Advantages of a multi-state approach in surgical research: how intermediate events and risk factor profile affect the prognosis of a patient with locally advanced rectal cancer.

BACKGROUND: Standard survival analysis fails to give insight into what happens to a patient after a first outcome event (like first relapse of a disease). Multi-state models are a useful tool for analyzing survival data when different treatments and results (intermediate events) can occur. Aim of this study was to implement a multi-state model on data of patients with rectal cancer to illustrate the advantages of multi-state analysis in comparison to standard survival analysis. METHODS: We re-analyzed data from the RCT FOGT-2 study by using a multi-state model. Based on the results we defined a high and low risk reference patient. Using dynamic prediction, we estimated how the survival probability changes as more information about the clinical history of the patient becomes available. RESULTS: A patient with stage UICC IIIc (vs UICC II) has a higher risk to develop distant metastasis (DM) or both DM and local recurrence (LR) if he/she discontinues chemotherapy within 6 months or between 6 and 12 months, as well as after the completion of 12 months CTx with HR 3.55 (p = 0.026), 5.33 (p = 0.001) and 3.37 (p < 0.001), respectively. He/she also has a higher risk to die after the development of DM (HR 1.72, p = 0.023). Anterior resection vs. abdominoperineal amputation means 63% risk reduction to develop DM or both DM and LR (HR 0.37, p = 0.003) after discontinuation of chemotherapy between 6 and 12 months. After development of LR, a woman has a 4.62 times higher risk to die (p = 0.006). A high risk reference patient has an estimated 43% 5-year survival probability at start of CTx, whereas for a low risk patient this is 79%. After the development of DM 1 year later, the high risk patient has an estimated 5-year survival probability of 11% and the low risk patient one of 21%. CONCLUSIONS: Multi-state models help to gain additional insight into the complex events after start of treatment. Dynamic prediction shows how survival probabilities change by progression of the clinical history.

[Validity of Recommendations for Secondary Prevention of Colon Cancer]. / Validität der Empfehlungen zur Sekundärprävention von Dickdarmkrebs.

BACKGROUND: Prevention programmes should only be recommended if they achieve what they promise to achieve. Therefore, we checked the variation and validity of recommendations for screening for colorectal cancer of nine organisations. METHODS: We analysed the information concerning recommended screening age, guaiac faecal occult blood test (gFOBT), faecal immunological test (FIT), faecal DNA test, sigmoidoscopy, colonoscopy, double-contrast examination/double-contrast barium enema, and virtual colonoscopy/CT colonography in the following three steps: 1) we gathered the references quoted by the nine organisations; 2) references were categorised according to mortality, incidence and sensitivity/specificity; 3) the validity of references that reported reduced mortality attributed to screening were evaluated. RESULTS: Evidence of occult faecal blood was the only screening method recommended by all nine organisations. Colonoscopy was recommended by seven organisations. Fifteen of the 33 references used endpoints other than mortality to justify screening. One publication was a meta-analysis. Eleven of 17 publications evaluated the gFOBT, three evaluated sigmoidoscopy, one FIT, one coloscopy, and one general diagnosis of the intestine. On average, two of nine validity criteria were completely fulfilled, five only partially, and two were not fulfilled. In two publications, none of the validity criteria were completely met. CONCLUSION: Analysis of screening for colorectal cancer revealed that nine organisations had different goals and different recommendations. Scrupulous and thorough evaluation of the scientific studies in relation to mortality, upon which these recommendations are based, revealed numerous shortcomings and therefore could not sufficiently substantiate the international recommendations for screening for colorectal cancer. It would be useful to establish a consensus about which data have to be collected to provide a reliable basis for health-care decisions.

Factors influencing the course of acute appendicitis in adults and children.

PURPOSE: Our aim was to determine predictive factors for the diagnosis and postoperative complications of acute appendicitis. MATERIALS AND PATIENTS: Data sets of 1,439 consecutive adults and children who had an appendectomy between 1999 and 2008 were retrospectively analyzed. RESULTS: A mild acute appendicitis was present in 50 % (n = 722) and a severe acute appendicitis in 25 % (n = 355) of the patients. No signs of any pathology were found in 6 % (n = 82). Gender, white blood count (WBC), C-reactive protein (CRP), and ultrasound (US) examination were important indicators of mild acute and severe acute appendicitis in adults and children. Postoperative complications occurred in 16 % (237/1,439), mainly consisting of wound infections (8 %, n = 122) and bowel dysfunction (5 %, n = 76). Sixty-two patients (4.3 %) required reoperations. One patient died (1/1,439, 0.07 % mortality rate). Age, pathology, and the presence of bacteria in the intraoperative swab were important predictive factors for postoperative complications in adults and children. Time since onset of symptoms and type of operation were also associated with postoperative complications among adults. Complications developed in 21 and 9 % of the adults (155/754 and 10/125) who had open and laparoscopic surgery, respectively. CONCLUSIONS: Besides history and clinical examination, WBC, CRP, and US examination remain important factors for diagnosing acute appendicitis. Complications are related to the pathology, presence of bacteria, and type of operation. Early diagnosis within 48 h may be important. A laparoscopic procedure in adults may also cause fewer wound infections.

[Incidence of, risk factors for, and prevention of intestinal leakage]. / Inzidenz, Risikofaktoren und Prävention der intestinalen Nahtinsuffizienz.

BACKGROUND: Intestinal anastomotic leakage represents a major complication in visceral surgery with relevant morbidity and mortality. MATERIAL AND METHODS: Based on a literature -search in Medline / PubMed the available data are presented, critically reviewed and summarised. RESULTS AND CONCLUSION: Beside optimisation of surgical technique, patient-dependent risk factors - such as relevant comorbidity, certain medications or previous radiochemotherapy - play a major role in the development of anastomotic leak-age. The effort for optimisation of these patient-dependent risk factors is not incorporated within the compensation scheme in German hospitals.

Impact of FDG-PET computed tomography for surgery of recurrent or persistent differentiated thyroid carcinoma.

Fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) is able to localize persistent or recurrent disease in differentiated thyroid carcinoma (DTC). The aim of the study was to correlate PET/CT results with precise intraoperative localization of persistent or recurrent papillary and follicular thyroid carcinoma. Patients with differentiated thyroid carcinoma who received FDG-PET scans were prospectively documented. The PET/CT results were correlated with other localization studies (neck ultrasound, ¹³¹I whole-body scan) and accurately compared to intraoperative findings and histopathological examinations. FDG-PET/CT scans were performed in 18 patients, between 16 and 84 years of age, from December 2008 to June 2011. Fourteen patients had papillary thyroid carcinomas and 4 had follicular thyroid carcinomas. All patients had a previous thyroidectomy and radioiodine ablation. Before cervical re-exploration, FDG-PET/CT-positive findings were reported in 14 individuals, whereas 4 PET scans provided no evidence of disease. Intraoperatively, 13 of 14 FDG-PET/CT-positive localizations of recurrent or persistent thyroid carcinomas were verified and confirmed by histopathology (sensitivity 93%). In another patient lymph node metastases of lung cancer were detected intraoperatively. However, FDG-PET/CT underestimated the number of lesions in 5 of 6 patients undergoing systematic lymphadenectomy. No lymph node or soft tissue metastases were found intraoperatively in 3 of the 4 patients with negative FDG-PET scans. A solitary cystic lymph node metastasis was found in the fourth patient but was not detected by FDG-PET/CT (specificity 75%). FDG-PET/CT has high sensitivity and specificity for the detection of persistent or recurrent differentiated thyroid carcinoma. FDG-PET/CT helps to select patients who might benefit from surgery because it provides precise anatomical details.

[A 31-year-old pregnant woman with refractory hypercalcemia]. / 31-jährige Schwangere mit refraktärer Hyperkalzämie.

A 31-year-old pregnant woman presented with refractory severe hypercalcemia due to an advanced neuroendocrine tumor masquerading as hyperemesis gravidarum. Octreotide therapy and extensive tumor debulking surgery resulted in symptom control. After a prolonged stay in the intensive care unit due to parapneumonic acute respiratory distress syndrome, the patient delivered a healthy child. Neuroendocrine tumors are a rare complication of pregnancy and a seldom cause of refractory hypercalcemia.

Pharmacokinetics of ertapenem in colorectal tissue.

BACKGROUND: There are only limited data on tissue kinetics of ertapenem in colorectal tissue more than 3 h after administration of the drug. The purpose of this study was to assess the pharmacokinetics (PK) of ertapenem in colorectal tissue via population PK modeling. PATIENTS AND METHODS: Patients ≥18 years requiring surgical intervention at the colon and/or rectum were eligible (ClinicalTrials.gov identifier: NCT 00535652). Tissue and blood samples were taken during surgery after a single dose of 1 g ertapenem. Ertapenem concentration was determined by high-performance liquid chromatography/mass spectrometry. Population PK modeling was performed in S-ADAPT. RESULTS: Twenty-three patients were enrolled. The highest tissue concentration was 6.4 ± 2.3 mg/kg, the highest total plasma concentration 51.34 ± 9.4 mg/l, the highest unbound plasma concentration 7.05 ± 1.1 mg/l, and the unbound fraction in plasma was 14-15% for total ertapenem concentrations below approximately 22 mg/l, 19% at 100 mg/l, and 25% at 250 mg/l. The estimated geometric mean terminal half-life was 2.5 h for plasma and tissue. In the Monte Carlo simulation, a single dose of 1,000 mg ertapenem achieved robust (≥90%) probabilities of target attainment up to a minimum inhibitory concentration (MIC) of approximately 2 mg/l for the bacteriostasis target (free time above MIC, fT(>)(MIC) = 20%) and up to 0.25-0.5 mg/l for the near-maximal killing target (40% fT(>)(MIC)). CONCLUSION: Our data indicate an adequate penetration of ertapenem into uninfected colorectal tissue up to 8.5 h (35% of the dosing interval) after administration of 1 g intravenously.

Inhibition of endogenous SPARC enhances pancreatic cancer cell growth: modulation by FGFR1-III isoform expression.

BACKGROUND: Secreted protein acidic and rich in cysteine (SPARC) is a multi-faceted protein-modulating cell-cell and cell-matrix interactions. In cancer, SPARC can be not only associated with a highly aggressive phenotype, but also acts as a tumour suppressor. The aim of this study was to characterise the function of SPARC and its modulation by fibroblast growth factor receptor (FGFR) 1 isoforms in pancreatic ductal adenocarcinoma (PDAC). METHODS AND RESULTS: Exogenous SPARC inhibited growth, movement, and migration. ShRNA inhibition of endogenous SPARC in ASPC-1 and PANC-1 cells resulted in increased anchorage-dependent and -independent growth, transwell migration, and xenograft growth as well as increased mitogenic efficacy of fibroblast growth factor (FGF) 1 and FGF2. Endogenous SPARC expression in PANC-1 cells was increased in FGFR1-IIIb over-expressing cells, but decreased in FGFR1-IIIc over-expressing cells. The up-regulation of endogenous SPARC was abrogated by the p38-mitogen-activated protein kinase inhibitor SB203580. SPARC was detectable in conditioned medium of pancreatic stellate cells (PSCs), but not PDAC cells. Conditioned medium of PDAC cells reduced endogenous SPARC expression of PSCs. CONCLUSION: Endogenous SPARC inhibits the malignant phenotype of PDAC cells and may, therefore, act as a tumour suppressor in PDAC. Endogenous SPARC expression can be modulated by FGFR1-III isoform expression. In addition, PDAC cells may inhibit endogenous SPARC expression in surrounding PSCs by paracrine actions.

Adjuvant chemoradiotherapy of advanced resectable rectal cancer: results of a randomised trial comparing modulation of 5-fluorouracil with folinic acid or with interferon-α.

BACKGROUND: Standard adjuvant chemoradiotherapy of rectal cancer still consists of 5-fluorouracil (5-FU) only. Its cytotoxicity is enhanced by folinic acid (FA) and interferon-α (INFα). In this trial, the effects of FA and IFNα on adjuvant 5-FU chemoradiotherapy in locally advanced rectal cancer were investigated. METHODS: Patients with R(0)-resected rectal cancer (UICC stage II and III) were stratified and randomised to a 12-month adjuvant chemoradiotherapy with 5-FU, 5-FU+FA, or 5-FU+IFNα. All patients received levamisol and local irradiation with 50.4 Gy. RESULTS: Median follow-up was 4.9 years (n=796). Toxicities (WHO III+IV) were observed in 32, 28, and 58% of patients receiving 5-FU, 5-FU+FA, and 5-FU+IFNα, respectively. No differences between the groups were observed for local or distant recurrence. Five-year overall survival (OS) rates were 60.3% (95% confidence interval (CI): 54.3-65.8), 60.4% (54.4-65.8), and 59.9% (53.0-66.1) for 5-FU, 5-FU+FA, and 5-FU+IFNα, respectively. A subgroup analysis in stage II (pT3/4pN0) disease (n=271) revealed that the addition of FA tended to reduce the 5-year local recurrence (LR) rate by 55% and increase recurrence-free survival and OS rates by 12 and 13%, respectively, relative to 5-FU alone. CONCLUSIONS: Interferon-α cannot be recommended for adjuvant chemoradiotherapy of rectal cancer. In UICC stage II disease, the addition of FA tended to lower LR and increased survival. The addition of FA to 5-FU may be an effective option for adjuvant chemoradiotherapy of UICC stage II rectal cancer.

C-11 methionine positron emission tomography/computed tomography localizes parathyroid adenomas in primary hyperparathyroidism.

In patients with primary hyperparathyroidism (pHPT), positive preoperative localization studies enable to perform a minimally invasive approach for parathyroid surgery. However, current imaging techniques are not always successful. We therefore conducted a study to determine the sensitivity of C-11 methionine positron emission tomography/computed tomography (Met-PET/CT) in localizing parathyroid adenomas in pHPT. Met-PET/CT scans of the neck and mediastinum of 33 patients undergoing parathyroidectomy for primary HPT were compared with intraoperative and histological findings. Primary HPT was caused by a single gland adenoma in 30 patients, while another 3 patients had multiglandular disease. Met-PET/CT scan correctly located a single gland adenoma in 25 out of 30 (83%) patients with pHPT, among them 2 patients with persistent disease, 7 patients with prior neck surgery, and 8 patients with concomitant thyroid nodules. In 3 patients with multiglandular disease, Met-PET/CT showed only one enlarged parathyroid gland in two individuals and was negative in the third patient. Statistical analysis found a significant correlation between true-positive results and the weight (2.42+/-4.05 g) and diameter (2.0+/-1.18 cm) of parathyroid adenomas while the subgroup with false negative findings had significantly smaller (0.98+/-0.54 cm) and lighter (0.5+/-0.38 g) glands. Sensitivity was 83% for single gland adenomas and 67% for multiglandular disease. Met-PET/CT correctly localized 83% of single gland parathyroid adenomas in patients with pHPT. However, preoperative localization of multiglandular disease due to double adenomas or parathyroid hyperplasia remained difficult.

Difficult diagnosis of a large cystic retroperitoneal tumor mimicking a hepatic origin.

Schwannomas are rare tumors, usually benign, originating from the nerve sheath, and found only infrequently in the retroperitoneal space. We report on a 67-year-old woman who was initially misdiagnosed and treated for a liver hydatid cyst. After incomplete resection and recurrence of the tumor, we were able to diagnose a large retroperitoneal schwannoma that completely displaced the liver to the left abdomen. The patient underwent surgical resection of the schwannoma; pathological evaluation revealed a cystic tumor measuring 18.5 × 18 × 12.5 cm, with tumor cells staining strongly positive for S-100. Retroperitoneal schwannomas may mimic cystic hepatic tumors and should, therefore, be considered as a differential diagnosis in such cases. We describe the diagnostic modalities and difficulties in the approach of a cystic liver tumor.

Anti-apoptotic and growth-stimulatory functions of CK1 delta and epsilon in ductal adenocarcinoma of the pancreas are inhibited by IC261 in vitro and in vivo.

BACKGROUND: Pancreatic ductal adenocarcinomas (PDACs) are highly resistant to treatment due to changes in various signalling pathways. CK1 isoforms play important regulatory roles in these pathways. AIMS: We analysed the expression levels of CK1 delta and epsilon (CK1delta/in) in pancreatic tumour cells in order to validate the effects of CK1 inhibition by 3-[2,4,6-(trimethoxyphenyl)methylidenyl]-indolin-2-one (IC261) on their proliferation and sensitivity to anti-CD95 and gemcitabine. METHODS: CK1delta/in expression levels were investigated by using western blotting and immunohistochemistry. Cell death was analysed by FACS analysis. Gene expression was assessed by real-time PCR and western blotting. The putative anti-tumoral effects of IC261 were tested in vivo in a subcutaneous mouse xenotransplantation model for pancreatic cancer. RESULTS: We found that CK1delta/in are highly expressed in pancreatic tumour cell lines and in higher graded PDACs. Inhibition of CK1delta/in by IC261 reduced pancreatic tumour cell growth in vitro and in vivo. Moreover, IC261 decreased the expression levels of several anti-apoptotic proteins and sensitised cells to CD95-mediated apoptosis. However, IC261 did not enhance gemcitabine-mediated cell death either in vitro or in vivo. CONCLUSIONS: Targeting CK1 isoforms by IC261 influences both pancreatic tumour cell growth and apoptosis sensitivity in vitro and the growth of induced tumours in vivo, thus providing a promising new strategy for the treatment of pancreatic tumours.

The stem cell-associated Hiwi gene in human adenocarcinoma of the pancreas: expression and risk of tumour-related death.

Piwi proteins and their interaction with piRNAs have rapidly emerged as important contributors to gene regulation, indicating their crucial function in germline and stem cell development. However, data on the Hiwi 1 (Hiwi) gene, one of the four human Piwi homologues, are still scarce. Therefore, we investigated the Hiwi mRNA expression in microdissected PDAC tissues from patients with ductal adenocarcinoma of the pancreas (PDAC) by quantitative real-time PCR and the protein expression by immunohistochemistry. Elevated levels of Hiwi mRNA transcripts were measured in 40 out of 56 tissues and a positive immunostaining of Hiwi was detected in tumours of 21 out of 78 patients. There was no general impact of elevated Hiwi mRNA transcript levels or protein expression on survival, as tested by multivariate Cox regression and Kaplan-Meier analysis. However, men showed a significantly increased risk for tumour-related death in case of down- or upregulated expression of Hiwi mRNA (relative risk (RR)=2.78; P=0.034). In summary, we report the first analysis of Hiwi expression in PDAC and its impact on prognosis. We suggest that alterations in mRNA expression of Hiwi can increase the risk of tumour-related death in male PDAC patients.

Anorectal amelanotic melanoma.

OBJECTIVE: Anorectal melanoma is a rare, highly malignant tumour with a poor 5 year survival of 10%. Most anorectal melanomas have gross and/or histologic pigmentation, however about 30% of anorectal melanomas are amelanotic. METHOD: We report three cases of amelanotic anorectal melanomas and integrate our data with six case reports of amelanotic malignant melanoma from the literature. Further we compare clinicopathological data and clinical outcome with large series of anorectal melanomas (both, amelanotic and pigmentated). RESULTS: There were seven females and two males, of median age 62 years (range: 45-75 years). Rectal bleeding was the leading symptom in all cases with a mean duration of 4 months before diagnosis. Eight of nine patients developed distant metastases. Median survival was 14 months (range: 3-60 months). A tumour thickness of < 4 mm was correlated with long-term disease-free survival, whereas tumour thickness of 4 mm or more was correlated with systemic recurrence. CONCLUSION: Early diagnosis is key for efficient treatment and improved survival rate for patients with this unusual variant of melanoma. There is no difference in terms of age, time of diagnosis, stage and survival between pigmented and amelanotic anorectal melanoma.

[Rare cause of recurring necrotising pancreatitis]. / Seltene Ursache einer rezidivierenden, nekrotisierenden Pankreatitis.

BACKGROUND: Necrotising pancreatitis may develop as a consequence of pancreatic duct obstruction by stones, tumors or in the presence of a pancreas divisum. Alcohol and nicotine are regarded as risk factors for the disease becoming chronic. PATIENT AND COURSE OF THE DISEASE: A 63-year-old female patient with suspected cystadenocarcinoma of the pancreas tail, which was resolved as a pancreatic pseudocyst, was treated for recurrent pancreatitis for 2 years. A tumor in the pancreas head was only detected on a follow-up CT after resection of a complicating liver abscess. In retrospect, progressive pancreatic duct anomalies were visible on previous scans. Partial duodenopancreatectomy confirmed the presence of a pancreas head carcinoma. CONCLUSION: Continuous critical re-evaluation of all potential causes of pancreatitis including rare conditions, such as a tumor, is required particularly if pancreatitis recurs over a long period. Re-evaluation of studies over time and of findings apart from the actual main focus of the complication, in this case pancreatitis of the pancreas tail, may help to detect the underlying disease instead of just treating the consequences.

Everolimus and mycophenolate mofetil sensitize human pancreatic cancer cells to gemcitabine in vitro: a novel adjunct to standard chemotherapy?

BACKGROUND/AIMS: Gemcitabine improves survival in pancreatic adenocarcinoma. A variety of drugs have been tested to potentiate gemcitabine treatment for pancreatic cancer cells. Two major immunosuppressive drugs, mycophenolate mofetil (MMF) and everolimus (RAD001) have been shown to exert an anti-tumoral effect, but their ability to sensitize human pancreatic cell lines during gemcitabine treatment remains unclear. We examined the effects of everolimus and MMF on gemcitabine-treated MiaPaCa and Panc-1 cell lines. METHODS: MiaPaCa and Panc-1 human pancreatic tumor cell lines were subjected to everolimus (0.001-1 microg/ml) or MMF (0.1-100 microg/ml) treatment in combination with gemcitabine (1-10(6) nM). Western blot analysis was performed for Panc-1 cells in the presence or absence of TGF-beta1 and different treatments: 0.1-100 muicro/ml MMF and 0.1-100 microg/ml everolimus. The antiproliferative effect of the treatment was assessed by BrdU test. The results were evaluated by two-way analysis of variance followed by post-hoc tests, and nonlinear regression analysis for dose-response rates. RESULTS: As expected, standard treatment doses of gemcitabine decreased proliferation dose-dependently. Everolimus increased the actual EC(50) response to gemcitabine treatment (1-10(3) nM) to as much as 83.1 and 82.1% in MiaPaCa and Panc-1 cell lines, respectively. Likewise, concomitant administration with MMF altered the EC(50) of gemcitabine treatment in MiaPaCa cell lines to values between 76.8 and 85.2% for doses of >or=1 microg/ml. Even the minor dose of MMF (0.1 microg/ml) increased the antiproliferative effect of gemcitabine by 43.5% for MiaPaCa and 42.4% for Panc-1 cells. In addition, treatment of Panc-1 cells with MMF (0.1-100 microg/ml) dose-dependently inhibited TGF-beta1-induced collagen expression. CONCLUSION: We found an overadditive antiproliferative effect of both MMF and everolimus in gemcitabine-treated MiaPaCa and Panc-1 cells in vitro, and an additional inhibitory effect of MMF on TGF-beta1-induced collagen type I expression. Interestingly, both the sensitizing effect of pancreatic cancer cells to gemcitabine treatment and the inhibition of collagen type I expression could be achieved by clinically feasible doses of everolimus and MMF. The use of these drugs is promising as a novel adjunct to standard chemotherapy.

Treatment of Barrett's esophagus with argon plasma coagulation and antireflux surgery. A retrospective analysis.

BACKGROUND/AIMS: The aim of this study was to assess the efficacy and the results of ablation of Barrett'esophagus by endoscopic argon plasma coagulation (APC) followed by fundoplication. METHODOLOGY: Between January 1999 and December 2004, 21 patients with histological proven, short BE and scheduled for fundoplication, were treated by APC. Treatment was repeated until histological confirmation of complete ablation was obtained. All patients underwent surgical correction of reflux by Nissen fundoplication. Response to treatment was assessed at follow up with endoscopy every 6 to 12 months. RESULTS: BE ablation was obtained in all patients after a mean of 3.6 APC sessions. There was no mortality and morbidity was 19% (4/21 patients). All patients underwent 360 degrees Nissen fundoplication as antireflux procedure. There was no operative mortality and no major complications requiring re-operation. Mean postoperative hospital stay was 7.9 days. Postoperatively 17/21 patients had at least one endoscopic control. The mean observation time was 17.5 months. Recurrence of Barrett epithelium was observed in 6 patients at a mean of 9.6 months after fundoplication. CONCLUSIONS: Our results show that the combination of APC and fundoplication is a safe and effective treatment option for most patients with uncomplicated BE. Although no cancer development was observed, larger studies with a longer follow up are required to assess the impact of APC on cancer risk.

Antiproliferative and overadditive effects of everolimus and mycophenolate mofetil in pancreas and lung cancer cells in vitro.

BACKGROUND: Everolimus inhibits the growth of several tumor cell lines in vitro as well as tumor growth in a rat model. Mycophenolate mofetil (MMF) inhibits growth of a Walker sarcoma in a rat model in vivo. Herein we tested the in vitro antiproliferative capacity of everolimus and MMF on a pancreatic tumor cell line Panc-1 and on a small cell lung cancer cell line ScLc. MATERIALS AND METHODS: Cells were cultured under standardized conditions. Everolimus was added in increasing doses from 0.005 to 500 microg/mL; MMF was used from 0.05 to 5000 microg/mL. For co-incubation experiments, we combined everolimus (0.005 microg/mL and 0.05 microg/mL) with five concentrations of MMF; and MMF (0.5 microg/mL and 5 microg/mL) with five concentrations of everolimus. The antiproliferative capacity was assessed by a BrdU incorporation assay. RESULTS: Everolimus and MMF inhibited BrdU incorporation into Panc-1 and ScLc in a dose-dependent fashion. A 50% inhibition was seen in Panc-1 only at 50 microg/mL everolimus, but in ScLc at 5 microg/mL everolimus. MMF was clearly more potent in Panc-1: 50% inhibition was observed at 5 microg/L. In ScLc, 40% inhibition of BrdU incorporation was seen only at 50 microg/L MMF. In co-incubation, an effective combination for both Panc-1 and ScLc was 5 microg/mL MMF with 0.005 microg/mL everolimus resulting in 50% inhibition of BrdU incorporation (P < .001). CONCLUSIONS: Everolimus and MMF showed dose-dependent antiproliferative effects in tumor cell lines in vitro both alone and in combination. The combined use of everolimus and MMF showed supra-additive effects at concentrations used for therapeutic immunosuppression in patients.

Human pancreatic adenocarcinomas express Fas and Fas ligand yet are resistant to Fas-mediated apoptosis.

The Fas system, comprising the Fas receptor (Fas, CD95, APO-1) and its ligand, Fas ligand (FasL), is a central mediator of programmed cell death in various physiological and pathological processes. Recent evidence indicated that tumor cells can exploit this system to their benefit in the dialogue with the host immune system. We have shown that all human pancreatic adenocarcinoma cell lines tested by fluorescence-activated cell sorting analysis (6 of 6) and immunocytochemistry (12 of 12) were positive for Fas expression, as were normal and malignant duct cells in pancreatic tissue sections. However, despite Fas expression, pancreatic tumor cells have become largely resistant toward recombinant FasL- or anti-APO-1 agonistic antibody-induced apoptosis. This resistance correlated with high levels in pancreatic tumor cells of mRNA for FAP-1, a Fas-associated phosphatase that can block the apoptotic function of Fas. Using a variety of methodological approaches, we also present evidence for the production of FasL by pancreatic tumor cells because 6 of 6 pancreatic tumor cell lines were found to contain FasL mRNA as well as the Mr 40,000 and Mr 26,000 forms of the FasL protein. Likewise, pancreatic tissue revealed FasL-specific immunostaining in pancreatic tumor cells but not in the surrounding stroma. In coculture experiments, pancreatic tumor cells displayed a cytotoxic effect toward the Fas-sensitive Jurkat T-cell line, which could be inhibited by a FasL-specific neutralizing antibody. Together, these results support the recently proposed "counterattack model" for local deletion of tumor-reactive T-cells by tumor cell-derived FasL.