See more on www.hypoxiaalberta.org Phone: +1.780.989.4313 Address: Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta, Canada T6G 1Z2
Solid tumors are often poorly vascularized, which impairs oxygen supply and drug delivery to the ... more Solid tumors are often poorly vascularized, which impairs oxygen supply and drug delivery to the cells. This often leads to genetic and translational adaptations that promote tumor progression, invasion, metastasis, and resistance to conventional chemo-/radiotherapy and immunotherapy. A hypoxia-directed nanosensitizer formulation of a hypoxia-activated prodrug (HAP) was developed by encapsulating iodoazomycin arabinofuranoside (IAZA), a 2-nitroimidazole nucleoside-based HAP, in a functionally modified carbohydrate-based nanogel, facilitating delivery and accrual selectively in the hypoxic head and neck and prostate cancer cells. Although IAZA has been reported as a clinically validated hypoxia diagnostic agent, recent studies have pointed to its promising hypoxia-selective anti-tumor properties, which make IAZA an excellent candidate for further exploration as a multimodal theranostic of hypoxic tumors. The nanogels are composed of a galactose-based shell with an inner core of thermoresponsive (di(ethylene glycol) methyl ethyl methacrylate). Optimization of the nanogels led to high IAZA-loading capacity (≅80−88%) and a slow time-controlled release over 50 h. Furthermore, nanoIAZA (encapsulated IAZA) displayed superior in vitro hypoxia-selective cytotoxicity and radiosensitization in comparison to free IAZA in the head and neck (FaDu) and prostate (PC3) cancer cell lines. The acute systemic toxicity profile of the nanogel (NG1) was studied in immunocompromised mice, indicating no signs of toxicity. Additionally, growth inhibition of subcutaneous FaDu xenograft tumors was observed with nanoIAZA, demonstrating that this nanoformulation offers a significant improvement in tumor regression and overall survival compared to the control.
Tumour hypoxia negatively impacts therapy outcomes and continues to be a major unsolved clinical ... more Tumour hypoxia negatively impacts therapy outcomes and continues to be a major unsolved clinical problem. Nitroimidazoles are hypoxia selective compounds that become entrapped in hypoxic cells by forming drugprotein adducts. They are widely used as hypoxia diagnostics and have also shown promise as hypoxiadirected therapeutics. However, little is known about the protein targets of nitroimidazoles and the resulting effects of their modification on cancer cells. Here, we report the synthesis and applications of azidoazomycin arabinofuranoside (N 3-AZA), a novel click-chemistry compatible 2-nitroimidazole, designed to facilitate (a) the LC-MS/MS-based proteomic analysis of 2-nitroimidazole targeted proteins in FaDu head and neck cancer cells, and (b) rapid and efficient labelling of hypoxic cells and tissues. Bioinformatic analysis revealed that many of the 62 target proteins we identified participate in key canonical pathways including glycolysis and HIF1A signaling that play critical roles in the cellular response to hypoxia. Critical cellular proteins such as the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and the detoxification enzyme glutathione S-transferase P (GSTP1) appeared as top hits, and N 3-AZA adduct formation significantly reduced their enzymatic activities only under hypoxia. Therefore, GAPDH, GSTP1 and other proteins reported here may represent candidate targets to further enhance the potential for nitroimidazole-based cancer therapeutics.
Journal of Pharmacy Pharmaceutical Sciences a Publication of the Canadian Society For Pharmaceutical Sciences Societe Canadienne Des Sciences Pharmaceutiques, 2007
Purpose: 18F-Fluoroestradiol [18F]FES has emerged as a valuable PET tracer to predict the respons... more Purpose: 18F-Fluoroestradiol [18F]FES has emerged as a valuable PET tracer to predict the response to hormone therapy in recurrent or metastatic breast cancer patients. A clinically acceptable product requires a rapid reliable synthesis and must be demonstrated to maintain chemical stability and receptor specific uptake during patient studies. [18F]FES then becomes a dependable tracer for the evaluation and management of breast cancer patients. Methods: An improved automated radiosynthesis of [18F]FES was developed. Stability studies of the injectible form of [18F]FES were performed up to 24 h after dose formulation under normal storage conditions. A comparative FES/FDG PET imaging in ER+ breast cancer patients is reported. Results: The improved synthesis procedure utilizes fewer hydrolysis steps and a single high performance liquid column chromatography (HPLC) purification of the labeled mixture affording [18F]FES in good yield with high radiochemical purity (>99%). Stability studies with purified [18F]FES in saline/ethanol (85:15 v/v) indicated no radiolytic or chemical degradation of this radiopharmaceutical when stored for 24 h at 20-24 degrees C. Positron Emission Tomography (PET) studies with [18F]FES and [18F]FDG in estrogen receptor positive (ER+) breast cancer patients indicated that while FDG accumulation was seen in all metabolically hyperactive sites, the uptake of FES clearly delineated the ER+ tissues regions. Conclusions: An improved automated synthesis of [18F]FES has been developed and the integrity of this product has been validated by long term stability studies and clinical PET imaging studies in ER+ breast cancer patients. A lack of concordance between FES and FDG uptake in a patient with metastatic breast cancer suggests specificity of the FES for tumors expressing estrogen receptors.
A group of N-substituted-1,4-dihydropyridylacetic acids (13-16), esters (4-12), and amides (17-23... more A group of N-substituted-1,4-dihydropyridylacetic acids (13-16), esters (4-12), and amides (17-23) were synthesized in order to investigate the effect of 4-substituents (R2 = Ph, n-Bu or Me) and alpha-substituents (R3 = H, Me) on antiinflammatory activity. In the acetic ester class of compounds, the relative activities (R2-substituents) were Ph greater than n-Bu greater than Me. The presence of an R3 methyl substituent enhanced activity. Increasing the length of the alkyl ester substituent enhanced activity, since the tri-ester (7) was more active than the bis-ester (6), and the bis-ester (11) was more active than the mono-ester (10). The relative order of antiinflammatory potency was generally ester greater than amide greater than acid. Methyl 2-methyl-2-(-1-[4-phenyl-3-(4,4-dimethyloxazolin-2-yl)-1,4-dihy dropyridyl]) acetate (9) was the most active antiinflammatory agent in the series, reducing inflammation 73.9% at 3 hr after a 100 mg/kg po dose.
The current work evaluates 1-alpha-d-(2-deoxy-2-fluororibofuranosyl)-2-nitroimidazole (FRAZ), a n... more The current work evaluates 1-alpha-d-(2-deoxy-2-fluororibofuranosyl)-2-nitroimidazole (FRAZ), a novel azomycin nucleoside that is a potential radiosensitizer of tumor hypoxia. FRAZ is a ribose analogue of 1-alpha-d-(2-deoxy-2-fluoroarabinofuranosyl)-2-nitroimidazole ([(18)F]-FAZA), a clinically used hypoxia marker. Preliminary assessment of the cytotoxicity and hypoxia-specific in vitro binding in HCT-110 colorectal cancer cells indicate that the radiosensitization properties of FRAZ are similar to that of FAZA, with a sensitizer enhancement ratio (SER) of approximately 1.8. An automated radiosynthesis of [(18)F]-FRAZ using a commercial automated synthesis unit (ASU) was established (synthesis time approximately 32 min; radiochemical yield (decay uncorrecetd) approximately 22%) to facilitate its application in PET-based diagnosis of hypoxic tumors.
Index Medicus for South-East Asia Region (IMSEAR) is a compiled and maintained by Information Man... more Index Medicus for South-East Asia Region (IMSEAR) is a compiled and maintained by Information Management and Dissemination Unit, Department of Sustainable Development and Healthy Environments, World Health Organization, Regional Office for South-East Asia.
A group of N-substituted-1,4-dihydropyridylacetic acids (13-16), esters (4-12), and amides (17-23... more A group of N-substituted-1,4-dihydropyridylacetic acids (13-16), esters (4-12), and amides (17-23) were synthesized in order to investigate the effect of 4-substituents (R2 = Ph, n-Bu or Me) and alpha-substituents (R3 = H, Me) on antiinflammatory activity. In the acetic ester class of compounds, the relative activities (R2-substituents) were Ph greater than n-Bu greater than Me. The presence of an R3 methyl substituent enhanced activity. Increasing the length of the alkyl ester substituent enhanced activity, since the tri-ester (7) was more active than the bis-ester (6), and the bis-ester (11) was more active than the mono-ester (10). The relative order of antiinflammatory potency was generally ester greater than amide greater than acid. Methyl 2-methyl-2-(-1-[4-phenyl-3-(4,4-dimethyloxazolin-2-yl)-1,4-dihy dropyridyl]) acetate (9) was the most active antiinflammatory agent in the series, reducing inflammation 73.9% at 3 hr after a 100 mg/kg po dose.
Solid tumors are often poorly vascularized, which impairs oxygen supply and drug delivery to the ... more Solid tumors are often poorly vascularized, which impairs oxygen supply and drug delivery to the cells. This often leads to genetic and translational adaptations that promote tumor progression, invasion, metastasis, and resistance to conventional chemo-/radiotherapy and immunotherapy. A hypoxia-directed nanosensitizer formulation of a hypoxia-activated prodrug (HAP) was developed by encapsulating iodoazomycin arabinofuranoside (IAZA), a 2-nitroimidazole nucleoside-based HAP, in a functionally modified carbohydrate-based nanogel, facilitating delivery and accrual selectively in the hypoxic head and neck and prostate cancer cells. Although IAZA has been reported as a clinically validated hypoxia diagnostic agent, recent studies have pointed to its promising hypoxia-selective anti-tumor properties, which make IAZA an excellent candidate for further exploration as a multimodal theranostic of hypoxic tumors. The nanogels are composed of a galactose-based shell with an inner core of thermoresponsive (di(ethylene glycol) methyl ethyl methacrylate). Optimization of the nanogels led to high IAZA-loading capacity (≅80−88%) and a slow time-controlled release over 50 h. Furthermore, nanoIAZA (encapsulated IAZA) displayed superior in vitro hypoxia-selective cytotoxicity and radiosensitization in comparison to free IAZA in the head and neck (FaDu) and prostate (PC3) cancer cell lines. The acute systemic toxicity profile of the nanogel (NG1) was studied in immunocompromised mice, indicating no signs of toxicity. Additionally, growth inhibition of subcutaneous FaDu xenograft tumors was observed with nanoIAZA, demonstrating that this nanoformulation offers a significant improvement in tumor regression and overall survival compared to the control.
Tumour hypoxia negatively impacts therapy outcomes and continues to be a major unsolved clinical ... more Tumour hypoxia negatively impacts therapy outcomes and continues to be a major unsolved clinical problem. Nitroimidazoles are hypoxia selective compounds that become entrapped in hypoxic cells by forming drugprotein adducts. They are widely used as hypoxia diagnostics and have also shown promise as hypoxiadirected therapeutics. However, little is known about the protein targets of nitroimidazoles and the resulting effects of their modification on cancer cells. Here, we report the synthesis and applications of azidoazomycin arabinofuranoside (N 3-AZA), a novel click-chemistry compatible 2-nitroimidazole, designed to facilitate (a) the LC-MS/MS-based proteomic analysis of 2-nitroimidazole targeted proteins in FaDu head and neck cancer cells, and (b) rapid and efficient labelling of hypoxic cells and tissues. Bioinformatic analysis revealed that many of the 62 target proteins we identified participate in key canonical pathways including glycolysis and HIF1A signaling that play critical roles in the cellular response to hypoxia. Critical cellular proteins such as the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and the detoxification enzyme glutathione S-transferase P (GSTP1) appeared as top hits, and N 3-AZA adduct formation significantly reduced their enzymatic activities only under hypoxia. Therefore, GAPDH, GSTP1 and other proteins reported here may represent candidate targets to further enhance the potential for nitroimidazole-based cancer therapeutics.
Journal of Pharmacy Pharmaceutical Sciences a Publication of the Canadian Society For Pharmaceutical Sciences Societe Canadienne Des Sciences Pharmaceutiques, 2007
Purpose: 18F-Fluoroestradiol [18F]FES has emerged as a valuable PET tracer to predict the respons... more Purpose: 18F-Fluoroestradiol [18F]FES has emerged as a valuable PET tracer to predict the response to hormone therapy in recurrent or metastatic breast cancer patients. A clinically acceptable product requires a rapid reliable synthesis and must be demonstrated to maintain chemical stability and receptor specific uptake during patient studies. [18F]FES then becomes a dependable tracer for the evaluation and management of breast cancer patients. Methods: An improved automated radiosynthesis of [18F]FES was developed. Stability studies of the injectible form of [18F]FES were performed up to 24 h after dose formulation under normal storage conditions. A comparative FES/FDG PET imaging in ER+ breast cancer patients is reported. Results: The improved synthesis procedure utilizes fewer hydrolysis steps and a single high performance liquid column chromatography (HPLC) purification of the labeled mixture affording [18F]FES in good yield with high radiochemical purity (>99%). Stability studies with purified [18F]FES in saline/ethanol (85:15 v/v) indicated no radiolytic or chemical degradation of this radiopharmaceutical when stored for 24 h at 20-24 degrees C. Positron Emission Tomography (PET) studies with [18F]FES and [18F]FDG in estrogen receptor positive (ER+) breast cancer patients indicated that while FDG accumulation was seen in all metabolically hyperactive sites, the uptake of FES clearly delineated the ER+ tissues regions. Conclusions: An improved automated synthesis of [18F]FES has been developed and the integrity of this product has been validated by long term stability studies and clinical PET imaging studies in ER+ breast cancer patients. A lack of concordance between FES and FDG uptake in a patient with metastatic breast cancer suggests specificity of the FES for tumors expressing estrogen receptors.
A group of N-substituted-1,4-dihydropyridylacetic acids (13-16), esters (4-12), and amides (17-23... more A group of N-substituted-1,4-dihydropyridylacetic acids (13-16), esters (4-12), and amides (17-23) were synthesized in order to investigate the effect of 4-substituents (R2 = Ph, n-Bu or Me) and alpha-substituents (R3 = H, Me) on antiinflammatory activity. In the acetic ester class of compounds, the relative activities (R2-substituents) were Ph greater than n-Bu greater than Me. The presence of an R3 methyl substituent enhanced activity. Increasing the length of the alkyl ester substituent enhanced activity, since the tri-ester (7) was more active than the bis-ester (6), and the bis-ester (11) was more active than the mono-ester (10). The relative order of antiinflammatory potency was generally ester greater than amide greater than acid. Methyl 2-methyl-2-(-1-[4-phenyl-3-(4,4-dimethyloxazolin-2-yl)-1,4-dihy dropyridyl]) acetate (9) was the most active antiinflammatory agent in the series, reducing inflammation 73.9% at 3 hr after a 100 mg/kg po dose.
The current work evaluates 1-alpha-d-(2-deoxy-2-fluororibofuranosyl)-2-nitroimidazole (FRAZ), a n... more The current work evaluates 1-alpha-d-(2-deoxy-2-fluororibofuranosyl)-2-nitroimidazole (FRAZ), a novel azomycin nucleoside that is a potential radiosensitizer of tumor hypoxia. FRAZ is a ribose analogue of 1-alpha-d-(2-deoxy-2-fluoroarabinofuranosyl)-2-nitroimidazole ([(18)F]-FAZA), a clinically used hypoxia marker. Preliminary assessment of the cytotoxicity and hypoxia-specific in vitro binding in HCT-110 colorectal cancer cells indicate that the radiosensitization properties of FRAZ are similar to that of FAZA, with a sensitizer enhancement ratio (SER) of approximately 1.8. An automated radiosynthesis of [(18)F]-FRAZ using a commercial automated synthesis unit (ASU) was established (synthesis time approximately 32 min; radiochemical yield (decay uncorrecetd) approximately 22%) to facilitate its application in PET-based diagnosis of hypoxic tumors.
Index Medicus for South-East Asia Region (IMSEAR) is a compiled and maintained by Information Man... more Index Medicus for South-East Asia Region (IMSEAR) is a compiled and maintained by Information Management and Dissemination Unit, Department of Sustainable Development and Healthy Environments, World Health Organization, Regional Office for South-East Asia.
A group of N-substituted-1,4-dihydropyridylacetic acids (13-16), esters (4-12), and amides (17-23... more A group of N-substituted-1,4-dihydropyridylacetic acids (13-16), esters (4-12), and amides (17-23) were synthesized in order to investigate the effect of 4-substituents (R2 = Ph, n-Bu or Me) and alpha-substituents (R3 = H, Me) on antiinflammatory activity. In the acetic ester class of compounds, the relative activities (R2-substituents) were Ph greater than n-Bu greater than Me. The presence of an R3 methyl substituent enhanced activity. Increasing the length of the alkyl ester substituent enhanced activity, since the tri-ester (7) was more active than the bis-ester (6), and the bis-ester (11) was more active than the mono-ester (10). The relative order of antiinflammatory potency was generally ester greater than amide greater than acid. Methyl 2-methyl-2-(-1-[4-phenyl-3-(4,4-dimethyloxazolin-2-yl)-1,4-dihy dropyridyl]) acetate (9) was the most active antiinflammatory agent in the series, reducing inflammation 73.9% at 3 hr after a 100 mg/kg po dose.
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Papers by Piyush Kumar