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Biomedical subjects

Andrea Tannapfel

Publications and source records attributed to Andrea Tannapfel.

At least 37 records · Page 2Linked to original sources
PubMed2006

Intrafascial nerve-sparing endoscopic extraperitoneal radical prostatectomy.

OBJECTIVES: To present a modification of our previously published technique of nerve-sparing endoscopic extraperitoneal radical prostatectomy (nsEERPE). METHODS: The technique enables puboprostatic ligament preservation, leaving intact the puboprostatic ligaments, endopelvic fascia, periprostatic fascia, and neurovascular bundles (intrafascial dissection). The modification of nsEERPE was performed in 50 consecutive patients. RESULTS: The total operative time was 131 minutes (range 75 to 165). The mean catheterization time was 5.4 days (range 5 to 14). CONCLUSIONS: The intrafascial nsEERPE is a modification of our previously published standard nsEERPE. The anterior approach to the periprostatic fascia enables less traumatic dissection from the prostate and thus, theoretically, a more viable neurovascular bundle.

Aged↗
PubMed2006

Nerve-sparing endoscopic extraperitoneal radical prostatectomy: University of Leipzig technique.

PURPOSE: To describe the various operative steps as well as the functional and oncologic results of nerve-sparing endoscopic extraperitoneal radical prostatectomy (nsEERP). PATIENTS AND METHODS: One hundred twenty preoperatively potent patients have been treated with bilateral nsEERPE in our department. The average age of the patients was 60.3 years (range 41-74 years), and the mean prostate weight was 48.6 g (range 24-117 g). RESULTS: The mean operative time was 136 minutes (range 75-210 minutes). No conversions to open surgery were necessary. The mean catheterization time was 5.7 days (range 4-20 days). Lymphadenectomy was performed in 26 patients. The pathologic stages were pT2 in 78 and pT3 in 42 patients. Positive margins were detected in 7.7% (N = 6) and 19% (N = 8) of the patients with pT2 and pT3 disease, respectively. Erections sufficient for intercourse were reported in interviews with 58 patients (48.3%) during the 6-month follow-up period. Follow-up of at least 1 year is deemed necessary to draw more definite conclusions about erectile function. One week postoperatively, 32 patients (26.7%) required a maximum of 1 pad, 59 patients (49.2%) 2 or 3 pads, and 29 patients (24.2%) more than 3 pads per day because of incontinence, whereas 3 and 6 months after the procedure, 98 (82%) and 106 (88%) of the patients required a maximum of 1 pad, respectively. CONCLUSION: Our results demonstrate that nsEERPE can be performed with equal efficacy and preliminary results similar to those of standard open radical prostatectomy as well as transperitoneal laparoscopic prostatectomy while completely avoiding intraperitoneal complications.

Adult↗
PubMed2006

Impaired enteral levothyroxine absorption in hypothyroidism refractory to oral therapy after thyroid ablation for papillary thyroid cancer: case report and kinetic studies.

We present a 49-year-old patient suffering from hypothyroidism (thyrotropin [TSH], 20-80 mU/L) refractory to oral levothyroxine (LT(4)) substitution after total thyroidectomy and radioiodine therapy for papillary thyroid cancer. Extensive, repetitive work-up excluded small bowel, liver, and pancreatic disease and drug interactions. Triiodothyronine/thyroxine (T(3)/T(4)) antibodies were negative and reverse T(3) levels were normal. Supervised absorption tests of several LT(4) preparations in increasing dosages (250-1500 microg/d) confirmed an insufficient rise in serum T(4) levels following oral drug administration. Thus, intravenous LT(4) application (5 times per week) was commenced to restore at least normal range TSH levels. Repetition of absorption tests 1 year later, after a documented period of more than 3 months of stable euthyroidism, showed a considerable improvement of intestinal LT(4) uptake. Subsequently, the patient was managed on large doses of oral LT(4) (1500-2100 microg/d) alone, but this was found to be insufficient so that continuous intravenous LT(4) was administered via a morphine pump device to ultimately achieve stable euthyroidism. Of note, at 4-year follow-up there was no evidence of recurrent or metastasized papillary thyroid cancer. The reason for the disturbed intestinal LT(4) absorption in this patient remains unresolved. However, we would like to suggest the possibility of a specific intestinal uptake deficit, which will only become apparent in the case of previous thyroid ablation.

Administration, Oral↗
PubMed2006

New pieces of the pathogenetic mosaic in inflammatory bowel disease.

Ulcerative colitis (UC) is a lifelong disease. Patients with UC have an approximately 20% risk of developing colorectal cancer. The risk of neoplasia increases with the duration of the disease. Why some patients develop colorectal cancer and others do not is still poorly understood. UC patients who develop cancer have an underlying process of genetic and epigenetic instability in the inflamed mucosa, as indicated previously using several experimental techniques. Rapid cell turnover and oxidative injury observed in UC mucosa is associated with accelerated telomere shortening, followed by an increased potential for the chromosomal ends to fuse, ending in chromatin damage and chromosomal instability. It has been reported that chromosomal losses are greater and telomeres are shorter in the biopsies of patients with long-standing UC. Telomere length is correlated with chromosomal instability in a variety of epithelial preneoplastic lesions. In the case of an inflammatory context for UC mucosa, this genetic (and also epigenetic) damage may be associated with cellular transformation and tumour progression. However, almost all studies have focussed on the hypothesis that the epithelial cells are the primary target in this scenario, leading to epithelial types of cancer. The elongated lifespan of fibroblasts, as reported in the paper by Getliffe et al. in this issue of European Journal of Gastroenterology and Hepatology, is probably indirectly connected to a lesser frequency of colorectal neoplasia in UC as part of a different immune response in these patients compared with individuals with early-onset UC.

Age of Onset↗
PubMed2006

Novel targeted approaches to treating biliary tract cancer: the dual epidermal growth factor receptor and ErbB-2 tyrosine kinase inhibitor NVP-AEE788 is more efficient than the epidermal growth factor receptor inhibitors gefitinib and erlotinib.

Aberrant activation of the epidermal growth factor receptor is frequently observed in neoplasia, notably in tumors of epithelial origin. Attempts to treat such tumors with epidermal growth factor receptor antagonists resulted in remarkable success in recent studies. Little is known, however, about the efficacy of this therapy in biliary tract cancer. Protein expression of epidermal growth factor receptor, ErbB-2, and vascular endothelial growth factor receptor-2 was assessed in seven human biliary tract cancer cell lines by immunoblotting. In addition, histological sections from 19 patients with extrahepatic cholangiocarcinoma were analyzed for epidermal growth factor receptor, ErbB-2 and vascular endothelial growth factor receptor-2 expression by immunohistochemistry. Moreover, we sequenced the cDNA products representing the entire epidermal growth factor receptor coding region of the seven cell lines, and searched for genomic epidermal growth factor receptor amplifications and polysomy by fluorescence in-situ hybridization. Cell growth inhibition by gefitinib erlotinib and NVP-AEE788 was studied in vitro by automated cell counting. In addition, the anti-tumoral effect of erlotinib and NVP-AEE788 was studied in a chimeric mouse model. The anti-tumoral drug mechanism in this model was assessed by MIB-1 antibody staining, terminal deoxynucleotidyl transfer-mediated dUTP nick end-labelling assay, von Willebrand factor staining, and immunoblotting for p-p42/44 (p-Erk1/2, p-MAPK) and p-AKT. Immunoblotting revealed expression of epidermal growth factor receptor, ErbB-2, and vascular endothelial growth factor receptor-2 in all biliary tract cancer cell lines. EGFR was detectable in six of 19 (32%) extrahepatic human cholangiocarcinoma tissue samples, ErbB-2 in 16 of 19 (84%), and vascular endothelial growth factor receptor-2 in nine of 19 (47%). Neither epidermal growth factor receptor mutations nor amplifications or polysomy were found in the seven biliary tract cancer cell lines. Gefitinib, erlotinib and NVP-AEE788 caused a significant growth inhibition in vitro; however, there was a significant difference in efficacy (NVP-AEE788>erlotinib>gefitinib). After 14 days of in-vivo treatment, using the chimeric mouse model, tumors had a significantly reduced volume and mass after NVP-AEE788, but not after erlotinib treatment, as compared with placebo. Reduction of proliferation (signalling via the mitogen-activated protein kinase pathway), induction of apoptosis and inhibition of angiogenesis were the main mechanisms of drug action. No significant reduction of anti-apoptotic AKT phosphorylation, however, occurred, which may be a possible counter mechanism of the tumor. Epidermal growth factor receptor, ErbB-2, and vascular endothelial growth factor receptor-2 expression was detectable in biliary tract cancer, and receptor inhibition exerts marked effects on tumor growth in vitro and in vivo, which was strongest for the dual EGFR/ErbB-2 inhibitor NVP-AEE788. Therefore, further clinical evaluation of this new drug for the treatment of biliary tract cancer is recommended.

Animals↗
PubMed2006

p16, p14, p53, and cyclin D1 expression and HPV analysis in small cell carcinomas of the uterine cervix.

Small cell carcinomas (SmCCs) of the uterine cervix are rare tumors. The knowledge regarding protein expression of several checkpoint candidates of cell cycle regulation is limited. Surgically treated SmCCs were selected from our files for immunohistochemical staining (neuroendocrine markers, p53, p16, p14, and cyclin D1). Polymerase chain reaction analysis, using general primers, was performed for human papillomavirus analysis. Nine of 677 tumors (1.3%) were classified as SmCCs after Grimelius staining (8/9 tumors positive) and immunohistochemical reaction against neurone-specific enolase, chromogranin A, synaptophysin (7/9 positive tumors), and CD 56 (8/9 positive tumors). All specimens were positive for at least two of the above. Two SmCCs were p53 positive and one case was p14 positive. Cyclin D1 staining was completely negative. All cases showed strong nuclear and/or cytoplasmic p16-immunostaining. Seven tumors represented human papillomavirus positivity for high-risk types. Four patients died of the tumor after a median time of 36.7 months (range, 15-56 months), representing a 5-year survival rate of 56%. The results suggest that p16 is up-regulated or accumulated in the SmCCs of the uterine cervix, probably caused by infection with human papillomavirus. p14 inactivation is of high prevalence in SmCCs and detection rate of p53 is similar to other histologic types of cervical carcinomas.

Adult↗
PubMed2006

Surgical and palliative management and outcome in 184 patients with hilar cholangiocarcinoma: palliative photodynamic therapy plus stenting is comparable to r1/r2 resection.

OBJECTIVE: First, to analyze the strategy for 184 patients with hilar cholangiocarcinoma seen and treated at a single interdisciplinary hepatobiliary center during a 10-year period. Second, to compare long-term outcome in patients undergoing surgical or palliative treatment, and third to evaluate the role of photodynamic therapy in this concept. SUMMARY BACKGROUND DATA: Tumor resection is attainable in a minority of patients (<30%). When resection is not possible, radiotherapy and/or chemotherapy have been found to be an ineffective palliative option. Recently, photodynamic therapy (PDT) has been evaluated as a palliative and neoadjuvant modality. METHODS: Treatment and outcome data of 184 patients with hilar cholangiocarcinoma were analyzed prospectively between 1994 and 2004. Sixty patients underwent resection (8 after neoadjuvant PDT); 68 had PDT in addition to stenting and 56 had stenting alone. RESULTS: The 30-day death rate after resection was 8.3%. Major complications occurred in 52%. The overall 1-, 3-, and 5-year survival rates were 69%, 30%, and 22%, respectively. R0, R1, and R2 resection resulted in 5-year survival rates of 27%, 10%, and 0%, respectively. Multivariate analysis identified R0 resection (P < 0.01), grading (P < 0.05), and on the limit to significance venous invasion (P = 0.06) as independent prognostic factors for survival. PDT and stenting resulted in longer median survival (12 vs. 6.4 months, P < 0.01), lower serum bilirubin levels (P < 0.05), and higher Karnofsky performance status (P < 0.01) as compared with stenting alone. Median survival after PDT and stenting, but not after stenting alone, did not differ from that after both R1 and R2 resection. CONCLUSION: Only complete tumor resection, including hepatic resection, enables long-term survival for patients with hilar cholangiocarcinoma. Palliative PDT and subsequent stenting resulted in longer survival than stenting alone and has a similar survival time compared with incomplete R1 and R2 resection. However, these improvements in palliative treatment by PDT will not change the concept of an aggressive resectional approach.

Adult↗
PubMed2006

Antiviral treatment withdrawal in viremic HCV-positive liver transplant patients: impact on viral loads, allograft function and morphology.

BACKGROUND: The aim of this study was to evaluate the clinical long-term consequences of antiviral treatment discontinuation in viremic hepatitis C virus (HCV)-positive liver transplant recipients. METHODS: Twenty-five HCV-positive patients after liver transplantation were included in this study. After diagnosing recurrent hepatitis C, a combination therapy with interferon-alpha2b and ribavirin for a minimum of 12 months was initiated. Viremia levels and allograft function were monitored continuously. Allograft biopsies were performed yearly, analyzing grading of inflammation and staging of fibrosis. RESULTS: HCV recurrence rate was 100%. Up to 114 months post-transplantation, sustained virological response rate was 64%. Treatment discontinuation in virological nonresponders led subsequently to a significant increase of viral loads and deterioration of allograft function (P<0.05) within 1 month. In three patients, a fibrosing cholestatic syndrome developed, resulting in one patient death. Antiviral retherapy was maintained for a mean of 33 months, leading to a significant decline of aminotransferases (P<0.05) as well as decreasing serum levels of bilirubin and HCV-RNA within 6 months. In addition, development of severe allograft fibrosis was prevented despite persistent viral loads. CONCLUSION: Our study suggests that antiviral treatment withdrawal carries the risk of severe disease progression in persistently viremic HCV-positive liver transplant patients.

Adult↗
PubMed2006

Expression of toxin-related human mono-ADP-ribosyltransferase 3 in human testes.

AIM: To investigate wether the corresponding protein of mono-ADP-ribosyltransferase 3 (ART3) mRNA is expressed in human testes and, if so, whether the expression is cell type-specific. METHODS: ART3 mRNA was determined in human testes and sperm by reverse transcription-polymerase chain reaction (RT-PCR). The glycosyl-phosphatidylinositol linkage of ART3 was shown by treating ART3-transfected HEK-293-T cells with phospholipase C. Fluorescent activated cell sorter (FACS)-analyses were used to detect ART3 on mature spermatozoa and immunohistological studies to detect the protein in testes. RESULTS: ART3 protein was shown to be present in testes. It was found on spermatocytes only. It was absent from spermatogonia, spermatids and spermatozoa. The absence of ART3 from spermatozoa was confirmed by FACS-analysis. ART3 protein was detected neither within a seminoma nor on Leydig cells. CONCLUSION: Here we show for the first time that ART3 protein is expressed in testes in particular on spermatocytes, indicating that ART3 exerts a specific function only required at a particular stage of spermatogenesis.

ADP Ribose Transferases↗
PubMed2006

Does the expression of c-kit (CD117) in neuroendocrine tumors represent a target for therapy?

Neuroendocrine tumors are very heterogeneous, develop from a variety of tissues, and can be difficult to diagnose. Without the clinical manifestation of metastases, it is often difficult to characterize them as malignant. Even so-called completely (R0) resected tumors can spread clinically visible metastases within a few months after initial surgery. Treatment options for neuroendocrine tumors including pheochromocytoma are limited. Molecular targeted therapies using tyrosine kinase inhibitors might prove to be helpful in patients with these tumors. In an immunohistochemical study, we examined KIT in 26 pheochromocytomas, 8 of which were malignant (3 adrenal pheochromocytomas, 5 paragangliomas). KIT expression was found in one of these 8 malignant tumors. This 2.5-cm-large adrenal pheochromocytoma originated from a woman with neurofibromatosis type 1 and spread into spine, skull, and lung. KIT expression could be demonstrated in 5% of tumor cells. On the basis of KIT expression immunohistochemically, we treated patients with neuroendocrine (i.e., medullary thyroid cancer) and other tumors with imatinib 400 mg per day, but without efficacy after 2 months of therapy. Similar results were shown by other investigators. Therefore, monotherapy with imatinib may not be efficacious in patients with neuroendocrine tumors that express KIT. Tyrosine kinase inhibitors such as sorafenib that targets several receptors in addition to KIT may be more efficacious in treating patients with neuroendocrine tumors.

Humans↗
PubMed2006

E-cadherin and DAP kinase in pancreatic adenocarcinoma and corresponding lymph node metastases.

E-cadherin and DAP kinase have been implicated as 'invasion suppressor' genes in human cancer. The aim of this study was to analyze the methylation status of E-cadherin and DAP kinase and the expression of the protein in the metastatic lesions and to compare it with the expression in the primary tumor. Methylation-specific PCR of the DAP kinase and E-cadherin promoter was performed in 28 primary adenocarcinomas of the pancreas and in 13 corresponding regional lymph node metastases. The presence of E-cadherin and DAP kinase protein was assessed by immunohistochemistry. Metastatic lymph nodes showed a significant different expression profile from the primary tumor. E-cadherin methylation was observed in 8/28 (29%) and loss of protein expression was observed in 16/28 (57%) of pancreatic carcinomas. E-cadherin methylation was observed in 7/13 (54%) and loss of protein expression was observed in 11/13 (85%) lymph node metastases (p=0.047). DAP kinase methylation occurred in 11/28 (39%) pancreatic carcinomas and loss of protein expression was observed in 13/28 (46%). DAP kinase was methylated in 6/13 (46%) lymph node meta-stases and loss of protein expression was observed in 10/13 (77%) (p=0.039). Comparing primary tumor and corresponding lymph node metastases in 13 cases, the status of E-cadherin methylation was discordant in 2 cases. The protein expression pattern of E-cadherin and DAP kinase was discordant in 4 and 3 cases respectively. Unmethylated tumor samples did not express E-cadherin in 12 and DAP kinase protein in 6 cases. Our results demonstrate that reduction of E-cadherin and DAP kinase expression is more frequent in lymph node metastases than in the primary tumor and methylation of the promoter region contributes to this reduction; however, an alternative mechanism of inactivation seems to exist.

Adenocarcinoma↗
PubMed2005

SOCS-3 is frequently methylated in head and neck squamous cell carcinoma and its precursor lesions and causes growth inhibition.

The suppressors of cytokine signaling (SOCS) are inhibitors of cytokine signaling that function via the Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway. Recently, methylation of SOCS-1 and SOCS-3 has been implicated in the tumorigenesis of liver and lung cancer. This study was performed to elucidate the role of SOCS-1 and SOCS-3 in squamous cell carcinoma of the head and neck (HNSCC) and its precursor lesions. HNSCC of 94 patients and corresponding normal mucosa, lymph node metastases as well as 16 high- and 21 low-grade squamous cell dysplasias were studied by using methylation-specific PCR (MSP) for the SOCS-1 and SOCS-3 promoter after microdissection. The presence of SOCS-3 mRNA transcripts was confirmed by semiquantitative real-time PCR, and the SOCS-3 protein was analysed immunohistochemically. SOCS-3 hypermethylation was found in 85/94 HNSCC (90%) and in 10/16 high-grade and 9/21 low-grade dysplasias (63 and 43%, respectively). SOCS-1 promoter hypermethylation was detected in 10/94 HNSCC samples (11%) and in 2/16 high-grade and 1/21 low-grade dysplasias (13 and 5%, respectively). Lymph node metastases exhibited an identical methylation status as the primary tumors. Methylation of the SOCS-3 promoter correlated with downregulation of SOCS-3 transcripts and protein expression in these tumors and various cell lines. In the cell lines tested, SOCS-3 and SOCS-1 transcripts increased upon treatment with the demethylation compound 5-aza-2-deoxycytidine (5-AZA-DC). Overexpression of wild-type SOCS-3 in carcinoma cells with methylated SOCS-3 resulted in the induction of apoptosis and growth suppression as well as downregulation of STAT3, bcl-2 as well as bcl-xL. Our data suggest that promoter methylation and subsequent transcript downregulation of SOCS-3 transcripts and, to a much lesser extent, SOCS-1 are involved in the multistep carcinogenesis of HNSCC. During its involvement in tumor growth, restoration of SOCS-3 may hold treatment potential for HNSCC.

Base Sequence↗
PubMed2005

Mutations of the BRAF gene in ulcerative colitis-related colorectal carcinoma.

The Raf/MEK/ERK (MAPK) signal transduction cascade is an important mediator of a number of cellular fates including growth, proliferation and survival. The BRAF gene is activated by oncogenic Ras, leading to cooperative effects in cells responding to growth factor signals. Our study was performed to elucidate a possible function of BRAF in ulcerative colitis (UC)-related colorectal carcinogenesis. Mutations of BRAF and KRAS were determined in 33 UC-related colorectal cancers by direct DNA sequencing analyses after microdissection. Mismatch-repair deficiency was assessed by immunohistochemistry for major mismatch-repair proteins hMLH1, hMSH2 and hMSH6 and microsatellite analyses of the BAT25 and BAT26 loci. Hypermethylation of the hMLH1 promoter was also tested. The results obtained were correlated with histopathologic variables. Activating BRAF missense mutations were identified in 3/33 UC-related cancers (9%), 2 of which exhibited a loss of hMLH1-protein expression and hypermethylation of the hMLH1 promoter. Corresponding nondysplastic UC-mucosa of these patients did not show BRAF mutations. KRAS mutations were found in 6/33 (18%) UC cancers. All 6 UC cancers with KRAS mutations had an intact BRAF gene as the 3 cancers with BRAF mutations had an intact KRAS gene. There was no significant correlation between BRAF or KRAS status and clinicopathologic variables. Our data indicate that BRAF mutations are not an initiating event in UC-related carcinogenesis and are associated with mismatch-repair deficiency through hMLH1-promoter hypermethylation. Disruption of the Raf/MEK/ERK (MAPK) kinase pathway-either through RAS or BRAF mutation-was detected in 27% of all UC-related cancers and thus plays an important role in UC-related carcinogenesis.

Adult↗
PubMed2005

Allele loss and epigenetic inactivation of 3p21.3 in malignant liver tumors.

Previously, the RASSF1A, BLU and SEMAPHORIN 3B (SEMA3B) candidate tumor suppressor genes on chromosome 3p21.3 were found to be inactivated and downregulated by genetic and epigenetic changes in lung cancer. We analyzed the methylation status of RASSF1A, BLU and SEMA3B in 35 hepatocellular carcinomas (HCCs) and 15 cholangiocarcinomas (CCs) by methylation-specific PCR and loss of heterozygosity (LOH) at 3p21.3 after microdissection. The presence of mRNA transcripts was confirmed by semiquantitative PCR. SEMA3B hypermethylation was found in 29/35 HCCs (83%) and in all (15/15) patients with CC. BLU promoter hypermethylation was detected in 7/35 (20%) HCCs and 3/15 (20%) CCs. In 2 corresponding specimens of hepatitis B virus-related liver cirrhosis, BLU methylation was also observed, but not in uninvolved normal liver tissue. RASSF1A was methylated in 21/35 HCCs (60%) and in 10/15 CCs (67%). LOH at 3p21.3 occurred in 8/35 (23%) HCCs and 3/15 (20%) CCs. The presence of hypermethylation was statistically associated with LOH of SEMA3B and correlated with downregulation of mRNA transcripts. SEMA3B transcripts increased upon treatment of HCC cell lines with the demethylation compound 5-aza-2-deoxycytidine. In conclusion, our data indicate that 2-hit gene silencing of SEMA3B through epigenetic changes and allele loss is a common and important event in the carcinogenesis of malignant liver tumors.

Aged↗
PubMed2005

TNP-470 fails to block the onset of angiogenesis and early tumor establishment in an intravital minimal disease model.

BACKGROUND AND AIMS: The angiogenesis inhibitor TNP-470 (AGM-1470) has shown encouraging results in animal models of established tumors. However, results of recent clinical trials using TNP-470 have been disappointing. Since little is known about the effects of TNP-470 at the minimal disease stage, we analyzed the effects of TNP-470 on the early stages of tumor establishment. METHODS: Twenty thousand green fluorescent protein (GFP)-transfected murine CT-26 (colonic carcinoma) or Panc-02-H0 (pancreatic adenocarcinoma) cells were inoculated in dorsal skin-fold chambers in BALB/c or C57BL6 mice. Tumor area and microvessel density (MVD) were quantified by intravital microscopy (IVM). Body weight was also monitored. Effects were compared with those in a conventional model involving subcutaneous (s.c.) inoculation of 10(6) tumor cells, followed by measurement of tumor volume, endogenous plasma VEGF/endostatin (ELISA) and proliferation/apoptosis/microvessel density (Ki-67/TUNEL/CD-34). TNP-470 was injected s.c. over the 10-day experimental period (30 mg/kg every 2 days [n=6] to 100 mg/kg/day [n=5 dorsal skin-fold chamber model, n=4 s.c. tumor model]). RESULTS: At 30 mg/kg/every second day neither CT-26 nor PANC-02-H0 tumors were inhibited in neither of the two models. TNP-470 dosage was escalated in CT-26-bearing animals until an antiangiogenic effect could be observed. In the IVM model, only TNP-470 100 mg/kg/day reduced MVD (P=0.006), but failed to block the onset of angiogenesis and tumor area increase. Body weight decreased by 25% (P<0.05). In the subcutaneous tumor model, tumor growth was reduced (P=0.045) but not blocked, while vascular endothelial growth factor (VEGF)/endostatin synthesis and Ki67/TUNEL/CD-34 were not significantly affected. CONCLUSION: While capable of reducing tumor growth in a conventional model, treatment with TNP-470 does not block the onset of angiogenesis and tumor establishment in a model of minimal disease. When used as a single agent TNP-470 does not control minimal tumor disease in experimental colonic carcinoma.

Angiogenesis Inhibitors↗
PubMed2005

TAp63gamma can substitute for p53 in inducing expression of the maspin tumor suppressor.

Maspin is a Class II tumor suppressor protein and plays a role in tumor growth by inhibiting cellular invasion and motility. It is a member of the serpin family of protease inhibitors and has been shown to reduce angiogenesis. Maspin gene expression can be upregulated by the tumor suppressor p53. We tested 7 p53-related proteins of the p63 and p73 families for their ability to induce maspin expression. The p63 splice form TAp63gamma can substitute for p53 in activating the maspin promoter. TAp63gamma activates the promoter through the same consensus site as p53. In the DLD-1 colorectal adenocarcinoma cell line, harboring a tet-off regulated transgene, induction of TAp63gamma leads to an upregulation of maspin mRNA from the chromosomal gene. With a short lag phase also maspin protein levels are elevated after induced TAp63gamma expression. To assess a potential function of p63-dependent maspin upregulation in tumors we followed expression of p53, p63 and maspin by immunohistochemistry in hepatocellular carcinomas. Two types of tumors with wild-type or mutant p53 were assayed. Interestingly, the majority of tumors expressing only a mutated and inactive p53 protein nonetheless stain positive for maspin, whereas these tumors were positive for p63 protein expression. In summary, we show that TAp63gamma can substitute for p53 in transcriptional activation of the maspin tumor suppressor gene. TAp63gamma employs the same DNA recognition site for this activation as p53. We observe expression patterns of p53, p63 and maspin proteins in tumor tissue that may indicate also a function of maspin induction by p63 in tumors.

Alternative Splicing↗
PubMed2005

Mutations of BRAF and RAS are rare events in germ cell tumours.

The BRAF gene, one of the human isoforms of RAF, is activated by oncogenic Ras, leading to cooperative effects in cells responding to growth factor signals. Recently, somatic missense mutations in the BRAF gene have been detected in a variety of human tumors. We have studied male germ cell tumours (GCT) for probable mutations of the BRAF and Ras oncogene. Microsatellite instability (MSI) was analysed using mono- or di-nucleotide marker. Mutational analysis of 62 GCT (30 seminomas and 32 nonseminomas) was performed after microdissection of the different tumour components. The expression of Erk1/2, an important downstream point of convergence in the Ras-RAF-MEK-Erk pathway was assessed immunohistochemically. Activating BRAF missense mutations were identified in 3 out of 32 cases of nonseminomas (9%) but not in seminomas. The mutations were 1796T>A mutations and were found within the embryonic carcinoma component of these tumors. Two out of 30 seminomas (7%) and 3 out of 32 nonseminomas (9%) exhibited KRAS gene mutations. MSI was observed in 4 out 62 tumours (7%) [1 seminoma and 3 nonseminomas (embryonal carcinoma)]. All of the microsatellite instable embryonal carcinomas had a mutated BRAF gene. All 5 GCT with RAS mutations had an intact BRAF gene. We identified constitutively activated Erk in almost all tumours tested. Our data indicate that BRAF gene mutations are a rare event in GCT and are independent of KRAS mutations. In embryonal carcinomas, BRAF mutations may be linked to the proficiency of these tumours in repairing mismatched bases in DNA. The finding of activated Erk suggests a causative role for MAPK activation in GCT independent of activating BRAF or RAS mutations.

DNA Mutational Analysis↗