Elzbieta Izbicka - Academia.edu (original) (raw)

Papers by Elzbieta Izbicka

Lung Cancer, May 1, 2009

Conclusions: It seems to be supported by evidence that severe alterations in bronchial mucosa hap... more Conclusions: It seems to be supported by evidence that severe alterations in bronchial mucosa happen in advanced COPD and 25% of them become precancerous lesions and even 1.6% are positive for neoplasia. That corroborates many authors' hypothesis that lung cancer can be considered such as real complication of severe COPD and that inflammation is a decisive factor with the immune mechanism correlation.

Cancer Research, May 1, 2007

5586 MBP-426 is a novel oxaliplatin-encapsulated transferrin (Tf) -conjugated N-glutaryl phosphat... more 5586 MBP-426 is a novel oxaliplatin-encapsulated transferrin (Tf) -conjugated N-glutaryl phosphatidylethanolamine (NGPE)-liposome. MBP-426 demonstrated potent anticancer preclinical activity and has recently entered clinical trials. Direct drug binding to Tf receptor (TfR) was demonstrated in human cancer cells in vitro; the drug delivery is thought to be enhanced via uptake by TfR. This study investigated activity of MBP-426 alone and in combination with gemcitabine or erlotinib in the PANC-1 human pancreas tumor xenograft model. Significant endpoints included mean tumor growth inhibition or regression, weight loss, and agent toxicity. In groups treated with MBP-426 alone and in combination with gemcitabine we further evaluated expression of biomarkers (TfR, cleaved caspase-3, PARP, survivin, CD31, Hif1a in tumor tissue; VEGF, TNF-a, bFGF, IL-6, MMP-2 and MMP-9 in serum) by immunostaining and multiplexed immunoassays, respectively. In vivo treatment with gemcitabine (40 mg/kg) resulted in reversible weight loss and moderate tumor growth inhibition (TGI=25%); no weight loss or TGI was reported for 50 mg/kg erlotinib. MBP-426 alone was inactive but the group co-treated with 40 mg/kg gemcitabine and 4 mg/kg MBP-426 reported significant (p 20% inhibition, p=0.011) in the 4 mg/kg MBP-426 plus gemcitabine treatment group. TNF-a was significantly suppressed by gemcitabine (50% inhibition, p=0.007), the low dose of MBP-426 alone (35% inhibition, p=0.043) and in combination with gemcitabine (38% inhibition, p=0.027). Taken together, these results demonstrate additive combinatorial effects of MBP-426 with gemcitabine and erlotinib in pancreatic adenocarcinoma in vivo. Serum TNF-a and MMP-2 levels might be pursued as potential biomarkers of drug efficacy in clinical trials. Supported by Mebiopharm

The goal of personalized medicine is to enhance our understanding of the disease at the molecular... more The goal of personalized medicine is to enhance our understanding of the disease at the molecular level and optimize drug treatment to best meet the needs of an individual. In addition to genomic biomarkers for drug response, the mitochondrial genome (mtDNA) ...

PubMed, Oct 15, 2003

Purpose: To assess the feasibility of administering tipifarnib, an oral nonpeptidomimetic competi... more Purpose: To assess the feasibility of administering tipifarnib, an oral nonpeptidomimetic competitive inhibitor of farnesyltransferase, in combination with gemcitabine and recommend doses for disease-directed clinical trials. The study also sought to identify drug-drug pharmacokinetic interactions, evaluate effects on protein farnesylation, and seek preliminary evidence for clinical activity. Experimental design: Patients with advanced solid malignancies were treated with tipifarnib at doses of 100, 200, and 300 mg twice daily continuously and 1000 mg/m(2) gemcitabine i.v. on days 1, 8, and 15 every 4 weeks. To identify pharmacokinetic interactions, the treatment and plasma sampling schemes were designed to permit comparisons of the pharmacokinetic behavior of each agent administered alone and together. The proportions of unfarnesylated and farnesylated HDJ2, a chaperone protein that undergoes farnesylation, were measured in peripheral blood mononuclear cells. Results: Nineteen evaluable patients were treated with 74 courses of tipifarnib/gemcitabine (mg/mg/m(2)). Myelosuppression was the principal toxicity. Dose-limiting myelosuppression occurred in 2 of 5 patients at the 300/1000 dose level, whereas 2 of 11 evaluable patients at the 200/1000 dose level experienced dose-limiting toxicity. There was no evidence of clinically relevant pharmacokinetic interactions between tipifarnib and gemcitabine. Inhibition of farnesylation of HDJ2, a potential surrogate for Ras and/or other potentially relevant farnesylated proteins, was demonstrated in peripheral blood mononuclear cells at all dose levels. Partial responses were noted in patients with advanced pancreatic and nasopharyngeal carcinomas. Conclusions: On the basis of the results of this study, the tipifarnib/gemcitabine dose level of 200/1000 is recommended for disease-directed studies. At this dose level, biologically relevant plasma concentrations of tipifarnib that consistently inhibit protein farnesylation in vitro are achieved and drug-induced inhibition of protein farnesylation is measured in most patients.

Clinical Cancer Research, Oct 1, 2007

A9 The goal of personalized medicine is to deliver the best treatment to the patient. In clinical... more A9 The goal of personalized medicine is to deliver the best treatment to the patient. In clinical oncology, proteomics can evaluate differential expression and post-translational modifications of proteins in healthy and diseased states. Given that many novel anticancer therapies are designed to target tumor proteins, proteomic analysis of tumor tissue should complement conventional genomic or immunohistochemical (IHC) analyses in delivering information relevant for diagnosis, prognosis and predicting tumor response to treatment. Formalin fixation and paraffin embedding (FFPE) of diagnostic specimens is the preparation method of choice for pathological assessment. We undertook this study to identify differentially expressed proteins in FFPE specimens from various pathological states of breast tissue and to compare expression of select known tumor biomarkers in normal and diseased states. Tissue was extracted using an improved protocol that results in enhanced protein yields. We examined FFPE archival breast tissue specimens including 23 normal samples from reduction mammoplasties (control group), 21 fibroadenomas, 25 node negative breast cancers, and 22 node positive breast cancers (test group). Histological subtype and the expression status of estrogen and progesterone receptors, HER2, p53, and Ki-67 were evaluated in the breast cancer specimens. Ten micron FFPE sections were microdissected, de-paraffinized, digested with trypsin, and analyzed by liquid chromatography electrospray ionization mass spectrometry (LC-ESI MS). We developed a novel strategy for MS data mining referred to as “virtual proteomics”, which encompassed diverse mathematical operations on data sets. First, we identified differentially expressed mass/time signals, which were subjected to on- and off-line MS analysis. Data were searched against on-line protein data libraries for the identifications of likely target proteins based on the observed peptide sequences (discovery mode). In parallel, we interrogated the MS data with virtual probes derived from theoretical tryptic digests of known cancer biomarkers (hypothesis testing mode). In the discovery mode, we identified over 5 proteins that were present in >50% specimens in >1 test groups with >10-fold relative differences in expression in comparison with the controls, Mowse scores of >70 (p

Clinical Cancer Research, Nov 15, 2007

B15 Distinct activity profile of pralatrexate (PDX) in human cancer models in vivo and in vitro. ... more B15 Distinct activity profile of pralatrexate (PDX) in human cancer models in vivo and in vitro. Background: PDX (pralatrexate) is a small-molecule inhibitor of dihydrofolate reductase (DHFR), a validated target in oncology. PDX was designed to increase membrane transport and intracellular accumulation compared to methotrexate (MTX), the first DHFR inhibitor used in the clinic despite a narrow therapeutic index, and pemetrexed (PMX), a multitargeted antimetabolite that inhibits multiple folate-dependent enzymes. This pilot study evaluated the mechanism of action of PDX and its differences from other antifolates. Methods: Inhibition of DHFR by the 3 antifolates was quantified in a cell-free assay against human recombinant DHFR. The short-term uptake (assessment of RFC-1 transporter) and folylpolyglutamate synthase (FPGS) activity (polyglutamylation) using radiolabeled PDX, MTX (both at 5 µM) and PMX (20 µM) was evaluated in H460 cells in vitro. We compared in vivo activity of PDX and MTX (both at 1 mg/kg and 2 mg/kg), PMX (150 mg/kg), and docetaxel (7 mg/kg and 12.5 mg/kg) in MV522 and H460, non small cell lung cancer human tumor xenografts models using mean tumor growth inhibition or regression as endpoints. We further evaluated reduced folate carrier (RFC-1) expression by RT PCR in MV522 and H460 xenografts, and measured activity and/or expression of DHFR, TS, and FPGS using kinetic assays and immunostaining ex vivo. Results: As reported recently (Diaz et al, Proc AACR 2007), apparent Ki values for DHFR inhibition in a cell-free assay were, respectively, 6 nM, 12 nM, and >200 nM for PDX, MTX, and PMX. The total uptake of radiolabeled drugs measured at 15 and 60 minutes was similar at both times (MTX), decreased (PMX) or increased (PDX) over time. A significantly smaller fraction of radiolabeled MTX or PMX entered the cells in comparison with PDX. Radiolabeled species (conceivably polyglutamylated PDX) of different Rf values than the drug in a cell-free system appeared in a time-dependent manner in PDX-treated cell extracts. PMX was polyglutamylatated to a lesser extent, and there was no apparent polyglutamylation of MTX. Only PDX demonstrated a clear dose-dependence on distribution of polyglutamylated species. In vivo, PDX was superior to PMX and MTX in both models. A greater dose-dependent inhibition of tumor growth was observed in the more rapidly growing H460 xenografts. Unlike docetaxel, the activity of MTX and PMX was model-dependent. RFC-1 expression was below the assay detection limit in both models. PDX, PMX and MTX demonstrated differences in regulation of enzymatic activity (TS, DHFR) and protein expression (DHFR) in H460 and MV522 tumor xenografts; only PDX downregulated most of these endpoints. Conclusions: The results from this pilot study corroborate earlier notions that PDX has a different activity profile relative to MTX and PMX. Some of the observed differences include enhanced uptake of PDX into tumor cells and subsequent greater intracellular polyglutamylation, which translates into more efficient tumor growth inhibition by PDX in NSCLC xenograft models in vivo. Current findings warrant further studies in other human tumor models including hematologic malignancies. Supported by Allos Therapeutics, Inc.

Nutraceuticals, Dec 17, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Clinical Cancer Research, Nov 15, 2007

A76 Background: Symptoms of lung cancer (LC) often do not appear until the disease is advanced; o... more A76 Background: Symptoms of lung cancer (LC) often do not appear until the disease is advanced; only 15% of LC cases are discovered while the tumor is in the early stages of development. Carcinogen exposure, asthma and smoking have been determined to be risk factors for the development of LC. Prevention and early detection of LC could have a major impact on the natural history of the disease. The objective of the study was to apply multiplexed immunoassays to identify a panel of biomarkers for early detection of LC. Methods: Normal (NO) serum controls (n=30) from healthy volunteers and lung cancer (n=30) were acquired from a commercial vendor. Baseline (pre-treatment) serum specimens from individuals with asthma (AST; n=30) and lung cancer risk (LCR; n=73) were available from clinical trials of two novel agents that are being developed by JBNI Inc. for the respective indications. Serum levels of 59 cytokines, growth factors and biologically active peptides were quantified using multiplexed immunoassays using the Luminex platform to identify biomarkers that are expressed in a significantly different manner in individuals with LC, LCR, or AST in comparison with NO subjects. Data were reduced using nearest neighbor cluster analysis with squared Euclidian distance to separate patients into groups across analytes with inter-pathology comparisons determined using Student’s t test. Results and conclusions: Multiple analytes showed highly significant differences (p

Clinical Cancer Research, Nov 15, 2007

A76 Background: Symptoms of lung cancer (LC) often do not appear until the disease is advanced; o... more A76 Background: Symptoms of lung cancer (LC) often do not appear until the disease is advanced; only 15% of LC cases are discovered while the tumor is in the early stages of development. Carcinogen exposure, asthma and smoking have been determined to be risk factors for the development of LC. Prevention and early detection of LC could have a major impact on the natural history of the disease. The objective of the study was to apply multiplexed immunoassays to identify a panel of biomarkers for early detection of LC. Methods: Normal (NO) serum controls (n=30) from healthy volunteers and lung cancer (n=30) were acquired from a commercial vendor. Baseline (pre-treatment) serum specimens from individuals with asthma (AST; n=30) and lung cancer risk (LCR; n=73) were available from clinical trials of two novel agents that are being developed by JBNI Inc. for the respective indications. Serum levels of 59 cytokines, growth factors and biologically active peptides were quantified using multiplexed immunoassays using the Luminex platform to identify biomarkers that are expressed in a significantly different manner in individuals with LC, LCR, or AST in comparison with NO subjects. Data were reduced using nearest neighbor cluster analysis with squared Euclidian distance to separate patients into groups across analytes with inter-pathology comparisons determined using Student’s t test. Results and conclusions: Multiple analytes showed highly significant differences (p

Pharmaceuticals, Jun 21, 2023

Journal of Clinical Oncology, Jul 15, 2004

3136 Background: R115777 (tipifarnib, ZARNESTRA), an oral methyl quinolinone selectively inhibits... more 3136 Background: R115777 (tipifarnib, ZARNESTRA), an oral methyl quinolinone selectively inhibits farnesyl transferase, a critical enzyme in several cell signal transduction pathways. The preclinic...

Clinical Cancer Research, Aug 1, 2004

Purpose: To assess the feasibility of administering oblimersen sodium, a phosphorothioate antisen... more Purpose: To assess the feasibility of administering oblimersen sodium, a phosphorothioate antisense oligonucleotide directed to the Bcl-2 mRNA, with docetaxel to patients with hormone-refractory prostate cancer; to characterize the pertinent pharmacokinetic parameters, Bcl-2 protein inhibition in peripheral blood mononuclear cell(s) (PBMC) and tumor; and to seek preliminary evidence of antitumor activity. Experimental Design: Patients were treated with increasing doses of oblimersen sodium administered by continuous i.v. infusion on days 1 to 6 and docetaxel administered i.v. over 1 h on day 6 every 3 weeks. Plasma was sampled to characterize the pharmacokinetic parameters of both oblimersen and docetaxel, and Bcl-2 protein expression was measured from paired collections of PBMCs pretreatment and post-treatment. Results: Twenty patients received 124 courses of the oblimersen and docetaxel combination at doses ranging from 5 to 7 mg/kg/day oblimersen and 60 to 100 mg/m 2 docetaxel. The rate of severe fatigue accompanied by severe neutropenia was unacceptably high at doses exceeding 7 mg/kg/day oblimersen and 75 mg/m 2 docetaxel. Nausea, vomiting, and fever were common, but rarely severe. Oblimersen mean steady-state concentrations were 3.44 ؎ 1.31 and 5.32 ؎ 2.34 at the 5-and 7-mg/kg dose levels, respectively. Prostate-specific antigen responses were observed in 7 of 12 taxane-naïve patients, but in taxane-refractory patients no responses were observed. Preliminary evaluation of Bcl-2 expression in diagnostic tumor specimens was not predictive of response to this therapy. Conclusions: The recommended Phase II doses for oblimersen and docetaxel on this schedule are 7 mg/kg/day continuous i.v. infusion days 1 to 6, and 75 mg/m 2 i.v. day 6, respectively, once every 3 weeks. The absence of severe toxicities at this recommended dose, evidence of Bcl-2 protein inhibition in PBMC and tumor tissue, and encouraging antitumor activity in HPRC patients warrant further clinical evaluation of this combination.

… of the American …, 2004

4016 Pivanex™ (pivaloyloxymethyl butyrate) is a histone deacetylase (HDAC) inhibitor that distrib... more 4016 Pivanex™ (pivaloyloxymethyl butyrate) is a histone deacetylase (HDAC) inhibitor that distributes rapidly into tissues and induces cell differentiation, leading to apoptosis in a wide range of tumor cells examined. Pivanex is very well tolerated, and has demonstrated phase II single-agent activity in non-small cell lung cancer (NSCLC) patients with refractory or relapsed disease. It is currently in a phase IIb randomized, controlled study in combination with docetaxel (Taxotere™) in second line treatment of NSCLC. Using the NCI-H23 human NSCLC cell line as a model for Pivanex’s activity, we examined HDAC inhibition at various time points following a single in vitro addition of Pivanex. Hyperacetylation of histones 3 and 4 were quantified by Western blot analysis, and HDAC activity was determined with a fluorescent-substrate based enzyme activity assay (Biomol, Inc.). HDAC activity was then evaluated in NSCLC patient peripheral blood mononuclear cells (PBMCs) before and after treatment with Pivanex. Pivanex was administered by 6-hr infusions on 3 consecutive days at a dose of 2.5 g/m2. Blood samples were collected just before starting Pivanex treatment (day 1) and the day after a course of Pivanex infusion (day 4). PBMCs were isolated with sodium citrate Vacutainer-CPT tubes (Becton Dickinson) and frozen until analysis. PBMC pellets were lysed in osmotic lysing buffer containing 1% protease and phosphatase inhibitor cocktails (Sigma) with or without 0.3% SDS, respectively, for Western blot and HDAC activity assays. The total protein concentration was determined with BCA reagent (Pierce) and equal amounts of total protein were analyzed. Results: For NCI-H23 NSCLC cells, a single treatment with Pivanex resulted in the hyperacetylation of histone 3 at 1, 3, 7, 24 and 48 hours. HDAC enzyme activity was found to be inhibited at all time points examined: 1, 3, 5, 7, 24, 48, and 72 hours; with maximum inhibition to 25% at 72 hours. Pivanex-treatment in the clinic also resulted in the hyperacetylation of histones 3 and 4 in patient-derived PBMCs, one day after initial infusion. In addition, HDAC activity from patient PBMCs on day 4 was also strongly inhibited after Pivanex treatment. Conclusion: Pivanex treatment in the clinic results in the inhibition of HDAC enzyme activity leading to the hyperacetylation of histones as previously demonstrated in in vitro experiments. PBMCs from patients undergoing Pivanex therapy can thus be monitored for the activity of this potent HDAC inhibitor.

European Journal of Cancer, 2012

Chemischer Informationsdienst, 1979

Annals of Oncology, Nov 1, 1997

Background: Telomerase is an important enzyme whose activity has been convincingly demonstrated i... more Background: Telomerase is an important enzyme whose activity has been convincingly demonstrated in humans recently. It is required for maintenance of ends of chromosomes (telomeres) during cell division. Since its presence has been selectively demonstrated in dividing cells including tumor cells, it has generated considerable excitement as a potential anticancer strategy. Design: In this article, we review the current relevant biology of the enzyme, the challenges encountered in the preclinical phase of target development and the current efforts that focus on telomeres and telomerase as therapeutic targets. We also speculate on the potential toxicities and mechanisms of resistance that may be encountered during use of such therapies.

Anti-cancer drug design, 1999

Cationic porphyrins, which interact with guanine quadruplex (G4) telomeric folds, inhibit telomer... more Cationic porphyrins, which interact with guanine quadruplex (G4) telomeric folds, inhibit telomerase activity in human tumor cells. In this study, we have further examined effects of porphyrins and other telomere- and telomerase-interactive agents on proliferation rates and chromosome stability in a novel in vivo model, developing sea urchin embryos. We studied two porphyrins: (i) TMPyP4, a potent telomerase inhibitor; and (ii) TMPyP2, an isomer of TMPyP4 and an inefficient telomerase inhibitor, azidothymine (AZT), the reverse transcriptase inhibitor, antisense phosphorothioate oligonucleotide to telomerase RNA (TAG6) and a control scrambled sequence (ODN). TMPyP4, AZT and TAG6 (but not TMPyP2 or ODN) decreased the rates of cell proliferation and increased the percentage of cells trapped in mitosis. Nuclear localization of TAG6, but not of ODN, was demonstrated with 5'-fluoresceinated analogs of TAG6 and ODN. Formation of elongated chromosomes incapable of separating in anaphase...

Molecular Cancer Therapeutics, 2007

A135 This pilot study investigated the mechanism of action of PDX and its differences from other ... more A135 This pilot study investigated the mechanism of action of PDX and its differences from other antifolates, and compared the in vivo activity of 3 antifolates against 2 NSCLC models. In vitro studies included evaluation of reduced folate carrier (RFC) expression by reverse transcription polymerase chain reaction (RT PCR) in MV522 and H460 xenograft models. We also compared the short-term uptake (assessment of RFC-1 transporter) and folylpolyglutamate synthase (FPGS) activity (polyglutamylation) using radiolabeled PDX, MTX (both at 5 µM) and Alimta (20 µM) in H460 cells in vitro. Inhibition of DHFR by the 3 antifolates was quantified in a cell-free assay against human recombinant DHFR. We compared in vivo activity of PDX and MTX (both at 1 mg/kg and 2 mg/kg), and Alimta (150 mg/kg) in the MV522 and H460 xenografts. Endpoints included mean tumor growth inhibition or regression. We further evaluated activity and/or expression of certain folate-dependent enzymes: DHFR, TS, and FPGS us...

Lung Cancer, May 1, 2009

Conclusions: It seems to be supported by evidence that severe alterations in bronchial mucosa hap... more Conclusions: It seems to be supported by evidence that severe alterations in bronchial mucosa happen in advanced COPD and 25% of them become precancerous lesions and even 1.6% are positive for neoplasia. That corroborates many authors' hypothesis that lung cancer can be considered such as real complication of severe COPD and that inflammation is a decisive factor with the immune mechanism correlation.

Cancer Research, May 1, 2007

5586 MBP-426 is a novel oxaliplatin-encapsulated transferrin (Tf) -conjugated N-glutaryl phosphat... more 5586 MBP-426 is a novel oxaliplatin-encapsulated transferrin (Tf) -conjugated N-glutaryl phosphatidylethanolamine (NGPE)-liposome. MBP-426 demonstrated potent anticancer preclinical activity and has recently entered clinical trials. Direct drug binding to Tf receptor (TfR) was demonstrated in human cancer cells in vitro; the drug delivery is thought to be enhanced via uptake by TfR. This study investigated activity of MBP-426 alone and in combination with gemcitabine or erlotinib in the PANC-1 human pancreas tumor xenograft model. Significant endpoints included mean tumor growth inhibition or regression, weight loss, and agent toxicity. In groups treated with MBP-426 alone and in combination with gemcitabine we further evaluated expression of biomarkers (TfR, cleaved caspase-3, PARP, survivin, CD31, Hif1a in tumor tissue; VEGF, TNF-a, bFGF, IL-6, MMP-2 and MMP-9 in serum) by immunostaining and multiplexed immunoassays, respectively. In vivo treatment with gemcitabine (40 mg/kg) resulted in reversible weight loss and moderate tumor growth inhibition (TGI=25%); no weight loss or TGI was reported for 50 mg/kg erlotinib. MBP-426 alone was inactive but the group co-treated with 40 mg/kg gemcitabine and 4 mg/kg MBP-426 reported significant (p 20% inhibition, p=0.011) in the 4 mg/kg MBP-426 plus gemcitabine treatment group. TNF-a was significantly suppressed by gemcitabine (50% inhibition, p=0.007), the low dose of MBP-426 alone (35% inhibition, p=0.043) and in combination with gemcitabine (38% inhibition, p=0.027). Taken together, these results demonstrate additive combinatorial effects of MBP-426 with gemcitabine and erlotinib in pancreatic adenocarcinoma in vivo. Serum TNF-a and MMP-2 levels might be pursued as potential biomarkers of drug efficacy in clinical trials. Supported by Mebiopharm

The goal of personalized medicine is to enhance our understanding of the disease at the molecular... more The goal of personalized medicine is to enhance our understanding of the disease at the molecular level and optimize drug treatment to best meet the needs of an individual. In addition to genomic biomarkers for drug response, the mitochondrial genome (mtDNA) ...

PubMed, Oct 15, 2003

Purpose: To assess the feasibility of administering tipifarnib, an oral nonpeptidomimetic competi... more Purpose: To assess the feasibility of administering tipifarnib, an oral nonpeptidomimetic competitive inhibitor of farnesyltransferase, in combination with gemcitabine and recommend doses for disease-directed clinical trials. The study also sought to identify drug-drug pharmacokinetic interactions, evaluate effects on protein farnesylation, and seek preliminary evidence for clinical activity. Experimental design: Patients with advanced solid malignancies were treated with tipifarnib at doses of 100, 200, and 300 mg twice daily continuously and 1000 mg/m(2) gemcitabine i.v. on days 1, 8, and 15 every 4 weeks. To identify pharmacokinetic interactions, the treatment and plasma sampling schemes were designed to permit comparisons of the pharmacokinetic behavior of each agent administered alone and together. The proportions of unfarnesylated and farnesylated HDJ2, a chaperone protein that undergoes farnesylation, were measured in peripheral blood mononuclear cells. Results: Nineteen evaluable patients were treated with 74 courses of tipifarnib/gemcitabine (mg/mg/m(2)). Myelosuppression was the principal toxicity. Dose-limiting myelosuppression occurred in 2 of 5 patients at the 300/1000 dose level, whereas 2 of 11 evaluable patients at the 200/1000 dose level experienced dose-limiting toxicity. There was no evidence of clinically relevant pharmacokinetic interactions between tipifarnib and gemcitabine. Inhibition of farnesylation of HDJ2, a potential surrogate for Ras and/or other potentially relevant farnesylated proteins, was demonstrated in peripheral blood mononuclear cells at all dose levels. Partial responses were noted in patients with advanced pancreatic and nasopharyngeal carcinomas. Conclusions: On the basis of the results of this study, the tipifarnib/gemcitabine dose level of 200/1000 is recommended for disease-directed studies. At this dose level, biologically relevant plasma concentrations of tipifarnib that consistently inhibit protein farnesylation in vitro are achieved and drug-induced inhibition of protein farnesylation is measured in most patients.

Clinical Cancer Research, Oct 1, 2007

A9 The goal of personalized medicine is to deliver the best treatment to the patient. In clinical... more A9 The goal of personalized medicine is to deliver the best treatment to the patient. In clinical oncology, proteomics can evaluate differential expression and post-translational modifications of proteins in healthy and diseased states. Given that many novel anticancer therapies are designed to target tumor proteins, proteomic analysis of tumor tissue should complement conventional genomic or immunohistochemical (IHC) analyses in delivering information relevant for diagnosis, prognosis and predicting tumor response to treatment. Formalin fixation and paraffin embedding (FFPE) of diagnostic specimens is the preparation method of choice for pathological assessment. We undertook this study to identify differentially expressed proteins in FFPE specimens from various pathological states of breast tissue and to compare expression of select known tumor biomarkers in normal and diseased states. Tissue was extracted using an improved protocol that results in enhanced protein yields. We examined FFPE archival breast tissue specimens including 23 normal samples from reduction mammoplasties (control group), 21 fibroadenomas, 25 node negative breast cancers, and 22 node positive breast cancers (test group). Histological subtype and the expression status of estrogen and progesterone receptors, HER2, p53, and Ki-67 were evaluated in the breast cancer specimens. Ten micron FFPE sections were microdissected, de-paraffinized, digested with trypsin, and analyzed by liquid chromatography electrospray ionization mass spectrometry (LC-ESI MS). We developed a novel strategy for MS data mining referred to as “virtual proteomics”, which encompassed diverse mathematical operations on data sets. First, we identified differentially expressed mass/time signals, which were subjected to on- and off-line MS analysis. Data were searched against on-line protein data libraries for the identifications of likely target proteins based on the observed peptide sequences (discovery mode). In parallel, we interrogated the MS data with virtual probes derived from theoretical tryptic digests of known cancer biomarkers (hypothesis testing mode). In the discovery mode, we identified over 5 proteins that were present in >50% specimens in >1 test groups with >10-fold relative differences in expression in comparison with the controls, Mowse scores of >70 (p

Clinical Cancer Research, Nov 15, 2007

B15 Distinct activity profile of pralatrexate (PDX) in human cancer models in vivo and in vitro. ... more B15 Distinct activity profile of pralatrexate (PDX) in human cancer models in vivo and in vitro. Background: PDX (pralatrexate) is a small-molecule inhibitor of dihydrofolate reductase (DHFR), a validated target in oncology. PDX was designed to increase membrane transport and intracellular accumulation compared to methotrexate (MTX), the first DHFR inhibitor used in the clinic despite a narrow therapeutic index, and pemetrexed (PMX), a multitargeted antimetabolite that inhibits multiple folate-dependent enzymes. This pilot study evaluated the mechanism of action of PDX and its differences from other antifolates. Methods: Inhibition of DHFR by the 3 antifolates was quantified in a cell-free assay against human recombinant DHFR. The short-term uptake (assessment of RFC-1 transporter) and folylpolyglutamate synthase (FPGS) activity (polyglutamylation) using radiolabeled PDX, MTX (both at 5 µM) and PMX (20 µM) was evaluated in H460 cells in vitro. We compared in vivo activity of PDX and MTX (both at 1 mg/kg and 2 mg/kg), PMX (150 mg/kg), and docetaxel (7 mg/kg and 12.5 mg/kg) in MV522 and H460, non small cell lung cancer human tumor xenografts models using mean tumor growth inhibition or regression as endpoints. We further evaluated reduced folate carrier (RFC-1) expression by RT PCR in MV522 and H460 xenografts, and measured activity and/or expression of DHFR, TS, and FPGS using kinetic assays and immunostaining ex vivo. Results: As reported recently (Diaz et al, Proc AACR 2007), apparent Ki values for DHFR inhibition in a cell-free assay were, respectively, 6 nM, 12 nM, and >200 nM for PDX, MTX, and PMX. The total uptake of radiolabeled drugs measured at 15 and 60 minutes was similar at both times (MTX), decreased (PMX) or increased (PDX) over time. A significantly smaller fraction of radiolabeled MTX or PMX entered the cells in comparison with PDX. Radiolabeled species (conceivably polyglutamylated PDX) of different Rf values than the drug in a cell-free system appeared in a time-dependent manner in PDX-treated cell extracts. PMX was polyglutamylatated to a lesser extent, and there was no apparent polyglutamylation of MTX. Only PDX demonstrated a clear dose-dependence on distribution of polyglutamylated species. In vivo, PDX was superior to PMX and MTX in both models. A greater dose-dependent inhibition of tumor growth was observed in the more rapidly growing H460 xenografts. Unlike docetaxel, the activity of MTX and PMX was model-dependent. RFC-1 expression was below the assay detection limit in both models. PDX, PMX and MTX demonstrated differences in regulation of enzymatic activity (TS, DHFR) and protein expression (DHFR) in H460 and MV522 tumor xenografts; only PDX downregulated most of these endpoints. Conclusions: The results from this pilot study corroborate earlier notions that PDX has a different activity profile relative to MTX and PMX. Some of the observed differences include enhanced uptake of PDX into tumor cells and subsequent greater intracellular polyglutamylation, which translates into more efficient tumor growth inhibition by PDX in NSCLC xenograft models in vivo. Current findings warrant further studies in other human tumor models including hematologic malignancies. Supported by Allos Therapeutics, Inc.

Nutraceuticals, Dec 17, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Clinical Cancer Research, Nov 15, 2007

A76 Background: Symptoms of lung cancer (LC) often do not appear until the disease is advanced; o... more A76 Background: Symptoms of lung cancer (LC) often do not appear until the disease is advanced; only 15% of LC cases are discovered while the tumor is in the early stages of development. Carcinogen exposure, asthma and smoking have been determined to be risk factors for the development of LC. Prevention and early detection of LC could have a major impact on the natural history of the disease. The objective of the study was to apply multiplexed immunoassays to identify a panel of biomarkers for early detection of LC. Methods: Normal (NO) serum controls (n=30) from healthy volunteers and lung cancer (n=30) were acquired from a commercial vendor. Baseline (pre-treatment) serum specimens from individuals with asthma (AST; n=30) and lung cancer risk (LCR; n=73) were available from clinical trials of two novel agents that are being developed by JBNI Inc. for the respective indications. Serum levels of 59 cytokines, growth factors and biologically active peptides were quantified using multiplexed immunoassays using the Luminex platform to identify biomarkers that are expressed in a significantly different manner in individuals with LC, LCR, or AST in comparison with NO subjects. Data were reduced using nearest neighbor cluster analysis with squared Euclidian distance to separate patients into groups across analytes with inter-pathology comparisons determined using Student’s t test. Results and conclusions: Multiple analytes showed highly significant differences (p

Clinical Cancer Research, Nov 15, 2007

A76 Background: Symptoms of lung cancer (LC) often do not appear until the disease is advanced; o... more A76 Background: Symptoms of lung cancer (LC) often do not appear until the disease is advanced; only 15% of LC cases are discovered while the tumor is in the early stages of development. Carcinogen exposure, asthma and smoking have been determined to be risk factors for the development of LC. Prevention and early detection of LC could have a major impact on the natural history of the disease. The objective of the study was to apply multiplexed immunoassays to identify a panel of biomarkers for early detection of LC. Methods: Normal (NO) serum controls (n=30) from healthy volunteers and lung cancer (n=30) were acquired from a commercial vendor. Baseline (pre-treatment) serum specimens from individuals with asthma (AST; n=30) and lung cancer risk (LCR; n=73) were available from clinical trials of two novel agents that are being developed by JBNI Inc. for the respective indications. Serum levels of 59 cytokines, growth factors and biologically active peptides were quantified using multiplexed immunoassays using the Luminex platform to identify biomarkers that are expressed in a significantly different manner in individuals with LC, LCR, or AST in comparison with NO subjects. Data were reduced using nearest neighbor cluster analysis with squared Euclidian distance to separate patients into groups across analytes with inter-pathology comparisons determined using Student’s t test. Results and conclusions: Multiple analytes showed highly significant differences (p

Pharmaceuticals, Jun 21, 2023

Journal of Clinical Oncology, Jul 15, 2004

3136 Background: R115777 (tipifarnib, ZARNESTRA), an oral methyl quinolinone selectively inhibits... more 3136 Background: R115777 (tipifarnib, ZARNESTRA), an oral methyl quinolinone selectively inhibits farnesyl transferase, a critical enzyme in several cell signal transduction pathways. The preclinic...

Clinical Cancer Research, Aug 1, 2004

Purpose: To assess the feasibility of administering oblimersen sodium, a phosphorothioate antisen... more Purpose: To assess the feasibility of administering oblimersen sodium, a phosphorothioate antisense oligonucleotide directed to the Bcl-2 mRNA, with docetaxel to patients with hormone-refractory prostate cancer; to characterize the pertinent pharmacokinetic parameters, Bcl-2 protein inhibition in peripheral blood mononuclear cell(s) (PBMC) and tumor; and to seek preliminary evidence of antitumor activity. Experimental Design: Patients were treated with increasing doses of oblimersen sodium administered by continuous i.v. infusion on days 1 to 6 and docetaxel administered i.v. over 1 h on day 6 every 3 weeks. Plasma was sampled to characterize the pharmacokinetic parameters of both oblimersen and docetaxel, and Bcl-2 protein expression was measured from paired collections of PBMCs pretreatment and post-treatment. Results: Twenty patients received 124 courses of the oblimersen and docetaxel combination at doses ranging from 5 to 7 mg/kg/day oblimersen and 60 to 100 mg/m 2 docetaxel. The rate of severe fatigue accompanied by severe neutropenia was unacceptably high at doses exceeding 7 mg/kg/day oblimersen and 75 mg/m 2 docetaxel. Nausea, vomiting, and fever were common, but rarely severe. Oblimersen mean steady-state concentrations were 3.44 ؎ 1.31 and 5.32 ؎ 2.34 at the 5-and 7-mg/kg dose levels, respectively. Prostate-specific antigen responses were observed in 7 of 12 taxane-naïve patients, but in taxane-refractory patients no responses were observed. Preliminary evaluation of Bcl-2 expression in diagnostic tumor specimens was not predictive of response to this therapy. Conclusions: The recommended Phase II doses for oblimersen and docetaxel on this schedule are 7 mg/kg/day continuous i.v. infusion days 1 to 6, and 75 mg/m 2 i.v. day 6, respectively, once every 3 weeks. The absence of severe toxicities at this recommended dose, evidence of Bcl-2 protein inhibition in PBMC and tumor tissue, and encouraging antitumor activity in HPRC patients warrant further clinical evaluation of this combination.

… of the American …, 2004

4016 Pivanex™ (pivaloyloxymethyl butyrate) is a histone deacetylase (HDAC) inhibitor that distrib... more 4016 Pivanex™ (pivaloyloxymethyl butyrate) is a histone deacetylase (HDAC) inhibitor that distributes rapidly into tissues and induces cell differentiation, leading to apoptosis in a wide range of tumor cells examined. Pivanex is very well tolerated, and has demonstrated phase II single-agent activity in non-small cell lung cancer (NSCLC) patients with refractory or relapsed disease. It is currently in a phase IIb randomized, controlled study in combination with docetaxel (Taxotere™) in second line treatment of NSCLC. Using the NCI-H23 human NSCLC cell line as a model for Pivanex’s activity, we examined HDAC inhibition at various time points following a single in vitro addition of Pivanex. Hyperacetylation of histones 3 and 4 were quantified by Western blot analysis, and HDAC activity was determined with a fluorescent-substrate based enzyme activity assay (Biomol, Inc.). HDAC activity was then evaluated in NSCLC patient peripheral blood mononuclear cells (PBMCs) before and after treatment with Pivanex. Pivanex was administered by 6-hr infusions on 3 consecutive days at a dose of 2.5 g/m2. Blood samples were collected just before starting Pivanex treatment (day 1) and the day after a course of Pivanex infusion (day 4). PBMCs were isolated with sodium citrate Vacutainer-CPT tubes (Becton Dickinson) and frozen until analysis. PBMC pellets were lysed in osmotic lysing buffer containing 1% protease and phosphatase inhibitor cocktails (Sigma) with or without 0.3% SDS, respectively, for Western blot and HDAC activity assays. The total protein concentration was determined with BCA reagent (Pierce) and equal amounts of total protein were analyzed. Results: For NCI-H23 NSCLC cells, a single treatment with Pivanex resulted in the hyperacetylation of histone 3 at 1, 3, 7, 24 and 48 hours. HDAC enzyme activity was found to be inhibited at all time points examined: 1, 3, 5, 7, 24, 48, and 72 hours; with maximum inhibition to 25% at 72 hours. Pivanex-treatment in the clinic also resulted in the hyperacetylation of histones 3 and 4 in patient-derived PBMCs, one day after initial infusion. In addition, HDAC activity from patient PBMCs on day 4 was also strongly inhibited after Pivanex treatment. Conclusion: Pivanex treatment in the clinic results in the inhibition of HDAC enzyme activity leading to the hyperacetylation of histones as previously demonstrated in in vitro experiments. PBMCs from patients undergoing Pivanex therapy can thus be monitored for the activity of this potent HDAC inhibitor.

European Journal of Cancer, 2012

Chemischer Informationsdienst, 1979

Annals of Oncology, Nov 1, 1997

Background: Telomerase is an important enzyme whose activity has been convincingly demonstrated i... more Background: Telomerase is an important enzyme whose activity has been convincingly demonstrated in humans recently. It is required for maintenance of ends of chromosomes (telomeres) during cell division. Since its presence has been selectively demonstrated in dividing cells including tumor cells, it has generated considerable excitement as a potential anticancer strategy. Design: In this article, we review the current relevant biology of the enzyme, the challenges encountered in the preclinical phase of target development and the current efforts that focus on telomeres and telomerase as therapeutic targets. We also speculate on the potential toxicities and mechanisms of resistance that may be encountered during use of such therapies.

Anti-cancer drug design, 1999

Cationic porphyrins, which interact with guanine quadruplex (G4) telomeric folds, inhibit telomer... more Cationic porphyrins, which interact with guanine quadruplex (G4) telomeric folds, inhibit telomerase activity in human tumor cells. In this study, we have further examined effects of porphyrins and other telomere- and telomerase-interactive agents on proliferation rates and chromosome stability in a novel in vivo model, developing sea urchin embryos. We studied two porphyrins: (i) TMPyP4, a potent telomerase inhibitor; and (ii) TMPyP2, an isomer of TMPyP4 and an inefficient telomerase inhibitor, azidothymine (AZT), the reverse transcriptase inhibitor, antisense phosphorothioate oligonucleotide to telomerase RNA (TAG6) and a control scrambled sequence (ODN). TMPyP4, AZT and TAG6 (but not TMPyP2 or ODN) decreased the rates of cell proliferation and increased the percentage of cells trapped in mitosis. Nuclear localization of TAG6, but not of ODN, was demonstrated with 5'-fluoresceinated analogs of TAG6 and ODN. Formation of elongated chromosomes incapable of separating in anaphase...

Molecular Cancer Therapeutics, 2007

A135 This pilot study investigated the mechanism of action of PDX and its differences from other ... more A135 This pilot study investigated the mechanism of action of PDX and its differences from other antifolates, and compared the in vivo activity of 3 antifolates against 2 NSCLC models. In vitro studies included evaluation of reduced folate carrier (RFC) expression by reverse transcription polymerase chain reaction (RT PCR) in MV522 and H460 xenograft models. We also compared the short-term uptake (assessment of RFC-1 transporter) and folylpolyglutamate synthase (FPGS) activity (polyglutamylation) using radiolabeled PDX, MTX (both at 5 µM) and Alimta (20 µM) in H460 cells in vitro. Inhibition of DHFR by the 3 antifolates was quantified in a cell-free assay against human recombinant DHFR. We compared in vivo activity of PDX and MTX (both at 1 mg/kg and 2 mg/kg), and Alimta (150 mg/kg) in the MV522 and H460 xenografts. Endpoints included mean tumor growth inhibition or regression. We further evaluated activity and/or expression of certain folate-dependent enzymes: DHFR, TS, and FPGS us...