Bonnie Kuehl - Academia.edu (original) (raw)

Papers by Bonnie Kuehl

The British journal of cancer. Supplement, 1996

Transfection of a normal human diploid fibroblast cell strain, GM38, with a simian virus 40 (SV40... more Transfection of a normal human diploid fibroblast cell strain, GM38, with a simian virus 40 (SV40) large T antigen containing plasmid, yielded an immortal cell line, G38-8X, which had a similar sensitivity as the parental cell strain to the quinone-containing chemotherapeutic agent mitomycin C (MMC), under both aerobic and hypoxic exposure conditions. The activity level of DT-diaphorase was similar in both the parental GM38 and G38-8X cells. Although DT-diaphorase could be detected by Western blot analysis, using two mouse anti-human monoclonal antibodies, in GM38 cells, it was not detected in the G38-8X cells. G38-8X cells have a slightly increased P450R activity (2-fold), and have elevated P-glycoprotein levels compared with the parental GM38 cell strain. The immortal G38-8X cell line is 2-fold more resistant to ionising radiation than the parental GM38 cell strain (D10 approximately 5 Gy). Although these SV40 large T antigen immortalised human diploid fibroblasts behaved similarl...

Oncology research, 1993

Three related Chinese hamster ovary (CHO) cell lines derived from CHO-K1R cells (MMC3-A2, 21-1 an... more Three related Chinese hamster ovary (CHO) cell lines derived from CHO-K1R cells (MMC3-A2, 21-1 and G1B) previously shown to differ in their sensitivity to mitomycin C (MMC), were investigated in more detail to determine the factors controlling this sensitivity. A separately maintained wild type cell line (CHO-K1TOR) was included in this study for comparison. Continuous (chronic) exposure of the five cell lines to MMC during the 10-day colony forming assay demonstrated a 15-fold range in MMC sensitivity between the most sensitive cell line (MMC3-A2) and the most resistant cell line (G1B) with CHO-K1R, 21-1 and CHO-K1TOR falling at intermediate levels. Acute aerobic exposure (0-5 h) to MMC resulted in a reduced fivefold range of sensitivities, which was further reduced to a three-fold range under hypoxic exposure conditions. These results were suggestive of differences in the aerobic enzymatic activation of MMC as a possible mechanism contributing to the varying sensitivities. There w...

Healthcare Management Forum, 2014

Hospital formularies, guided by the Pharmacy and Therapeutics Committee, exist to optimize medica... more Hospital formularies, guided by the Pharmacy and Therapeutics Committee, exist to optimize medication use by identifying and designating drugs of choice to guide rational prescribing, ultimately reducing patient risk and costs and improving patient outcomes. Guidelines and a framework exist to guide critical evaluations of medications for formulary listing; however, there may be opportunities to improve and standardize how a formulary change could be instituted in Canadian hospitals. A formulary change at an Ontario hospital revealed that there are some key challenges to the formulary change process including the importance of a robust project plan, appropriate resources, healthcare staff education, and acceptance.

Healthcare Management Forum, 2014

Les formulaires des hôpitaux, orientés par les comités pharmaceutiques et thérapeutiques, sont cr... more Les formulaires des hôpitaux, orientés par les comités pharmaceutiques et thérapeutiques, sont créés pour optimiser l'utilisation des médicaments, car ils déterminent et désignent les médicaments de choix pour favoriser des prescriptions rationnelles, limiter les risques pour le patient, réduire les coûts et améliorer les résultats cliniques. Des lignes directrices et un cadre guident les évaluations critiques des médicaments inscrits dans la liste de formulaires. Cependant, il est peut-être possible d'améliorer et de standardiser le mode d'adoption d'un changement aux formulaires dans les hôpitaux canadiens. Le changement au formulaire d'un hôpital ontarien a révélé de graves problèmes associés à ce processus, y compris l'importance d'un plan d'exécution solide, de ressources adaptées, de la formation du personnel soignant et de l'acceptation.

Skin therapy letter, 2003

Skin cleansers may be an important adjunct to the regimen of those who use cosmetics, have sensit... more Skin cleansers may be an important adjunct to the regimen of those who use cosmetics, have sensitive or compromised skin, or utilize topical therapies. Cleansers emulsify dirt, oil and microorganisms on the skin surface so that they can be easily removed. During cleansing, there is a complex interaction between the cleanser, the moisture skin barrier, and skin pH. Cleansing, with water soap or a liquid cleanser, will affect the moisture skin barrier. Soap will bring about the greatest changes to the barrier and increase skin pH. Liquid facial cleansers are gentler, effecting less disruption of the barrier, with minimal change to skin pH, and can provide people with a cleanser that is a combination of surfactant classes, moisturizers and acidic pH in order to minimize disruption to the skin barrier.

Carcinogenesis, 1998

The Bloom's syndrome gene, BLM, encodes a protein which bears homology to the RecQ helicases. It ... more The Bloom's syndrome gene, BLM, encodes a protein which bears homology to the RecQ helicases. It is believed to be involved in DNA replication and has been implicated in the maintenance of genomic stability. To investigate whether BLM was involved in cellular responses to DNA damage Bloom's syndrome fibroblasts were treated with either UV or ionizing radiation and the levels of p53 and two of its down stream effectors, p21 waf1/cip1 and hdm2, were determined by western blot analysis. Following 20 J/m 2 UVC-radiation we observed that the maximal accumulation of p21 waf1/cip1 and hdm2 proteins preceded that of p53 in both a normal diploid fibroblast cell strain (GM0038) and in two Bloom's syndrome cell strains. Furthermore, the Bloom's syndrome cells demonstrated a delayed and prolonged accumulation of all three proteins and a delayed recovery of the protein levels back to pre-damage levels compared with the normal cell strain. Conversely, normal and Bloom's syndrome cell response following 2.5 Gy of ionizing radiation was quite similar for p21 waf1/cip1 and hdm2, but differed significantly for p53. Maximum accumulation of p53 occurred within 2 h of damage and preceded that of p21 waf1/cip1 and hdm2. These results suggest that the BLM protein may play a role in the detection of certain types of DNA damage and in the cellular response to that damage.

Canadian Journal of Diabetes, 2015

This program has received financial support from no one in the form of anything. • This program h... more This program has received financial support from no one in the form of anything. • This program has received in-kind support from no one in the form of anything.

Canadian journal of kidney health and disease, 2016

Hyponatremia is a recognized complication of congestive heart failure (CHF) and is associated wit... more Hyponatremia is a recognized complication of congestive heart failure (CHF) and is associated with reduced survival. Therefore, early identification and appropriate management of hyponatremia is important. The aim of this study was to determine the general approach amongst Canadian healthcare practitioners and trainees to the identification and management of hyponatremia complicating CHF. Respondents completed 15 multiple-choice style questions in 3 case scenarios regarding the approach to management of hyponatremia complicating CHF using an online survey on UKidney.com between November 2012 and May 2013. Results were presented as a proportion of averaged correct/incorrect responses amongst Canadian nephrologists, cardiologists, internists and trainees in each of two domains; pathophysiology and management. Management was further subdivided into correct and incorrect use of diuretic therapy, hypertonic saline, oral urea tablets, vasopressin receptor antagonists (vaptans) and rate of...

SAGE Open Medicine, 2015

Objective: Allergic rhinitis is a common, usually long-standing, condition that may be self-diagn... more Objective: Allergic rhinitis is a common, usually long-standing, condition that may be self-diagnosed or have a formal diagnosis. Our aim was to identify how allergic rhinitis sufferers self-manage their condition. Methods: A sample of 276 self-identified adult allergy sufferers pooled from social media completed an online survey comprising 13 questions. The survey was fielded by a professional research organization (Lab42). The main outcome measures included the use of prescription and/or non-prescription allergy medication, and interactions with physician and/ or pharmacist with respect to medication use. Results: Of the respondents, 53% (146/276) indicated that they used both prescription and over-the-counter medication to manage their allergy symptoms. Of those who used prescription medication, 53% reported that they discussed their prescription medication in great detail with their physician when it was prescribed, while 42% spoke about it briefly. Following the initial prescription, few discussions about the prescription occur with the physician (45% indicate several discussions, 40% indicate one or two discussions, and 10% indicate no discussions). In most cases (~75% of the time), allergy prescription refills did not require a doctor visit with patients obtaining refills through phone calls to the doctor's office or through the pharmacy. Two-thirds of patients (69%) report that they have discussed their prescription allergy medication with a pharmacist, with greater than half of respondents having discussed the use of the non-prescription medication with their doctor. Conclusion: Patients with diagnosed allergic rhinitis appear to be self-managing their condition with few interactions with their doctor about their allergy prescription. Interactions with a pharmacist about allergy medication (prescription and nonprescription) appear to be more common than interactions with a physician.

Current Oncology, Feb 20, 2015

Guideline questions and recommendations related to the treatment of venous thromboembolism (vte) ... more Guideline questions and recommendations related to the treatment of venous thromboembolism (vte) Category Question Recommendations Strength of evidence Grade Consensus category Preferred therapy and dosing

British Journal of Cancer, 1995

Summ_uxy A point mutation in the mRNA of NADP(H): quinone oxidoreductase 1 (NQOI, DT-diaphorase) ... more Summ_uxy A point mutation in the mRNA of NADP(H): quinone oxidoreductase 1 (NQOI, DT-diaphorase) is believed to be responsible for reduced enzyme activity in the adenocarcinoma BE cell line. The present study examined nine cultured human non-cancerous fibroblast cell strains, five of which were from members of a single cancer-prone family, which demonstrated widely varying activity levels of DT-diaphorase (41-3462 nmol min-'mg-' protein), to determine if genetic alteration of the NQOI or NOQ2 gene was involved in determining enzyme activity. All cell strains expressed NQOI and NQO. mRNA as measured by a quantitative polymerase chain reaction amplification technique. No relationship was found between the level of mRNA expressed and the enzyme activity in the cells. Sequencing of the entire complementary DNA from the cell strains revealed only a single base substitution at nucleotide 609 in one allele encoding NQOI in every cell strain from members of the cancer-prone family, except for one cell strain which expressed only the T at nucleotide 609 in both alleles. Subsequent examination of genomic DNA from 44 individuals revealed that this base substitution is present in approximately 50%0 of the population. The presence of the T at nucleotide 609 in the NQOI locus does not appear to be directly causal for altered DT-diaphorase activity.

Cancer and Metastasis Reviews, 1993

Mitomycin C is being used as an adjunct to ionizing radiation in the treatment of some solid tumo... more Mitomycin C is being used as an adjunct to ionizing radiation in the treatment of some solid tumors. A rationale for this is that radioresistant hypoxic cells in solid tumors will have enhanced sensitivity to this bioreductively activated drug, compared to aerobic cells. The role of oxygen concentration and enzymatic drug reduction in bioreductive drug activation have been investigated. Techniques are reviewed for thein vitro determination of the oxygen concentration dependency of bioreductive drug activation. One of these techniques, an open cell suspension system using Chinese hamster ovary cells, is described. Results are shown that indicate that the oxygen concentration dependency of toxicity of mitomycin C and one of its analogues porfiromycin, though qualitatively complementing the oxygen dependency of ionizing radiation toxicity, are not quantitatively optimal. Using a mitomycin C resistant human cell strain (3437T) from a cancer prone family, a possible role for DT-diaphorase, an oxygen insensitive 2-electron transfer enzyme, is suggested. A correlation between a low level of DT-diaphorase in 3437T cells and mitomycin C resistance under aerobic exposure conditions is seen. Under hypoxic exposure conditions this resistance is lost, suggesting 1-electron transfer enzymes control hypoxic cell bioreductive activation. An activation role for DT-diaphorase in mitomycin C toxicity in the treatment of solid tumors is contrasted to a potential detoxification role for the enzyme with other xenobiotics in the cancer prone family phenotype.

British Journal of Cancer, 1996

A polymorphism in NAD(P)H:quinone oxidoreductase (NQO1): relationship of a homozygous mutation at... more A polymorphism in NAD(P)H:quinone oxidoreductase (NQO1): relationship of a homozygous mutation at position 609 of the NQO1 cDNA to NQO1 activity Sir -NQO1 has attracted considerable attention owing to its ability to deactivate a broad range of xenobiotics while activating certain anti-tumour quinones . A number of recent reports have highlighted the occurrence and potential significance of a point mutation in the NQO1 gene which is associated with a loss of NQO1 activity in both normal and tumour tissue Eickelmann et al., 1994a,b;. The mutation is a C to T point mutation at position 609 of the NQO1 cDNA which codes for a proline to serine substitution in the amino acid sequence of the protein . The mutation was originally characterised in the BE human colon adenocarcinoma cell line by SSCP analysis and sequencing and subsequently in the H596 human non-small-cell lung cancer cell line by a polymerase chain reactionrestriction fragment length polymorphism (PCR-RFLP) technique . Both the BE and H596 cell lines had moderate NQO1 mRNA expression but extremely low or non-detectable NQO1 activity. Purified, recombinant BE and H596 mutant NQO1 proteins expressed in E. coli have residual activity (< 10% of wild-type). While both BE and H596 recombinant mutant proteins reacted with a mouse monoclonal antibody raised against human NQO1, immunoblot analysis of BE and H596 cell lines did not detect NQO1 protein expression . This suggests that in cells the mutant protein may not be made or that the mutant protein may be made but rapidly degraded. Kuehl et al. (1995) have recently examined the relationship between the heterozygous mutation at position 609 and NQO1 activity. These data demonstrate a wide range of NQO1 activity in IC to T heterozygotes and suggests a significant role for post-transcriptional modification in determination of NQO1 activity.

The British journal of cancer. Supplement, 1996

Transfection of a normal human diploid fibroblast cell strain, GM38, with a simian virus 40 (SV40... more Transfection of a normal human diploid fibroblast cell strain, GM38, with a simian virus 40 (SV40) large T antigen containing plasmid, yielded an immortal cell line, G38-8X, which had a similar sensitivity as the parental cell strain to the quinone-containing chemotherapeutic agent mitomycin C (MMC), under both aerobic and hypoxic exposure conditions. The activity level of DT-diaphorase was similar in both the parental GM38 and G38-8X cells. Although DT-diaphorase could be detected by Western blot analysis, using two mouse anti-human monoclonal antibodies, in GM38 cells, it was not detected in the G38-8X cells. G38-8X cells have a slightly increased P450R activity (2-fold), and have elevated P-glycoprotein levels compared with the parental GM38 cell strain. The immortal G38-8X cell line is 2-fold more resistant to ionising radiation than the parental GM38 cell strain (D10 approximately 5 Gy). Although these SV40 large T antigen immortalised human diploid fibroblasts behaved similarl...

Oncology research, 1993

Three related Chinese hamster ovary (CHO) cell lines derived from CHO-K1R cells (MMC3-A2, 21-1 an... more Three related Chinese hamster ovary (CHO) cell lines derived from CHO-K1R cells (MMC3-A2, 21-1 and G1B) previously shown to differ in their sensitivity to mitomycin C (MMC), were investigated in more detail to determine the factors controlling this sensitivity. A separately maintained wild type cell line (CHO-K1TOR) was included in this study for comparison. Continuous (chronic) exposure of the five cell lines to MMC during the 10-day colony forming assay demonstrated a 15-fold range in MMC sensitivity between the most sensitive cell line (MMC3-A2) and the most resistant cell line (G1B) with CHO-K1R, 21-1 and CHO-K1TOR falling at intermediate levels. Acute aerobic exposure (0-5 h) to MMC resulted in a reduced fivefold range of sensitivities, which was further reduced to a three-fold range under hypoxic exposure conditions. These results were suggestive of differences in the aerobic enzymatic activation of MMC as a possible mechanism contributing to the varying sensitivities. There w...

Healthcare Management Forum, 2014

Hospital formularies, guided by the Pharmacy and Therapeutics Committee, exist to optimize medica... more Hospital formularies, guided by the Pharmacy and Therapeutics Committee, exist to optimize medication use by identifying and designating drugs of choice to guide rational prescribing, ultimately reducing patient risk and costs and improving patient outcomes. Guidelines and a framework exist to guide critical evaluations of medications for formulary listing; however, there may be opportunities to improve and standardize how a formulary change could be instituted in Canadian hospitals. A formulary change at an Ontario hospital revealed that there are some key challenges to the formulary change process including the importance of a robust project plan, appropriate resources, healthcare staff education, and acceptance.

Healthcare Management Forum, 2014

Les formulaires des hôpitaux, orientés par les comités pharmaceutiques et thérapeutiques, sont cr... more Les formulaires des hôpitaux, orientés par les comités pharmaceutiques et thérapeutiques, sont créés pour optimiser l'utilisation des médicaments, car ils déterminent et désignent les médicaments de choix pour favoriser des prescriptions rationnelles, limiter les risques pour le patient, réduire les coûts et améliorer les résultats cliniques. Des lignes directrices et un cadre guident les évaluations critiques des médicaments inscrits dans la liste de formulaires. Cependant, il est peut-être possible d'améliorer et de standardiser le mode d'adoption d'un changement aux formulaires dans les hôpitaux canadiens. Le changement au formulaire d'un hôpital ontarien a révélé de graves problèmes associés à ce processus, y compris l'importance d'un plan d'exécution solide, de ressources adaptées, de la formation du personnel soignant et de l'acceptation.

Skin therapy letter, 2003

Skin cleansers may be an important adjunct to the regimen of those who use cosmetics, have sensit... more Skin cleansers may be an important adjunct to the regimen of those who use cosmetics, have sensitive or compromised skin, or utilize topical therapies. Cleansers emulsify dirt, oil and microorganisms on the skin surface so that they can be easily removed. During cleansing, there is a complex interaction between the cleanser, the moisture skin barrier, and skin pH. Cleansing, with water soap or a liquid cleanser, will affect the moisture skin barrier. Soap will bring about the greatest changes to the barrier and increase skin pH. Liquid facial cleansers are gentler, effecting less disruption of the barrier, with minimal change to skin pH, and can provide people with a cleanser that is a combination of surfactant classes, moisturizers and acidic pH in order to minimize disruption to the skin barrier.

Carcinogenesis, 1998

The Bloom's syndrome gene, BLM, encodes a protein which bears homology to the RecQ helicases. It ... more The Bloom's syndrome gene, BLM, encodes a protein which bears homology to the RecQ helicases. It is believed to be involved in DNA replication and has been implicated in the maintenance of genomic stability. To investigate whether BLM was involved in cellular responses to DNA damage Bloom's syndrome fibroblasts were treated with either UV or ionizing radiation and the levels of p53 and two of its down stream effectors, p21 waf1/cip1 and hdm2, were determined by western blot analysis. Following 20 J/m 2 UVC-radiation we observed that the maximal accumulation of p21 waf1/cip1 and hdm2 proteins preceded that of p53 in both a normal diploid fibroblast cell strain (GM0038) and in two Bloom's syndrome cell strains. Furthermore, the Bloom's syndrome cells demonstrated a delayed and prolonged accumulation of all three proteins and a delayed recovery of the protein levels back to pre-damage levels compared with the normal cell strain. Conversely, normal and Bloom's syndrome cell response following 2.5 Gy of ionizing radiation was quite similar for p21 waf1/cip1 and hdm2, but differed significantly for p53. Maximum accumulation of p53 occurred within 2 h of damage and preceded that of p21 waf1/cip1 and hdm2. These results suggest that the BLM protein may play a role in the detection of certain types of DNA damage and in the cellular response to that damage.

Canadian Journal of Diabetes, 2015

This program has received financial support from no one in the form of anything. • This program h... more This program has received financial support from no one in the form of anything. • This program has received in-kind support from no one in the form of anything.

Canadian journal of kidney health and disease, 2016

Hyponatremia is a recognized complication of congestive heart failure (CHF) and is associated wit... more Hyponatremia is a recognized complication of congestive heart failure (CHF) and is associated with reduced survival. Therefore, early identification and appropriate management of hyponatremia is important. The aim of this study was to determine the general approach amongst Canadian healthcare practitioners and trainees to the identification and management of hyponatremia complicating CHF. Respondents completed 15 multiple-choice style questions in 3 case scenarios regarding the approach to management of hyponatremia complicating CHF using an online survey on UKidney.com between November 2012 and May 2013. Results were presented as a proportion of averaged correct/incorrect responses amongst Canadian nephrologists, cardiologists, internists and trainees in each of two domains; pathophysiology and management. Management was further subdivided into correct and incorrect use of diuretic therapy, hypertonic saline, oral urea tablets, vasopressin receptor antagonists (vaptans) and rate of...

SAGE Open Medicine, 2015

Objective: Allergic rhinitis is a common, usually long-standing, condition that may be self-diagn... more Objective: Allergic rhinitis is a common, usually long-standing, condition that may be self-diagnosed or have a formal diagnosis. Our aim was to identify how allergic rhinitis sufferers self-manage their condition. Methods: A sample of 276 self-identified adult allergy sufferers pooled from social media completed an online survey comprising 13 questions. The survey was fielded by a professional research organization (Lab42). The main outcome measures included the use of prescription and/or non-prescription allergy medication, and interactions with physician and/ or pharmacist with respect to medication use. Results: Of the respondents, 53% (146/276) indicated that they used both prescription and over-the-counter medication to manage their allergy symptoms. Of those who used prescription medication, 53% reported that they discussed their prescription medication in great detail with their physician when it was prescribed, while 42% spoke about it briefly. Following the initial prescription, few discussions about the prescription occur with the physician (45% indicate several discussions, 40% indicate one or two discussions, and 10% indicate no discussions). In most cases (~75% of the time), allergy prescription refills did not require a doctor visit with patients obtaining refills through phone calls to the doctor's office or through the pharmacy. Two-thirds of patients (69%) report that they have discussed their prescription allergy medication with a pharmacist, with greater than half of respondents having discussed the use of the non-prescription medication with their doctor. Conclusion: Patients with diagnosed allergic rhinitis appear to be self-managing their condition with few interactions with their doctor about their allergy prescription. Interactions with a pharmacist about allergy medication (prescription and nonprescription) appear to be more common than interactions with a physician.

Current Oncology, Feb 20, 2015

Guideline questions and recommendations related to the treatment of venous thromboembolism (vte) ... more Guideline questions and recommendations related to the treatment of venous thromboembolism (vte) Category Question Recommendations Strength of evidence Grade Consensus category Preferred therapy and dosing

British Journal of Cancer, 1995

Summ_uxy A point mutation in the mRNA of NADP(H): quinone oxidoreductase 1 (NQOI, DT-diaphorase) ... more Summ_uxy A point mutation in the mRNA of NADP(H): quinone oxidoreductase 1 (NQOI, DT-diaphorase) is believed to be responsible for reduced enzyme activity in the adenocarcinoma BE cell line. The present study examined nine cultured human non-cancerous fibroblast cell strains, five of which were from members of a single cancer-prone family, which demonstrated widely varying activity levels of DT-diaphorase (41-3462 nmol min-'mg-' protein), to determine if genetic alteration of the NQOI or NOQ2 gene was involved in determining enzyme activity. All cell strains expressed NQOI and NQO. mRNA as measured by a quantitative polymerase chain reaction amplification technique. No relationship was found between the level of mRNA expressed and the enzyme activity in the cells. Sequencing of the entire complementary DNA from the cell strains revealed only a single base substitution at nucleotide 609 in one allele encoding NQOI in every cell strain from members of the cancer-prone family, except for one cell strain which expressed only the T at nucleotide 609 in both alleles. Subsequent examination of genomic DNA from 44 individuals revealed that this base substitution is present in approximately 50%0 of the population. The presence of the T at nucleotide 609 in the NQOI locus does not appear to be directly causal for altered DT-diaphorase activity.

Cancer and Metastasis Reviews, 1993

Mitomycin C is being used as an adjunct to ionizing radiation in the treatment of some solid tumo... more Mitomycin C is being used as an adjunct to ionizing radiation in the treatment of some solid tumors. A rationale for this is that radioresistant hypoxic cells in solid tumors will have enhanced sensitivity to this bioreductively activated drug, compared to aerobic cells. The role of oxygen concentration and enzymatic drug reduction in bioreductive drug activation have been investigated. Techniques are reviewed for thein vitro determination of the oxygen concentration dependency of bioreductive drug activation. One of these techniques, an open cell suspension system using Chinese hamster ovary cells, is described. Results are shown that indicate that the oxygen concentration dependency of toxicity of mitomycin C and one of its analogues porfiromycin, though qualitatively complementing the oxygen dependency of ionizing radiation toxicity, are not quantitatively optimal. Using a mitomycin C resistant human cell strain (3437T) from a cancer prone family, a possible role for DT-diaphorase, an oxygen insensitive 2-electron transfer enzyme, is suggested. A correlation between a low level of DT-diaphorase in 3437T cells and mitomycin C resistance under aerobic exposure conditions is seen. Under hypoxic exposure conditions this resistance is lost, suggesting 1-electron transfer enzymes control hypoxic cell bioreductive activation. An activation role for DT-diaphorase in mitomycin C toxicity in the treatment of solid tumors is contrasted to a potential detoxification role for the enzyme with other xenobiotics in the cancer prone family phenotype.

British Journal of Cancer, 1996

A polymorphism in NAD(P)H:quinone oxidoreductase (NQO1): relationship of a homozygous mutation at... more A polymorphism in NAD(P)H:quinone oxidoreductase (NQO1): relationship of a homozygous mutation at position 609 of the NQO1 cDNA to NQO1 activity Sir -NQO1 has attracted considerable attention owing to its ability to deactivate a broad range of xenobiotics while activating certain anti-tumour quinones . A number of recent reports have highlighted the occurrence and potential significance of a point mutation in the NQO1 gene which is associated with a loss of NQO1 activity in both normal and tumour tissue Eickelmann et al., 1994a,b;. The mutation is a C to T point mutation at position 609 of the NQO1 cDNA which codes for a proline to serine substitution in the amino acid sequence of the protein . The mutation was originally characterised in the BE human colon adenocarcinoma cell line by SSCP analysis and sequencing and subsequently in the H596 human non-small-cell lung cancer cell line by a polymerase chain reactionrestriction fragment length polymorphism (PCR-RFLP) technique . Both the BE and H596 cell lines had moderate NQO1 mRNA expression but extremely low or non-detectable NQO1 activity. Purified, recombinant BE and H596 mutant NQO1 proteins expressed in E. coli have residual activity (< 10% of wild-type). While both BE and H596 recombinant mutant proteins reacted with a mouse monoclonal antibody raised against human NQO1, immunoblot analysis of BE and H596 cell lines did not detect NQO1 protein expression . This suggests that in cells the mutant protein may not be made or that the mutant protein may be made but rapidly degraded. Kuehl et al. (1995) have recently examined the relationship between the heterozygous mutation at position 609 and NQO1 activity. These data demonstrate a wide range of NQO1 activity in IC to T heterozygotes and suggests a significant role for post-transcriptional modification in determination of NQO1 activity.