Wyniki wyszukiwania

1

The role of alternative splicing in the regulation of telomerase reverse transcriptase [TERT] gene expression in rice [Oryza sativa L.]

100%

Heller-Uszynska K., Kilian A.

Polish Journal of Natural Sciences. Supplement

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2003

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tom 01

2

Can CYP1A1 siRNA be an effective treatment for lung cancer?

84%

Mohammed K., Shervington A.

Cellular and Molecular Biology Letters

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2008

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tom 13

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nr 2

240-249

Abstract: Previously, we identified a novel correlation between the upregulated expression of telomerase (hTERT) and cytochrome P450 1A1 (CYP1A1) in A549 human lung cancer cell line. The expression correlation was confirmed by silencing CYP1A1 expression using siRNA technology and observing a silencing of hTERT transcription. Furthermore, silencing CYP1A1 and subsequently downregulating hTERT resulted in the reduction of cancer cell viability by more than 40%, which appeared as early as 24 hours after the treatment. The concomitant downregulation of CYP1A1 and hTERT resulted in rapid cell death. This finding can be further exploited to develop new molecular targets for the treatment of lung cancer.

3

Differences in the expression of telomerase and prostate-specific membrane antigen in non-advanced prostatic cancer

84%

Gasinska A., Luczynska E., Wilk W., Cichocka A.

Folia Histochemica et Cytobiologica

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2013

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tom 51

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nr 1

4

Effect of antioestrogens on proliferation, differentiation and telomerase activity of pig granulosa cells in vitro

84%

Chronowska E., Tomanek M., Kott T.

Journal of Animal and Feed Sciences

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2010

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tom 19

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nr 4

5

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Telomeropathies: rare disease syndromes

84%

Panczyszyn A., Boniewska-Bernacka E.

Medical Science Pulse

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2018

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tom 12

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nr 2

Telomeres are located at the end of the chromosomes. They protect chromosomes from fusion and degradation. Every cell division causes a shortening of the telomeres. A special enzymatic complex called telomerase is responsible for maintaining telomere length in intensively dividing cells, such as epithelial cells and bone marrow cells. The enzymatic complex includes the TERT subunit, which has reverse transcriptase activity, and the TERC subunit, which acts as a template. Other important components of telomerase are the proteins that are responsible for structural stability. Telomerase remains active only in the dividing cells of the body. The rate of telomere shortening depends on many factors including age, sex, and comorbidities. Faster shortening of telomeres is caused by gene defects, which have an impact on telomerase action. Collectively, these are called telomeropathies. Common causes of telomeropathies are mutations in the TERT and TERC telomerase genes. Types of telemeropathies include dyskeratosis congenita, idiopathic pulmonary fibrosis, and aplastic anaemia, among others. Clinical manifestations and prognoses depend on the type and quantity of mutated genes. Diagnosis of telomeropathies is often problematic because they present with the same symptoms as other diseases. So far, no effective therapeutic methods have been developed for telomeropathies. A therapeutic method for patients with bone marrow failure may be the transplantation of hematopoietic stem cells. For patients with idiopathic pulmonary fibrosis, treatments include immunosuppressive therapy, lung transplantation, or palliative care. In the future, gene therapy may be an effective treatment strategy for telomeropathies. Lifestyle changes may also have a positive impact on the person. Physical activity combined with a healthy diet rich in antioxidants and unsaturated fatty acids can decrease the oxidative stress levels in cells and lead to a slower shortening of the telomeres.

6

Fragments of LINE-1 retrotransposons flanked by inverted telomeric repeats are present in the bovine genome. Homology with human LINE-1 elements

84%

Plucienniczak G., Plucienniczak A.

Acta Biochimica Polonica

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1999

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tom 46

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nr 4

In the bovine genome we found two intrachromosomal DNA fragments flanked by inverted telomeric repeats (GenBank Accession Nos. AF136741 and AF136742). The internal parts of the fragments are homologous exclusively to the human sequences and to the consensus sequence of the L1MC4 subfamily of LINE-1 retrotransposons which are widespread among mammalian genomes. We found that distribution of homologous human sequences within our fragments is not random, reflecting a complicated pattern of insertion mechanisms of and maintenance of retrotransposons in mammalian genomes. One of the possible explanations of the origin of LINE-1 truncated elements flanked by inverted telomeric repeats in the bovine genome is that extrachromosomal DNA fragments may be modified by telomerase and subsequently, transferred into chromosomal DNA.

7

The activity of human telomerase in the cells of acute leukaemias

84%

Kocki J., Kolano J., Cioch M., Dmoszynska A., Wojcierowski J.

Folia Morphologica

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2004

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tom 63

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nr 1

Telomeres are the end fragments of chromosomes formed by a number of non-coding double-stranded TTAGGG repeats in vertebrates. During cell division the number of repeats decreases, leading to cell senescence or apoptosis. In immortal cells, including cancer cells, the telomere length is stable and maintained by, among other factors, telomerase. The aim of the study is to compare telomerase activity in normal lymphocytes and in leukaemic cells. Samples of acute leukaemia cells, HL 60 cell line and the lymphocytes of healthy volunteers were examined. Telomerase analysis was performed using TeloTAGGG Telomerase PCR ELISAplus (Roche). The relative telomerase activities (RTA) in leukaemic and normal cells were analysed. A high level of RTA was observed in leukaemic cells.

8

The human telomerase catalytic subunit and viral telomerase RNA reconstitute a functional telomerase complex in a cell-free system, but not in human cells

67%

Trapp-Fragnet L., Marie-Egyptienne D. T., Fakhoury J., Rasschaert D., Autexier C.

Cellular and Molecular Biology Letters

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2012

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tom 17

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nr 4

The minimal vertebrate telomerase enzyme is composed of a protein component (telomerase reverse transcriptase, TERT) and an RNA component (telomerase RNA, TR). Expression of these two subunits is sufficient to reconstitute telomerase activity in vitro, while the formation of a holoenzyme comprising telomerase-associated proteins is necessary for proper telomere length maintenance. Previous reports demonstrated the high processivity of the human telomerase complex and the interspecies compatibility of human TERT (hTERT). In this study, we tested the function of the only known viral telomerase RNA subunit (vTR) in association with human telomerase, both in a cell-free system and in human cells. When vTR is assembled with hTERT in a cell-free environment, it is able to interact with hTERT and to reconstitute telomerase activity. However, in human cells, vTR does not reconstitute telomerase activity and could not be detected in the human telomerase complex, suggesting that vTR is not able to interact properly with the proteins constituting the human telomerase holoenzyme.

9

Telomere shortening and ageing of the immune system

67%

Kaszubowska L.

Journal of Physiology and Pharmacology. Supplement

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2008

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tom 59

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nr 9

169-186

10

Sensitivity of natural killer cells to activation in the process of ageing is related to the oxidative and inflammatory status of the elderly

67%

Kaszubowska L., Kaczor J. J., Hak L., Dettlaff-Pokora A., Szarynska M., Kmiec Z.

Journal of Physiology and Pharmacology

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2011

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tom 62

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nr 1

The role of the innate immunity during human ageing is not well understood. The aim of the study was to estimate reactivity of NK (natural killer) cells in the very old (mean age 91 years) and old subjects (mean age78 years) compared to young individuals (mean age 26 years) in respect to the indices of the oxidative stress (telomere length of NK cells, serum content of –SH groups), serum total antioxidant status and serum concentrations of interleukin 6 and tumor necrosis factor- (TNF-). The activation state of NK cells, reflected by telomerase activity and intracellular interferon (IFN) content, was also measured. We found that length of telomeres in NK cells and serum concentration of -SH groups decreased both in the old and the oldest subjects as compared to young individuals. The oldest seniors, on the contrary to the old ones, revealed similar level of serum antioxidant status as the young subjects. The serum level of IL-6, not detectable in the young subjects, did not differ in the oldest and old seniors. TNF- serum concentrations progressively increased with age. After stimulation, NK cells of both old groups showed higher intracellular levels of IFN than young subjects. IL-2-activated NK cells of the oldest seniors showed the highest increase of telomerase activity as compared to the other age groups. Serum level of IL-6 correlated positively with activation markers of NK cells. Moreover, in seniors but not in young subjects, the number of active, IFN-expressing NK cells, correlated positively with the serum content of the –SH groups. These findings indicate that sensitivity of NK cells to activation is maintained during ageing and this phenomenon may be related to the oxidative and inflammatory status of the elderly.

11

Immunohistochemical localisation of telomerase in mammary adenocarcinoma in bitches

67%

Nowak M., Madej J. A., Dziegiel P., Dzimira S.

Bulletin of the Veterinary Institute in Puławy

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2008

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tom 52

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nr 1

The studies were aimed at immunohistochemical determination of telomerase expression in cells of primary adenocarcinomas in mammary glands of bitches. Moreover, it was aimed at comparing the obtained results with an extent of Ki-67 antigen expression, which reflects the proliferation rate of tumour cells. Material for the studies was sampled during surgery in 35 bitches of various breed, ranging in age from 5 to 14 years, which developed mammary tumour. Using histopathology, the tumours were verified as representing adenocarcinomas. This was followed by immunohistochemical reactions for the detection of telomerase and Ki-67 expression. The obtained preparations were photographed and the images were subjected to computer-assisted analysis using the MultiScaneBase V 14.02 software. The obtained mean positive correlation (r = 0.26) between the expression of Ki-67 proliferative antigen and that of telomerase in mammary adenocarcinoma of bitches points at the involvement of the enzyme in neoplastic processes in animals, in an analogy to breast cancers in women.

Ograniczanie wyników

The role of alternative splicing in the regulation of telomerase reverse transcriptase [TERT] gene expression in rice [Oryza sativa L.]

Can CYP1A1 siRNA be an effective treatment for lung cancer?

Differences in the expression of telomerase and prostate-specific membrane antigen in non-advanced prostatic cancer

Effect of antioestrogens on proliferation, differentiation and telomerase activity of pig granulosa cells in vitro

Telomeropathies: rare disease syndromes

Fragments of LINE-1 retrotransposons flanked by inverted telomeric repeats are present in the bovine genome. Homology with human LINE-1 elements

The activity of human telomerase in the cells of acute leukaemias

The human telomerase catalytic subunit and viral telomerase RNA reconstitute a functional telomerase complex in a cell-free system, but not in human cells

Telomere shortening and ageing of the immune system

Sensitivity of natural killer cells to activation in the process of ageing is related to the oxidative and inflammatory status of the elderly

Immunohistochemical localisation of telomerase in mammary adenocarcinoma in bitches