Note: Descriptions are shown in the official language in which they were submitted.
CA 02500213 1994-05-10
'~
GENE TRANSFER INTO PANCREATIC
AND B~LIARY EPITI~~~rL CELLS
TECI~I~,CAL FIELD OF THE INVENTION
The present invention relates to methods for
selective somatic gene transfer into a patient s
pancreatic or biliary epithelial cells. The methods of
this invention comprise introducing the gene to be
transferred, associated with an appropriate transfer
vehicle, into the ductal system of either the pancreas
or liver. More specifically, the invention relates to
using these techniques to treat genetic diseases, such
as cystic fibrosis, which are characterized by genetic
defects in those epithelial cells.
BACKGROUND OF THE INVENTION
The epithelial cells lining the ducts of the
liver and the pancreas (both endocrine and exocrine)
are responsible for synthesizing numerous proteins
which are important in maintaining proper functioning
of those organs and homeostasis in general. Diseases
which cause defects in the genes that encode these
proteins can cause serious, and sometimes fatal,
effects.
For example, cystic fibrosis (CF) is a
disease characterized by abnormalities in water and
electrolyte transport into and out of cells. The gene
responsible for CF, the cystic fibrosis transmembrane
:.
conductance regulator gene (CFTR), is known to be
defective in the epithelial cells of CF patients.
While the primary site of damage in CF
patients is the lung epithelia, both the pancreatic and
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bile duct epithelia are also affected [T. F. Boat et
al., in Tie Metabolic Basis of Inherited Disease - 6th
Edition , C. R. Scriver et al., eds., McGraw-Hill, New .
York, pp. 2649-80 (1989)].
Other diseases characterized by genetic
defects in liver and pancreatic epithelial cells are
gallstones (cholelithiasis), ascending sclerosing
cholangitis, primary biliary cirrhosis and diabetes
mellitus.
The treatment of the above-described diseases
is of great importance. One exciting approach is the
use of gene replacement therapy to insert functional
copies of defective genes directly into the affected
cells.
The idea of gene replacement therapy was born
out of the successful transfer of genes into mammalian
cells in culture. The best known method of gene
transfer is achieved by treating mammalian cells with a
coprecipitate of calcium phosphate and the nucleic acid
sequence to be transferred. Mammalian cells take up
this precipitate via endocytosis and some of those
cells can then express the polypeptide encoded by the
nucleic acid sequence. Unfortunately, this technique
is limited to ~ vitro cell cultures and does not have
much utility in treating a patient in vivo. This is
due to the insoluble nature of the nucleic acids and
the low efficiency with which the cells of the body
take up these precipitates.
Other techniques, such as the use of viruses
or liposomes to carry the nucleic acids to the target
cells have more applicability irk vivo [C. Nicolau et
al., Meth. Enzymo~, 149, pp. 157-76 (1987)]. But
these methods also suffer from shortcomings. Most
importantly, neither of these techniques is specific w
for any particular cell type -- rendering it difficult
to deliver the gene of interest to the proper cells via
standard routes of administration.
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Recently, a method of cell specific gene
transfer utilizing nucleic acids conjugated to cell
receptor ligands has been described [United States
- patent 5,166,320]. While this method provides the cell
specificity necessary for 'fir vivo gene therapy, it also
involves additional costs and manipulations in creating
the nucleic acid-ligand conjugates.
Applicant s copending application Serial No.
584,275, filed September 18, 1990, now United States
patent 5,240,846, describes a method of utilizing gene
therapy to treat cystic fibrosis. The application
describes a number of different gene delivery systems
and a number of delivery methods, specifically,
inhalation, injection and ingestion. The application
is specifically directed to treatment of lung
epithelia, but briefly refers to treating pancreatic
and biliary epithelial. cells. Howwer, the application
does not demonstrate that any of the described methods
for treating lung epithelia would be effective or
specific for pancreatic and biliary epithelia.
Accordingly, there is still a need for an
inexpensive and relatively easy way of achieving cell-
specific gene transfer to the epithelial cells ~of the
liver and pancreas.
SUMMARY OF THE INVENTION
The present invention fulfills this need by
providing a novel technique for sir,, vivo gene transfer
into pancreatic and biliary epithelial cells.
Applicant has discovered that administration
of the gene to be transferred, when associated with an
appropriate transfer vehicle, into the ductal system of
either the pancreas or liver causes surprisingly
selective uptake by the epithelial cells lining the
duct. The administration of the gene can be achieved
by methods currently used for injecting contrast dyes
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,,
' -4-
into those ducts for imaging techniques.
The methods of this invention are effective
in treating primary diseases of the liver and pancreas ;
which are characterized by genetic defects in the
epithelia of the organ ductal systems. These genetic
defects include both failure of the cells to express a
sufficient level of polypeptide, as well as the
overproduction of a polypeptide. Such diseases include
cystic fibrosis, which affects these cells, as well as
lung epithelia.
In another embodiment, the invention provides
a method of transferring genes into hepatocytes,
pancreatic islet cells and pancreatic acinar cells. ,
When the concentration of the transfer vehicle
associated with the gene to be transferred is
sufficiently high, these additional cells, as well as
ductal epithelial cells; take up and express the gene.
This represents the first method of achieving gene
transfer into hepatocytes without injection into the
bloodstream. It also represents the first method for
achieving gene transfer into pancreatic islet and
acinar cells.
The methods of this invention advantageously
lower the risks associated with gene transfer by being
cell-specific and by avoiding contact with the
patient's bloodstream. These methods also take
advantage of the anatomical constraints offered by
using the ductal system of the liver and the pancreas,
thus avoiding unwanted gene transfer into other organs
and other cells. And the methods of this invention
offer an additional advantage of allowing excess
genetic material and associated transfer vehicle to be
delivered immediately into the duodenum and excreted in
the stool.
~
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4a
There is thus described'use of a carrier capable
of transferring a functional gene into pancreatic ductal
epithelial cells, for introducing said functional gene into
said pancreatic ductal epithelial cells of a patient via the
interlobular ducts of the pancreas, wherein said functional
gene is associated with the carrier.
There is also described use of a carrier capable
of transferring a functional gene into pancreatic ductal
epithelial cells, wherein the functional gene is associated
with the carrier, for introducing the gene into pancreatic
ductal epithelial cells via the interlobular ducts of the
pancreas of a patient having a pancreatic disease treatable
by the functional gene, thereby treating said pancreatic
disease.
There is also described use of a carrier capable
of transferring a functional gene into biliary epithelial
cells for introducing said functional gene into the biliary
epithelial cells of a patient via the common bile duct,
wherein said functional gene is associated with the carrier
and wherein, if the carrier comprises a virus, then the
functional gene is carried inside the virus.
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BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic representation of the
structure of pAd.CMV-lacZ.
Figure 2 is a schematic representation of the
structure of pAd.CB-CFTR.
Figure 3 depicts the hybridization of a human
CFTR-specific DNA probe to ~ba,I-digested total cellular
DNA from both Ad. CB-CFTR-infected and mock-infected
cells derived from a pancreatic adenocarcinoma of a
patient with CF.
Figure 4 depicts the hybridization of a human
CFTR-specific DNA probe to total cellular RNA from both ,
Ad. CB-CFTR-infected and mock-infected cells derived
from a pancreatic adenocarcinoma of a patient with CF.
Figure 5, panels A and 8, depict the
localization of CFTR in Ad. CB-CFTR-infected cells
derived from a pancreatic adenocarcinoma of a patient
with CF by immunofluorescence using either a non-
reactive antibody (panel A) or a CFTR-specific antibody
(panel B) and a second, FITC-labelled anti-IgG
antibody.
Figure 6, panels A-E depict the distribution
of B-galactosidase in a liver section of a rat at
various times after infection with a low concentration
of either Ad.CB-CFTR or Ad.CMV-lacZ using X-gal
cytochemistry.
Figure ?, panels A-D, depict the presence of
human or rat CFTR RNA in a liver section of a rat 3
days after infection with a low concentration of either
Ad.CB-CFTR or Ad.CMV-lacZ by hybridization to a
t- labelled CFTR-specific probes.
Figure 8, panels A-D depict the distribution
of CFTR and cytokeratin-18 in a liver section of a rat
3 days after infection with a low concentration of
Ad. CB-CFTR or Ad.CMV-lacZ by double immunodiffusion
using antibodies specific for both proteins.
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1~ETAILED DESCRIPTION OF THE INVENTION
The present invention provides methods for
introducing a functional gene into the pancreatic or
biliary ductal epithelial cells of a patient. The term
"functional gene" as used herein, refers to a gene that
encodes a polypeptide and which can be expressed by the
target cell. The term also includes antisense nucleic
acids which are capable of binding to and inhibiting -
the expression of a polypeptide. The term "target
cell" refers to the cell or cell type which takes up
the gene of interest.
The methods of this invention comprise the
step of introducing a gene into the ductal system of
either the pancreas or the liver. In order to
effectuate gene transfer, the gene to be transferred
must be associated with a carrier or vehicle capable of
transducing the epithelial cells of the organ. The
terms "transfer vehicle" and "carrier" refer to any
type of structure which is capable of delivering the
gene of interest to a target cell.
Many such carriers are known in the art. For
example, various viruses that are capable of infecting
epithelial cells can be recombinantly manipulated to
carry the gene of interest without affecting their
infectivity. As used in this application, the terms
"infect" and "infectivity" refer only to the ability of
a virus to transfer genetic material to a target cell.
Those term do not mean that the virus is capable of
replication in the target cell. In fact, it is
preferable that such viruses are replication defective -t
so that target cells do not suffer the effect of viral
replication.
More preferably, the virus employed to carry
the gene in the methods of this invention is a
recombinant adenovirus. Adenovirus is preferred for
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its ability to infect non-dividing or slowly dividing
cells, such as epithelia. Most preferably, the
recombinant adenovirus is a derivative of AdS, which
has the sequences spanning the E1 region deleted and
replaced with a promoter, with or without additional
' enhancer sequences, and the gene to be transferred.
Any promoter which will provide constitutive expression
of the gene once incorporated into the target cell
genome may be employed. Examples of such promoters are
Rous sarcoma virus promoters, Maloney virus LTRs,
promoters endogenous to the target cell and
cytomegalovirus (CMV) promoters. Preferred promoters
are the 13-actin promoter and the CMV promoters.
Example of preferred enhancer sequences which may be
employed in these recombinant adenoviruses include
those found in the CMV genome, especially those from
the immediate early region of the genome, and alpha
fetal protein enhancer sequences.
Other viruses that may be used as transfer
vehicles in the methods of this invention are
replication defective retroviruses. When these
replication defective retroviruses are employed, their
genomes can be packaged by a helper virus in accordance
with well-known techniques. Suitable retroviruses
include PLJ, pZip, pWe and pEM, each of which is well
known in the art. Suitable helper viruses for
packaging genomes include ~YCrip, ~YCre, ~Y2, ~YAm and
Adeno-associated viruses.
Gene delivery systems other than viruses can
also be employed in the methods of this invention. For
example, the gene to be transferred may be packaged in
._ a liposome. When cells are incubated with DNA-
encapsidated liposomes, they take up the DNA and
express it. To form these liposomes, one mixes the DNA
of an expression vector which expresses the gene to be
transferred with lipid, such as N-(1-(2,3,-
dioleyloxy)propyl]-N,N,N-trimethylammonium chloride
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(DOTMA) in a suitable buffer, such as Hepes buffered
saline. This causes the spontaneous formation of
lipid-DNA complexes (liposomes) which can be employed .
in the methods of this invention [P. L. Felgner et al.,
Proc. Natl. Acad. Sci. USA, 84, pp. 7413-17 (1987)].
Another gene delivery system that may be
utilized in this invention is DNA-protein complexes.
The formation of these complexes is described in United
States patent 5,166,320,
l0 Specifically, these
complexes comprise the gene to be transferred (together
with promoter, enhancer sequences and other DNA
necessary for expression in the target cell) linked via
a suitable polymer, such as polylysine, to a
polypeptide ligand for a receptor on the liver or
pancreatic epithelial cell surface. This complex is
taken up by the epithelial cells via endocytosis after
the ligand binds to the cell surface receptor. The DNA
is then cleaved from the rest of the complex via
intracellular enzymes which cut the polymer linker.
Once the gene to be transferred is associated
with a suitable transfer vehicle, it must be introduced
into the ductal system of either the liver or pancreas.
For the liver, the preferred route of administration is
through the common bile duct. For the pancreas, the
preferred route is through the pancreatic duct. In
either case, the genetic material may be delivered to
the desired ductal system through the bowel. If only
one of the two organs is the desired target, the other
can be blocked off by ligature at the point where the
duct empties into the bowel.
Any medically accepted method for inserting
material into the ducts of these organs can be utilized
in this invention. Preferably, the technique employed
is minimally invasive and employs a retrograde filling
of the ducts. One such preferred technique is the
endoscopic retrograde cholangiography procedure (FRCP):
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FRCP is currently employed to visualize the biliary and
pancreatic ductal systems by cannulating the common
bile duct or pancreatic duct via an endoscope and
injecting contrast dye. In the methods of this
invention the gene to be transferred and its associated
transfer vehicle is substituted for the dye. Other
methods for inserting the gene of interest into the
target organs include surgical implantation and
insertion via a laparoscope.
According to a preferred embodiment, the
invention provides a method for treating pancreatic and
biliary diseases using the technique of somatic gene
transfer. Various diseases are known to be associated
with genetic defects of the pancreatic and biliary
epithelia. In addition, certain symptoms of various
diseases of the liver or pancreas are manifest by the
epithelial cells of those organs. For example,
inflammation of the pancreas or liver could be
inhibited by the methods of this invention if used to
transfer cytokine genes into the epithelia. Also,
liver diseases that cause proliferation of biliary
epithelia could be treated by the gene therapy methods
of this invention when utilized to deliver a growth
inhibitory genes to those cells. Examples of some of
the other diseases that may be treated by the methods
of this invention include ascending sclerosing
cholangitis and primary biliary sclerosis.
According to a more preferred embodiment, the
disease to be treated by the methods of this invention
is CF. CF is a disease that exerts its primary effect
on the lung airway epithelia. However, the disease
also affects pancreas and liver epithelia. These
secondary disease sites are becoming more important as
various therapies to treat CF diseased lungs are
developed.
CF can lead to cholestasis, jaundice and
eventually cirrhosis in the liver and pancreatitis and
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malabsorption in the pancreas. Current treatment of
CF-related pancreas disorders involves enzyme
replacement therapy. However, patients still suffer
from pancreatitis and associated malnutrition. There
is no current treatment for CF-related liver disorders.
The defective gene in CF is the cystic
fibrosis transmembrane conductance regulator (CFTR), a
purported transmembrane chloride channel. CFTR
expression in the liver has been localized to the
epithelial cells which line the biliary tract. In the
pancreas, the cells that line the ducts of the exocrine
pancreas appear to be the source of CFTR expression.
Accordingly, the methods of this invention are well
suited for treating CF-related pancreas and liver
disorders.
A CFTR cDNA is described in
'F. S. Collins et
al., Science, 235, pp. 1046-49 (1987) ~' -'
That
cDNA may be incorporated into any of the gene delivery
systems described above and then utilized in the
methods of this invention. For example, the
construction of certain recombinant viral vectors
containing the CFTR cDNA is described in the '274
application. Those vectors are useful in the methods
of this invention.
Most preferably, the CFTR DNA is incorporated
into a derivative of adenovirus Ad5. The construction
of this recombinant vector is described in the specific
examples, below.
According to another embodiment, the
invention provides a method of transferring genetic
material into hepatocytes. Prior to the present
invention, the only method of transfecting hepatocytes -'
in vivo involved placing the gene to be transferred in
an appropriate vehicle into the blood stream. Thus,
when the packaged genetic material passed through the
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hepatic blood vessels, it would taken up by the vessel
endothelial cells and, more efficiently, by the rapidly
dividing hepatocytes.
The problem with this technique was several
fold. First, the exposure of the genetic material to
the blood could potentially induce the formation of
antibodies to the vehicle carrying the gene of
interest. Second, the blood system is a very non-
specific conduit for transfecting hepatocytes.
Introduction of a gene into the blood system would
likely cause undesirable transfection of many other
types of cells. Also, the use of the blood system is
highly inefficient, thus requiring more genetic
material to be introduced into the patient. And
finally, the rate of excretion of excess material
delivered into the blood system may be slow, thus
causing potential deleterious effects because of
prolonged exposure of the patient to the gene and
carrier.
Applicant has discovered that the methods of
this invention will result in the transfer of genetic
material into hepatocytes, as well as the biliary
epithelial cells if the concentration of vehicle
carrying the desired genetic material introduced into
the biliary ducts is increased. In order to transduce
hepatocytes, as well as biliary epithelial cells, when
utilizing a viral carrier, the concentration of virus
should be in the range of about 101'-101° pfu/ml with
administration being between about 0.1-100 ml/kg body
weight. More preferably, the concentration of virus
should be in the range of 10"-101 pfu/ml with
administration being between about 0.5-20 ml/kg body
weight.
When the methods of this invention are used
to target genes to hepatocytes, it is preferable that
the transfer vehicle be either the recombinant
retroviruses or the recombinant adenoviruses described
-12-
in this application.
The ability to transfer genes into
hepatocytes using the methods of this invention allows ,.
for the treatment and possible cure of genetic diseases
of these cells. Such diseases include familial _-
hypercholesterolemia and other lipid disorders,
ornithine transcarbamylase deficiency, phenylketonuria
and a-1 antitrypsin deficiency.
In order that the invention described herein
may be more fully understood, the following examples
are set forth. It should be understood that these
examples are for illustrative purposes only and are not
to be construed as limiting this invention in any
manner.
EXAMPLE 1
Construction Of Recombinant Adenovirus
I. pAd.CMV-lacZ
A. Preparation of a CMV Promoter-lacZ Miniqene
Plasmid pUCl9 [C. Yanisch-Perron et al.,
Gene, 33, pp. 103-19 (1985)] was digested with SmaI and
an 8 nucleotide NotI linker was then cloned onto the
end. This destroyed the SmaI site, while creating two
SacII sites on either side of the linker. A 196 base
pair fragment containing the polyadenylation signal of
SV40 (SV 40 nucleotides 2533-2729) was then purified
from an SV40-containing vector [G. MacGregor et al.,
Somat. Cell Mol. Gen., 13, pp. 253-65 (1987)]. ~amHI
linkers were added to that fragment, which was then
cloned into the single BamHI site of the modified pUCl9
vector. The polyadenylation signal was oriented so
that transcription that began with a promoter upstream
from the l~otI site and passed through that restriction
site will encounter the SV40 late gene polyadenylation
signal. The SV40 early gene polyadenylation signal is
in the opposite orientation.
A 180 base pair XhoI-PstI fragment from
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plasmid pLl [H. okayama et al., Col. Cell Biol., 3, pp.
280-89 (1983)] containing the SV40 late viral protein
gene 16s/19s splice donor and accept signals was then
' cloned into the above vector to provide the appropriate
signals. The human cytomegalovirus immediate early
gene promoter and enhancer, obtained as a 619 base pair
~a_I fragment from pCM5029 [M. Boshart et al., Ce ,
41, pp. 521-30 (1985)], was cloned into the HincII site
of pUCl8 and subsequently recovered from that vector as
part of a BamHI/HindIII fragment. That fragment Was
then treated with T4 polymerase and blunt-end ligated
into the above-described modified pUCl9 vector.
The ~. co i l3-galactosidase gene was cut out
of pC4AUG [G. R. McGregor et .al., Somat. Cell Mol.
Genet., 13, pp. 253-65 (1987)] with EcoRI and ~baI as a
3530 base pair fragment. NotI linkers were then added
to the fragment and the resulting construct cloned into
the J~otl site of the above-described modified pUCl9
vector.
The entire minigene containing the CMV
promoter/enhancer, the lacZ gene and the SV40
polyadenylation signal was then excised from the pUCl9
vector with SphI. The fragment was treated with Klenow
fragment and ligated with Bc I linkers.
B. Preparation of pAdBglII And Ligation Of
the Minicre~e Into That Plasmid
Plasmid pEHX-L3 [E. Falck-Pedersen et al., J.
V'ro ., 63, pp. 532-42 (1989)], which contains
sequences from Ad5 spanning map units 0 to 16.1, was
digested with coRI and BalII to remove a 5.2 kilobase
,. fragment containing the adenovirus sequences from map
unit 9.2 to 16.1, as well as the plasmid backbone. The
adenovirus sequences spanning 0 to 1 map units and
containing the 5' inverted repeat, origin of
replication and encapsidation signals were amplified
from the original pEHX-L3 vector and given an dhel site
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I
-14-
at the 5' end, immediately downstream from the c~oRI
site, and a ~g_lII site at the 3' end, using PCR. The
PCR-amplified fragment was then ligated to the
roRI/$g~II fragment to produce plasmid pAdBglII.
The lacZ-containing minigene prepared as -
described in part A, above, was then cloned in direct
orientation into the pAdBgIII vector which had been
digested with III and treated with calf intestinal
phosphatase. A schematic representation of pAd.CMV
lacZ is depicted in Figure 1.
II. pAd.CB-CFTR
Plasmid pAd.CB-CFTR is derived from pAd.CMV-
lacZ. It contains the chicken !3-actin promoter, the
human CFTR cDNA and a small portion of Mo-MLV
retroviral sequences in the place of the CMV promoter
and lacZ gene.
A. Construction of pCMV-EA-CFT,~t
The vector pBA-CFTR contains an intact 5' LTR
of Mo-MLV and additional Mo-MLV viral sequences between
the 5' LTR and the internal promoter spanning
nucleotides 146 to 624. The plasmid also contains
wild-type Mo-MLV sequences from the C aI site at
nucleotide 7674, which was subsequently converted to a
BamHI site with synthetic linkers, to the end of the 3'
LTR. Sequences containing the viral enhancer elements
of the 3' LTR from the PvuII site at nucleotide 7933 to
the ~bal site at nucleotide 8111 were deleted. In
addition to the above-described sequences, the vector
also contains flanking mouse genomic DNA and pBR322
sequences spanning the HindIII site to the SRI site.
The f3-actin promoter in this vector was
derived from a C~oI-~bo.I fragment of the chicken t3-
actin gene spanning nucleotides -266 to +1 [T. A. Kost
et al., Nucl. Acids Res., 11, pp. 8287-301 (1983)].
The MboI site was subsequently converted to a BamHI
site and the modified promoter fragment cloned into the
above vector. The human CFTR coding sequences were
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derived from a 4.6 kb SacI fragment of a CFTR cDNA [J.
R. Riordan et al., Science, 245, pp. 1066-73 (1989)]
and contained, in addition to the entire CFTR coding
region, small amounts of 5' and 3' untranslated
regions. The SCI sites were converted to ~I sites
and the modified fragment was cloned into the ~amHl
site of the above vector, immediately following the l3-
actin promoter.
Enhancer sequences from the immediate early
gene of human CMV were obtained by digesting CDM1 [8.
Seed et al., roc. Natl. Acad. Sci. USA, 84, pp. 3365-
69 (1987)] with SneI and ~stl, purifying the enhancer
sequence-containing fragment and cloning into pUCl9. A
portion of the enhancer sequence was then excised from
that vector with C~h-oI and coI. After purification,
the coI site was converted to an h~I site through the
addition of synthetic linkers and the modified fragment
was cloned into the unique XhoI site located 5' to the
f3-actin promoter of the above-described vector. The
resulting vector was termed pCMV-BA-CFTR.
B. Replacement of lacZ Minigene In
p~D.~-lacZ With CFTR Miniaene
The vector pCMV-BA-CFTR was digested with
XhoI and ~heI to release a fragment containing the 13-
actin promoter, the CFTR gene and a small amount of
retrovirus-specific sequences and then blunt-ended.
Plasmid pAd.CMV-lacZ was cut with naBI and No I to
excise the CMV promoter and the lacZ structural gene.
The remaining portion of the plasmid, which retained
the CMV enhancer and the SV40 polyadenylation signal,
was blunt-ended and ligated with the blunt-ended
fragment from pCMV-BA-CFTR to form plasmid pAd.CB-CFTR.
A schematic representation of pAd.CB-CFTR is depicted
in Figure 2.
Plasmids prepared by the processes described
above are exemplified by recombinant DNA molecules
deposited in the American Type Culture Collection,
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12301 Parklawn Drive, Rockville Maryland 20852, USA on
May 10, 1993 and identified under the following
accession number: -
ATCC 75468 - pAd.CB-CFTR.
III. Generation of Rgcombinant Ad. CB-CFTR Virus
The vector pAd.CB-CFTR was linearized with
dheI and mixed with ~CbaI digested d17001 viral genome.
The d17001 virus is an Ad5/Ad2 recombinant virus that
has a deletion in the E3 sequences spanning 78.4 to --
86 map units. That virus was derived from an Ad5-Ad2-
Ad5 recombinant virus made up of the coRI fragment of
Ad5 spanning 0-76 map units, the EcoRI fragment of Ad2
spanning 76-83 and the coRl fragment of Ad5 spanning
83-100 map units. The sequences spanning map units
78.4 to 86 of this Ad5-Ad2-Ad5 recombinant virus were
then excised to form d17o01 [Claearas and Wold, V' o .,
140, pp. 23-43 (1985)).
I grew 293 cells [F. L. Graham et al., in
Methods in Molecular Biology. Vol. 7, E. J. Murray,
ed., The Humana Press, Clifton, NJ, pp. 109-28 (1991)]
in 15o mm plates containing DMEM supplemented with 10%
fetal calf serum, 100 U/ml penicillin and 100 ~tg/ml
streptomycin ("1% pen-strep") until reaching 80%
confluency. The cells were then cotransfected with the
linearized Ad.CB-CFTR and XbaI digested d17001. The
cells were allowed to grow until plaques formed.
Individual plaques were then isolated and amplified in
293 cells. I then isolated viral DNA from individual
plaques and analyzed it for the presence of human CFTR
DNA via restriction enzyme cleavage and Southern blot
analysis.
One of the CFTR-positive plaques was then
plaque purified for a second time and the virus therein -'
designated Ad.CB-CFTR. That virus was propagated in
293 cells as follows. Thirty 150 mm plates of 293
cells were grown as described above until reaching 80-
CA 02500213 1994-05-10
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90% confluency. The media was removed and the cells
were then infected with Ad.CB-CFTR (contained in l0 ml
DMEM/1% pen strep) at a m.o.i. of 10 for two hours. I
then added 20 ml of DMEM/15% fetal bovine serum/1% pen-
s strep and continued incubation. At about 36-40 hours
post-infection, I harvested the cells by centrifugation
and resuspended them in 18 ml of 10 mM Tris-HC1, pH
8.1. The cells were broken open by three rounds of
freezing/thawing. The cell debris was then pelleted by
centrifugation at 1500 x g for 20 minutes. The
supernatant was removed and the pellet was washed once
with 10 mM Tris-HC1, pH 8.1. The supernatants were
combined and were layered onto 20 ml CsCl step ,
gradients (1.20 g/ml and 1.45 g/ml in 10 mM Tris-HC1,
pH 8.1) and centrifuged for 2 hours at 100,000 x g. I
then removed the band of viral particles, diluted them
in one volume of the Tsis buffer and subjected them to
a second round of CsCl banding on 8 ml gradients.
After centrifugation for 18 hours at 100,000 x g, I
recovered the viral particles and stored them in 5
volumes of 10 mM Tris-HC1, pH 8.1, 100 mM NaCl, 0.1%
BSA, 50% glycerol. Prior to use I desalted the viral
preparation by gel filtration through Sephadex G50 in
Hams media.
The final concentration of virus was
determined by measuring absorbance at 260 nm. I
estimated the titer of the virus via a plaque assay
using 293 cells. I also checked for the presence of
replication competent virus by infecting HeLa cells at
an moi of 10, followed by passaging the cells for 30
days. The presence of replication competent virus is
confirmed by observing cytopathic effects in the
infected HeLa cells. None of the virus used in the
following procedures was replication competent.
CA 02500213 1994-05-10
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EXAMPLE
Ability of Ad.CB-CFTR To Transform CF Cells _
I initially tested the ability of Ad.CB-CFTR
to transfer the CFTR gene in the cell line CFPAC, .
derived from a pancreatic adenocarcinoma of a patient
with CF ~M. L. Drumm et al., Cell, 62, pp. 1227
(1990)]. I grew these cells at 37°C to confluency in
Iscove's modified Delbecco medium (Gibco Laboratories,
Grand Island, NY) supplemented with l0% fetal calf
serum and 1% pen-strep in 10 cm2 plates. I then
infected the cells with a Ad.CB-CFTR at an m.o.i. of 1.
After 48 hours post-infection the cells were analyzed
for gene transfer and expression of CFTR. Analysis was
performed on cellular DNA and RNA, as well as using
immunocytochemistry to analyze whole cells.
Radiolabelled hybridization probes were synthesized
from a PCR template derived from the rat CFTR cDNA
(nucleotides 1770-2475) described in M. A. Fielder et
al, Am. J. Physiol., 262, p. L779 (1992),
utilizing the Promega in vitro transcription
system (Promega Corporation, Pittsburgh, PA) and
following the manufacturer's directions. The probes
were used in Southern and Northern blot analyses, as
well as in in situ hybridization studies.
Total cellular DNA from both mock infected
and Ad.CB-CFTR infected cells (l0 fig) was isolated and
digested with ~I. Southern blots of the DNA derived
from the infected cells demonstrated high levels of
gene transfer (Figure 3). Total cellular RNA from both
mock infected and Ad.CB-CFTR infected cells was _,
isolated, electrophoresed in formaldehyde/agarose gels
and transferred to nylon membrane. Northern blots .,
demonstrated an abundant level of CFTR transcripts
(Figure 4).
Immunocytochemistry was also performed on the
cells to detect CFTR protein. The cells were fixed in
CA 02500213 1994-05-10
-19-
methanol at -20C for 10 minutes and then incubated with
20% normal goat serum in phosphate buffered saline
("GS/PBS") for 30 minutes. The cells were then
incubated with 5 ~,g/ml of a rabbit polyclonal antibody
raised against a C-terminal peptide (amino acids 1468-
1480) that is conserved in human and rat CFTR [J. A.
Cohn et al., B~ochem. Biophys. Res. CQmmuns, 181, p. 36
(1991); C. R. Marino et al., J. Clin. Invest., 88, p.
712 (1991); J. A. Cohn et al., PrQc. Natl. Acad. Sci.
US , 89, p. 2340 (1992)] in 2% GS/PBS for 5o minutes.
Controls included incubation with a non-reactive
antibody and pre-incubation of the anti-CFTR peptide
antibody with 0.5 mg/ml of CFTR peptide in 2% GS/PBS ,
overnight at 4C prior to incubation with cells.
Following incubation with antibody, the cells were
washed three times with 2% GS/PBS for 5 minutes. The
antibody was visualized. by incubating the cells with a
goat anti-rabbit IgG coupled to FITC. The results of
this experiment demonstrated that almost all of the
cells exposed to the virus expressed detectable levels
of CFTR (Figure 5).
The cells were also assayed for the ability
to perform cAMP regulated anion conductance -- a
characteristic of expression of functional CFTR
protein. Specifically, I grew the cells on collagen-
- coated glass coverslips to confluency under the
conditions described above. I then removed the media
and replaced it with a hypotonic 1:1 dilution of NaI
buffer (130 mM NaI, 4 mM KN03, 1 mM Ca(N03)2, 1 mM
Mg (N03) 2, 1 mM Na2HP04, 10 mM glucose, 20 mM HEPES, pH
7.4) in water. I then added 10 mM (final
.. concentration) of the halide-sensitive fluorophore, 6-
methoxy-N-(3-sulfopropyl) quinolinium ("SPQ") and
incubated for 12 minutes at 37C. I removed the SPQ-
containing buffer and replaced it with undiluted,
isosmotic NaI buffer and incubated the cells for an
additional 5 minutes. The coverslips were then
CA 02500213 1994-05-10
-20-
transferred to the microscope stage where they were
imaged using a 4oX oil emersion lens (Nikon CF fluor
lens) under light~passed through an excitation filter ,-
of 370 nm. Emitted fluorescence from the cells was
collected by a high resolution image intensifier (Video
Scope, Inc, Washington, D.C.) coupled to a video
camera. The signal output from the camera was
connected to a digital imaging processing board
controlled by IMAGE 1/FL software (Universal Imaging,
Media, PA).
Almost all of the cells exposed to the virus
regained the ability to perform cAMP-regulated anion
conductance. This experiment demonstrated that the
Ad.CB-CFTR virus was capable of carrying out gene '
transfer in cells and cure defects in the CFTR gene.
EXAMPLE
In Vivo Transfection Of Rat Bili~ry EEithelial Cells
I utilized the Ad.CMV-lacZ virus, described
in Example 1, to develop techniques for the in vivo
targeting of biliary epithelial cells in rats.
Male Sprague Dawley rats (approx. 200 gms)
were anesthetized with isoflurane and their viscera
exposed through a midline incision. I then identified
the common bile duct and cannulated it with a 27 gauge
needle. Various concentrations of virus (1x10'1 - 2x10'2
pfu/ml) were suspended in 0.3 ml of phosphate buffered
saline and one 0.3 ml aliquot was slowly infused
retrograde into each rat. Upon completion of the
infusion, I removed the needle and gently applied
pressure over the puncture site of the bile duct. The .,
skin and fascia were then closed in one layer with
interrupted sutures and the animal was allowed to
recover.
As a control, I used the Ad. CB-CFTR virus
(1x10" pfu/ml), described in Example 2 for retrograde
infusion.
CA 02500213 1994-05-10
s
-21-
After three days, the animals were
euthanized. The liver tissue was then evaluated for
lacZ expression using Xgal immunochemistry. Fresh
frozen sections (6 Vim) were mounted, post fixed in 0.5%
glutaraldehyde/PBS for l0 minutes, washed twice with 1
mM MgClZ/PBS and incubated in Xgal solution (1.6 mg/ml
K3Fe (CN) a, 2 .1 mg/ml K4Fe (CN) b 3H20, 40 mg/ml Xgal) for 4
hours. Animals infused with the maximum amount of
virus (2x102 pfu/ml) demonstrated lacZ expression in
all of the biliary epithelial cells, as well as over
80% of the hepatocytes. At lower doses of the virus
(lxl0'~ pfu/ml), gene transfer was more selective in
that less than 1% of the hepatocytes expressed lacZ, ,
while almost all intrahepatic~bile duct epithelial
cells continued to express lacZ (Figure 6, panels B and
C). Animals infused with Ad.CB-CFTR did not
demonstrate lacZ expression (Figure 6, parel A).
In order to evaluate the stability of the
expression of this transferred gene, rats receiving the
more selective dose of virus were euthanized at 7 and
21 days post-infection. By seven days, expression in
hepatocytes and epithelia of the large bile ducts was
markedly diminished (Figure 6, panel D). However, lacZ
expression in the epithelia of the small biliary ducts
remained consistent throughout the 21 days (Figure 6,
panel E) .
The same types of experiments were repeated
assaying for CFTR RNA using rat or human CFTR-specific
probes. I used 0.3 ml of 1x10" pfu/ml of either Ad.CB-
CFTR or Ad.CMV-lacZ virus to infect rats. Serial
sections of liver taken from infected rats was analyzed
for the presence of CFTR RNA using in situ
hybridization with probes specific for either rat or
human CFTR. The biliary epithelial cells of Ad.CMV-
lacZ infected rats hybridized to the rat CFTR probe
(Figure 7, panel A), but not to the human probe (Figure
7, panel B). This demonstrated the specificity of the
CA 02500213 1994-05-10
-22-
human probe. Animals infected with the Ad. CB-CFTR
virus demonstrated a diffuse distribution of human CFTR
RNA throughout the biliary epithelial cells of large
and small intrahepatic bile ducts (Figure 7, panel C).
That distribution was similar to the distribution of
the endogenous rat CFTR RNA (Figure 7, panel D). In
addition, the human CFTR transcript was detected in a
small number of hepatocytes.
The rat liver sections were also analyzed by
double immunodiffusion using antibodies specific for
CFTR and for cytokeratin-18, a marker expressed at high
levels in biliary epithelial cells. Animals treated
with Ad. CB-CFTR demonstrated binding of CFTR antibody
to the apical surface of most biliary epithelial cells
(Figure 8, panel A). This binding was in far excess of
the binding of the antibody to endogenous CFTR protein
in Ad.CMV-lac2 infected.animals (Figure E, panel C).
The CFTR specific antibody binding detected in Ad.CB-
CFTR infected animals localized to the same cells as
antibodies to cytokeratin-18 (also demonstrated for
Ad.CMV-lacZ infected animals), confirming that the
recombinant CFTR is expressed in the proper cell type
(Figure 8, panels B and D).
EXAMPLE 4
CFTR Gene Transfer Into Biliary And
Pancreatic Ductal Epithelia Of Human Patients
Ad. CB-CFTR is used to treat the hepatobiliary
and pancreatic aspects of CF. A patient suffering from
CF is subjected to endoscopy to visualize the duodenum
and locate the common bile duct. Once located, the
common bile duct is cannulated. A suitable
concentration of virus (approx. 1x10" pfu/ml) in 50-150
ml PBS is inserted into the common bile duct via
endoscopic retrograde cholangiography. Following the
procedure, the patient will begin to express CFTR in
the biliary epithelial cells.
CA 02500213 1994-05-10
-23-
For treatment of the pancreatic aspects of
CF, a similar protocol is followed. A ligature is
placed between the liver and pancreatic duct. A needle
is then inserted into the bowel to infuse the virus
into the pancreatic ducts.
Similar recombinant adenoviruses carrying
other genes or cDNA copies thereof are utilized in the
same procedure to cure other genetic defects of these
epithelial cells. Genetic defects of hepatocytes,
pancreatic acinar cells and pancreatic islet cells can
also be cured using such recombinant viruses if the
viruses are administered into the biliary and
pancreatic ducts at a higher concentration. ,
While I have hereinbefore presented a number
of embodiments of this invention, it is apparent that
my basic construction can be altered to provide other
embodiments which utilize the processes of this
invention. Therefore, it will be appreciated that the
scope of this invention is to be defined by the claims
appended hereto rather than the specific embodiments
which have been presented hereinbefore by way of
example.
CA 02500213 1994-05-10
23/1
Applinars~sgenusfile pCT IlntemauonalapphatronNo.
rcierenx number UM-.~.
INDICATIONS RELATING TO A DEPOSITED MICROORGANISM
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A. 'fhe iedrcauons mauc bciow
relate to the mtaoorpntsm referred
w m the desaiptbrt
~n page 15 . line 3 5-,paae
16 . nee 4 _
II. IDENTIFICATION OF Ut;l'USff
Plasmid DNA, Funher deposes
are tdentifed on sit additions)
sheet a
Name of dep~itary msutuuon pAd
. CB-CFTR
American Type Culture Collection
Address of deposnary mstnuuon
naclwlint polio! code end earwuy~
12301 Parklawn Drive
Rockville, Maryland 20852
United States of America
Uate of deposit Aaoess~on Number
May 1993 (10.05.93) I 75468
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or is deemed to be ithdratvn,
as provided in Rule 28(3) of
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Implementing Regulations under
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sam le to an er, ert nominated
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rcierenoe number UM-2 PCT
INDICATIONS RELATING TO A DEPOSITED MICROORGANISM
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rcute to the mHxa~ptusm reiermo
to tn the descnptbtt
on page 15 , line 35-page 16,
l;ne 4
a. IDENTIFICATION nF DEl'USTT
P la amid DNA r Fuller depaata
ate identified on an additional
sbeer a
Name of depostury msutuum pAd
. CB-CFTR
American Type Culture Collection
Address of dcposuarv msmut~on
lurlw4et pastel rodseeJ corerrr)
12301 Parklawn Drive
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United States of America
Uate of dcpasu Acoess~on Number
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