting that the negative results may have been due to FNAC sampling errors. An additional five samples regarded as benign on FNAC were diagnosed as non-Hodgkin lymphoma (NHL) by histological examination. Of the 432 patients, 223 (51.6%) were cytologically diagnosed as malignant, with 20 (9.0%) of these diagnosed as tissue insufficient for diagnosis (TIFD) or benign on histological examination. A review of the FNAC slides of these 20 patients, however, showed that 17 (85.0%) were positive for malignant cells. The sensitivity, specificity, positive predictive value (PPV), negative predictive values (NPV), and accuracy of FNAC were 97.8%, 97.5%, 98.7%, 96.0%, and 97.7%, respectively. CONCLUSIONS: Preoperative FNAC was safe, practical, and effective in the early diagnosis of lymphadenopathy. This method, however, had limitations in some diagnoses, suggesting that additional attempts may be required according to the clinical situation.

IGFL2-AS1, a Long Non-Coding RNA, Is Associated with Radioresistance in Colorectal Cancer.

Precise prediction of radioresistance is an important factor in the treatment of colorectal cancer (CRC). To discover genes that regulate the radioresistance of CRCs, we analyzed an RNA sequencing dataset of patient-originated samples. Among various candidates, IGFL2-AS1, a long non-coding RNA (lncRNA), exhibited an expression pattern that was well correlated with radioresistance. IGFL2-AS1 is known to be highly expressed in various cancers and functions as a competing endogenous RNA. To further investigate the role of IGFL2-AS1 in radioresistance, which has not yet been studied, we assessed the amount of IGFL2-AS1 transcripts in CRC cell lines with varying degrees of radioresistance. This analysis showed that the more radioresistant the cell line, the higher the level of IGFL2-AS1 transcripts-a similar trend was observed in CRC samples. To directly assess the relationship between IGFL2-AS1 and radioresistance, we generated a CRC cell line stably expressing a small hairpin RNA (shRNA) targeting IGFL2-AS1. shRNA-mediated knockdown of IGFL2-AS1 decreased radioresistance and cell migration in vitro, establishing a functional role for IGFL2-AS1 in radioresistance. We also showed that downstream effectors of the AKT pathway played crucial roles. These data suggest that IGFL2-AS1 contributes to the acquisition of radioresistance by regulating the AKT pathway.

Horticoccus luteus gen. nov., sp. nov., A Novel Member of the Phylum Verrucomicrobia Isolated from a Dichlorodiphenyltrichloroethane (DDT)-Contaminated Orchard Soil.

Strain KSB-15 T was isolated from an orchard soil that had been contaminated with the insecticide dichlorodiphenyltrichloroethane for about 60 years. The 16S rRNA gene sequence of this strain showed the highest sequence similarities with those of Oleiharenicola alkalitolerans NVTT (95.3%), Opitutus terrae PB90-1 T (94.8%), and Oleiharenicola lentus TWA-58 T (94.7%) among type strains, which are members of the family Opitutaceae within the phylum Verrucomicrobia. Strain KSB-15 T was an obligate aerobe, Gram-negative, non-motile, coccoid or short rod with the cellular dimensions of 0.37-0.62 µm width and 0.43-0.72 µm length. The strain grew at temperatures between 15-37 °C (optimum, 25 °C), at a pH range of 5.0-11.0 (optimum, pH 6.0), and at a NaCl concentration of 0-3% (w/v) (optimum, 0%). It contained menaquinone-7 (MK-7) as the major isoprenoid quinone (94.1%), and iso-C15:0 (34.9%) and anteiso-C15:0 (29.0%) as the two major fatty acids. The genome of strain KSB-15 T was composed of one chromosome with a total size of 4,320,198 bp, a G + C content of 64.3%, 3,393 coding genes (CDS), 14 pseudogenes, and 52 RNA genes. The OrthoANIu values, In silico DDH values and average amino acid identities between strain KSB-15 T and the members of the family Opitutaceae were 71.6 ~ 73.0%, 19.0 ~ 19.9%, and 55.9 ~ 62.0%, respectively. On the basis of our polyphasic taxonomic study, we conclude that strain KSB-15 T should be classified as a novel genus of the family Opitutaceae, for which the name Horticcoccus luteus gen. nov., sp. nov. is proposed.The type strain is KSB-15 T (= KACC 22271 T = DSM 113638 T).

Promyelocytic Leukemia Proteins Regulate Fanconi Anemia Gene Expression.

Promyelocytic leukemia (PML) protein is the core component of subnuclear structures called PML nuclear bodies that are known to play important roles in cell survival, DNA damage responses, and DNA repair. Fanconi anemia (FA) proteins are required for repairing interstrand DNA crosslinks (ICLs). Here we report a novel role of PML proteins, regulating the ICL repair pathway. We found that depletion of the PML protein led to the significant reduction of damage-induced FANCD2 mono-ubiquitination and FANCD2 foci formation. Consistently, the cells treated with siRNA against PML showed enhanced sensitivity to a crosslinking agent, mitomycin C. Further studies showed that depletion of PML reduced the protein expression of FANCA, FANCG, and FANCD2 via reduced transcriptional activity. Interestingly, we observed that damage-induced CHK1 phosphorylation was severely impaired in cells with depleted PML, and we demonstrated that CHK1 regulates FANCA, FANCG, and FANCD2 transcription. Finally, we showed that inhibition of CHK1 phosphorylation further sensitized cancer cells to mitomycin C. Taken together, these findings suggest that the PML is critical for damage-induced CHK1 phosphorylation, which is important for FA gene expression and for repairing ICLs.

Injectable in situ forming hydrogel gene depot to improve the therapeutic effect of STAT3 shRNA.

Down-regulation of the signal transducer and activity of transcription 3 (Stat3) plays a crucial role in suppression of many solid tumors. Intratumoral injection of a gene carrier applying Stat3-small hairpin RNA (St3-shRNA) is a potential therapeutic strategy. To our knowledge, this is the first report of the intratumoral injection of St3-shRNA using a gene carrier. We herein designed biodegradable (methoxy)polyethylene glycol-b-(polycaprolactone-ran-polylactide) copolymer (MP) derivatized with a spermine group with cationic properties at the pendant position of the MP chain (MP-NH2). The designed MP-NH2 can act as a gene carrier of St3-shRNA by forming an electrostatic complex with cationic spermine. This can increase the stability of the complexes because of protection of PEG in biologic environments and can exhibit a sol-gel phase transition around body temperature for the formation of intratumorally injected MP-NH2 hydrogel depot for St3-shRNA. MP-NH2 was observed to completely condense with St3-shRNA to form St3-shRNA/MP-NH2 complexes. These complexes were protected for a relatively long time (≥72 h) from external biologic molecules of the serum, DNase, and heparin. St3-shRNA/MP-NH2 complexes in in vitro tumor cell experiments can enhance transfection of St3-shRNA, correspondingly enhance Stat3 knockdown efficiency, and inhibit tumor cell growth. St3-shRNA/MP-NH2 complexes and St3-shRNA/MP-NH2 complex-loaded hydrogel were intratumorally injected into the tumor as new efficient delivery carriers and depots of St3-shRNA. The intratumoral injection of St3-shRNA/MP-NH2 complexes and St3-shRNA/MP-NH2 complex-loaded hydrogel showed effective anti-tumor effect for an extended period of time due to the effect of Stat3 knockdown. Collectively, the development of MP-NH2 as a carrier and depot of St3-shRNA provides a new strategy for St3-shRNA therapy through intratumoral injection with high efficacy and minimal adverse effects.

Involvement of Klotho, TNF­α and ADAMs in radiation­induced senescence of renal epithelial cells.

While radiation nephropathy is a major problem associated with radiotherapy, the exact mechanisms underlying its pathogenesis and the mediators involved in kidney deterioration remain to be elucidated. In view of the finding that senescence is typically increased post­irradiation, the present study examined whether ionizing radiation may cause kidney injury by enhancing premature senescence. The present study explored the relevance of the aging suppressor, Klotho, which has anti­aging activity and is highly expressed in murine renal cells/kidney tissues, under irradiation conditions. Firstly, the effects of radiation on mouse inner medullary collecting duct­3 (mIMCD­3) cells and kidney tissues of mice were assessed. Subsequently, the mRNA expression levels of Klotho, TNF­α and ADAM metallopeptidase domain (ADAM)9/10/17 were analyzed by reverse transcription­quantitative PCR following exposure to radiation. In addition, the levels of these proteins were measured by western blotting or ELISA. The results revealed that irradiation of mIMCD­3 cells clearly triggered cellular senescence. Notably, Klotho gene expression was considerably decreased in radiation­exposed mIMCD­3 cells and in the kidney tissues of irradiated BALB/c mice, and the corresponding translated protein was consistently expressed following radiation exposure. Moreover, expression of TNF­α, a negative regulator of Klotho, was significantly increased, whereas ADAM9/10/17, an ectodomain shedding enzyme of Klotho, was decreased in irradiated mIMCD­3 cells and in the kidney tissues of BALB/c mice. Collectively, these data suggested that TNF­α­mediated inhibition of Klotho expression and blockage of soluble Klotho formation via decreased ADAM expression following irradiation may contribute to the development of renal dysfunction through acceleration of radiation­induced cellular senescence.

Pharmacological inhibition of mTOR attenuates replicative cell senescence and improves cellular function via regulating the STAT3-PIM1 axis in human cardiac progenitor cells.

The mammalian target of rapamycin (mTOR) signaling pathway efficiently regulates the energy state of cells and maintains tissue homeostasis. Dysregulation of the mTOR pathway has been implicated in several human diseases. Rapamycin is a specific inhibitor of mTOR and pharmacological inhibition of mTOR with rapamycin promote cardiac cell generation from the differentiation of mouse and human embryonic stem cells. These studies strongly implicate a role of sustained mTOR activity in the differentiating functions of embryonic stem cells; however, they do not directly address the required effect for sustained mTOR activity in human cardiac progenitor cells. In the present study, we evaluated the effect of mTOR inhibition by rapamycin on the cellular function of human cardiac progenitor cells and discovered that treatment with rapamycin markedly attenuated replicative cell senescence in human cardiac progenitor cells (hCPCs) and promoted their cellular functions. Furthermore, rapamycin not only inhibited mTOR signaling but also influenced signaling pathways, including STAT3 and PIM1, in hCPCs. Therefore, these data reveal a crucial function for rapamycin in senescent hCPCs and provide clinical strategies based on chronic mTOR activity.

Engineered M13 Peptide Carrier Promotes Angiogenic Potential of Patient-Derived Human Cardiac Progenitor Cells and In Vivo Engraftment.

BACKGROUND: Despite promising advances in stem cell-based therapy, the treatment of ischemic cardiovascular diseases remains a big challenge due to both the insufficient in vivo viability of transplanted cells and poor angiogenic potential of stem cells. The goal of this study was to develop therapeutic human cardiac progenitor cells (hCPCs) for ischemic cardiovascular diseases with a novel M13 peptide carrier. METHOD: In this study, an engineered M13 peptide carrier was successfully generated using a QuikChange Kit. The cellular function of M13 peptide carrier-treated hCPCs was assessed using a tube formation assay and scratch wound healing assay. The in vivo engraftment and cell survival bioactivities of transplanted cells were demonstrated by immunohistochemistry after hCPC transplantation into a myocardial infarction animal model. RESULTS: The engineered M13RGD+SDKP peptide carrier, which expressed RGD peptide on PIII site and SDKP peptide on PVIII site, did not affect morphologic change and proliferation ability in hCPCs. In contrast, hCPCs treated with M13RGD+SDKP showed enhanced angiogenic capacity, including tube formation and migration capacity. Moreover, transplanted hCPCs with M13RGD+SDKP were engrafted into the ischemic region and promoted in vivo cell survival. CONCLUSION: Our present data provides a promising protocol for CPC-based cell therapy via short-term cell priming of hCPCs with engineered M13RGD+SDKP before cell transplantation for treatment of cardiovascular disease.

Mechanisms of Energy Metabolism in Skeletal Muscle Mitochondria Following Radiation Exposure.

An understanding of cellular processes that determine the response to ionizing radiation exposure is essential for improving radiotherapy and assessing risks to human health after accidental radiation exposure. Radiation exposure leads to many biological effects, but the mechanisms underlying the metabolic effects of radiation are not well known. Here, we investigated the effects of radiation exposure on the metabolic rate and mitochondrial bioenergetics in skeletal muscle. We show that ionizing radiation increased mitochondrial protein and mass and enhanced proton leak and mitochondrial maximal respiratory capacity, causing an increase in the fraction of mitochondrial respiration devoted to uncoupling reactions. Thus, mice and cells treated with radiation became energetically efficient and displayed increased fatty acid and amino acid oxidation metabolism through the citric acid cycle. Finally, we demonstrate that radiation-induced alterations in mitochondrial energy metabolism involved adenosine monophosphate-activated kinase signaling in skeletal muscle. Together, these results demonstrate that alterations in mitochondrial mass and function are important adaptive responses of skeletal muscle to radiation.

Enzyme-Aided Extraction of Fucoidan by AMG Augments the Functionality of EPCs through Regulation of the AKT/Rheb Signaling Pathway.

The purpose of the present study is to improve the endothelial progenitor cells (EPC) activation, proliferation, and angiogenesis using enzyme-aided extraction of fucoidan by amyloglucosidase (EAEF-AMG). Enzyme-aided extraction of fucoidan by AMG (EAEF-AMG) significantly increased EPC proliferation by reducing the reactive oxygen species (ROS) and decreasing apoptosis. Notably, EAEF-AMG treated EPCs repressed the colocalization of TSC2/LAMP1 and promoted perinuclear localization of mTOR/LAMP1 and mTOR/Rheb. Moreover, EAEF-AMG enhanced EPC functionalities, including tube formation, cell migration, and wound healing via regulation of AKT/Rheb signaling. Our data provided cell priming protocols to enhance therapeutic applications of EPCs using bioactive compounds for the treatment of CVD.

AGR2 is a target of canonical Wnt/ß-catenin signaling and is important for stemness maintenance in colorectal cancer stem cells.

Colorectal cancer is one of the leading causes of cancer-related deaths. Due to relapse after current therapy regimens, cancer stem cells (CSCs) are being studied to target this small tumor-initiating population. Anterior gradient 2 (AGR2), a disulfide isomerase protein, is a well-known pro-oncogenic/metastatic oncogene overexpressed in various tumor tissues, including colon cancer. We found that AGR2 was a novel stem cell marker that was regulated by the canonical Wnt/ß-catenin pathway in colon CSCs. AGR2 was highly co-expressed with surface stem cell markers in spheroidal culture. Silencing of AGR2 resulted in decreased sphere-forming ability and down-regulated expression of stem cell markers, whereas the opposite effects were seen with AGR2 overexpression. Moreover, patients with high ß-catenin and AGR2 expression showed lower overall survival than those with low expression. In conclusion, our study describes a novel role for AGR2 as a stem cell marker that is highly regulated by canonical Wnt/ß-catenin signaling in colorectal cancer.

Basic helix-loop-helix transcription factor Twist1 is a novel regulator of anterior gradient protein 2 homolog (AGR2) in breast cancer.

Anterior gradient protein 2 homolog (AGR2) belongs to the disulfide isomerase family of endoplasmic reticulum proteins. Itis overexpressed in several types of solid tumors, including tumors of the prostate, lung, and pancreas. However, the role of AGR2 in breast cancer and the regulatory mechanisms underlying AGR2 protein expressionare not fullyunderstood. We demonstrated that AGR2 levels are increased under hypoxic conditions and in breast cancer tumors. Mechanistically, Twist1 binds to, and activates the AGR2 promoter via an E-box sequence. Under hypoxic conditions, the increased expression of ARG2 is attenuated when Twist1 levels are reduced by shRNA. Conversely, Twist1 overexpression fully reverses decreased AGR2 levels upon HIF-1α knockdown. Notably, AGR2 is required for Twist1-induced proliferation, migration, and invasion of breast cancer cells. Collectively, these findings extend our understanding of AGR2 regulation in breast cancer and may contribute to development of Twist1-AGR2 targeting therapeutics for breast cancer.

Therapeutic Cell Protective Role of Histochrome under Oxidative Stress in Human Cardiac Progenitor Cells.

Cardiac progenitor cells (CPCs) are resident stem cells present in a small portion of ischemic hearts and function in repairing the damaged heart tissue. Intense oxidative stress impairs cell metabolism thereby decreasing cell viability. Protecting CPCs from undergoing cellular apoptosis during oxidative stress is crucial in optimizing CPC-based therapy. Histochrome (sodium salt of echinochrome A-a common sea urchin pigment) is an antioxidant drug that has been clinically used as a pharmacologic agent for ischemia/reperfusion injury in Russia. However, the mechanistic effect of histochrome on CPCs has never been reported. We investigated the protective effect of histochrome pretreatment on human CPCs (hCPCs) against hydrogen peroxide (H2O2)-induced oxidative stress. Annexin V/7-aminoactinomycin D (7-AAD) assay revealed that histochrome-treated CPCs showed significant protective effects against H2O2-induced cell death. The anti-apoptotic proteins B-cell lymphoma 2 (Bcl-2) and Bcl-xL were significantly upregulated, whereas the pro-apoptotic proteins BCL2-associated X (Bax), H2O2-induced cleaved caspase-3, and the DNA damage marker, phosphorylated histone (γH2A.X) foci, were significantly downregulated upon histochrome treatment of hCPCs in vitro. Further, prolonged incubation with histochrome alleviated the replicative cellular senescence of hCPCs. In conclusion, we report the protective effect of histochrome against oxidative stress and present the use of a potent and bio-safe cell priming agent as a potential therapeutic strategy in patient-derived hCPCs to treat heart disease.

Oleuropein attenuates hydrogen peroxide-induced autophagic cell death in human adipose-derived stem cells.

Mesenchymal stem cells (MSCs) are multipotent progenitor cells with self-renewing properties; thus, transplanting functionally enhanced MSCs might be a promising strategy for cell therapy against ischemic diseases. However, extensive oxidative damage in ischemic tissue affects the cell fate of transplanted MSCs, eventually resulting in cell damage and autophagic cell death. Oleuropein (OLP) is a bioactive compound isolated from olives and olive oil that harbors antioxidant properties. This study aimed to investigate the potential cytoprotective effects of OLP against oxidative stress and autophagic cell death in MSCs. We found that short-term priming with OLP attenuated H2O2-induced apoptosis by regulating the pro-apoptotic marker Bax and the anti-apoptotic markers Bcl-2 and Mcl-1. Notably, OLP inhibits H2O2 -induced autophagic cell death by modulating autophagy-related death signals, including mTOR (mammalian target of rapamycin), ULK1 (unc-51 like autophagy activating kinase 1), Beclin-1, AMPK (AMP-activated protein kinase), and LC3 (microtubule-associated protein 1a/1b-light chain 3). Our data suggest that OLP might reduce H2O2-induced autophagy and cell apoptosis in MSCs by regulating both the AMPK-ULK axis and the Bcl-2-Mcl-1 axis. Consequently, short-term cell priming with OLP might enhance the therapeutic effect of MSCs against ischemic vascular diseases, which provides an important potential improvement for emerging therapeutic strategies.

Hypoxia-dependent mitochondrial fission regulates endothelial progenitor cell migration, invasion, and tube formation.

Tumor undergo uncontrolled, excessive proliferation leads to hypoxic microenvironment. To fulfill their demand for nutrient, and oxygen, tumor angiogenesis is required. Endothelial progenitor cells (EPCs) have been known to the main source of angiogenesis because of their potential to differentiation into endothelial cells. Therefore, understanding the mechanism of EPC-mediated angiogenesis in hypoxia is critical for development of cancer therapy. Recently, mitochondrial dynamics has emerged as a critical mechanism for cellular function and differentiation under hypoxic conditions. However, the role of mitochondrial dynamics in hypoxia-induced angiogenesis remains to be elucidated. In this study, we demonstrated that hypoxia-induced mitochondrial fission accelerates EPCs bioactivities. We first investigated the effect of hypoxia on EPC-mediated angiogenesis. Cell migration, invasion, and tube formation was significantly increased under hypoxic conditions; expression of EPC surface markers was unchanged. And mitochondrial fission was induced by hypoxia time-dependent manner. We found that hypoxia-induced mitochondrial fission was triggered by dynamin-related protein Drp1, specifically, phosphorylated DRP1 at Ser637, a suppression marker for mitochondrial fission, was impaired in hypoxia time-dependent manner. To confirm the role of DRP1 in EPC-mediated angiogenesis, we analyzed cell bioactivities using Mdivi-1, a selective DRP1 inhibitor, and DRP1 siRNA. DRP1 silencing or Mdivi-1 treatment dramatically reduced cell migration, invasion, and tube formation in EPCs, but the expression of EPC surface markers was unchanged. In conclusion, we uncovered a novel role of mitochondrial fission in hypoxia-induced angiogenesis. Therefore, we suggest that specific modulation of DRP1-mediated mitochondrial dynamics may be a potential therapeutic strategy in EPC-mediated tumor angiogenesis.

Adequate concentration of B cell leukemia/lymphoma 3 (Bcl3) is required for pluripotency and self-renewal of mouse embryonic stem cells via downregulation of Nanog transcription.

B cell leukemia/lymphoma 3 (Bcl3) plays a pivotal role in immune homeostasis, cellular proliferation, and cell survival, as a co-activator or co-repressor of transcription of the NF-κB family. Recently, it was reported that Bcl3 positively regulates pluripotency genes, including Oct4, in mouse embryonic stem cells (mESCs). However, the role of Bcl3 in the maintenance of pluripotency and self-renewal activity is not fully established. Here, we report the dynamic regulation of the proliferation, pluripotency, and self-renewal of mESCs by Bcl3 via an influence on Nanog transcriptional activity. Bcl3 expression is predominantly observed in immature mESCs, but significantly decreased during cell differentiation by LIF depletion and in mESC-derived EBs. Importantly, the knockdown of Bcl3 resulted in the loss of self-renewal ability and decreased cell proliferation. Similarly, the ectopic expression of Bcl3 also resulted in a significant reduction of proliferation, and the self-renewal of mESCs was demonstrated by alkaline phosphatase staining and clonogenic single cell-derived colony assay. We further examined that Bcl3-mediated regulation of Nanog transcriptional activity in mESCs, which indicated that Bcl3 acts as a transcriptional repressor of Nanog expression in mESCs. In conclusion, we demonstrated that a sufficient concentration of Bcl3 in mESCs plays a critical role in the maintenance of pluripotency and the self-renewal of mESCs via the regulation of Nanog transcriptional activity. [BMB Reports 2018; 51(2): 92-97].