European Journal of Cancer

Editorial board

2010-03-01

EJC NEWS, Issue 5, 2010

2010-03-01

Staging early ovarian cancer: Impact on treatment decisions

Ralph S. Freedman — 2010-02-18

The search for clear evidence-based data supportive of treatment decisions in early stage ovarian cancer remains elusive. Previous trials have shown inconsistencies in surgical staging, most likely contributing to inclusion of patients with more extensive disease. In addition, tumours of low malignant potential have been included due to lack of pathology validation. Because of unanticipated delays in completing accrual, even the largest trials have had to be truncated combined or required meta-analysis to support stronger conclusions. Moreover lengthy trials could result in treatments being utilised that are different from standards of care at a trials conclusion. Nevertheless, a considerable amount of useful data have been assembled, collated and critically analysed in past reviews. The main focus here is on the paper by Petra Timmers et al. ‘Understanding the Problem of Inadequately Staging Early Ovarian Cancer,’ published in this issue. The database for this paper originated from ACTION 2003, and provides additional characterisation of the staging process utilised. Of the 40 participant sites, the lowest level of staging occurred at sites where fewer than 5 patients were entered. Sites entering more than 20 or even more than 10 patients had a higher frequency of optimum staging. But even at sites entering more than 20 patients complete staging was only achieved in approximately 36% of patients.

Amplification of epidermal growth factor receptor gene in renal cell carcinoma

2010-02-18

Abstract: Expression of epidermal growth factor receptor (EGFR) may be of prognostic value in renal cell cancer (RCC). Gene amplification of EGFR was investigated in a cohort of 315 patients with advanced RCC from a previously reported randomised study. Using fluorescent in situ hybridisation, only 2 patients (0.6%) had gene amplification; therefore gene amplification is of no prognostic value in RCC.

Future treatment of soft tissue sarcomas will be driven by histological subtype and molecular abberations

Jaap Verweij, Laurence H. Baker — 2010-02-08

Abstract: Soft tissue sarcomas, although sharing a mesenchymal origin, are a heterogeneous group of diseases. Nevertheless they are studied and frequently treated as if they were all the same. Recent developments suggest that a different approach may be more adequate. Genetic profiling studies have indicated that some soft tissue sarcoma subtypes, despite a distinct histo-pathological difference, may be closely related. Molecular biology research in addition has identified several subtype-specific oncogenes and their protein products that could serve as treatment targets. Since many of the new molecularly targeted agents do not induce tumour regression, but mainly result in growth inhibition, it is therefore necessary also to change the study end-point in screening studies in the search for active treatments. In view of all these it is proposed to consider using alternative end-points such as progression-free rates at pre-set times, or progression arrest at first evaluation. By using databases from large cooperative groups it should be possible to identify progression arrest rates for each specific subtype, and these could serve as reference for future trial design. Soft tissue sarcoma treatment and research will require a change of approach and necessitate global cooperation.

Predictive biomarkers for personalised anti-cancer drug use: Discovery to clinical implementation

Nayef A. Alymani, Murray D. Smith, David J. Williams, Russell D. Petty — 2010-02-08

Abstract: A priority translational research objective in cancer medicine is the discovery of novel therapeutic targets for solid tumours. Ideally, co-discovery of predictive biomarkers occurs in parallel to facilitate clinical development of agents and ultimately personalise clinical use. However, the identification of clinically useful predictive biomarkers for solid tumours has proven challenging with many initially promising biomarkers failing to translate into clinically useful applications. In particular, the ‘failure’ of a predictive biomarker has often only become apparent at a relatively late stage in investigation. Recently, the field has recognised the need to develop a robust clinical biomarker development methodology to facilitate the process. This review discusses the recent progress in this area focusing on the key stages in the biomarker development process: discovery, validation, qualification and implementation. Concentrating on predictive biomarkers for selecting systemic therapies for individual patients in the clinic, the advances and progress in each of these stages in biomarker development are outlined and the key remaining challenges are discussed. Specific examples are discussed to illustrate the challenges identified and how they have been addressed. Overall, we find that significant progress has been made towards a formalised biomarker developmental process. This holds considerable promise for facilitating the translation of predictive biomarkers from discovery to clinical implementation. Further enhancements could eventually be found through alignment with regulatory processes.

Understanding the problem of inadequately staging early ovarian cancer

P.J. Timmers, A.H. Zwinderman, C. Coens, I. Vergote, J.B. Trimbos — 2010-01-14

Abstract: Background: Early ovarian cancer patients are often incompletely staged during initial surgery. This omission can have serious adverse consequences for the prognosis of patients as the completeness of surgical staging has been identified as an independent prognostic parameter for survival. The reasons for the problem of inadequate staging of early ovarian cancer are largely unknown. We have analysed the data of a large randomised trial in early ovarian cancer in which detailed information of the surgical staging procedure was monitored.Methods: Data of the EORTC Adjuvant ChemoTherapy In Ovarian Neoplasm (ACTION) Trial were used in which 448 early ovarian cancer patients were randomised between postoperative chemotherapy in one arm and observation following surgery in the other. In this trial strict criteria for surgical staging were advised but optimal, complete staging was performed in only 1/3 of patients. Staging characteristics of the incompletely staged patients were analysed and factors that could explain the failure to perform a complete staging were studied.Results: Sampling of para-aortic nodes was omitted in 78% of the incompletely staged patients, while 52% of these patients had no pelvic lymph node dissection. Taking blind biopsies from different peritoneal sites was not performed in more than 1/3 of the incompletely staged group. Omission of the staging steps ranged from 3% (infracolic omentectomy) to 55% (biopsy of the right hemi-diaphragm). A significant difference (p=0.04) between the fraction of completely staged patients was found when comparing institutes who entered less than 5 patients (21%) versus those who included more than 20 patients (37%) in the trial.Conclusions: Even in a randomised trial in which comprehensive surgical staging was strongly advised in the study protocol the majority of patients (66%) were incompletely staged. Factors relating to a lack of surgical skills attributed most to the number of incompletely staged patients, but insufficient knowledge of the tumour behaviour and routes of spread of ovarian cancer also contributed substantially to this problem. Multicentre trials recruiting patients from many institutes with small volume contribution to the study, run the risk of inadequate adherence to the study protocol.

A randomised phase II study of combination chemotherapy with epirubicin, cisplatin and capecitabine (ECX) or cisplatin and capecitabine (CX) in advanced gastric cancer

2010-01-08

Abstract: Background: Both cisplatin/capecitabine (CX) and epirubicin plus CX (ECX) have clearly demonstrated efficacy against advanced gastric cancer (AGC).Methods: Chemotherapy-naïve patients with histologically confirmed, measurable AGC were randomised to receive CX (cisplatin 75mg/m2 iv on day 1 and capecitabine 1000mg/m2 bid po on days 1–14) or ECX (epirubicin 50mg/m2 plus CX) every 3weeks. The primary endpoint was progression-free survival (PFS).Results: Of the 91 registered patients, 45 patients were treated with CX and 44 with ECX. A total of 241 CX (median, 6; range, 1–12) and 201 ECX (median, 5; range, 1–11) cycles were delivered. Treatment duration was similar for both arms (4.4 for CX versus 4.2months for ECX). There was no relevant difference in the occurrence of overall grade 3 or 4 toxicities between the CX and ECX arms (80% versus 78%, respectively; P=0.516). However, none in the CX and 12% in the ECX arm discontinued treatment because of toxicity. There were no significant differences in therapeutic efficacy between CX and ECX with respect to the response rate (38% versus 37%, respectively) and PFS (6.4 versus 6.5months).Conclusion: Both CX and ECX appear to be active as first-line chemotherapy for AGC, and the safety profiles are acceptable. Given the comparable efficacy results, CX could be a reasonable standard chemotherapy for untreated AGC patients.

17ß-Hydroxysteroid dehydrogenase type 1 as predictor of tamoxifen response in premenopausal breast cancer

2010-01-11

Abstract: 17ß-Hydroxysteroid dehydrogenases (17HSDs) are involved in the local regulation of sex steroids. 17HSD1 converts oestrone (E1) to the more potent oestradiol (E2) and 17HSD2 catalyses the reverse reaction. The aim of this study was to investigate the expression of these enzymes in premenopausal breast cancers and to analyse if they have any prognostic or tamoxifen predictive value. Premenopausal patients with invasive breast cancer, stage II (UICC), were randomised to either 2years of adjuvant tamoxifen (n=276) or no tamoxifen (n=288). The median follow-up was 13.9years (range 10.5–17.5). The expression of 17HSD1 and 17HSD2 was analysed with immunohistochemistry using tissue microarrays. The enzyme expression level (–/+/++/+++) was successfully determined in 396 and 373 tumours, respectively. Women with hormone-receptor positive tumours, with low levels (–/+/++) of 17HSD1, had a 43% reduced risk of recurrence, when treated with tamoxifen (Hazard Ratio (HR)=0.57; 95% confidence interval (CI), 0.37–0.86; p=0.0086). On the other hand high expression (+++) of 17HSD1 was associated with no significant difference between the two treatment arms (HR=0.91; 95% CI, 0.43–1.95; p=0.82). The interaction between 17HSD1 and tamoxifen was significant during the first 5 years of follow-up (p=0.023). In the cohort of systemically untreated patients no prognostic importance was observed for 17HSD1. We found no predictive or prognostic value for 17HSD2. This is the first report of 17HSD1 in a cohort of premenopausal women with breast cancer randomised to tamoxifen. Our data suggest that 17HSD1 might be a predictive factor in this group of patients.

Phase I evaluation of cediranib, a selective VEGFR signalling inhibitor, in combination with gefitinib in patients with advanced tumours

2010-01-11

Abstract: Aim: Cediranib is a highly potent inhibitor of vascular endothelial growth factor receptor (VEGFR) signalling. Preclinical and clinical data suggest that inhibition of the VEGFR and epidermal growth factor receptor (EGFR) pathways may be synergistic. Combination treatment with cediranib and gefitinib, an EGFR signalling inhibitor, was evaluated in patients with advanced solid tumours.Patients and methods: Ninety patients received treatment in this four-part, open-label study (NCT00502060). The patients received once-daily oral doses of cediranib (20–45mg) and gefitinib 250mg (part A1; n=16) or 500mg (part B1; n=44). A cohort expansion phase investigated the potential pharmacokinetic interaction of cediranib 30mg with gefitinib 250mg (part A2; n=15) or 500mg (part B2; n=15). The primary objective was to assess the safety and tolerability of cediranib with gefitinib. Secondary assessments included pharmacokinetics, efficacy and pharmacodynamics.Results: Combination treatment was generally well tolerated; the protocol-defined maximum-tolerated dose of cediranib was 30mg/day with gefitinib 250mg/day (part A1) and cediranib 45mg/day was the maximum dose investigated with gefitinib 500mg/day (part B1). The most common adverse events were diarrhoea (84 [93%]), anorexia (63 [70%]) and fatigue (60 [67%]). Cediranib pharmacokinetic parameters were not substantially different when given alone or in combination with gefitinib. Gefitinib pharmacokinetic parameters were similar to those seen previously with gefitinib monotherapy. Efficacy results included eight (9%) confirmed partial responses (6 renal; 1 lung; 1 osteosarcoma) and 38 (42%) patients with stable disease. Pharmacodynamic assessments demonstrated changes in levels of VEGF and soluble VEGFR-2 following treatment.Conclusions: Combination treatment was generally well tolerated and showed encouraging antitumour activity in patients with advanced solid tumours. These results merit further exploration.

Understanding the impact of public policy on cancer research: A bibliometric approach

Grant Lewison, Arnie Purushotham, Malcolm Mason, Gordon McVie, Richard Sullivan — 2010-01-11

Abstract: With global spend on cancer research from the public sector now in excess of 14 billion euro, as well as the increasing burden of disease in market economies and low-middle income countries through changing demographics (ageing and population growth) cancer is now one of the most complex and global public policy issues. Using novel bibliometrics we have sought to investigate changes in research activity (total output), relative commitment and collaborations between countries/regions with similar healthcare and population and development parameters – United Kingdom, France, Germany, Canada and Sweden – to assess the utility of this policy research approach by analysing two different cohorts (1995–1999 and 2000–2004) to study the impact of changes on research publications as a surrogate for overall research activity.

First-time-in-man and pharmacokinetic study of weekly oral perifosine in patients with solid tumours

2010-01-15

Abstract: Aim: To identify the maximum-tolerated dose (MTD) and pharmacokinetics of oral perifosine.Methods: Patients with solid tumours received perifosine at dosages ranging from 100–800mg/week. Eligibility criteria included life expectancy>12weeks, WHO performance status⩽2, normal blood, liver and renal functions and no recent anticancer treatment. Drug concentrations were analysed by HPLC–MS/MS.Results: Thirty six patients were recruited (75% males, mean age 54.7years, performance status 1 in 72.2%). Adverse events included nausea (69.4%), diarrhoea (55.6%), vomiting (52.8%) and abdominal pain (13.9%). Antiemetic regimens including glucocorticoids, dopamine antagonists and 5-HT3-antagonists were used as treatment and/or prophylaxis in 50% of the patients. Though MTD was formally not reached with 800mg/week, the treatment discontinuation due to diarrhoea and vomiting likely related to perifosine in two cases led to the decision to stop further dose escalation. Pharmacokinetics after a single dose were median tmax=8.0–24.2h, median t1/2=81.0–115.9h and meangeo CL/f=0.28–0.43mL/min/kg. Urinary excretion was below 1%. Perifosine slightly accumulated and steady state was nearly reached after 2–3weeks.Conclusion: Oral perifosine was tolerable up to 600mg/week in cancer patients when administered with meal and prophylactic antiemetics. Based on its half-life of about 4days, a weekly regimen may be appropriate.

Liver and gallbladder cancer in immigrants to Sweden

Kari Hemminki, Seyed Mohsen Mousavi, Andreas Brandt, Jianguang Ji, Jan Sundquist — 2010-01-11

Abstract: Background: The changes of cancer incidence upon immigration can be used as an estimator of environmental influence on cancer risk. We studied site-specific liver and biliary cancers in first-generation immigrants to Sweden with an aim to search for aetiological clues and to find evidence for indigenous incidence rates.Material and methods: We used the nation-wide Swedish Family-Cancer Database to calculate standardised incidence ratios (SIRs) in immigrants compared to native Swedes.Results: A total of 1428 cancers were identified in immigrants whose median ages (years) at immigration were 27 for men and 26 for women and whose median diagnostic ages were 64 and 66, respectively. The highest SIRs of 6.7 for primary liver cancer were observed for men from East Asia and sub-Saharan Africa. Increased SIRs were recorded for male immigrants from previous Yugoslavia (1.78), Southern Europe (2.91), Turkey (2.15) and Asian Arab countries (2.89). For gallbladder cancer, only women from the Indian subcontinent (3.84) and Chile (2.34) had increased risk while some Northern European immigrants showed decreased risks.Conclusions: Primary liver cancer was increased in immigrants from endemic regions of hepatitis B virus infection but also from large regions lacking cancer incidence data, North Africa, Asian Arab countries, Turkey and previous Yugoslavia; these are probably intermediary risk regions for this infection. The consideration of these regions as risk areas would justify active diagnostic and vaccination programs. The increase in gallbladder cancer in Chileans and Indians suggests that some persistent damage was inflicted before emigration, characterisation of which will be a challenge for aetiological studies.

Plasma 25-hydroxyvitamin D and prostate cancer risk: The Multiethnic Cohort

2010-01-11

Abstract: The purpose of this study was to examine the relationship of plasma 25-hydroxyvitamin D (25(OH)D) concentrations to prostate cancer within a large multiethnic cohort in Hawaii and California using a nested case-control design. The study included 329 incidents of prostate cancer of African American, Native Hawaiian, Japanese, Latino and White ancestry, and 656 controls matched on age, race/ethnicity, date/time of blood collection and fasting status. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CI). No association with prostate cancer risk was found in an analysis based on quartiles of 25(OH)D. When clinically defined cutpoints were used, there was no increased risk for the lowest 25(OH)D concentration (OR for <20 versus 30–<50ng/ml=1.10, 95% CI=0.68–1.78), while there was a suggestive increased risk for higher concentrations (OR for ⩾50ng/ml=1.52, 95% CI=0.92–2.51). The findings from this prospective study of men in the Multiethnic Cohort do not support the hypothesis that vitamin D lowers the risk of prostate cancer. Further follow-up is warranted to determine whether the findings are consistent across ethnic groups.

Reduced risk of oestrogen receptor positive breast cancer among peri- and post-menopausal women in Scotland following a striking decrease in use of hormone replacement therapy

2010-02-01

Abstract: Many countries report a decline in breast cancer incidence among peri- and post-menopausal women following a decline in HRT prescribing. To investigate recent Scottish incidence trends, European age-standardised incidence rates from 1997 to 2005 were stratified by method of first detection, ER status and age group. We developed change point models of the annual age-specific cases for the peri- and post-menopausal age groups and ER status using Poisson regression.In Scotland all HRT categories together show a 32.4% increase in the number of items dispensed in 1993–2000 followed by a striking 61.8% decline by 2007.The incidence rates of screen-detected tumours increased gradually in the 50–64 and 65–74 age groups. For the older age group this increase accelerated after 2003 corresponding to an extension of the age range of screening.For ER positive tumours in the 50–64 age group, age-standardised rates increased 31.5% from 1997 to 2000, followed by a statistically significant decrease of 11.2% by 2005 (change in slope=−0.0943, P<0.0001). We conclude that an overall incidence in the 50–64 age group declined since 2000 reflecting the sudden fall in HRT dispensed items and is largely accounted for by the decrease in ER positive tumour incidence. A longer term decline in ER negative tumours for this age group was pre-existing and is unaffected by the collapse in HRT prescribing.

Trop-2 overexpression as an independent marker for poor overall survival in ovarian carcinoma patients

2010-01-11

Abstract: Background: Prognostic factors currently available are insufficient to predict the clinical course of epithelial ovarian cancer (EOC). In a previous microarray study we identified the human trophoblast cell surface antigen Trop-2 as one of the top differentially expressed genes in serous papillary EOCs compared to normal human ovarian surface epithelial (HOSE) short-term cultures. The aim of the present investigation was to analyse Trop-2 expression at mRNA and protein level and to assess its prognostic significance in EOC.Methods: Using quantitative real-time PCR we tested a total of 104 fresh-frozen EOC tissues and 24 HOSE for Trop-2 mRNA expression. Trop-2 protein expression was then examined by immunohistochemistry in matched formalin-fixed paraffin-embedded EOC samples and in 13 normal ovaries. Finally, we correlated Trop-2 expression to EOC conventional clinicopathological features and patient outcomes.Results: We found a significant Trop-2 mRNA and protein upregulation in EOCs compared to normal controls (p<0.001). Trop-2 protein overexpression was significantly associated with the presence of ascites (p=0.04) and lymph node metastases (p=0.04). By univariate survival analysis, Trop-2 protein overexpression was significantly associated with decreased progression-free (p=0.02) and overall survival (p=0.01). Importantly, Trop-2 protein overexpression was an independent prognostic marker for shortened survival time in multivariate Cox regression analysis (p=0.04, HR=2.35, CI95%=1.03–5.34).Conclusions: Our results indicate, for the first time, that Trop-2 protein overexpression correlates with an aggressive malignant phenotype and may constitute a novel prognostic factor for EOC. The targeting of Trop-2 overexpression by immunotherapeutic strategies may represent an attractive and potentially effective approach in patients harbouring EOC.

Y-box binding protein-1 (YB-1) promotes cell cycle progression through CDC6-dependent pathway in human cancer cells

2010-01-15

Abstract: Y-box binding protein-1 (YB-1) plays pivotal roles in acquisition of global drug resistance and cell growth promotion through transcriptional activation of genes for both drug resistance and growth factor receptors. In this study, we investigated whether YB-1 is involved in regulation of the cell cycle and cell proliferation of human cancer cells. Treatment with YB-1 siRNA caused a marked suppression of cell proliferation and expression of a cell cycle related gene, CDC6 by cancer cells. Of cell cycle of cancer cells, S phase content was specifically reduced by knockdown of YB-1. The overexpression of CDC6 abrogated this inhibition of both cell proliferation and S phase entry. ChIP assay demonstrated that YB-1 binds to a Y-box located in the promoter region of the CDC6 gene. Expression of cyclin D1, CDK1 and CDK2 was also reduced with increased expression of p21Cip1 and p16INK4A when treated with YB-1 siRNA. Furthermore, the nuclear YB-1 expression was significantly associated with the level of CDC6 nuclear expression in patients with breast cancer. In conclusion, YB-1 plays an important role in cell cycle progression at G1/S of human cancer cells. YB-1 thus could be a potent biomarker for tumour growth and cell cycle in its close association with CDC6.

Recombinant kringle 5 from plasminogen antagonises hepatocyte growth factor-mediated signalling

2010-01-11

Abstract: The blood protein plasminogen is proteolytically cleaved to produce angiostatin and kringle 5 (K5), both of which are known angiogenesis inhibitors. A common structural element between K5, angiostatin and other endogenous angiogenesis inhibitors is the presence of the kringle protein-interacting domain. Another kringle domain-containing protein, hepatocyte growth factor (HGF), promotes angiogenesis by binding to and stimulating the tyrosine kinase receptor Met. HGF binding to Met is dependent on the kringle domains of HGF. Because both K5 and HGF contain kringle motifs and because these proteins have opposite effects on angiogenesis, we hypothesised that K5 can antagonise HGF-mediated signalling in a Met-dependent manner. We determined that K5 binding to H1299 cells is competed by HGF suggesting that these two proteins bind to the same protein. Purified K5 immunoprecipitates with Met and this interaction is abolished by increasing doses of HGF. Using proliferation, phosphorylation of Met and Akt as markers of HGF activity, we determined that K5 inhibits HGF-mediated signalling. Taken together, these data support a model by which K5 binds to Met and functions as a competitive antagonist of HGF signalling and presents a novel mechanism of action of K5.

VEGF-A promotes lymphoma tumour growth by activation of STAT proteins and inhibition of p27KIP1 via paracrine mechanisms

2010-01-11

Abstract: Increased levels of circulating VEGF-A have been demonstrated in patients with non-Hodgkin lymphoma (NHL) and are associated with progressive disease and poor clinical outcome. We investigated the role of VEGF-A in lymphoma tumour growth on a molecular level in order to identify the mechanism of VEGF-A-promoted tumour growth and to identify the potential targets for therapy. We used a model in which Daudi (human Burkitt lymphoma) tumour cells were transduced with VEGF-A165 or an empty vector (negative control) and subcutaneously injected in NOD/SCID mice. The weight of tumours overexpressing VEGF-A was increased 4-fold compared to that of control tumours (p<0.0001), whereas no in vitro growth advantage was demonstrated upon VEGF-A overexpression. VEGF-A-tumours were associated with increased microvessel densities (p=0.004) and increased tumour cell proliferation (Ki67; p<0.001) compared to control tumours. VEGF-A-tumours were characterised by upregulation of phosphorylated STAT-4 and STAT-6 and downregulation of phospho-p27KIP1, a crucial cell cycle inhibitor (p<0.05). This was accompanied by increased levels of phosphorylated receptor tyrosine kinases, including EGFR (ErbB-2 and ErbB-4, p<0.05), an upstream regulator of STAT proteins. We demonstrated that various mouse-derived cytokines produced by mouse-derived tumour stromal cells are upregulated in VEGF-A-tumours compared to control tumours (p<0.05). These results indicate an important role for the tumour microenvironment in paracrine promotion of lymphoma tumour growth in response to tumour-derived VEGF-A. In conclusion, lymphoma-derived VEGF-A promoted lymphoma tumour growth in a paracrine loop by activation of tumour stromal cells. Our study reveals VEGF-A and STAT proteins as potential additional targets in the treatment of lymphoma.

Red wine polyphenols cause growth inhibition and apoptosis in acute lymphoblastic leukaemia cells by inducing a redox-sensitive up-regulation of p73 and down-regulation of UHRF1

2010-01-14

Abstract: Several epidemiological studies suggest that a diet rich in fruits and vegetables, which contain high levels of polyphenols, is associated with a reduced risk of cancer. The aim of the present study was to determine whether a red wine polyphenolic extract (RWPs, a rich source of polyphenols; 2.9g/L) affects the proliferation of human lymphoblastic leukaemia cells (Jurkat cells) and, if so, to determine the underlying mechanism. Cell proliferation and viability were determined by the MTS and trypan blue exclusion assays, respectively. Cell cycle analysis, apoptosis activity and oxidative stress levels were assessed by flow cytometry, and the expression of p73, UHRF1 and active caspase-3 by Western blot analysis. RWPs inhibited the proliferation of Jurkat cells and induced G0/G1 cell cycle arrest in a concentration-dependent manner. Moreover, RWPs triggered apoptosis, which is associated with an increased expression level of the pro-apoptotic protein p73 and the active caspase-3. RWPs induced apoptosis confirmed by DNA fragmentation analysis, and this effect was associated with down-regulation of the antiapoptotic protein UHRF1. Furthermore RWPs significantly increased the formation of reactive oxygen species (ROS). Intracellular scavengers of superoxide anions (MnTMPyP, MnTBAP, PEG-SOD) prevented the RWPs-induced formation of ROS and apoptosis, while native extracellular superoxide dismutase (SOD) was without effect. In addition, the effect of RWPs on the expression levels of p73, active caspase-3 and UHRF1 was also prevented by MnTMPyP. Thus, these findings indicate that RWPs induce apoptosis in Jurkat cells by a redox-sensitive mechanism involving the intracellular formation of superoxide anions and consequently the up-regulation of p73 and down-regulation of UHRF1.

Hypoxia upregulates adhesion ability to peritoneum through a transforming growth factor-β-dependent mechanism in diffuse-type gastric cancer cells

Satoru Noda, Masakazu Yashiro, Takafumi Nshii, Kosei Hirakawa — 2010-02-10

Abstract: Gastric cancer cells leaving the primary tumour are exposed to low oxygen levels in the peritoneal cavity; however, peritoneal metastatic phenotypes of hypoxic cancer cells remain unclear. We used 6 gastric cancer cell lines, including 3 diffuse-type gastric cancer (DGC) and 3 non-DGC cell lines. Using adhesion assay, we examined the effect of hypoxic conditions on their ability to adhere to peritoneal components. The expression level of transforming growth factor-β (TGF-β) and integrins mRNA of cancer cells was examined using reverse transcriptase-polymerase chain reaction. We further examined the effect of anti-integrin neutralising antibodies and a TGF-β receptor inhibitor on the adhesion ability of hypoxic cancer cells. The binding ability of DGC cells was higher than that of non-DGC cells; it was significantly increased by hypoxic (1% O2) conditions compared to normoxic (21% O2) conditions. In contrast, no remarkable change in adhesion ability was observed in the non-DGC cells under normoxic and hypoxic conditions. Integrins and TGF-β expression of hypoxic DGC cells was significantly higher than that of normoxic cells. TGF-β increased the adhesion ability and α2-, α3- and α5-integrin expression of hypoxic DGC cells, whereas the TGF-β receptor inhibitor decreased them. Neutralising antibodies against α2-, α3- and α5-integrin inhibited the adhesion ability of DGC cells. These findings suggested that hypoxic conditions promote the adhesion of DGC cells to the peritoneum. The upregulation of α2-, α3- and α5-integrin by TGF-β under hypoxic conditions may be one of the mechanisms responsible for the high metastatic potential of hypoxic DGC cells to the peritoneum.

Calendar

2010-03-01