The Chemisty and Biology of Discodermolide - stuba.skszolcsanyi/education/files/The Nobel... ·...
Transcript of The Chemisty and Biology of Discodermolide - stuba.skszolcsanyi/education/files/The Nobel... ·...
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The Chemistry and Biology of Discodermolide
OO
OH
HO
OH
OH O
NH2
O
Yueheng JiangNovember 20, 2003
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OO
OH
HO
OH
OH O
NH2
OOutline
Discovery and Biological Activity
Total Syntheses
Structure-Activity Relationships (SAR)
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DiscoveryIsolated by Gunasekera and co-workers in 1990 from the Caribbean deep-sea sponge (Discodermiadissoluta).0.002% w/w isolation yield (7 mg/434 g of sponge).Found initially to have immunosuppressive and antifungal activities.Further revealed to be a potent microtubule stabilizer.
Gunasekera, S. P.; Gunasekera, M.; Longley, R. E.; Schulte, G. K. J. Org. Chem. 1991, 56, 1346.Longley, R. E.; Caddigan, D.; Harmody, D.; Gunasekera, M.; Gunasekera, S. P.; Transplantation 1991, 52, 650.ter Haar, E.; Kowalski, R. J.; Hamel, E.; Lin, C. M.; Longley, R. E.; Gunasekera, S. P.; Rosenkranz, H. S.; Day, B. W. Biochemistry 1996, 35, 243.
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Microtubule-stabilizing agents
O
NH2
O OH OH
HO
O
HO
O
AcO
O
O OH
HOO
O
PhOH
NH
O
R
H
H
O
OH
AcOH
BzO
O
OOHO
HO
O
N
S
RH
H
O
OMeO
O
OAc
OH
OHCO2Me O
OH O O
OOH
O
discodermolideR = Ph Taxol (BMS)R = OtBu Taxotere (Aventis)
R = H epothilone AR = Me epothilone B sarcodictyin Aeleutherobin laulimalide
ON
NMe
OON
NMe
O
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Cytotoxicity
Cytotoxic over a variety of cell lines (IC50 3-80 nM)More potent than TaxolCompetitively inhibits the binding of Taxol to tubulinActive against multi-drug resistant (MDR) and Taxol-resistant (Pgp mediated MDR) cell lines
ter Haar, E.; Kowalski, R. J.; Hamel, E.; Lin, C. M.; Longley, R. E.; Gunasekera, S. P.; Rosenkranz, H. S.; Day, B. W. Biochemistry 1996, 35, 243.Kowalski, R. J.; Giannakakou, P.; Gunasekera, S. P.; Longley, R. E.; Day, B. W.; Hamel, E.; Mol. Pharmacol. 1997, 52, 613.
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Mechanism of actionPromote tubulin polymerization in vitroStabilize microtubules against depolymerizationInterfere with Taxol-binding to microtubulesInduce microtubule bundles in cells
Consequences:
Interfere with proper formation of mitotic spindle
Cause arrest of cell cycle
Cell death by apoptosis
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Dynamic Equilibria of Tubulin-Microtubules
Taxol or Discodermolide
Taxol or
Discodermolide
Taxol or Discodermolide
Heterodimer Formation Initiation Polymerzation/Elongation
α-tubulin~50 kD
β-tubulin~50 kD
KD = 10-5
(α.β)
Nucleationcenter
StabilizedNucleation
centers
5 nm
(+) End (more grown)
(-) End (less grown)
Microtubule
Stabilizedmicrotubules
Map's
Mg2+ ; G
TP
Ca2+ ; 0
o C
Nicolaou, K. C.; Roshangar, F.; Vourlounis, D. Angew. Chem. Int. Ed., 1998, 37, 2014.
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Microtubule Bundling
Influence of discodermolide on a transformed mouse fibroblast.
Discodermolide induces microtubule bundling (tubulinappears green), which is clearly seen in the pseudopodia and near the nucleus (appears blue). As a result of this microtubule bundling, the cell is undergoing apoptosis and fragmentation of the nucleus can be seen.
Sasse, F. Current Biology, 2000, 10, R469.
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Unique Activities
Discodermolide could not substitute for Taxol in a Taxol-resistant cell line (A549-T12) that requires low concentrations of Taxol for normal growth.
Exhibits synergistic effects with Taxol in several cultured cell lines (not observed with Taxol/epothilones or Taxol/eleutherobin).
Martello, L. A.; McDaid, H. M.; Regl, D. L.; Yang, C. H.; Ment, D. T.; Pettus, R. R.; Kaufman, M. D.; Arimoto, H.; Danishefsky, S. J.; Smith, A. B. III; Horwitz, S. B. Clin. Cancer Res. 2000, 6, 1978.Giannakakou, P.; Fojo, T. Clin. Cancer Res. 2000, 6, 1613.
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Potential Candidate for Cancer Chemotherapy
Novel structureGreater or comparable efficacy to TaxolPoor substrate for P-glycoprotein (Pgp).Synergistic effect in combination with TaxolGreater water solubility (100-fold > Taxol)
Entered Phase I clinical trials in 2002 as a chemotherapeutic agent for use against solid tumors.
Myles, D. C. Annual Reports in Med. Chem., 2002, 37, 125.
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Taxol (semi-synthesis)Epothilone (fermentation)Discodermolide ( ???)
Total Synthesis of Discodermolide !(-)-Discodermolide (+)-Discodermolide
S. L. Schreiber (1993) S. L. Schreiber (1996)A. B. Smith (1995) J. A. Marshall (1998)D. C. Myles (1997) A. B. Smith (1999, 2003)
I. Paterson (2000, 2002) Novartis (2003)D. C. Myles (2003)
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Selected Total Synthesis of (+)-Discodermolide
Schreiber 1st total synthesis of (+/-)-discodermolideestablished absolute configuration
SmithDelivered ~1 g of (+)-discodermolide (2nd generation)
PatersonNovel approaches
NovartisMeet supply needs for clinical studies by total synthesis
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Structure and conformation of (+) discodermolide
OO
OH
HO
OH
OH O
NH2
O1 13
57
17 19
21
24
X-ray structure of discodermolide;hydrogen atoms omitted for clarity
Paterson, I.; Florence, G. J. Eur. J. Org. Chem., 2003, 2193.
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General Features
O
OH
OH O
NH2
OO
OH
HO
1
724
13* * *
* * ** **
OH* * *
repeating anti, syn-stereotriaddivided into three fragmentsof roughly equal complexity
HOCO2Me
Roche ester
17
Introduction of two Z-alkenes and terminal Z-diene
Fragment Coupling
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Strategy by Scheiber
O
OH
OH O
NH2
OO
OH
HO
O
OTBS
H
O
PhS
OTBS
I
OPiv
O OPMB
TBSO OH
TBSO OH TBSO OH
OHCO2Me
1 5 13
24
Nozaki-Kishi coupling enolate alkylation
71
815
16
24
Still-GennariHWE olefination
Negishi coupling
+ +
Roush crotylation Roush crotylation
Roche ester
(+)-discodermolide 1
AB C
23 2
158
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Strategy by Smith2nd Generation
O
OTBS
OTBS
O
OTBS TBSO
I
O
OH
OH O
NH2
OO
OH
HO
H
O
PMBOI
O O
PMP
OH
NO
PMBO
O
1
9
13
1924
Wittig olefination Negishi coupling
14 15
Yamamotoolefination
19
9
81
Zhao-Wittigolefination
Evans aldolreaction
OHCO2Me
Roche ester
A BC
Evans aldol
+
(+)-discodermolide 1
Common Precursor 2
15
+
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Strategy by Paterson 1st generation
O
OH
OH O
NH2
OO
OH
HO
1
724
13
boron aldol
TBSOO O
HMeO2CTBSO O
O OOBz
PMBO
OArO
PMBOO
BnO
HOCO2Me
+ +
boron aldol
6
lithium aldol
16
9 1617
24
boron aldol
Claisen [3,3]
Nozaki-Hiyama/Peterson elimination
PMB boron aldolA B
C
(+)-discodermolide 1
Roche ester
2 3 4
9
EtO2C OH
ethyl-(S)-lactate
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Synthesis of Stereotriadby Schreiber
B O
O CO2iPr
CO2iPr
B O
O CO2iPr
CO2iPr
TBSO OH TBSO OH
(R,R)-(E)-crotylboronate (S,S)-(Z)-crotylboronateTBSO O
H
2 3
Roche-ester
Roush crotylation
Subunit A & C Subunit B
Hung, D. T.; Nerenberg, J. B.; Schreiber, S. L. J. Am. Chem. Soc. 1996, 118, 11054. Roush, W. R.; Palkowitz, A. D.; Ando, K. J. Am. Chem. Soc. 1990, 112, 6348.
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Synthesis of stereotriadby Smith
CO2MeHO
PMBO CCl3, PPTS
NH
1
2 LAH3 Swern Oxidation
PMBO H
O
N O
Ph
OOn-Bu2BOTf, Et3N
52-55%, 4 steps
N O
O OOH
PMBO
Ph
AlMe3, THF, 98%
N
OOH
PMBOOMeNH(OMe).HCl
Common Precursor 2
3
4
Smith, A. B. III; Beauchamp, T. J.; LaMarche, M. J.; Kaufman, M. D.; Qiu, Y.; Arimoto, H.; Jones, D. R.; Kobayashi,K. J. Am. Chem. Soc. 2000, 122, 8654.Smith, A. B. III; Kaufman, M. D.; Beauchamp, T. J.; LaMarche, M. J.; Arimoto, H. Org. Lett. 1999, 1, 1823.Iversen, T.; Bundle, D. R. J. Chem. Soc., Chem. Commun. 1981, 1240.
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Synthesis of stereotriadby Paterson
O
BnO
cHex2BClEt3N, Et2O
H
O O
BnO
OB
LL
+ -
LiBH4
OH
BnO
OH2
6 stepsSubunit A
O
PMBO
cHex2BCl, Et3Nmethacrolein
95%, >30:1 dr OPMBO OH
Me4NBH(OAc)3
94%, > 30:1 dr OHPMBO OH3 7 8
6 stepsSubunit B
OOBz
cHex2BCl, Me2NEt> 97% ds
TBSO
OPMBO
TBSOCHO
4 10
OBz6 steps
Subunit C
5 6
86%> 30:1 dr
Paterson, I.; Florence, G. J.; Gerlach, K.; Scott, J. P. Angew. Chem. Int. Ed. 2000, 39, 377.Paterson, I.; Arnott, E. A. Tetrohedron Lett. 1998, 39, 7185.Paterson, I.; Wallace, D. J.; Cowden, C. J. Synthesis 1998, 639.
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Synthesis of trisubstituted (Z)-alkeneSchreiber
TBSO OTBS
KHMDS,(CF3CH2O)2POCHMeCO2Me
TBSO OTBS
CO2Me
Sch-5 Sch-8
O
(Still-Gennari HWE olefination)93%, Z:E >20:1
14
H
OTBSO
PMBO
(Zhao-Wittig olefination)46%, 3 steps, Z:E = 8-17:1 TBSO
PMBO
I
9
Subunit B
1 Ph3PEtI, n-BuLi, 0oC2 0.1 M I2 in THF, -78oC3 NaHMDS, -23oC
4 Add 6, -33oC13 14
Sm-5
Smith
Still, W. C.; Gennari, C. Tetrahedron Lett. 1983, 24, 4405.Chen, J.; Wang, T.; Zhao, K. Tetrahedron Lett. 1994, 35, 2827.
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Synthesis of trisubstituted (Z)-alkenePaterson
OPMBO O
PhSe
1 NaIO4, NaHCO3 MeOH, H2O, rt
2 DBU, xylene, reflux 82%
OO
MePMBO
Me
++
O
MePMBO
MeO 3 steps, 81%
OTBS
PMBO
OAcO
O
PMBO
O
169
9
11 13
9
15
Subunit B
[3, 3]
14
Burton, J. W.; Clark, J. S.; Derrer, S.; Stork, T. C.; Bendall, J. G.; Holmes, A. B. J. Am. Chem. Soc. 1997, 119, 7483.
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Synthesis of terminal (Z)-dieneSchreiber
TBSO OPMB
I Pd(PPh3)4H2C CHZnBr
80% TBSO OPMB
Sch-6 Sch-7
NaHMDSPh3P+CH2I I-
TBSO OH(Stork-Zhao Wittig olefination)
O75%
OPMBO
OTBS
TrOTBS
O Ph2P Ti(OiPr)4Lithen MeI
76%, 2 steps Z:E = 12:1 OPMBO
OTBS
TrOTBS
Yamamoto Olefination
21 24
9
Sm-8
Sch-4
Sm-7
Smith
1. Stock, G.; Zhao, K. Tetrahedron Lett. 1989, 30, 2173. Ikeda, Y.; Ukai, J.; Ikeda, N.; Yamamoto, H. Tetrahedron 1987, 43, 723.
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Synthesis of terminal (Z)-diene
Paterson
TBSO H
OPMBO
TBSO
OHPMBO
SiMe3
LnCr SiMe3
KH, 98%
Z:E = > 20:1 TBSO
OPMB
11 12
13
Nozaki-Hiyamaallylation
Peterson elimination
24
Takai, K.; Kuroda, T.; Nakatsukasa, S.; Oshima, K.; Nozaki, H. Tetrahedron Lett. 1985, 26, 5585.Aicher, T. D.; Kishi, Y. Tetrahedron Lett. 1987, 28, 3463.Ager, D. Org. React., 1990, 38, 1.
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Fragment couplingSchreiber
0.011% NiCl2/CrCl2, 65%2:1 dr at C7
O
OTBS
PhS
OTBS
HO OPiv
5 steps
O
OTBS
PhS
OTBS
TBSO Br
LDA (1.1 eq), THF, 0oC65%
O
OTBS
O OPMBPhS
OTBS
TBSO
O
OTBS
H
O
PhS
O OPMB
OTBS
I
OPiv8
15
71
1
15
16 2415
1
2415
7
9
1110
Subunit B
A
(Nozaki-Kishi coupling)16
C
O
OTBS
OPhS
OTBS
TBSO
LiN(SiMe2Ph)2 (5 eq)MeI, 47%
3:1 dr at C16
16
24
12
19
Takai, K.; Kuroda, T.; Nakatsukasa, S.; Oshima, K.; Nozaki, H. Tetrahedron Lett. 1985, 26, 5585.Aicher, T. D.; Kishi, Y. Tetrahedron Lett. 1987, 28, 3463.
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Fragment couplingSmith
O OTBSO
I
PMP
1 ZnCl2 (1.15 eq.)2 t-BuLi (3.45 eq.), -78oC to rt
TBSO
PMBOI
3 Pd(PPh3)4 (0.05 eq.), 66% O OO
PMPOTBSTBS
8 steps15
1414
19
subunit Csubunit B
6PMBO
OPMBO
OTBS
-IPh3+P
TBS
NaHMDS (0.95 eq.), THF, -20oC
OO
OTBS
OTBS
O
H
(1.05 eq.)
69%Z:E = 24:1
O
OTBS
O OPMBO
OTBS
TBSO
TBS
89
924
10
11
A
8
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Fragment couplingPaterson
PMBO
O O
OTBS
PMBO
OTBS
OH OPMB
HO1 LiTMP, LiBr2 LiAlH4, 62%> 30:1 dr
16
Subunit C
1716
Subunit B16
H
OPMBO
1724
OTBS
O OTBS
NH2
OOTBS
O OTBS
NH2
OOMeO2C
OTBS
O
H
(+)-Ipc2BCl
87%, 5:1 at C77 7
2
24
17
HO
MeO2CTBSO O
61
Subunit A
9 steps
18
Paterson, I.; Goodman, J. M.; Lister, M. A.; Schumann, R. C.; McClure, C. K.; Norcross, R. D.Tetrahedron, 1990, 46, 4663.Mulzer, J.; Berger, M. J. Am Chem. Soc. 1999, 121, 8393.
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ImprovementSmith
OPMBO
OTBSTBS
9 OPMBO
OTBS
-IPh3+P
TBS9
1 PPh3, I22 PPh3, i-Pr2NEt 12.8 kbar, 6d 82%, 2 steps
12.8 kbar = 12600 atm = 186,000 psi !!
H
OTBSMe
Me
I
HR
HH
OTBSMe
MeH
HH
I -R
+
R
TBSO
R
TBSO
+
OH
OPMBO
OMOMTBS
9 OPMBO
OMOM
-IPh3+P
TBS9
1 PPh3, I22 PPh3, i-Pr2NEt, 100oC 70%, 2 steps
ambient pressureOH
11 11
1111
2nd Generation: ultrahigh pressureUndesired intramolecular cyclization
3rd Generation: improvementReduction of the steric bulk at C11
Smith, A.B. III; Kaufman, M. D.; Beauchamp, T. J.; LaMarche, M. J.; Arimoto, H. Org. Lett. 2003, 5, 4405.
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Paterson 1st generationProblem
OTBS
O OTBS
NH2
OOTBS
O OTBS
NH2
OOMeO2C
OTBS
O
H
(+)-Ipc2BCl
87%, 5:1 at C7
H HO
H Me
RL
Nu
++
7 7
2
24
17
18a: R1 = OH, R2 = H18b: R1 = H, R2 = OH (desired)
Hreagent 18a : 18b yield
c-Hex2BCl 7 : 1 67%(+)-Ipc2BCl 1 : 5 87%
R1R2
MeO2CTBSO O
61
710
10
18
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Paterson 2nd Generation
100% substrate controlO
OH
OH O
NH2
OO
OH
HO
TBSO
O OPMB
H
MeO2CTBSO O
O
H
PMBO
OArO
PMBO
OH
OH O
NH2
O
O
OH
OHPMBO
boron aldol
61
lithium aldol
56 11
1624
24
9
14
1524
16
boron aldol
Still-GennariHWE olefination
1
alkylationA
B
C
common precursor 19
56
+
+
5
reduced overall steps from 42 to 35
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Paterson 2nd Generation
Improvement
OTBS
O O
O
NH2
OTBS
O
B
L
L
+
++
-O
HH
R
cHex2BCl, Et3N
64%, 20:1 dr at C5HO
OTBS
O O
NH2
O
OH
O
TBSMeO2C
RL
616
10
10
19
20
5
8 24
Subunit A
MeO2CTBSO O
H51
Paterson, I.; Delgado, O.; Florence, G. J.; Lyothier, I.; Scott, J. P.; Sereinig, N. S. Org. Lett. 2003, 5, 35.
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Strategy by Novartis
O
OH
OH O
NH2
OO
OH
HO
boron aldol (Paterson)
O O
16
9
14
18
6N
OO
TBS OH
OH O
NH2
O
Mg2+-chelated aldol (novel)
9
14
18MeO2C+
OH
O
9
13
MeO2C
24
18
O
H 19
Zhao-Wittig Olefination(Smith)
Negishi coupling(Smith)
Nozaki-Hiyama/Peterson elimination(Paterson)
OH
PMBO
Roush Crotylation(Schreiber)
O
PMBO H
O
PMBO H
+
CO2MeHO
CO2MeHO
commercially available
Francavilla, C.; Chen, W.; Kinder, F. R. Jr. Org. Lett., 2003, 5, 1233.
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Next Generation ???
10.3%
6%
N.A.21Novartis
23Paterson
2.2%29Marshall
1.4%25Myles
24Smith
4.3%24Schreiber
YieldStepsLongest Linear Sequences
Despite considerable synthetic efforts, there continues to be a pressing demand for a more practical and scaleable total synthesis …
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SAR SummaryAntiproliferative Potencies (IC50, nM) Against A549 or MG63 Cells of Discodermolide (1), and Analogues 2-3e.
A549 MG63Discodermolide 1 3.6 6
(R = Me)2 (R = H; 16-demethyl) n.d. 10
Acetylated analogues:3a (3-OAc) 3.83b (7-OAc) 0.83c (3,7-OAc) 0.83d (3,11-OAc) 1643e (3,17-OAc) 524
OO
OH
HO
OH
R
OH O
NH2
O
3
711
1617
N. Choy, Y. Shin, P. Q. Nguyen, D. P. Curran, R. Balanchandran, C. Madiraju, B. W. Day, J. Med. Chem., 2003, 46, 2846-2864.Nerenberg, J. B.; Hung, D. T.; Schreiber, S. L. J. Am. Chem. Soc. 1996, 118, 11054.Gunasekera, S. P.; Longley, R. E.; Isbrucker, R. A. J. Nat. Prod. 2001, 64, 171.
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SAR SummaryAntiproliferative Potencies (IC50, nM) Against A549 Cells of Discodermolide (1), and Analogues 4a-4d.
OO
R
OH
OH O
NH2
O
3
7OO
OH
HO
OH
OH O
NH2
O14
A5494a (14-cis, demethyl) 7.84b (14-trans, demethyl) 485
A5494c (3-dehydro, R = OH) 1.84d (3-dehydro, R = H) 11.4
Martello, L. A.; LaMarche, M. J.; He, L.; Beauchamp, T. J.; Smith, A. B. III; Horwitz, S. B. Chem. Biol. 2001, 8, 843.
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Summary
Discodermolide, a marine natural product, shares the same microtubule-stabilizing mechanism as Taxol and has a promising anticancer profile.
However, the supply problem is still hampering further biological and SAR studies. To date, total synthesis is the only economical means of providing useful quantities of Discodermolide. Despite considerable synthetic efforts, there continues to be a demand for a more practical and scaleable total synthesis.
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Acknowledgements
Prof. Stephen F. Nelsen, Prof. Steven D. Burke
Brian Lucas, Andy Hawk
Dr. Jian Hong, Dr. Lei Jiang
Dr. Stuart Rosenblum, Dr. Michael Wong, Dr. Ron KuangLei Chen, Dr. Gopinadhan Anilkumar