• Title/Summary/Keyword: Down-regulated

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Bidirectional Cross-talk Between Estrogen Receptor and Growth Factor Receptors in Breast Cancer Cell (유방암세포에서 에스트로겐 수용체와 성장인자 수용체 사이의 양방향 상호작용)

  • Min, Gyesik
    • Journal of Life Science
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    • v.28 no.2
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    • pp.265-273
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    • 2018
  • Estrogen (E2) is involved in the development and progression of breast cancer and is mediated by estrogen receptor (ER). ER plays important roles in cellular proliferation, migration, invasion and causing drug resistance through diverse cross-talks with epidermal growth factor receptor (EGFR) and insulin-like growth factor-1 receptor (IGF-1R) signaling pathways in breast cancer cells. Breast cancer is caused mainly by break-down of homeostasis of endocrine signaling pathways especially by the uncontrolled expression and increased activities of E2/IGF-1/EGF, ER/G-protein estrogen receptor (GPER)/IGF-1R/EGFR and their intracellular signaling mediators. These changes influence the complex cross-talk between E2 and growth factors' signaling, eventually resulting in the progression of cancer and resistance against endocrine regulators. Thus, elucidation of the molecular mechanisms in stepwise of the cross-talk between E2 and growth factors will contribute to the customized treatment according to the diverse types of breast cancer. In particular, as strategies for the treatment of breast cancer with diverse genotypes and phenotypes, there can be use of aromatase inhibitors and blockers of E2 action for the ER+ hormone-dependent breast cancer cells and use of IGF-1R/EGFR activity blockers for suppression of cancer cell proliferation from the cross-talk between E2 and growth factors. Furthermore, changes in the expression of the ECM molecules regulated by the cross-talk between ER and EGFR/IGF-1R can be used for the targeted therapeutics against the migration of breast cancer cells. Therefore, it is required for the cross-talk among the signaling pathways of ER, GPER, IGF-1R and EGFR concerning cancer progression to be elucidated in more detail at the molecular level.

Effects of Administration of Pyritum on Activation of Osteoblast Cells in Human Body & on Tibia Bone Fracture in Mice (자연동(自然銅)의 투여가 인체의 뼈모세포 활성과 생쥐 정강이뼈 골절에 미치는 영향)

  • Hwang, Ji-Hye;Ahn, Ji-Hyun;Kim, Jin-Teck;Ahn, Sang-Hyun;Kim, Kyung-Ho;Cho, Hyun-Seok;Lee, Seung-Deok;Kim, Eun-Jung;Kim, Kap-Sung
    • Journal of Acupuncture Research
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    • v.26 no.2
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    • pp.159-170
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    • 2009
  • Backgrounds and Objectives: A fracture means a loss of continuity in the substance of bone. Bone differs from other musculoskeletal tissue due to its ability to repair and heal itself without leaving a scar. The cutter head has multinucleated osteoclast cells to resorb the dead bone. The tail, with its conical surface, is lined with osteoblast cells laying down new bone. The conjugation of fracture is a unique biological process regulated by a complex array of signaling molecules and proinflammatory cytokines. Pyritum, one of the important prescriptions in the oriental medicine, has been used for conjugation fracture. The purpose of this study is to evaluate the effects of administration of Pyritum on activation of osteoblast cells in human body & on tibia bone fracture in mice. Materials and Methods : Four weeks aged 30 female DBA mice were used for this study. They were divided three groups, normal group, control group(fracture elicitate mice: FE group) and experimental group(Pyritum administered mice group after fracture elicitation : PA group). Left tibia bones of mice in FE and PA groups were fractured by bone cutters. MG-63 cells in human body th Pyritum in the ratio of 1 mg/m${\ell}$, and the cells were further incubated for 24 hours. Activation of osteoblast was identified using osteopontin, FGF in vitro test. In vivo test, regeneration of fractured tibia through the morphological changes was observed, and also activation of inflammation through NF-${\kappa}$B p65, iNOS, COX-2, osteoblast through osteopontin, FGF and osteoblast's proliferation in each group was measured. Results and Conclusions : 1. In vitro test for activation of osteoblast cells in human body by Pyritum, osteopontin and FGF production were remarkably increased in Pyritum treated MG-63 cells. 2. In regeneration of fractured tibia by Pyritum, fractured area in external tibia morphology was decreased more in the PA group than that of the FE group. Osteogenesis in fractured area was increased more in the PA group than that of the FE group. Also, endochodrial ossification in central area of fracture and osteoid in lateral area of fracture were increased more in the PA group than those of the FE group. 3. In activation of inflammation by Pyritum administered, activation of NF-${\kappa}$B p65, increase of iNOS and COX-2 production were higher in the PA and the FE groups than those of the control group. Especially, the PA group showed higher activation and increase than those of the FE group. 4. In activation of osteoblast by Pyritum, increase of osteopontin, FGF and osteoblast's proliferation were higher in the PA and the FE groups than those of the control group. Especially, the PA group showed higher increase and proliferation than those of the FE group.

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Effects of PGA-LM on CD4+CD25+foxp3+ Treg Cell Activation in Isolated CD4+ T Cells in NC/Nga Mice (NC/Nga 생쥐에서 분리한 T 세포에서 foxp3+ 세포 활성화에 대한 PGA-LM의 효과)

  • Jang, Soon-Nam;Kim, Kum-Lan;Kang, Sang-Mo
    • Microbiology and Biotechnology Letters
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    • v.37 no.2
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    • pp.160-169
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    • 2009
  • Poly-$\gamma$-glutamic acid ($\gamma$-PGA) was mixed natural flora of Bacillus subtilis, contaminated from cooked soybeans. Also, it was performed to find out the antiallergic activity by using NC/Nga mice, in vitro. The $\gamma$-PGA (PGA-HM : PGA-high molecular weight), Molecular weight 300 kDa, was decomposed and made PGA-LM (PGA-low molecular weight) which has molecular weight below 30 kDa by sonication. Therefore, it was same result between PGA-HM and PGA-LM, and reported PGA-LM as basic result. We found that PGA-LM contains antiallergic efficacy that inhibit B cells and Th2 cells activation from isolated CD4+T cells in NC/Nga atopic dermatitis model mice, and not show a cytotoxicity in the hFCs. To investigate the effects of these PGA-LM in vitro, isolation of splenic B cell and CD4+ T cells in atopic dermatitis mice were used. To elucidate the role of PGA-LM in anti-CD40+ interleukin-4 (IL-4)-mediated B-cell activation, showed that the capacity of B cells to expression IL-$1\beta$, IL-6, and TNF-$\alpha$ mRNA down-regulated, and IL-10 mRNA up-regulation by PGA-LM treatment, but it had no effect on TGF-$\beta$ expression. In addition to CD4+IFN-$\gamma$+ and CD4+CD25+foxp3+, the functions of PGA-LM in the development of the CD4+CD25+foxp3+ and CD4+IFN-$\gamma$+cells, the phenotype and functions of PGA-LM induced CD4+CD25+foxp3+, and CD4+IFN-$\gamma$+cells in CD4+T cells. These results suggested that PGA-LM could change cytokine production and generate CD4+CD25+foxp3+ Tregs in NC/Nga mice, and may be effective for immunotherapy in patients with AD.

Hepatoprotective Effects of Oyster Hydrolysate on Lipopolysaccharide/D-Galactosamine-Induced Acute Liver Injury in Mice (Lipopolysaccharide/D-Galactosamine에 의해 유도된 급성 간 손상 생쥐모델에서 굴가수분해물의 간 보호 효과)

  • Ryu, Ji Hyeon;Kim, Eun-Jin;Xie, Chengliang;Nyiramana, Marie Merci;Siregar, Adrian S.;Park, Si-Hyang;Cho, Soo Buem;Song, Dae Hyun;Kim, Nam-Gil;Choi, Yeung Joon;Kang, Sang Soo;Kang, Dawon
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.46 no.6
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    • pp.659-670
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    • 2017
  • Oxidative stress and inflammation are key factors responsible for progression of liver injury. A variety of functions of oyster hydrolysate (OH) are affected by their antioxidant and anti-inflammatory activities. However, little is known regarding the effects of OH on a liver injury model. This study was performed to evaluate the effects of OH on acute liver injury induced by lipopolysaccharide/D-galactosamine (LPS/D-GalN) in mice. Experimental groups were divided into six groups as follows (each group, n=10): control (saline), LPS/D-GalN, LPS/D-GalN+OH (100 mg/kg), LPS/D-GalN+OH (200 mg/kg), LPS/D-GalN+OH (400 mg/kg), and LPS/D-GalN+silymarin (25 mg/kg, positive control). The experimental acute liver injury model was induced with LPS ($1{\mu}g/kg$) and D-GalN (400 mg/kg). We first analyzed antioxidant and anti-inflammatory activities in OH. OH showed high DPPH and ABTS radical scavenging activities and reduced ROS generation in Chang cells in a dose-dependent manner. In addition, OH showed anti-inflammatory activities, such as inhibition of cyclooxygenase-2 and 5-lipooxygenase. Treatment with OH down-regulated tumor necrosis factor $(TNF)-{\alpha}$, interleukin (IL)-6, and $IL-1{\alpha}$ expression levels in LPS-stimulated RAW264.7 cells. OH significantly reduced LPS/D-GalN-induced increases in the concentrations of alanine transaminase and aspartate aminotransferase in serum. In the LPS/D-GalN group, liver tissues exhibited apoptosis of hepatocytes with hemorrhages. These pathological alterations were ameliorated by OH treatment. Consistently, hepatic catalase activity was low in the LPS/D-GalN group compared to the control group, and catalase activity was significantly restored by OH treatment (P<0.05). Furthermore, OH markedly reduced the LPS/D-GalN-induced increase in $TNF-{\alpha}$, $IL-1{\beta}$, and IL-6 levels in liver tissue. Taken together, these results show that OH has hepatoprotective effects on LPS/D-GalN-induced acute liver injury via inhibition of oxidative stress and inflammation, suggesting that OH could be used as a health functional food and potential therapeutic agent for acute liver injury.

Increases in Doxorubicin Sensitivity and Radioiodide Uptake by Transfecting shMDR and Sodium/Iodide Symporter Gene in Cancer Cells Expressing Multidrug Resistance (다약제내성 암세포에서 shMDR과 Sodium/Iodide Symporter 유전자의 이입에 의한 Doxorubicin 감수성과 방사성옥소 섭취의 증가)

  • Ahn, Sohn-Joo;Lee, Yong-Jin;Lee, You-La;Choi, Chang-Ik;Lee, Sang-Woo;Yoo, Jeong-Soo;Ahn, Byeong-Cheol;Lee, In-Kyu;Lee, Jae-Tae
    • Nuclear Medicine and Molecular Imaging
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    • v.41 no.3
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    • pp.209-217
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    • 2007
  • Purpose: Multidrug resistance (MDR) of the cancer cells related to mdr1 gene expression can be effectively treated by selective short hairpin RNA for mdr1 gene (shMDR). Sodium/iodide symporter (NIS) gene is well known to have both reporter and therapeutic gene characteristics. We have co-transfected both shMDR and NIS gene into colon cancer cells (HCT15 cell) expressing MDR and Tc-99m sestamibi and I-125 uptake were measured. In addition, cytotoxic effects of doxorubicin and I-131 therapy were also assessed after transfection. Material and Methods: At first, shMDR was transfected with liposome reagent into human embryonic kidney cells (HEK293) and HCT cells. shMDR transfection was confirmed by RT-PCR and western blot analysis. Adenovirus expressing NIS (Ad-NIS) gene and shMDR (Ad-shMDR) were co-transfected with Ad-NIS into HCT15 cells. Forty-eight hours after infection, inhibition of P-gycoprotein (Pgp) function by shMDR was analyzed by a change of Tc-99m sestamibi uptake and doxorubicin cytotoxicity, and functional activity of induced NIS gene expression was assessed with I-125 uptake assay. Results: In HEK293 cells transfected with shMDR, mdr1 mRNA and Pgp protein expressions were down regulated. HCT15 cells infected with 20 MOI of Ad-NIS was higher NIS protein expression than control cells. After transfection of 300 MOI of Ad-shMDR either with or without 10 MOI of Ad-NIS, uptake of Tc-99m sestamibi increased up to 1.5-fold than control cells. HCT15 cells infected with 10 MOI of Ad-NIS showed approximately 25-fold higher I-125 uptake than control cells. Cotransfection of Ad-shMDR and Ad-NIS resulted in enhanced cytotoxic by doxorubicin in HCT15 cells. I-131 treatment on HCT15 cells infected with 20 MOI of Ad-NIS revealed increased cytotoxic effect. Conclusion: Suppression of mdr1 gene expression, retention of Tc-99m sestamibi, enhanced doxorubicin cytotoxicity and increases in I-125 uptake were achieved in MDR expressing cancer cell by co-transfection of shMDR and NIS gene. Dual therapy with doxorubicin and radioiodine after cotransfection shMDR and NIS gene can be used to overcome MDR.

Analysis of Lipogenic and Myogenic Gene Expressions in Energy Restricted Broiler Chickens (육계의 에너지 제한 사양에 따른 지방 합성 및 근육 발달 관련 유전자의 발현 양상 비교 분석)

  • Moon, Yang-Soo
    • Korean Journal of Poultry Science
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    • v.36 no.4
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    • pp.301-309
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    • 2009
  • The present study was conducted to determine the effect of energy restricted (ER) diet on the expressions of lipogenic genes in liver and myogenic genes in muscle tissue of broiler chickens. Energy restriction was accomplished by providing chicks with 70% (ER70) or 85% (ER85) energy level of control diet intake. Energy restricted groups of chickens were restricted for 7 days, starting at 8 days of age. Ad libitum feeding was resumed after the restriction period, and continued through the end of the experiment. The body weight of chickens in the restricted groups gained less during the energy restriction period (P<0.05). The body weight of the ER groups were similar to the control group during the re-alimentation period. However, the body weight of the ER70 group did not catch up with that of the control group by 35 days of age. The energy restrictions during early life of chicks decreased the contents of triglycerides and cholesterol in blood (P<0.05), but those were not different among treatments after re-alimentation. The genes of fatty acid synthase (FAS) and transcription factors including SREBP and PPARγ were down regulated by restriction regimen only in ER70 (P<0.05). However, those genes were not completely recovered after re-alimentation in ER70 group. The RNA expression levels of Myo-D, Myf-5 and myogenin in all treatment groups were decreased by restriction regimen when compared with control group (P<0.05). Myogenin was highly expressed after re-alimentation, but the other genes were not different among groups. These results suggest that ER85 group shows the best growth performance by re-alimentation and the higher muscle differentiation by expressing myogenin.

Hsp90 Inhibitor Induces Cell Cycle Arrest and Apoptosis of Early Embryos and Primary Cells in Pigs

  • Son, Myeong-Ju;Park, Jin-Mo;Min, Sung-Hun;Hong, Joo-Hee;Park, Hum-Dai;Koo, Deog-Bon
    • Reproductive and Developmental Biology
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    • v.35 no.1
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    • pp.33-45
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    • 2011
  • Heat shock protein 90 (Hsp90) is ATPase-directed molecular chaperon and affects survival of cancer cell. Inhibitory effect of Hsp90 by inducing cell cycle arrest and apoptosis in the cancer cell was reported. However, its role during oocyte maturation and early embryo development is very insufficient. In this study, we traced the effects of Hsp90 inhibitor, 17-allylamino-17-demethoxygeldanamycin (17-AAG), on meiotic maturation and early embryonic development in pigs. We also investigated several indicators of developmental potential, including structural integrity, gene expression (Hsp90-, cell cycle-, and apoptosis-related genes), and apoptosis, which are affected by 17-AAG. Then, we examined the roles of Hsp90 inhibitor on viability of primary cells in pigs. Porcine oocytes were cultured in the NCSU-23 medium with or without 17-AAG for 44 h. The proportion of GV arrested oocytes was significantly different between the 17-AAG treated and untreated group (78.2 vs 34.8%, p<0.05). After completion of meiotic maturation, the proportion of MII oocytes was lower in the 17-AAG treated group than in the control group (27.9 vs 71.0%, p<0.05). After IVF, the percentage of penetrated oocytes was significantly lower in the 17-AAG treated group (25.2%), resulting in lower normal pronucleus formation (2PN of 14.6%). Therefore, the inhibition of meiotic progression by Hsp90 inhibitor played a critical role in fertilization status. Porcine embryo were cultured in the PZM-3 medium with or without 17-AAG for 6 days. In result, significant differences in developmental potential were detected between the embryos that were cultured with or without 17-AAG. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) showed that the number of containing fragmented DNA at the blastocyst stage increased in the 17-AAG treated group compared with control (7.5 vs 4.4, respectively). Blastocysts that developed in the 17-AAG treated group had low structural integrity and high apoptotic nuclei than those of the untreated control, resulting in decrease the embryonic qualities of preimplantation porcine blastocysts. The mRNA expressions of cell cycle-related genes were down-regulated in the 17-AAG treated group compared with control. Also, the expression of the pro-apoptotic gene Bax increased in 17-AAG treated group, whereas expression of the anti-apoptotic gene Bel-XL decreased. However, the expression of ER stress-related genes did not changed by 17-AAG. Cultured pESF cells were treated with or without 17-AAG and used for MIT assay. The results showed that viability of pESF cells were decreased by treatment of 17-AAG ($2{\mu}M$) for 24 hr. These results indicated that 17-AAG decreased cell proliferation and increased cell death. Expression patterns Hsp90 complex genes (Hsp70 and p23), cell cycle-related genes (cdc2 and cdc25c) and apoptosis-related genes (Bax and Bcl-XL) were significantly changed by using RT-PCR analysis. The spliced form of pXbp-1 product (pXbp-1s) was detected in the tunicamycin (TM) treated cells, but it is not detected in 17-AAG treated cells. In conclusion, Hsp90 appears to play a direct role in porcine early embryo developmental competence including structural integrity of blastocysts. Also, these results indicate that Hsp90 is closely associated with cell cycle- and apoptosis-related genes expression in developing porcine embryos.

A Study on the International Carriage of Cargo by Air under the Montreal Convention-With respect to the Air Waybill and the Liability of Air Carrier (몬트리올 협약상 국제항공화물운송에 관한 연구 - 항공화물운송장과 항공운송인의 책임을 중심으로 -)

  • Lee, Kang-Bin
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.49
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    • pp.283-324
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    • 2011
  • The purpose of this paper is to research the air waybill and the carrier's liability in respect of the carriage of cargo by air under the Montreal Convention of 1999. The Warsaw Convention for the unification of certain rules for international carriage by air was adopted in 1929 and modified successively in 1955, 1961, 1971, 1975 and 1999. The Montreal Convention of 1999 modernized and consolidated the Warsaw Convention and related instruments. Under the Montreal Convention, in respect of the carriage of cargo, the air waybill shall be made out by the consignor. If, at the request of the consignor, the carrier makes it out, the carrier shall be deemed to have done so on behalf of the consignor. The air waybill shall be made out in three orignal parts. Under the Montreal Convention, the consignor shall indemnify the carrier against all damages suffered by the carrier or any other person to whom the carrier is liable, by reason of the irregularity, incorrectness or incompleteness of the particulars and statement furnished by the consignor or on its behalf. The air waybill is not a document of title or negotiable instrument. Under the Montreal Convention, the air waybill is prima facie evidence of the conclusion of the contract, of the acceptance of the cargo and of the conditions of carriage. If the carrier carries out the instructions of the consignor for the disposition of the cargo without requiring the production of the part of the air waybill, the carrier will be liable, for any damage which may be accused thereby to any person who is lawfully in possession of the part of the air waybill. Under the Montreal Convention, the carrier is liable by application of principle of strict liability for the damage sustained during the carriage of cargo by air. The carrier is liable for the destruction or loss of, or damage to cargo and delay during the carriage by air. The period of the carriage by air does not extend to any carriage by land, by sea or by inland waterway performed outside an airport. Under the Montreal Convention, the carrier's liability is limited to a sum of 17 Special Drawing Rights per kilogramme. Any provision tending to relieve the carrier of liability or to fix a lower limit than that which is laid down in this Convention shall be and void. Under the Montreal Convention, if the carrier proves that the damage was caused by the negligence or other wrongful act or omission of the person claiming compensation, or the person from whom he derives his rights, the carrier shall be wholly or partly exonerated from ist liability to the claimant to the extent that such negligence or wrongful act or omission caused the damage. Under the Montreal Convention, any action for damages, however founded, whether under this Convention or in contract or in tort or otherwise, can only be brought subject to the conditions and such limits of liability as are set out in this Convention. Under the Montreal Convention, in the case of damage the person entitled to delivery must complain to the carrier forthwith after the discovery of the damage, and at the latest, within fourteen days from the date of receipt of cargo. In the case of delay, the complaint must be made at the latest within twenty-one days from the date on which the cargo has been placed at his disposal. if no complaint is made within the times aforesaid, no action shall lie against the carrier, save in the case of fraud on its part. Under the Montreal Convention, the right to damage shall be extinguished if an action is not brought within a period of two years, reckoned from the date of arrival at the destination, or from the date on which the aircraft ought to have arrived, or from the date on which the carriage stopped. In conclusion, the Montreal Convention has main outstanding issues with respect to the carrier's liability in respect of the carriage of cargo by air as follows : The amounts of limits of the carrier's liability, the duration of the carrier's liability, and the aviation liability insurance. Therefore, the conditions and limits of the carrier's liability under the Montreal Convention should be readjusted and regulated in detail.

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BCR/ABL mRNA Targeting Small Interfering RNA Effects on Proliferation and Apoptosis in Chronic Myeloid Leukemia

  • Zhu, Xi-Shan;Lin, Zi-Ying;Du, Jing;Cao, Guang-Xin;Liu, Gang
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.12
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    • pp.4773-4780
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    • 2014
  • Background: To investigate the effects of small interference RNA (siRNA) targeting BCR/ABL mRNA on proliferation and apoptosis in the K562 human chronic myeloid leukemia (CML) cell line and to provide a theoretical rationale and experimental evidence for its potential clinical application for anti-CML treatment. Materials and Methods: The gene sequence for BCR/ABL mRNA was found from the GeneBank. The target gene site on the BCR/ABL mRNA were selected according to Max-Planck-Institute (MPI) and rational siRNA design rules, the secondary structure of the candidate targeted mRNA was predicted, the relevant thermodynamic parameters were analyzed, and the targeted gene sequences were compared with BLAST to eliminate any sequences with significant homology. Inhibition of proliferation was evaluated by MTT assay and colony-formation inhibiting test. Apoptosis was determined by flow cytometry (FCM) and the morphology of apoptotic cells was identified by Giemsa-Wright staining. Western blotting was used to analyze the expression of BCR/ABL fusion protein in K562 cells after siRNA treatment. Results: The mRNA local secondary structure calculated by RNA structure software, and the optimal design of specific siRNA were contributed by bioinformatics rules. Five sequences of BCR/ABL siRNAs were designed and synthesized in vitro. Three sequences, siRNA1384, siRNA1276 and siRNA1786, which showed the most effective inhibition of K562 cell growth, were identified among the five candidate siRNAs, with a cell proliferative inhibitory rate nearly 50% after exposure to 12.5nmol/L~50nmol/L siRNA1384 for 24,48 and 72 hours. The 50% inhibitory concentrations ($IC_{50}$) of siRNA1384, siRNA1276 and siRNA1786 for 24hours were 46.6 nmol/L, 59.3 nmol/L and 62.6 nmol/L, respectively, and 65.668 nmol/L, 76.6 nmol/L, 74.4 nmol/L for 72 hours. The colony-formation inhibiting test also indicated that, compared with control, cell growth of siRNA treated group was inhibited. FCM results showed that the rate of cell apoptosis increased 24 hours after transfecting siRNA. The results of annexinV/PI staining indicated that the rate of apoptosis imcreased (1.53%, 15.3%, 64.5%, 57.5% and 21.5%) following treamtne with siRNAs (siRNA34, siRNA372, siRNA1384, siRNA1276 and siRNA1786). Morphological analysis showed td typical morphologic changes of apoptosis such as shrunken, fragmentation nucleus as well as "apoptotic bodies" after K562 cell exposure to siRNA. Western blot analysis showed that BCR/ABL protein was reduced sharply after a single dose of 50nmol/L siRNA transfection. Conclusions: Proliferation of K562 cells was remarkbly inhibited by siRNAs (siRNA1384, siRNA1276 and siRNA1786) in a concentration-dependent manner in vitro, with effective induction of apoptosis at a concentration of 50 nmol/L. One anti-leukemia mechanism in K562 cells appeared that BCR/ABL targeted protein was highly down-regulated. The siRNAs (siRNA1384, siRNA1276 and siRNA1786) may prove valuable in the treatment of CML.

The Relationship between Intracellular Protein Kinase C Concentration and Invasiveness in U-87 Malignant Glioma Cells (교모세포종 세포주 U-87에서 세포내 PKC 농도와 종양침습성과의 상관 관계)

  • Ji, Cheol;Cho, Kyung-Keun;Lee, Kyung Jin;Park, Sung Chan;Cho, Jung Ki;Kang, Joon Ki;Choi, Chang Rak
    • Journal of Korean Neurosurgical Society
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    • v.30 no.3
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    • pp.263-271
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    • 2001
  • Objective : Glioblastomas, the most common type of primary brain tumors, are highly invasive and cause massive tissue destruction at both the tumor invading edges and in areas that are not in direct contact with glioma cells. As a result, patients with high-grade gliomas are faced with a poor prognosis. Such grim statistics emphasize the need to better understand the mechanisms that underlie glioma invasion, as these may lead to the identification of novel targets in the therapy of high grade gliomas. Protein kinase C(PKC) is a family of serine/threonine kinases and an important signal transduction enzyme that conveys signals generated by ligand-receptor interaction at the cell surface to the nucleus. PKC appears to be critical in regulating many aspects of glioma biology. The purpose of this study was to assess accurately the role of PKC in the invasion regulation of human gliomas based on hypothesis that protein kinase C(PKC) is functional in the process of glial tumor cell invasion. Method : To test this hypothesis, U-87 malignant glioma cell line intracellular PKC levels were up and down regulated and their invasiveness was tested. Intracellular PKC level was characterized using PKC activity assays. Invasion assays including barrier migration and spheroid confrontation were used to study the relationship between PKC concentration and invasiveness. Result : The cell line which were treated by PKC inhibitor tamoxifen and hypericin exhibited decreased PKC activity and decreased invasive abilities dose dependently both in matrigel invasion assay and tumor spheroid fetal rat brain aggregates(FRBA) confrontation assay. However, the cell line that was treated by PKC activator 12-O-tetradecanylphorbol-13acetate(TPA) did not exhibit increases in either PKC activity or invasive ability. Conclusion : These studies suggest that PKC may be a useful molecular target for the chemotherapy of glioblastoma and other malignancies and that a therapeutic approach based on the ability of PKC inhibitors may be helpful in preventing invasion.

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