Changes in Somatostatin Receptor mRNA Levels by G Protein Mutation in GH3 Cells Which Show Responsiveness to Growth Hormone-Releasing Hormone / 대한내분비학회지

BACKGROUNDS: GH3 cells lack growth hormone(GH)-releasing hormone(GHRH) receptors. In this study, GH3 cells permanently transfected with human GHRH receptor cDNA(GH3-GHRHR cells), were established in order to examine the effects of GHRH and G protein mutation(gsp oncogene) on the levels of somatostatin receptor mRNA. METHODS: GH3 cells were permanently transfected with a plasmid expressing human GHRH receptor cDNA. The GHRH receptor mRNA was detected by RT-PCR. The responsiveness to GHRH was evaluated using a GHRH binding assay, Western blot analysis, Northern blot analysis, and measurements of the intracellular cAMP levels and GH release. Cells were transiently transfected with the gsp oncogene, and then treated with GHRH or octreotide for 4h. The sst1 and sst2 mRNA levels were measured using real-time RT-PCR analyses. RESULTS: GHRH receptor mRNA was detected in the GH3 cells permanently transfected with human GHRH receptor cDNA. The GHRH binding assay showed that GHRH was bound to the GH3-GHRHR cells. The GHRH treatment increased the intracellular cAMP levels, GH release, GH mRNA levels, and MAPK activity, as well as the levels of sst1 and sst2 mRNA. Transient expression of the gsp oncogene for 48h increased the cAMP, GH release, and levels of sst1 and sst2 mRNA. In the gsp-transfected GH3-GHRHR cells, GHRH stimulation resulted in decreases in the magnitude of the increase in the levels of sst1 and sst2 mRNA compared to those transfected with a control vector. Octreotide treatment did not alter the levels of sst1 and sst2 mRNA in either the control or gsp-transfected cells. CONCLUSION: These results suggest that GH3 cells permanently transfected with the GHRH receptor are useful in the in vitro studies on the actions of GHRH. The gsp oncogene was shown to increases the levels of sst1 and sst2 mRNA in GH3 cells, but these findings are unlikely to be the major mechanism by which gsp-positive pituitary tumors show a greater response to somatostatin. The discrepancy between the in vivo and these in vitro results should be examined further.

Selective Cytotoxicity of Novel Platinum (II) Coordination Complexes on Human Bladder Cancer Cell-Lines and Normal Kidney Cells

Cisplatin is often effective in cancer treatment, but its clinical use is limited because of its nephrotoxicity. We have synthesized new platinum (II) coordination complexes (PC-1 & PC-2) containing trans-l and cis-1, 2-diaminocyclohexane (DACH) as carrier ligands and L-3 -phenyllactic acid (PLA) as a leaving group with the aim of reducing nephrotoxicity but maintaining its anticancer activity. In this study, new platinum (II) complex compounds were evaluated for selective cytotoxicity on cancer cell-lines and normal kidney cells. The new platinum complexes have demonstrated high efficacy in the cytotoxicity against human bladder carcinoma cell-lines (T-24/HT-1376). The cytotoxicity of these compounds against rabbit proximal renal tubular cells and human renal cortical tissues, was determined by MTT assay, the [3H]-thymidine uptake and glucose consumption test, and found to be quite less than those of cisplatin. Based on our results, these novel platinum compounds appear to be valuable lead compounds with high efficacy and low nephrotoxicity.

Assessment of an Apo-1/Fas Promoter Polymorphism in Korean Schizophrenia Patients

Apoptosis has been hypothesized to be involved in the pathogenesis in schizophrenia. A large number of genes are known to mediate the apoptotic process; Apo-1/Fas (CD95) is a well-known example of such genes. In the present study, MvaI restriction fragment length polymorphism, a polymorphic marker present within the Apo-1/Fas gene, was examined in a population consisting of 226 control subjects and 110 schizophrenia patients, all of them Korean in ethnicity. No statistically significant difference in the genotypic distribution and allelic frequencies was observed between the control and the schizophrenia patient group. To find out the precise effect of Apo-1/Fas gene polymorphisms on the susceptibility to schizophrenia, further studies are warranted to investigate possible involvement of other polymorphisms with a larger sample population.

In vitro cytotoxicity of a novel platinum(II) coordination complex containing diaminocyclohexane and dichloropropane

We have synthesized a novel platinum(II) coordination complex containing cis-1,2-diaminocyclohexane (DACH) as a carrier ligand and 1,3-dichloropropane (DCP) as a leaving group. A new series of (Pt(cis-DACH)(DCP))(PC) was evaluated for its cytotoxic: activity on MKN-45 human gastric adenocarcinoma cells and normal primary cultured kidney cells. The new platinum complex has demonstrated high efficacy in the cytotoxicity against MKN-45/P, MKN-45/ADM and MKN-45/CDDP cell-lines. The cytotoxicity of PC against rabbit proximal renal tubular cells, human renal cortical cells and human renal cortical tissues, determined by MTT assay, the (3H)-thymidine uptake and glucose consumption tests, was found to be quite less than those of cisplatin. Based on these results, this novel platinum(II) coordination complex appears to be better for improving antitumor activities with low nephrotoxicity and is a valuable lead in the development of new, clinically available anticancer chemotherapeutic agents.

Indomethacin induces apoptosis in NCI-H1299 human lung carcinoma cells

Recently, nonsteroidal anti-inflammatory drugs (NSAIDs) have been found to be useful in the chemoprevention of colon cancer. To investigate whether indomethacin, an NSAIDs, induces apoptosis and thus assess the possibility of its application in the chemoprevention of human lung cancer, we have performed MTT assay, TUNEL assay, DAPI staining, and flow cytometric analysis using human lung carcinoma cell line NCI-H1299. Through morphological and biochemical analyses, it was demonstrated that NCI-H1299 cells treated with indomethacin (0.5 mM) exhibit classical apoptotic features. These results suggest that indomethacin induces apoptosis in NCI-H1299 cells and that NSAIDs, including indomethacin, may be a useful tool for the chemoprevention of human lung cancer.

Thyrotropin-releasing Hormone(TRH) Receptor Gene Expression in GH3 Cells Permanently Transfected with a Mutant Gs alpha Gene / 대한내분비학회지

BACKGROUND: Gs alpha gene mutation, that constitutively increases intracellular cAMP, is found in some acromegalic patients. It was demonstrated that increased intracellular cAMP levels suppress the expression of rat TRH receptor (TRH-R) mRNA. We previously demonstrated that transient expression of a mutant Gs alpha gene suppress the rat TRH-R gene expression in the cultured rat growth hormone-secreting tumor cell line (GH3), whereas TRH-R gene expression in adenomas with Gs alpha gene mutation (gsp oncogene) did not differ from that in tumors without the mutation. The discrepancy suggests the possibilities that the effect of permanent expression of mutant Gs alpha gene on TRH-R gene expression is different from that of transient expression of the mutant gene and hypothalamic hormones including TRH regulate the gene expression. METHODS: We investigated whether permanent expression of the mutant-type Gs alpha does not suppress the TRH receptor gene expression in GH3 cells, and whether TRH suppresses the gene expression by using reverse transcription-polymerase chain reaction (RT-PCR) and in vitro transcription. RESULTS: Permanent expression of a mutant-type Gs alpha increased basal cAMP levels up to 1.7-fold relative to the controls, whereas the wild-type cell line did not show increased cAMP levels. Permanent expression of a mutant-type Gs alpha increased TRH receptor mRNA level up to 2.8 fold compared with the controls. Treatment of the permanently transfected GH3 cells with TRH suppressed TRH-R gene expression more prominently compared to the wild type GH3 cells. CONCLUSION: These results suggest that permanent expression of mutant Gs alpha enhances the expression of TRH-R in GH-secreting pituitary tumors with gsp oncogene, but the gene expression may also be regulated by other factors including TRH.

Selective cytotoxicity of a novel platinum(II) coordination complex on human bladder cancer cell lines and normal kidney cells

We have synthesized a novel platinum(II) coordination complex containing cis-1,2-diaminocyclohexane (DACH) as a carrier ligand and 1,2-dichloroethane (DCE) as a leaving group. In addition, nitrate was added to improve the water-solubility. A new series of (Pt(cis-DACH)(DCE)) cntdot 2NO3(PC) was evaluated for its cytotoxic activity on T-24 and J-82 human bladder carcinoma cells and normal primary cultured kidney cells. PC has demonstrated high levels of cytotoxicity against T-24 and J-82 cells. The cytotoxicity of PC against rabbit proximal renal tubular cells, human renal cortical cells and human renal cortical tissues, determined using the MTT assaying technique, the (3H)-thymidine uptake and glucose consumption tests, was found to be quite less than those of cisplatin. Based on these results, this novel platinum(II) coordination complex appears to be better for improving antitumor activities with low nephrotoxicity and is a valuable lead in the development of new clinically available anticancer chemotherapeutic agents.

Selective Cytotoxicity of the New Platnum ( 2 ) Complexes on Human Gastric Cancer Cell - lines and Normal Kidney Cells / 대한암학회지

PURPOSE: Platinum coordination complex (cisplatin) has been currently used as one of the most effective compound in the treatment of various solid tumors. However, its use has been limited by severe side effects such as renal toxicity. Our platinum-based drug discovery program has been aimed at developing drugs capable of diminishing toxicity and selective cytotoxicity. MATERIALS AND METHODS: A new series of highly water soluble platinum (II) complexes Pt (II) [1,3-Bis (phenylthio) propane) (trans-l-1,2-diaminocyclohexane) (PC-1) and Pt (II) [1,3-Bis-(phenylthio) (propane)]-1,2-diaminocyclohexane (PC-2) were synthesized and characterized by their elemental analysis and by various spectroscopic techniques [infrared (.IR), ""C-nuclear magnetic resonance (NMR)]. In vitro antitumor activity and nephrotoxi -cities of new Pt (II) complexes were tested against MKN-45 human gastric cancer cell- lines and normal kidney cells using colorimetric MTT[3-(4,5-dimethyl thiazol-2-yl)-2,5- diphenyl tetrazolium bromide] assay for cell survival and proliferation. RESULTS: PC-1 showed activity against MKN-45/P and MKN-45/CDDP human gastric adenocarcinoma cells, and the antitumor activity of this compound was comparable or superior to that of PC-2 and cisplatin. The nephrotoxicity of PC-1 and PC-2 were found quite less than that of cisplatin using MTT, [H] thymidine uptake and glucose consumption tests in rabbit proximal tubule cells, human kidney cortical cells and human renal cortical tissues. CONCLUSION: Based on these results, this novel platinum (II) complex compound (PC-1) represent a valuable lead in the development of a new anticancer chemotherapeutic agent capable of improving antitumor activity and low nephrotoxicity.

Selective cytotoxicity of a novel platinum (II) coordination complex on human gastric cancer cell lines and normal kidney cells

We have synthesized novel platinum (II) coordination complex containing cis-1,2-diaminocyclohexane (DACH) as a carrier ligand and 1,2-bis(diphenylphosphino)ethane (DPPE) as leaving group. Furthermore, nitrate was added to improve the water-solubility. A new series of (Pt(cis-DACH)(DPPE)) cntdot 2NO3 (PC) was evaluated its antitumor activity on various MKN-45 human gastric adenocarcinoma cell-lines and normal primary cultured kidney cells. The new platinum complex demonstrated high efficacy in the cytotoxicity on MKN-45 cell-lines as well as adriamycin-resistant (MKN-45/ADR) and cisplatin-resistant (MKN-45/CDDP) cells. The cytotoxicities of PC were found quite less than those of cisplatin in rabbit proximal renal tubular cells, human renal cortical cells and human renal cortical tissues using MTT assay, (3H)-thymidine uptake and glucose consumption tests. Based on these results, this novel platinum (II) coordination complex, was considered as better a valuable lead for improving antitumor activities with low nephrotoxicities in the development of a new clinically available anticancer chemotherapeutic agents.

Two dinucleotide repeat polymorphisms (AC/TG and GT/CA) in the 5' upstream region of the mouse tryptophan hydroxylase gene

Tryptophan hydroxylase (TPH), the rate-limiting enzyme in serotonin biosynthesis, is primarily expressed in serotonergic neurons of the raphe nuclei. Simple tandem repeat polymorphisms, typically one to four nucleotides long, are tandemly repeated several times and often characterized by many alleles. To identify the presence of polymorphic repeats, we sequenced the 5'-upstream region of the mouse TPH gene. For the detection of any allelic variants, polymerase chain reaction, nonisotopic single-strand conformation polymophism, and DNA sequencing analyses of the tandem repeat sequences were performed using genomic DNA extracted from 60 ICR mice. Two dinucleotide repeats, 5'-(AC/TG)22-3' and 5'-(GT/CA)17-3', were identified at approximately -5.7 kb and -3.4 kb upstream from the transcriptional initiation site of the mouse TPH gene, respectively. Minor allelic variants, 5'-(AC/TG)21-3' and 5'-(GT/CA)18-3', were observed in heterozygous pairs from 3 of 60 and 1 of 60 ICR mice, respectively. The identification of these microsatellites in the mouse TPH promoter raises the possibility that identical and/or other polymorphic sequences might exist in the upstream region of the human TPH gene.

In vitro cytotoxicity of novel platinum(II) coordination complexes containing diaminocyclohexane and diphenylphosphines

We have synthesized new platinum(H) analogs containing 1,2-diaminocyclohexane (dach) as a carrier ligand, 1,3-bis(diphenylphosphino) propane (DPPP) /1,2-bis(diphenylphosphino)ethane (DPPE) as a leaving group and nitrates to improve solubility. In the present study, the cytotoxicity of (Pt(trans-l-dach)(DPPP))cntdot2NO3 (KHPC-001) and (Pt(trans-l-dach)(DPPE)) cntdot 2NO3 (KHPC-002) was evaluated and compared on various P-388 cancer cell lines and porcine kidney cell line (LLC-PK1). The new platinum complexes demonstrated high efficacy on P-388 mouse leukemia cell line as well as cisplatin-resistant (P-388/CDDP) and adriamycin-resistant (P-388/ADR) P-388 cell lines. The intracellular platinum content was measured by a flame atomic absorption spectrophotometer (FAAS), and it was comparable to the results of IC50 of the three complexes on LLC-PK1I and P-388/S cells, while only DPPE compound was accumulated in high volume in P-388/ADR and P-388/CDDP cells. While the DNA-interstrand cross-links of KHPC-001, KHPC-002 and cisplatin were similar on P-388/S leukemia cells, these new platinum complexes were much less DNA cross-linking to a kidney derived cell line, LLC-PK1. These results indicate that KHPC-001 and KHPC-002 are a third-generation platinum complexes with potent antitumor activity and low nephrotoxicity.