Telomere length as a prognostic marker in breast and lung cancer

Komórki nowotworowe charakteryzuje podwyższona aktywność telomerazy. Enzym ten jest odpowiedzialny zaodbudowę telomerów. Telomery, jako wyspecjalizowane nukleoproteiny występujące na końcach chromosomów,pełnią istotną rolę w utrzymaniu stabilności i integralności genomu. Najważniejszym skutkiem ich ciągłej odbudowyw komórkach nowotworowych przy udziale telomerazy jest nadawanie im nieśmiertelności. Badania prowadzonew ostatnich latach nad aktywnością telomerazy oraz długością telomerów wskazują, że ich regulacja odbywa sięprzy udziale czynników uwalnianych podczas procesu karcenogenezy, tj. hormonów i cytokin. Czynniki te z koleimodulują telomerazę i telomery także w pozostałych, prawidłowych komórkach. Powoduje to, że zmiany zachodzącew organizmie człowieka nawet w skali lokalnej (inicjacja nowotworu na poziomie pojedynczej komórki) mogą miećswoje odzwierciedlenie na szczeblu molekularnym w całym organizmie (w tym w leukocytach) i odwrotnie.Najnowsze badania wskazują na pewne różnice w długości telomerów mierzonych w leukocytach pomiędzy chorymina nowotwory typu adenocarcinoma a osobami z grupy kontrolnej. Biorąc pod uwagę rezultaty dotychczasowychbadań, słusznym wydaje się więc przyjęcie tezy, że długość telomerów (lub aktywność telomerazy) w leukocytachmoże być postrzegana jako marker procesu nowotworzenia zachodzącego na bardzo wczesnym etapie karcenogenezy.Wydaje się więc, że ocena długości telomerów w leukocytach, jako badanie o niskiej inwazyjności, mogłaby stać sięmetodą wczesnego wykrywania zmian nowotworowych zachodzących w organizmie człowieka.W pracy podjęliśmy się przedyskutowania problemu możliwości wykorzystania analizy długości telomerów jakoparametru prognostycznego na wczesnym etapie rozwoju nowotworów na przykładzie raka piersi i raka płuca.Prezentujemy też kilka powszechnie do tego celu wykorzystywanych metod z analizą ich mocnych i słabych stron.Cancer cells are characterized by an increased telomerase activity. The enzyme is responsible for reconstruction oftelomeres. Telomeres, as specialized nucleoproteins that are located at the end of chromosomes, provide genomestability and integrity. The most important consequence of their restore in cancer cells is their immortality. The studiescarried out within last few years on telomerase and telomere length indicate that their regulation is controlledby factors released during carcinogenesis i.e. hormones and cytokines. Consequently, those factors also modulatetelomerase also in normal cells.This causes changes in the human organism even at the local area (cancer initiation at a single cell level) which maybe reflected by alterations in whole organism (including leukocytes). The latest studies point to some differences inthe measured telomere length in leukocytes between adenocarcinoma patients and control subjects. Consideringthe results of previous studies it seems justified to adopt the thesis that telomere length (or telomerase activity) inleukocytes can be evaluated as a marker of tumor occurring at a very early stage of carcinogenesis. Thus, it seemsthat telomere length measurement in leukocytes, as a low-invasive method, might be a good method for predictiveassessment of carcinogenesis. In this work we focused on potential application of telomere length analysis as a prognostic parameter at the early stage of cancer development in breast and lung cancer. We also report on numerous methods of telomere length analysis showing their strengths and weaknesses

Badania polimorfizmów genów CYP1A1, CYP1B1 i CYP3A4 u chorych z rakiem piersi

Abstract Background: The role of CYP1A1, CYP1B1 and CYP3A4 polymorphism in pathogenesis of breast cancer has not been fully elucidated. From three CYP1A1 polymorphisms *2A (3801T>C), *2C (2455A>G), and *2B variant, which harbors both polymorphisms, the *2A variant is potentially carcinogenic in African Americans and the Taiwanese, but not in Caucasians, and the CYP1B1*2 (355G>T) and CYP1B1*3 (4326C>G) variants might increase breast cancer risk. Although no association of any CYP3A4 polymorphisms and breast cancer has been documented, the CYP3A4*1B (392A>G) variant, correlates with earlier menarche and endometrial cancer secondary to tamoxifen therapy. Objective: The present study was designed to investigate the frequency of CYP1A1, CYP1B1 and CYP3A4 polymorphisms in a sample of breast cancer patients from the Polish population and to correlate the results with the clinical and laboratory findings. Material and methods: The frequencies of CYP1A1*2A; CYP1A1*2C; CYP1B1*3; CYP3A4*1B CYP3A4*2 polymorphisms were determined in 71 patients aged 36-87, with primary breast cancer and 100 healthy individuals. Genomic DNA was extracted from the tumor, and individual gene fragments were PCR-amplified. The polymorphisms were determined by RFLP and were correlated with the patients’ TNM stage, grade, estrogen and progesterone receptor status as well as the level of c-erbB-2 protein. Results: CYP1A1 polymorphisms were more frequent in younger patients and in the patients with high level of c erbB 2 protein. No correlation between these polymorphisms and the cancer stage or grade, as well as the receptor status was demonstrated. Conclusions: CYP1A1 polymorphisms probably predispose to an earlier onset of breast cancer and might be associated with higher c-erbB-2 protein level, but further studies on a much larger group are required to substantiate our findings.Streszczenie Wstęp: Rola polimorfizmów genów CYP1A1, CYP1B1 oraz CYP3A4 w patogenezie raka piersi nie została w pełni wyjaśniona. Spośród trzech polimorfizmów CYP1A1*2A (3801T>C), *2C (2455A>G), oraz *2B, który zawiera oba warianty, tylko wariant *2A jest potencjalnie rakotwórczy u afro-amerykanów i mieszkańców Tajwanu, ale nie u rasy kaukaskiej, natomiast polimorfizmy CYP1B1*2 (355G>T) i CYP1B1*3 (4326C>G) mogą zwiększać ryzyko rozwoju raka piersi. Chociaż nie stwierdzono związku żadnego z polimorfizmów CYP3A z rakiem piersi, dowiedziono, że wariant CYP3A4*1B (392A>G) współistnieje z wcześniejszym występowaniem miesiączki oraz rakiem endometrium w następstwie leczenia tamoksyfenem. Cel: Celem badań było oznaczenie częstości występowania polimorfizmów CYP1A1, CYP1B1 i CYP3A4 w grupie chorych z rakiem piersi z populacji polskiej oraz poszukiwanie korelacji z wynikami badań klinicznych i laboratoryjnych. Materiał i metody: Częstości polimorfizmów CYP1A1*2A; CYP1A1*2C; CYP1B1*3; CYP3A4*1B i CYP3A4*2 oznaczono u 71 chorych (w wieku 36-87 lat) oraz 100 zdrowych kobiet. Genomowy DNA wyekstrahowano z tkanki guza i fragmenty poszczególnych genów amplifikowano za pomocą PCR. Polimorfizmy wykrywano techniką RFLP i korelowano ich występowanie ze stopniem zaawansowania klinicznego i histologicznego nowotworu, obecnością receptorów estrogenów i progesteronu jak również poziomem białka c-erbB-2. Wyniki: Polimorfizmy CYP1A1 częściej występowały u młodszych chorych oraz u chorych z wysokim poziomem białka c-erbB-2. Nie wykazano korelacji pomiędzy obecnością polimorfizmów a stopniem zaawansowania nowotworu czy obecnością receptorów. Wnioski: Polimorfizmy CYP1A1 przypuszczalnie predysponują do wcześniejszego występowania raka piersi i mogą wiązać się z podwyższeniem poziomu białka c-erbB-2, lecz potwierdzenie tych spostrzeżeń wymaga dalszych badań w większych grupach pacjentów

Binding Study of the Fluorescent Carbazole Derivative with Human Telomeric G-Quadruplexes

The carbazole ligand 3 was synthesized, characterized and its binding interactions with human telomeric (22HT) G-quadruplex DNA in Na+ and K+-containing buffer were investigated by ultraviolet-visible (UV-Vis) spectrophotometry, fluorescence, circular dichroism (CD) spectroscopy, and DNA melting. The results showed that the studied carbazole ligand interacted and stabilized the intramolecular G-quadruplexes formed by the telomeric sequence in the presence of sodium and potassium ions. In the UV-Vis titration experiments a two-step complex formation between ligand and G-quadruplex was observed. Very low fluorescence intensity of the carbazole derivative in Tris HCl buffer in the presence of the NaCl or KCl increased significantly after addition of the 22HT G4 DNA. Binding stoichiometry of the ligand/G-quadruplex was investigated with absorbance-based Job plots. Carbazole ligand binds 22HT with about 2:1 stoichiometry in the presence of sodium and potassium ions. The binding mode appeared to be end-stacking with comparable binding constants of ~105 M−1 as determined from UV-Vis and fluorescence titrations data. The carbazole ligand is able to induce formation of G4 structure of 22HT in the absence of salt, which was proved by CD spectroscopy and melting studies. The derivative of carbazole 3 shows significantly higher cytotoxicity against breast cancer cells then for non-tumorigenic breast epithelial cells. The cytotoxic activity of ligand seems to be not associated with telomerase inhibition

Human Vault RNAs: Exploring Their Potential Role in Cellular Metabolism

Non-coding RNAs have been described as crucial regulators of gene expression and guards of cellular homeostasis. Some recent papers focused on vault RNAs, one of the classes of non-coding RNA, and their role in cell proliferation, tumorigenesis, apoptosis, cancer response to therapy, and autophagy, which makes them potential therapy targets in oncology. In the human genome, four vault RNA paralogues can be distinguished. They are associated with vault complexes, considered the largest ribonucleoprotein complexes. The protein part of these complexes consists of a major vault protein (MVP) and two minor vault proteins (vPARP and TEP1). The name of the complex, as well as vault RNA, comes from the hollow barrel-shaped structure that resembles a vault. Their sequence and structure are highly evolutionarily conserved and show many similarities in comparison with different species, but vault RNAs have various roles. Vaults were discovered in 1986, and their functions remained unclear for many years. Although not much is known about their contribution to cell metabolism, it has become clear that vault RNAs are involved in various processes and pathways associated with cancer progression and modulating cell functioning in normal and pathological stages. In this review, we discuss known functions of human vault RNAs in the context of cellular metabolism, emphasizing processes related to cancer and cancer therapy efficacy

The effect of indole-3-carbinol on the expression of CYP1A1, CYP1B1 and AhR genes and proliferation of MCF-7 cells

The influence of an antiestrogen, indole-3-carbinol (I3C) on the expression of CYP1A1, CYP1B1 and AhR genes was investigated in an attempt to establish whether I3C could increase the expression of genes involved in estrone metabolism. Another purpose was to examine the proliferation of an estrogen-dependent breast cancer cell (MCF-7 line) under the influence of I3C and both I3C and DDT. In MCF-7 cells incubated with I3C or I3C and DDT combined, quantitative RT-PCR analysis revealed a significant increase in the level of CYP1A1, AhR, and CYP1B1 transcripts. The proliferation rate of MCF-7 cells was increased by treatment with DDT or estradiol (E2), whereas I3C did not affect the proliferation of MCF-7 cells but greatly reduced the stimulatory effect of DDT, and abolished the effect of E2. The level of p21 transcript, encoding p21 protein involved in the cell cycle, was increased several-fold by I3C comparing to its level in cells incubated with estradiol or DDT. The results suggest that the proliferation of MCF-7 cells is accompanied not only by expression of genes encoding cytochromes involved in estrogen metabolism, but also by changes in the expression of other genes including that encoding p21 protein involved in the cell cycle

Early Smartphone App-Based Remote Diagnosis of Silent Atrial Fibrillation and Ventricular Fibrillation in a Patient with Cardiac Resynchronization Therapy Defibrillator

Due to distressing statistics concerning cardiovascular diseases, remote monitoring of cardiac implantable electronic devices (CIED) has received a priority recommendation in daily patient care. However, most bedside systems available so far are not optimal due to limited patient adherence. We report that smartphone app technology communicating with CIED improved the patient’s engagement and adherence, as well as the accuracy of atrial and ventricular arrhythmias diagnosis, thus offering more efficient treatment and, consequently, better patient clinical outcomes. Our findings are in concordance with previously published results for implantable loop recorders and pacemakers, and provide new insight for heart failure patients with an implanted cardiac resynchronization therapy defibrillator

The Role of Telomerase in Breast Cancer’s Response to Therapy

Currently, breast cancer appears to be the most widespread cancer in the world and the most common cause of cancer deaths. This specific type of cancer affects women in both developed and developing countries. Prevention and early diagnosis are very important factors for good prognosis. A characteristic feature of cancer cells is the ability of unlimited cell division, which makes them immortal. Telomeres, which are shortened with each cell division in normal cells, are rebuilt in cancer cells by the enzyme telomerase, which is expressed in more than 85% of cancers (up to 100% of adenocarcinomas, including breast cancer). Telomerase may have different functions that are related to telomeres or unrelated. It has been shown that high activity of the enzyme in cancer cells is associated with poor cell sensitivity to therapies. Therefore, telomerase has become a potential target for cancer therapies. The low efficacy of therapies has resulted in the search for new combined and more effective therapeutic methods, including the involvement of telomerase inhibitors and telomerase-targeted immunotherapy

Vitamin C as a Modulator of the Response to Cancer Therapy

Ascorbic acid (vitamin C) has been gaining attention as a potential treatment for human malignancies. Various experimental studies have shown the ability of pharmacological doses of vitamin C alone or in combinations with clinically used drugs to exert beneficial effects in various models of human cancers. Cytotoxicity of high doses of vitamin C in cancer cells appears to be related to excessive reactive oxygen species generation and the resulting suppression of the energy production via glycolysis. A hallmark of cancer cells is a strongly upregulated aerobic glycolysis, which elevates its relative importance as a source of ATP (Adenosine 5′-triphosphate). Aerobic glycolysis is maintained by a highly increased uptake of glucose, which is made possible by the upregulated expression of its transporters, such as GLUT-1, GLUT-3, and GLUT-4. These proteins can also transport the oxidized form of vitamin C, dehydroascorbate, permitting its preferential uptake by cancer cells with the subsequent depletion of critical cellular reducers as a result of ascorbate formation. Ascorbate also has a potential to affect other aspects of cancer cell metabolism due to its ability to promote reduction of iron(III) to iron(II) in numerous cellular metalloenzymes. Among iron-dependent dioxygenases, important targets for stimulation by vitamin C in cancer include prolyl hydroxylases targeting the hypoxia-inducible factors HIF-1/HIF-2 and histone and DNA demethylases. Altered metabolism of cancer cells by vitamin C can be beneficial by itself and promote activity of specific drugs

Contribution of protein kinase A and protein kinase C signalling pathways to the regulation of HSD11B2 expression and proliferation of MCF-7 cells.

Contribution of the protein kinase A (PKA) and protein kinase C (PKC) signalling pathways to the regulation of 11β-hydroxysteroid dehydrogenase type II (HSD11B2) gene expression was investigated in human breast cancer cell line MCF-7. Treatment of the cells with an adenylyl cyclase activator, forskolin, known to stimulate the PKA pathway, resulted in an increase in HSD11B2 mRNA content. Semi-quantitative RT-PCR revealed attenuation of the effect of forskolin by phorbol ester, tetradecanoyl phorbol acetate (TPA), an activator of the PKC pathway. It was also demonstrated that specific inhibitors significantly reduced the effect of activators of the two pathways. Stimulation of the PKA pathway did not affect, whereas stimulation of the PKC pathway significantly reduced MCF-7 cell proliferation in a time-dependent manner. A cell growth inhibitor, dexamethasone, at high concentrations, caused a 40% decrease in proliferation of MCF-7 cells and this effect was abolished under conditions of increased HSD11B2 expression. It was concluded that in MCF-7 cells, stimulation of the PKA signal transduction pathway results in the induction of HSD11B2 expression and that this effect is markedly reduced by activation of the PKC pathway. Activation of the PKC pathway also resulted in inhibition of cell proliferation, while activation of the PKA pathway abolished the antiproliferative effect of dexamethasone. These effects might be due to oxidation of dexamethasone by the PKA-inducible HSD11B2g