• Biomedical Science Letters
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• v.23 no.1
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• pp.1-7
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• 2017

It is known that acute myeloid leukemia (AML) is a heterogeneous blood cancer, which is enormously propagated by self-renewing leukemia stem cells (LSCs). The persistence of LSCs after chemotherapy can contribute to minimal residual disease and relapse by LSCs can be evoked promptly. Elucidating special molecules and cellular activity of LSCs is an extremely important to eliminate AML. Despite an increasing understanding of the origin of LSCs by incessant study, AML still remains a notorious disease with high mortality. An exact identification of the LSCs that sustain the proliferation of neoplastic clone is a fundamental issue in AML treatment. CD34+CD38- conventional phenotype is overall regarded as LSCs, but it has a limitation that is still hard to demarcate exactly due to similarity with normal hematopoietic stem cells (HSCs). Not all primary blasts and progenitors have equal function, thus a bona fide marker for identifying LSCs from HSCs is needed in hematologic malignancy, especially in AML. These findings have direct important implications in both in mechanistic study of LSCs as well as in the strategies of more effective therapies. In this review, I briefly summarized current advances in LSCs biology, focusing on membrane markers and a functional behavior of LSCs in AML treatment with monoclonal antibodies. Ultimately, it may be helpful in overviewing the status of LSC research, while expecting the clinic benefits of target therapy by specific inhibition.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.80-80
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• 1997

The object of this study was to develop a gene therapy strategy for ovarian cancer. We have previously shown that AV with a L-plastin (LP) promoter infects breast and ovarian cancer cells and expressed ${\beta}$-galactosidase cDNA in preference to normal fibroblast cells and hematopoietic cells. We now report on the cytotoxicity of Ad.LP.CD, an AV carrying a CD cDNA which converts the pro-drug, 5-Fluorocytosine (5-FC) into the toxic drug 5-Fluorouracil (5-FU). Infection of Ad.LP.CD into either 293 cells or ovarian cancer cells generated the functional CD as measured by HPLC analysis. Using a ratio of AV to OVCAR3 cell of 100 and a 5-FC concentration of 100 ${\mu}$M, we achieve an over 95 % of cell growth inhibition. We are using flow cytometry analysis for ${\beta}$ -galactosidase and ovarian cancer associated folate receptor to screen primary ascites samples for infectivity after infection with an adenoviral vector, i.e., Ad.LP.LacZ. This vector system may be of value in the treatment of microscopic disease of ovarian cancer in the peritoneal cavity.

• Biomolecules & Therapeutics
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• v.15 no.4
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• pp.230-234
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• 2007

In anti-cancer therapies, radiotherapy and chemotherapy show a superior inhibition effect on cancer cell growth, but those are very toxic to normal tissues and organs. Particularly, drugs for neutropenia, one of chemotherapy agents, which suppress the function of bone marrow, are needed to be controlled in terms of their dosage and therapy period because of their side effect. Phellinus linteus polysaccharide (PL) has been reported to increase the number of splenocytes and bone marrow cells. PL has been shown to decrease the side effects of cyclophosphamide (CYC) treatment to the cancer patients. PL showed no effects in semisolid clonogenic assay, suggesting that PL doesn't contain substantial compounds to substitute for colony stimulating factors (CSFs). On the other hand, PL increased the expression of SCF, IL-3, GM-CSF, TPO genes. These results indicate that PL may promote the growth and proliferation of splenocytes and bone marrow cells through indirect or CSFs-dependent pathway, which may lead to a hematopoiesis.

• BMB Reports
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• v.34 no.5
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• pp.421-427
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• 2001

Osteoclasts, cells primarily involved in bone resorption, originate from the hematopoietic precursor cells of the monocyte/macrophage lineage and differentiate into multinucleated mature forms. We developed an in vitro osteoclast culture system using embryonic chicken bone marrow cells. This culture system can be utilized in studies on the differentiation and function of osteoclasts. Phosphatidylinositol 3-kinase (PI3-kinase) and mitogen-activated protein kinases (MAPKs) have been implicated in diverse cellular functions including proliferation, migration, and survival. Using the developed avian osteoclast culture system, we examined the involvement of these kinases in osteoclast differentiation by employing specific inhibitors of the kinases. We Found that the inhibition of the PI 3-kinase, p38, or ERK interfered with osteoclast formation, suggesting that the signaling pathways that involve these molecules participate in the process of chicken osteoclast differentiation.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3025-3033
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• 2016

Chronic myeloid leukaemia (CML) is a clonal myeloproliferative hematopoietic stem cell disorder. Deregulated BCR-ABL fusion tyrosine kinase activity is the main cause of CML disease pathogenesis, making BCR-ABL an ideal target for inhibition. Current tyrosine kinase inhibitors (TKIs) designed to inhibit BCR-ABL oncoprotein activity, have completely transformed the prognosis of CML. Interruption of TKI treatment leads to minimal residual disease reside (MRD), thought to reside in TKI-insensitive leukaemia stem cells which remain a potential reservoir for disease relapse. This highlights the need to develop new therapeutic strategies for CML either as small molecule master TKIs or phytopharmaceuticals derived from nature to achieve chronic molecular remission. This review outlines the past, present and future therapeutic approaches for CML including coverage of relevant mechanisms, whether ABL dependent or independent, and epigenetic factors responsible for developing resistance against TKIs. Appearance of mutant clones along the course of therapy either pre-existing or induced due to therapy is still a challenge for the clinician. A proposed in-vitro model of generating colony forming units from CML stem cells derived from diagnostic samples seems to be achievable in the era of high throughput technology which can take care of single cell genomic profiling.

• IMMUNE NETWORK
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• v.3 no.4
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• pp.287-294
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• 2003

Background: In kidney transplantation, donor specific transfusion may induce tolerance as a result of some immune regulatory cells against the graft. In organ transplantation, the immune state arises from a relationship between the immunocompromised graft and the immunocompetent host. However, a reverse immunological situation exists between the graft and the host in hematopoietic stem cell transplantation (HSCT). In addition, early IL-2 injections after an allogeneic murine HSCT have been shown to prevent lethal graft versus host disease (GVHD) due to CD4+ cells. We investigated the induction of the regulatory CD4+CD25+ cells after a transfusion of irradiated recipient cells with IL-2 into a donor. Methods: The splenocytes (SP) were obtained from 6 week-old BALB/c mice ($H-2^d$) and irradiated as a single cell suspension. The donor mice (C3H/He, $H-2^k$) received $5{\times}10^6$ irradiated SP, and 5,000 IU IL-2 injected intraperitoneally on the day prior to HSCT. The CD4+CD25+ cell populations in SP treated C3H/He were analyzed. In order to determine the in vivo effect of CD4+CD25+ cells, the lethally irradiated BALB/c were transplanted with $1{\times}10^7$ donor BM and $5{\times}10^6$ CD4+CD25+ cells. The other recipient mice received either $1{\times}10^7$ donor BM with $5{\times}10^6$ CD4+ CD25- cells or the untreated SP. The survival and GVHD was assessed daily by a clinical scoring system. Results: In the MLR assay, BALB/c SP was used as a stimulator with C3H/He SP, as a responder, with or without treatment. The inhibition of proliferation was $30.0{\pm}13%$ compared to the control. In addition, the MLR with either the CD4+CD25+ or CD4+CD25- cells, which were isolated by MidiMacs, from the C3H/He SP treated with the recipient SP and IL-2 was evaluated. The donor SP treated with the recipient cells and IL-2 contained more CD4+CD25+ cells ($5.4{\pm}1.5%$) than the untreated mice SP ($1.4{\pm}0.3%$)(P<0.01). There was a profound inhibition in the CD4+CD25+ cells ($61.1{\pm}6.1%$), but a marked proliferation in the CD4+CD25- cells ($129.8{\pm}65.2%$). Mice in the CD4+CD25+ group showed low GVHD scores and a slow progression from the post-HSCT day 4 to day 9, but those in the control and CD4+CD25- groups had a high score and rapid progression (P<0.001). The probability of survival was 83.3% in the CD4+CD25+ group until post-HSC day 35 and all mice in the control and CD4+CD25- groups died on post-HSCT day 8 or 9 (P=0.0105). Conclusion: Donor graft engineering with irradiated recipient SP and IL-2 (recipient specific transfusion) can induce abundant regulatory CD4+CD25+ cells to prevent GVHD.

• Archives of Pharmacal Research
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• v.29 no.3
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• pp.218-223
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• 2006

Erythropoietin (EPO), a hematopoietic factor, is required for normal erythrocyte developments, but it has been demonstrated to have many other functions, and its receptor is localized in other tissues. In the present study, we investigated whether EPO can promote other cell proliferation and possible molecular mechanisms. EPO restored the inhibition of the RAW264.7 and PC12 cell growth by fetal bovine serum (FBS) withdrawal in a dose dependent manner, but not that of other cell types tested. The restoring effect of EPO was completed when the RAW264.7 cells were cultured in the medium containing as low as 3% of FBS, and 10 U/mL EPO could replace FBS. The restoring effect of EPO in the RAW264.7 cells was associated with the increased of c-Fos and c-Jun expression as well as AP-1 activation. These data demonstrate that EPO can stimulate RAW264. 7 cell as well as PC12 cell growth even when the cells were cultured without FBS or in the presence of small amounts of FBS in the medium, and this stimulating effect is associated with the activation of AP-1 transcription factor.

• The Korean Journal of Pain
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• v.30 no.2
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• pp.86-92
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• 2017

Osteoblasts, originating from mesenchymal cells, make the receptor activator of the nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) in order to control differentiation of activated osteoclasts, originating from hematopoietic stem cells. When the RANKL binds to the RANK of the pre-osteoclasts or mature osteoclasts, bone resorption increases. On the contrary, when OPG binds to the RANK, bone resorption decreases. Denosumab (AMG 162), like OPG (a decoy receptor), binds to the RANKL, and reduces binding between the RANK and the RANKL resulting in inhibition of osteoclastogenesis and reduction of bone resorption. Bisphosphonates (BPs), which bind to the bone mineral and occupy the site of resorption performed by activated osteoclasts, are still the drugs of choice to prevent and treat osteoporosis. The merits of denosumab are reversibility targeting the RANKL, lack of adverse gastrointestinal events, improved adherence due to convenient biannual subcutaneous administration, and potential use with impaired renal function. The known adverse reactions are musculoskeletal pain, increased infections with adverse dermatologic reactions, osteonecrosis of the jaw, hypersensitivity reaction, and hypocalcemia. Treatment with 60 mg of denosumab reduces the bone resorption marker, serum type 1 C-telopeptide, by 3 days, with maximum reduction occurring by 1 month. The mean time to maximum denosumab concentration is 10 days with a mean half-life of 25.4 days. In conclusion, the convenient biannual subcutaneous administration of 60 mg of denosumab can be considered as a first-line treatment for osteoporosis in cases of low compliance with BPs due to gastrointestinal trouble and impaired renal function.

• International Journal of Oral Biology
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• v.32 no.4
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• pp.127-133
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• 2007

Oral squamous cell carcinoma (OSCC) is the most common malignancy and is a major cause of worldwide cancer mortality. The proto-oncogene c-myb plays an important role in regulation of cell growth and differentiation, and it is expressed at high levels in hematopoietic cells and many other types of cancers. However, the function of c-myb is not well known in OSCC. The present study aimed to reveal the function of c-myb and to test the alternation of cell growth and signaling by c-myb in OSCC. In this study, c-myb and dominant-negatibe myb(DNmyb) were expressed in an adenovirus-mediated gene delivery system to KB cells. The over-expressed c-myb brought increased cellular proliferation compared with control cells. However, DN-myb infected KB cells showed significant reduction of cell growth and enhanced induction of apoptosis to activate PARP and caspase 9. c-myb induced increase of IGF-I, -II and IGF-IR expressions while DN-myb down-regulated these expression. Activation of ERK and Akt/PKB pathway was shown only in c-myb transduced cells. These findings suggest that the role of c-myb in cell growth of oral cancer cells is partially mediated through the modulation of IGFs, ERK and Akt/PKB. From this results, DN-myb is strongly recommended as a curable gene for the treatment of c-myb dependent malignancies such as OSCC.

• Biomolecules & Therapeutics
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• v.20 no.3
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• pp.280-285
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• 2012

The developing embryo naturally experiences relatively low oxygen conditions in vivo. Under in vitro hypoxia, mouse embryonic stem cells (mESCs) lose their self-renewal activity and display an early differentiated morphology mediated by the hypoxia-inducible factor-$1{\alpha}$ (HIF-$1{\alpha}$). Previously, we demonstrated that histone deacetylase (HDAC) is activated by hypoxia and increases the protein stability and transcriptional activity of HIF-$1{\alpha}$ in many human cancer cells. Furthermore HDAC1 and 3 mediate the differentiation of mECSs and hematopoietic stem cells. However, the role of HDACs and their inhibitors in hypoxia-induced early differentiation of mESCs remains largely unknown. Here, we examined the effects of several histone deacetylase inhibitors (HDACIs) on the self-renewal properties of mESCs under hypoxia. Inhibition of HDAC under hypoxia effectively decreased the HIF-$1{\alpha}$ protein levels and substantially improved the expression of the LIF-specific receptor (LIFR) and phosphorylated-STAT3 in mESCs. In particular, valproic acid (VPA), a pan HDACI, showed dramatic changes in HIF-$1{\alpha}$ protein levels and LIFR protein expression levels compared to other HDACIs, including sodium butyrate (SB), trichostatin A (TSA), and apicidin (AP). Importantly, our RT-PCR data and alkaline phosphatase assays indicate that VPA helps to maintain the self-renewal activity of mESCs under hypoxia. Taken together, these results suggest that VPA may block the early differentiation of mESCs under hypoxia via the destabilization of HIF-$1{\alpha}$.