Antitumor activity of diethynylfluorene derivatives of gold(I)

Article abstract of DOI:10.1016/j.bmc.2009.10.034

A list of diethynylfluorenes and their gold(I) derivatives have been studied for their antitumor activity as a function of their structure-activity relationships. End-capping the fluoren-9-one unit with gold(I) moieties could significantly strengthen the

Full text of DOI:10.1016/j.bmc.2009.10.034

Bioorganic & Medicinal Chemistry 17 (2009) 7872–7877
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Antitumor activity of diethynylfluorene derivatives of gold(I)
Chung-Hin Chui a,b, Raymond Siu-Ming Wong b, Roberto Gambari c, Gregory Yin-Ming Cheng b,
Marcus Chun-Wah Yuen a, Kit-Wah Chan b, See-Wai Tong b, Fung-Yi Lau b, Paul Bo-San Lai d,
e,
e,
*
Kim-Hung Lam a, Cheuk-Lam Ho e, Chi-Wai Kan a, , Kelvin Sze-Yin Leung , Wai-Yeung Wong
*
*
a Institute of Textiles and Clothing, Hong Kong Polytechnic University, Hung Hom, Hong Kong, People’s Republic of China
b Department of Medicine and Therapeutics, Li Ka Shing Medical Sciences Building, Prince of Wales Hospital, The Chinese University of Hong Kong,
Hong Kong, People’s Republic of China
c BioPharmaNet, Department of Biochemistry and Molecular Biology, The University of Ferrara, Ferrara, Italy
d Department of Surgery, Li Ka Shing Medical Sciences Building, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, People’s Republic of China
e Department of Chemistry, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, People’s Republic of China
a r t i c l e i n f o
a b s t r a c t
Article history:
A list of diethynylfluorenes and their gold(I) derivatives have been studied for their antitumor activity as
a function of their structure–activity relationships. End-capping the fluoren-9-one unit with gold(I) moi-
eties could significantly strengthen the cytotoxic activity in vitro on three human cancer cell lines with
induction of reactive oxygen species generation on Hep3B hepatocellular carcinoma cells and exhibit
attractive antitumor activity from in vivo nude mice Hep3B xenograft model with limited adverse effects
on vital organs including liver and kidney.
Received 20 August 2009
Revised 15 October 2009
Accepted 15 October 2009
Available online 21 October 2009
Keywords:
Alkynes
Ó 2009 Elsevier Ltd. All rights reserved.
Fluorenes derivatives
Gold(I) complexes
Human carcinoma cells
Nude mice model
Reactive oxygen species
1. Introduction
this has stimulated considerable interest in searching for new
metal complexes as modern therapeutics and diagnostic agents.
There is continuing research interest in the development of
carbon-rich organic and organometallic compounds containing
However, in light of the undesirable side effects of CDDP in clin-
ical uses, there have been extensive recent studies to develop
new metal-based drugs with less drug resistance and fewer side
effects.14,15 According to the works by Che, Guo, Lippard, Sadler
and others, there has been a growing interest in the chemistry
community to investigate the anticancer activities of gold(I, III),
iron(II), platinum(II), ruthenium(II, III) and vanadium(IV) com-
plexes.10–12,16–19 While many gold(III) complexes20–25 including
gold(III) porphyrins26–29 and cyclometalated gold(III) com-
plexes30,31 have displayed interesting anticancer potencies, their
medicinal applications have always been hampered by their poor
stability in solution.10–12,20,21 Examples of metal arylacetylide as
antitumor agents are very scarce.32 Upon ethynylation by suit-
able ligands, the water-soluble [Pt(terpy)(glycosylated arylacety-
lide)]+ (terpy = terpyridine ligand) was shown to be at least
eightfold more cytotoxic than [Pt(terpy)Cl]+.32
rigid,
p-conjugated chains, due to their widespread and multi-
functional applications in the field of materials science.1–4 We
and others have extensively studied a series of metal acetylide
complexes and polymers.5–9 However, little information is re-
ported about the potential uses of these functional molecules
from the biological and medicinal points of view, including any
possible therapeutic actions, that could be complementary to or-
ganic compounds.10–12 Medicinal inorganic chemistry began to
develop as an up-and-coming scientific discipline after the ser-
endipitous discovery of the antitumor activity followed by the
successful clinical applications of cisplatin (CDDP).13 Since then,
In this contribution, a list of diethynylfluorenes and their gold(I)
derivatives have been studied for the first time for their antitumor
activity using Hep3B human hepatocellular carcinoma cells,
SKHep-1 human hepatoma cells and MDA-MB-231 human breast
cancer cells (Fig. 1).
* Corresponding authors. Tel.: +852 2766 6531; fax: +852 2773 1432 (C.-W.K.);
tel.: +852 3411 5297; fax: +852 3411 7348 (K.S.-Y.L.); tel.: +852 3411 7074; fax:
+852 3411 7348 (W.-Y.W.).
E-mail addresses: tccwk@inet.polyu.edu.hk (C.-W. Kan), s9362284@hkbu.edu.hk
(K.S.-Y. Leung), rwywong@hkbu.edu.hk (W.-Y. Wong).
0968-0896/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2009.10.034

C.-H. Chui et al. / Bioorg. Med. Chem. 17 (2009) 7872–7877
7873
NC CN
O
4
1
O
O
Au(PPh3)
Au(PPh3)
(Ph3P)Au
(Ph3P)Au
2
5
O
3
6
Figure 1. Chemical structures of organic diethynylfluorenes (1–4) and their gold(I) derivatives (5 and 6).
minary structure–activity relationship could be observed. The
presence of phenyl and tolyl end groups could significantly reduce
the cytotoxic activity of 2–4 relative to the free alkyne 1. The ef-
fects of electron-withdrawing carbonyl and dicyanomethylene
groups on the cytotoxicity of organic diethynylfluorene do not dif-
fer very much. However, non-metallic diethynylfluorenes 1–4 did
not show better cytotoxicity than our positive reference, CDDP,
2. Results and discussion
2.1. Synthetic chemistry
Scheme 1 summarizes the reaction steps leading to the target
compounds in this study. Organic model compounds 2 and 3 were
obtained by the Sonogashira type coupling between 2,7-dibromo-
fluorenes and the appropriate 1-alkyne in good yields.33 The dicy-
ano-substituted compound 4 was prepared from 3 by thermal
reaction with malononitrile in DMSO. The digold(I) bis(acetylide)
complexes were synthesized from the base-catalyzed dehydro-
halogenation between Au(PPh3)Cl and 1 or 2,7-diethynylfluorene
in the presence of NaOH in MeOH.34 All the compounds were ob-
tained as air-stable solids in high purity and found to be soluble
in chlorinated solvents such as CH2Cl2 and DMSO.
at 50 lM.
Wealso looked into thegold(I) congenerof 1 (i.e., 5) and its parent
species without the carbonyl unit (6). Compound 5 showed superior
cytotoxicity on the three human cancer cell lines tested. To ascertain
our assumption, we also tested the possible biological activity of the
non-carbonyl derivative of gold(I). As anticipated, 6 was nearly non-
cytotoxic at 50 lM, akin to the organic pair (i.e., 3 vs 4). Substitution
ofthecarbonylgroupin5 withaCH2 fragmentin6 wouldcompletely
diminish its cytotoxicity, suggesting the key role played by the C@O
group in designing the most effective agent.
2.2. Biology
Since complex 5 has the best potential to be further developed
to be anticancer regimen, we tried to determine its IC50 against the
three human cancer cell lines using sulforhodamine B assay.35 Its
As shown in Table 1, the mean cytotoxicity at 50 lM towards
these three human carcinoma cell lines follows the trend
5 ꢀ CDDP > 1 > 2 > 3 but the values are quite comparable among
the less effective compounds 3, 4 and 6 within statistical limits.
When only non-metallic compounds are considered, some preli-
mean IC50 was found to be ꢁ1.7
l
M for Hep3B, ꢁ4.7
lM for
SKHep-1 and ꢁ5.1
l
M for MDA-MB-231 after 48 h of incubation
(Table 1). Compound 5 is 7–9-fold more cytotoxic than CDDP,
O
O
(i)
R =
Ph
Me-C6H4
2
3
R
R
Br
Br
(ii)
CN
NC
R
R
R = Me-C6H4
4
O
O
(iii)
(iii)
Au(PPh3)
Au(PPh3)
(Ph3P)Au
(Ph3P)Au
5
1
6
Scheme 1. Reagents and conditions: (i) phenylacetylene or tolylacetylene, Pd(OAc)2, PPh3, CuI, iPr2NH; (ii) CH2(CN)2, DMSO, 110 °C; (iii) Au(PPh3)Cl, NaOH, MeOH.

7874
C.-H. Chui et al. / Bioorg. Med. Chem. 17 (2009) 7872–7877
Table 1
(Upper) Percentage of survival cells after treating with different diethynylfluorenes and their gold(I) derivatives at 50
l
M after 48 h of incubation
1
2
3
4
5
6
CDDP
Hep3B
MDA-MB-231
SKHep-1
78.1 4.6
81.4 3.4
77.6 5.1
85.0 2.5
90.3 1.6
84.8 5.3
Hep3B
94.9 3.1
97.5 1.4
92.2 2.5
99.8 2.4
103.6 3.7
101.0 4.7
4.6 1.8
9.1 2.5
5.8 0.5
96.7 4.1
101.6 2.7
99.8 5.4
39.5 3.0
72.7 3.8
44.0 1.6
SKHep-1
MDA-MB-231
5
1.7 1.4
38 4.2
5.1 2.6
78 4.6
4.7 1.5
41 2.8
CDDP
CDDP was used as a positive reference. Three independent experiments were performed and similar results were obtained. Results represent the mean SD from one
representative experiment. (Lower) IC50 values of 5 against three human carcinoma cell lines as determined by sulforhodamine B assay expressed in micro-molarity [ M]
l
after 48 h of incubation. CDDP was used as a positive reference. Three independent experiments were performed and similar results were obtained. Results represent the
mean standard derivation from one representative experiment.
and IC50 values of 5 are 8–22-fold smaller than the reference
standard.
The in vitro data enhance our tendency to investigate its in vivo
antitumor activity. Athymic nude mice xenografted with human
Hep3B carcinoma cells were employed as a tool for this purpose.
Mice with Hep3B cancer cells xenografted of average tumor vol-
ume about 200 mm3 received intraperitioneal injection daily of
either 50 l
L of buffer vehicle or equal volume of 5 at 2.5 mg kgꢂ1
for nine consecutive days. As shown in Figure 2, the mean tumor
volume of 5-treated mice began to reduce on day 6, and on day
10, their tumor size returned to the initial mean tumor volume
while there was more than a triple increment for vehicle control
group. A general increase in body weight was observed from both
vehicle treated mice and 5-treated mice (Fig. 3).
In order to determine whether 5 has any possible toxicology ef-
fects in the internal vital organs of mice under the current thera-
peutic protocol, autopsies of vital organs including livers and
kidneys were examined for their anatomy. We found that no obser-
vable necrotic features were found from autopsy samples of all the
10 mice (Fig. 4). Further plasma liver functional enzymes analysis
including alanine aminotransferase (ALT) and asparate amino-
transferase (AST) showed normal liver functions from these 10
mice as well (Table 2).
We also prepared the tumor section for histochemistry study.
However, after the embedding procedure, we found that the tissues
were completely damaged because of the extensive necrosis caused
by 5, which provided direct evidence for the therapeutic effect of 5.
Figure 3. Changes of body weight (grams) against number of day of mice treated
with vehicle and 5 at 2.5 mg kgꢂ1 for 9 consecutive days. Results are shown as
mean standard derivation. N = 5 from each group.
Understanding the underlying mechanistic working principle is
an important aspect for development of novel therapeutic agent. In
our case, we investigated that the gold(I) complex 5 could induce a
significant generation of intracellular reactive oxygen species
(ROS), as detected by using the 20,70-dichlorofluorescein diacetate
probe, after incubation for 24 h at 10 lM with Hep3B human hep-
atocellualr carcinoma cells. Preliminary data suggested that the
presence of gold in 5 could be involved in the generation of ROS
as 1 was unable to stimulate the production of ROS significantly.
We believe that generation of ROS in 5 is essential for its cytotox-
icity since co-incubation with catalase could partially reverse the
generation of intracellular ROS as well as cytotoxic activity against
Hep3B human carcinoma cells (Fig. 5).36
As further pre-incubation of the Hep3B cancer cells with a pan-
caspase inhibitor, zVADfmk at 20
lM, could not reverse the cyto-
toxicity effect of 5 at 10 M after a further incubation for 24 h, it
l
seems that caspase family members do not play a significant role
in 5-induced Hep3B cell death (data not shown). DNA is one of
the major targets for anticancer drugs, and binding of metallodrugs
to DNA has been extensively studied.29,37–40 Intuitively, similar
interactions may be involved in the presence of gold center in
the present case.
We also examined the relative cellular uptake of 5 and 6. Using
Hep3B cells as a demonstration model and by means of ICP-MS
studies, our results revealed that good uptakes of gold were dem-
onstrated in both 5 and 6. The gold uptake by 5 was about 8 to 18
times more than 6 (from four trials), on average 11 times more, per
Figure 2. Representative results showing the changes of Hep3B tumor volume
(mm3) against number of day of mice treated with vehicle or 5 for 9 consecutive
days from day 1 to day 9. Intraperitoneal injection started for both groups when
mean tumor volume of mice reached ꢁ200 mm3. A total of 10 mice were randomly
divided into two groups. On day 10, after measuring individual tumor volume, all
lg of protein. Thus, a much higher uptake of 5 was observed in the
cells relative to that for 6 and this is apparently a manifestation of
the role of the keto group in 5 to account for its better cytotoxic
effect.
mice were sacrificed for plasma and vital organs collection. Results are shown as
*
)
(
mean standard derivation. Asterisk
indicates that there is a statistical signif-
icance between the considered group with vehicle control (P <0.05).

C.-H. Chui et al. / Bioorg. Med. Chem. 17 (2009) 7872–7877
7875
Figure 4. (A and B) Representative Hep3B xenografted nude mice treated with vehicle (A) or 5 (B) at 2.5 mg kgꢂ1 for 9 consecutive days. The tumor size of Hep3B from A is
much bigger than that of B. (C and D) Histochemistry study of liver section from sacrificed mice of A and B to observe any possible liver toxicity. No necrotic tissue and
damage was discovered. (E and F) Histochemistry study of kidney section from sacrificed mice of A and B to observe any possible kidney toxicity. No necrotic tissue and
damage was discovered.
Table 2
dried and distilled from appropriate drying agents. All chemicals,
unless otherwise stated, were obtained from commercial sources
and used as received. Preparative TLC was performed on 0.7 mm
silica plates (Merck Kieselgel 60 GF254) prepared in our laboratory.
The starting materials 2,7-bis(trimethylsilylethynyl)fluorene,41–43
Plasma liver enzyme assays for vehicle control and 5-treated Hep3B xenografted
athymic nude mice
Vehicle
5
Reference
ALT
AST
49.6 5.3
78.2 29.6
46.6 7.2
89.6 20.6
28–132
59–246
2,7-diethynylfluorene,41–43
2,7-bis(trimethylethynyl)fluoren-9-
one,41 and 2,7-diethynylfluoren-9-one (1)41 were prepared by the
literature methods. Infrared spectra were recorded as KBr pellets
using a Perkin Elmer Paragon 1000 PC or Nicolet Magna 550 Series
II FTIR spectrometer. NMR spectra were measured in appropriate
solvents on a JEOL EX270 or a Varian INOVA 400 MHz FT-NMR
spectrometer, with 1H NMR chemical shifts quoted relative to the
TMS standard. Electron impact (EI) and fast atom bombardment
(FAB) mass spectra were recorded on a Finnigan MAT SSQ710 mass
spectrometer.
N = 5 for both vehicle control group and 5-treated group. Enzymatic levels were
determined by the IDEXX laboratories machine using its veterinary biochemistry
assay kits and expressed as units per liter. Results represent the mean standard
derivation.
3. Conclusions
In summary, this contribution revealed that the dinuclear
gold(I) species containing a fluorenone group 5 was shown to pos-
sess a significant biological activity both in vitro and in vivo. This
compound is of significance in that it exhibits noticeably potent
cytotoxic activity on human cancer cells and provides an additional
example of metal arylacetylide complexes with impressive antitu-
mor activities, which are still very scarce. It also highlights the
prospect of gold(I) acetylides as another promising lead for anti-
cancer metallodrug development. The generation of ROS from the
carbonyl group of the central ligand spacer is believed to be essen-
tial for the cytotoxicity of 5. This is suggested from consideration of
structure–activity relationships between compounds tested, and
supported by an experiment using catalase. Our findings also pro-
vide a platform of organic skeleton for conjugation with other met-
als to synthesize a variety of organometallic derivatives for other
biological applications.
4.2. ICP-MS analysis
The amount of gold uptake was compared among the two sam-
ples (5 and 6) and the control (vehicle) using ICP-MS [ELAN DRC II
ICP-MS (PerkinElmer, Waltman, MA, USA)]. Briefly, after incubating
the Hep3B cells with these compounds at 50 lM for 2 h, Hep3B
cells were subsequently washed twice with physiological buffered
saline and total cellular protein was extracted by lysis buffer. The
protein concentration was determined by Bradford’s assay. The
protein samples were diluted, filtered and injected right away for
semi-quantitative analysis of gold.
4.3. Syntheses
4. Experimental
4.1. General
The syntheses of compounds followed the procedures reported
recently.33,34
4.4. Cancer cell culture
All reactions were carried out under nitrogen atmosphere with
the use of standard Schlenk techniques, but no special precautions
were taken to exclude oxygen during work-up. Solvents were pre-
The human cancer cells Hep3B (HB-8064), MDA-MB-231 (HTB-
26) and SKHep-1 (HTB-52) were obtained from American Type of

7876
C.-H. Chui et al. / Bioorg. Med. Chem. 17 (2009) 7872–7877
Figure 5. Human liver cancer cells Hep3B were treated with (A) vehicle control, (B) 5 at 10 lM for 24 h, (C) 5 at 10 lM and catalase 1000 units for 24 h and stained with
sulforhodamine B. Compound 5 induced significant morphology changes including cell rounding, bubbling of cell membrane and shrinkage. Co-incubation of 5 with catalase
could preserve some cancer cells from 5-induced cell death. (D) Relative folds of generation of ROS as detected by 20,70-dichlorofluorescein diacetate from different treatment
*
of Hep3B cancer cells where ‘vehicle control’ is defined as ‘1’. Results are shown as mean SD from three independent experiments. Asterisk ( ) indicates that there is a
statistical significance between the considered group with vehicle control (P <0.05).
Culture Collection. They were cultured in RPMI-1640 medium with
5% fetal bovine serum (complete cell culture medium) at 37 °C in
5% CO2 humidified incubator.
tometer under an inverted microscope. After 24 h, the culture
medium was changed and incubated with compound 5 with or
without catalase. After a further incubation of 24 h, the culture
medium was changed and cells were incubated with 20,70-dichloro-
fluorescein diacetate (Molecular Probe) for a further of 30 min.
Cancer cells were washed and collected. Cells were subsequently
lysed and total cellular protein was collected while debris was dis-
carded. Protein content was determined by using the Bradford re-
4.5. Sulforhodamine B assay for cell viability
Cancer cells were removed from 75 mL sterile cell culture flasks
with trypsin and neutralized with fetal bovine serum. After wash-
ing with phosphate buffered saline and centrifugation, cancer cells
were re-suspended in complete cell culture medium at a concen-
tration of approximately 1 ꢃ 105 cells/mL and counted manually
using a haematocytometer under an inverted microscope. Cancer
cells seeded in the 96 wells microtitre plates for 24 h were pre-
pared for the screening of the synthesized compounds. The com-
pounds were dissolved in molecular biology grade DMSO at a
stock concentration of 50 mM. CDDP was used as the positive ref-
agent. The relative level of ROS from each of 20 lg of total protein
sample was determined by measuring its fluorescence units at
515 nm after an excitation at 485 nm using a microplate reader.
4.7. Caspases inhibition assay
Hep3B cancer cells were seeded at a concentration of approxi-
mately 1 ꢃ 105 cells/mL and counted manually using a haematocy-
tometer under an inverted microscope. After 24 h, the culture
medium was changed and cells were pre-incubated with pan-cas-
pase inhibitor (zVADfmk from Promega) for 2 h before adding com-
pound 5. After a further incubation of 24 h, cellular viability was
determined by the sulforhodamine B protein staining methods as
mentioned above.
erence compound and added at a starting concentration of 50
lM.
Compounds were added at a starting concentration of 50 M fol-
l
lowed by a serial of twofold dilutions and incubated with cells
for a further period of 48 h. Afterwards, the evaluation of possible
anti-proliferative potential of our synthesized compounds was per-
formed by the sulforhodamine B protein staining methods. Briefly,
cancer cells were fixed with trichloroacetic acid, washed and
stained with sulforhodamine B. Afterwards, cells were washed
again with acetic acid and stained cells were dissolved in unbuf-
fered Tris-base. Finally, optical absorptions were measured at
575 nm using a microplate reader (Victor V form Perkin Elmer, Life
Sciences). The 50% inhibitory concentrations of compounds and
CDDP were calculated from these experimental results.
4.8. In vivo athymic nude mice experiment
Eight weeks old athymic nude mice, weighing approximately
15–20 g, were purchased from the animal unit of The Chinese Uni-
versity of Hong Kong and maintained in a sterile facility, in accor-
dance with the institutional guidelines on animal care, with the
required consistent temperature and relative humidity. All the pro-
cedures were approved by the Animal Research Ethics Committee.
Ten athymic nude mice were injected subcutaneously with the hu-
man hepatocellular carcinoma Hep3B cells. They were housed in a
sterile condition. Tumor size was measured by the electronic
4.6. Determination of ROS
Hep3B cancer cells were seeded at a concentration of approxi-
mately 1 ꢃ 105 cells/mL and counted manually using a haematocy-

C.-H. Chui et al. / Bioorg. Med. Chem. 17 (2009) 7872–7877
7877
13. Rosenberg, B.; VanCamp, L.; Trosko, J. E.; Mansour, V. H. Nature 1969, 222, 385.
14. Reedijk, J. Proc. Natl. Acad. Sci. 2003, 100, 3611.
15. Topics in Biological Inorganic Chemistry; Clarke, M. J., Sadler, P. J., Eds.1999;
Springer: Berlin; Vol. 1.
16 C.X.Zhang; S.J.Lippard Curr. Opin. Chem. Biol. 2003, 7, 481.
17. Guo, Z.; Sadler, P. J. Adv. Inorg. Chem. 2000, 49, 183.
18. Guo, Z.; Sadler, P. J. Angew. Chem., Int. Ed. 1999, 38, 1512.
19. Wang, X.; Guo, Z. Dalton Trans. 2008, 1521.
20. Shaw, C. F. Chem. Rev. 1999, 99, 2589.
21. Milacic, V.; Chen, D.; Ronconi, L.; Landis-Piwowar, K. R.; Fregona, D.; Dou, Q. P.
Cancer Res. 2006, 66, 10478.
22. Casini, A.; Cinellu, M. A.; Minghetti, G.; Gabbiani, C.; Coronnello, M.; Mini, E.;
Messori, L. J. Med. Chem. 2006, 49, 5524.
23. Berners-Price, S. J.; Mirabelli, C. K.; Johnson, R. K.; Mattern, M. R.; McCabe, F. L.;
Faucette, L. F.; Sung, C. M.; Mong, S. M.; Sadler, P. J.; Crooke, S. T. Cancer Res.
1986, 46, 5486.
24. Barnard, P. J.; Berners-Price, S. J. Coord. Chem. Rev. 2007, 251, 1889.
25. Articles in the issues 11 and 12, Coord. Chem. Rev. 2009, 253.
26. Lum, C. T.; Yang, Z. F.; Li, H. Y.; Sun, R. W. Y.; Fan, S. T.; Poon, R. T. P.; Lin, M. C.
M.; Che, C. M.; Kung, H. F. Int. J. Cancer 2006, 118, 1527.
27. Wang, Y.; He, Q. Y.; Che, C. M.; Chiu, J. F. Proteomics 2006, 6, 131.
28. Wang, Y.; He, Q. Y.; Sun, R. W. Y.; Che, C. M.; Chiu, J. F. Cancer Res. 2005, 65,
11553.
calliper daily. When tumor size reached a mean volume of about
200 mm3 where tumor volume was calculated by the formula
(length ꢃ width ꢃ width)/2, they were randomly divided into two
groups. Compound at
a
concentration of 2.5 mg kgꢂ1 body
weight/day was administrated intraperitoneally for a continuous
period of 9 days starting from day 1. Each group consisted of 5 mice.
Body weight of each animal was also recorded. On day 10, mice
were sacrificed and H and E staining of autopsy analysis including
livers and kidneys from all the 10 animals were investigated for
any possible significant toxicology effects including occurrence of
any necrotic tissue. Whole blood was also collected and plasma li-
ver enzymes including ALT and AST were measured by the Vet bio-
chemistry assay kits for the IDEXX laboratories machine to
determine whether there are any liver failure phenomena from
both groups of mice by comparing with the normal control ranges.
Acknowledgments
29. Che, C. M.; Sun, R. W. Y.; Yu, W. Y.; Ko, C. B.; Zhu, N.; Sun, H. Chem. Commun.
2003, 1718.
30. Li, C. K.; Li, L.; Sun, R. W. Y.; Kui, S. C. F.; Zhu, N.; Che, C. M. Chem. Eur. J. 2006,
12, 5253.
31. Wong, K. H.; Cheung, K. K.; Chan, M. C. W.; Che, C. M. Organometallics 1998, 17,
3505.
32. Ma, D. L.; Shum, T. Y. T.; Zhang, F.; Che, C. M.; Yang, M. Chem. Commun. 2005,
4675.
33. Wong, W.-Y.; Lu, G.-L.; Choi, K.-H.; Lin, Z.-Y. Eur. J. Org. Chem. 2003, 365.
34. Wong, W.-Y.; Choi, K.-H.; Lu, G.-L.; Shi, J.-X.; Lai, P.-Y.; Chan, S.-M.; Lin, Z.-Y.
Organometallics 2001, 20, 5446.
35. Lu, G. L.; Ho, C. L.; Wang, Q.; Wong, W.-Y.; Chui, C. H.; Wong, R. S. M.; Gambari,
R.; Lau, F. Y.; Yuen, M. C. W.; Tong, C. S. W.; Chan, A. K. W.; Tang, J. C. O.; Ho, K.
P.; Cheng, G. Y. M. Aust. J. Chem. 2008, 61, 975.
The authors wish to acknowledge the financial support to this
work from The Hong Kong Polytechnic University to C.-W. Kan
(A-PD1G). W.-Y. Wong would like to acknowledge the Hong Kong
Research Grants Council (HKBU 202106) and Hong Kong Baptist
University (FRG/08-09/I-20) for financial support. C.-H. Chui is sup-
ported by the Assistant Professorship kindly offered by Prof. X.-M.
Tao. R. Gambari is sponsored by AIRC (Italian Association for Can-
cer Research).
References and notes
36. Chui, C. H.; Lau, F. Y.; Chan, A. S. C.; Cheng, G. Y. M.; Wong, R. S. M.; Lai, K. B.;
Kok, S. H. L.; Au Yeung, T. T. L.; Teo, I. T. N.; Yau, M. Y. C.; Cheung, F.; Cheng, C.
H.; Tang, J. C. O. Int. J. Mol. Med. 2005, 15, 539.
37. Hurley, L. H. Nat. Rev. Cancer 2002, 2, 188.
38. Lipscomb, L. A.; Zhou, F. X.; Presnell, S. R.; Woo, R. J.; Peek, M. E.; Plaskon, R. R.;
Williams, L. D. Biochemistry 1996, 35, 2818.
39. Lewis, J.; Raithby, P. R.; Wong, W.-Y. J. Organomet. Chem. 1998, 556, 219.
40. Fricker, S. P. Gold Bull. 1996, 29, 53.
41. Ni Dhubhghaill, O. M.; Sadler, P. J. In Metal Complexes in Cancer Chemotherapy;
Keppler, B. K., Ed.; VCH: Weinheim, 1993; p 221.
42. Wong, W.-Y.; Wong, W.-K.; Raithby, P. R. J. Chem. Soc., Dalton Trans. 1998, 276.
43. Wong, W.-Y.; Lam, H.-Y.; Lee, S.-M. J. Organomet. Chem. 2000, 595, 70.
1. Yamamoto, T. Macromol. Rapid Commun. 2002, 23, 583.
2. Kingsborough, R. P.; Swager, T. M. Prog. Inorg. Chem. 1999, 48, 123.
3. Stott, T. L.; Wolf, M. O. Coord. Chem. Rev. 2003, 246, 89.
4. Bunz, U. H. F. Chem. Rev. 2000, 100, 1605.
5. Wong, W. Y.; Ho, C. L. Coord. Chem. Rev. 2006, 250, 2627.
6. Wong, W. Y. Dalton Trans. 2007, 4495.
7. Long, N. J.; Williams, C. K. Angew. Chem., Int. Ed. 2003, 42, 2586.
8. Nguyen, P.; Gómez-Elipe, P.; Manners, I. Chem. Rev. 1999, 99, 1515.
9. Yam, V. W. W. Chem. Commun. 2001, 789.
10. Sun, R. W. Y.; Ma, D. L.; Wong, E. L. M.; Che, C. M. Dalton Trans. 2007, 4884 and
references therein.
11. Bruijnincx, P. C. A.; Sadler, P. J. Curr. Opin. Chem. Biol. 2008, 12, 197.
12. Hartinger, C. G.; Dyson, P. J. Chem. Soc. Rev. 2009, 38, 391.