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Heat-inducible promoters for gene therapy
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MOLECULAR
C anat .I
[. . . . . . . . . . . . . . . . . . .
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ii
A major new initiative 'to define th| molecular anatomy of tumour cellsl launched by the US National Cance (NCI; Bethesda, MD, USA). The C Genome Anatomy Project (CGAP) speed the discovery of new diagnos defining the genes and proteins resl; cancer development. The initial pro an index of all the genes expressed cancers, which will be publicly avai Intemet, and new technologies for molecular analysis of tumour specu CGAP is part of NCI's research: improve cancer diagnosis. Cancer ii fundamentally a genetic disease, ani clinicians of the future will probe proteins in a tumour cell for signs o the disease will progress, whether i! spread and what treatments it migh! NCI's Cancer Diagnostics Branch, i the infrastructure, in terms of both s hardware, for this new approach to i molecular analysis of cancer. constructing cDNA libraries fi throughput sequencing of the I tumours of the breast, colon, t~ ovary. Taube explains that, eve input will largely be one of co characterizing tissue samples National Cooperative Human'
MEDICINE
TODAY,
MARCH
1997
Heatinducible promoters for gene therapy The US National Center for Research Resources (NCRR) and US National Institutes of Health (NIH; both in Bethesda, MD, USA) are seeking collaborators to help develop technologies to control local gene expression using a heat shock protein (hsp) promoter. This project aims to overcome one current limitation of gene therapy: how to control when, where and to what extent exogenous genes are expressed. The NCRR has applied for patents 'claiming' the core technology of using a heat-inducible promoter in combination with local heat, preferably provided by magnetic resonance imaging (MRI)-guided focused ultrasound (FUS). It is offering academic and/or commercial organizations opportunities for a Cooperative Research and Development Agreement (CRADA). One of the functions of hsps is to protect organisms against heat-stress; the expression of some hsp genes is affected by changes in temperature. In particular, expression of the gene encoding the heat-inducible hsp70, under control of the hsp70B promoter, shows a strong induction when temperatures in the cell increase by only a few degrees. Researchers led by Chrit Moonen who, until recently, worked at the In vivo NMR Research Center at the NIH, aim to combine this promoter switch with target genes to be introduced in vivo. The construct would have to be delivered to the target cells by a vector, but the target gene would not be expressed in the target site until the temperature was raised locally. The extent to which the gene is expressed could be controlled by the amount the temperature is increased and the time period during which FUS is applied. Recent developments with MRI-guided FUS should allow precise targeting of the locations where the gene of interest is to be expressed. According to Moonen, because FUS can be guided with anatomical and temperature images generated by MILl, it is possible to check whether
m
94
Copyright©1997ElsevierScienceLtd.All rightsreserved.1357- 4310/97/$17.00
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M O L E C U L A R M E D I C I N E TODAY, M A R C H 1997
the local heat is being applied to exactly the correct location. 'This gives the potential for quite beautiful control over the expression of the gene by non-invasive means', he enthuses. Moonen is now setting up an MRI/FUS laboratory in Bordeaux, with the French Centre National de la Recherche Scientifique (CNRS) to continue this research in collaboration with the NIH. A paper to be presented by Moonen and colleagues at the International Society for Magnetic Resonance Imaging meeting (Vancouver, Canada, 12-18 April 1997) will report that MRI-guided FUS can be used to turn on the production of hsp70 in the thigh muscles of rats. Levels of hsp70 increased by a factor of
2-17 in the area targeted by FUS (a few mm2) when the local temperature was raised by 5°C. The next step is to make constructs that combine the hsp promoter with 'useful' target genes, and then to put the combination into a vector. Moonen's team has taken the unusual step of seeking collaborators early on* because it believes that the project covers a broad field of technology with a number of applications. *The investigatorswouldparticularlylike to contact researchers developinggenetherapyvectors and people with ideasfor applicationsof this noveltechnology. For further information,contactChrit Moonenor Tom Ingalls,NCRRBuilding12A/Room4057, Bethesda, MD 20892-2490,USA.
Clearing the lung Genetic susceptibility to lung cancer is one of four research projects attracting a new award to the M.D. Anderson Cancer Center (Houston, TX, USA) and the University of Texas Southwestern Medical Center (UTSMC; Dallas, TX, USA). Lung cancer researchers from both institutions will also use the US $4.5 million 'Specialized Program of Research Excellence' award from the National Cancer Institute (NCI; Bethesda, MD, USA) to study new tumour suppressor genes, detection of genetic damage caused by cigarette smoking, and the efficacy of retinoid drugs in cancer prevention. Gall Tomlinson (Assistant Professor of Pediatrics, UTSMC), who is head of the project on genetic susceptibility,explains how the project will proceed. In the county's hospitals, newly diagnosed lung cancer patients will be asked about their family history of disease and their smoking
e
w
s
'Although a large molecular biology effort is involved, the physics behind the MRI and FUS is by no means trivial,' comments Moonen; 'why re-invent the wheel if other investigators are already addressing important problems such as what vectors to use, potential toxicity and safety problems?' One of their first objectives is the transfer of genes for various lymphokines into experimental animal models using an adenovirus vector. In the first instance, they intend to study the dosage and toxicity of lymphokines produced locally; this could be applied to the treatment of cancer and other diseases. Janet Fricker
over
iiiiiiiil ~
genes
habits. They and aheir family members will also be for b l ~ i ~ p l e s . The research group will 1 ~ at patterns ~ allele loss in chromosomes, says TowJinson, fo~sing in particular on chromosome 3p and 9p, where loss of heterozygosity (indicating missing chunks of DNA presumed to include tumour suppressor genes) has already been shown in most lung tumours. They hope that they will eventually be able to correlate specific genetic markers with the familial occurrence of lung cancer, which would provide a means of testing the population for evidence of a predisposition to contracting the disease. Meanwhile, the same pedigrees can be used in complementary research. Margaret Spitz, also at the M.D. Anderson Cancer Center, will perform mutagen-sensitivity assays on cells from the patients' peripheral blood. Based on her
preliminary evidence that bleomycin causes more breaks in chromosomes from patients with lung cancer than in those from unaffected individuals, the different sensitivities to the mutagen will be correlated with the patient's family history. Tobacco smoke contains trace amounts of dozens of mutagens and, says Tomlinson, the long-term goal is to develop an assay to predict who is most susceptible to the genetic damage that these cause. John Minna (Director of the Center for Therapeutic Oncology Research, UTSMC), who is Co-Principal Investigator on the whole program with Jack Roth (Chairman, Department of Thoracic and Cardiovascular Surgery, M.D. Anderson Cancer Center), will be trying to identify the recessive oncogene from 30 candidate genes that he has located in the relevant region: chromosome 3p21.3. When that gene is found, the pedigrees will be screened to determine whether the gene is a predisposing factor for lung cancer. Another project, run by Adi Gazdar, will look for biomarkers of early processes in lung tumour development; working alongside this project, Minna and Roth will then have a range of cytogenefic and molecular markers to test clinically for their ability to predict lung cancer risk. Members of the pedigrees found to be at risk will also be able to take part in trials of chemopreventive therapies such as retinoids. Claire O'Brien i
Copyright 01997 Elsevier Science Ltd. All rights reserved. 1357 - 4310/97/$17.00
95
e
w
s
MOLECULAR
C anat .I
[. . . . . . . . . . . . . . . . . . .
,
ii
A major new initiative 'to define th| molecular anatomy of tumour cellsl launched by the US National Cance (NCI; Bethesda, MD, USA). The C Genome Anatomy Project (CGAP) speed the discovery of new diagnos defining the genes and proteins resl; cancer development. The initial pro an index of all the genes expressed cancers, which will be publicly avai Intemet, and new technologies for molecular analysis of tumour specu CGAP is part of NCI's research: improve cancer diagnosis. Cancer ii fundamentally a genetic disease, ani clinicians of the future will probe proteins in a tumour cell for signs o the disease will progress, whether i! spread and what treatments it migh! NCI's Cancer Diagnostics Branch, i the infrastructure, in terms of both s hardware, for this new approach to i molecular analysis of cancer. constructing cDNA libraries fi throughput sequencing of the I tumours of the breast, colon, t~ ovary. Taube explains that, eve input will largely be one of co characterizing tissue samples National Cooperative Human'
MEDICINE
TODAY,
MARCH
1997
Heatinducible promoters for gene therapy The US National Center for Research Resources (NCRR) and US National Institutes of Health (NIH; both in Bethesda, MD, USA) are seeking collaborators to help develop technologies to control local gene expression using a heat shock protein (hsp) promoter. This project aims to overcome one current limitation of gene therapy: how to control when, where and to what extent exogenous genes are expressed. The NCRR has applied for patents 'claiming' the core technology of using a heat-inducible promoter in combination with local heat, preferably provided by magnetic resonance imaging (MRI)-guided focused ultrasound (FUS). It is offering academic and/or commercial organizations opportunities for a Cooperative Research and Development Agreement (CRADA). One of the functions of hsps is to protect organisms against heat-stress; the expression of some hsp genes is affected by changes in temperature. In particular, expression of the gene encoding the heat-inducible hsp70, under control of the hsp70B promoter, shows a strong induction when temperatures in the cell increase by only a few degrees. Researchers led by Chrit Moonen who, until recently, worked at the In vivo NMR Research Center at the NIH, aim to combine this promoter switch with target genes to be introduced in vivo. The construct would have to be delivered to the target cells by a vector, but the target gene would not be expressed in the target site until the temperature was raised locally. The extent to which the gene is expressed could be controlled by the amount the temperature is increased and the time period during which FUS is applied. Recent developments with MRI-guided FUS should allow precise targeting of the locations where the gene of interest is to be expressed. According to Moonen, because FUS can be guided with anatomical and temperature images generated by MILl, it is possible to check whether
m
94
Copyright©1997ElsevierScienceLtd.All rightsreserved.1357- 4310/97/$17.00
N
M O L E C U L A R M E D I C I N E TODAY, M A R C H 1997
the local heat is being applied to exactly the correct location. 'This gives the potential for quite beautiful control over the expression of the gene by non-invasive means', he enthuses. Moonen is now setting up an MRI/FUS laboratory in Bordeaux, with the French Centre National de la Recherche Scientifique (CNRS) to continue this research in collaboration with the NIH. A paper to be presented by Moonen and colleagues at the International Society for Magnetic Resonance Imaging meeting (Vancouver, Canada, 12-18 April 1997) will report that MRI-guided FUS can be used to turn on the production of hsp70 in the thigh muscles of rats. Levels of hsp70 increased by a factor of
2-17 in the area targeted by FUS (a few mm2) when the local temperature was raised by 5°C. The next step is to make constructs that combine the hsp promoter with 'useful' target genes, and then to put the combination into a vector. Moonen's team has taken the unusual step of seeking collaborators early on* because it believes that the project covers a broad field of technology with a number of applications. *The investigatorswouldparticularlylike to contact researchers developinggenetherapyvectors and people with ideasfor applicationsof this noveltechnology. For further information,contactChrit Moonenor Tom Ingalls,NCRRBuilding12A/Room4057, Bethesda, MD 20892-2490,USA.
Clearing the lung Genetic susceptibility to lung cancer is one of four research projects attracting a new award to the M.D. Anderson Cancer Center (Houston, TX, USA) and the University of Texas Southwestern Medical Center (UTSMC; Dallas, TX, USA). Lung cancer researchers from both institutions will also use the US $4.5 million 'Specialized Program of Research Excellence' award from the National Cancer Institute (NCI; Bethesda, MD, USA) to study new tumour suppressor genes, detection of genetic damage caused by cigarette smoking, and the efficacy of retinoid drugs in cancer prevention. Gall Tomlinson (Assistant Professor of Pediatrics, UTSMC), who is head of the project on genetic susceptibility,explains how the project will proceed. In the county's hospitals, newly diagnosed lung cancer patients will be asked about their family history of disease and their smoking
e
w
s
'Although a large molecular biology effort is involved, the physics behind the MRI and FUS is by no means trivial,' comments Moonen; 'why re-invent the wheel if other investigators are already addressing important problems such as what vectors to use, potential toxicity and safety problems?' One of their first objectives is the transfer of genes for various lymphokines into experimental animal models using an adenovirus vector. In the first instance, they intend to study the dosage and toxicity of lymphokines produced locally; this could be applied to the treatment of cancer and other diseases. Janet Fricker
over
iiiiiiiil ~
genes
habits. They and aheir family members will also be for b l ~ i ~ p l e s . The research group will 1 ~ at patterns ~ allele loss in chromosomes, says TowJinson, fo~sing in particular on chromosome 3p and 9p, where loss of heterozygosity (indicating missing chunks of DNA presumed to include tumour suppressor genes) has already been shown in most lung tumours. They hope that they will eventually be able to correlate specific genetic markers with the familial occurrence of lung cancer, which would provide a means of testing the population for evidence of a predisposition to contracting the disease. Meanwhile, the same pedigrees can be used in complementary research. Margaret Spitz, also at the M.D. Anderson Cancer Center, will perform mutagen-sensitivity assays on cells from the patients' peripheral blood. Based on her
preliminary evidence that bleomycin causes more breaks in chromosomes from patients with lung cancer than in those from unaffected individuals, the different sensitivities to the mutagen will be correlated with the patient's family history. Tobacco smoke contains trace amounts of dozens of mutagens and, says Tomlinson, the long-term goal is to develop an assay to predict who is most susceptible to the genetic damage that these cause. John Minna (Director of the Center for Therapeutic Oncology Research, UTSMC), who is Co-Principal Investigator on the whole program with Jack Roth (Chairman, Department of Thoracic and Cardiovascular Surgery, M.D. Anderson Cancer Center), will be trying to identify the recessive oncogene from 30 candidate genes that he has located in the relevant region: chromosome 3p21.3. When that gene is found, the pedigrees will be screened to determine whether the gene is a predisposing factor for lung cancer. Another project, run by Adi Gazdar, will look for biomarkers of early processes in lung tumour development; working alongside this project, Minna and Roth will then have a range of cytogenefic and molecular markers to test clinically for their ability to predict lung cancer risk. Members of the pedigrees found to be at risk will also be able to take part in trials of chemopreventive therapies such as retinoids. Claire O'Brien i
Copyright 01997 Elsevier Science Ltd. All rights reserved. 1357 - 4310/97/$17.00
95