inhibition of cyp1b1 in mcf-7 and v79 h1b1 cells in culture
DESCRIPTION
Inhibition of CYP1B1 in MCF-7 and V79 H1B1 Cells in Culture. Tuan M. Nguyen Major: General Science/Pre-Optometry Mentors: Dr. William M. Baird & Dr. Brinda Mahadevan. Overview. Introduction Methods Results Summary. Introduction. - PowerPoint PPT PresentationTRANSCRIPT
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Tuan M. NguyenMajor: General Science/Pre-Optometry
Mentors: Dr. William M. Baird & Dr. Brinda Mahadevan
Inhibition of CYP1B1 in MCF-7 and V79 H1B1 Cells in Culture.
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Overview• Introduction
• Methods
• Results
• Summary
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Introduction• Polycyclic aromatic hydrocarbons (PAH)
are environmental carcinogens
• Cytochrome P450 (CYP) enzymes such as CYP1B1 have been identified to be involved in the activation of dibenzo[a,l]pyrene (DBP)
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Introduction• DBP is one of PAH forms
• DBP commonly found in cigarette smoke, diesel exhaust, urban dust and other environmental carcinogens.
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DNA adduct formation on
exposure to DBPO
7
812910
13
11
fjord region 1
4
614
OHHO
OHHO
N
N
Ν
Ν
O
2
5
3
+
(–)-anti-DB[a,l]P-11,12-dihydrodiol 13,14-epoxide
O
(+)-syn-DB[a,l]P-11,12-dihydrodiol 13,14-epoxide
dibenzo[a,l]pyrene(DB[a,l]P)
OHHO
HO
OH
OH
ΝH
Ν
Ν
Ν
Ν
O
ΝHHO
HO
OH
OH
OH
(+)-syn-DB[a,l]P-11,12-dihydrodiol 13,14-epoxide-
dA adduct
(–)-anti-DB[a,l]P-11,12-dihydrodiol 13,14-epoxide-
dA adduct
DBP diol-epoxides
DBPDE
DNA adducts
CYP 1A1
CYP 1B1
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Objective
• To investigate the importance of CYP1B1 as key enzyme in metabolizing DBP to its metabolites.
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Aspects of Study• DNA adducts
• CYP1B1 enzyme activity
• CYP1B1 gene expression
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Experimental Design
DNA Adducts
MCF-7 Cells• TMS (- control)• TMS+DBP• DBP• DBPDE (+ control)
V79 H1B1 Cells• TMS (- control)• TMS+DBP• DBP• DMSO (solvent ctrl)
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MethodsAdd fresh media to cells 24 hrs prior to treatment
20 ml media
TMS (-)TMS+DBPDBPDMSO (solvent ctrl)
DNA RNA & Microsome isolation isolation
Postlabeling & HPLC
20 ml media
P450 Glo Assay
24hr
RT-PCR
TMS (-)TMS+DBPDBPDBPDE (+)
MCF-7 V79 H1B1
Harvest
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Measurement of DNA Adducts
•Postlabeling
•Sep-pak
•HPLC
Dinucleotideadducts
Adducteddinucleotide monophosphates
Nucleoside 5’ phosphate
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HPLC Profiles
Retention Time [min]
0
1000
2000
3000
4000
5000
6000
0 20 40 60 80 100 120
(+)-anti-B[a]PDE-dG
0
2000
4000
6000
8000
10000
12000
0 20 40 60 80 100 120
(+)-anti-DB[a,l]PDE-dA
Rad
ioac
tivity
dGdA
dG
dA•DBPDE + control
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P450 Glo Assay
Luciferin CEE
(P450 Glo substrate)
CYP1B1luciferin lightfirefly luciferase
Cytochrome P450 Glo Assay enable the measurement of the activity of CYP1B1.
Luminescence reading
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P450-Glo Assay
P450-Glo Assay: S9 Microsomes
0100002000030000400005000060000700008000090000
1mg/ml 10mg/ml 20mg/ml 30mg/ml 41.6mg/ml
Concentration
Luminescence (RLU)
Room Temp37°C
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How does RNAi work?
•Antler, C. ‘Antisense RNA’, http://www.bioteach.ubc.ca/MolecularBiology/AntisenseRNA/.
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RNAi
siRNA NC V79 H1B1 Ctrl
V79 H1B1 + RNAi
V79 H1B1 + RNAi
MCF-7 Ctrl
MCF-7 + RNAi
Plate Cells
Transfect
Isolate RNA
Reverse Transcription Reaction
Polymerase Chain Reaction
Electrophoresis
Count Cells
NC
Untreated Ctrl
RNAi
RNAi
Untreated Ctrl
RNAi
- V79 H1B1 cells - MCF-7 cells
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Isolated RNA
100 bp Ld V79H NC V79H1B1+RNAi MCF-7 CtrlV79H1B1 Untreated
MCF-7+V79H1B1 100 bp Ld
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Total RNA
Random primersSuperscript RTRNase inhibitorRP
RPFirst strand cDNA
Amplify cDNASPP
SPP
PCR
Amplified product
RT-PCR and amplification of CYP1B1 cDNA
RT-PCR
RP – Random Primer SPP – Specific Pair Primer for CYP1B1(18-25 nt)
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Amplified CYP1B1 Gene
Ld siRNA NC V79H1B1+RNAi MCF-7 CtrlV79H1B1 Ctrl MCF-7+RNAi
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Summary
• Familiarized with postlabeling technique
• P450-Glo Assay
• RNAi
• Amplified CYP1B1 gene.
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Future Work
DNA Adducts Activity of CYP1B1 enzyme
Expression of CYP1B1 gene
DBP alone + + +TMS alone - - N/ATMS+DBP - - N/ARNAi alone - - -RNAi+DBP - - -
Predictions
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Acknowledgements
• William M. Baird• Brinda Mahadevan
• Kevin Ahern• Jennifer Atkin
• Howard Hughes Medical Institute