Serotonin and melatonin do not play a prominent role in the growth of prostate cancer cell lines.

OBJECTIVES: To investigate the effects of serotonin and melatonin (MLT) on the regulation of malignant growth and the activity of serotonin receptors (5HTR1a/-1b) in prostate cancer (PCa) cell lines. MATERIALS AND METHODS: In four PCa cell lines (LNCaP, 22RV1, PC3, DU145) and two reference cell lines 5HTR1a and -1b, relative mRNA expression levels were assessed. Different serotonin and MLT receptor agonists and antagonists were used in stimulation and inhibition experiments. RESULTS: mRNA expression of 5HTR1b was higher than that of 5HTR1a in all PCa cell lines. Serotonin showed a significant growth stimulatory effect in all PCa lines. The 5HTR1a and -1b agonists/antagonists did not significantly affect viability. MLT inhibited viability only in PC3 cells. Similarly, the 5HTR1a antagonist induced apoptotic changes in PC3 cells only at 10(-4)M, while the 5HTR1b antagonist induced necrosis at 10(-4)M in all cell lines. Cell cycle alterations were seen in PC3 and DU145 cells under the influence of the 5HTR1a antagonist. CONCLUSIONS: Serotonin receptor antagonists and agonists as well as MLT influence viability and apoptosis of PCa cell lines at supraphysiologic concentrations. In contrast to other reports, our results do not support a regulatory role of serotonin or MLT receptor activation or inhibition in PCa growth.

Co-detection of members of the urokinase plasminogen activator system in tumour tissue and serum correlates with a poor prognosis for soft-tissue sarcoma patients.

BACKGROUND: The urokinase plasminogen activator (uPA) system is one of the best-investigated protease systems, both under physiological and pathological conditions, including various types of cancer. However, effects of co-expression of members of the uPA system in soft-tissue sarcoma (STS) patients at the protein level in both tumour tissue and serum have not been investigated yet. METHODS: We examined 82 STS patients for protein levels of uPA, PAI-1and uPAR in tumour tissue and serum by ELISA. RESULTS: A significant correlation between high antigen levels of uPA, PAI-1 or uPAR in tumour tissue, and of uPAR in serum, with poor outcome of STS patients was found for the first time. Most strikingly, we observed an additive effect of combined uPA, PAI-1 or uPAR levels in tumour tissue extracts with uPAR levels in serum on patients' prognosis. High uPA/uPAR, PAI-1/uPAR and uPAR/uPAR antigen levels in tumour tissue/serum were associated with a 5.9-fold, 5.8-fold and 6.2-fold increased risk of tumour-related death (P=0.003, 0.001 and 0.002, respectively) compared with those patients who displayed low levels of the respective marker combination. CONCLUSION: As expression of members of the uPA system in tumour tissue and serum is additively correlated with prognosis of STS patients, our results suggest that combinations of these biomarkers can identify STS patients with a higher risk of tumour-related death.

Stem cell-associated genes are extremely poor prognostic factors for soft-tissue sarcoma patients.

Cancer stem cells can play an important role in tumorigenesis and tumor progression. However, it is still difficult to detect and isolate cancer stem cells. An alternative approach is to analyse stem cell-associated gene expression. We investigated the coexpression of three stem cell-associated genes, Hiwi, hTERT and survivin, by quantitative real-time-PCR in 104 primary soft-tissue sarcomas (STS). Multivariate Cox's proportional hazards regression analyses allowed correlating gene expression with overall survival for STS patients. Coexpression of all three stem cell-associated genes resulted in a significantly increased risk of tumor-related death. Importantly, tumors of patients with the poorest prognosis were of all four tumor stages, suggesting that their risk is based upon coexpression of stem cell-associated genes rather than on tumor stage.

Are overexpressed alternative survivin transcripts in human bladder cancer suitable targets for siRNA-mediated in vitro inhibition?

In order to reduce side effects of survivin-inhibiting anticancer therapies, we determined the expression of the survivin transcripts survivin-wild-type (survivin-wt), survivin-DeltaEx3 (DeltaEx3) and survivin-2B (2B) in cryo-preserved tumor and non-malignant bladder tissues (18 tumor and 22 non-malignant samples, including 17 autologous tissue pairs) by quantitative PCR. Furthermore, we investigated the biological effects following specific inhibition of the alternative transcripts DeltaEx3 and 2B in bladder cancer (BCa) cells. In BCa and non-malignant bladder tissues survivin-wt was the quantitatively dominant transcript followed by DeltaEx3 and 2B. The mean mRNA expression of DeltaEx3 (0.37 vs. 0.06 zmol/amol GAPDH, respectively) and 2B (0.13 vs. 0.01 zmol/amol GAPDH, respectively) was significantly higher in BCa compared to non-malignant bladder tissues, indicating their accessibility for an expression inhibition in BCa cells. Effective and long-lasting small interfering RNA-mediated inhibition of one alternative survivin transcript caused lower cell growth reduction effects (apoptosis induction, cell cycle arrest, colony formation) compared to simultaneous inhibition of multiple survivin transcripts including survivin-wt. Inhibition of one alternative survivin transcript increased the apoptosis rate by 11% vs. 33-46% when reducing several survivin transcripts. We observed no G2/M arrest or reduction of cell colony formation after inhibiting one alternative survivin transcript. Reduction of cell viability by the chemotherapeutics cisplatin, mitomycin C or gemcitabine was stronger in combination with inhibition of several survivin transcripts than in combination with the reduction of one alternative survivin splice variant. Furthermore, reducing one alternative transcript caused chemosensitization to only one chemotherapeutic agent in contrast to inhibition of several survivin transcripts. Therefore, the alternative survivin transcripts DeltaEx3 and 2B do not represent reasonable targets for anticancer, at least BCa, treatment.

Expression of the stem cell self-renewal gene Hiwi and risk of tumour-related death in patients with soft-tissue sarcoma.

Self-renewal is considered as a common property of stem cells. Dysregulation of stem cell self-renewal is likely a requirement for the development of cancer. Hiwi, the human Piwi gene, encodes a protein responsible for stem cell self-renewal. In this study, we investigated the expression of Hiwi at the RNA level by real-time quantitative PCR in 65 primary soft-tissue sarcomas (STS) and ascertained its impact on prognosis for STS patients. In a multivariate Cox's proportional hazards regression model, we found that an increased expression of Hiwi mRNA is a significant negative prognostic factor for patients with STS (P=0.017; relative risk 4.6, 95% confidence interval (CI) 1.3-16.1) compared to medium expression of Hiwi transcript. However, a low expression of Hiwi transcript is correlated with a 2.4-fold (CI 0.7-8.0) increased risk, but this effect was not significant (P=0.17). Altogether, high-level expression of Hiwi mRNA identifies STS patients at high risk of tumour-related death. This is the first report showing a correlation between expression of a gene involved in stem cell self-renewal and prognosis of cancer patients.

Expression of cathepsin B, D and L protein in juvenile idiopathic arthritis.

Juvenile idiopathic arthritis (JIA) is the most common childhood autoimmune rheumatic disease and like rheumatoid arthritis (RA), it is characterized by inflammation and the progressive destruction of joints. In RA, cathepsins as proteinases play a major role in destroying synovial tissue and cartilage matrix. So far no data on cathepsin expression in pannus tissue of HA patients exist. The aim of this study was to characterize the expression levels of cathepsins B, D, H, and L in HA and to compare them with those in RA. Synovectomy tissue from 16 HA and 12 RA patients was investigated for cathepsin expression levels by Western blot analysis. Expression of cathepsins B, D and L was on comparable levels in the synovectomy tissue of HA and RA patients. The following graduation of expression was determined: cathepsin D > cathepsin L > cathepsin B. Cathepsin H was neither found to be expressed in HA nor in RA patients. The expression levels of cathepsins in pannus tissue showed no clear difference between patients with systemic JIA and patients with monoarticular JIA. In summary, the comparable expression of cathepsins B, D and L in RA and JIA synovectomy tissue suggests that they may play a similarly important role in destroying synovial tissue and cartilage matrix in the course of HA and RA.

LOH analyses in the region of the putative tumour suppressor gene C13 on chromosome 13q13.

BACKGROUND: In previous studies we isolated a new cDNA fragment named C13 which is down-regulated in malignant prostate tissues. The corresponding gene is localized on chromosome 13q13 between the known tumour suppressor genes (TSG) BRCA-2 and RB-1. MATERIALS AND METHODS: Loss of heterozygosity (LOH) analyses were carried out in the region of C13 in order to investigate the importance of the new putative TSG for prostate cancer development. Using semiquantitative LOH analysis, we screened 21 prostate carcinoma patients of different tumour stages (pT2-pT4) for 14 microsatellite markers in the region of C13 (13q13) and in the flanking BRCA-2 and the RB-1 loci. RESULTS: For 18 (86%) patients LOH or allelic imbalances were found. We identified three to nine alterations in affected tumours per marker. An overall genetic alteration frequency per patient of 38% (86 of 225 informative cases) could be calculated. One important finding regarding the overall frequency of determined microsatellite instability is that the LOH/AI rate of 47% for the seven C13-associated markers was higher than for the four markers of the RB-1 locus (39%) and for the three BRCA-2 markers (25%). Surprisingly, defining LOH critical regions (LCR) for the investigated marker panel, eight of the ten affected LCR cases showed chromosomal imbalances simultaneously for the RB-1 and the C13 LOH markers. CONCLUSIONS: The high LOH rate for eight different microsatellite markers in and around the putative TSG locus C13 on chromosome 13q13 further supports an involvement of C13 in prostate tumourigenesis.

Increased survivin transcript levels: an independent negative predictor of survival in soft tissue sarcoma patients.

Survivin, a recently identified inhibitor of apoptosis protein (IAP), is expressed in diverse embryonic tissues and in various human cancers. We have investigated the quantitative expression of survivin mRNA by a sensitive TaqMan-based RT-PCR assay in tissue samples from 94 patients with soft tissue sarcomas (STS). Survivin transcript levels were measured and normalized to GAPDH transcripts. By using a multivariate Cox regression analysis, we found an inverse correlation between the level of survivin mRNA (ratio >2 zmol survivin/amol GAPDH) and the rate of overall survival (p = 0.009, RR = 2.7). Survivin transcript variants as detected by qualitative RT-PCR analysis were revealed in 36 of 56 STS patients (64%). Only survivin DeltaEx3 and/or full-length survivin variants but not survivin 2B were identified. Our results suggest that a higher level of survivin mRNA is an independent predictor of survival for STS patients.

Radiosensitization in sarcoma cell lines with a p53 missense mutation correlates with prevention of irradiation G2/M arrest but not with induction of apoptosis.

We analysed the effects of caffeine and taxol on the radiobiological behaviour of two human sarcoma cell lines (RD, SK-LMS-1) each with a p53 missense mutation. Treatment with 2 mM caffeine resulted in an inhibition of the irradiation induced G2/M arrest in both cell lines. This effect was coupled with a radiosensitization in cell line SK-LMS-1 after an irradiation with 6 Gy (enhancement factor of 5.0). However, the effect of radiosensitization was not correlated with an induction of apoptosis. Incubation with 20 nM taxol increased the irradiation induced apoptosis almost 3-fold in cell line SK-LMS-1, but not in cell line RD. However, taxol had no effect on the irradiation induced G2/M arrest or radiosensitivity in either cell line. The results support the hypothesis that the prevention of irradiation induced G2/M arrest but not the induction of apoptosis plays a critical role in determining radiosensitivity in sarcoma cell lines with p53 mutations.

Transfection with mdm2-antisense or wtp53 results in radiosensitization and an increased apoptosis of a soft tissue sarcoma cell line.

Soft tissue sarcomas (STS) are mostly resistant after radiation treatment and are characterized by a rather low rate of apoptosis. The aim of this study was to test, in the p53 mutant STS cell line US8-93, the effect of a combined treatment with DNA transfection--either with mdm2 antisense oligodesoxynucleotides (mdm2-AS) or with a wild-type p53-plasmid (wtp53)--and the effects of irradiation on radiosensitivity. Mdm2-sense oligodesoxynucleotides (mdm2-SE) and a GFP-plasmid (GFP) were applied as controls. In order to evaluate the treatment radiation sensitization (clonogenic survival), apoptotic cell death and P53/MDM2-protein expression were determined. A moderately increased radiation sensitization was observed when comparing clonogenic survival after 2 Gy irradiation between cells transfected either with the control mdm2-SE (48%) or with mdm-2 AS (30%). At the same irradiation dose, clonogenic survival of wtp53-plasmid transfected cells (32%) was about 2-fold less than in the cells transfected with the control GFP-plasmid (61%). This enhancement factor of radiation sensitization was increased by about 3-fold at 4 Gy irradiation. Furthermore, an increase in apoptotic cells was already detectable by up to 7.7% (mdm2-AS) in comparison to 3.1% (mdm2-SE control) 72 hours after transfection. In parallel, the percentage of apoptotic cells could be further elevated after subsequent irradiation with 12 Gy by up to 15% (mdm2-AS) compared to 5.7% (mdm2-SE control). A striking result was obtained with the combined treatment of a wtp53 and 12 Gy irradiation which produced in 25% and 38.9% of apoptotic cells 48 hours and 72 hours after transfection, respectively. We can therefore conclude that the sensitivity of radiation therapy is enhanced by DNA transfection with wtp53 or mdm-2 AS ODNs for the correction of the p53-mdm2 balance in STS in vitro.

Low detection rate of p53 antibodies in sera of soft tissue sarcoma patients.

Accumulation of the p53 gene product can lead to its immunogenic appearance and the generation of p53 serum antibodies (p53ab). In different cancer types the occurrence of detectable p53ab has an independent prognostic impact. In spite of the known p53 protein overexpression rate in soft tissue sarcomas (STS), up to 70%, there have been no investigations done on p53ab in serum in STS patients. In this prospective study of 50 STS patients, we investigated the presence of serum p53ab using an enzyme-linked immunosorbent assay system and the presence of p53 overexpression in the appropriate tissue specimen immunohistochemically. Using Kruskal-Wallis chi(2) and Kaplan-Meier tests the results were then correlated to histopathological and clinical data. Six of the 50 patients (12%) showed p53ab detectable in the serum, and 56% (28/50) of the tumors were p53 immunohistochemically positive. Four of the six p53ab positives (66%) had immunohistochemically p53 positive and two (33%) had negative tumors. Altogether four of the 50 patients (8%) were positive for p53ab in serum as well as for p53 immunohistochemistry in tumor tissue specimens. Twenty patients (40%) were negative for both. All of the p53ab positive patients had stage I or II tumors. Excluding tumor stage there was no p53ab correlation to histopathological, clinical or prognostic parameters. We conclude that in STS patients, p53ab also occurs but in contrast to other tumor types at a relatively low frequency. According to our results, the clinical value of p53ab seems to be limited in STS patients.

Human telomerase reverse transcriptase antisense treatment downregulates the viability of prostate cancer cells in vitro.

Telomerase, a ribonucleoprotein complex is activated in the vast majority of human malignancies, including prostate cancer. Its inhibition is a putative way to affect cancer proliferation and might be used in the therapy of tumors. We analysed the influence of antisense phosphorothioate oligonucleotides (PTO) against the reverse transcriptase subunit of telomerase on prostate cancer cell viability, telomerase activity and telomere length. DU145 prostate cancer cells were cultivated in PTO containing medium. The PTO-incorporation was confirmed by confocal laser scanning microscopy. Cell viability was measured by a WST-1 tetrazolium assay. After 15 days of antisense PTO treatment, a significant inhibition of cell viability occurred. Telomerase activity was determined by a telomeric repeat amplification protocol (TRAP) assay and telomere length by Southern blot analysis. Since the long-term telomerase antisense treatment reduces the viability of prostate cancer cells significantly, this antisense approach could be a new therapeutic strategy to treat patients with advanced prostate cancer.

Loss of G2/M arrest correlates with radiosensitization in two human sarcoma cell lines with mutant p53.

We have examined the modulation of radiosensitivity by using caffeine in two human sarcoma cell lines both with a p53 mutation (US8-93 and LMS6-93). In both cell lines a strong irradiation-induced G2/M arrest was coupled with a low rate of apoptosis. Incubation with caffeine resulted in a low percentage of S and G2/M cells, associated with an accumulation in G1. With a higher caffeine concentration, we detected a lower clonogenic survival with IC(50) at 2 mM. In both cell lines incubation with caffeine completely prevents the irradiation-induced G2/M arrest. This was connected to radiosensitization, but without direct correlation to an induction of apoptosis. The effect of radiosensitization rose with higher irradiation doses. However, in comparison with LMS6-93, it was stronger in cell line US8-93. A higher radiosensitization in US8-93 correlated with the prevention of strong irradiation-induced G2/M response and higher initial DNA damage. Results of Western hybridization reveal a p53-independent mechanism of radiosensitization caused by caffeine. Our findings suggest that modulation in G2/M regulation may affect a common checkpoint for tumor cells with defective p53 function. Furthermore, our results show that the enhancer effect of caffeine is dependent on a strong reduction in the number of G2/M arrested cells and on an inhibition of DNA damage repair after irradiation.

Detection and enrichment of disseminated renal carcinoma cells from peripheral blood by immunomagnetic cell separation.

We have established an immunomagnetic separation procedure for the detection of circulating tumor cells in the peripheral blood based on the magnetic cell sorting (MACS) technique. In previous in vitro experiments, renal-cell carcinoma (RCC) cells were mixed with peripheral blood. In dilutions of 1:200 to 1:107 tumor cells per mononuclear blood cells, an average recovery rate of 84% of tumor cells was determined. In our study, 104 peripheral blood samples from 59 renal carcinoma patients were analyzed. MACS resulted in significant depletion of leukocytes, permitting a search for tumor cells on just 1 slide. Analyzing 8 ml of peripheral blood per patient, 19/59 RCC patients carried disseminated tumor cells (32%) in the range of 1 to 38 cells (median 8). Interestingly, for the cytokeratin-positive (CK+) patient group, we found a correlation between tumor cell number and grading (G2 vs. G3) and an increased number of CK+ patients with advanced tumor stage. MACS appears to be an efficient technique to detect disseminated tumor cells in peripheral blood.

Amplification of the MDM2 gene, but not expression of splice variants of MDM2 MRNA, is associated with prognosis in soft tissue sarcoma.

The MDM2 gene encodes a 90-kDa oncoprotein that is overexpressed in several human carcinomas, osteosarcomas, gliomas and soft tissue sarcomas (STSs). This overexpression is the result of several mechanisms, for example, enhanced transcription or translation, gene amplification and alternative splicing. We found that 19 of 67 (28.4%) STS specimens contained an amplified MDM2 gene. The amplification was more likely to be present in grade 1 tumors than in grade 2 or 3 tumors (58% of grade 1 tumors vs. 15% of grade 2 or 3 tumors, p = 0.001, chi(2) test). Furthermore, patients with tumors that contained an amplified MDM2 gene had a survival estimate (87 months) that was longer than that of patients with tumors that lacked an amplified gene (40 months; p = 0.02, log-rank test). Alternatively and aberrantly spliced MDM2 mRNAs were detected in human STSs by a highly sensitive reverse transcription-polymerase chain reaction method. Of 71 tumor samples, 38 (54%) showed evidence of the spliced forms, which included MDM2-A, MDM2-B and several variants exclusively expressed in STSs. A common feature of all forms was the absence of the MDM2 N-terminal region, which includes the TP53-binding region. Furthermore, the presence of the spliced forms was associated with elevated levels of TP53 (p = 0.01, chi(2) test). Although the presence of spliced forms was associated with late-stage tumor phenotypes (p = 0.05, chi(2) test), we observed no relationship between the presence of splice variants and patient outcome.

A MboII polymorphism in exon 11 of the human MDM2 gene occuring in normal blood donors and in soft tissue sarcoma patients: an indication for an increased cancer susceptibility?

The human MDM2 oncogene, well known as the tumor suppressor gene p53's partner, plays an important role in tumorigenesis whether it is dependent on or independent of TP53. In this study, we investigated in a PCR-sequencing analysis the exon 11 of the human MDM2 gene for gene alterations. A MboII polymorphism occurs in 8% of normal blood donors (8 out of 100 probands) and in 13% of the soft tissue sarcoma patients (11 out of 82 patients). Of note was that two STS patients carried the gene alteration only in the tumor specimens heterozygously but not in normal tissue. In a Kaplan-Meier analysis, patients without the polymorphism, indicated a median survival rate of 57 months, whereas, patients with the polymorphism survived on average only 38 months. We suggest that this polymorphism might be associated with an increased cancer susceptibility.