Biomedical subjects

U Butzer

Publications and source records attributed to U Butzer.

11 recordsLinked to original sources

PubMed2000

Thymidylate synthase quantitation and in vitro chemosensitivity testing predicts responses and survival of patients with isolated nonresectable liver tumors receiving hepatic arterial infusion chemotherapy.

BACKGROUND: Patients with isolated, nonresectable liver tumors may receive regional hepatic arterial infusion (HAI) chemotherapy with response rates of about 50%. The objective of this study was to investigate the value of thymidylate synthase (TS) determination in combination with in vitro chemosensitivity testing to predict the responses and survival of patients receiving HAI. METHODS: TS mRNA expression was quantitated using a reverse transcription-polymerase chain reaction technique with beta-actin as the internal standard. In vitro chemosensitivity testing was performed with tumor cell suspensions using the human tumor colony-forming assay (HTCA). RESULTS: An analysis of the test combination in 24 consecutive patients revealed that 77% (10 of 13) of the sensitive and 9% (1 of 11) of the resistant patients had complete or partial clinical responses. Sensitive patients were 8.5-fold more likely to respond (P = 0.0036) and displayed with 32 months (range, 5-75 months) a longer median survival than resistant patients with 17 months (range, 3-28 months, P = 0.003). Analysis of the Kaplan-Meier curves revealed that sensitive patients had a higher overall survival probability, as determined by the log rank test (P = 0.044). CONCLUSIONS: These results suggest that the clinical outcomes of patients receiving HAI therapy may be predictable with TS quantitation and HTCA. It is possible, therefore, that this combination may be used in the future to select patients with liver tumors who will benefit from HAI before the start of regional chemotherapy.

Adult↗

PubMed2000

Pre-clinical evaluation of the activity of gemcitabine as a basis for regional chemotherapy of pancreatic and colorectal cancer.

AIMS: To estimate the potential activity of gemcitabine for hepatic arterial infusion (HAI) chemotherapy in pancreatic and colorectal cancer. METHODS: The anti-proliferative effects of gemcitabine were determined in MIA PaCa-2 and PMH2/89 pancreatic and HT29 and NMG64/84 colon cancer cell lines and in fresh tumours from patients with liver metastases of colon, rectal and pancreatic cancer in vitro using the human tumour colony forming assay. RESULTS: Gemcitabine showed concentration and time-dependent cytotoxic effects in all tested cell lines. The IC(50)of gemcitabine in MIA PaCa-2, PMH2/89, HT29 and NMG64/84 cells at 2 h exposure time were >100, 18, 100 and 2.5 microg/ml, respectively, at 4 h 15, 1.2, 45 and 0.5 microg/ml, respectively, and at 24 h 0.2, 0.1, 1.8 and 0.1 microg/ml, respectively. All tumours displayed concentration dependent inhibition of colony formation after exposure to gemcitabine for 2 h. The IC(50)values of gemcitabine in six of the 10 metastases were </=100 microg/ml. CONCLUSIONS: Based on our results and theoretical considerations regarding hepatic arterial infusion therapy gemcitabine seems to be suitable for HAI therapy phase II studies. Moreover, patients with colorectal or pancreatic tumours that demonstrated in vivo sensitivity may benefit from regional chemotherapy with gemcitabine.

Aged↗

PubMed1999

Increased oxidative stress in the RAW 264.7 macrophage cell line is partially mediated via the S-nitrosothiol-induced inhibition of glutathione reductase.

We investigated whether endogenously or exogenously produced nitric oxide (NO) can inhibit cellular glutathione reductase (GR) via the formation of S-nitrosothiols to decrease cellular glutathione (GSH) and increase oxidative stress in RAW 264.7 cells. The specificity of this inhibition was demonstrated by addition of a NO-synthase inhibitor, and met- or oxyhemoglobin. Using isolated GR we found that only certain NO donors inhibit this enzyme via S-nitrosothiol. Furthermore, we found that cellular GSH decrease is paralleled by an increase of superoxide anion production. Our results show that the GR enzyme is a potential target of S-nitrosothiols to decrease cellular GSH levels and to induce oxidative stress in macrophages.

Animals↗

PubMed1998

Overexpression of endothelium-derived nitric oxide synthase isoform 3 in the vasculature of human pancreatic tumor biopsies.

Cellular nitric oxide (NO) synthesis determines whether NO has cytoprotective or cytotoxic effects at anatomic sites; thus it is important to identify potential NO synthase isoforms in tumor tissue and tumor cell lines which might be involved in tumor development or destruction. Incubation of human pancreatic adenocarcinoma cell lines (AsPc-1, BxPc-3, CaPan-2) with cytokines resulted in increased NO formation, indicating the existence of the NOS2 isoform. This was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR) and western blot analysis. Furthermore, we identified the presence of the endothelium-derived NOS isoform 3 by RT-PCR analysis and immunohistochemistry in normal and pancreatic tumor biopsies. NOS3 was markedly overexpressed in the vasculature of the tumor tissue. RT-PCR analysis of tumor biopsies identified NOS isoform 2 mRNA in 60% of cases, but western blot analysis or immunohistochemistry scored negative for this isoform. It is noteworthy that the NOS enzyme activity in pancreatic tumor cell lines and tumor biopsies was inhibited by EGTA by approximately 30% and 65%, respectively. Our results suggest that increased endothelium-derived NOS isoform 3 expression in pancreatic adenocarcinomas regulates blood flow and is therefore involved in the vascularization and neovascularization of human pancreatic tumors.

Adenocarcinoma↗

PubMed1997

Thymidylate synthase is a predictor for response and resistance in hepatic artery infusion chemotherapy.

The value of intratumoral thymidylate synthase (TS) quantitation as a predictive parameter for hepatic artery infusion (HAI) chemotherapy in patients with colorectal liver metastases was investigated. Relative TS mRNA levels were determined in 29 tumor samples using a quantitative RT-PCR amplification method. The median level of expression was 3.0 x 10(-3) (no units) and varied considerably among the tumors over a range of 135-fold. Patients with low TS levels were 4.1-fold more likely to respond (P < 0.03) compared to patients with high TS levels. Our results indicate that TS quantitation is a valuable predictive marker for tumor response to HAI therapy.

Adult↗

PubMed1997

pH-dependent changes of nitric oxide, peroxynitrite, and reactive oxygen species in hepatocellular damage.

Low arterial blood pH and sustained nitric oxide (NO) production are critical parameters in inflammatory events such as sepsis, and appropriate treatment is still under debate. Because the stability of nitrogen and oxygen intermediates is dependent on the surrounding pH, we investigated whether the relationship among NO, peroxynitrite (ONOO-), and reactive oxygen species production also depends on the pH value, particularly with respect to their effects on hepatocellular damage. Our studies demonstrate that the extracellular pH influences NO and hydroxyl radical (OH) production in hepatocytes. Acidification (pH 7.0) of the medium revealed a significant increase (P < 0.05) of OH-like radicals, enhanced hepatocellular damage, and a sharp drop in cellular glutathione (GSH) content compared with levels measured at physiological or alkaline pH conditions. Furthermore, inhibition of NO synthesis at all pH conditions resulted in decreased NO production and cellular GSH levels but a simultaneous increase of OH-like radicals and hepatocellular damage with a maximum seen at pH 7.0. Our results suggest that hepatocellular damage is in part regulated by the surrounding pH and that inhibition of NO synthesis at acidic conditions (e.g., in sepsis) leads to increased reactive oxygen-mediated cell injury.

Animals↗

PubMed1996

Intraperitoneal regional chemotherapy with mitroxantrone.

Pharmacokinetic considerations and tests with cell lines and individual cell suspensions from metastatic human solid tumor biopsies suggested testing the efficacy of mitoxantrone (NOV) in intraperitoneal regional chemotherapy (IPRC). Twenty-seven patients with intraperitoneal metastatic disease of various solid tumors received cyclic IPRC with NOV for treatment of malignant ascites (N = 16) or of peritoneal carcinomatosis (N = 11) at a NOV instillate concentration of 10 micrograms/ml. A total of 125 cycles (1-5 per patient) were applied. Response and toxicity were registered according to WHO criteria. The response rate (CR+PR) was 56 percent in malignant ascites, 45 percent in peritoneal carcinomatosis, and 52 percent overall. There were no systemic toxicities. Regional side effects were bacteriemia (4 of 125 cycles), pain (2 of 125 cycles), small bowel stricture (1 of 27 patients), and small bowel perforation (1 of 27 patients). From these results we can conclude that NOV appears to be effective in IPRC for malignant ascites and peritoneal carcinomatosis at tolerable toxicities.

Antineoplastic Agents↗

PubMed1996

In vitro pharmalogic rationale for intraperitoneal regional chemotherapy.

We performed basic in vitro studies on cell lines and individual tumor cell suspensions to support the concept of intraperitoneal regional chemotherapy, and to improve the rationale for drug selection in this regional chemotherapeutic method. We defined the concentration-response behavior and the dependence of drug cytotoxicity on time using the two human colorectal carcinoma cell lines HT29 and NMG 64/84. In addition, the drugs concentration-response behavior and cytotoxic potency for IPRC after a single drug exposure at 10 micrograms/ml (5-FU at 100 micrograms/ml) was preclinically defined with in vitro phase II studies using single cell suspensions of human solid tumor biopsies in the human tumor colony assay (HTCA). The drugs doxorubicin (ADM), cisplatin (CDDP), epidoxorubicin (EPI), 5-fluorouracy (5-FU), 5-fluorodeoxyuridine (5-FUDR), melphalan (LPAM), mitomycin C (MMC), and mitroxantrone were incubated at increasing concentrations up to 1000 micrograms/ml at 10, 30, 60, 360, and 1440 minutes with the cell lines. These drugs, as well as vindesine (VDS) and mafosfamide (MAF) were also tested in the HTCA at increasing concentrations. The HTCA response rates at 10 micrograms/ml (5-FU and MAF at 100 micrograms/ml) were used for in vitro phase II comparisons of potential drug clinical activities. All test drugs showed a time- and concentration-dependent cytotoxic activity against the cell lines. Based on the cytotoxicity test results with HT29 and NMG 64/84, specific times were recommended for clinical therapy with each drug. In the HTCA, the drugs showed different cytotoxic concentration responses. The concentration-response behavior of each drug varied in individual tumor biopsies of the same histology. Comparing the response rates at 1 microgram/ml (5-FU and MAF 10 micrograms/ml) and 10 micrograms/ml (5-FU and MAF 100 micrograms/ml), an overall increase of in vitro response by a factor of 2.1 +/- 0.7 (1.1-3.7) was noted. We were able to prove this principle qualification of various test drugs in our in vitro studies and to suggest the optimal exposure times for their use in intraperitoneal chemotherapy. Based on these results, NOV was successfully used in an IPRC clinical study.

Antineoplastic Agents↗

PubMed1996

Regional chemotherapy directed by individual chemosensitivity testing in vitro: a prospective decision-aiding trial.

A prospective decision-aiding trial was performed to select drugs for regional chemotherapy of various liver tumors (n = 36) by individual drug testing. The drugs were chosen for hepatic artery infusion according to the individual chemosensitivity of tumor biopsies in the human tumor colony-forming assay (HTCA). In vitro HTCA sensitivity correlated with complete response (CR) + partial response (PR) + no change (NC) 93% of the time and with CR + PR 55% of the time. The test sensitivity was 90%, and the specificity was 67% for CR + PR + NC versus progressive disease (PD), whereas the sensitivity and specificity were 89% and 28%, respectively, for CR + PR versus NC + PD. The overall predictive accuracy of the test was 86% for CR + PR + NC versus PD and 58% for CR + PR versus NC + PD. Overall, 83% of this heterogenous patient group with various tumors achieved CR + PR + NC and a 50% clinical response (CR + PR). In vitro-sensitive patients showed a significantly lower intrahepatic progression rate (7% PD) than in vitro-resistant patients (57%; P < 0.05). These results indicate that the HTCA could identify active drugs for individualized hepatic artery infusion, and patients may profit from the use of in vitro-sensitive drugs.

Adult↗

PubMedDate not supplied

In vitro concentration response studies and in vitro phase II tests as the experimental basis for regional chemotherapeutic protocols.

The theoretical pharmacologic benefit of regional vs. systemic chemotherapy is defined and the concentration response behavior of cytostatic drugs and their optimal exposure times are described with human cancer cell lines (HT29, NMG64/84) and fresh human tumor cell suspensions in the human tumor colony assay (HTCA). The theoretical pharmacological advantages are 5.8 to 6 for adriamycin (ADM), 8 for cisplatinum (CDDP), 6.3 for epidoxorubicin (EPI), 22 to 58 for 5-fluorouracil (5FU), 4.6 for mitomycin C (MMC), and 6.3 for mitoxantrone (NOV). The drugs differed in their cytotoxic potency in vitro and thus also potential efficacy for regional chemotherapy; however, all but 5-fluorodeoxyuridine (5FUDR) exerted cytotoxicity dependent on exposure time and concentration. On average, elevation of the test concentrations by 1 lg doubled responses in fresh human tumor cell suspensions. From these results and clinical considerations, optimal times were defined for the regional chemotherapy strategies of hepatic artery infusion, intraperitoneal instillation, and chemoembolisation as performed at our institution.

Antineoplastic Agents↗

PubMedDate not supplied

Oxaliplatin exerts potent in vitro cytotoxicity in colorectal and pancreatic cancer cell lines and liver metastases.

BACKGROUND: Oxaliplatin displays potent activity in advanced colorectal cancer. The aim of this study was to estimate the potential efficacy of oxaliplatin for hepatic arterial infusion (HAI) chemotherapy. MATERIALS AND METHODS: The anti-proliferative effects of oxaliplatin in human HT29 and NMG64/84 colon and COLO-357 MIA PaCa-2 and PMH2/89 pancreatic cancer cell lines and in fresh liver metastases from patients with colorectal and pancreatic cancer were investigated using the human tumor colony forming assay. RESULTS: Oxaliplatin significantly inhibited the colony formation in all cell lines in a concentration- and time-dependent manner. All liver tumors displayed a significant concentration-dependent inhibition of colony formation after exposure to oxaliplatin for 2 hours. The IC50 of oxaliplatin of 9 of the 10 tumors was < 10 micrograms/ml. CONCLUSION: Oxaliplatin is suitable for HAI therapy phase II studies. Due to the low IC50 values of most tumors we suggest that patients with colorectal or pancreatic liver metastases may benefit from HAI with oxaliplatin.

Aged↗