Carcinoma, Hepatocellular ; pathology ; Cyclin-Dependent Kinase Inhibitor p21 ; biosynthesis ; genetics ; Humans ; Liver Neoplasms ; pathology ; Proto-Oncogene Proteins c-myc ; biosynthesis ; genetics ; Transfection ; Tumor Cells, Cultured ; Xeroderma Pigmentosum ; genetics

This study was focused on the circadian rhythms of DNA synthesis and the expression of c-myc gene in untreated and treated Eca-109 cells in human oesophageal cancer with isorhmnetin. The circadian rhythms of 3H-TdR incorporation and expression of c-myc gene in untreated and treated Eca-109 cells were measured by 3H-thymidine uptake assay and flow cytometry. The data collected were analyzed by ANOVA and Cosinor method. DNA synthesis and expression of c-myc gene in untreated group varied according to circadian time with statistical significance, the distribution curves of both DNA synthesis and the expression level of c-myc were fit for cosinor changes. The circadian rhythms of DNA synthesis and circadian parameters of c-myc expression in treated Eca-109 cells changed. The circadian parameters of DNA synthesis and expression level of c-myc varied after treatment by isorhmnetin. The effects of isorhmnetin on cell proliferation and c-myc expression reached the highest level from 20: 00 to 0: 00. The results provide a guidance for instituting the chemotherapy and chronotherapy of human tumors, when isorhmnetin is for use as anti-cancer agent.
Circadian Rhythm ; drug effects ; DNA ; biosynthesis ; Esophageal Neoplasms ; genetics ; metabolism ; pathology ; Flavonols ; pharmacology ; Humans ; Proto-Oncogene Proteins c-myc ; biosynthesis ; genetics ; Quercetin ; analogs & derivatives ; Tumor Cells, Cultured

Aldehydes ; pharmacology ; Animals ; Anthracenes ; pharmacology ; Cell Line ; Cell Proliferation ; drug effects ; Hepatocytes ; cytology ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; biosynthesis ; genetics ; Proto-Oncogene Proteins c-myc ; biosynthesis ; genetics ; Rats

The expression of a soluble protein on cell surface is often desirable for study of a functional protein, wide application of a protein or investigation of protein-protein interaction. The expression of a soluble protein on the surface of a cell is often achieved by genetically linking a protein to the extra-cellular fragment of a transmembrane partner. In this study, the myc epitope was linked with N terminal of transmembrane proteins either A2TM or deltaLNGFR amplified by overlapping PCR. The plasmids expressing fusion protein were transfected into 293FT cells and the expression of target proteins was evaluated by fluorescent microscope, flow cytometry and Western blotting. The results of flow cytometry revealed that both A2TM and deltaLNGFR were expressed on the cell surface, but A2TM could only be detected with high copy number. Western blotting showed that the expression level of deltaLNGFR was very high and protein was heavily glycosylated, by contrast the expression of A2TM was hardly detected. The results indicate that glycosylated deltaLNGFR is a good candidate partner for the expression of a soluble protein on the cell surface.
Apoptosis Regulatory Proteins ; biosynthesis ; genetics ; Cell Membrane ; metabolism ; Genes, MHC Class II ; genetics ; HLA-A2 Antigen ; biosynthesis ; genetics ; Humans ; Membrane Fusion Proteins ; genetics ; metabolism ; Membrane Proteins ; genetics ; metabolism ; Proto-Oncogene Proteins c-myc ; metabolism

The protooncogene c-myc is known to be associated with both cell proliferation and apoptosis. The possible cellular affects of castration on the ventral prostate gland of rat as well as the relationship to a castration induced c-myc expression were examined. Levels of c-myc mRNA in the ventral prostate gland peaked at 6 h (early induction) and 48 h (late induction) after castration, respectively. Castration-induced DNA fragmentation was not observed at an early induction of c-myc mRNA. DNA fragmentation appeared to be testosterone-dependent. On the other hand, cellular DNA synthesis measured by [3H]thymidine uptake in the ventral prostate gland was increased to maximum at 6 h after castration. These results suggest that an early induction of c-myc mRNA in ventral prostate gland after castration is closely associated with cell proliferation of the gland.
Animal ; Apoptosis ; Cell Division ; DNA Fragmentation ; Male ; *Orchiectomy ; Prostate/*cytology ; Proto-Oncogene Proteins c-myc/biosynthesis/*genetics ; RNA, Messenger ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To study the apoptosis of retina and the expression of c-myc protein in form-deprivation myopia. METHODS: Two-day-old chickens were sutured with right eyelid for 4, 8 and 12 weeks. After measurement of refracation, the eyeballs were observed by light microscope and taken photos. Retinal apoptotic cells were measured by TUNEL staining and flow cytometry. C-myc protein were examined by immunohistochemistry and flow cytometry. RESULTS: Lacquer crack lesions were found in sutured eyes at 12 weeks. Apoptotic cells were observed in retinal outer and inner nuclear layer of the sutured eyes at 12 weeks and obvious peak of apoptosis was observed in sutured eyes at 12 weeks. The expression of c-myc protein was significantly more than control eyes at 8 and 12 weeks. CONCLUSION The apoptosis of retinal was present in form-deprivation myopia with the degeneration of retina. C-myc protein plays an important role in retinal apoptosis of myopia.
Animals ; Animals, Newborn ; Apoptosis ; physiology ; Chickens ; Flow Cytometry ; Myopia ; metabolism ; pathology ; Proto-Oncogene Proteins c-myc ; biosynthesis ; genetics ; Random Allocation ; Retina ; metabolism ; pathology

In order to construct a eukaryotic expression vector of bovine c-myc gene, the coding sequence (CDS) of c-myc gene was amplified from bovine primordial genital ridges by RT-PCR. The CDS was subcloned into pMD19-T vector, and then inserted into vector pIRES2-AcGFP1-Nuc. After confirmed by restriction enzyme digestion and sequencing, the recombined plasmid was transfected into skin fibroblast cells. RT-PCR and Western Blotting were used to detect the expression of c-myc mRNA and protein, respectively. The results show that the complete CDS of c-myc gene was cloned from fetal bovine primordial genital ridges. The eukaryotic expression vector of bovine c-myc gene was constructed and efficiently expressed in the skin fibroblast cells. The present study will lay a good foundation for further study of c-myc gene function and bovine induced pluripotent stem cells from somatic cells by defined factors.
Animals ; Cattle ; Cloning, Molecular ; Fetus ; cytology ; Fibroblasts ; cytology ; Genetic Vectors ; genetics ; Proto-Oncogene Proteins c-myc ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Skin ; cytology ; Transfection

The aim of this study is to establish stable transfected cell lines which could produce SPAG4L protein labeled with Myc and His tags in vitro. The open reading frame (ORF) of human SPAG4L was amplified by PCR and the fragments were cloned into eukaryotic expression vector pcDNA3.1/myc-His(-)A. The recombined plasmids of pcDNA3.1/myc-His(-)A/SPAG4L were verified by sequencing and digestion with enzymes. Then, the recombined plasmids were introduced into HeLa cells and screened by G418. Western blotting was performed to detect the expression of SPAG4L and its tags in stable transfected cell lines. SPAG4L and its tags were expressed in the stable cell lines transfected with pcDNA3.1/myc-His(-)A/SPAG4L, but not in the control group. Further study showed that SPAG4L colocalized with the endoplasmic reticulum(ER) marker PDI by immunofluorescence. The stable transfected cell lines established in this study will provide a powerful tool for further studies such as co-immunoprecipitation and pull-down.
Carrier Proteins ; biosynthesis ; genetics ; Cloning, Molecular ; Female ; Genetic Vectors ; genetics ; HeLa Cells ; Histidine ; genetics ; Humans ; Male ; Proto-Oncogene Proteins c-myc ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; isolation & purification ; Transfection

OBJECTIVETo study telomerase activity and expression of oncogenes c-myc and p53 in tongue cancer, analyse the interaction among them, and assess their possible correlations with tongue cancer clinicopathological features.

METHODSTo detective the telomerase activity by TRAP and examine the positive expression of c-myc and p53 in tongue cancer by hybridization in situ.

RESULTSA high telomerase activity existed in lower differentiated tongue cancer (P < 0.05); the positive expression of c-myc increased significantly in lower grade tongue cancer (P < 0.05) and the positive expression of p53 decreased increasingly in tongue cancer accompanied with lymph node metastasis (P < 0.05).

CONCLUSIONTelomerase may play a key role in the tumorigenesis of tongue cancer. Meantime, c-myc and p53 exerts important effect on telomerase activation during the course of tongue cancer generation and development.

Adenocarcinoma ; enzymology ; genetics ; metabolism ; Adult ; Aged ; Carcinoma, Squamous Cell ; enzymology ; genetics ; metabolism ; Female ; Humans ; Lymphatic Metastasis ; Male ; Middle Aged ; Proto-Oncogene Proteins c-myc ; biosynthesis ; genetics ; Telomerase ; metabolism ; Tongue Neoplasms ; enzymology ; genetics ; metabolism ; Tumor Suppressor Protein p53 ; biosynthesis ; genetics

OBJECTIVETo study the anticancer activities of curcumin on human Burkitt's lymphoma and their molecular mechanism.

METHODSThe effect of curcumin on the growth of CA46 cells and apoptosis were studied through Trypan blue exclusion, MTT assay, cell cycle, DNA fragmentation analysis and detection of TdT-mediated dUTP nick end labeling (TUNEL). The effect of curcumin on the expression of c-myc, bcl-2, mutant-type p53 and Fas protein and mRNA was studied by flow cytometry (FCM) and reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS1. Curcumin inhibited proliferation of CA46 cells in a time- and dose-dependent manner, 2. CA46 cells treated with curcumin showed G(0)/G(1) or G(2)/M phase increase and S phase decrease, 3. CA46 cells apoptosis induced by curcumin was confirmed by DNA fragmentation and TUNEL and 4. The expression of c-myc, bcl-2, mutant-type p53 protein and mRNA was decreased sharply in CA46 cells treated with curcumin, while Fas protein and mRNA was increased.

CONCLUSIONCurcumin is able to inhibit the proliferation of CA46 cells and induce the cell apoptosis by down-regulating the expression of c-myc, bcl-2, mutant-type p53 and up-regulating the expression of Fas.

Antineoplastic Agents ; pharmacology ; Apoptosis ; Burkitt Lymphoma ; Cell Cycle ; drug effects ; Cell Division ; drug effects ; Curcumin ; pharmacology ; Gene Expression Regulation ; drug effects ; Humans ; Proto-Oncogene Proteins c-bcl-2 ; biosynthesis ; genetics ; Proto-Oncogene Proteins c-myc ; biosynthesis ; genetics ; Tumor Cells, Cultured ; Tumor Suppressor Protein p53 ; biosynthesis ; genetics ; fas Receptor ; biosynthesis ; genetics