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Kevin P Rice - One of the best experts on this subject based on the ideXlab platform.
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abstract 266 relationship between bag3 expression and the cytotoxicity of Laromustine in hl60 cells
Cancer Research, 2019Co-Authors: Stanley R Clarke, Allie H Naccara, Amanda J Loya, Sam W Marchant, Xiaoou Wang, Thomas J Lajoie, Jordyn Smith, Kevin P RiceAbstract:Laromustine is an experimental sulfonylhydrazine prodrug with clinical potential against acute myelogenous leukemia and glioblastoma multiforme. Cytotoxicity is largely due to DNA crosslinking activity from an electrophilic subspecies of Laromustine generated in situ. However, methylisocyanate, another electrophile cogenerated upon base-catalyzed activation of Laromustine, induces acute toxicity in cultured leukemia cells. Isocyanate-mediated cytotoxicity likely involves apoptotic processes revealed in experiments presented herein showing PARP cleavage, caspase 3/7 activation, and annexin-V staining. We demonstrate that compounds that yield methylisocyanate, including Laromustine, cause substantial dysregulation of gene transcription patterns that are not observed with a derivative of Laromustine that possesses the DNA crosslinking activity but not the methylisocyanate. Purified mRNA from promyelocytic HL60 cells treated with either 100 µM agent or an equivalent volume of DMSO was measured using real-time RT-PCR experiments and GeneChip analyses. Among the nearly 3,000 genes dysregulated upon exposure to both Laromustine and its methylisocyanate-bearing analog, BCL2-associated athanogene 3 (BAG3) emerged as a promising candidate for further investigation. This anti-apoptotic gene was significantly upregulated in these conditions. So as to assess the significance its gene product in cell death or survival in cultured cells treated with Laromustine, a stable cell line expressing an shRNA construct to knock down BAG3 was engineered from HL60 cells using lentiviruses. Preliminary evidence suggests that these cells are more susceptible to the cytotoxic effects of Laromustine. These data suggest that BAG3 may be part of a defensive strategy for promyelocytic leukemia cells to survive treatment with Laromustine. Citation Format: Stanley R. Clarke, Allie H. Naccara, Amanda J. Loya, Sam W. Marchant, Xiaoou Wang, Thomas J. LaJoie, Jordyn N. Smith, Kevin P. Rice. Relationship between BAG3 expression and the cytotoxicity of Laromustine in HL60 cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 266.
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abstract 2109 transcriptional analysis of human leukemia cells treated with the experimental anticancer drug Laromustine
Cancer Research, 2017Co-Authors: Amanda J Loya, Dylan J Cincotta, Abdel G Elkahloun, David M Bodine, Kevin P RiceAbstract:Laromustine is an experimental anticancer prodrug that demonstrated significant activity against acute myeloid leukemia in human clinical trials. Upon base-catalyzed activation, Laromustine yields two reactive, electrophilic species in situ: 90CE, which can chloroethylate the O6 position of guanine in DNA causing lethal interstrand crosslinks, and methyl isocyanate, which can carbamoylate biochemically relevant nucleophiles, such as cysteine sulfhydryl groups. Previous in vitro and ex vivo investigations into Laromustine’s molecular mechanism of action reveal several biochemical consequences of methyl isocyanate, many of which may explain either the acute cytotoxicity of the drug’s carbamoylating activity or the observed synergism with the cytotoxicity of guanine O6 chloroethylation. The combined activities of the electrophilic subspecies of Laromustine are believed to induce apoptosis in leukemia cells. Presented herein are extensive flow cytometry experiments using FITC-AnnexinV and propidium iodide suggesting a dose-dependent cytotoxicity that includes apoptotosis. So as to gain a more complete understanding of the drug’s toxicity, an investigation into how Laromustine modulates gene transcription in HL60 cells is also carried out and reported here. Total mRNA was harvested from cultured HL60 cells treated with sub-lethal doses of Laromustine or analogs lacking either carbamoylating or chloroethylating activity. These samples were subjected to GeneChip analyses against control mRNA. More than 4,000 genes were significantly dysregulated upon the cells’ exposure to Laromustine. The analog of Laromustine possessing only carbamoylating activity caused the dysregulation of nearly 3,000 genes, the vast majority of which were also dysregulated in response to Laromustine. 90CE, which lacks carbamoylating activity but retains chloroethylating activity, understood to be principally responsible for therapeutic cytotoxicity, demonstrated very little effect on gene transcription in HL60 cells. Preliminary analysis of gene pathways affected by Laromustine suggests that among the altered pathways, those associated with cancer progression, the G1/S checkpoint, and hematological disorders are particularly stressed. The carbamoylating activity of Laromustine is responsible for most of these effects. Identifying genetic pathways disrupted by this potentially useful drug may inform clinical strategies or identify potential targets for co-therapeutic agents. Citation Format: Amanda J. Loya, Dylan J. Cincotta, Abdel Elkahloun, David Bodine, Kevin P. Rice. Transcriptional analysis of human leukemia cells treated with the experimental anticancer drug Laromustine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2109. doi:10.1158/1538-7445.AM2017-2109
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abstract 4777 the role of bag3 in human leukemia cells response to the experimental anticancer drug Laromustine
Cancer Research, 2016Co-Authors: Kevin P Rice, Amanda J Loya, Kayla M GrossAbstract:The experimental anticancer drug Laromustine, which demonstrates moderate clinical efficacy against acute myelogenous leukemia and glioblastoma multiforme, yields two reactive electrophiles in situ. Therapeutic cytotoxicity is principally due to a 2-chloroethylating species that can cause lethal DNA crosslinks. However, the second electrophile, methyl isocyanate, triggers acute toxicity in cultured cancer cells and synergizes with the cogenerated 2-chloroethylating activity. The mechanism by which Laromustine kills cancer cells likely includes apoptosis. We measured changes in transcription for 88 genes relating to this cell death pathway cultured human promyelocytic (HL-60) cells using quantitative real-time reverse transcriptase PCR. Cultured cells were treated with drug for six hours before harvesting mRNA for analysis. Of these genes, the expression of BAG3, whose encoded protein is also known as CAIR-1 or Bis, was increased by more than 300 fold in cells exposed to Laromustine. By forming a complex with heat shock protein 70 (Hsp70), it is thought that BAG3 promotes anti-apoptotic activity by interfering with protein chaperones and release of cytochrome-c. We are also examining effects on the entire transcriptome upon treatment with Laromustine using GeneChip Microarrays. Finally, we have created a stable BAG3 knockdown cell line using an shRNA construct via lentiviral transfection. Substantial differences in Laromustine-induced cytotoxicity in differing BAG3 backgrounds would suggest a mechanistic role in a cell9s defense against Laromustine and possibly an improved clinical approach. Citation Format: Kevin P. Rice, Amanda J. Loya, Kayla M. Gross. The role of BAG3 in human leukemia cells’ response to the experimental anticancer drug Laromustine. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4777.
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abstract 5498 changes in expression of dna repair genes in human leukemia cells treated with Laromustine
Cancer Research, 2014Co-Authors: Kristen N Robinson, Kathryn Coe, Justin E Owumi, Kevin P RiceAbstract:Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA The anticancer prodrug Laromustine induces cytotoxic DNA damage and has had clinical success against acute myelogenous leukemia and glioblastoma multiforme. The causative DNA damage is principally a G-C interstrand crosslink preceded by 2-chloroethylation of guanine O6 by a subspecies of Laromustine generated in situ upon base-catalyzed activation. Another cogenerated electrophile, methylisocyanate, contributes synergistically with the DNA alkylating activity towards cytotoxicity. Given this synergism, DNA repair enzymes are considered likely targets of methylisocyanate, which can carbamoylate amines and sulfhydryls. The inhibition of O6-alkylguanine-DNA alkyltransferase (AGT) and DNA polymerase beta by laroumustine's carbamoylating activity, observed in vitro, may contribute to cytotoxicity. To further investigate the relationship between Laromustine and DNA repair, drug-induced changes in the transcription of 88 DNA repair genes were measured in cultured human promyelocytic (HL-60) cells using quantitative real-time reverse transcriptase PCR. Cells were treated with Laromustine or vehicle for six hours before harvesting mRNA for analysis. The expression of a subset of the tested genes emerged as significantly different in cells treated with Laromustine as compared to control cells. Included among those genes with significantly increased expression were: NTHL1 (17 fold), PARP1 (8 fold), and AGT (5 fold). Included among those genes with significantly decreased expression were: PARP2 (-5 fold) and MSH6 (-74 fold). Increased expression of NTHL1, which encodes for an N-glycosylase that can remove damaged guanine bases, may reduce the effectiveness of Laromustine's alkylation of guanine O6. A strong negative correlation between the level of AGT activity in patient samples and the efficacy of Laromustine has already been established. Some of the gene products identified in this study, such as NTHL1, may emerge as possible cotherapeutic targets or markers for clinical screening. Citation Format: Kristen N. Robinson, Kathryn A. Coe, Justin E. Owumi, Kevin P. Rice. Changes in expression of DNA repair genes in human leukemia cells treated with Laromustine. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5498. doi:10.1158/1538-7445.AM2014-5498
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carbamoylating activity associated with the activation of the antitumor agent Laromustine inhibits angiogenesis by inducing ask1 dependent endothelial cell death
PLOS ONE, 2014Co-Authors: Mei Yang, Kevin P Rice, Dylan J Cincotta, Alexandra Praggastis, Huanjiao Jenny Zhou, Roxanne Ghazvinian, Wang MinAbstract:The anticancer agent 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)-2-[(methylamino)carbonyl]hydrazine (Laromustine), upon decomposition in situ, yields methyl isocyanate and the chloroethylating species 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine (90CE). 90CE has been shown to kill tumor cells via a proposed mechanism that involves interstrand DNA cross-linking. However, the role of methyl isocyanate in the antineoplastic function of Laromustine has not been delineated. Herein, we show that 1,2-bis(methylsulfonyl)-1-[(methylamino)carbonyl]hydrazine (101MDCE), an analog of Laromustine that generates only methyl isocyanate, activates ASK1-JNK/p38 signaling in endothelial cells (EC). We have previously shown that ASK1 forms a complex with reduced thioredoxin (Trx1) in resting EC, and that the Cys residues in ASK1 and Trx1 are critical for their interaction. 101MDCE dissociated ASK1 from Trx1, but not from the phosphoserine-binding inhibitor 14-3-3, in whole cells and in cell lysates, consistent with the known ability of methyl isocyanate to carbamoylate free thiol groups of proteins. 101MDCE had no effect on the kinase activity of purified ASK1, JNK, or the catalytic activity of Trx1. However, 101MDCE, but not 90CE, significantly decreased the activity of Trx reductase-1 (TrxR1). We conclude that methyl isocyanate induces dissociation of ASK1 from Trx1 either directly by carbamoylating the critical Cys groups in the ASK1-Trx1 complex or indirectly by inhibiting TrxR1. Furthermore, 101MDCE (but not 90CE) induced EC death through a non-apoptotic (necroptotic) pathway leading to inhibition of angiogenesis in vitro. Our study has identified methyl isocyanates may contribute to the anticancer activity in part by interfering with tumor angiogenesis.
Francis J Giles - One of the best experts on this subject based on the ideXlab platform.
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phase 3 randomized placebo controlled double blind study of high dose continuous infusion cytarabine alone or with Laromustine vnp40101m in patients with acute myeloid leukemia in first relapse
Blood, 2009Co-Authors: Francis J Giles, Arnaud Pigneux, Daniel J Deangelo, Robert K Stuart, Karen Seiter, Wendy Stock, Darinka Boskovic, Martin S Tallman, Joseph Brandwein, Jonathan KellAbstract:Laromustine is a sulfonylhdrazine alkylator with significant antileukemia activity. An international, randomized (2:1), double-blind, placebo-controlled study was conducted to compare complete remission (CR) rates and overall survival (OS) in patients with first relapse acute myeloid leukemia (AML) treated with Laromustine and high-dose cytarabine (HDAC) versus HDAC/placebo. Patients received 1.5 g/m2 per day cytarabine continuous infusion for 3 days and Laromustine 600 mg/m2 (n 177) or placebo (n 86) on day 2. Patients in CR received consolidation with Laromustine/HDAC or HDAC/ placebo as per initial randomization.After interim analysis at 50% enrollment, the Data Safety Monitoring Board (DSMB) expressed concern that any advantage in CR would be compromised by the observed on-study mortality, and enrollment was held. The CR rate was significantly higher for the Laromustine/HDAC group (35% vs 19%, P .005). However, the 30-day mortality rate and median progression-free survival were significantly worse in this group compared with HDAC/ placebo (11% vs 2%; P .016; 54 days vs 34; P .002). OS and median response durations were similar in both groups. Laromustine/HDAC induced significantly more CR than HDAC/placebo, but OS was not improved due to mortality associated with myelosuppression and its sequelae. The DSMB subsequently approved a revised protocol with Laromustine dose reduction and recombinant growth factor support. The study was registered as NCT00112554 at http://www.clinicaltrials. gov. (Blood. 2009;114:4027-4033)
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clinical activity of Laromustine onrigin in hematologic malignancies
Expert Review of Hematology, 2009Co-Authors: Yesid Alvarado, Ronan T Swords, Kevin R Kelly, Francis J GilesAbstract:Laromustine (Onrigin™), formerly known as Cloretazine® (VNP40101M), belongs to a novel class of alkylating agents – the sulfonylhydrazines – and was selected for clinical development based on its broad anti-tumor activity in preclinical models. Laromustine is metabolized to yield 90CE and methylisocyanate, the former rapidly produces an alkylating, chloroethylating species, similar to the chloroethylating species generated by carmustine. However, several features distinguish Laromustine from carmustine and possibly account for their biological differences in vitro and in vivo. The chloroethylating species responsible for Laromustine’s alkylator effect is relatively specific for guanine and forms a crosslink after incorporation into DNA. Laromustine has significant activity in both older patients with previously untreated acute myeloid leukemia or high-risk myelodysplastic syndrome, including those with very poor-risk disease, and in patients with relapsed disease. Further clinical studies are required wit...
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comorbidity description using the hematopoietic cell transplantation specific comorbidity index hct ci in elderly de novo poor risk aml patients pts treated with Laromustine
Journal of Clinical Oncology, 2009Co-Authors: G J Schiller, Arnaud Pigneux, Daniel J Deangelo, Norbert Vey, Jonathan Kell, Robert K Stuart, Diana Hudak, S M Obrien, Judith E Karp, Francis J GilesAbstract:7050 Background: Treatment of older pts with AML is often complicated by comorbidities and pts with comorbidities are often underrepresented in clinical trials. The HCT-CI, which was developed in pts receiving allogeneic SCT, has been applied to pts receiving induction therapy for AML in an effort to assist in therapeutic and investigational decisions (Kantarjian 2006; Etienne 2007; Giles 2007). HCT-CI scores have been shown to be predictive of early death and survival in pts ≥ 60 years receiving induction therapy for AML, with early death rates of 3%, 11%, and 29% for pts with HCT-CI scores of 0, 1–2, and ≥ 3, respectively (Giles 2007). Methods: 140 pts age ≥ 60 with poor risk de novo AML from two phase II studies were scored for comorbidity by HCT-CI. In these studies, poor risk was defined by the presence of at least one risk factor: age ≥ 70, ECOG PS = 2, unfavorable cytogenetics, or cardiac, pulmonary, or hepatic dysfunction. All pts received induction therapy with 600 mg/m2 Laromustine as a single 3...
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hypermethylation of o6 methylguanine dna methyltransferase mgmt predicts response to Laromustine cloretazine in patients with acute myelogenous leukemia aml or high risk myelodysplastic syndrome mds
Blood, 2008Co-Authors: Ilan Bernstein, Susan Obrien, Norbert Vey, Francis J Giles, Elizabeth Sullivan, Allen S YangAbstract:Laromustine (Cloretazine®) (1,2-bis(methylsulfonyl)-1-(2-chloroethyl)-2-[(methylamino)carbonyl] hydrazine), a sulfonylhydrazine prodrug producing chlorethylating and carbamoylating subspecies, has demonstrated clinical activity in patients with hematologic disorders (Giles et al., J Clin Oncol, 2007). The effect of Laromustine is modulated primarily through the formation of hard chloroethylating electrophiles with preferential alkylating activity for the O6 position of guanine, ultimately resulting in the formation of interstrand cross-links which prevent DNA replication and transcription, leading to cell death. The DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) plays a major role in repairing O6-chloroethylguanine alkylations, critical to the formation of interstrand crosslinks. Epigenetic silencing of the MGMT encoding gene related to DNA hypermethylation has been shown to participate in the pathogenesis of neoplastic disease (Hegi et al., NEJM 2005). Since the alkylating properties of Laromustine target DNA sites normally repaired by MGMT, the absence of the enzyme may represent a unique cellular environment for specific susceptibility to Laromustine (Ishiguro et al., Mol Cancer Ther, 2005). In vitro findings have supported the hypothesis that cellular content of MGMT may predict response. In vivo correlation between clinical response in patients treated with Laromustine and the cellular evidence of epigenetic silencing of the encoding MGMT gene has yet to be demonstrated (Giles et al., Clin Cacner Res, 2004). Our research aimed to determine the DNA methylation status of MGMT isolated from the peripheral blood or bone marrow of patients with AML or high-risk MDS enrolled to a phase II, single-agent study of Laromustine (600 mg/m2 IV over 30 minutes) (Giles et al. J Clin Oncol, 2007). We also aimed to establish a correlation between hypermethylation of MGMT and clinical response to Laromustine. Combined bisulfite restriction analysis (COBRA) was used to determine the MGMT gene methylation status of patients treated with Laromustine. Bone marrow or peripheral blood leukocyte samples from 76 patients enrolled in a phase II, single agent study of Laromustine were coded and blinded to investigators. DNA from each sample was extracted and bisulfite treated. PCR was used to amplify the MGMT CpG Island promoter region (REF/NT_008818.15/Hs10_8975) from 58 patients, prior to methylation specific restriction enzyme digestion. Results were correlated with clinical data of response to Laromustine. The DNA methylation status of MGMT was determined in 58 of the enrolled patients. DNA hypermethylation was found in 3 of the 58 patients (5%). Two of these 3 patients achieved a complete response (CR) (66%), compared to 11 of the 55 patients who achieved a CR, CR with platelet recovery
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a retrospective comparison of matched elderly patients treated with Laromustine cloretazine r or best supportive care or low dose ara c in the lrf aml14 trial abstract
Blood, 2008Co-Authors: Robert Kerrin Hills, Susan Obrien, Verena Karsten, Alan K Burnett, Francis J GilesAbstract:Background : A substantial proportion of older patients with AML are considered unlikely to benefit from an intensive treatment approach. They often receive either best supportive care (BSC), low dose treatment such as Low Dose Ara-C (LDAC), or clinical trials of novel agents. In one of the few randomised studies where patients were prospectively considered likely to be unfit for intensive therapy, LDAC was superior to BSC with 18% v 1% patients achieving CR. No patients with high risk cytogenetics (Grimwade 1998), achieved CR (Burnett 2007). Laromustine (Cloretazine®) is a novel sulfonylhydrazine alkylating agent which preferentially targets the O 6 position of guanine resulting in DNA cross-links. Laromustine has previously shown clinical activity in patients with de novo AML and high risk MDS (Giles et al. JCO 2007). A confirmatory phase II study of single agent Laromustine was conducted in previously untreated patients ≥ 60 years old with de novo AML, prospectively considered likely to be unfit for intensive chemotherapy. Patients had at least one poor risk factor, defined by age ≥70, performance status 2, unfavorable cytogenetics, or cardiac, pulmonary or hepatic dysfunction. Eighty-five patients received induction therapy with 600 mg/m2 Laromustine. Second induction cycles were administered in 14 patients after partial response or hematologic improvement. Eighteen patients received at least one consolidation cycle of cytarabine 400 mg/m2/day CIV for 5 days. Methods: A retrospective non-randomised comparison was performed between the 85 patients treated with Laromustine, and 121 patients satisfying the same entry criteria, treated in the AML 14 trial with either BSC or LDAC. Outcomes were compared using Mantel-Haenszel and logrank methods for unadjusted comparisons, and regression methods for adjusted analyses. Results : Patients in AML14 were slightly older than those treated with Laromustine (median age 75 v 73), and tended to have higher white blood cell counts; by contrast, there were significantly fewer cardiac or respiratory comorbidities reported in the AML14 population. Other important risk factors such as performance status and cytogenetics were similar between the groups. Responses overall (CR/CRp) were seen in 33% (28/85) of patients treated with Laromustine, compared with 2% (1/60) and 23% (14/61) in patients treated with BSC and LDAC (p<0.0001, p=0.2, respectively). In particular, 1 patient with −5/del(5q), and 3 patients with −7/del(7q) cytogenetics experienced a CR with Laromustine; patients in AML 14 with adverse cytogenetics saw no remissions. Survival was significantly improved in the Laromustine group compared to BSC (1 year survival 20% v 8%, unadjusted HR 0.58 [0.40–0.84] p=0.004), and roughly comparable to that of LDAC (1 year survival 20% v 25%, HR 1.04 [0.73–1.49] p=0.8). Analyses adjusted for differences in baseline demographics, and using propensity scores gave consistent figures. Conclusions: Retrospective comparison of unrandomised data has significant limitations even though care has been taken to match for factors known to be predictive for survival. Laromustine was able to achieve a higher CR rate than LDAC or BSC, and produced remissions in groups where no remissions have previously been seen with LDAC or BSC. Laromustine gave significantly better survival than BSC, and demonstrated similar survival to LDAC.
Alan C Sartorelli - One of the best experts on this subject based on the ideXlab platform.
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Influence of Phosphate and Phosphoesters on the Decomposition Pathway of 1,2-Bis(methylsulfonyl)-1-(2-chloroethyhydrazine (90CE), the Active Anticancer Moiety Generated by Laromustine, KS119, and
2016Co-Authors: Philip G Penketh, Kimiko Ishiguro, Raymond P Baumann, Krishnamurthy Shyam, Rui Zhu, Alan C SartorelliAbstract:ABSTRACT: Prodrugs of the short-lived chloroethylating agent 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine (90CE) and i t s methy la t ing ana logue 1,2-b i s-(methylsulfonyl)-1-(methyl)hydrazine (KS90) are potentially useful anticancer agents. This class of agents frequently yields higher ratios of therapeutically active oxophilic electrophiles responsible for DNA O6-guanine alkylations to other electro-philes with lower therapeutic relevance than the nitrosoureas. This results in improved selectivity toward tumors with diminished levels of O6-alkylguanine-DNA alkyltransferase (MGMT), the resistance protein responsible for O6-alkylguanine repair. The formation of O6-(2-chloroethyl)-guanine, which leads to the formation of a DNA−DNA interstrand cross-link, accounts for the bulk of the anticancer activity of 90CE prodrugs. Herein, we describe a new decomposition pathway that is available to 90CE but not to its methylating counterpart. This pathway appears to be subject t
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Influence of Phosphate and Phosphoesters on the Decomposition Pathway of 1,2-Bis(methylsulfonyl)-1-(2-chloroethyhydrazine (90CE), the Active Anticancer Moiety Generated by Laromustine, KS119, and KS119W
2015Co-Authors: Philip G Penketh, Kimiko Ishiguro, Raymond P Baumann, Krishnamurthy Shyam, Rui Zhu, Alan C SartorelliAbstract:Prodrugs of the short-lived chloroethylating agent 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine (90CE) and its methylating analogue 1,2-bis(methylsulfonyl)-1-(methyl)hydrazine (KS90) are potentially useful anticancer agents. This class of agents frequently yields higher ratios of therapeutically active oxophilic electrophiles responsible for DNA O6-guanine alkylations to other electrophiles with lower therapeutic relevance than the nitrosoureas. This results in improved selectivity toward tumors with diminished levels of O6-alkylguanine-DNA alkyltransferase (MGMT), the resistance protein responsible for O6-alkylguanine repair. The formation of O6-(2-chloroethyl)guanine, which leads to the formation of a DNA–DNA interstrand cross-link, accounts for the bulk of the anticancer activity of 90CE prodrugs. Herein, we describe a new decomposition pathway that is available to 90CE but not to its methylating counterpart. This pathway appears to be subject to general/acid base catalysis with phosphate (Pi), phosphomonoesters, and phosphodiesters, being particularly effective. This pathway does not yield a chloroethylating species and results in a major change in nucleophile preference since thiophilic rather than oxophilic electrophiles are produced. Thus, a Pi concentration dependent decrease in DNA–DNA interstand cross-link formation was observed. Changes in 90CE decomposition products but not alkylation kinetics occurred in the presence of Pi since the prebranch point elimination of the N-1 methanesulfinate moiety remained the rate-limiting step. The Pi catalyzed route is expected to dominate at Pi and phosphoester concentrations totaling >25–35 mM. In view of the abundance of Pi and phosphoesters in cells, this pathway may have important effects on agent toxicity, tumor selectivity, and resistance to prodrugs of 90CE. Furthermore, it may be possible to design analogues that diminish this thiophile-generating pathway, which is likely superfluous at best and potentially detrimental to the targeting of hypoxic regions where Pi concentrations can be significantly elevated
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influence of glutathione and glutathione s transferases on dna interstrand cross link formation by 1 2 bis methylsulfonyl 1 2 chloroethyl hydrazine the active anticancer moiety generated by Laromustine
Chemical Research in Toxicology, 2014Co-Authors: Philip G Penketh, Kimiko Ishiguro, Raymond P Baumann, Krishnamurthy Shyam, Rui Zhu, Eric Patridge, Alan C SartorelliAbstract:Prodrugs of 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine (90CE) are promising anticancer agents. The 90CE moiety is a readily latentiated, short-lived (t1/2 ∼ 30 s) chloroethylating agent tha...
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influence of phosphate and phosphoesters on the decomposition pathway of 1 2 bis methylsulfonyl 1 2 chloroethyhydrazine 90ce the active anticancer moiety generated by Laromustine ks119 and ks119w
Chemical Research in Toxicology, 2014Co-Authors: Philip G Penketh, Kimiko Ishiguro, Raymond P Baumann, Krishnamurthy Shyam, Rui Zhu, Alan C SartorelliAbstract:Prodrugs of the short-lived chloroethylating agent 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine (90CE) and its methylating analogue 1,2-bis(methylsulfonyl)-1-(methyl)hydrazine (KS90) are potentially useful anticancer agents. This class of agents frequently yields higher ratios of therapeutically active oxophilic electrophiles responsible for DNA O6-guanine alkylations to other electrophiles with lower therapeutic relevance than the nitrosoureas. This results in improved selectivity toward tumors with diminished levels of O6-alkylguanine-DNA alkyltransferase (MGMT), the resistance protein responsible for O6-alkylguanine repair. The formation of O6-(2-chloroethyl)guanine, which leads to the formation of a DNA–DNA interstrand cross-link, accounts for the bulk of the anticancer activity of 90CE prodrugs. Herein, we describe a new decomposition pathway that is available to 90CE but not to its methylating counterpart. This pathway appears to be subject to general/acid base catalysis with phosphate (Pi), phosphomonoesters, and phosphodiesters, being particularly effective. This pathway does not yield a chloroethylating species and results in a major change in nucleophile preference since thiophilic rather than oxophilic electrophiles are produced. Thus, a Pi concentration dependent decrease in DNA–DNA interstand cross-link formation was observed. Changes in 90CE decomposition products but not alkylation kinetics occurred in the presence of Pi since the prebranch point elimination of the N-1 methanesulfinate moiety remained the rate-limiting step. The Pi catalyzed route is expected to dominate at Pi and phosphoester concentrations totaling >25–35 mM. In view of the abundance of Pi and phosphoesters in cells, this pathway may have important effects on agent toxicity, tumor selectivity, and resistance to prodrugs of 90CE. Furthermore, it may be possible to design analogues that diminish this thiophile-generating pathway, which is likely superfluous at best and potentially detrimental to the targeting of hypoxic regions where Pi concentrations can be significantly elevated.
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preclinical evaluation of Laromustine for use in combination with radiation therapy in the treatment of solid tumors
International Journal of Radiation Biology, 2012Co-Authors: Sara Rockwell, Yanfeng Liu, Helen A Seow, Kimiko Ishiguro, Raymond P Baumann, Philip G Penketh, Krishnamurthy Shyam, Oluwatoyin M Akintujoye, Peter M Glazer, Alan C SartorelliAbstract:Purpose: These studies explored questions related to the potential use of Laromustine in the treatment of solid tumors and in combination with radiotherapy.Materials and methods: The studies used mouse EMT6 cells (both parental and transfected with genes for O6-alkylguanine-DNA transferase [AGT]), repair-deficient human Fanconi Anemia C and Chinese hamster VC8 (BRCA2-/-) cells and corresponding control cells, and EMT6 tumors in mice assayed using cell survival and tumor growth assays.Results: Hypoxia during Laromustine treatment did not protect EMT6 cells or human fibroblasts from this agent. Rapidly proliferating EMT6 cells were more sensitive than quiescent cultures. EMT6 cells expressing mouse or human AGT, which removes O6-alkyl groups from DNA guanine, thereby protecting against G-C crosslink formation, increased resistance to Laromustine. Crosslink-repair-deficient Fanconi Anemia C and VC8 cells were hypersensitive to Laromustine, confirming the importance of crosslinks as lethal lesions. In vitro, ...
Philip G Penketh - One of the best experts on this subject based on the ideXlab platform.
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ph dependent general base catalyzed activation rather than isocyanate liberation may explain the superior anticancer efficacy of Laromustine compared to related 1 2 bis methylsulfonyl 1 2 chloroethyl hydrazine prodrugs
Chemical Biology & Drug Design, 2018Co-Authors: Philip G Penketh, Raymond P Baumann, Richard A Finch, Rachel Sauro, Elena Ratner, Krishnamurthy ShyamAbstract:Laromustine (also known as cloretazine, onrigin, VNP40101M, 101M) is a prodrug of 90CE, a short-lived chloroethylating agent with anticancer activity. The short half-life of 90CE necessitates the use of latentiated prodrug forms for in vivo treatments. Alkylaminocarbonyl based prodrugs such as Laromustine exhibit significantly superior in vivo activity in several murine tumor models compared to analogs utilizing acyl, and alkoxycarbonyl latentiating groups. The alkylaminocarbonyl prodrugs possess two exclusive characteristics: (i) they are primarily unmasked by spontaneous base catalyzed elimination; and (ii) they liberate a reactive carbamoylating species. Previous speculations as to the therapeutic superiority of Laromustine have focused upon the inhibition of enzymes by carbamoylation. We have investigated the therapeutic interactions of analogs with segregated chloroethylating and carbamoylating activities (singly and in combination) in the in vivo murine L1210 leukemia model. The combined treatment with chloroethylating and carbamoylating prodrugs failed to result in any synergism and produced a reduction in the therapeutic efficacy compared to the chloroethylating prodrug alone. Evidence supporting an alternative explanation for the superior tumor selectivity of Laromustine is presented that is centered upon the high pH sensitivity of its base catalyzed activation, and the more alkaline intracellular pH values commonly found within tumor cells. This article is protected by copyright. All rights reserved.
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Influence of Phosphate and Phosphoesters on the Decomposition Pathway of 1,2-Bis(methylsulfonyl)-1-(2-chloroethyhydrazine (90CE), the Active Anticancer Moiety Generated by Laromustine, KS119, and
2016Co-Authors: Philip G Penketh, Kimiko Ishiguro, Raymond P Baumann, Krishnamurthy Shyam, Rui Zhu, Alan C SartorelliAbstract:ABSTRACT: Prodrugs of the short-lived chloroethylating agent 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine (90CE) and i t s methy la t ing ana logue 1,2-b i s-(methylsulfonyl)-1-(methyl)hydrazine (KS90) are potentially useful anticancer agents. This class of agents frequently yields higher ratios of therapeutically active oxophilic electrophiles responsible for DNA O6-guanine alkylations to other electro-philes with lower therapeutic relevance than the nitrosoureas. This results in improved selectivity toward tumors with diminished levels of O6-alkylguanine-DNA alkyltransferase (MGMT), the resistance protein responsible for O6-alkylguanine repair. The formation of O6-(2-chloroethyl)-guanine, which leads to the formation of a DNA−DNA interstrand cross-link, accounts for the bulk of the anticancer activity of 90CE prodrugs. Herein, we describe a new decomposition pathway that is available to 90CE but not to its methylating counterpart. This pathway appears to be subject t
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Influence of Phosphate and Phosphoesters on the Decomposition Pathway of 1,2-Bis(methylsulfonyl)-1-(2-chloroethyhydrazine (90CE), the Active Anticancer Moiety Generated by Laromustine, KS119, and KS119W
2015Co-Authors: Philip G Penketh, Kimiko Ishiguro, Raymond P Baumann, Krishnamurthy Shyam, Rui Zhu, Alan C SartorelliAbstract:Prodrugs of the short-lived chloroethylating agent 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine (90CE) and its methylating analogue 1,2-bis(methylsulfonyl)-1-(methyl)hydrazine (KS90) are potentially useful anticancer agents. This class of agents frequently yields higher ratios of therapeutically active oxophilic electrophiles responsible for DNA O6-guanine alkylations to other electrophiles with lower therapeutic relevance than the nitrosoureas. This results in improved selectivity toward tumors with diminished levels of O6-alkylguanine-DNA alkyltransferase (MGMT), the resistance protein responsible for O6-alkylguanine repair. The formation of O6-(2-chloroethyl)guanine, which leads to the formation of a DNA–DNA interstrand cross-link, accounts for the bulk of the anticancer activity of 90CE prodrugs. Herein, we describe a new decomposition pathway that is available to 90CE but not to its methylating counterpart. This pathway appears to be subject to general/acid base catalysis with phosphate (Pi), phosphomonoesters, and phosphodiesters, being particularly effective. This pathway does not yield a chloroethylating species and results in a major change in nucleophile preference since thiophilic rather than oxophilic electrophiles are produced. Thus, a Pi concentration dependent decrease in DNA–DNA interstand cross-link formation was observed. Changes in 90CE decomposition products but not alkylation kinetics occurred in the presence of Pi since the prebranch point elimination of the N-1 methanesulfinate moiety remained the rate-limiting step. The Pi catalyzed route is expected to dominate at Pi and phosphoester concentrations totaling >25–35 mM. In view of the abundance of Pi and phosphoesters in cells, this pathway may have important effects on agent toxicity, tumor selectivity, and resistance to prodrugs of 90CE. Furthermore, it may be possible to design analogues that diminish this thiophile-generating pathway, which is likely superfluous at best and potentially detrimental to the targeting of hypoxic regions where Pi concentrations can be significantly elevated
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influence of glutathione and glutathione s transferases on dna interstrand cross link formation by 1 2 bis methylsulfonyl 1 2 chloroethyl hydrazine the active anticancer moiety generated by Laromustine
Chemical Research in Toxicology, 2014Co-Authors: Philip G Penketh, Kimiko Ishiguro, Raymond P Baumann, Krishnamurthy Shyam, Rui Zhu, Eric Patridge, Alan C SartorelliAbstract:Prodrugs of 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine (90CE) are promising anticancer agents. The 90CE moiety is a readily latentiated, short-lived (t1/2 ∼ 30 s) chloroethylating agent tha...
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influence of phosphate and phosphoesters on the decomposition pathway of 1 2 bis methylsulfonyl 1 2 chloroethyhydrazine 90ce the active anticancer moiety generated by Laromustine ks119 and ks119w
Chemical Research in Toxicology, 2014Co-Authors: Philip G Penketh, Kimiko Ishiguro, Raymond P Baumann, Krishnamurthy Shyam, Rui Zhu, Alan C SartorelliAbstract:Prodrugs of the short-lived chloroethylating agent 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine (90CE) and its methylating analogue 1,2-bis(methylsulfonyl)-1-(methyl)hydrazine (KS90) are potentially useful anticancer agents. This class of agents frequently yields higher ratios of therapeutically active oxophilic electrophiles responsible for DNA O6-guanine alkylations to other electrophiles with lower therapeutic relevance than the nitrosoureas. This results in improved selectivity toward tumors with diminished levels of O6-alkylguanine-DNA alkyltransferase (MGMT), the resistance protein responsible for O6-alkylguanine repair. The formation of O6-(2-chloroethyl)guanine, which leads to the formation of a DNA–DNA interstrand cross-link, accounts for the bulk of the anticancer activity of 90CE prodrugs. Herein, we describe a new decomposition pathway that is available to 90CE but not to its methylating counterpart. This pathway appears to be subject to general/acid base catalysis with phosphate (Pi), phosphomonoesters, and phosphodiesters, being particularly effective. This pathway does not yield a chloroethylating species and results in a major change in nucleophile preference since thiophilic rather than oxophilic electrophiles are produced. Thus, a Pi concentration dependent decrease in DNA–DNA interstand cross-link formation was observed. Changes in 90CE decomposition products but not alkylation kinetics occurred in the presence of Pi since the prebranch point elimination of the N-1 methanesulfinate moiety remained the rate-limiting step. The Pi catalyzed route is expected to dominate at Pi and phosphoester concentrations totaling >25–35 mM. In view of the abundance of Pi and phosphoesters in cells, this pathway may have important effects on agent toxicity, tumor selectivity, and resistance to prodrugs of 90CE. Furthermore, it may be possible to design analogues that diminish this thiophile-generating pathway, which is likely superfluous at best and potentially detrimental to the targeting of hypoxic regions where Pi concentrations can be significantly elevated.
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phase i study of temozolomide and Laromustine vnp40101m in patients with relapsed or refractory leukemia
Clinical Lymphoma Myeloma & Leukemia, 2010Co-Authors: David A Rizzieri, Verena Karsten, Ann Cahill, Samantha Lorusso, William Tse, Khuda Khan, Anjali S Advani, Joseph O Moore, Stanton L GersonAbstract:Abstract Purpose Although alkylators are known to be effective against some myeloid leukemias, resistance is often mediated via O 6 -alkylguanine-DNA alkyltransferase (AGT). Temozolomide's inhibition of AGT may sensitize leukemia cells to the novel alkylator Laromustine. We conducted a phase I translational study to evaluate the toxicities and estimate the maximum tolerated dose (MTD) of Laromustine when administered with temozolomide (TMZ) in patients with hematologic malignancies. Patients and Methods TMZ was delivered twice daily for 5 doses followed by a single infusion of Laromustine. The target TMZ dose was the dose that would reliably result in > 90% AGT depletion. Once the target TMZ dose was identified, the Laromustine dose was escalated. A total of 35 patients with relapsed/refractory leukemia were treated. Results Treatment with TMZ 300 mg for 5 doses resulted in > 90% depletion of AGT levels in 5 of 6 patients. The MTD of the combination was established at TMZ 1500 mg and Laromustine 300 mg/m 2 . Three of the 7 patients assayed from cohort 1 achieved > 90% depletion of AGT activity (range, 77%-100% depletion; median, 88%). Five of 6 patients enrolled in cohort 2 achieved > 90% depletion of AGT activity (range, 92%-100% depletion; median, 93.5%). This established that the 300-mg dose of TMZ (1500 mg total) would be maintained in subsequent cohorts. The majority of adverse events were primarily hematologic, with infectious and pulmonary complications also noted. Three (9%) of the patients with previous refractory disease achieved a complete remission, and 5 (14%) of the patients achieved a morphologic, leukemia-free, but persistent hypocellular bone marrow status. Conclusion Laromustine in combination with TMZ is tolerable and manageable at doses that predictably suppress AGT. Reliable TMZ-induced inhibition of AGT was observed in doses that are clinically tolerable. Evidence of antitumor effect was observed with this combination, suggesting that further efficacy studies should be performed.
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single agent Laromustine a novel alkylating agent has significant activity in older patients with previously untreated poor risk acute myeloid leukemia
Journal of Clinical Oncology, 2010Co-Authors: G J Schiller, Susan Obrien, Arnaud Pigneux, Daniel J Deangelo, Norbert Vey, Jonathan Kell, Scott D Solomon, Robert K Stuart, Verena Karsten, Ann CahillAbstract:Purpose An international phase II study of Laromustine (VNP40101M), a sulfonylhydrazine alkylating agent, was conducted in patients age 60 years or older with previously untreated poor-risk acute myeloid leukemia (AML). Patients and Methods Laromustine 600 mg/m2 was administered as a single 60-minute intravenous infusion. Patients were age 70 years or older or 60 years or older with at least one additional risk factor—unfavorable AML karyotype, Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 2, and/or cardiac, pulmonary, or hepatic comorbidities. Results Eighty-five patients (median age, 72 years; range, 60 to 87 years) were treated. Poor-risk features included age 70 years or older, 78%; adverse karyotype, 47%; PS of 2, 41%; pulmonary disease, 77%; cardiac disease, 73%; and hepatic disease, 3%. Ninety-six percent of patients had at least two risk factors, and 39% had at least four risk factors. The overall response rate (ORR) was 32%, with 20 patients (23%) achieving complete respons...
