• Journal of Integrative Natural Science
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• v.11 no.2
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• pp.107-112
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• 2018

p38 MAP kinase belongs to the Mitogen-activated protein (MAP) kinase family; a serine/threonine kinase. It plays an important role in intracellular signal transduction pathways. It is associated with the development and progression of various cancer types making it a crucial drug target. Present study involves the HQSAR analysis of recently reported imidazo[1,2-b]pyridazine derivatives as p38 MAP kinase antagonists. The model was generated with Atom (A), bond (B), chirality (Ch), and hydrogen (H) parameters and with different set of atom counts to improve the model. An acceptable HQSAR model ($q^2=0.522$, SDEP=0.479, NOC=5, $r^2=0.703$, SEE=0.378, BHL=97) was developed which exhibits good predictive ability. A contribution map for the most active compound (compound 17) illustrated that hydrogen and nitrogen atoms in the ring A and ring B, as well as nitrogen atom in ring C and the hydrogen atom in the ring D provided positive activity in inhibitory effect while, the least active compound (compound 05) possessed negative contribution to inhibitory effect. Hence, analysis of produced HQSAR model can provide insights in the designing potent and selective p38 MAP kinase antagonists.

• Biomedical Science Letters
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• v.2 no.1
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• pp.21-30
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• 1996

MAP kinases are a family of serine/threonine specific protein kinases becoming activated in response to different proliferative stimuli by phosphorylation at both threonine and tyrosine residue. Present study shows that MAP kinase was purified from P388 murine leukema cells by SP sephadex C-50, phenyl superose and Mono Q column chromatography and identified with anti-ERKl antibody by western blotting. Immnublotting analysis to the crude extract of P388 cell lysate shows 44 kD and other minor bands but partial purified fraction eluted from phenyl supherose column have 44kD and 66 kD isoform. Subcloned GST-fusion protein from N-terminal of $p56^{kk}$ was tested as a substrate for MAP kinase phosphorylation. It was showed that the wild type and mutant forms(S42A) were fully phosporylated by purified MAP kinase fraction as com-pare with the other mutant form(S59A). This finding suggest that those GST-fusion proteins may be used as substrate for the in vitro test of MAP kinase.

• BMB Reports
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• v.32 no.4
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• pp.379-384
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• 1999

Taxol, a natural product with significant anti-tumor activity, stabilizes microtubules and arrests cells in the G2/M phase of the cell cycle. It has been reported that taxol has additional effects on the cell such as an increase in tyrosine phosphorylation of proteins and activation of mitogen-activated protein (MAP) kinase. This phosphorylated kinase translocates into the nucleus and phosphorylates its substrate c-jun, c-fos, ATF2, and ATF3. The MAP kinase family is comprised of key regulatory proteins that control the cellular response to both proliferation and stress signals. First examination was cytotoxicity and apoptosis-induced concentration with paclitaxel in HeLa cell. A half-maximal inhibition of cell proliferation ($IC_{50}$) occurred at 13 nM paclitaxel. When DNA fragmentation was analyzed by agarose gel electrophoresis, a nucleosomal ladder became evident 24 h after a taxol (50 nM) addition to the cells. In addition, an apoptotic body was detected by electron microscopy. Taxol-treated cells were arrested at the S phase at 10 nM. Treatment of 50 nM taxol activated the extracellular signal-regulated protein kinase (ERK1), and a fraction of the activated MAP kinases entered the nucleus. It was also discovered that nucleus substrates c-jun was phosphorylated and activated in the cell. The activated ERK1 could subsequently translocate into the nucleus and phosphorylate its substrate c-jun as well. This study suggests that taxol-induced apoptosis might be related with signal transduction via MAP kinases.

• BMB Reports
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• v.49 no.7
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• pp.370-375
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• 2016

Ras oncoproteins are small molecular weight GTPases known for their involvement in oncogenesis, which operate in a complex signaling network with multiple effectors. Approximately 25% of human tumors possess mutations in a member of this family. The Raf1/MEK/Erk1/2 pathway is one of the most intensively studied signaling mechanisms. Different levels of regulation account for the inactivation of MAP kinases by MAPK phosphatases in a cell type- and stimuli-dependent manner. In the present study, using three inducible Ras-expressing NIH/3T3 cell lines, we demonstrated that MKP3 upregulation requires the activation of the Erk1/2 pathway, which correlates with the shutdown of this pathway. We also demonstrated, by applying pharmacological inhibitors and effector mutants of Ras, that induction of MKP3 at the protein level is positively regulated by the oncogenic Ras/Raf/MEK/Erk1/2 signaling pathway.

• Molecules and Cells
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• v.25 no.1
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• pp.43-49
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• 2008

Cancer Osaka thyroid, also known as Tpl-2 (Cot) is a member of the MAP3K kinase family and plays a key role in the regulation of the immune response to pro-inflammatory stimuli such as lipopolysaccharide (LPS) and tumour necrosis $factor-{\alpha}$ ($TNF-{\alpha}$). A series of Cot constructs with an N-terminal 6xHis tag were transiently expressed in HEK293 cells: $Cot_{130-399}$ (kinase domain), $Cot_{1-388}$ (N-terminal and kinase do-mains), $Cot_{1-413}$, $Cot_{1-438}$ (containing a putative PEST sequence), $Cot_{1-457}$ (containing both PEST and degron sequences) and $Cot_{1-467}$ (full-length protein). These Cot proteins were pulled down using an anti-6xHis antibody and separated by 2D electrophoresis. The gels were silver-stained and 21 proteins were detected that did not appear, or had substantially reduced intensity, in the control sample. Three of these were identified by MS and MS/MS analysis as Hsp90, Hsp70 and Grp78. Hsp90 appeared to bind to the kinase domain of Cot and this interaction was further investigated using co-immuno-precipitation with both overexpressed Cot in HEK293 cells and endogenous Cot in Hela cells.

• IMMUNE NETWORK
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• v.6 no.3
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• pp.123-127
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• 2006

Background: Caveolin-1 is a principal component of caveolae membranes in vivo. Although expression of caveolae structure and expression of caveolin family, caveolin-1, -2 and -3, was known in chondrocytes, the functional role of caveolae and caveolins in chondrocytes remains unknown. In this study, we investigated the role of caveolin-1 in articular chondrocytes. Methods: Rabbit articular chondrocytes were prepared from cartilage slices of 2-week-old New Zealand white rabbits by enzymatic digestion. Caveolin-1 cDNA was transfected to articular chondrocytes using LipofectaminePLUS. The cyclooxygenase-2 (COX-2) expression levels were determined by immunoblot analysis, immunostaining, immunohistochemistry, and prostaglandin $E_2\;(PGE_2)$ assay was used to measure the COX-2 activity. Results: Ectopic expression of caveolin-1 induced COX-2 expression and activity, as indicated by immunoblot analysis and $PGE_2$ assay. And also, overexpression of caveolin-1 stimulated activation of p38 kinase and ERK-1/-2. Inhibition of p38 kinase and ERK-1/-2 with SB203580 and PD98059, respectively, led to a dose-dependent decrease COX-2 expression and $PGE_2$ production in caveolin-1-transfected cells. Conclusion: Taken together, our data suggest that ectopic expression of caveolin-1 contributes to the expression and activity of COX-2 in articular chondrocytes through MAP kinase pathway.

• Journal of Acupuncture Research
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• v.21 no.3
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• pp.107-119
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• 2004

Objective : The purpose of this study was to investigate the effect of Bee Venom and melittin on the lipopolysaccharide(LPS) and sodium nitroprusside(SNP)-induced expressions of Cell viability, nitric oxide(NO), inducible nitric oxide synthase(iNOS), extra-signal response kinase(ERK), jun N-terminal Kinase(JNK) and p38 kinase(p38)- mitogen activated protein kinase(MAPK) Family- in RAW 264.7 cells, a murine macrophage cell line. Methods : The expressions of cell viability by MTT assay, NO by Nitrite assay and iNOS, ERK, JNK and p38 were determined by Western blotting. Results : 1. Compared with the control group, 0.5, 1, $5{\mu}g/m{\ell}$ bee venom and 5, $10{\mu}g/m{\ell}$ melittin increased cell viability of RAW 264.7 induced by LPS and SNP significantly respectively. 2. Compared with the control group, 0.5, 1, $5{\mu}g/m{\ell}$ bee venom and 5, $10{\mu}g/m{\ell}$ melittin inhibited expression of NO induced by LPS and SNP significantly respectively. 3. Compared with the control group, 1, $5{\mu}g/m{\ell}$ bee venom and 5, $10{\mu}g/m{\ell}$ melittin inhibited expression of iNOS induced by LPS significantly and 0.5, 1, $5{\mu}g/m{\ell}$ bee venom and 5, $10{\mu}g/m{\ell}$ melittin inhibited expression of iNOS induced by SNP significantly. 4. Compared with the control group, the expression of ERK induced by LPS and SNP decreased significantly in the treatment groups of $5{\mu}g/m{\ell}$ bee venom and 5, $10{\mu}g/m{\ell}$ melittin, which of p-ERK by LPS also did in 1, $5{\mu}g/m{\ell}$ bee venom and 5, $10{\mu}g/m{\ell}$ melittin, but which of p-ERK by SNP did not decrease. 5. Compared with the control group, the. expression of JNK induced by LPS and SNP decreased significantly in the treatment groups of 5, $10{\mu}g/m{\ell}$ melittin, which of p-JNK by LPS in 5, $10{\mu}g/m{\ell}$ melittin and by SNP in $1{\mu}g/m{\ell}$ bee venom and $10{\mu}g/m{\ell}$ melittin decreased significantly. 6. Compared with the control group, the expression of p38 induced by LPS did not have significant difference, which induced by SNP decreased significantly in the treatment groups of 1, $5{\mu}g/m{\ell}$ bee venom and 5, $10{\mu}g/m{\ell}$ melittin. p-p38 induced by LPS decreased significantly in the treatment group of $10{\mu}g/m{\ell}$ of melittin, which induced by SNP also decreased significantly in 0.5, 1, $5{\mu}g/m{\ell}$ bee venom and 5, $10{\mu}g/m{\ell}$ melittin.

• Journal of Integrative Natural Science
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• v.10 no.2
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• pp.85-94
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• 2017

Fibroblast growth factor receptor (FGFR) belongs to the family of receptor tyrosine kinase. They play important roles in cell proliferation, differentiation, development, migration, survival, wound healing, haematopoiesis and tumorigenesis. FGFRs are reported to cause several types of cancers in humans which make it an important drug target. In the current study, HQSAR analysis was performed on a series of recently reported 1H-Pyrazolo [3,4-b]pyridine derivatives as FGFR antagonists. The model was developed with Atom (A) and bond (B) connection (C), chirality (Ch), hydrogen (H) and donor/acceptor (DA) parameters and with different set of atom counts to improve the model. A reasonable HQSAR model ($q^2=0.701$, SDEP=0.654, NOC=5, $r^2=0.926$, SEE=0.325, BHL=71) was generated which showed good predictive ability. The contribution map depicted the atom contribution in inhibitory effect. A contribution map for the most active compound (compound 24) indicated that hydrogen and nitrogen atoms in the side chains of ring B as well as hydrogen atoms in the side chain of ring C and the nitrogen atom in the ring D contributed positively to the activity in inhibitory effect whereas, the lowest active compound (compound 04) showed negative contribution to inhibitory effect. Thus results of our study can provide insights in the designing potent and selective FGFR kinase inhibitors.

• Journal of Integrative Natural Science
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• v.8 no.4
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• pp.285-292
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• 2015

LIM kinases belong to the serine/Threonine kinase family. The members of the LIM kinase (LIMK) family include LIMK 1 and 2 which are involved in the regulation of actin polymerisation and microtubule disassembly. LIMK1 was shown to be involved in cancer metastasis, while LIMK2 activation promotes cells cycle progression. Since LIMK2 plays a vital role in many disease conditions such as pulmonary hypertension, cancer and viral diseases, and till date there are not much selective inhibitors been reported, LIMK2 becomes an interesting therapeutic target among the kinases. 3D QSAR study was carried out on a series of pyrrolopyrimidines based derivatives as LIMK2 inhibitors. A reasonable CoMFA ($q^2$=0.888; ONC=3; $r^2$=0.974) with good statistical values was developed. The developed model was validated using 1000 runs of boostrapping and was found to be predictable. The results of CoMFA contour map analysis suggested that the bulky substitution at $R_4$ and $R_5$ position are highly desirable to increase the activity. Similarly, positive substitution at $R_3$ position is also required to increase the activity. It is also noted that bulky substitution at $R_1$ position must be avoided. Our results could provide valuable information to enhance the activity of the LIMK2 inhibitors and to design potent pyrrolopyrimidines derivatives.

• BMB Reports
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• v.31 no.6
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• pp.560-564
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• 1998

Echinomycin-7 is an echinomycin derivative, Smethylated sulfonium perchlorate of echinomycin. We studied the in vitro cytotoxicity and in vivo antitumor activity of echinomycin-7 against P388 leukemia cells and compared the results with echinomycin. With respect to the cytotoxic effects, echinomycin-7 had cell line-dependent $IC_{50}$ values while echinomycin had similar values to several tumor cell lines. Also, in vivo antitumor activities were observed in tumor-bearing mice treated with both agents, which showed that echinomycin-7 had a broad therapeutic dose range. We also observed the apoptosis on leukemia cells treated with echinomycin-7 which exihibited the ladder pattern of DNA on electrophoresis. In addition to apoptosis, echinomycin-7 arrested $G_1/S$ phases of the cell cycle at the same time. We then examined the signaling pathway of echinomycin-7-induced apoptosis and showed that ERK of the MAP kinase family was activated and translocated into the nucleus by echinomycin-7 stimulation. This study suggests that echinomycin-7 acts as an antitumor agent through in vitro cytotoxicity and has in vivo antitumor activity against leukemia cells, and that the echinomycin-7- induced apoptosis might involve signal transduction via MAP kinases.