Physicians play a central role in the fields of medical service, research, and industry, so it is imperative to produce well-qualified doctors. Medicine is composed of science and arts, both necessary for its practice, and thus, the education outcomes in basic medical education in a medical school include basic biomedical sciences, social sciences and clinical sciences. Adequate science competencies create a deeper and better understanding of scientific knowledge, concepts, and methods fundamental to clinical science, and contribute to the scientific, technological, and clinical developments. The science competencies are primarily obtained by studying basic medicine in basic medical education, which has been criticized for failing to do so sufficiently in Korea. The failure is attributed to insufficient education time, teachers, and budgets, but the most critical factor is the lack of awareness regarding the importance of the science competencies of the physicians. Such ignorance also affects the Korean Medical Licensing Examination (KMLE). The KMLE tests competency in clinical sciences, preventive medicine, and medical laws, but not in basic biomedical sciences, which might result in insufficient science competency of the physicians and a decrease in the overall quality of the medical health service. Tests must be urgently introduced in KMLE on the competencies of basic biomedical sciences to improve the science competency of the physicians. The representative organizations of the medical society should take vigorous actions for the introduction of the basic medicine examination in KMLE.
Budgets ; Education ; Education, Medical ; Fibrinogen ; Health Services ; Jurisprudence ; Korea ; Licensure ; Preventive Medicine ; Schools, Medical ; Social Sciences ; Societies, Medical

Physicians play a central role in the fields of medical service, research, and industry, so it is imperative to produce well-qualified doctors. Medicine is composed of science and arts, both necessary for its practice, and thus, the education outcomes in basic medical education in a medical school include basic biomedical sciences, social sciences and clinical sciences. Adequate science competencies create a deeper and better understanding of scientific knowledge, concepts, and methods fundamental to clinical science, and contribute to the scientific, technological, and clinical developments. The science competencies are primarily obtained by studying basic medicine in basic medical education, which has been criticized for failing to do so sufficiently in Korea. The failure is attributed to insufficient education time, teachers, and budgets, but the most critical factor is the lack of awareness regarding the importance of the science competencies of the physicians. Such ignorance also affects the Korean Medical Licensing Examination (KMLE). The KMLE tests competency in clinical sciences, preventive medicine, and medical laws, but not in basic biomedical sciences, which might result in insufficient science competency of the physicians and a decrease in the overall quality of the medical health service. Tests must be urgently introduced in KMLE on the competencies of basic biomedical sciences to improve the science competency of the physicians. The representative organizations of the medical society should take vigorous actions for the introduction of the basic medicine examination in KMLE.

Physicians play a central role in the fields of medical service, research, and industry, so it is imperative to produce well-qualified doctors. Medicine is composed of science and arts, both necessary for its practice, and thus, the education outcomes in basic medical education in a medical school include basic biomedical sciences, social sciences and clinical sciences. Adequate science competencies create a deeper and better understanding of scientific knowledge, concepts, and methods fundamental to clinical science, and contribute to the scientific, technological, and clinical developments. The science competencies are primarily obtained by studying basic medicine in basic medical education, which has been criticized for failing to do so sufficiently in Korea. The failure is attributed to insufficient education time, teachers, and budgets, but the most critical factor is the lack of awareness regarding the importance of the science competencies of the physicians. Such ignorance also affects the Korean Medical Licensing Examination (KMLE). The KMLE tests competency in clinical sciences, preventive medicine, and medical laws, but not in basic biomedical sciences, which might result in insufficient science competency of the physicians and a decrease in the overall quality of the medical health service. Tests must be urgently introduced in KMLE on the competencies of basic biomedical sciences to improve the science competency of the physicians. The representative organizations of the medical society should take vigorous actions for the introduction of the basic medicine examination in KMLE.

This study was performed to investigate the signaling pathway that mediates cyclic AMP (cAMP)-induced inhibition of histone deacetylase 8 (HDAC8) degradation, and the effect and underlying mechanisms of the resulting increase in HDAC8 expression on cisplatin-induced apoptosis in lung cancer cells. cAMP signaling increased HDAC8 expression via a protein kinase A (PKA)-independent pathway in H1299 non-small cell lung cancer cells. However, treatment with a selective activator of an exchange protein that was activated by cAMP (Epac) increased HDAC8 expression, and Epac2 inhibition abolished the isoproterenol (ISO)-induced increase in HDAC8 expression. ISO and the Epac activator activated Rap1, and Rap1A activation increased HDAC8 expression; moreover, inhibition of Rap1A with a dominant negative Rap1A or by shRNA-mediated knockdown abolished the ISO-induced increase in HDAC8 expression. Activation of cAMP signaling and Rap1A decreased the activating phosphorylation of Akt. Akt inhibition with a pharmacological inhibitor or expression of a dominant negative Akt inhibited the MKK4/JNK pathway and increased HDAC8 expression. The Akt inhibitor-induced increase in HDAC8 expression was abolished by pretreatment with proteasomal or lysosomal inhibitors. The ISO treatment increased cisplatin-induced apoptosis, which was abolished by HDAC8 knockdown. Exogenous HDAC8 expression increased cisplatin-induced apoptosis and decreased TIPRL expression, and the knockdown of TIPRL increased the apoptosis of cisplatin-treated cells. The ISO treatment decreased cisplatin-induced transcription of the TIPRL gene in a HDAC8-dependent manner. In conclusion, the Epac–Rap1–Akt pathway mediates cAMP signaling-induced inhibition of JNK-dependent HDAC8 degradation, and the resulting HDAC8 increase augments cisplatin-induced apoptosis by repressing TIPRL expression in H1299 lung cancer cells.
Apoptosis ; Carcinoma, Non-Small-Cell Lung ; Cyclic AMP ; Cyclic AMP-Dependent Protein Kinases ; Histone Deacetylases* ; Histones* ; Isoproterenol ; Lung Neoplasms* ; Lung* ; Phosphorylation

Stress conditions are correlated with tumor growth, progression and metastasis. We hypothesized that stress signals might affect tumor progression via epigenetic control of gene expression and investigated the effects of stress signals on the expression levels of histone deacetylases (HDACs) and the underlying mechanisms of these effects in lung cancer cells. Treatment with isoproterenol (ISO), an analog of the stress signal epinephrine, increased the expression of HDAC6 protein and mRNA in H1299 lung cancer cells. ISO caused the deacetylation of α-tubulin and stimulated cell migration in an HDAC6-dependent manner. HDAC6 expression was increased by treatment with selective activators of cAMP-dependent protein kinase (PKA) or exchange protein activated by cAMP (Epac). ISO activated Rap1 via Epac, and constitutively active Rap1A increased the HDAC6 level; however, the knockdown of Rap1A decreased the 8-(4-cholorophenylthio)-2′-O-methyl-cAMP-induced increase in HDAC6 expression. Both PKA and Rap1A decreased c-Raf activation to inhibit extracellular signal-regulated kinase (ERK) signaling. Inhibition of ERK caused an increase in HDAC6 expression, and constitutively active MEK1 decreased the ISO-induced HDAC6 expression. We concluded that ISO increases HDAC6 expression via a PKA/Epac/ERK-dependent pathway that stimulates the migration of lung cancer cells. This study suggests that stress signals can stimulate the migration of cancer cells by inducing HDAC6 expression in lung cancer cells.
Cell Movement* ; Cyclic AMP-Dependent Protein Kinases ; Epigenomics ; Epinephrine ; Gene Expression ; Histone Deacetylases* ; Histones* ; Humans* ; Isoproterenol* ; Lung Neoplasms* ; Lung* ; Neoplasm Metastasis ; Phosphotransferases ; RNA, Messenger

Heterotrimeric GTP-binding proteins (G protein) are known to participate in the transduction of signals from ligand activated receptors to effector molecules to elicit cellular responses. Sustained activation of cAMP-G protein signaling system by agonist results in desensitization of the pathway at receptor levels, however it is not clear whether such receptor responses induce other changes in post-receptor signaling path that are associated with maintenance of AMP levels, i.e. cAMP-forming adenylate cyclase (AC), cAMP-degrading cyclic nucleotide phosphodiesterase (PDE) and cAMP-dependent protein kinase (PKA). Experiments were performed to determine the expression of AC, PDE, and PKA isoforms in SH-SY5Y neuroblastoma cells, in which cAMP system was activated by expressing a constitutively activated mutant of stimulatory G protein (Q227L Gsalpha). Expression of ACI mRNA was increased, but levels of ACVIII and ACIX mRNA were decreased. All of the 4 expressed isoforms of PDE (PDE1C, PDE2, PDE 4A, and PDE4B) were increased in mRNA expression; the levels of PKA RIalpha, RIbeta, and RIIbeta were increased moderately, however, those of RIIalpha and Calpha were increased remarkably. The activities of AC, PDE and PKA were also increased in the SH-SY5Y cells expressing Q227L Gsalpha. The similar changes in expression and activity of AC, PDE and PKA were observed in the SH-SY5Y cells treated with dbcAMP for 6 days. Consequently, it is concluded that the cAMP system adapts at the post-receptor level to a sustained activation of the system by differential expression of the isoforms of AC, PDE, and PKA in SH-SY5Y neuroblastoma. We also showed that an increase in cellular cAMP concentration might mediate the observed changes in the cAMP system.
3',5'-Cyclic-Nucleotide Phosphodiesterase/genetics/metabolism ; Adenylate Cyclase/genetics/metabolism ; Cyclic AMP/*metabolism ; Cyclic AMP-Dependent Protein Kinases/genetics/metabolism ; G-Protein, Stimulatory Gs/genetics/metabolism ; Heterotrimeric GTP-Binding Proteins/genetics/*metabolism ; Human ; Isoenzymes ; Isoproterenol/pharmacology ; Mutation ; Neuroblastoma/*metabolism ; *Signal Transduction ; Support, Non-U.S. Gov't ; Tumor Cells, Cultured

The growth factor receptor oncogene, c-erb B-2, is frequently overexpressed in the adenocarcinomas of breast, ovary, lung and stomach. Although the mechanism of erb B-2 overexpression is thought as the result of transcriptional upregulation in many primary human carcinomas, expression rate of c-erb B-2 at mRNA level is usually lower than the level of translated protein. We also found that the expression of erb B-2 in SNU-1 stomach cancer cells was greater at post-transcription level (Bae et al., 1993). To explore the underlying mechanism of erb B-2 protein overexpression, we have chosen two cells lines, SNU-1 and SNU-16 where transcription rate of erb B-2 was closely resemble to each other while expressed protein levels were quite different. The synthesis rate of erb B-2 protein in SNU-1 cells was faster than SNU-16 cells while levels of erb B-2 mRNA were found to be similar in both cell lines. The half-life of the expressed erb B-2 protein was not significantly different in both cell lines. Analysis of the 5' untranslated region (UTR) of erb B-2 mRNA (-1approximately-323) showed no sequence abnormality in both cell lines. However, ribonuclease protection assay using cloned 5 UTR sequence revealed that the size of 5' UTR of erb B-2 mRNA which associate with transcription initiation site(s) in SNU-1 cells was longer than that in SNU-16. These results suggest that the increased erb B-2 protein synthesis rate possibly due to the redundant selection of transcription initiation might be a mechanism of erb B-2 overexpression in SNU-1 cells.
5' Untranslated Regions ; Base Sequence ; Comparative Study ; Gene Expression Regulation, Neoplastic ; Half-Life ; Human ; Molecular Sequence Data ; Protein Processing, Post-Translational ; Receptor, erbB-2/*genetics/*metabolism ; Stomach Neoplasms/genetics/*metabolism ; Support, Non-U.S. Gov't ; Transcription, Genetic ; Tumor Cells, Cultured

The terminal differentiation of malignant melanoma cells is known to be induced by activating cAMP signaling pathway with alpha-MSH or cAMP analogues. However, sustained activation of cAMP signaling system that induces the differentiation of melanoma cells, also induces the desensitization of the pathway at the receptor level. Nevertheless, the adaptation of adenylate cyclase (AC) expression by sustained activation of cAMP signaling system has not been clearly understood. This study was performed to examine whether the sustained activation of cAMP system induce changes in the expression AC isoforms as an adaptation mechanism. Treatment of B16/F10 murine melanoma cells with 100 mM forskolin for 6 days resulted in differentiation, melanin accumulation and increased expression of tyrosine hydroxylase mRNA. In the forskolin-treated melanoma cells, change in expression of various AC isoform at the transcription level was detected by reverse-transcription polymerase chain reaction (RT-PCR). Expression of AC isoform mRNA: ACI, III, VI, VII, and IX increased to the level of 196-392% of the control whereas the level of ACII was decreased by 30%. The cAMP concentration was increased both in basal and alpha-MSH stimulated cells, but the AC activity was decreased in the forskolin treated cells. Thus, these results suggest that sustained activation of cAMP system induces differential expression of AC isoforms, which results in increase of cAMP accumulation.
Adenylate Cyclase/*genetics ; Animal ; Cell Differentiation ; Cyclic AMP/*metabolism ; Forskolin/*pharmacology ; Isoenzymes/genetics ; Melanoma, Experimental/*enzymology/*pathology ; Mice ; Signal Transduction

Heterotrimeric GTP-binding proteins (G proteins) transduce extracellular signals into intracellular signals by activating effector molecules including adenylate cyclases that catalyze cAMP formation, and thus regulate various cellular responses such as metabolism, proliferation, and apoptosis. cAMP signaling pathways have been reported to protect cells from ionizing radiation-induced apoptosis, but however, the protective mechanism is not clear. Therefore, this study aimed to investigate the signaling molecules and the mechanism mediating the anti-apoptotic action of cAMP signaling system in radiation-induced apoptosis. Stable expression of a constitutively active mutant of G alpha s (G alpha sQL) protected gamma ray-induced apoptosis which was assessed by analysis of the cleavages of PARP, caspase-9, and caspase-3 and cytochrome C release in SH-SY5Y human neuroblastoma cells. G alpha sQL repressed the gamma ray-induced down-regulation of Bcl-xL protein, but transfection of Bcl-xL siRNA increased the gamma ray-induced apoptosis and abolished the anti-apoptotic effect of G alpha sQL. G alpha sQL decreased the degradation rate of Bcl-xL protein, and it also restrained the decrease in Bcl-xL mRNA by increasing the stability following ionizing irradiation. Furthermore, prostaglandin E2 that activates G alpha s was found to protect gamma ray-induced apoptosis, and the protective effect was abolished by treatment with prostanoid receptor antagonist specific to EP2/4R subtype. Moreover, specific agonists for adenosine A1 receptor that inhibits cAMP signaling pathway augmented gamma ray-induced apoptosis. From this study, it is concluded that Galphas-cAMP signaling system can protect SH-SY5Y cells from gamma ray-induced apoptosis partly by restraining down-regulation of Bcl-xL expression, suggesting that radiation-induced apoptosis can be modulated by GPCR ligands to improve the efficiency of radiation therapy.
Apoptosis/*physiology/*radiation effects ; Base Sequence ; Cell Line, Tumor ; Cyclic AMP/metabolism ; DNA Primers/genetics ; Down-Regulation/radiation effects ; GTP-Binding Protein alpha Subunits, Gs/*metabolism ; Gamma Rays ; Humans ; Neuroblastoma/genetics/metabolism/pathology ; RNA, Small Interfering/genetics ; Signal Transduction ; bcl-X Protein/genetics/*metabolism

Stimulatory heterotrimeric GTP-binding proteins (Gs protein) stimulate cAMP generation in response to various signals, and modulate various cellular phenomena such as proliferation and apoptosis. This study aimed to investigate the effect of Gs proteins on gamma ray-induced apoptosis of lung cancer cells and its molecular mechanism, as an attempt to develop a new strategy to improve the therapeutic efficacy of gamma radiation. Expression of constitutively active mutant of the alpha subunit of Gs (GalphasQL) augmented gamma ray-induced apoptosis via mitochondrial dependent pathway when assessed by clonogenic assay, FACS analysis of PI stained cells, and western blot analysis of the cytoplasmic translocation of cytochrome C and the cleavage of caspase-3 and ploy(ADP-ribose) polymerase (PARP) in H1299 human lung cancer cells. GalphasQL up-regulated the Bak expression at the levels of protein and mRNA. Treatment with inhibitors of PKA (H89), SP600125 (JNK inhibitor), and a CRE-decoy blocked GalphasQL-stimulated Bak reporter luciferase activity. Expression of GalphasQL increased basal and gamma ray-induced luciferase activity of cAMP response element binding protein (CREB) and AP-1, and the binding of CREB and AP-1 to Bak promoter. Furthermore, prostaglandin E2, a Galphas activating signal, was found to augment gamma ray-induced apoptosis, which was abolished by treatment with a prostanoid receptor antagonist. These results indicate that Galphas augments gamma ray-induced apoptosis by up-regulation of Bak expression via CREB and AP-1 in H1299 lung cancer cells, suggesting that the efficacy of radiotherapy of lung cancer may be improved by modulating Gs signaling pathway.
Apoptosis/*radiation effects ; Cell Line, Tumor ; Cyclic AMP Response Element-Binding Protein/metabolism ; GTP-Binding Protein alpha Subunits, Gs/*metabolism ; *Gamma Rays ; Heterotrimeric GTP-Binding Proteins/metabolism ; Humans ; Lung/*cytology/physiology/radiation effects ; Lung Neoplasms ; Transcription Factor AP-1/metabolism ; *Up-Regulation ; bcl-2 Homologous Antagonist-Killer Protein/*metabolism