Biomedical subjects

Peter Nygren

Publications and source records attributed to Peter Nygren.

At least 19 recordsLinked to original sources

PubMed2007

STAT1 signaling is associated with acquired crossresistance to doxorubicin and radiation in myeloma cell lines.

The myeloma cell line RPMI 8226/S and its doxorubicin resistant subline 8226/Dox40 were used as models to explore the potential importance of the STAT1 signaling pathway in drug and radiation resistance. The 40-fold doxorubicin resistant subline 8226/Dox40 was found to be crossresistant to single doses of 4 and 8 Gy of radiation. A genome-wide mRNA expression study comparing the 8226/Dox40 cell line to its parental line was performed to identify the underlying molecular mechanisms. Seventeen of the top 50 overexpressed genes have previously been implicated in the STAT1 signaling pathway. STAT1 was over expressed both at the mRNA and protein level. Moreover, analyses of nuclear extracts showed higher abundance of phosphorylated STAT1 (Tyr 701) in the resistant subline. Preexposure of the crossresistant cells to the STAT1 inhibiting drug fludarabine reduced expression of overexpressed genes and enhanced the effects of both doxorubicin and radiation. These results show that resistance to doxorubicin and radiation is associated with increased STAT1 signaling and can be modulated by fludarabine. The data support further development of therapies combining fludarabine and radiation.

Antibiotics, Antineoplastic↗

PubMed2006

Pharmacological profiling of disulfiram using human tumor cell lines and human tumor cells from patients.

The thiocarbamate drug disulfiram has been used for decades in the treatment of alcohol abuse. Disulfiram induces apoptosis in a number of tumor cell lines and was recently by us proposed to act as a 26S proteasome inhibitor. In this work we characterized disulfiram in vitro with regard to tumor-type specificity, possible mechanisms of action and drug resistance and cell death in human tumor cell lines and in 78 samples of tumor cells from patients using the fluorometric microculture cytotoxicity assay and the automated fluorescence-imaging microscope ArrayScan((R)). Disulfiram induced cytotoxicity in a biphasic pattern in both cell lines and patient tumor cells. Disulfiram induced apoptosis as measured by cell membrane permeability, nuclear fragmentation/condensation and caspase-3/7 activation using high content screening assays. For many of the cell lines tested disulfiram was active in sub-micromolar concentrations. When comparing the logIC(50) patterns with other cytotoxic agents, disulfiram showed low correlation (R<0.5) with all drugs except lactacystin (R=0.69), a known proteasome inhibitor, indicating that the two substances may share mechanistic pathways. Disulfiram was more active in hematological than in solid tumor samples, but substantial activity was observed in carcinomas of the ovary and the breast and in non-small cell lung cancer. Disulfiram also displayed higher cytotoxic effect in cells from chronic lymphocytic leukemia than in normal lymphocytes (p<0.05), which may indicate some tumor selectivity. These results together with large clinical experience and relatively mild side effects encourage clinical studies of disulfiram as an anti-cancer agent.

Cell Line, Tumor↗

PubMed2006

Inhibition of proteasome activity, nuclear factor-KappaB translocation and cell survival by the antialcoholism drug disulfiram.

The proteasome pathway is an important target for anticancer drug development. Here, we identify the antialcoholism drug disulfiram and its analogue pyrrolidine dithiocarbamate (PDTC) as inhibitors of the 26S proteasome activity in a cell-based screening assay. As expected for proteasome inhibitors, these compounds also inhibited TNF-alpha-induced nuclear factor-KappaB (NF-KappaB) translocation and were cytotoxic. Disulfiram was more cytotoxic against chronic lymphocytic leukemia cells compared to peripheral blood mononuclear cells (PBMC) at clinically achievable concentrations. Proteasome and NF-KappaB inhibition were achieved with a potency in the same range as that of the clinically used proteasome inhibitor bortezomib. Disulfiram was also able to induce accumulation of p27(Kip1) and to prolong the half-life of c-Myc, both targets for proteasome-dependent degradation. It is concluded that the previously observed antitumoral and NF-KappaB inhibiting activity of disulfiram and PDTC could be attributed to their inhibition of the 26S proteasome.

Alcohol Deterrents↗

PubMed2006

Screening of an annotated compound library for drug activity in a resistant myeloma cell line.

PURPOSE: Resistance to anticancer drugs is a major problem in chemotherapy. In order to identify drugs with selective cytotoxic activity in drug-resistant cancer cells, the annotated compound library LOPAC1280, containing compounds from 56 pharmacological classes, was screened in the myeloma cell line RPMI 8226 and its doxorubicin-resistant subline 8226/Dox40. METHODS: Cell survival was measured by the Fluorometric Microculture Cytotoxicity Assay. RESULTS: Selective cytotoxic activity in 8226/Dox40 was obtained for 33 compounds, with the most pronounced difference observed for the glucocorticoids. A microarray analysis of the cells showed a difference in mRNA-expression for the glucocorticoid receptor suggesting potential mechanisms for the difference in glucocorticoid sensitivity. In the presence of the glucocorticoid-receptor antagonist RU486, the sensitivity to the glucocorticoids was reduced and a similar effect level in RPMI 8226 and 8226/Dox40 was achieved. CONCLUSION: In conclusion, screening of mechanistically annotated compounds on drug-resistant cancer cells can identify compounds with selective activity and provide a basis for the development of novel treatments of drug-resistant malignancies.

Antineoplastic Agents↗

PubMed2006

Accuracy of assessment of distress, anxiety, and depression by physicians and nurses in adolescents recently diagnosed with cancer.

BACKGROUND: As staff members prioritize medical resources for patients, it is imperative to find out whether their assessments of patients' health status agree with patients' assessments. The degree to which physicians and nurses can identify the distress, anxiety, and depression experienced by adolescents recently diagnosed with cancer was examined here. PROCEDURE: Adolescents undergoing chemotherapy (13-19 years, n = 53), physicians (n = 48), and nurses (n = 53) completed a structured telephone interview, 4-8 weeks after diagnosis or relapse, investigating disease and treatment-related distress, anxiety, and depression. RESULTS: The accuracy of staff ratings of physical distress could be considered acceptable. However, problems of a psychosocial nature, which were frequently overestimated, were difficult for staff to identify. Staff underestimated the distress caused by mucositis and worry about missing school more than they overestimated distress. These aspects were some of the most prevalent and overall worst according to the adolescents. Both physicians and nurses overestimated levels of anxiety and depression. Nurses tended to show higher sensitivity than physicians for distress related to psychosocial aspects of distress, while physicians tended to show higher accuracy than nurses for physical distress. CONCLUSIONS: Staff was reasonably accurate at identifying physical distress in adolescents recently diagnosed with cancer whereas psychosocial problems were generally poorly identified. Thus, the use of staff ratings as a "test" to guide specific support seems problematic. Considering that the accuracy of staff ratings outside a research study is probably lower, identification of and action taken on adolescent problems in relation to cancer diagnosis and treatment need to rely on direct communication.

Adolescent↗

PubMed2006

Telomerase activity is not a key determinant of sensitivity to standard cytotoxic drugs in human esophageal carcinoma cell lines.

The aim of the present study was to investigate if basal telomerase activity levels may predict sensitivity to cytotoxic drugs in a panel of human esophageal carcinoma cell lines. The TRAPeze telomerase detection assay was used to investigate telomerase activity in the cell lines. Cytotoxic drug sensitivity for 20 standard cytotoxic agents was assessed using the fluorometric microculture cytotoxicity assay (FMCA). Telomerase activity was detected in all cell lines with a broad range of activity levels. Drug sensitivity also varied considerably between the cell lines. Except for a P value towards a correlation between mitoxantrone and telomerase activity (P=0.054), no statistically significant correlation was found between telomerase activity levels and sensitivity to investigated drugs, including key drugs such as cisplatin (P=0.9), 5-fluorouracil (P=0.8) and doxorubicin (P=0.54). We therefore conclude that basal telomerase activity level is not a key determinant of sensitivity to standard cytotoxic drugs in esophageal carcinoma cell lines.

Antineoplastic Agents↗

PubMed2006

Phenotype-based screening of mechanistically annotated compounds in combination with gene expression and pathway analysis identifies candidate drug targets in a human squamous carcinoma cell model.

The squamous cell carcinoma HeLa cell line and an epithelial cell line hTERT-RPE with a nonmalignant phenotype were interrogated for HeLa cell selectivity in response to 1267 annotated compounds representing 56 pharmacological classes. Selective cytotoxic activity was observed for 14 of these compounds dominated by cyclic adenosine monophosphate (cAMP) selective phosphodiesterase (PDE) inhibitors, which tended to span a representation of the chemical descriptor space of the library. The PDE inhibitors induced delayed cell death with features compatible with classical apoptosis. The PDE inhibitors were largely inactive when tested against a cell line panel consisting of hematological and nonsquamous epithelial phenotypes. In a genome-wide DNA microarray analysis, PDE3A and PDE2A were found to be significantly increased in HeLa cells compared to the other cell lines. The pathway analysis software PathwayAssist was subsequently used to extract a list of proteins and small molecules retrieved from Medline abstracts associated with the hit compounds. The resulting list consisted of major parts of the cAMP-protein kinase A pathway linking to ERK, P38, and AKT. This molecular network may provide a basis for further exploitation of novel candidate targets for the treatment of squamous cell carcinoma.

Carcinoma, Squamous Cell↗

PubMed2005

Lack of effect of aprepitant on the pharmacokinetics of docetaxel in cancer patients.

BACKGROUND: Aprepitant is a selective neurokinin-1 receptor antagonist that is effective for the prevention of nausea and vomiting caused by highly emetogenic chemotherapy. In vitro, aprepitant is a moderate inhibitor of the CYP3A4 enzyme, which is involved in the clearance of several chemotherapeutic agents. In this study we examined the potential for aprepitant to affect the pharmacokinetics and toxicity of intravenously administered docetaxel, a chemotherapeutic agent that is primarily metabolized by CYP3A4. METHODS: A total of 11 cancer patients (4 male, 7 female, aged 50-68 years) were enrolled in this multicenter, randomized, open-label, two-period, crossover study. Patients received a single infusion of docetaxel monotherapy, 60-100 mg/m(2), on two occasions at least 3 weeks apart. During one of the cycles (treatment A), patients received docetaxel alone. During the alternate cycle (treatment B), they also received aprepitant 125 mg orally 1 h prior to docetaxel infusion (day 1), and a single oral dose of aprepitant 80 mg on days 2 and 3. The pharmacokinetic profile of docetaxel was assessed over 30 h following docetaxel infusion. Blood counts were monitored on days 1, 4, 7, and 14. RESULTS: Ten patients completed the study. Concomitant administration of aprepitant did not cause any statistically or clinically significant changes in docetaxel pharmacokinetics. Values for docetaxel alone (treatment A) versus docetaxel with aprepitant (treatment B) were as follows: geometric mean AUC(0-last) was 3.26 vs 3.17 microg h/ml (P>0.25; ratio B/A 0.97); geometric mean AUC(0-infinity) 3.51 vs 3.39 microg h/ml (P>0.25; ratio B/A 0.96); geometric mean C(max) was 3.53 vs 3.37 microg/ml (P>0.25; ratio B/A 0.95); and geometric mean plasma clearance was 23.3 vs 24.2 l/h/m(2) (P>0.25; ratio B/A 1.04). The corresponding harmonic mean half-life values were 10.1 and 8.5 h. The two treatment regimens had similar tolerability profiles; the median absolute neutrophil count nadirs were 681/mm(3) during treatment with docetaxel alone and 975/mm(3) during aprepitant coadministration. CONCLUSIONS: Aprepitant had no clinically significant effect on either the pharmacokinetics or toxicity of standard doses of docetaxel in cancer patients. Aprepitant at clinically recommended doses may have a low potential to affect the pharmacokinetics of intravenous chemotherapeutic agents metabolized by CYP3A4.

Administration, Oral↗

PubMed2005

Impact of fish oil and melatonin on cachexia in patients with advanced gastrointestinal cancer: a randomized pilot study.

OBJECTIVE: The effect of fish oil (FO), melatonin (MLT), or their combination and dietary advice on cachexia and biochemistry variables reflecting cachexia were investigated in patients with advanced gastrointestinal cancer. METHODS: Twenty-four patients not amenable to standard anticancer treatment and with documented weight loss and/or decreased serum albumin were included. They were randomized to 30 mL/d of FO, which provided 4.9 g of eicosapentaenoic acid and 3.2 g of docosahexanoic acid, or 18 mg/d of MLT for 4 wk. During the next 4 wk, all patients had FO and MLT. Serum or plasma was analyzed for tumor necrosis factor-alpha, interleukin-1beta, soluble interleukin-2 receptor, interleukin-6, and interleukin-8 and the fatty acids eicosapentaenoic acid, docosahexanoic acid, arachidonic acid, and linoleic acid. RESULTS: Serum levels of eicosapentaenoic acid and docosahexanoic acid increased as expected with FO. No major changes in biochemical variables and cytokines were observed with any intervention. In the FO group, 5 of 13 patients (38%) showed weight stabilization or gain compared with 3 of 11 patients (27%) in the MLT group. After combining interventions, approximately 63% of patients showed such responses. CONCLUSIONS: FO, MLT, or their combination did not induce major biochemical changes indicative of a strong anticachectic effect. Nonetheless, the interventions used may have produced a weight-stabilizing effect.

Aged↗

PubMed2005

Targeted drugs in metastatic colorectal cancer with special emphasis on guidelines for the use of bevacizumab and cetuximab: an Acta Oncologica expert report.

From having been a 'single-drug not very interesting cancer type' from a medical treatment perspective, treatment of colorectal cancer (CRC) has during the past five years become a more complex issue of the appropriate use of several cytotoxic drugs sometimes integrated with advanced metastatic surgery with curative intent. The new drugs have provided significant benefit to the patients, so far mostly in the metastatic setting but also in adjuvant treatment. The significant progress in molecular and tumour biology has produced a great number of new 'targeted' drugs that are now in various stages of clinical development. Two of these drugs, the monoclonal antibodies bevacizumab (Avastin) and cetuximab (Erbitux), directed against VEGF and EGFR, respectively, have recently been approved within the EU for use in metastatic CRC. This Nordic Expert Consensus Report summarizes the current status of chemotherapy in metastatic CRC, overviews the clinical status of targeted drugs in CRC and, finally, provides guidelines for the routine clinical use of bevacizumab and cetuximab based on the most recently available clinical data.

Antibodies, Monoclonal↗

PubMed2005

In vitro drug resistance in B cell chronic lymphocytic leukemia: a comparison with acute myelocytic and acute lymphocytic leukemia.

The aim of the study was to evaluate cellular drug resistance in B cell chronic lymphocytic leukemia (B-CLL) in vitro, and compare it with that in acute myelocytic leukemia (AML) and acute lymphocytic leukemia (ALL). In vitro drug resistance was analyzed by the fluorometric microculture cytotoxicity assay (FMCA) in all samples from patients with leukemia sent to our laboratory between 1992 and 2001. Up to 14 standard drugs were evaluated in samples from 66 patients with B-CLL, 212 patients with AML and 80 patients with ALL. B-CLL cells were found to be more sensitive than cells from both AML and ALL to cytarabine, cladribine, fludarabine, doxorubicin, idarubicin, vincristine and cyclophosphamide (p<0.05). No difference in cellular drug resistance was found between B-CLL and ALL cells for prednisolone, whereas AML cells were more resistant (p<0.0001). In B-CLL, cells from patients who had received previous chemotherapy were more resistant to almost all tested drugs as compared to cells from treatment-naive patients. In AML and ALL, in vitro drug resistance was not related to previous chemotherapy. For all drugs, there was a good agreement between the activity in vitro and the known clinical disease-specific activity. The study also demonstrated an acquired cellular drug resistance in B-CLL, but not in the acute leukemias.

Adolescent↗

PubMed2005

Predictive value of in vitro assessment of cytotoxic drug activity in advanced breast cancer.

The predictive value of a short-term in vitro total cell kill assay was investigated in 37 patients with breast cancer (BC). Tumor cells were prepared from tumor samples from 17 patients with locally advanced and 20 with metastatic BC, which were treated with the FEC (5-fluorouracil, epirubicin, cyclophosphamide) regimen or a combination of epirubicin and taxane. The cells were then tested in the fluorometric microculture cytotoxicity assay (FMCA), which is based on the conversion by viable cells of fluorescein diacetate to fluorescent fluorescein, for sensitivity to the drugs given in vivo. The FMCA data were scored as low, intermediate or extreme drug resistance based on the median cell survival +/- SD for each drug and patient subset. The drug classification for each sample was then correlated to clinical outcome in terms of objective response and time to tumor progression. The FMCA significantly predicted objective tumor response with a sensitivity of 89% and a specificity of 53%. Furthermore, in patients with locally advanced BC, low drug resistance was significantly associated with longer time to progression. It is concluded that the FMCA seems to report clinically relevant cytotoxic drug sensitivity data in BC. The potential clinical role of the FMCA and similar tests is discussed.

Antineoplastic Agents↗

PubMed2004

Translocation t(12;21) is related to in vitro cellular drug sensitivity to doxorubicin and etoposide in childhood acute lymphoblastic leukemia.

The t(12;21) (p13;q22) translocation resulting in ETV6/RUNX1 (previously named TEL/AML1) gene fusion is present in about 25% of children with precursor B-lineage acute lymphoblastic leukemia (B-ALL). We successfully tested 275 precursor B-ALL samples from children aged 1 to 17 years to determine the relation between t(12;21) and in vitro cellular drug resistance, measured by the fluorometric microculture cytotoxicity assay (FMCA). Samples from 83 patients (30%) were positive for t(12;21). The ETV6/RUNX1(+) samples were significantly more sensitive than ETV6/RUNX1(-) samples to doxorubicin, etoposide, amsacrine, and dexamethasone, whereas the opposite was true for cytarabine. After matching for unevenly distributed patient characteristics, that is, excluding patients with high hyperdiploidy (> 51 chromosomes), t(9; 22), t(1;19), or 11q23 rearrangement, the ETV6/RUNX1(+) samples remained significantly more sensitive to doxorubicin (P = .001) and etoposide (P = .001). For the other drugs tested (amsacrine, cytarabine, dexamethasone, prednisolone, vincristine, 6-thioguanine, and 4-hydroperoxy-cyclophosphamide), no significant difference in cellular drug sensitivity was found. In conclusion, we found that the presence of the t(12;21) translocation in childhood precursor B-ALL is associated with a high tumor cell sensitivity to doxorubicin and etoposide. High throughput techniques should now be used to elucidate the cellular mechanisms by which ETV6/RUNX1 gene fusion is linked to increased sensitivity to these drugs.

Adolescent↗

PubMed2004

Modelling and simulation in the development and use of anti-cancer agents: an underused tool?

To help identify the role of modelling and simulation in the development of anti-cancer agents, their main advantages and the obstacles to their rational use, an expert meeting was organized by COST B15. This manuscript presents a synthesis of views expressed at that meeting and indicates future directions. The manuscript also shows some examples where modelling and simulation have proven to be of relevant value in the drug development process for anti-cancer agents.

Antineoplastic Agents↗

PubMed2004

Antitumor efficacy and acute toxicity of the novel dipeptide melphalanyl-p-L-fluorophenylalanine ethyl ester (J1) in vivo.

The novel alkylating dipeptide melphalanyl-p-L-fluorophenylalanine ethyl ester (J1) was evaluated for acute toxicity and antitumor activity in mice, with melphalan as a reference. To determine a safe and tolerable dose for efficacy studies the acute toxicity following intravenous injection in the tail vein was monitored using a 14-day schedule with up to four doses. The highest tested dose, 25 micromoles/kg, was considered close to this level, with minor effects on body weight gain but significant effects on hematological parameters. Melphalan and J1 appeared equitoxic with no statistically significant differences. Subsequently a mouse hollow fiber model was employed with subcutaneous implantation of fibers containing human tumor cells. Three different human tumor cell lines as well as two samples of primary human tumor cells (ovarian carcinoma and chronic lymphatic leukemia) were used as tumor models. At the dose level tested there was a marked and statistically significant decrease in both T-cell leukemia CCRF-CEM and small cell lung cancer NCI-H69 tumor cell growth and viability in response to J1 as compared with both placebo and melphalan treated groups. In primary ovarian carcinoma cells only J1 treatment resulted in significant tumor regression (net cell kill). In summary the results indicate that, despite an expected short half time in the blood circulation, the promising in vitro data from the previous studies of J1 seems translatable into the in vivo situation. At equal doses of alkylating units J1, compared to melphalan, was more active in the mouse hollow-fiber model, but showed similar general toxicity.

Animals↗

PubMed2004

Development and characterization of two human tumor sublines expressing high-grade resistance to the cyanoguanidine CHS 828.

The cyanoguanidine CHS 828 has shown promising antitumor properties and is currently in early clinical trials, although the mechanism of action still is largely unknown. In this study, resistant sublines of the histiocytic lymphoma cell line U-937 GTB and the myeloma line RPMI 8226 were developed by culturing under gradually increasing concentrations of CHS 828 until reaching 25 times the parental line EC50s. The new phenotypes demonstrate more than 400-fold resistance to CHS 828 and cross-resistance to six cyanoguanidine analogs, but no resistance to nine standard drugs of different mechanistic classes or to the cytotoxic guanidines m-iodobenzylguanidine and methylglyoxal-bis(guanylhydrazone). The resistant phenotypes were stable for several months even if cultivated in drug-free medium and no difference in proliferation, ultrastructural or morphologic appearance in the sublines could be detected. Neither was decreased accumulation of tritium-labeled CHS 828 observed. Furthermore, the new U-937 phenotype was not accompanied by changes in differentiation or an altered cell-cycle distribution. In the myeloma cell line, esterase activity was shown to be moderately enhanced. Two-dimensional protein electrophoresis was undertaken to unmask possible resistance-mediating proteins and/or the target molecule(s) for CHS 828. In the myeloma cell line, lambda light chain immunoglobulin (down-regulated) and a fatty acid-binding protein (up-regulated) were identified. The findings presented here indicate that development of specific cellular alterations is responsible for the gained CHS 828 resistance.

Antineoplastic Agents↗

PubMed2004

Cytotoxic effect in vivo and in vitro of CHS 828 on human myeloma cell lines.

CHS 828 is a pyridyl cyanoguanidine with promising antitumor activity both in vitro and in vivo, and has previously been found especially active against tumor cells obtained from patients with B cell chronic lymphocytic leukemia. In the present study the cytotoxic effect in vitro of CHS 828 was investigated on a panel of 10 human myeloma cell lines using the fluorometric microculture cytotoxicity assay. CHS 828 induced a concentration-dependent, but variable decrease in tumor cell survival in the cell line panel with inhibitory concentrations 50% (IC50) in the range 0.01-0.3 microM. These concentrations are below those achievable in vivo. There was no detectable dependence on P-glycoprotein-mediated or GSH-associated drug resistance and the drug showed low to moderate cross-resistance with standard drugs, including melphalan, vincristine and doxorubicin. Furthermore, sensitivity to CHS 828 showed no apparent relationship to growth factor dependence, tumor progression or phenotypic variability. CHS 828 was also tested in vivo using a hollow fiber model in rats with three of the cell lines. The results indicate a high cytotoxic activity of CHS 828. Overall, the results show a high cytotoxic activity of CHS 828 in the myeloma models, which might warrant its further development against myeloma.

Animals↗

PubMed2004

VH gene mutation status and cellular drug resistance in chronic lymphocytic leukaemia.

OBJECTIVE: B-cell chronic lymphocytic leukaemia (B-CLL) can be divided into two clinical entities based on the immunoglobulin variable heavy chain (VH) gene mutation status, as cases with unmutated VH genes display a more aggressive disease with shorter survival time than mutated cases. The aim of this study was to investigate whether differences in cellular drug resistance could give an explanation for these divergent clinical courses. METHODS: The VH gene mutation status was analysed in patients with previously untreated B-CLL using VH gene family-specific PCR amplification and nucleotide sequencing. In vitro sensitivity to cytarabine, fludarabine, cladribine, doxorubicin, idarubicin, vincristine, cyclophosphamide, melphalan and prednisolone was assessed using the non-clonogenic in vitro assay, fluorometric microculture cytotoxicity assay. RESULTS: The VH genes and in vitro drug resistance were successfully analysed in 46 cases, revealing that 25 (54%) cases showed unmutated and 21 (46%) cases mutated VH genes. Interestingly, the unmutated group generally tended to be more chemosensitive than the mutated group with significant differences for cytarabine and prednisolone (P < or = 0.01). CONCLUSION: The propensity of inferior drug response in mutated B-CLL may reflect a more differentiated disease than in unmutated B-CLL. We conclude that the difference in prognosis between B-CLL cases with unmutated and mutated VH genes could not be explained by difference in cellular drug resistance.

Antineoplastic Agents↗