- Email: [email protected]
Philip D. Lawley (1927–2011)
Mutation Research 732 (2012) 1–2
Contents lists available at SciVerse ScienceDirect
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis journal homepage: www.elsevier.com/locate/molmut Community address: www.elsevier.com/locate/mutres
Obituary
Philip D. Lawley (1927–2011)
Photo by Francis L. Martin. By showing that DNA is the target for chemical carcinogens, Philip Lawley laid the foundation for the now universally accepted idea that cancer is a genetic disease arising by somatic mutation. This was a major advance in understanding carcinogenesis at a time – the 1960s – when proteins were thought to be the primary target. Philip Lawley was born in 1927 in Abbots Bromley in Staffordshire to parents who were teachers. He obtained a degree in Chemistry in 1949 at Oxford University and a PhD at Nottingham University where he studied the physicochemical properties of DNA including the first investigation of what later became known as DNA denaturation. He joined the Chester Beatty Research Institute (CBRI) – now the Institute of Cancer Research (ICR) – in Fulham Road, London in 1953 (the year in which Watson and Crick revealed the double-helical structure of DNA). Here he undertook studies of the interaction with DNA of carcinogenic and mutagenic alkylating agents such as nitrogen mustard. In 1957 Lawley reported [1] results of experiments, using paper chromatography and UVspectroscopy, in which he had reacted dimethyl sulphate with each of the 4 DNA bases and deoxyribonucleotides, and nitrogen mustard with calf thymus DNA. He showed that the order of reactivity with dimethyl sulphate was G > A > C > T and that nitrogen mustard produced 7-alkylguanine and 3 other unidentified products when reacted with DNA. He predicted that mustards could crosslink DNA via alkylation of purines and pyrimidines. His further studies
0027-5107/$ – see front matter doi:10.1016/j.mrfmmm.2012.02.003
confirmed that nucleophilic centres in DNA bases could react with electrophilic atoms in alkylating agents to form chemically stable DNA adducts, a heterodox view at a time when weak and reversible reactions of carcinogens with DNA were thought to predominate. By the late 1950s Lawley had started his collaboration with Peter Brookes (another chemist), their different talents, skills and personalities making them a formidable combination. So far they had used physicochemical methods for detecting DNA adducts and realized that more sensitive techniques would be required to detect them at the levels expected in vivo. At this time the state-owned Radiochemical Centre in Amersham, Buckinghamshire, was producing radiolabelled chemicals, including 35 S-labelled mustard gas. Mustard gas (a mutagen and carcinogen) was used as a chemical weapon in the 1914–1918 war (Lawley’s father had been exposed to it while serving in the trenches) and is the archetype of bifunctional alkylating anti-tumour drugs such as nitrogen mustard, chlorambucil and melphalan which were developed in the 1960s and are still used. The idea of handling even small amounts of radiolabelled mustard gas in central London provoked alarm and therefore Lawley and Brookes moved from the CBRI in London to the Institute’s Pollards Wood Research Station to conduct their studies. These laboratories were set in 60 acres of woodland conveniently close to the Radiochemical Centre, and were clustered around a mock-Tudor country house that once belonged to the Bertram Mills circus family. It was in these leafy and peaceful surroundings that Lawley and Brookes produced their seminal work on the binding of mutagens and carcinogens to DNA. In a classic paper published in 1960 [2] they described how they applied [35 S]-mustard gas to purified nucleic acids, to a plant virus, to bacteria, and to mouse tumour cells in vitro and in vivo. They obtained quantitative data on the level and kinetics of DNA binding in these different targets and showed that mustard gas formed an adduct with N-7 atom of guanine which they confirmed by chemical synthesis. Further studies with bifunctional mustards showed that they cross-linked the opposing strands of the DNA helix, hindering DNA replication and cell division, which explained their extreme toxicity to dividing cells. They characterised the crosslinked diguaninyl adduct of mustard gas and showed that it was enzymatically removed from the DNA of bacteria resistant to its toxicity, but not from DNA of sensitive bacteria. This was probably the first quantitative demonstration of the repair of specific lesions in DNA damaged by a carcinogen in a living organism. It is now clear, 50 years on, that many of the genes mutated in human cancer are involved in DNA repair. In a second landmark paper published in Nature [3] they reported a quantitative relationship between carcinogenicity and DNA binding in a series of polycyclic aromatic hydrocarbons (PAHs).
2
Obituary / Mutation Research 732 (2012) 1–2
These ubiquitous products of incomplete combustion (found, for example, in tobacco smoke) are chemically inert, but many are potent carcinogens following their metabolic activation to electrophiles. They observed that the carcinogenic potency of the PAHs was positively correlated with the degree of DNA binding in mouse skin, but not with binding to protein or RNA. This seminal discovery overturned the prevailing view that proteins were the critical cellular targets for carcinogens and changed the course of cancer research. Lawley went on to show how point mutations (transitions and transversions) are induced by miscoding when potent alkylating mutagens (such as N-methyl-N-nitrosourea) react with those atoms in DNA (such as O-6 of guanine) that determine base-pairing during DNA replication. Point mutations are now known to occur frequently in a variety of human cancer genes. He also discovered the O-6-methylguanine-DNA methyltransferase DNA-repair system that selectively reverses such DNA modifications. Philip Lawley’s modest exterior concealed a piercing intellect, deep scholarship, a prodigious memory, liberal views, iron-clad integrity and mordant wit. The following is a typically wry comment. Writing in Current Contents in 1990 [4] about his Citation Classic “Some chemical aspects of dose–response relationships in alkylation mutagenesis” [5], he observed “This publication is based on a paper presented . . .. at Bad Krozingen. I recall being very impressed with the definitely modern but pleasant splendour of the conference venue, which appeared to be devoted to the welfare of the German old-age pensioner desirous of ‘taking the waters’ at a typical spa, and manifestly superior to anything on offer to his British counterpart”. An example of Lawley’s wide knowledge, informed scepticism and trenchant style can be found in an account [6] of a 1979 NATO meeting on cancer and in vitro screening in which he ranges from Galen, via Ramazzini to Susan Sontag in his critique of the relevance of the Ames test to human cancer. His outstanding contribution to the landmark 2-volume 1984 publication Chemical Carcinogens, Second Edition [7] exemplifies his scholarship – his 160-page chapter “Carcinogenesis by Alkylating Agents” is a tour de force. In 1989 he published [8] a personal account of the early work on reactions of mutagens and carcinogens with DNA. His 1994 review ‘From fluorescence spectra to mutational spectra, a historical overview of DNAreactive compounds’ [9] describes the history of this field, the emergence of current concepts and Lawley’s contribution to them. Philip Lawley was a bench scientist who did not follow scientific fashion and was happiest working with just one or two trusted colleagues. He wrote concise and elegant prose, in longhand, standing at a table piled with papers. When that table was full he moved to another, and another, until the paper was completed. He took great pleasure in conversation and often engaged in protracted and sometimes heated debate with whoever happened to be around – usually a scientific colleague, but occasionally an innocent bystander – sometimes losing track of time. At Pollards Wood,
these conversations would often continue al fresco in the coppiced beech woods, sometimes in the company of Lawley’s whippet. His conversations were garnished with his interests other than science, including jazz, painting, reading, politics, dogs, and old trams. He was awarded a DSc in 1975; the title of Professor of Chemical Carcinogenesis was conferred by the University of London in 1983. He received the European Environmental Mutagen Society Award in 1987 and was made a Fellow of the United Kingdom Environmental Mutagen Society in 1990 and an Associate Member of the ICR in 2002. In January 2003 the ICR honoured the achievements of Brookes and Lawley by naming a £21 million laboratory after them. This is located in the Royal Marsden Hospital site in Sutton, South London. Philip Lawley officially retired in 1992, but continued to work in the Haddow Laboratories at Sutton, at the bench, for several more years, enriching the lives of those who worked with and alongside him with his knowledge, congenial company and wit. He was devoted to his family, and is survived by Pauline, his wife, his daughter Fiona, his sons Guy and Hugh, and grandchildren Beatrix, Baxter, Xabier and Valentin. References [1] P.D. Lawley, The relative reactivities of deoxyribonucleotides and of the bases of DNA towards alkylating agents, Biochim. Biophys. Acta 26 (1957) 450–451. [2] P. Brookes, P.D. Lawley, The reaction of mustard gas with nucleic acids in vitro and in vivo, Biochem. J. 77 (1960) 478–484. [3] P. Brookes, P.D. Lawley, Evidence for the binding of polynuclear aromatic hydrocarbons to the nucleic acids of mouse skin: relation between carcinogenic power of hydrocarbons and their binding to DNA, Nature 202 (1964) 781–784. [4] P.D. Lawley, Trying to correlate chemistry and biology, Curr. Contents 21 (1990) 18. [5] P.D. Lawley, Some chemical aspects of dose–response relationships in alkylation mutagenesis, Mutat. Res. 23 (1974) 283–295. [6] P.D. Lawley, Rapid screening of carcinogens – the end of the beginning? Nature 282 (1979) 134–135. [7] P.D. Lawley, Carcinogenesis by alkylating agents, in: C.E. Searle (Ed.), Chemical Carcinogens, 2nd ed., American Chemical Society, Washington, DC, 1984, pp. 325–484. [8] P.D. Lawley, Mutagens as carcinogens: development of current concepts, Mutat. Res. 213 (1989) 3–25. [9] P.D. Lawley, From fluorescence spectra to mutational spectra, a historical overview of DNA-reactive compounds, IARC Sci. Publ. 125 (1994) 3–22.
Stan Venitt ∗ David H. Phillips Analytical and Environmental Sciences Division, School of Biomedical Sciences, King’s College London, 150 Stamford Street, London SE1 9NH, UK ∗ Corresponding author. E-mail addresses: [email protected] (S. Venitt), [email protected] (D.H. Phillips)
11 February 2012 Available online 28 February 2012
Contents lists available at SciVerse ScienceDirect
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis journal homepage: www.elsevier.com/locate/molmut Community address: www.elsevier.com/locate/mutres
Obituary
Philip D. Lawley (1927–2011)
Photo by Francis L. Martin. By showing that DNA is the target for chemical carcinogens, Philip Lawley laid the foundation for the now universally accepted idea that cancer is a genetic disease arising by somatic mutation. This was a major advance in understanding carcinogenesis at a time – the 1960s – when proteins were thought to be the primary target. Philip Lawley was born in 1927 in Abbots Bromley in Staffordshire to parents who were teachers. He obtained a degree in Chemistry in 1949 at Oxford University and a PhD at Nottingham University where he studied the physicochemical properties of DNA including the first investigation of what later became known as DNA denaturation. He joined the Chester Beatty Research Institute (CBRI) – now the Institute of Cancer Research (ICR) – in Fulham Road, London in 1953 (the year in which Watson and Crick revealed the double-helical structure of DNA). Here he undertook studies of the interaction with DNA of carcinogenic and mutagenic alkylating agents such as nitrogen mustard. In 1957 Lawley reported [1] results of experiments, using paper chromatography and UVspectroscopy, in which he had reacted dimethyl sulphate with each of the 4 DNA bases and deoxyribonucleotides, and nitrogen mustard with calf thymus DNA. He showed that the order of reactivity with dimethyl sulphate was G > A > C > T and that nitrogen mustard produced 7-alkylguanine and 3 other unidentified products when reacted with DNA. He predicted that mustards could crosslink DNA via alkylation of purines and pyrimidines. His further studies
0027-5107/$ – see front matter doi:10.1016/j.mrfmmm.2012.02.003
confirmed that nucleophilic centres in DNA bases could react with electrophilic atoms in alkylating agents to form chemically stable DNA adducts, a heterodox view at a time when weak and reversible reactions of carcinogens with DNA were thought to predominate. By the late 1950s Lawley had started his collaboration with Peter Brookes (another chemist), their different talents, skills and personalities making them a formidable combination. So far they had used physicochemical methods for detecting DNA adducts and realized that more sensitive techniques would be required to detect them at the levels expected in vivo. At this time the state-owned Radiochemical Centre in Amersham, Buckinghamshire, was producing radiolabelled chemicals, including 35 S-labelled mustard gas. Mustard gas (a mutagen and carcinogen) was used as a chemical weapon in the 1914–1918 war (Lawley’s father had been exposed to it while serving in the trenches) and is the archetype of bifunctional alkylating anti-tumour drugs such as nitrogen mustard, chlorambucil and melphalan which were developed in the 1960s and are still used. The idea of handling even small amounts of radiolabelled mustard gas in central London provoked alarm and therefore Lawley and Brookes moved from the CBRI in London to the Institute’s Pollards Wood Research Station to conduct their studies. These laboratories were set in 60 acres of woodland conveniently close to the Radiochemical Centre, and were clustered around a mock-Tudor country house that once belonged to the Bertram Mills circus family. It was in these leafy and peaceful surroundings that Lawley and Brookes produced their seminal work on the binding of mutagens and carcinogens to DNA. In a classic paper published in 1960 [2] they described how they applied [35 S]-mustard gas to purified nucleic acids, to a plant virus, to bacteria, and to mouse tumour cells in vitro and in vivo. They obtained quantitative data on the level and kinetics of DNA binding in these different targets and showed that mustard gas formed an adduct with N-7 atom of guanine which they confirmed by chemical synthesis. Further studies with bifunctional mustards showed that they cross-linked the opposing strands of the DNA helix, hindering DNA replication and cell division, which explained their extreme toxicity to dividing cells. They characterised the crosslinked diguaninyl adduct of mustard gas and showed that it was enzymatically removed from the DNA of bacteria resistant to its toxicity, but not from DNA of sensitive bacteria. This was probably the first quantitative demonstration of the repair of specific lesions in DNA damaged by a carcinogen in a living organism. It is now clear, 50 years on, that many of the genes mutated in human cancer are involved in DNA repair. In a second landmark paper published in Nature [3] they reported a quantitative relationship between carcinogenicity and DNA binding in a series of polycyclic aromatic hydrocarbons (PAHs).
2
Obituary / Mutation Research 732 (2012) 1–2
These ubiquitous products of incomplete combustion (found, for example, in tobacco smoke) are chemically inert, but many are potent carcinogens following their metabolic activation to electrophiles. They observed that the carcinogenic potency of the PAHs was positively correlated with the degree of DNA binding in mouse skin, but not with binding to protein or RNA. This seminal discovery overturned the prevailing view that proteins were the critical cellular targets for carcinogens and changed the course of cancer research. Lawley went on to show how point mutations (transitions and transversions) are induced by miscoding when potent alkylating mutagens (such as N-methyl-N-nitrosourea) react with those atoms in DNA (such as O-6 of guanine) that determine base-pairing during DNA replication. Point mutations are now known to occur frequently in a variety of human cancer genes. He also discovered the O-6-methylguanine-DNA methyltransferase DNA-repair system that selectively reverses such DNA modifications. Philip Lawley’s modest exterior concealed a piercing intellect, deep scholarship, a prodigious memory, liberal views, iron-clad integrity and mordant wit. The following is a typically wry comment. Writing in Current Contents in 1990 [4] about his Citation Classic “Some chemical aspects of dose–response relationships in alkylation mutagenesis” [5], he observed “This publication is based on a paper presented . . .. at Bad Krozingen. I recall being very impressed with the definitely modern but pleasant splendour of the conference venue, which appeared to be devoted to the welfare of the German old-age pensioner desirous of ‘taking the waters’ at a typical spa, and manifestly superior to anything on offer to his British counterpart”. An example of Lawley’s wide knowledge, informed scepticism and trenchant style can be found in an account [6] of a 1979 NATO meeting on cancer and in vitro screening in which he ranges from Galen, via Ramazzini to Susan Sontag in his critique of the relevance of the Ames test to human cancer. His outstanding contribution to the landmark 2-volume 1984 publication Chemical Carcinogens, Second Edition [7] exemplifies his scholarship – his 160-page chapter “Carcinogenesis by Alkylating Agents” is a tour de force. In 1989 he published [8] a personal account of the early work on reactions of mutagens and carcinogens with DNA. His 1994 review ‘From fluorescence spectra to mutational spectra, a historical overview of DNAreactive compounds’ [9] describes the history of this field, the emergence of current concepts and Lawley’s contribution to them. Philip Lawley was a bench scientist who did not follow scientific fashion and was happiest working with just one or two trusted colleagues. He wrote concise and elegant prose, in longhand, standing at a table piled with papers. When that table was full he moved to another, and another, until the paper was completed. He took great pleasure in conversation and often engaged in protracted and sometimes heated debate with whoever happened to be around – usually a scientific colleague, but occasionally an innocent bystander – sometimes losing track of time. At Pollards Wood,
these conversations would often continue al fresco in the coppiced beech woods, sometimes in the company of Lawley’s whippet. His conversations were garnished with his interests other than science, including jazz, painting, reading, politics, dogs, and old trams. He was awarded a DSc in 1975; the title of Professor of Chemical Carcinogenesis was conferred by the University of London in 1983. He received the European Environmental Mutagen Society Award in 1987 and was made a Fellow of the United Kingdom Environmental Mutagen Society in 1990 and an Associate Member of the ICR in 2002. In January 2003 the ICR honoured the achievements of Brookes and Lawley by naming a £21 million laboratory after them. This is located in the Royal Marsden Hospital site in Sutton, South London. Philip Lawley officially retired in 1992, but continued to work in the Haddow Laboratories at Sutton, at the bench, for several more years, enriching the lives of those who worked with and alongside him with his knowledge, congenial company and wit. He was devoted to his family, and is survived by Pauline, his wife, his daughter Fiona, his sons Guy and Hugh, and grandchildren Beatrix, Baxter, Xabier and Valentin. References [1] P.D. Lawley, The relative reactivities of deoxyribonucleotides and of the bases of DNA towards alkylating agents, Biochim. Biophys. Acta 26 (1957) 450–451. [2] P. Brookes, P.D. Lawley, The reaction of mustard gas with nucleic acids in vitro and in vivo, Biochem. J. 77 (1960) 478–484. [3] P. Brookes, P.D. Lawley, Evidence for the binding of polynuclear aromatic hydrocarbons to the nucleic acids of mouse skin: relation between carcinogenic power of hydrocarbons and their binding to DNA, Nature 202 (1964) 781–784. [4] P.D. Lawley, Trying to correlate chemistry and biology, Curr. Contents 21 (1990) 18. [5] P.D. Lawley, Some chemical aspects of dose–response relationships in alkylation mutagenesis, Mutat. Res. 23 (1974) 283–295. [6] P.D. Lawley, Rapid screening of carcinogens – the end of the beginning? Nature 282 (1979) 134–135. [7] P.D. Lawley, Carcinogenesis by alkylating agents, in: C.E. Searle (Ed.), Chemical Carcinogens, 2nd ed., American Chemical Society, Washington, DC, 1984, pp. 325–484. [8] P.D. Lawley, Mutagens as carcinogens: development of current concepts, Mutat. Res. 213 (1989) 3–25. [9] P.D. Lawley, From fluorescence spectra to mutational spectra, a historical overview of DNA-reactive compounds, IARC Sci. Publ. 125 (1994) 3–22.
Stan Venitt ∗ David H. Phillips Analytical and Environmental Sciences Division, School of Biomedical Sciences, King’s College London, 150 Stamford Street, London SE1 9NH, UK ∗ Corresponding author. E-mail addresses: [email protected] (S. Venitt), [email protected] (D.H. Phillips)
11 February 2012 Available online 28 February 2012