1. Daniel J. Albershardt Senior, Dept. of Biochemistry/Biophysics Transplacental DNA Adduct Formation by Dibenzo[a,l]pyrene in Mice Dr. William M. Baird Laboratory

2. Overview Introduction Methods Summary

3. Polycyclic Aromatic Hydrocarbons (PAH) Found in complex environmental pollutants Formed by incomplete combustion of organic compounds Human exposure linked to cancer incidence

4. Dibenzo[a,l]pyrene Dibenzo[a,l]pyrene (DBP) Related compounds have been shown to be transplacental Anderson, LM, Ruskie, S, Carter, J, Pittinger, S, Kovatch, RM, Riggs, CW. Pharmacogenetics (1995) 6:364-72

5. PAH Metabolism Many sites can be epoxidated. Epoxides are unstable. Epoxide hydrolase may hydrolyze the epoxide to a diol. Subsequent epoxide is a more stable, reactive electrophile.

6. Chen J, et. al. "MMDB: Entrez's 3D-structure database", Nucleic Acids Res. 2003 Jan; 31(1): 474-7.

7. (-)-anti-DB[a,l]PDE [nM] Types of Sequence AlterationDMSO12510 Base Substitutions8(73%)11(79%)16(67%)25(74%)38(81%) Exon Deletions3(27%)3(21%)3(12%)3(9%)1(2%) ±1 Frameshifts004(17%)2(6%)4(9%) Tandem Mutations001(3%)2(6%)1(2%) Small Insertions0001(3%)1(2%) Total11(100%)14(100%)24(100%)33(100%)45(100%) No. of Mutant Clones Analyzed714 15 B. Mahadevan, W.-M. Dashwood, A. Luch, A. Pecaj, J. Doehmer, A. Seidel, C. Pereira, and W. M. Baird. Environ. Mol. Mut. 41:131-9 (2003) Mutations by Dibenzo[a,l]pyrene

8. Objectives Determine transplacental DNA adduct formation by DBP in mice Relevance to human health

9. 17 th Day Gestation 15mg DBP/kg body mass Sacrifice via CO 2 (maternal) or decapitation (fetal) Lung and liver removed DNA isolated and 33 P postlabeled HPLC Analysis Methods

11. STANDARD HPLC Profiles Controls: DBP

12. 6 Hours 2 Days4 Days6 Days 1 Day Maternal Lung Tissue HPLC Profiles

13. Total DNA Adducts in Maternal Lung Tissues Total DNA Adducts (pmol/mg)

14. Fetal Lung Tissue HPLC Profiles 2 Day Exposure

15. Total DNA Adducts After 2 Days Exposure Maternal Total DNA Adducts (pmol/mg) P1P2P3P4P5P6P7

16. Fetal Liver Tissues No DNA adducts detected using our method

17. Summary DNA adducts found in maternal lung tissues at all exposure times 2 days exposure to DBP formed DNA adducts in fetal lung tissue No DNA adducts detected in fetal liver tissue after 2 days exposure

18. Future Research DNA adduct determination of: Maternal Liver Fetal Lung and Liver at Different Exposure Times

19. Acknowledgements Dr. William M. Baird Dr. Kevin Ahern Dr. Brinda Mahadevan Tamara Musafia Dr. David Williams Yu Zhen Mandy Louderback Howard Hughes Medical Institute LARC