Increase In S-phase Fraction Research Articles

S-phase – an independent prognostic marker in upper tract urothelial carcinoma

Objectives To evaluate S-phase fraction as a predictor of invasiveness and cancer-specific survival in upper tract urothelial carcinoma (UTUC). Patients and methods One hundred and fifteen patients having undergone radical nephroureterectomy were analysed with histology in radical nephroureterectomy specimens as reference test and S-phase fraction as index test. Ploidy and S-phase were determined using flow cytometry. Differences in S-phase fraction were calculated between stages, grades (WHO 1999 and 2004 classifications), ploidy and patients that died of UTUC and those who did not. Five- and 10-year-cancer-specific survivals were calculated. Areas under the ROC curve (AUCs) of S-phase fraction in relation to tumour stage and to death from UTUC were measured. Multiple Cox regression was performed. Results Independent prognostic markers of death from UTUC were S-phase fraction and stage. Correlation between S-phase fraction and risk of dying from UTUC was strong, with a 17% greater risk of death from UTUC with every 1% increase in S-phase fraction, hazard ratio = 1.17, 95% CI = 1.10–1.25, p < 0.001, Spearman’s rho ρ = 0.65. AUCs for S-phase fraction as predictors of stage and death from UTUC were 0.8 (95% CI = 0.705–0.894) and 0.77 (95% CI = 0.67–0.87), respectively. Cancer-specific survival was statistically significantly different between stages, ploidy and WHO 1999 grades, but not between WHO 2004 grades. This was also reflected in S-phase fraction, which differed in LG-G1 compared with LG-G2 and in HG-G2 compared with HG-G3. Conclusion S-phase fraction was a good test for predicting both invasiveness and cancer-specific survival. Using both WHO 1999 and 2004 classifications, rather than one system alone, had a higher predictive value of cancer-specific survival.

Effect of Dietary Advanced Glycation end Products on Cell Cycle of Peripheral Blood Lymphocytes

Advanced glycation end products (AGEs) have been linked with autoimmune diseases. AGEs present in diet are known to be absorbed intestinally. We aimed to study effects of dietary AGEs present in repeatedly heated cooking oil on cell cycle profile of lymphocytes derived from healthy volunteers. AGEs were extracted by using Aqueous-TCAChloroform method and incubated with lymphocytes for 24 hours. All extracts showed ASF (15.42-75.18) between 355-440 nm wavelength. On incubation with AGEs, an increase in S-phase fraction of treated lymphocytes (7.67 ± 3.25) was observed in 10/10 samples analysed as compared to untreated lymphocytes (1.5 ± 1.6). The results suggest that dietary AGEs may have a role in triggering the proliferation of lymphocytes. Larger studies are required to explore role of dietary AGEs on properties of lymphocytes which may contribute to etiopathogenesis of autoimmune diseases. Such studies may provide us with a modifiable risk factor which may be altered to prevent autoimmune diseases.

Androgen receptor expression is a biological marker for androgen sensitivity in high grade serous epithelial ovarian cancer

ObjectivesIn the present study we explore the effects of androgens and anti-androgens on primary cultures of EOC cells. We also investigate the effects of chemotherapy on AR expression. Epithelial ovarian cancer (EOC) arises from ovarian surface epithelial cells (OSE), which express the androgen receptor (AR). Androgen stimulation of OSE cells results in increased proliferation and protection from apoptosis. Nevertheless, in clinical trials anti-androgens have had a low objective response rate in relapsed ovarian cancer. Methods1. Androgen receptor (AR) expression and response to androgenic stimulation were correlated in primary ovarian cancer cells derived from ascitic fluid from patients with advanced ovarian cancer,2. AR expression in primary epithelial ovarian cancer was investigated before and after chemotherapy using paired histological samples which had been incorporated into a tissue microarray. ResultsEleven primary ovarian cancer cultures were established from ascitic fluid. There was wide variation of expression of androgen receptor mRNA between cultures. Cell division increased after dihydro-testosterone (DHT) stimulation in 6 out of 11 primary cultures. The fraction of cells in S-phase increased from 4.4% in cells grown in serum-free medium to 8.3% in cells stimulated with 100nM of DHT (P<0.001). The increase in S-phase fraction was abrogated after treatment with the anti-androgen, bicalutamide in 4 out of 5 responsive cultures. There was a strong correlation (r2=0.7) between nuclear AR expression by immunohistochemistry and S-phase fraction changes in primary cultures.Paired pre- and post-chemotherapy histological samples from 29 patients were incorporated into a tissue microarray (TMA). Nuclear and cytoplasmic AR expression by immunohistochemistry (IHC) decreased significantly after chemotherapy (P<0.01). ConclusionAR expression correlates with increased S-phase fraction in response to androgenic stimulation. Immunohistochemical analysis of AR expression needs to be further tested in clinical trials to select AR positive EOC for anti-androgen therapy. Anti-androgen use early in the course of ovarian cancer is more likely to be effective as these data suggest that androgen receptor expression decreases with exposure to chemotherapy and this may explain the low response rates seen in clinical trials of patients heavily pre-treated with multiple courses of chemotherapy.

Androgen-related expression of G-proteins in ovarian cancer

Background:Epidemiological and in vitro data implicate androgens in the aetiology of ovarian cancer, but the mechanisms by which this is mediated are unclear. In this study, we wished to examine the effects of androgens on gene expression in ovarian cancer.Methods:The expression of androgen receptor (AR) in OVCAR3 and OSEC2 cells was confirmed using immunoblotting and response to androgens was measured using flow cytometric assessment of S-phase fraction. The differential gene expression between androgen stimulated and unstimulated OVCAR3 ovarian cancer cells was examined with a cDNA microarray. The upregulation of a subset of these genes was then confirmed with reverse transcriptase PCR in both OVCAR3 and OSEC2, an ovarian epithelial cell line. Finally, the clinical significance of this upregulation was investigated by examining the expression of Rab25 and Rab35, two G-protein-related molecules in an ovarian cancer tissue microarray (TMA).Results:OVCAR3 and OSEC2 cells were shown to express the AR and showed an increase in S-phase fraction in response to androgen treatment. Treatment of OVCAR3 cells with androgen resulted in a significant upregulation of 121 genes. These findings were confirmed for a subset of seven monomeric G-protein-related genes in both OVCAR3 and OSEC2 cells. After staining for Rab25 and Rab35, the majority of TMA sections examined showed expression for Rab25 (92%) and Rab35 (95%). The expression of Rab25 correlated with histological grade, and expression was higher in endometrioid (median histoscore 10.5) than serous (7.5) or mucinous (5.3) tumours. The expression of Rab25 correlated positively with AR expression supporting its role as an androgen responsive gene in ovarian cancer.Conclusions:These results suggest that androgens can effect expression of the oncogenic GTPases in ovarian cancer. We propose that the androgen responsive Rab35 may have clinical importance as a biomarker of AR function.

Cyclin E deregulation alters the biologic properties of ovarian cancer cells.

We have previously shown that the low molecular weight (LMW) forms (trunk 1 and trunk 2) of cyclin E are biochemically hyperactive and induce G1/S progression in normal epithelial cells. Here we investigate the biologic consequences of LMW cyclin E expression in ovarian cancer cells. Using a panel of ovarian carcinoma tumors we find that cyclin E overexpression is invariably due to the presence of LMW forms and that expression of these forms appears to correlate with more advanced grade and stage of disease. Despite similar expression of p21 and p27, cyclin E overexpressing tumors have higher kinase function. Using an isogenic ovarian cancer model, we find that clones that overexpress the trunk 1 (T1) protein have a 10-fold increase in cyclin E kinase function, a 20% increase in S-phase fraction, a 10-15% decrease in doubling time and a 20% increase in colony formation compared to parental cells that express only the FL cyclin E protein. T1 clones were resistant to G1 arrest but more sensitive to cisplatin. Therefore, in ovarian tumors, the presence of LMW cyclin E forms confers altered biologic properties. Our data provides a potential mechanism for the poor prognosis of patients with LMW cyclin E expressing tumors.

Evaluation of damage to the testicular cells of golden hamsters caused by experimental cryptorchidism using flow cytometry and confocal microscopy.

Artificial unilateral cryptorchidism was performed in golden hamsters which were then held for different periods of time. The non-operated side was used as a control. At various times from 4 to 15 days, hamsters were killed, testes were removed and weighed, single cell suspensions were prepared for flow cytometry analysis and seminiferous tubules were fixed for confocal microscopy. Using DNA staining by propidium iodide or acridine orange followed by flow cytometry analysis, a marked decrease in the haploid condensed cell fraction was detected at the beginning stages of experimental cryptorchidism. In correlation with flow cytometry results, spermiogenic arrest at stages IX and X of seminiferous epithelium was detected in these animals by confocal microscopy and there were no mature forms of haploid cells in the cryptorchid testis. In the testis with more severe damage, there were almost no haploid cells in the seminiferous tubules of cryptorchid animals. In addition, a significant decrease in tetraploid cell fraction and an increase in S-phase fraction was obtained in severe cases. This may be explained by cell arrest before entrance into meiosis. Destruction of tubule structure and cell arrangement were also observed by confocal microscopy in such cases. In conclusion, flow cytometry, combined with confocal analysis, added useful information about spermatogenesis disturbances in cryptorchid testis and it may be used as diagnostic tools in other cases of spermatogenic disorders.

ACIDIC FIBROBLAST GROWTH FACTOR (FGF 1) INCREASES SURVIVAL AND HAEMATOPOIETIC RECOVERY IN TOTAL BODY IRRADIATED C 3H/HeNCr MICE

Basic fibroblast growth factor is known to stimulate the proliferation of bone marrow stem and/or progenitor cells in vitro and in vivo. We examined a similar cytokine, acidic fibroblast growth factor (FGF 1), for its in vivo radiomodifying effects. Female C 3H/HeNCr mice were given human recombinant FGF 1intravenously at doses ranging from 1 to 24 μg. FGF 1was delivered in two equal doses 24 and 4 h before or 24 h after otherwise lethal total body irradiation (TBI). In vivo FGF 1radioprotection of C 3H mice was maximized at a total dose of 12 μg/mouse given before TBI. The radiomodification was 1.16 ± 0.03 (±1 SD) with an increase of LD 50/30from 736 ± 9 to 854 ± 16 cGy ( P< 0.01). Some retroactive radiomodification was observed even when FGF 1was given 24 h after irradiation ( P< 0.05). FGF 1radioprotected mice by improving the repopulation of haematopoietic progenitor cells of bone marrow. The radioprotection was not associated with an increase in S-phase fraction or detectable circulating IL-3, TNF-α or GM-CSF, suggesting that other mechanisms of protection were responsible.

Effects of selected chemotherapeutic agents on PCNA expression in prostate carcinoma cell lines.

Bivariate flow cytometric analysis of proliferating cell nuclear antigen (PCNA) was performed on prostate carcinoma cell lines (PC-3, DU-145). For both cell lines 100% methanol fixation provided optimal fluorescence intensity of PCNA. The ratio of PCNA/DNA increased in late G1 through early S/phase, followed by a decrease in mid- and late S and enhancement in G2/M phase. PCNA expression was increased in G2/M phase cells treated for 48 h with vinblastine. A slight decrease in PCNA expression was observed with cyclohexamide treatment. Hydroxyurea induced an increase in S-phase fraction along with enhanced PCNA expression. Methotrexate and Adriamycin had little effect on the cell cycle compartments of PC-3 or DU-145; however, methotrexate decreased PCNA expression, while Adriamycin enhanced it. Cisplatin increased S-phase in both cell lines, increasing PCNA expression in PC-3 and decreasing it in DU-145 cells. The data on the effects of drug treatment point to a dissociation between PCNA expression and S-phase fraction as calculated from the DNA distribution. In some cases, e.g., the cisplatin studies, different effects were obtained in the two different cell lines treated with the same drugs. Whether changes in PCNA expression will provide more useful information than S-phase fraction for evaluation of potential antitumor drugs is not known.

DNA ploidy level and S-phase fraction as prognostic factors in breast cancer

Imprint smears from sixty cases of breast cancer made after mastectomy were stained by the Feulgen method and the nuclear DNA content measured by a cytofluorometer equipped with an incident illumination system. After logarithmic transformation of the fluorescence intensity, the ploidy level and S-phase fraction (SPF) were calculated with a microcomputer and the correlation between the ploidy level or SPF and the clinicopathological prognostic factors studied. Patients with tumors of a larger diameter and more extensive lymph node involvement had higher levels of ploidy and SPF and the ploidy level in the metastatic lymph nodes was higher than that in the primary lesion. Moreover, a significant increase in SPF was observed in the metastatic lymph nodes and a high ploidy level found to be associated with tumors having a negative estrogen receptor. When the tumors were divided into a diploid group and an aneuploid group, the diploid group showed a significantly better prognosis than the aneuploid group, in 6-year survival. Similarly, the groups in which SPF was less than 20.0 per cent had significantly better prognoses than the group in which SPF was 20.1 per cent or more. These prognostic factors were evaluated with Cox's proportional hazard model and a significant correlation observed in lymph node status, ER status, ploidy level and S-phase fraction. It was thus concluded that ploidy level and SPF are important and independent prognostic factors for predicting the postoperative course of breast cancer patients.

Cell proliferation and 3H-proline incorporation in periodontal ligament exposed to mechanical stress

In order to study the metabolic processes induced in the periodontal ligament by mechanical influences, a tension spring was implanted in rats between the incisor and the first maxillary molar on the right-hand side, while the left maxilla of these animals as well as non-operated rats served as controls. Under such mechanical stress, there occurred at 3, 10 and 21 days after implantation a significant increase in the 3H-thymidine labeling index, which was demonstrable histoautoradiographically. A change in cell density was not discovered. Therefore, the increase in S-phase fraction as equally recorded in both pressure and tension zones is regarded as an expression of an enhanced cell turnover. Cell renewal in the periodontal ligament can be modified by inflammatory processes within the gingival region. There is a slight enlargement of the periodontal space in the tension zone. Under our experimental conditions, no change occurs in the silver grain number per cell after 3H-proline administration. The results indicate that, following the impact of orthodontic forces, the reactivity of periodontal cell proliferation as compared to collagen synthesis is enhanced.