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Eric O. Aboagye - One of the best experts on this subject based on the ideXlab platform.
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abstract p5 01 02 evaluation of apoptosis in breast cancer using the novel pet probe 18f ICMT 11 in patients treated with neoadjuvant fec chemotherapy initial assessment of optimum imaging time and relation to caspase 3 immunostaining
Cancer Research, 2015Co-Authors: Shairoz Merchant, Eric O. Aboagye, Kasia Kozlowski, Adrian Lim, Naina Patel, Jennifer H Steel, Susan Cleator, Sami Shousha, Vidhya Varghese, Raoul Charles CoombesAbstract:Background: [18F]ICMT-11 is an isatin analogue which has been developed by our group as a novel PET radiotracer for studies of apoptosis in vivo. Preclinical studies have demonstrated subnanomolar affinity to caspase 3, and validated the potential for imaging apoptosis in xenograft models. A first-in-man study showed that the agent was well tolerated with acceptable dosimetry. This is the first study of this agent to measure the effect of chemotherapy on radiotracer uptake in patients. As apoptosis is a dynamic process, one of the main objectives of the study was to determine the optimal time-point for imaging post-chemotherapy and compare the results with immunohistochemistry assessments at the same time-points. The study was approved by a regional ethics committee and ARSAC. Methods: 7 patients with breast tumour lesions measuring 15mm or more, due to undergo neoadjuvant chemotherapy with FEC (5FU, Epirubicin, Cyclophosphamide) had dynamic PET scans for 66mins 30seconds following intravenous injection of [18F]ICMT-11 with a mean activity of 340.82 Mbq±20.76 and Specific Activity range of 447.014-5128.34 Gbq/µmol prior to chemotherapy and 24h-2 weeks post-chemotherapy. A breast biopsy was also obtained within a few hours of the 2nd PET scan to correlate apoptosis in the breast tissue utilising TUNEL and Caspase 3 staining by immunohistochemistry. Volumes of interest were drawn manually and analyzed using Analyze software®. Results: The scans were well tolerated in all patients. Uptake of [18F]ICMT-11 was demonstrated in all tumor lesions. The tumours studied included ER positive and PR positive, HER2 positive and triple negative patients. The first cohort patients were imaged pre-chemotherapy and 24-48h post chemotherapy. Tumour to Breast ratio (TBR) showed an increase from 1.42±0.21(pre) to 1.71±0.33 (post). Tumour to muscle ratio (TMR) was not increased, 1.52±0.30(pre) and 1.22±0.09 (post). In addition, an increase the SUV was noted in the lymph nodes of patients, at both 24 and 48h. (SUVav 0.39±0.02 (pre), 0.45±0.03 (post), and SUVmax 0.87± 0.02(pre) ,1.22±0.12 (post). The lymph nodes were however not sampled for immunohistochemistry. A further cohort of patients had the follow-up scan 2 weeks post chemotherapy, TBR and TMR were both increased in this cohort 1.50±0.22 (pre), 2.52±0.48 (post),and 1.82±0.10 (pre), 2.08±0.0.04 (post), respectively. Caspase and TUNEL labelling with immunohistochemistry also showed increased in apoptosis in the breast biopsies at 2 weeks compared to baseline in keeping with the PET data. Conclusion: These preliminary data suggest that [18F]ICMT-11 is a promising marker for chemotherapy induced apoptosis in vivo, and correlates with findings in tumor biospsies using TUNEL and immunostaining for caspase 3. Further work is underway to study a larger cohort of patients, and identify the optimal PET pharmacokinetic parameter to describe [18F]ICMT-11 uptake and retention. Citation Format: Shairoz Merchant, Eric O Aboagye, Adrian Lim, Kasia Kozlowski, Naina Patel, Jennifer Steel, Susan Cleator, Sami Shousha, Vidhya Varghese, Raoul C Coombes, Laura Kenny. Evaluation of apoptosis in breast cancer using the novel PET probe [18F]ICMT-11 in patients treated with neoadjuvant FEC chemotherapy: Initial assessment of optimum imaging time and relation to caspase-3 immunostaining [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P5-01-02.
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preclinical assessment of carboplatin treatment efficacy in lung cancer by 18f ICMT 11 positron emission tomography
PLOS ONE, 2014Co-Authors: Timothy H. Witney, Robin Fortt, Eric O. AboagyeAbstract:Tumour response to therapy is assessed primarily in the clinic by monitoring reductions in tumour size. However, this approach lacks sensitivity since in many cases several weeks may elapse before there is evidence of tumour shrinkage. There is therefore a need to develop non-invasive imaging techniques for monitoring tumour treatment response in the clinic. Here, we assessed the pre-clinical utility of 18F-ICMT-11 positron emission tomography - a method for detecting caspase 3/7 activation - in non-small cell lung cancer (NSCLC). 18F-ICMT-11 uptake was compared to molecular biochemical measures of cell death in PC9 and A549 NSCLC cells following treatment with carboplatin in vitro and in vivo. Carboplatin-induced apoptosis in the ERCC1 low/mutant EGFR PC9 cells was characterised by time and dose-related increased caspase-3/7 activation, poly-ADP-ribose polymerase cleavage and Annexin V staining. 18F-ICMT-11 uptake was consequently increased up to 14-fold at 200 µM carboplatin compared to vehicle treated cells (P<0.01). In contrast, necrosis was the predominant death mechanism in ERCC1 high/wt EGFR A549 cells and no change in 18F-ICMT-11 uptake was detected. In vivo, histological analysis of PC9 tumour xenografts indicated high pre-therapy necrosis. A 4.6-fold increase in cleaved caspase-3/7 was measured in non-necrotic regions of PC9 tumours at 48h post carboplatin therapy. Average PET-derived tumour 18F-ICMT-11 uptake was insensitive to changes in apoptosis in the presence of substantial pre-existing necrosis. PET-based voxel intensity sorting however, identified intra-tumoural regions of high 18F-ICMT-11 uptake, enabling accurate assessment of apoptosis and therefore therapy response. In A549 tumours that lacked high pre-therapy necrosis, carboplatin induced growth inhibition that was only minimally associated with apoptosis and thus not detectable by 18F-ICMT-11 PET.
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18F-ICMT-11 cell uptake correlates to dose-dependent increases in caspase 3 activity following carboplatin treatment.
2014Co-Authors: Timothy H. Witney, Robin R. Fortt, Eric O. AboagyeAbstract:A: Chemical structure of 18F-ICMT-11. B: Dose-dependent changes in caspase 3/7 activity following carboplatin treatment. C: Dose-dependent changes in 18F-ICMT-11 uptake in cells following carboplatin treatment. D: Correlation between caspase 3 activity and 18F-ICMT-11 uptake in PC9 cells.
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Aboagye, “Preclinical assessment of carboplatin treatment efficacy in lung cancer by 18F-ICMT-11-positron emission tomography
2014Co-Authors: Timothy H. Witney, Robin R. Fortt, Eric O. AboagyeAbstract:Tumour response to therapy is assessed primarily in the clinic by monitoring reductions in tumour size. However, this approach lacks sensitivity since in many cases several weeks may elapse before there is evidence of tumour shrinkage. There is therefore a need to develop non-invasive imaging techniques for monitoring tumour treatment response in the clinic. Here, we assessed the pre-clinical utility of 18F-ICMT-11 positron emission tomography- a method for detecting caspase 3/7 activation- in non-small cell lung cancer (NSCLC). 18F-ICMT-11 uptake was compared to molecular biochemical measures of cell death in PC9 and A549 NSCLC cells following treatment with carboplatin in vitro and in vivo. Carboplatin-induced apoptosis in the ERCC1 low/mutant EGFR PC9 cells was characterised by time and dose-related increased caspase-3/7 activation, poly-ADP-ribose polymerase cleavage and Annexin V staining. 18F-ICMT-11 uptake was consequently increased up to 14-fold at 200 mM carboplatin compared to vehicle treated cells (P,0.01). In contrast, necrosis was the predominant death mechanism in ERCC1 high/wt EGFR A549 cells and no change in 18F-ICMT-11 uptake was detected. In vivo, histological analysis of PC9 tumour xenografts indicated high pre-therapy necrosis. A 4.6-fold increase in cleaved caspase-3/7 was measured in non-necrotic regions of PC9 tumours at 48h post carboplatin therapy. Average PET-derived tumour 18F-ICMT-11 uptake was insensitive to changes in apoptosis in the presence of substantial pre-existing necrosis. PET-based voxel intensity sorting however, identified intra-tumoural regions of high 18F-ICMT-11 uptake, enabling accurate assessment o
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Temporal changes in cell death markers and 18F-ICMT-11 uptake after carboplatin treatment.
2014Co-Authors: Timothy H. Witney, Robin R. Fortt, Eric O. AboagyeAbstract:A: Time course of changes in caspase 3/7 activity following carboplatin treatment. B: Western blot analysis of the levels of uncleaved PARP, cleaved PARP and cleaved (active) caspase 3 post 50 µM carboplatin treatment (0–96 h) in PC9 (i) and A549 cells (ii). C: Temporal changes in 18F-ICMT-11 uptake in cells following carboplatin treatment. D: Correlation between caspase 3 activity and 18F-ICMT-11 uptake in PC9 cells.
Graham Smith - One of the best experts on this subject based on the ideXlab platform.
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development of 18f ICMT 11 for imaging caspase 3 7 activity during therapy induced apoptosis
Cancers, 2020Co-Authors: Segundo Francisco Garciaarguello, Beatriz Lopezlorenzo, Bart Cornelissen, Graham SmithAbstract:Insufficient apoptosis is a recognised hallmark of cancer. A strategy to quantitatively measure apoptosis in vivo would be of immense value in both drug discovery and routine patient management. The first irreversible step in the apoptosis cascade is activation of the “executioner” caspase-3 enzyme to commence cleavage of key structural proteins. One strategy to measure caspase-3 activity is Positron Emission Tomography using isatin-5-sulfonamide radiotracers. One such radiotracer is [18F]ICMT-11, which has progressed to clinical application. This review summarises the design and development process for [18F]ICMT-11, suggesting potential avenues for further innovation.
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automated gmp synthesis of 18f ICMT 11 for in vivo imaging of caspase 3 activity
Nuclear Medicine and Biology, 2012Co-Authors: Robin Fortt, Graham Smith, Ramla O Awais, S K Luthra, Eric O. AboagyeAbstract:Abstract Introduction Isatin-5-sulfonamide ([ 18 F]ICMT-11) is a sub-nanomolar inhibitor of caspase-3 previously evaluated as an apoptosis imaging agent. Herein, an alternative radiosynthesis of [ 18 F]ICMT-11 with increased purity and specific activity is presented. Finally, a GMP-applicable automated radiosynthesis of [ 18 F]ICMT-11 is described. Methods The preparation of [ 18 F]ICMT-11 was evaluated under a variety of reaction conditions, including reaction solvent, by employing alternative phase transfer catalysts and under different deprotection conditions. Following initial investigations, the process was transferred onto a fully automated GE FASTlab synthesis platform for further development and optimisation. Results The synthesis of [ 18 F]ICMT-11 was successfully validated under GMP conditions, resulting in a yield of 4.6 ± 0.4 GBq with a radiochemical purity of > 98% at EOS and a specific activity of 685 ± 237 GBq/μmol within 90 min. Quality control was carried out in accordance with the European Pharmacopoeia and demonstrated that [ 18 F]ICMT-11 can be consistently manufactured on the FASTlab to meet specifications. Conclusions A simplified methodology for the synthesis of the apoptosis imaging agent, [ 18 F]ICMT-11, has been achieved by the S N 2 displacement of a tosylate leaving group with [ 18 F]fluoride ion. This results in an increased purity and specific activity over the original copper catalysed “Click” synthetic stratagem reaction involving 2-[ 18 F]fluoroethylazide with an alkyne precursor and is now suitable for routine clinical application.
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imaging apoptosis with positron emission tomography bench to bedside development of the caspase 3 7 specific radiotracer 18 f ICMT 11
European Journal of Cancer, 2012Co-Authors: Quangde Nguyen, Graham Smith, Robin Fortt, Amarnath Challapalli, Eric O. AboagyeAbstract:The capacity to evade apoptosis has been defined as one of the hallmarks of cancer and, thus, effective anti-cancer therapy often induces apoptosis. A biomarker for imaging apoptosis could assist in monitoring the efficacy of a wide range of current and future therapeutics. Despite the potential, there are limited clinical examples of the use of positron emission tomography for imaging of apoptosis. [(18)F]ICMT-11 is a novel reagent designed to non-invasively image caspase-3 activation and, hence, drug-induced apoptosis. Radiochemistry development of [(18)F]ICMT-11 has been undertaken to improve specific radioactivity, reduce content of stable impurities, reduce synthesis time and enable automation for manufacture of multi-patient dose. Due to the promising mechanistic and safety profile of [(18)F]ICMT-11, the radiotracer is transitioning to clinical development and has been selected as a candidate radiotracer by the QuIC-ConCePT consortium for further evaluation in preclinical models and humans. A successful outcome will allow use of the radiotracer as qualified method for evaluating the pharmaceutical industry's next generation therapeutics.
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abstract a222 assessment of tumor response to therapy with the caspase 3 7 specific 18f ICMT 11 pet imaging tracer
Molecular Cancer Therapeutics, 2009Co-Authors: Quangde Nguyen, Matthias Glaser, Meg Perumal, Graham Smith, Edward G Robins, Eric O. AboagyeAbstract:Of the molecular biochemical alterations that occur during apoptosis, activation of caspases, notably caspase‐3, is probably the most attractive for developing specific in vivo molecular imaging probes. We recently designed a library of isatin‐5 sulfonamides and selected [18F]ICMT‐11 for further evaluation on the basis of sub‐nanomolar affinity for activated capsase‐3, high metabolic stability, and facile radiolabeling. We have demonstrated that [18F]ICMT‐11 binds to a range of drug‐induced apoptotic cancer cells in vitro and to 38C13 murine lymphoma xenografts in vivo by up to 2‐fold at 24 h post‐treatment compared to vehicle treatment. We further associated the increased signal intensity in tumors after drug treatment ‐ detected by whole body in vivo microPET imaging ‐ with increased apoptosis detected by immunohistochemistry, and have therefore characterized [18F]ICMT‐11 as a caspase‐3/7 specific PET imaging radiotracer for the assessment of tumor apoptosis that could find utility in anticancer drug development and the monitoring of early responses to therapy. In the present study, we have investigated the sensitivity of [18F]ICMT‐11 compared to [18F]DG in a longitudinal experimental protocol where the same tumor bearing mouse is subjected to pre‐ ,24h and 48h post‐cyclophosphamide treatment microPET imaging. The tumor volumes have been recorded throughout the study for comparison with PET generated data. [18F]ICMT‐11 PET images and imaging variables were characterized by a weak baseline tumor uptake in pretreated animals, which increased after 24h cyclophosphamide treatment, then decreased at 48h posttreatment to levels greater than that of baseline (NUV60 = 0.05±0.01, 0.12±0.03 and 0.09±0.03 at pre‐, 24h and 48h post‐treatment, respectively). In contrast, [18F]DG PET images and imaging variables showed a high tumor uptake in pretreated animals, as expected, that decreased progressively at 24 and 48h posttreatment (NUV60=3.33±0.24, 1.95±0.16 and 1.26±0.10 at pre‐, 24h and 48h post‐treatment, respectively). The changes in [18F]ICMT‐11 and [18F]DG uptake occurred in parallel with small reduction (94.3%±6.0 that of the pretreated mice tumor volumes) of the tumor volume at 24h posttreatment compared to pretreatment, and a more drastic shrinkage (29.9%±3.6 that of the pretreated mice tumor volumes) at 48h posttreatment. We showed that both [18F]ICMT‐11 and [18F]DG PET can be use to monitor response to cyclophosphamide treatment in our longitudinal experimental model. At 24h and 48h posttreatment, [18F]ICMT‐11 PET imaging detects increased tumor apoptosis and [18F]DG PET detects decreased tumor metabolic activity. At 24h posttreatment, the increased [18F]ICMT‐11 and decreased [18F]DG PET tumor intensity signals are associated with only a small decrease in tumor volumes. In contrast, we observed a drastic tumor shrinkage at 48h posttreatment that was, however, associated with less tumor apoptosis detected by [18F]ICMT‐11 and almost no tumor metabolic activity. It is possible that the early increase in tumor apoptosis (24 h) led to tumor shrinkage. Our future studies will investigate [18F]ICMT‐11 PET imaging assessment of tumor response to therapy using a specific apoptosis targeting drug in the same longitudinal experimental model. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A222.
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positron emission tomography imaging of drug induced tumor apoptosis with a caspase 3 7 specific 18f labeled isatin sulfonamide
Proceedings of the National Academy of Sciences of the United States of America, 2009Co-Authors: Quangde Nguyen, Matthias Glaser, Meg Perumal, Erik Arstad, Graham Smith, Eric O. AboagyeAbstract:Of the molecular biochemical alterations that occur during apoptosis, activation of caspases, notably caspase-3, is probably the most attractive for developing specific in vivo molecular imaging probes. We recently designed a library of isatin-5 sulfonamides and selected [18F]ICMT-11 for further evaluation on the basis of subnanomolar affinity for activated capsase-3, high metabolic stability, and facile radiolabeling. In this present study, we have demonstrated that [18F]ICMT-11 binds to a range of drug-induced apoptotic cancer cells in vitro and to 38C13 murine lymphoma xenografts in vivo by up to 2-fold at 24 h posttreatment compared to vehicle treatment. We further demonstrated that the increased signal intensity in tumors after drug treatment, detected by whole body in vivo microPET imaging, was associated with increased apoptosis. In summary, we have characterized [18F]ICMT-11 as a caspase-3/7 specific PET imaging radiotracer for the assessment of tumor apoptosis that could find utility in anticancer drug development and the monitoring of early responses to therapy.
Patrick J Casey - One of the best experts on this subject based on the ideXlab platform.
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abstract 2339 targeting ICMT in pancreatic cancer
Cancer Research, 2018Co-Authors: Kanjoormana Aryan Manu, Patrick J Casey, Tin Fan Chai, Jing T Teh, Wan Zhu, Mei WangAbstract:Introduction: Pancreatic Cancer remains one of the most difficult to treat human cancers with the 5-year survival as low as 5%. No targeted therapy yet developed against Pancreatic cancer. Here we want to target Isoprenylcysteine carboxylmethyltransferase (ICMT), an enzyme that post translationally modifies a group of proteins including several small GTPases against Pancreatic Cancer. Method: ICMT inhibition was achieved using lentivirus expressing ICMT shRNA and a pharmacological inhibitor named Cysmethynil. We evaluated a panel of human pancreatic cancer cell lines and identified those that are sensitive to ICMT inhibition by cell viability assay. This responsiveness to ICMT inhibition was confirmed in in vivo xenograft tumor mouse models using both Cysmethynil and shRNA-targeting ICMT. Flow cytometry analysis after DAPI or PI staining is used to detect cell cycle arrest and apoptosis. We used western blot analysis to study autophagy, apoptosis and cell cycle markers. ShRNA for P21 is used for p21 knock down studies. SiRNA for p53 is used to study whether p21 induction is p53 dependent. BNIP3, ULK1 and ATG5 knock down was done using specific shRNAs to study their role in ICMT inhibition induced autophagy and apoptosis. BCL-xL is over expressed in the cells using retroviral vectors to study the role of apoptosis in ICMT inhibition induced cell death. Cell and mitochondrial respiration was determined by oxygen consumption rate analysis using Seahorse XF24 analyzer. Summary: In sensitive pancreatic cancer cells, ICMT inhibition induces mitochondrial respiratory deficiency and cellular energy depletion, leading to significant upregulation of p21 and p21 dependent induction of BNIP3 leading to autophagy and apoptosis. But unlike in prostate and liver cancer, ICMT inhibition induced apoptosis not the autophagy responsible for inhibition of cell viability in pancreatic cancer. Conclusion: These findings suggest ICMT is a potential therapeutic target against pancreatic cancers and atleast in pancreatic cancer, ICMT inhibition induced apoptosis but not autophagy responsible for its therapeutic efficacy. Citation Format: Kanjoormana A. Manu, Tin F. Chai, Jing T. Teh, Wan Zhu, Patrick J. Casey, Mei Wang. Targeting ICMT in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2339.
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inhibition of isoprenylcysteine carboxylmethyltransferase induces cell cycle arrest and apoptosis through p21 and p21 regulated bnip3 induction in pancreatic cancer
Molecular Cancer Therapeutics, 2017Co-Authors: Kanjoormana Aryan Manu, Jing Tsong Teh, Wan Long Zhu, Patrick J Casey, Tin Fan Chai, Mei WangAbstract:Pancreatic cancer remains one of the most difficult to treat human cancers despite recent advances in targeted therapy. Inhibition of isoprenylcysteine carboxylmethyltransferase (ICMT), an enzyme that posttranslationally modifies a group of proteins including several small GTPases, suppresses proliferation of some human cancer cells. However, the efficacy of ICMT inhibition on human pancreatic cancer has not been evaluated. In this study, we have evaluated a panel of human pancreatic cancer cell lines and identified those that are sensitive to ICMT inhibition. In these cells, ICMT suppression inhibited proliferation and induced apoptosis. This responsiveness to ICMT inhibition was confirmed in in vivo xenograft tumor mouse models using both a small-molecule inhibitor and shRNA-targeting ICMT. Mechanistically, we found that, in sensitive pancreatic cancer cells, ICMT inhibition induced mitochondrial respiratory deficiency and cellular energy depletion, leading to significant upregulation of p21. Furthermore, we characterized the role of p21 as a regulator and coordinator of cell signaling that responds to cell energy depletion. Apoptosis, but not autophagy, that is induced via p21-activated BNIP3 expression accounts for the efficacy of ICMT inhibition in sensitive pancreatic cancer cells in both in vitro and in vivo models. In contrast, cells resistant to ICMT inhibition demonstrated no mitochondria dysfunction or p21 signaling changes under ICMT suppression. These findings not only identify pancreatic cancers as potential therapeutic targets for ICMT suppression but also provide an avenue for identifying those subtypes that would be most responsive to agents targeting this critical enzyme. Mol Cancer Ther; 16(5); 914-23. ©2017 AACR.
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isoprenylcysteine carboxylmethyltransferase regulates mitochondrial respiration and cancer cell metabolism
Oncogene, 2015Co-Authors: Jing Tsong Teh, Wan Long Zhu, Olga Ilkayeva, Jessica R Gooding, Patrick J Casey, Scott A Summers, Christopher B Newgard, Mei WangAbstract:Isoprenylcysteine carboxylmethyltransferase (ICMT) catalyzes the last of the three-step posttranslational protein prenylation process for the so-called CaaX proteins, which includes many signaling proteins, such as most small GTPases. Despite extensive studies on ICMT and its regulation of cell functions, the mechanisms of much of the impact of ICMT on cellular functions remain unclear. Our recent studies demonstrated that suppression of ICMT results in induction of autophagy, inhibition of cell growth and inhibition of proliferation in various cancer cell types, prompting this investigation of potential metabolic regulation by ICMT. We report here the findings that ICMT inhibition reduces the function of mitochondrial oxidative phosphorylation in multiple cancer cell lines. In-depth oximetry analysis demonstrated that functions of mitochondrial complex I, II and III are subject to ICMT regulation. Consistently, ICMT inhibition decreased cellular ATP and depleted critical tricarboxylic acid cycle metabolites, leading to suppression of cell anabolism and growth, and marked autophagy. Several different approaches demonstrated that the impact of ICMT inhibition on cell proliferation and viability was largely mediated by its effect on mitochondrial respiration. This previously unappreciated function of ICMT, which can be therapeutically exploited, likely has a significant role in the impact of ICMT on tumorigenic processes.
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functionalized indoleamines as potent drug like inhibitors of isoprenylcysteine carboxyl methyltransferase ICMT
European Journal of Medicinal Chemistry, 2013Co-Authors: Pondy Murugappan Ramanujulu, Patrick J Casey, Tianming Yang, Siew Qi Yap, Fuichung Wong, Mei WangAbstract:The enzyme isoprenylcysteine carboxyl methyltransferase (ICMT) plays an important role in the post-translational modification of proteins involved in the regulation of cell growth and oncogenesis. The biological consequences of ICMT inhibition strongly implicate the enzyme as a potential therapeutic target for cancer and provide a compelling rationale for developing specific ICMT inhibitors as anti-cancer agents. We report here the systematic modification of the known ICMT inhibitor cysmethynil to give an analog 15 with greatly improved solubility and PAMPA permeability which was achieved with concurrent gains in ICMT inhibitory and cell-based antiproliferative activities. The modifications involved replacing the amide side chain of cysmethynil with a tertiary amine, and introducing an aminopyrimidine ring in place of m-tolyl. The presence of the weakly basic and polar aminopyrimidine ring contributed significantly to the potency and drug-like profile of the final compound.
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a small molecule inhibitor of isoprenylcysteine carboxymethyltransferase induces autophagic cell death in pc3 prostate cancer cells
Journal of Biological Chemistry, 2008Co-Authors: Mei Wang, Wanloo Tan, Jin Zhou, Jolene Leow, H S Lee, Patrick J CaseyAbstract:A number of proteins involved in cell growth control, including members of the Ras family of GTPases, are modified at their C terminus by a three-step posttranslational process termed prenylation. The enzyme isoprenylcysteine carboxylmethyl-transferase (ICMT) catalyzes the last step in this process, and genetic and pharmacological suppression of ICMT activity significantly impacts on cell growth and oncogenesis. Screening of a diverse chemical library led to the identification of a specific small molecule inhibitor of ICMT, cysmethynil, that inhibited growth factor signaling and tumorigenesis in an in vitro cancer cell model (Winter-Vann, A. M., Baron, R. A., Wong, W., dela Cruz, J., York, J. D., Gooden, D. M., Bergo, M. O., Young, S. G., Toone, E. J., and Casey, P. J. (2005) Proc. Natl. Acad. Sci. U. S. A. 102, 4336-4341). To further evaluate the mechanisms through which this ICMT inhibitor impacts on cancer cells, we developed both in vitro and in vivo models utilizing PC3 prostate cancer cells. Treatment of these cells with cysmethynil resulted in both an accumulation of cells in the G(1) phase and cell death. Treatment of mice harboring PC3 cell-derived xenograft tumors with cysmethynil resulted in markedly reduced tumor size. Analysis of cell death pathways unexpectedly showed minimal impact of cysmethynil treatment on apoptosis; rather, drug treatment significantly enhanced autophagy and autophagic cell death. Cysmethynil-treated cells displayed reduced mammalian target of rapamycin (mTOR) signaling, providing a potential mechanism for the excessive autophagy as well as G(1) cell cycle arrest observed. These results identify a novel mechanism for the antitumor activity of ICMT inhibition. Further, the dual effects of cell death and cell cycle arrest by cysmethynil treatment strengthen the rationale for targeting ICMT in cancer chemotherapy.
Mei Wang - One of the best experts on this subject based on the ideXlab platform.
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abstract 2339 targeting ICMT in pancreatic cancer
Cancer Research, 2018Co-Authors: Kanjoormana Aryan Manu, Patrick J Casey, Tin Fan Chai, Jing T Teh, Wan Zhu, Mei WangAbstract:Introduction: Pancreatic Cancer remains one of the most difficult to treat human cancers with the 5-year survival as low as 5%. No targeted therapy yet developed against Pancreatic cancer. Here we want to target Isoprenylcysteine carboxylmethyltransferase (ICMT), an enzyme that post translationally modifies a group of proteins including several small GTPases against Pancreatic Cancer. Method: ICMT inhibition was achieved using lentivirus expressing ICMT shRNA and a pharmacological inhibitor named Cysmethynil. We evaluated a panel of human pancreatic cancer cell lines and identified those that are sensitive to ICMT inhibition by cell viability assay. This responsiveness to ICMT inhibition was confirmed in in vivo xenograft tumor mouse models using both Cysmethynil and shRNA-targeting ICMT. Flow cytometry analysis after DAPI or PI staining is used to detect cell cycle arrest and apoptosis. We used western blot analysis to study autophagy, apoptosis and cell cycle markers. ShRNA for P21 is used for p21 knock down studies. SiRNA for p53 is used to study whether p21 induction is p53 dependent. BNIP3, ULK1 and ATG5 knock down was done using specific shRNAs to study their role in ICMT inhibition induced autophagy and apoptosis. BCL-xL is over expressed in the cells using retroviral vectors to study the role of apoptosis in ICMT inhibition induced cell death. Cell and mitochondrial respiration was determined by oxygen consumption rate analysis using Seahorse XF24 analyzer. Summary: In sensitive pancreatic cancer cells, ICMT inhibition induces mitochondrial respiratory deficiency and cellular energy depletion, leading to significant upregulation of p21 and p21 dependent induction of BNIP3 leading to autophagy and apoptosis. But unlike in prostate and liver cancer, ICMT inhibition induced apoptosis not the autophagy responsible for inhibition of cell viability in pancreatic cancer. Conclusion: These findings suggest ICMT is a potential therapeutic target against pancreatic cancers and atleast in pancreatic cancer, ICMT inhibition induced apoptosis but not autophagy responsible for its therapeutic efficacy. Citation Format: Kanjoormana A. Manu, Tin F. Chai, Jing T. Teh, Wan Zhu, Patrick J. Casey, Mei Wang. Targeting ICMT in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2339.
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inhibition of isoprenylcysteine carboxylmethyltransferase induces cell cycle arrest and apoptosis through p21 and p21 regulated bnip3 induction in pancreatic cancer
Molecular Cancer Therapeutics, 2017Co-Authors: Kanjoormana Aryan Manu, Jing Tsong Teh, Wan Long Zhu, Patrick J Casey, Tin Fan Chai, Mei WangAbstract:Pancreatic cancer remains one of the most difficult to treat human cancers despite recent advances in targeted therapy. Inhibition of isoprenylcysteine carboxylmethyltransferase (ICMT), an enzyme that posttranslationally modifies a group of proteins including several small GTPases, suppresses proliferation of some human cancer cells. However, the efficacy of ICMT inhibition on human pancreatic cancer has not been evaluated. In this study, we have evaluated a panel of human pancreatic cancer cell lines and identified those that are sensitive to ICMT inhibition. In these cells, ICMT suppression inhibited proliferation and induced apoptosis. This responsiveness to ICMT inhibition was confirmed in in vivo xenograft tumor mouse models using both a small-molecule inhibitor and shRNA-targeting ICMT. Mechanistically, we found that, in sensitive pancreatic cancer cells, ICMT inhibition induced mitochondrial respiratory deficiency and cellular energy depletion, leading to significant upregulation of p21. Furthermore, we characterized the role of p21 as a regulator and coordinator of cell signaling that responds to cell energy depletion. Apoptosis, but not autophagy, that is induced via p21-activated BNIP3 expression accounts for the efficacy of ICMT inhibition in sensitive pancreatic cancer cells in both in vitro and in vivo models. In contrast, cells resistant to ICMT inhibition demonstrated no mitochondria dysfunction or p21 signaling changes under ICMT suppression. These findings not only identify pancreatic cancers as potential therapeutic targets for ICMT suppression but also provide an avenue for identifying those subtypes that would be most responsive to agents targeting this critical enzyme. Mol Cancer Ther; 16(5); 914-23. ©2017 AACR.
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isoprenylcysteine carboxylmethyltransferase regulates mitochondrial respiration and cancer cell metabolism
Oncogene, 2015Co-Authors: Jing Tsong Teh, Wan Long Zhu, Olga Ilkayeva, Jessica R Gooding, Patrick J Casey, Scott A Summers, Christopher B Newgard, Mei WangAbstract:Isoprenylcysteine carboxylmethyltransferase (ICMT) catalyzes the last of the three-step posttranslational protein prenylation process for the so-called CaaX proteins, which includes many signaling proteins, such as most small GTPases. Despite extensive studies on ICMT and its regulation of cell functions, the mechanisms of much of the impact of ICMT on cellular functions remain unclear. Our recent studies demonstrated that suppression of ICMT results in induction of autophagy, inhibition of cell growth and inhibition of proliferation in various cancer cell types, prompting this investigation of potential metabolic regulation by ICMT. We report here the findings that ICMT inhibition reduces the function of mitochondrial oxidative phosphorylation in multiple cancer cell lines. In-depth oximetry analysis demonstrated that functions of mitochondrial complex I, II and III are subject to ICMT regulation. Consistently, ICMT inhibition decreased cellular ATP and depleted critical tricarboxylic acid cycle metabolites, leading to suppression of cell anabolism and growth, and marked autophagy. Several different approaches demonstrated that the impact of ICMT inhibition on cell proliferation and viability was largely mediated by its effect on mitochondrial respiration. This previously unappreciated function of ICMT, which can be therapeutically exploited, likely has a significant role in the impact of ICMT on tumorigenic processes.
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functionalized indoleamines as potent drug like inhibitors of isoprenylcysteine carboxyl methyltransferase ICMT
European Journal of Medicinal Chemistry, 2013Co-Authors: Pondy Murugappan Ramanujulu, Patrick J Casey, Tianming Yang, Siew Qi Yap, Fuichung Wong, Mei WangAbstract:The enzyme isoprenylcysteine carboxyl methyltransferase (ICMT) plays an important role in the post-translational modification of proteins involved in the regulation of cell growth and oncogenesis. The biological consequences of ICMT inhibition strongly implicate the enzyme as a potential therapeutic target for cancer and provide a compelling rationale for developing specific ICMT inhibitors as anti-cancer agents. We report here the systematic modification of the known ICMT inhibitor cysmethynil to give an analog 15 with greatly improved solubility and PAMPA permeability which was achieved with concurrent gains in ICMT inhibitory and cell-based antiproliferative activities. The modifications involved replacing the amide side chain of cysmethynil with a tertiary amine, and introducing an aminopyrimidine ring in place of m-tolyl. The presence of the weakly basic and polar aminopyrimidine ring contributed significantly to the potency and drug-like profile of the final compound.
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a small molecule inhibitor of isoprenylcysteine carboxymethyltransferase induces autophagic cell death in pc3 prostate cancer cells
Journal of Biological Chemistry, 2008Co-Authors: Mei Wang, Wanloo Tan, Jin Zhou, Jolene Leow, H S Lee, Patrick J CaseyAbstract:A number of proteins involved in cell growth control, including members of the Ras family of GTPases, are modified at their C terminus by a three-step posttranslational process termed prenylation. The enzyme isoprenylcysteine carboxylmethyl-transferase (ICMT) catalyzes the last step in this process, and genetic and pharmacological suppression of ICMT activity significantly impacts on cell growth and oncogenesis. Screening of a diverse chemical library led to the identification of a specific small molecule inhibitor of ICMT, cysmethynil, that inhibited growth factor signaling and tumorigenesis in an in vitro cancer cell model (Winter-Vann, A. M., Baron, R. A., Wong, W., dela Cruz, J., York, J. D., Gooden, D. M., Bergo, M. O., Young, S. G., Toone, E. J., and Casey, P. J. (2005) Proc. Natl. Acad. Sci. U. S. A. 102, 4336-4341). To further evaluate the mechanisms through which this ICMT inhibitor impacts on cancer cells, we developed both in vitro and in vivo models utilizing PC3 prostate cancer cells. Treatment of these cells with cysmethynil resulted in both an accumulation of cells in the G(1) phase and cell death. Treatment of mice harboring PC3 cell-derived xenograft tumors with cysmethynil resulted in markedly reduced tumor size. Analysis of cell death pathways unexpectedly showed minimal impact of cysmethynil treatment on apoptosis; rather, drug treatment significantly enhanced autophagy and autophagic cell death. Cysmethynil-treated cells displayed reduced mammalian target of rapamycin (mTOR) signaling, providing a potential mechanism for the excessive autophagy as well as G(1) cell cycle arrest observed. These results identify a novel mechanism for the antitumor activity of ICMT inhibition. Further, the dual effects of cell death and cell cycle arrest by cysmethynil treatment strengthen the rationale for targeting ICMT in cancer chemotherapy.
Quangde Nguyen - One of the best experts on this subject based on the ideXlab platform.
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imaging apoptosis with positron emission tomography bench to bedside development of the caspase 3 7 specific radiotracer 18 f ICMT 11
European Journal of Cancer, 2012Co-Authors: Quangde Nguyen, Graham Smith, Robin Fortt, Amarnath Challapalli, Eric O. AboagyeAbstract:The capacity to evade apoptosis has been defined as one of the hallmarks of cancer and, thus, effective anti-cancer therapy often induces apoptosis. A biomarker for imaging apoptosis could assist in monitoring the efficacy of a wide range of current and future therapeutics. Despite the potential, there are limited clinical examples of the use of positron emission tomography for imaging of apoptosis. [(18)F]ICMT-11 is a novel reagent designed to non-invasively image caspase-3 activation and, hence, drug-induced apoptosis. Radiochemistry development of [(18)F]ICMT-11 has been undertaken to improve specific radioactivity, reduce content of stable impurities, reduce synthesis time and enable automation for manufacture of multi-patient dose. Due to the promising mechanistic and safety profile of [(18)F]ICMT-11, the radiotracer is transitioning to clinical development and has been selected as a candidate radiotracer by the QuIC-ConCePT consortium for further evaluation in preclinical models and humans. A successful outcome will allow use of the radiotracer as qualified method for evaluating the pharmaceutical industry's next generation therapeutics.
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abstract a222 assessment of tumor response to therapy with the caspase 3 7 specific 18f ICMT 11 pet imaging tracer
Molecular Cancer Therapeutics, 2009Co-Authors: Quangde Nguyen, Matthias Glaser, Meg Perumal, Graham Smith, Edward G Robins, Eric O. AboagyeAbstract:Of the molecular biochemical alterations that occur during apoptosis, activation of caspases, notably caspase‐3, is probably the most attractive for developing specific in vivo molecular imaging probes. We recently designed a library of isatin‐5 sulfonamides and selected [18F]ICMT‐11 for further evaluation on the basis of sub‐nanomolar affinity for activated capsase‐3, high metabolic stability, and facile radiolabeling. We have demonstrated that [18F]ICMT‐11 binds to a range of drug‐induced apoptotic cancer cells in vitro and to 38C13 murine lymphoma xenografts in vivo by up to 2‐fold at 24 h post‐treatment compared to vehicle treatment. We further associated the increased signal intensity in tumors after drug treatment ‐ detected by whole body in vivo microPET imaging ‐ with increased apoptosis detected by immunohistochemistry, and have therefore characterized [18F]ICMT‐11 as a caspase‐3/7 specific PET imaging radiotracer for the assessment of tumor apoptosis that could find utility in anticancer drug development and the monitoring of early responses to therapy. In the present study, we have investigated the sensitivity of [18F]ICMT‐11 compared to [18F]DG in a longitudinal experimental protocol where the same tumor bearing mouse is subjected to pre‐ ,24h and 48h post‐cyclophosphamide treatment microPET imaging. The tumor volumes have been recorded throughout the study for comparison with PET generated data. [18F]ICMT‐11 PET images and imaging variables were characterized by a weak baseline tumor uptake in pretreated animals, which increased after 24h cyclophosphamide treatment, then decreased at 48h posttreatment to levels greater than that of baseline (NUV60 = 0.05±0.01, 0.12±0.03 and 0.09±0.03 at pre‐, 24h and 48h post‐treatment, respectively). In contrast, [18F]DG PET images and imaging variables showed a high tumor uptake in pretreated animals, as expected, that decreased progressively at 24 and 48h posttreatment (NUV60=3.33±0.24, 1.95±0.16 and 1.26±0.10 at pre‐, 24h and 48h post‐treatment, respectively). The changes in [18F]ICMT‐11 and [18F]DG uptake occurred in parallel with small reduction (94.3%±6.0 that of the pretreated mice tumor volumes) of the tumor volume at 24h posttreatment compared to pretreatment, and a more drastic shrinkage (29.9%±3.6 that of the pretreated mice tumor volumes) at 48h posttreatment. We showed that both [18F]ICMT‐11 and [18F]DG PET can be use to monitor response to cyclophosphamide treatment in our longitudinal experimental model. At 24h and 48h posttreatment, [18F]ICMT‐11 PET imaging detects increased tumor apoptosis and [18F]DG PET detects decreased tumor metabolic activity. At 24h posttreatment, the increased [18F]ICMT‐11 and decreased [18F]DG PET tumor intensity signals are associated with only a small decrease in tumor volumes. In contrast, we observed a drastic tumor shrinkage at 48h posttreatment that was, however, associated with less tumor apoptosis detected by [18F]ICMT‐11 and almost no tumor metabolic activity. It is possible that the early increase in tumor apoptosis (24 h) led to tumor shrinkage. Our future studies will investigate [18F]ICMT‐11 PET imaging assessment of tumor response to therapy using a specific apoptosis targeting drug in the same longitudinal experimental model. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A222.
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positron emission tomography imaging of drug induced tumor apoptosis with a caspase 3 7 specific 18f labeled isatin sulfonamide
Proceedings of the National Academy of Sciences of the United States of America, 2009Co-Authors: Quangde Nguyen, Matthias Glaser, Meg Perumal, Erik Arstad, Graham Smith, Eric O. AboagyeAbstract:Of the molecular biochemical alterations that occur during apoptosis, activation of caspases, notably caspase-3, is probably the most attractive for developing specific in vivo molecular imaging probes. We recently designed a library of isatin-5 sulfonamides and selected [18F]ICMT-11 for further evaluation on the basis of subnanomolar affinity for activated capsase-3, high metabolic stability, and facile radiolabeling. In this present study, we have demonstrated that [18F]ICMT-11 binds to a range of drug-induced apoptotic cancer cells in vitro and to 38C13 murine lymphoma xenografts in vivo by up to 2-fold at 24 h posttreatment compared to vehicle treatment. We further demonstrated that the increased signal intensity in tumors after drug treatment, detected by whole body in vivo microPET imaging, was associated with increased apoptosis. In summary, we have characterized [18F]ICMT-11 as a caspase-3/7 specific PET imaging radiotracer for the assessment of tumor apoptosis that could find utility in anticancer drug development and the monitoring of early responses to therapy.
