Biomedical subjects

Steffen Hauptmann

Publications and source records attributed to Steffen Hauptmann.

At least 19 recordsLinked to original sources

PubMed2006

Genetic dissection of apoptosis and cell cycle control in response of colorectal cancer treated with preoperative radiochemotherapy.

BACKGROUND: In previous analyses we identified therapy-induced upregulation of the CDK inhibitor p21CIP/WAF-1 and consequently decreased tumor cell proliferation or loss of Bax as adverse factors for survival in rectal cancer treated with radiochemotherapy. Here, we address the individual role of p53 and its transcriptional targets, p21CIP/WAF-1 and Bax, on apoptosis induced by individual components of multimodal anticancer therapy, i.e. 5-fluorouracil (5-FU), ionising gamma-radiation (IR) and heat shock/hyperthermia. METHODS: We analysed tumor samples 66 patients with rectal carcinoma treated by a neoadjuvant approach with radiochemotherapy +/- heat shock/hyperthermia for the expression and mutation of p53 and the expression of p21CIP/WAF-1 and Bax. These data were correlated with the tumor response. The functional relevance of p53, p21CIP/WAF-1 and Bax was investigated in isogeneic HCT116 cell mutants treated with 5-FU, IR and heat shock. RESULTS: Rectal carcinoma patients who received an optimal heat shock treatment showed a response that correlated well with Bax expression (p = 0.018). Local tumor response in the whole cohort was linked to expression of p21CIP/WAF-1 (p < 0.05), but not p53 expression or mutation. This dichotomy of p53 pathway components regulating response to therapy was confirmed in vitro. In isogeneic HCT116 cell mutants, loss of Bax but not p53 or p21CIP/WAF-1 resulted in resistance against heat shock. In contrast, loss of p21CIP/WAF-1 or, to a lesser extent, p53 sensitized predominantly for 5-FU and IR. CONCLUSION: These data establish a different impact of p53 pathway components on treatment responses. While chemotherapy and IR depend primarily on cell cycle control and p21, heat shock depends primarily on Bax. In contrast, p53 status poorly correlates with response. These analyses therefore provide a rational approach for dissecting the mode of action of single treatment modalities that may be employed to circumvent clinically relevant resistance mechanisms in rectal cancer.

Antimetabolites, Antineoplastic↗

PubMed2006

Ezrin expression is related to poor prognosis in FIGO stage I endometrioid carcinomas.

As a cortical cytoskeletal protein, ezrin adapts the cytoplasmic tail of CD44 to the actin-based cytoskeleton and is functionally involved in migration and adhesion that are prerequisites for metastasis. To assess the importance of ezrin and its associated protein osteopontin for the progression of endometrioid carcinoma in FIGO stage I, we analyzed paraffin-embedded tissue from 164 patients by immunohistochemistry and correlated these data with clinicopathological parameters. Ezrin was expressed in normal proliferating endometrial glands, as was confirmed by quantitative PCR and immunohistochemistry. In endometrioid carcinoma, enhanced ezrin expression correlated with a reduced overall survival in univariate analysis (P = 0.041). In contrast, no significant correlation was found for osteopontin. In multivariate survival analysis, among FIGO grade 3 and age, ezrin was still found to be an independent risk factor (relative risk 2.2, confidence interval 1.0-5.4, P = 0.047). Hence, elevated ezrin expression is a new independent prognostic marker in FIGO stage I endometrioid carcinoma, and thus provides further evidence for an important role of ezrin in tumor progression.

Aged↗

PubMed2006

Ezrin promotes ovarian carcinoma cell invasion and its retained expression predicts poor prognosis in ovarian carcinoma.

The majority of patients diagnosed with ovarian carcinoma are classified as being in advanced stage of disease. In a situation of cancer spread throughout the abdominal cavity, a successful curative treatment is difficult to achieve. Therefore, preventing binding of tumor cells to the mesothelium is crucial for patients' outcome. One important mechanism is the interaction between hyaluronic acid and the CD44 receptor with its submembrane linking complex. This consists of ezrin, radixin, and moesin and connects the CD44 receptor with the cytoskeleton. To assess the role of ezrin and moesinfor ovarian carcinoma progression, we analyzed ovarian carcinoma samples from 105 patients for expression of ezrin and moesin by immunohistochemistry and correlated these data with several clinicopathological parameters. To elucidate the functional importance of ezrin and moesin, their expression was inhibited in SKOV-3 cells by RNA interference. Ezrin and moesin were strongly expressed in 49 and 48% of ovarian carcinoma samples, respectively, and their presence correlated with reduced overall survival in univariate analysis (ezrin, p=0.0189; moesin, p=0.0351). In multivariate analysis (including FIGO stage, residual tumor, histological type, and Silverberg grading), ezrin still remained significant as an independent risk factor (relative risk, 2.39; p=0.012). In SKOV-3 cells, siRNA against ezrin but not moesin inhibited in vitro invasion. These data imply that ezrin is necessary for tumor cell invasion, and the better prognosis of ovarian carcinomas lacking ezrin is probably related to their impaired invasion.

Cell Line, Tumor↗

PubMed2006

Disparities between male and female patients with thyroid cancers: sex difference or gender divide?

OBJECTIVE: This investigation was undertaken to quantify histopathological disparities between male and female patients with sporadic and hereditary thyroid cancers, which may reflect a biological 'sex difference' or a behavioural 'gender divide'. DESIGN: Retrospective cohort analysis (November 1994-January 2006). PATIENTS: 1298 Consecutive surgical patients with sporadic papillary (n = 587), sporadic follicular (n = 232), sporadic medullary (n = 320), and hereditary medullary thyroid cancers (n = 159) from a tertiary referral centre. MEASUREMENTS: Age at diagnosis of cancer, primary tumour diameter, frequency of extrathyroidal extension, lymph node and distant metastases, and cancer subtypes. RESULTS: Primary diameters of sporadic tumour entities (papillary, 26.0 vs. 19.3 mm; follicular, 54.9 vs. 35.1 mm; and medullary, 27.9 vs. 20.8 mm), but not hereditary medullary cancers, were significantly (P <or= 0.001) larger in male patients. Likewise, lymph node metastases from sporadic papillary cancers (60%vs. 44%, P < 0.001), the insular subtype in sporadic follicular cancers (22%vs. 8%, P = 0.003), extrathyroidal extension of sporadic medullary cancers (35%vs. 15%, P < 0.001), and distant metastases from sporadic medullary cancers at the most recent operation (29%vs. 15%, P = 0.002) were seen significantly more often with male patients. No significant differences were observed between male and female patients with hereditary medullary cancers, half of which were detected by screening. CONCLUSIONS: Our data emphasize the need for earlier diagnosis and intervention in male patients to ensure that male sex will cease sometime to constitute an ominous prognostic marker of advanced thyroid cancer.

Adenocarcinoma, Papillary↗

PubMed2005

Significance of HDMX-S (or MDM4) mRNA splice variant overexpression and HDMX gene amplification on primary soft tissue sarcoma prognosis.

The product of the HDMX (or MDM4) gene is structurally related to the MDM2 oncoprotein and is also capable of interacting with the tumor suppressor protein p53. The aim of our study was to determine the amplification status of the HDMX gene and the expression of the HDMX mRNA (particularly that of the HDMX-S splice variant) in soft-tissue sarcomas (STS). Patients with STS were evaluated for the status of HDMX gene amplification (n = 66) and HDMX-S mRNA expression (n = 57) within their tumors. DNA, total RNA and protein were isolated from frozen tumor tissue. We determined that the HDMX-S splice variant transcript was predominant in a subset (14%) of tumor samples and that its expression was correlated with decreased patient survival (15 vs. 53 months, p < 0.0001, log-rank test) and with a 17-fold increased risk of a tumor-related death (p < 0.0001, multivariate Cox's regression model). The tumors from these patients also expressed elevated levels of HDMX-S protein. The HDMX gene was amplified in 17% of STSs, and the gene amplification was associated with poor prognosis (RR = 6.5, p < 0.0001). There was no correlation between the HDMX gene amplification and overexpression of the HDMX-S splice variant. In summary, our data indicate that both the overexpression of the HDMX-S transcript as well as HDMX gene amplification are important prognostic markers for STS.

Adult↗

PubMed2005

Transposable elements--is there a link between evolution and cancer?

Currently, the most predominant theory concerning the formation of cancer is that it is a genetic accident. Accordingly, various agents are thought to cause DNA damage which then subsequently activates oncogenes and inactivates tumor suppressor genes. This article, however, describes a theory that interprets cancer as a misguided adaptation. Stressors, which cannot be compensated for with the usual cell possibilities might arouse evolutionary mechanisms intended to create new protein variants. One of these is the activation of transposable elements which leads to a reformatting of the genome. The result of this process is either a cell that survives very well under stress (and will, therefore, never be detected), a dead cell (in case the process is ineffective), or a more or less abnormal and harmful cell that builds up a new but cancerous organ. This theory explains the complex genetic alterations which are present in almost all cancer cells. It also explains the action of non-mutagenic carcinogens. As part of the reformatting process of the cancer cell genome, activation of oncogenes and inactivation of tumor suppressor genes are not stochastic events but the result of an unlucky genomic composition.

Carcinogens↗

PubMed2005

Elevated expression of survivin-splice variants predicts a poor outcome for soft-tissue sarcomas patients.

The aim of this study was to investigate the level and the prognostic value of the expression of different survivin transcript variants--survivin, survivin-DeltaEx3 and survivin-2B--in tumours of 76 soft tissue sarcoma (STS) patients. The expression of survivin transcript variants in STS tissue samples and in 12 nonmalignant control tissues was analysed by quantitative RT-PCRs. Expression levels of all survivin transcript variants were strongly elevated in STS compared to normal tissues. A positive correlation between expression of splice variants and tumour stage was found (P=0.02; chi2 test). The multivariate Cox's proportional hazards regression model revealed a 7.3-fold increased risk of tumour-related death for patients with survivin-DeltaEx3 overexpressing tumours (P=0.007). The effect of surivivin (wildtype variant) and survivin-2B was less pronounced but still significant (2.2- and 1.9-fold, resp., P<0.05 each). Our results show for the first time that mRNA expression of survivin-variants is significantly correlated to a poor prognosis for STS patients, and we suggest expression of survivin splice variants together with tumour stage as independent predictor of survival.

Biomarkers, Tumor↗

PubMed2005

Influence of various cytokines on adhesion and migration of the colorectal adenocarcinoma cell line HRT-18.

The stroma of colorectal adenocarcinoma contains both abundant extracellular matrix (ECM) and an inflammatory cell infiltrate. The latter is the source of various cytokines, present in different concentrations in the tumor cell microenvironment. The aim of the present study was to investigate whether cytokines act as motility factors for HRT-18 rectal carcinoma cells and if this effect depends on the ECM. The main result of our study is that cytokines affect tumor cell motility in a matrix-dependent manner, and that stimulatory and inhibitory effects may depend on the composition of the ECM. Hepatocyte growth factor/scatter factor was the strongest migration factor for HRT-18 cells independent of the ECM. On the other hand, IL-6 was a strong migration stimulator for cells on Tenascin-C but was inhibitory on collagen type V. Therefore, different degrees of invasiveness at the tumor-host interface are not necessarily related to specific genetic alterations but might be related to different environmental conditions as well.

Adenocarcinoma↗

PubMed2005

Activation of mitogen-activated protein kinase is required for migration and invasion of placental site trophoblastic tumor.

Placental site trophoblastic tumor (PSTT) is a gestational neoplasm derived from the extravillous (intermediate) trophoblast of the implantation site. PSTT is characterized by a highly invasive phenotype, but the molecular mechanisms are poorly understood. In this report, we demonstrate that PSTTs expressed the activated (phosphorylated) form of mitogen-activated protein kinase (MAPK) in 84% of cases, whereas the normal extravillous trophoblastic cells did not. To characterize the role of MAPK activation in PSTT, we established the first PSTT cell culture, IST-2, from a surgically resected PSTT. IST-2 cells expressed HLA-G and Mel-CAM but not E-cadherin, an immunophenotype characteristic of PSTT. IST-2 cells were highly motile and invasive in culture as compared to choriocarcinoma JEG-3 cells and normal extravillous trophoblastic cells. Based on wound assay, time-lapse videomicroscopy for cell tracking, and invasion chamber assays, we found that the motility and invasion of IST-2 cells were significantly reduced (P<0.01) after treatment with the MEK inhibitors CI-1040 and PD 59089, which prevent activation of MAPK. In contrast, neither compound had any effect on normal extravillous trophoblastic cells or JEG-3 cells. In conclusion, our findings demonstrate a functional role of MAPK activation in the motility and invasion of PSTT.

Benzamides↗

PubMed2005

[Necrotizing fasciitis of the head and neck].

Necrotizing fasciitis (NF) is a potentially lethal soft tissue infection characterized by cutaneous necrosis, suppurative fasciitis, vascular thrombosis and extreme systemic toxicity. It is a rare entity in the head and neck region, but occur most frequently in patients with diabetes and chronic alcoholism. Mostly involved are immunodeficient patients with banal infections of the upper aerodigestive tract, small traumas, but also after surgical procedures. Necrotizing fasciitis is an infection caused by aerobic or anaerobic microorganisms. A strong complication is a streptococcus-associated-toxic shock-syndrome which should be prevented because it is often associated with letal outcome. Septicemia and systemic toxic effects may lead to death within as short a time as 2 to 4 days. Necrotizing fasciitis is often misdiagnosed or the diagnosis is delayed with a mortality rate of approximately 30-70%. Once identified, treatment consists of antimicrobial therapy and surgical debridement followed at a later date with reconstructive surgery. We present a fatal case of craniofacial necrotizing fasciitis (NF) in a 63-year-old diabetic and chronic alcoholic man and discuss it's pathophysiology, clinical manifestations and the best therapeutic choice for this disease. A review of the literature with the clinical presentations, bacteriology diagnosis and treatment was presented.

Candida albicans↗

PubMed2005

[Multifocal adult rhabdomyoma of the neck: a rare entity].

Extracardiac rhabdomyoma comprise 2% of all tumors of skeletal muscle differentiation. Seventy percent of extracardiac rhabdomyoma occur in the head and neck region and have been subclassified into adult and fetal types. There are only about 100 cases reported in the literature. A review of the world literature revealed about 19 acceptable cases of benign, multifocal adult-type rhabdomyoma with a distinct male predominance. The pathogenesis of this benign striated muscle tumor is still unclear. These slow-growing tumors remain asymptomatic for a long period. The diagnosis of head and neck rhabdomyoma is based on histology and immunhistochemical studies. The differential diagnoses of rhabdomyoma in adults are myoblastoma or Abrikossof tumor, reticulohistiocytoma, rhabdomyosarcoma and hibernoma. We present a case of multifocal rhabdomyomas in the paratracheal and parapharyngeal space and discuss the clinicopathological features of this lesion. Although adult rhabdomyomas have a distinct histology, they often are mistaken for a variety of other lesions, particularly Abrikossof tumor. Light microscopy showed large round to elongated cells with granular, highly eosinophilic cytoplasm, often with peripheral vacuolation. Histology showed typical patterns of an adult type of rhabdomyoma with focal cross-striations. Immunhistochemically, all applied muscular markers were positive. Electron microscopic studies confirmed the tumor's myogenic origin. Myofibrils with Z band material, abundant mitochondria and glycogen particles were observed. Treatment is usually complete excision. Local recurrences have been reported in some cases; malignant degeneration is not known.

Aged↗

PubMed2004

Epithelial hyaluronic acid and CD44v6 are mutually involved in invasion of colorectal adenocarcinomas and linked to patient prognosis.

Desmoplastic stroma of colorectal adenocarcinomas contains a variety of extracellular matrix molecules, including hyaluronic acid (HA). Overexpression of the HA receptor CD44 and, in particular, its splicing variant CD44v6 has been described as a prognostic factor for patients with colorectal adenocarcinomas in some studies, but converse reports also exist. Our hypothesis is that these divergent results may be related to the fact that the function of CD44v6 depends on the HA content of cell-surrounding matrix. Therefore, we studied the expression of HA and CD44v6 in tissue samples of 145 patients suffering from colorectal adenocarcinomas using immunohistochemistry. Expression of HA was separately evaluated in tumor epithelium and stroma. We additionally examined the influence of HA on invasion and adhesion of colorectal adenocarcinoma cells in vitro. The results show that epithelial HA expression was not correlated with tumor stage but with lymph-node or distant metastasis. Patients with tumors expressing epithelial HA had a decreased overall survival ( P=0.017) as well as tumors with coexpression of epithelial HA and CD44v6 ( P=0.011). The latter issue remained an independent prognostic factor in multivariate analysis (relative risk 5.06; 95% confidence interval, 1.18-21.57; P=0.028). HA exclusively stimulated in vitro invasion of CD44v6-expressing cells. This stimulation was partly reversed by an anti-CD44v6 antibody. Our findings suggest that the adverse prognostic effect of CD44v6 in colorectal adenocarcinoma might be restricted to those tumors that have pericellular HA.

Adenocarcinoma↗

PubMed2004

Expression of the ELAV-like protein HuR is associated with higher tumor grade and increased cyclooxygenase-2 expression in human breast carcinoma.

PURPOSE: The human ELAV (embryonic lethal abnormal vision)-like protein HuR stabilizes a certain group of cellular mRNAs that contain AU-rich elements in their 3'-untranslated region. Cell culture studies have shown that the mRNA of cyclooxygenase (COX)-2 can be stabilized by HuR. EXPERIMENTAL DESIGN: To investigate a possible contribution of dysregulation of mRNA stability to the progression of cancer and to overexpression of COX-2, we studied expression of HuR in 208 primary breast carcinomas by immunohistochemistry. RESULTS: There were two different staining patterns of HuR in tumor tissue of breast carcinomas: nuclear expression was seen in 61% of cases; and an additional cytoplasmic expression was seen in 30% of cases. Expression of HuR was significantly associated with increased COX-2 expression; this association was particularly significant for cytoplasmic HuR expression (P < 0.0005). We further observed a significant association of cytoplasmic (P = 0.002) or nuclear HuR (P = 0.027) expression with increased tumor grade. Only 13% of the grade 1 carcinomas showed cytoplasmic expression of HuR, compared with 46% of the grade 3 carcinomas. There was no significant correlation between HuR expression and other clinicopathological parameters such as histological type, tumor size, or nodal status as well as patient survival. CONCLUSIONS: Our results suggest that overexpression of HuR in tumor tissue may be part of a regulatory pathway that controls the mRNA stability of several important targets in tumor biology, such as COX-2. Based on our results, additional studies are necessary to investigate whether HuR might be a potential target for molecular tumor therapy.

Analysis of Variance↗

PubMed2004

Overexpression of the embryonic-lethal abnormal vision-like protein HuR in ovarian carcinoma is a prognostic factor and is associated with increased cyclooxygenase 2 expression.

The human embryonic-lethal abnormal vision-like protein HuR is involved in the regulation of mRNA turnover and serves as a shuttling protein between the nucleus and the cytoplasm that stabilizes mRNAs containing adenine- and uridine-rich elements in their 3' untranslated region. We have shown recently that expression of cyclooxygenase (COX)-2 is related to poor prognosis in ovarian carcinoma. Other studies have shown that the COX-2 mRNA contains an adenine- and uridine-rich element and is stabilized by HuR. In this study, we investigated the expression and cellular distribution of HuR in 83 primary ovarian carcinomas, 16 borderline tumors of the ovary, 3 normal ovaries, and 9 ovarian carcinoma cell lines. Expression of HuR was detected in all cell lines on the mRNA and protein level and showed a predominantly nuclear staining in OVCAR-3 cells by confocal microscopy. In an immunohistochemical evaluation of human ovarian carcinomas, HuR showed a nuclear expression in 81% of tumors. In addition, a cytoplasmic expression of HuR was observed in a subgroup of 45% of ovarian carcinomas. Nuclear as well as cytoplasmic expression of HuR was significantly increased in ovarian carcinomas compared with borderline tumors or normal ovaries. In univariate analysis, a significant association between cytoplasmic HuR expression and increased COX-2 expression (P = 0.025) as well as between histological grade (P = 0.008) and mitotic activity (P = 0.002) was observed, although nuclear expression of HuR was not correlated with COX-2 expression or other clinicopathological parameters. In Kaplan-Meier survival analysis, increased cytoplasmic expression of HuR was a significant prognostic indicator for progression-free survival (P = 0.03) as well as overall survival (P = 0.007). In multivariate analysis using the Cox regression model, cytoplasmic expression of HuR was an independent prognostic parameter for reduced overall survival with a relative risk of 2.62 (95% confidence interval, 1.32-5.19). Our results suggest that there is a dysregulation of cellular distribution of the mRNA stability factor HuR in a subset of invasive ovarian carcinomas. This dysregulation appears to result in an increased expression of COX-2, an increased proliferative rate, and may lead to a reduced survival time. Additional studies are required to analyze the downstream effects of increased cytoplasmic expression of HuR. In addition, it would be interesting to investigate the prognostic role of increased cytoplasmic expression of HuR in prospective studies.

Analysis of Variance↗

PubMed2004

Hepsin is highly over expressed in and a new candidate for a prognostic indicator in prostate cancer.

PURPOSE: Other cDNA microarray studies have shown that hepsin is one of the highly over expressed genes in prostate cancer tissue compared with nonmalignant and benign prostatic hyperplasia tissue. We quantitatively analyzed hepsin gene expression with real-time polymerase chain reaction and calculated its relationships with clinicopathological parameters in a large cohort of samples. MATERIALS AND METHODS: Matched prostate tissue samples from the cancerous and noncancerous parts of the same prostates were obtained from 90 patients with prostate cancer who underwent radical prostatectomy. Quantitative reverse transcriptase-polymerase chain reaction was performed using LightCycler Fast Start DNA Master SYBR Green I on a LightCycler (Roche Diagnostics GmbH, Mannheim, Germany) system. The ratio of hepsin-to-beta-actin (a housekeeping gene) was used to normalize data. RESULTS: Hepsin over expression in cancerous compared with noncancerous tissue was found in 81 of the 90 patient samples (90%, p <0.001). In 48 patients (53%) hepsin over expression was more than 10-fold in cancerous tissue. The ratio of cancerous-to-noncancerous hepsin expression was significantly higher in the 39 patients with grade 3 tumors compared with the 51 with grade 2 tumors (median 15.5 vs 9.6, p = 0.031). For the prognosis a cutoff at the 75th percentile provided a significant difference between patients at lower risk (pT2, G2 and Gleason score less than 7) and higher risk (pT3/4, G3 and Gleason score 7 or greater) for relapse. CONCLUSIONS: This report of the quantitative analysis of hepsin expression, which is the first to our knowledge, shows strong and significant over expression in prostate cancer tissue. Hepsin expression may be a new prognostic marker that could be used for assessing prostate cancer aggressiveness.

Adenocarcinoma↗

PubMed2004

Prognostic impact of cyclooxygenase-2 in breast cancer.

Cyclooxygenase (COX)-2, an inducible isoform of cyclooxygenases, regulates the rapid production of high levels of prostaglandins during inflammation. Cyclooxygenase-2 is overexpressed in a variety of malignant tumors. This review discusses epidemiologic and preclinical data on the role of COX-2 in the development and progression of breast cancer, and it will focus on recent studies that investigate the prognostic role of COX-2 in breast cancer. In rodent tumor models it has been shown that treatment with COX-1 or COX-2 inhibitors reduces incidence and growth of breast carcinomas. Possible mechanisms include regulation of invasion, increased proliferation, and suppression of apoptosis by COX-2. Moreover, there may be an indirect effect of prostaglandins, for example in tumor host interactions such as induction of stromal aromatase activity or enhancement of angiogenesis in tumor tissue. At least 8 different immunohistochemical studies have investigated expression of COX-2 in a total of 2392 primary breast carcinomas, of which 40% were found to be COX-2 positive. Overexpression of COX-2 is associated with indicators of poor prognosis, such as lymph node metastasis, poor differentiation, and large tumor size. Four studies have found that overexpression of COX-2 is linked to poor prognosis in breast cancer. These investigations provide the basis for further evaluation of a possible therapeutic effect of COX inhibitors in therapy of breast cancer.

Animals↗

PubMed2003

Induction of G0/G1 cell cycle arrest in ovarian carcinoma cells by the anti-inflammatory drug NS-398, but not by COX-2-specific RNA interference.

Cyclooxygenases, particularly COX-2, play an important role in tumor development and progression. We have previously shown that COX-2 expression is an independent prognostic factor in human ovarian carcinoma. In this study, we investigated the effects of the inhibition of COX isoforms by the NSAID NS-398 as well as by COX-isoform-specific RNA interference (RNAi) in the human ovarian carcinoma cell lines OVCAR-3 and SKOV-3. OVCAR-3 cells showed a constitutive expression of COX-1 and an induction of high levels of COX-2 and PGE(2) after stimulation with interleukin-1beta. In contrast, SKOV-3 cells were negative for both COX isoforms. In OVCAR-3 cells, PGE(2) production was inhibited by NS-398 in concentrations of 1 microM and by a COX-2-specific silencing RNA (siRNA), while a COX-1-specific siRNA did not have an effect. This suggests that COX-2 is the major source of PGE(2) in this cell line. To dissociate COX-2-specific and non-COX-2-specific effects on cell proliferation, a proliferation assay was performed after incubation of cells with NS-398 and COX siRNAs. NS-398 induced an inhibition of cell proliferation at concentrations of 50-500 microM, which are above the concentrations needed for the inhibition of PGE(2) production. This inhibitory effect was present in the COX-positive cell line OVCAR-3 as well as in the COX-negative cell line SKOV-3 and could not be reverted by addition of exogenous PGE(2). Neither COX-1- nor COX-2-specific siRNAs had an effect on cell proliferation of OVCAR-3 cells. Cell cycle analysis showed an increased accumulation of cells in the G0/G1 phase after treatment with NS-398, but not with COX siRNAs. These experiments suggest that NS-398 reduced cell proliferation in ovarian carcinoma cells by induction of G0/G1 cell cycle arrest independent of COX-2 inhibition. Our study shows that specific inhibition of COX isoforms by RNAi could be used to dissociate effects of NSAIDs. Furthermore, our results suggest that cell cycle arrest is one of the primary mechanisms responsible for the antiproliferative effects of NS-398 on ovarian carcinoma cells.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2003

Dynamic expression profile of p21WAF1/CIP1 and Ki-67 predicts survival in rectal carcinoma treated with preoperative radiochemotherapy.

PURPOSE: We investigated p53 and its downstream effectors p21WAF1/CIP1, BAX, and hMSH2 as well as the proliferation marker Ki-67 (mki-67/MIB-1) in patients undergoing preoperative radiochemotherapy for rectal carcinoma to identify prognostic and predictive factors. The focus of this study was on the dynamics of these genetic markers in a longitudinal study-that is, before and after radiochemotherapy. PATIENTS AND METHODS: Expression of p53, BAX, p21WAF1/CIP1, Ki-67, and hMSH2 was investigated by immunohistochemistry in pre- and posttherapeutic tumor samples in 66 patients. Tumor DNA was screened for p53 mutations by single-strand conformation polymorphism-polymerase chain reaction (SSCP-PCR). Paired tumor samples (pretherapy and posttherapy) were collected prospectively. RESULTS: Patients with a decrease in p21 expression following radiochemotherapy had better disease-free survival (P =.03). Similarly, patients with an increase in proliferative activity as measured by increased Ki-67 expression posttherapy had better disease-free survival (P <.005). In addition, we observed a significantly better prognosis for patients with high hMSH2 expression. In contrast, pretherapeutic levels of p53, BAX, or p21 expression and p53 mutation had no prognostic value, indicating that the combination of radiotherapy and chemotherapy might override defects in these genes. CONCLUSION: These findings are novel and support the clinical relevance of p21 in the suppression of both proliferation and apoptosis. Thus, the dynamic induction of p21WAF1/CIP1 was associated with a lower proliferative activity but an ultimately worse treatment outcome following neoadjuvant radiochemotherapy and tumor resection. Induction of p21, therefore, represents a novel resistance mechanism in rectal cancer undergoing preoperative radiochemotherapy.

Adult↗