Possibility of paclitaxel to induce the stemness-related characteristics of prostate cancer cells

BACKGROUND

Drug resistance poses a crucial problem in the treatment of prostate cancer. Recent studies have shown that chemotherapy agents may cause cancer cells to acquire stem cell-like properties, resulting in drug resistance and, eventually, treatment failure.

OBJECTIVES

To evaluate whether long-term paclitaxel exposure causes an increase in the stem cell-like properties of prostate cancer cells.

MATERIAL AND METHODS

Paclitaxel-resistant PC-3 cells were generated from parental PC-3 cells by treating them with increasing concentrations of paclitaxel. The expression levels of the stem cell markers NANOG, C-MYC, CD44, and ABCG2 were evaluated using quantitative real-time polymerase chain reaction (RT-qPCR). A sphere formation assay was performed to test the potential of the cells to behave as stem cells, and a wound healing assay was carried out to evaluate migration ability of the cells.

RESULTS

The expression levels of C-MYC and NANOG were significantly higher in paclitaxel-resistant PC-3 cells compared to the parental PC-3 cells. However, there was no significant increase in the expression of CD44 or ABCG2. In addition, the sphere-forming capacity and migration ability of resistant PC-3 cells were increased.

CONCLUSIONS

The results of the current study indicate that paclitaxel exposure may increase the stem cell-like properties of PC-3 prostate cancer cells.

Effects of menstrual cycle on divided attention in dual-task performance

PURPOSE

Monthly hormonal fluctuation in women causes changes in peripheral systems and central nervous system structure and functions. In this study, we investigated the effects of menstrual cycle periods in women on attention during multitasking. Single and dual task conditions were tested in different menstrual cycle periods.

MATERIALS AND METHODS

A total of forty women with regular menstrual cycles participated in this study. They were not any type of medication or hormonal treatment. Fine motor skills and Go/No-go tasks were performed on the 10th day of the late follicular phase, and then the tests were repeated on the 20th day of the late luteal phase. Fine motor tasks were performed by Annett's peg-moving test. Auditory stimuli were used in Go/No-go task. In dual tasks, both tasks were performed simultaneously.

RESULTS

There was no difference between follicular and luteal phases in single fine motor and Go/No-go task. In dual task condition Go/No-go task % error rate decreased in the luteal phase. Similarly, Go/No-go task reaction time decreased in the luteal phase. Non-dominant hand performance was increased in the luteal phase during the dual-task condition compared to the follicular phase.

CONCLUSIONS

When these results are evaluated together, declining error rates and reaction times indicates women successfully multitask in the luteal phase in dual tasks condition. This suggests that divided attention in women leads to better performance in the luteal phase than in the follicular phase.

Cytotoxic and genotoxic effects of an endemic plant of Turkey Salvia kronenburgii on breast cancer cell lines

Context

The natural products derived from plants are the important sources that can be used for breast cancer treatment. Salvia species and their derived products were recommended as potential antitumor substances.

Aim

The potential cytotoxic and genotoxic effects of Salvia kronenburgii have been investigated on breast cancer cell lines, MCF-7 and MDA-MB-231.

Materials and Methods

Determination of chemical compounds of S. kronenburgii was done using a gas chromatography coupled to time-of-flight mass spectrometry system and a dual-stage commercial thermal desorption injector. Growth inhibition of the S. kronenburgii was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and ATP viability assays. The cell death mode was detected by fluorescent dyes. Genotoxic effect of S. kronenburgii was measured by comet assay.

Results

S. kronenburgii showed antiproliferative effect in a dose-dependent manner on MCF-7 and MDA-MB-231 cell lines by inducing apoptosis-like cell death. The pyknotic cell nuclei were observed at the cell lines in response to S. kronenburgii. Furthermore, significant increase was shown in genetic damage index and frequencies in the damaged cells.

Conclusion

S. kronenburgii might be a promising natural source for cancer therapy. Further experiments need to be done in vivo to understand of the anticancer effects of this plant.

Cancer Statistics in Giresun Province, Turkey: A 12-Years Retrospective Review

AIM

The aim of this retrospective study was to analyze 6,613 diagnosed cancer cases in the Black Sea Turkish province of Giresun over a period of 12 years.

MATERIAL AND METHOD

Data of this retrospective crosssectional study was collected from 6,613 cancer patients at Prof. Dr. A. Ilhan Özdemir Education and Research Hospital between 2005- 2016. MINITAB 15 package software was used for statistical analysis. Chi-Square test and differences between two ratios significance test were used to calculate the relationship between two nominal (categorical) variables.

RESULTS

Total 6,613 cancer patient's (3,759 men, 56.8% and 2,854 women, 43.2%) average age is 66.27±17.17. The most frequent types of cancer found among men included prostate (24.4%), bronchus-lung (12.5%) and colorectal (11.15%) cancer; whilst among for women it was breast (26%), thyroid (14.9%) and skin (10.6%) cancer, respectively. Kidney, bronchus-lung, skin, larynx, breast, bladder and thyroid cancer types were determined to be statistically significant according to gender (p<0.05).

CONCLUSION

We reviewed the diagnosed cancer cases in Giresun province from 2005 to 2016. For men, the order of the most frequent cancer types mentioned is consistent with the statistics of both the European Union (EU) as well as the United States of America (USA); whereas for women it was consistent with Turkey's own national statistics. However, our findings state that thyroid cancer is the second most common cancer type among Turkish women, this is in contrast to most other parts of the world, the EU and USA.

No association of polymorphisms in the glutathione S-transferase genes with pre-eclampsia, eclampsia and HELLP syndrome in a Turkish population

AIM

There is substantial evidence that genetic factors play a role in pre-eclampsia. The aim of this study was to determine whether genetic variability in the encoding of genes for glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) contributes to individual differences in susceptibility to pre-eclampsia, eclampsia, or hemolysis, elevated liver enzymes, and low platelets (HELLP syndrome).

METHODS

A total of 221 women with pre-eclampsia, eclampsia and HELLP syndrome and 147 healthy female controls were genotyped for GSTM1 and GSTT1 polymorphisms by polymerase chain reaction (PCR). Statistical evaluation of differences in polymorphic rates was carried out using chi(2) analysis.

RESULTS

This study included 140 pre-eclamptic, 33 eclamptic and 48 HELLP syndrome cases and 147 healthy controls. The frequencies for the GSTM1 null genotype were 58%, 45%, and 60% for pre-eclampsia, eclampsia, and HELLP syndrome, respectively, and in controls it was 55%. The distribution of the GSTT1 null genotype was 22%, 21%, and 27% for pre-eclampsia, eclampsia, and HELLP syndrome, respectively, and in controls it was 22%. There was no significant association between GSTM1 and GSTT1 polymorphisms and pre-eclampsia, eclampsia, and HELLP syndrome.

CONCLUSION

Our data do not support a role for polymorphisms of the GSTM1 and GSTT1 genes in the pathogenesis of pre-eclampsia, eclampsia and HELLP syndrome.

Somatostatin receptor subtype 1 modulates basal inhibition of growth hormone release in somatotrophs

Somatostatin (SST) inhibits the secretion of many peptide hormones including growth hormone (GH). The various functions of SST are mediated through at least five different receptor subtypes (SSTR1-5), their precise physiological roles have not been solved yet. Here we report on studies concerning the functional role of SSTR1 in the modulation of GH release from somatotrophs. Primary cell cultures from pituitaries of wild-type SSTR1 mice exposed to the SSTR1 selective somatostatin analog CH-275 show reduction of basal levels of GH secretion whereas somatotrophs isolated from SSTR1 null mutant mice did not respond to the agonist-mediated effect. This suggests that SSTR1 is involved in modulating basal GH levels in primary pituitary cell cultures and, together with SSTR2, may control the secretion of GH in the body.

Palindromic DNA and genome stability. Further studies

Unusual DNA structures promote genetic instability. One such example is hairpin DNA, which can form from palindromic sequences and triplet repeats, and is also a characteristic intermediate in V(D)J recombination. We previously found that a large 15.3-kb palindrome that was introduced as a transgene into the mouse germline was highly unstable. Although it could be transmitted, the transgene was found to be rearranged in up to 56% of the progeny, and rearrangement events often involved deletion at the center of symmetry. Here, the fine structure of centrally deleted palindromes was sampled by analysis of recombinant junctions isolated from testes DNA, providing further evidence for a model, previously proposed, that accounts for such deletions on the basis of a hairpin-tip nicking activity. In addition to central deletions, gene conversion events were also elevated in the transgenic palindrome. We have now analyzed instability in two mouse sublines in which (as a result of inversion) the transgenic palindrome had been shortened to 4.2 kb. In these sublines, the transgene was still subject to both rearrangement and gene conversion events at a high frequency, similar to the original 15.3-kb palindrome. Recombination was not limited to the sequences constituting the inverted repeat, but was seen to include sequences lying outside the palindrome. As discussed, the salient feature in all of these observations, a high level of genetic change associated with palindromic DNA, underscores the significance of hairpin DNA and hairpin-tip nicking in genome stability.

Palindrome resolution and recombination in the mammalian germ line

Genetic instability is promoted by unusual sequence arrangements and DNA structures. Hairpin DNA structures can form from palindromes and from triplet repeats, and they are also intermediates in V(D)J recombination. We have measured the genetic stability of a large palindrome which has the potential to form a one-stranded hairpin or a two-stranded cruciform structure and have analyzed recombinants at the molecular level. A palindrome of 15.3 kb introduced as a transgene was found to be transmitted at a normal Mendelian ratio in mice, in striking contrast to the profound instability of large palindromes in prokaryotic systems. In a significant number of progeny mice, however, the palindromic transgene is rearranged; between 15 and 56% of progeny contain rearrangements. Rearrangements within the palindromic repeat occur both by illegitimate and homologous, reciprocal recombination. Gene conversion within the transgene locus, as quantitated by a novel sperm fluorescence assay, is also elevated. Illegitimate events often take the form of an asymmetric deletion that eliminates the central symmetry of the palindrome. Such asymmetric transgene deletions, including those that maintain one complete half of the palindromic repeat, are stabilized so that they cannot undergo further illegitimate rearrangements, and they also exhibit reduced levels of gene conversion. By contrast, transgene rearrangements that maintain the central symmetry continue to be unstable. Based on the observed events, we propose that one mechanism promoting the instability of the palindrome may involve breaks generated at the hairpin structure by a hairpin-nicking activity, as previously detected in somatic cells. Because mammalian cells are capable of efficiently repairing chromosome breaks through nonhomologous processes, the resealing of such breaks introduces a stabilizing asymmetry at the center of the palindrome. We propose that the ability of mammalian cells to eliminate the perfect symmetry in a palindromic sequence may be an important DNA repair pathway, with implications regarding the metabolism of palindromic repeats, the mutability of quasipalindromic triplet repeats, and the early steps in gene amplification events.

A model for testing recombinogenic sequences in the mouse germline

Homologous recombination is a conserved process of genetic exchange generated by homologous pairing of nucleotides. Species diversity and gene evolution are dependent on the outcomes of recombination during germ cell development, yet systems to study mammalian germline recombination, especially those with applications to human genetics, are not well developed. We report on a transgenic mouse system designed to study recombination within test sequences in the male germline utilizing an intron-interrupted lacZ reporter gene. beta-galactosidase positive sperm are detected and quantitated by flow cytometry using fluorogenic substrates. Examination of recombination within a 1.7 kb repeat of test sequences derived from the human glycophorin breakpoint cluster region detects approximately 0.04-0.09% fluorescent sperm. Confirmation that these sperm result from recombination in the germline comes from histochemical staining of testicular cells, examination of spliced mRNA, and PCR analysis of sorted sperm populations. The system is readily adaptable to studies of other sequences reported to have elevated levels of recombination, including those implicated in human genetic disease. Investigations of the molecular basis for genomic instability at specific chromosomal locations may yield important insights into mechanisms of chromosomal loss and rearrangements.

Development of collaterals in intermittent and permanent ischemia of the liver

The ischemia caused by the hepatic dearterialization as therapy for hepatic malignancies is transient because of the rapid formation of collaterals. In order to prevent this transient repeated ischemia has been suggested. An experimental study was planned to compare the collateral occurrence in persistent ischemia and transient repeated ischemia of the liver. Fourteen dogs (seven persistent ischemia, seven transient repeated ischemia) were used in this study. Hepatic dearterialization were performed in both groups. In the first group (persistent ischemia), the hepatic artery was ligated proximal to the gastroduodenal artery. In the second group (transient repeated ischemia), the hepatic artery was occluded externally in the same region as the first group by means of a device modified from 8 guage Foley catheter and after occlusion for one hour it was reopened. Occlusions were repeated twice in a day. Five dogs in the first group and six dogs in the second group completed a three week ischemia period and angiography were then performed in all. The dogs were sacrificed after the angiography and examined for possible abscess formation, arterial thrombosis, peritoneal adhesions and liver necrosis. After angiography, the two groups were also examined for collateral occurrence. Only one collateral occurred in the transient repeated ischemia group, but in the persistent ischemia group, collaterals occurred in all dogs. This difference between two groups is statistically significant (Fischer Absolute Chi Square Test, p = 0.013). Transient repeated ischemia is superior to persistent ischemia because of fewer collaterals, but in practise, total dearterialization of the liver is impossible.

Binding potency of 6-nitroquipazine analogues for the 5-hydroxytryptamine reuptake complex

The in-vitro inhibition constants (Ki) of nine structural analogues of the potent 5-hydroxytryptamine (5-HT)-uptake inhibitor, 6-nitroquipazine, were determined to assess the structure-affinity relationship of these derivatives. The goal of these studies was to determine those positions on 6-nitroquipazine that could be derivatized without significantly decreasing the affinity of the drug for the binding site, so that radiolabels such as 123I, 76Br or 18F might be appended for in-vivo imaging studies of the 5-HT reuptake system. Using bromine as a steric probe, the rank order of potency of bromine-substituted 6-nitroquipazine analogues for inhibiting the binding of [3H]paroxetine to the 5-HT reuptake binding site was: 8- < 3- < 7- < 4- < 5-bromo. The in-vitro equipotent molar ratio (EPMR, Ki (analogue)/Ki(6-nitroquipazine)) of the 5-bromo analogue was 0.57, indicating that this analogue had greater affinity for the 5-HT reuptake complex than 6-nitroquipazine. Derivatization at the 5-position with fluorine and iodine also resulted in potent compounds with EPMR values of 1.1 and 0.83, respectively. Substitution of quipazine with bromo, cyano, and formyl groups at the 6-position produced less potent compounds than the 6-nitro group. Based upon the high affinities of the 5-bromo-, 5-fluoro- and 5-iodo-6-nitroquipazines for the 5-HT reuptake complex, these compounds are candidates for radiolabeling for in-vivo studies of the 5-HT reuptake site.

Determinants of retrovirus gene expression in embryonal carcinoma cells

The expression of Moloney murine leukemia virus is restricted in embryonal carcinoma (EC) cells. To characterize specific mutations necessary for expression of retroviruses in EC cells, we analyzed the expression of retrovirus mutants and recombinants thereof in EC cell lines F9 and PCC4. DNA sequence comparison and functional studies allowed us to define three point mutations in the enhancer region of the viral mutants at positions -345, -326, and -166 and two point mutations within the 5'-untranslated region of the viral genome at positions +164 and +165 that were essential for retrovirus expression in EC cells. DNA fragments derived from either the wild type or mutant viruses were used to search for sequence-specific DNA-binding factors in nuclear extracts from undifferentiated PCC4 cells. A cellular factor was found to bind strongly to sequences within the enhancer region (-354 to -306) of wild-type viruses but only weakly to sequences derived from mutant viruses. This factor was named ECF-I (for EC cell factor I). Retroviral expression in EC cells correlates with decreased binding affinity for ECF-I.

Embryonic stem cell virus, a recombinant murine retrovirus with expression in embryonic stem cells

The expression of Moloney murine leukemia virus and vectors derived from it is restricted in undifferentiated mouse embryonal carcinoma and embryonal stem (ES) cells. We have developed a retroviral vector, the murine embryonic stem cell virus (MESV), that is active in embryonal carcinoma and ES cells. MESV was derived from a retroviral mutant [PCC4-cell-passaged myeloproliferative sarcoma virus (PCMV)] expressed in embryonal carcinoma cells but not in ES cells. The enhancer region of PCMV was shown to be functional in both cell types, but sequences within the 5' untranslated region of PCMV were found to restrict viral expression in ES cells. Replacement of this region by related sequences obtained from the dl-587rev retrovirus results in MESV, a modified PCMV virus that confers G418 resistance to fibroblasts and ES cells with similar efficiencies. Expression of MESV in ES cells is mediated by transcriptional regulatory elements within the 5' long terminal repeat of the viral genome.

[Occlusion of the gastric outlet caused by a trichobezoar]

Bezoars are concretions formed in the gastrointestinal tract. The trichobezoars are hairballs in the stomach or intestines composed of hair. They are usually found in young girls as in our case which we operated in April 1989 on Surgical Ward in Kartal State Hospital in Istanbul. The postgastrectomy state predisposes to bezoar formation. Persimmon peels or pits, orange or grapefruit pulp are the usual offenders. Bezoars are associated with vague upper gastrointestinal discomfort, nausea, and vomiting. The patients may complain of abdominal pain. Ulceration, bleeding, obstruction, and perforation are the most common complications. Treatment consist of mechanical fragmentation via the endoscope or operative extraction. Dissolution of the undigested bolus by ingestion of proteolytic enzymes such as papain may be tried. As prophylaxis the postgastrectomy patient must be warned of ingesting citrus fruits.