Lamin B1 (LMNB1) is highly expressed in liver cancer tissues, and its influence and mechanism on the proliferation of hepatocellular carcinoma cells were explored by knocking down the expression of the protein. In liver cancer cells, siRNAs were used to knock down LMNB1. Knockdown effects were detected by Western blotting. Changes in telomerase activity were detected by telomeric repeat amplification protocol assay (TRAP) experiments. Telomere length changes were detected by quantitative real-time polymerase chain reaction (qPCR). CCK8, cloning formation, transwell and wound healing were performed to detect changes in its growth, invasion and migration capabilities. The lentiviral system was used to construct HepG2 cells that steadily knocked down LMNB1. Then the changes of telomere length and telomerase activity were detected, and the cell aging status was detected by SA-β-gal senescence staining. The effects of tumorigenesis were detected by nude mouse subcutaneous tumorigenesis experiments, subsequent histification staining of tumors, SA-β-gal senescence staining, fluorescence in situ hybridization (FISH) for telomere analysis and other experiments. Finally, the method of biogenesis analysis was used to find the expression of LMNB1 in clinical liver cancer tissues, and its relationship with clinical stages and patient survival. Knockdown of LMNB1 in HepG2 and Hep3B cells significantly reduced telomerase activity, cell proliferation, migration and invasion abilities. Experiments in cells and tumor formation in nude mice had demonstrated that stable knockdown of LMNB1 reduced telomerase activity, shortened telomere length, senesced cells, reduced cell tumorigenicity and KI-67 expression. Bioinformatics analysis showed that LMNB1 was highly expressed in liver cancer tissues and correlated with tumor stage and patient survival. In conclusion, LMNB1 is overexpressed in liver cancer cells, and it is expected to become an indicator for evaluating the clinical prognosis of liver cancer patients and a target for precise treatment.
Animals ; Mice ; Telomerase/metabolism* ; Carcinoma, Hepatocellular/genetics* ; Liver Neoplasms/genetics* ; Telomere Shortening ; In Situ Hybridization, Fluorescence ; Mice, Nude ; Telomere/pathology* ; Carcinogenesis

Humans ; Neuroendocrine Tumors/genetics* ; Prognosis ; X-linked Nuclear Protein/genetics* ; Pancreatic Neoplasms/pathology* ; Telomere/pathology*

This study was purposed to explore the relationship between the mRNA expression of telomere protection protein TIN2 and POT1 and the pathogenesis of myelodysplastic syndrome (MDS). The expression of TIN2 and POT1 genes at the mRNA levels were detected by real-time fluorescence quantitative PCR in 51 patients with MDS and 10 normal controls. The results showed that the mRNA expressions of TIN2 in RA/RARS/RCMD/MDS-U, RAEB-1 and RAEB-2 groups according to the World Health Organization criteria were significantly higher than that in the controls (P < 0.05); the mRNA expressions of POT1 in RA/RARS/RCMD/MDS-U, RAEB-1 and RAEB-2 groups were significantly lower than that in the controls (P < 0.05). The mRNA expressions of TIN2 in high-risk group, inter risk-2 group and inter risk-1 group according to the international prognostic scoring system criteria were significantly higher than that in controls (P < 0.05). There was no significant difference between low risk group and the control group. The mRNA expressions of POT1 in high risk group, inter-risk-2 group and inter-risk-1 group were significantly lower than the controls (P < 0.05). There was no significant difference between low risk group and the control group. The mRNA expression of TIN2 in normal chromosome group was significantly lower than that in abnormal chromosome group (P < 0.05). There was no significant difference between normal chromosome group and the control group. The mRNA expression of POT1 in normal chromosome group was significantly higher than that in abnormal chromosome group (P < 0.05). There was no significant difference between normal chromosome group and the control group. It is concluded that the abnormal mRNA expression of TIN2 and POT1 may be involved in the regulation of telomere dynamics of MDS patients, the regulatory mechanism may be related to the telomere length and the pathogenesis of MDS.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Bone Marrow ; metabolism ; pathology ; Case-Control Studies ; Cell Adhesion Molecules ; genetics ; metabolism ; Female ; Humans ; Male ; Middle Aged ; Myelodysplastic Syndromes ; genetics ; metabolism ; pathology ; RNA, Messenger ; genetics ; Telomere ; metabolism ; Telomere-Binding Proteins ; genetics ; metabolism ; Young Adult

Telomere Length Changes in Colorectal Cancers and Polyps Telomere shortening and telomerase activation occur frequently in cases of colorectal carcinoma. In this study, we correlated the clinicopathological parameters with the telomere length in colorectal carcinomas, colonic polyps, and normal colonic tissues. We also investigated whether the telomere length changes reflect the biologic behavior of tumors and different modes of tumor development. Telomere length was determined by terminal restriction fragment Southern blot analysis in 20 invasive colorectal carcinomas and normal mucosa from the same patients. We also examined 20 colonic polyps and associated normal mucosa. Telomere shortening was detected in 16/20 (80%), and telomere elongation in 2/20 (10%) cases of colorectal carcinoma, and no changes in 2 subjects. In the colonic polyp patients, shortening was detected in 4/20 (20%), elongation in 6/20 (30%), and no change in 10/20 (50%). The frequency of telomere shortening was significantly different between colorectal carcinoma and polyp groups. Decreased telomere length was noted in 92.9% (13/14) of Dukes' C and 50% (3/6) of Dukes' B. The difference between these two sub-groups was statistically significant. This study suggests that the telomere length in colorectal carcinomas is decreased upon the development of malignancy. A significant difference in telomere length between polyps and invasive colorectal carcinomas may reflect a different biologic behavior of colorectal carcinomas.
Adult ; Aged ; Blotting, Southern ; Carcinoma/*pathology ; Colonic Polyps/*pathology ; Colorectal Neoplasms/*pathology ; Female ; Humans ; Lymphatic Metastasis ; Male ; Middle Aged ; Telomere/genetics/*pathology

OBJECTIVETo investigate the changes of the human telomerase reverse transcriptase gene (hTERT) alterative splicing pattern in gastric carcinogenesis.

METHODSThree alternative splicing sites (alpha, beta, gamma) were selected to design primers. The expression of eight hTERT alternative splicing variants (ASVs) in normal gastric mucosa, precancerous lesions and gastric cancer was detected by semi-nested reverse transcription-polymerase chain reaction (RT-PCR). The expression of beta site-remaining ASV (beta (+) hTERT mRNA) in precancerous lesions and gastric cancer tissues was detected by SYBR green real-time RT-PCR.

RESULTSThe positive rate of alpha(+) beta(+)gamma(+) hTERT mRNA was significantly higher in gastric cancer than in precancerous lesions and normal mucosa (94.7% vs. 40.0% and 0, P<0.05). The positive rates of other ASVs were not different among the three groups. The positive rates of beta deletion ASV were 72.2% in normal mucosa, 95.0% in precancerous lesions and 100.0% in gastric cancer. The mRNA level of beta(+) hTERT was 5.49 folds higher in gastric cancer than in precancerous lesions.

CONCLUSIONThe hTERT alternative splicing pattern changes during gastric carcinogenesis. The beta(+) hTERT mRNA is expressed increasingly during gastric carcinogenesis and may provide useful information for diagnosis of gastric cancer or precancerous lesions.

Alternative Splicing ; genetics ; Cell Transformation, Neoplastic ; genetics ; pathology ; Cells, Cultured ; Gene Expression Regulation, Neoplastic ; physiology ; Humans ; Precancerous Conditions ; RNA, Messenger ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Stomach Neoplasms ; genetics ; metabolism ; pathology ; Telomerase ; classification ; genetics ; metabolism ; Telomere ; genetics

Hepatocellular carcinoma (HCC) is one of the most common malignant diseases in the world. The hepatitis B virus (HBV) replicates non-cytopathically in hepatocytes, and most of the liver injury associated with this infection reflects the immune response. Epidemiological studies have clearly demonstrated that a chronic HBV infection is a major etiological factor in the development of HCC. The pathogenesis of HBV-associated HCC has been studied extensively, and the molecular changes during the malignant transformation have been identified. The main carcinogenic mechanism of HBV-associated HCC is related to the long term-inflammatory changes caused by a chronic hepatitis B infection, which might involve the integration of the HBV. Integration of the HBV DNA into the host genome occurs at the early steps of clonal tumorous expansion. The hepatitis B x protein (HBx) is a multifunctional regulatory protein that communicates directly or indirectly with a variety of host targets, and mediates many opposing cellular functions, including its function in cell cycle regulation, transcriptional regulation, signaling, encoding of the cytoskeleton and cell adhesion molecules, as well as oncogenes and tumor suppressor genes. Continued study of the mechanisms of hepatocarcinogenesis will refine our current understanding of the molecular and cellular basis for neoplastic transformations in the liver. This review summarizes the current knowledge of the mechanisms involved in HBV-associated hepatocarcinogenesis.
Apoptosis/genetics ; Carcinoma, Hepatocellular/pathology/*virology ; Cell Cycle ; DNA Mismatch Repair ; Hepatitis B virus/genetics/*pathogenicity ; Hepatitis B, Chronic/*complications ; Humans ; Liver Neoplasms/pathology/*virology ; Neovascularization, Pathologic/genetics/virology ; Telomere/genetics ; Trans-Activators/*metabolism ; Transcription, Genetic

OBJECTIVEBy testing the changes of telomere binding protein in malignant transformation BEAS-2B cells induced by coal tar pitch smoke extracts, to study the role of protection of telomeres 1 (POT1), telomeric repeat binding factor 1 (TRF1) and TRF2 in tumorgenesis that contact with coal tar pitch.

METHODSThe BEAS-2B cells were induced by coal tar pitch smoke extracts to form malignant transformation cell model in vitro. The gene expression levels of mRNA were assessed by real-time quantitative RT-PCR, the protein expression variations were determined by cell culture overslip of immunohistochemical methods.

RESULTSIn malignant transformation cells, the mRNA expression level (POT1: 0.63 ± 0.04, TRF1: 0.36 ± 0.01) and the protein expression level (POT1: 0.36 ± 0.05, TRF1: 0.09 ± 0.03) of POT1 and TRF1 was statistically significant decreased compared to that of BEAS-2B group (mRNA: POT1: 1.00 ± 0.04, TRF1: 1.01 ± 0.16; protein: POT1: 0.55 ± 0.07, TRF1: 0.27 ± 0.07) and DMSO group (mRNA: POT1: 0.89 ± 0.12, TRF1: 0.90 ± 0.08; protein: POT1: 0.55 ± 0.10, TRF1: 0.26 ± 0.04) (P < 0.05); mRNA expression level (1.45 ± 0.07) and the protein expression level (0.88 ± 0.06) of TRF2 was increased compared to that of BEAS-2B group (mRNA: 1.00 ± 0.07, protein: 0.48 ± 0.06) and DMSO group (mRNA: 1.00 ± 0.06, protein: 0.50 ± 0.06) (P < 0.05).

CONCLUSIONThe change of gene and protein expression level in POT1, TRF1, and TRF2 involved in the process that evolved into malignant transformation in bronchial epithelial cells BEAS-2B induced by coal tar pitch smoke extracts.

Cell Line ; Cell Transformation, Neoplastic ; metabolism ; Coal Tar ; toxicity ; Epithelial Cells ; cytology ; metabolism ; pathology ; Humans ; Repetitive Sequences, Nucleic Acid ; Telomere-Binding Proteins ; genetics ; metabolism

This study was aimed to detect the telomere length and the telomerase expression activity in patients with chronic lymphocytic leukemia (CLL), and investigate their relation to prognosis of CLL. The telomere length and the telomerase expression activity of peripheral blood and / or bone marrow mononuclear cells were examined by Tel-FISH, a semi-quantitative method and by TRAP-ELISA respectively; the expressions of ZAP70 and CD38 were detected by flow cytometry. The results showed that comparing the telomere length in different stages, there was a tendency that the telomere became prolonged when the stage raised up. There was statistical significant difference between Rai stages III-IV and stage 0, Rai stages III-IV and stages I-II, Binet stage C and stage A, Binet stage C and stage B; while no statistical significant difference existed between Rai stage 0 and stages I-II, Binet stage A and stage B. The telomere length in ZAP70 negative group was found similar as in ZAP70 positive group. The telomere length in CD38 positive group was shorter than that in CD38 negative group, but there was no statistical difference between them. Comparing the telomerase expression activity between different stages, there was a tendency that it increased when the stages went up; comparing the telomerase expression activity at different Rai stages, it increased at the higher stages. One case of CLL demonstrated that telomerase expression did not show at remission stage, but was found at relapse stage, which suggested that telomerase expression may relate to prognosis of disease. It is concluded that the telomerase length is in relation to Rai and Binet stage, which was shorter at higher stage than that at lower stage and intermediate stage. It seemed that the telomerase expression activity increased at higher stages. The expression of telomerase in mononuclear cells is stable and not influenced by treatment.
Adult ; Aged ; Aged, 80 and over ; Female ; Humans ; Leukemia, Lymphocytic, Chronic, B-Cell ; metabolism ; pathology ; Male ; Middle Aged ; Telomerase ; metabolism ; Telomere ; genetics

OBJECTIVETo screen the exon12 mutation of pot1 gene in cultured human carcinoma cell strains (lines).

METHODSThe chromosomal DNA was extracted from 27 cultured carcinoma cell strains (lines). The exon 12 of pot1 gene was amplified by PCR, and the product was purified and screened. The screening results were compared with the data of GenBank and NCBI and the exon 12 mutations in cultured human carcinoma cell strains (lines) analyzed.

RESULTSThe exon12 sequence of pot1 could be specifically amplified using the designed primers. Direct sequence analysis of the PCR products after purification showed that 4 of the 5 carcinoma cell lines of the female genital system such as Hela and HO8910-PM cells shared the same transition (G17722-->C) in exon12 of human pot1 gene resulting in a conversion of G1385-->C in the cDNA and amino acid change of Leu454-->Phe in the translated polypeptide. The rest of the 23 cell strains (lines) from different origins showed no such mutation.

CONCLUSIONThe exon12 (17,722 bp) is a mutant region specific for female genital system tumor.

Amino Acid Sequence ; Base Sequence ; Cell Line, Tumor ; DNA Mutational Analysis ; Exons ; genetics ; Female ; HeLa Cells ; Humans ; K562 Cells ; Molecular Sequence Data ; Neoplasms ; genetics ; pathology ; Point Mutation ; Telomere-Binding Proteins ; genetics

OBJECTIVETo detect mutations of human telomeric repeat binding factor 1 (TERF1) gene in 11 malignant hematopoietic cell lines, which have positive telomerase activity, and evaluate the significance of the mutations.

METHODSGenome structure of TERF1 was predicted by using biology information program, and verified by PCR and sequencing. Telomerase activity was detected by telomeric repeat amplification (TRAP)-ELISA. PCR and sequencing were used to detect mutation of each exon of TERF1 in 11 cell lines, including myelogenous leukemia cell lines K562, HL-60, U-937, NB4, THP-1, HEL and Dami; lymphoblastic leukemia cell lines 6T-CEM, Jurkat and Raji and MDS-RAEB cell line MUTZ-1. Five DNA samples from healthy volunteers were detected as normal controls.

RESULTSTERF1 gene has 10 exons and spans 38.6 kb. All the 11 cell lines showed positive telomerase activity. No mutation was found in all exons of TERF1 in the 11 cell lines. However, 4 variants were found in intron1, 2 and 8 near exon1, exon2 and exon9, respectively. The variants in MUTZ-1 was different from those in leukemia cell lines; but no difference was found between the variants in myelogenous and lymphoblastic leukemia cell lines.

CONCLUSIONTERF1 mutation is probably not among the main factors of the gene dysfunction in malignant hematopoietic diseases.

Base Sequence ; Cell Line, Tumor ; DNA Mutational Analysis ; Enzyme-Linked Immunosorbent Assay ; Exons ; genetics ; HL-60 Cells ; Hematologic Neoplasms ; genetics ; metabolism ; pathology ; Humans ; Jurkat Cells ; K562 Cells ; Mutation ; Polymerase Chain Reaction ; Telomerase ; metabolism ; Telomere-Binding Proteins ; genetics ; metabolism ; U937 Cells