• Radiation Oncology Journal
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• v.25 no.4
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• pp.233-241
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• 2007

Purpose: We examined the effect of the dual EGFR/HER2 tyrosine kinase inhibitor, GW572016, on EGFR/HER2 receptor phosphorylation, inhibition of downstream signaling and radiosensitization in either an EGFR or HER2 overexpressing human breast cancer xenograft. Materials and Methods: We established SCID mice xenografts from 4 human breast cancer cell line that overexpressed EGFR or HER 2 (SUM 102, SUM 149, SUM 185, SUM 225). Two series of xenografts were established. One series was established for determining inhibition of the EGFR/HER2 receptor and downstream signaling activities by GW572016. The other series was established for determining the radiosensitization effect of GW572016. Inhibition of the receptor and downstream signaling proteins were measured by the use of immunoprecipitation and Western blotting. For determining the in vivo radiosensitization effect of GW572016, we compared tumor growth delay curves in the following four treatment arms: a) control; b) GW572016 alone; c) radiotherapy (RT) alone; d) GW572016 and RT. Results: GW572016 inhibited EGFR, HER2 receptor phosphorylation in SUM 149 and SUM 185 xenografts. In addition, the p44/42 MAPK (ERK 1/2) downstream signaling pathway was inactivated by GW572016 in the SUM 185 xenograft. In the SUM 225 xenograft, we could not observe inhibition of HER2 receptor phosphorylation by GW572016; both p44/42 MAPK (Erk1/2) and Akt downstream signal protein phosphorylation were inhibited by GW572016. GW572016 inhibited growth of the tumor xenograft of SUM 149 and SUM 185. The combination of GW572016 and RT enhanced growth inhibition greater than that with GW572016 alone or with RT alone in the SUM 149 xenograft. GW572016 appears to act as an in vivo radiosensitizer. Conclusion: GW572016 inhibited EGFR/HER2 receptor phosphorylation and downstream signaling pathway proteins. GW572016 modestly inhibited the growth of tumor in the SUM 185 xenograft and showed radiosensitization in the SUM 149 xenograft. Our results suggest that a better predictor of radiation response would be inhibition of a crucial signaling pathway than inhibition of a receptor.

• Biomolecules & Therapeutics
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• v.20 no.1
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• pp.43-49
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• 2012

Stimulation of mast cells through the high affinity IgE receptor (Fc${\varepsilon}$RI) induces degranulation, lipid mediator release, and cytokine secretion leading to allergic reactions. Although various signaling pathways have been characterized to be involved in the Fc${\varepsilon}$RI-mediated responses, little is known about the precious mechanism for the expression of tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) in mast cells. Here, we report that rapamycin, a specific inhibitor of mammalian target of rapamycin (mTOR), reduces the expression of TNF-${\alpha}$ in rat basophilic leukemia (RBL-2H3) cells. IgE or specific antigen stimulation of RBL-2H3 cells increases the expression of TNF-${\alpha}$ and activates various signaling molecules including S6K1, Akt and p38 MAPK. Rapamycin specifically inhibits antigeninduced TNF-${\alpha}$ mRNA level, while other kinase inhibitors have no effect on TNF-${\alpha}$ mRNA level. These data indicate that mTOR signaling pathway is the main regulation mechanism for antigen-induced TNF-${\alpha}$ expression. TNF-${\alpha}$ mRNA stability analysis using reporter construct containing TNF-${\alpha}$ adenylate/uridylate-rich elements (AREs) shows that rapamycin destabilizes TNF-${\alpha}$ mRNA via regulating the AU-rich element of TNF-${\alpha}$ mRNA. The antigen-induced activation of S6K1 is inhibited by specific kinase inhibitors including mTOR, PI3K, PKC and $Ca^{2+}$chelator inhibitor, while TNF-${\alpha}$ mRNA level is reduced only by rapamycin treatment. These data suggest that the effects of rapamycin on the expression of TNF-${\alpha}$ mRNA are not mediated by S6K1 but regulated by mTOR. Taken together, our results reveal that mTOR signaling pathway is a novel regulation mechanism for antigen-induced TNF-${\alpha}$ expression in RBL-2H3 cells.

• Korean Journal of Veterinary Research
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• v.30 no.2
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• pp.163-170
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• 1990

The blood chemical values and blood enzyme activities were examined from 74 healthy mixed breed dogs in the area of Seoul. The results obtained are summarized as follows; 1. Mean${\pm}$SD values and ranges of glucose were $61.97{\pm}8.41mg/100ml$ and 47.28~81.67mg/100ml, of blood urea nitrogen(BUN) $15.99{\pm}2.31mg/100ml$ and 8.21~21.31mg/100ml, of total protein(TP) $8.17{\pm}0.93g/100ml$ and 6.06~9.91g/100ml, of albumin $4.16{\pm}0.47g/100ml$ and 2.81~5.15g/100ml, of globulin, $4.01{\pm}0.64g/100ml$ and 2.72~5.54g/100ml, of albumin/globulin(A/G) ratio $1.06{\pm}0.17$ and 0.71~1.42, of cholesterol(Chol) $187.33{\pm}19.78mg/100ml$ and 128.70~222.90mg/100ml, of total bilirubin(TB) $0.73{\pm}0.14mg/100ml$ and 0.43~1.16mg/100ml, of phosphorus(Pi) $5.25{\pm}1.00mg/100ml$ and 2.61~7.72mg/100ml, of calcium(Ca) $10.76{\pm}1.08mg/100ml$ and 8.24~12.60mg/100ml, of triglyceride(TG) $89.48{\pm}21.16mg/100ml$ and 47.80~133.00mg/100ml, respectively. 2. The glucose value in the age group of 7~12 months was higher (p<0.01) but in the age group of 3~4 years was lower (p<0.05) than the total glucose value. The TP value in the age group of 7~12 months was lower (p<0.01) but in the age group of 1~2 years was higher (p<0.05) than the total TP value. The globulin value in the age group of 7~12 months was lower (p<0.01) but in the group of 1~2 years was higher (p<0.01) than the total globulin value. The A/G ratio value in the age group of 7~12 months was higher (p<0.05) but in the age group of 1~2 years was lower (p<0.05) than the total A/G ratio value. The phosphorus values in the age group of 1~2 years and the age group of 3~4 years were lower (p<0.01, p<0.001) than the total phosphorus value. The calcium value in the age group of less than 6 months was higher (p<0.05) but in the age group of 7~12 months was lower (p<0.001) than the total calcium value. 3. Mean${\pm}$S.D. values and ranges of alkaline phosphatase(AP) were $72.47{\pm}19.73IU/l$, and 28.13~105.00IU/l, of lactic dehydrogense(LDH) $159.46{\pm}45.11IU/l$ and 60.63~265.30IU/l, of serum aspartate aminotransferase(AST) $38.64{\pm}8.62IU/l$ and 21.47~70.58IU/l, of serum alanine aminotransferase(ALT) $34.88{\pm}11.30IU/l$ and 14.51~73.17IU/l, respectively. 4. The AP value in the age group of 7~12 months was higher (p<0.05) but in the age group of 1~2 years was lower (p<0.01, p<0.001) than the total AP value. The LDH value in the age group of less than 6 months was higher (p<0.001) but in the age group of 1~2 years and the age group of 3~4 years were lower (p<0.05) than the total LDH value. The serum AST value in the age group of 3~4 years was lower (p<0.01) than the total SGOT value. The serum ALT value in the age group of 7~12 months was higher(p<0.05) than the total SGPT value.