Angiogenesis: Synthetic Emphasis on FumagillinKeith KorthalsLiterature PresentationJuly 1, 2004Rodeschini, V.; Boiteau, J.-G.; Van de Weghe, P.; Tarnus, C.; Eustache, J. Journal of OrganicChemistry 2004, 69 (2), 357-373.Picoul, W.; Bedel, O.; Haudrechy, A.; Langlois, Y. Pure Appl Chem 2003, 75 (2-3), 235-249.Vosburg, D. A.; Weiler, S.; Sorensen, E. J. Angewandte Chemie, International Edition 1999,38 (7), 971-974.Ingber, D.; Fujita, T.; Kishimoto, S.; Sudo, K.; Kanamaru, T.; Brem, H.; Folkman, J. Nature1990, 348 (6301), 555-7.Corey, E. J.; Snider, B. B. Journal of the American Chemical Society 1972, 94 (7), 2549-&.Overview• Story of Angiogenesis• First Total Synthesis Fumagillin 1972• Recent Total Synthesis 1999• Synthesis of Analogs 2004• IC50 of the AnalogsWhat is Angiogenesis?• Simply, this is the process of new blood vesselgrowth.• It is important in fetal development, cancer, diabeticretinopathy.Current State of Drug Developement• The first angiogenesis-stimulating medicine is aprescription gel called Regranex (Ortho-McNeilPharmaceuticals) that became FDA-approved toheal diabetic foot ulcers in December 1997.• Currently no FDA approved angiogenesis inhibitor• Many current clinical trials (~60).How was the concept of AngiogenesisInhibition Discovered?Pioneer Work: Dr. Judah Folkmanwho when removing canceroustissue made a simple observationthat cancer tumors were “hot, bloody,and full of vessels.”Attached a living tumor to the cornea Inrabbits. Within two days blood vesselswere observed growing into the cornea tothe tumor. When the vessels reached thetumor, it grew 16,000 times its originalsize. When the tumor was removed, theblood vessels went away.But what is the mechanism?• Put your tumor in a blender.• Start your column.• Lose some hair, turn grey.• Ten years later you have a compound. Luckily, itsticks to heparin (anticoagant).• Absorbed onto a matrix (slow release pellet) whenplaced on rabbit eyes, blood vessels grow in.• When removed, blood vessels die off.• VEGF (Vascular endothelial growth factor-A , -C)How to find an Angiogenesis Inhibitor?• This was Bob Langer’s job.• Step one: Kill a few cows (1970’s).• Take over some space at Harvard.• Hire an army of postdocs and scape out some bonecartilage.• Get your column and get a chair because you aregoing to be there a while.• As luck would have it, a fungus starting growing in acell culture of capillary cells. The cells witheredaway from this fungus.• Breaking all the rules, Dr. Don Ingber cultured them.• This was Aspergillus fumigatus which secretedfumagillin. Analog is in clinical trials (TNP-470).Ingber, D.; Fujita, T.; Kishimoto, S.; Sudo, K.; Kanamaru, T.; Brem, H.; Folkman, J.Nature 1990, 348 (6301), 555-7.McCowen, M. C.; Callender, M.; Lawilis, J.F. Science, 1951, 113, 202.Other Compounds• Endostatin - cleaved product of the carboxyl-terminaldomain of collagen (phase I)• Angiostatin - large protein fragment (phase I)• 2-Methoxyestradiol (phase II completed)• Can be purchased from AldrichCH3OHMeOHODiabetic Retinopathy• Leading cause of blindness• Diabetes damages the blood vessels in the retina of the eye• Mild Nonproliferative Retinopathy. At this earliest stage,small areas of balloon-like swelling in the retina's tiny bloodvessels occur.• Moderate Nonproliferative Retinopathy. As the diseaseprogresses, some blood vessels that nourish the retina areblocked.• Severe Nonproliferative Retinopathy. Many more bloodvessels are blocked, depriving several areas of the retina withtheir blood supply. These areas of the retina send signals to thebody to grow new blood vessels for nourishment.Diabetic Retinopathy• Proliferative Retinopathy.– At this advanced stage, the signals sent by the retina fornourishment trigger the growth of new blood vessels. Thiscondition is called proliferative retinopathy.– These new blood vessels are abnormal and fragile.– They grow along the retina and along the surface of theclear, vitreous gel that fills the inside of the eye.– These blood vessels do not cause symptoms or vision loss.– However, they have fragile walls. If they leak blood, visionloss and blindness can result.Vision EffectsTreatment Methods• Laser surgery is currently the only treatmentFumagillin and Analogs• Fumagillin first shown to inhibit angiogenesis in ~1990.• It was known to have anti-cancer properties since 1958.• First discovered in 1951.• Used as an antibiotic.• Analog TNP-470 is currently in clinical trials for cancer treatmentas an angiogenesis inhibitor.• The binding of this compound to an enzyme MetAP-2(aminopeptidase-2) has an X-ray crystal structure.Ingber, D.; Fujita, T.; Kishimoto, S.; Sudo, K.; Kanamaru, T.; Brem, H.; Folkman, J. Nature 1990,348 (6301), 555-7.Fumagillin and AnalogsMetAP-2 removes NH2-terminal methionines fromproteins. This promotes theproliferation of endothelialcells (blood vessel cells) Liu, S. P.; Widom, J.; Kemp, C. W.; Crews, C. M.; Clardy, J. Science 1998, 282 (5392), 1324-1327.Human MetAP-2First SynthesisCorey, E. J.; Snider, B. B. Journal of the American Chemical Society 1972, 94 (7), 2549-&.COOCH3OHCCOOCH3COOCH3SeO241 % yield(Ph)3P84 % yield1:1 mixtureCOOCH3BrCHO80 % yieldCHOBrNaBH4COOCH3Brreflux, K2CO3wet, THFTMSCl, NEt3COOCH3BrHOTMSOH98 % yield90 % yieldFirst SynthesisCOOCH3BrTMSO1 eq. mCPBACH2Cl2, 0 oCCOOCH3BrTMSOCOOCH3BrTMSOOO+9:1 mixture, 80 %1) TBAF, THF2) NaOMeCOOCH3OO+COOCH3OOHH9:1 mixtureHHHHRRHCOOCH3R's are the Br and CH2OTMSHHCorey, E. J.; Snider, B. B. Journal of the American Chemical Society 1972, 94 (7), 2549-&.First SynthesisCOOCH3OO+COOCH3OOH9:1 mixtureHOsO4, pyridineCOOCH3OO+COOCH3OOH9:1 mixture, 81 % yieldHOHHOOHHOseperate here!COOCH3OOHOHHONa t-amylateMeICOOCH3OOHOMeHO47 % yieldMeLi excess, -78 oCOOHOMeHOOH75 % yieldOOHOMeOHOO95 % yield1) MsCl, NEt3, THF2) tetrabutylammonium bromideCorey, E. J.; Snider, B. B. Journal of the American Chemical Society 1972, 94 (7), 2549-&.First SynthesisOOHOMeOOOOHOMeOO+3:1 ratioMeOH, K2CO3OOHOMeHOOOHOMeHO+3:1 ratio seperated by HPLCyield not reportedOOHOMeHOOOClCl4OO HOMeOOOOH4columnyield not reported(±)-FumagillinCorey, E. J.; Snider, B. B. Journal of the American Chemical Society 1972, 94 (7), 2549-&.Fumagillin SynthesisTaber, D. F.; Christos, T. E.; Rheingold, A. L.; Guzei, I. A. Journal of the American ChemicalSociety 1999, 121 (23), 5589-5590.96:4 separate Lemenez, P.; Fargeas, V.; Poisson, J.;