Academic literature on the topic 'Tryptanthrin'

Tuberculosis (TB), caused by Mycobacterium tuberculosis, is a global burden, responsible for over 1 million deaths annually. The emergence and spread of drug-resistant M. tuberculosis strains (MDR-, XDR- and TDR-TB) is the main challenge in global TB-control, requiring the development of novel drugs acting on new biotargets, thus able to overcome the drug-resistance. Tryptanthrin is a natural alkaloid, with great therapeutic potential due to its simple way of synthesis and wide spectrum of biological activities including high bactericidal activity on both drug-susceptible and MDR M. tuberculosis strains. InhA was suggested as the target of tryptanthrins by in silico modeling, making it a promising alternative to isoniazid, able to overcome drug resistance provided by katG mutations. However, neither the mechanism of action of tryptanthrin nor the mechanism of resistance to tryptanthrins was ever confirmed in vitro. We show that the MmpS5-MmpL5 efflux system is able to provide resistance to tryptanthrins using an in-house test-system. Comparative genomic analysis of spontaneous tryptanthrin-resistant M. smegmatis mutants showed that mutations in MSMEG_1963 (EmbR transcriptional regulator) lead to a high-level resistance, while those in MSMEG_5597 (TetR transcriptional regulator) to a low-level one. Mutations in an MFS transporter gene (MSMEG_4427) were also observed, which might be involved in providing a basal level of tryptanthrins-resistance.

ABSTRACT New drugs are needed for treatment of Toxoplasma gondii infections. We tested derivatives of principles found in Isatis indigotica for in vitro efficacy against T. gondii infection. Indirubin-3′-oxime analogs showed modest micromolar activity, while tryptanthrin derivatives displayed 50% inhibitory doses in the low nanomolar range. Tryptanthrins have potential as anti-Toxoplasma infection therapeutics.

Purpose. Tryptanthrin, an indole quinazoline alkaloid with multiple medical activities, has been recently under preclinical development as an anti-tuberculosis and anti-tumor drug. The aims of this study are to characterize the intestinal transport of tryptanthrin in Caco-2 cells, to determine whether P-glycoprotein (P-gp) and multidrug resistance-associated protein 2 (MRP2) are involved in this issue, and to evaluate the potential influence of tryptanthrin on the function of P-gp and MRP2. Methods. Transport assays of tryptanthrin were performed in Caco-2 monolayers with or without the supplement of P-gp and MRP2 inhibitors. Transport assays of P-gp and MRP2 substrates were also performed in the presence of tryptanthrin. The effect of tryptanthrin on the expression of P-gp and MRP2 was analyzed by reverse transcriptase-PCR. Results. Both absorption and secretion of tryptanthrin were concentration-independent at a low concentration range of 0.8–20 µM. The apparent permeability (Papp) for the apical (AP) to basolateral (BL) was 6.138 ± 0.291 × 10-5. The ratio of Papp (BL→AP) to Papp (AP→BL) was 0.77, suggesting greater permeability in the absorptive direction. Both the P-gp inhibitor, verapamil, and the MRP2 inhibitor, glibenclamide, didn’t affect the efflux transport of tryptanthrin. The efflux transport of the P-gp substrate, digoxin, and the MRP2 substrate, pravastatin sodium, decreased when tryptanthrin was present. However, tryptanthrin didn’t change the expression of P-gp and MRP2. Conclusions. Tryptanthrin was well absorbed across the Caco-2 monolayers, and its transepithelial transports were dominated by passive diffusion. Tryptanthrin was not a substrate, but a potential inhibitor of P-gp and MRP2. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

Abstract Tryptanthrin is an indole quinazoline alkaloid from the indigo-bearing plants, such as Isatis indigotica Fort. Typically, this natural compound shows a variety of pharmacological activities such as antitumor, antibacterial, anti-inflammatory and antioxidant effects. This study was conducted to assess the antitumor activity of tryptanthrin in breast cancer models both in vitro and in vivo, and to explore the important role of the inflammatory tumor microenvironment (TME) in the antitumor effects of tryptanthrin. Human breast adenocarcinoma MCF-7 cells were used to assess the antitumor effect of tryptanthrin in vitro. MTT assay and colony formation assay were carried out to monitor the antiproliferative effect of tryptanthrin (1.56~50.0 μmol L−1) on inhibiting the proliferation and colony formation of MCF-7 cells, respectively. The migration and invasion of MCF-7 cells were evaluated by wound healing assay and Transwell chamber assay, respectively. Moreover, the 4T1 murine breast cancer model was established to examine the pharmacological activity of tryptanthrin, and three groups with different doses of tryptanthrin (25, 50 and 100 mg kg−1) were set in study. Additionally, tumor volumes and organ coefficients were measured and calculated. After two weeks of tryptanthrin treatment, samples from serum, tumor tissue and different organs from tumor-bearing mice were collected, and the enzyme-linked immunosorbent assay (ELISA) was performed to assess the regulation of inflammatory molecules in mouse serum. Additionally, pathological examinations of tumor tissues and organs from mice were evaluated through hematoxylin and eosin (H&E) staining. The expression of inflammatory proteins in tumor tissues was measured by immunohistochemistry (IHC) and Western blotting. Tryptanthrin inhibited the proliferation, migration and invasion of MCF-7 cells, up-regulated the protein level of E-cadherin, and down-regulated those of MMP-2 and Snail, as suggested by the MCF-7 cell experiment. According to the results from in vivo experiment, tryptanthrin was effective in inhibiting tumor growth, and it showed favorable safety without inducing the fluctuations of body mass and organ coefficient (p > 0.05). In addition, tryptanthrin also suppressed the expression levels of NOS1, COX-2 and NF-κB in mouse tumor tissues, and regulated those of IL-2, IL-10 and TNF-α in the serum of tumor cells-transplanted mice. Tryptanthrin exerted its anti-breast cancer activities through modulating the inflammatory TME both in vitro and in vivo.

A new series of tryptanthrin analogues have been synthesized as potential antimalarial molecules. Synthesis of tryptanthrin aminoalkyl derivatives have been achieved via alkylation of oxime functionality of tryptanthrin derivatives by various alkyl amino pharmacophoric chains. 21-Membered small library of tryptanthrin aminoalkyl analogues were synthesized with variation in both parent natural alkaloid and in amino alkyl side chains. Synthesized compounds were fully characterized with 1H & 13C NMR, IR spectroscopy. Further all the members were screened for their antimalarial potential against Plasmoum falciparum in both sensitive (3D7) and in resistant (k1) strains. Most of the screened compounds were exhibited potent antimalarial activity in both strains. Compounds (5m, 3c and 5l) having nitro group at the 8 position in tryptanthrin framework were most promising compounds in series (IC50 = 10 nm) with IC50 value as low as 10 nm comparable to chloroquine. These compounds were also tested for their toxic effect and found to be highly safe with very high value of SI index.

Strobilanthes cusia (Nees) Kuntze is a Chinese herbal medicine used in the treatment of respiratory virus infections. The methanol extract of S. cusia leaf contains chemical components such as β-sitosterol, indirubin, tryptanthrin, betulin, indigodole A, and indigodole B that have diverse biological activities. However, the antiviral action of S. cusia leaf and its components against human coronavirus remains to be elucidated. Human coronavirus NL63 infection is frequent among immunocompromised individuals, young children, and in the elderly. This study investigated the anti-Human coronavirus NL63 (HCoV-NL63) activity of the methanol extract of S. cusia leaf and its major components. The methanol extract of S. cusia leaf effectively inhibited the cytopathic effect (CPE) and virus yield (IC50 = 0.64 μg/mL) in HCoV-NL63-infected cells. Moreover, this extract potently inhibited the HCoV-NL63 infection in a concentration-dependent manner. Among the six components identified in the methanol extract of S. cusia leaf, tryptanthrin and indigodole B (5aR-ethyltryptanthrin) exhibited potent antiviral activity in reducing the CPE and progeny virus production. The IC50 values against virus yield were 1.52 μM and 2.60 μM for tryptanthrin and indigodole B, respectively. Different modes of time-of-addition/removal assay indicated that tryptanthrin prevented the early and late stages of HCoV-NL63 replication, particularly by blocking viral RNA genome synthesis and papain-like protease 2 activity. Notably, tryptanthrin (IC50 = 0.06 μM) and indigodole B (IC50 = 2.09 μM) exhibited strong virucidal activity as well. This study identified tryptanthrin as the key active component of S. cusia leaf methanol extract that acted against HCoV-NL63 in a cell-type independent manner. The results specify that tryptanthrin possesses antiviral potential against HCoV-NL63 infection.

Coronaviruses belong to the subfamily Coronavirinae, which are large viruses with a single Ribonucleic acid tape and a nucleocapsid. In a recent study it was found that the molecule of tryptanthrin has antiviral potential against human coronavirus NL63. In this work, we used a combination of theoretical techniques with experimental nuclear magnetic resonance data to assist in the structural characterization of the Tryptanthrin molecule. Tryptanthrin was extracted from Couroupita guianensis leaves. The theoretical calculations of hydrogen-1, homonuclear spin–spin coupling constants and the quantum theory of atoms in molecules were performed employing density functional theory. Our results show that the hydrogen-1 chemical shifts calculated at the gaseous phase and solvent presented similar performance. The quantum theory of atoms in molecules calculations was able to quantify and qualify bonded interactions based on five topological parameters obtained at the analyzed bond critical point to tryptanthrin molecule. We obtained a satisfactory correlation between tryptanthrin delocalization index values and its experimental and calculated proton–proton coupling constants. In conclusion, the theoretical techniques used in this work in combination with NMR experimental data can be a useful tool in aiding the structural determination of organic compounds.

Tryptanthrin is one of the most important members of indoloquinoline alkaloids. We obtained this alkaloid fromIsatis. Two novelFeIIandCoIIcomplexes of tryptanthrin were first synthesized. Single-crystal X-ray diffraction analyses show that these complexes display distorted four-coordinated tetrahedron geometry via two heterocyclic nitrogen and oxygen atoms from tryptanthrin ligand. Binding with G-quadruplex DNA properties revealed that both complexes were found to exhibit significant interaction with G-quadruplex DNA. This study may potentially serve as the basis of future rational design of metal-based drugs from natural products that target the G-quadruplex DNA.

We report an efficient Mukaiyama-aldol reaction of tryptanthrin with fluorinated enol silyl ethers, which is carried out in methanol without the use of any catalyst. This represents the first modification of tryptanthrin by a fluoroalkyl group, which is applied to the total synthesis of the difluoro analogues of the natural product Phaitanthrin B.

碩士
國立臺灣大學
藥學研究所
89
I. The apoptotic activity of tryptanthrin derivatives in MCF7 cells Tryptanthrin, indolo[2,1-b]quinazolin-6,12-dione, is a coplanar four-fused ring compound which contains N-phenyl-quinazoline skeleton similar to 2-phenyl-naphthalene. It was illustrated that compounds containing coplanar 2-phenyl-naphthalene skeleton exhibit different biological activites, while the bioactivities would be decreased or lost in unplanar structures. For example, batracylin, containing 2-phenyl-quinolone skeleton,inhibits the growth of carcinoma cell lines. In previous data, tryptanthrin derivatives with different substituents exert different potency of various bioactivities. It draws our attention to screen tryptanthrin derivatives for cytotoxicity and study their apoptotic activity as potential anticancer agents. In the cytotoxic assay, tryptanthrin derivatives, DQ181, DQ166 and EY093, exert cytotoxic activity in cancer cell lines including MCF7, HeLa, A498, SKOV3 cells. Our data showed that cells undergo apoptosis and die. MCF7 cells are the most sensitive to these tryptanthrin derivatives. DQ181 is the most potent compound of those tryptanthrin derivatives. The result suggested that DQ181 may be a new compound developed to treat breast cancer. We further study the mechanism of apoptosis induced by DQ181. The extensive experiments indicated DQ181-induced apoptosis may be via upregulation of the expression of Fas receptor and Fas ligand, resulting in activating caspase-8 mediated pathway. Fas receptor protein overexpresses in two hours but decrease later. Fas ligand protein expression stimulated by DQ181 was elevated in a time dependent manner。 II. Inhibition of TCDD-induced aryl hydrocarbon receptor translocation by tryptanthrin derivative DQ181 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and related compounds induce a broad spectrum of biochemical and toxic responses including carcinogenesis. Binding of TCDD to Ah receptor is followed by AhR transport to the nucleus, dimerization with the aryl hydrocarbon nuclear translocator (ARNT), and transcription of a potentially large number of genes containing AhR complex-binding sequences in their promoter regions. Genes encoding cytochrome P450s(CYPs) enzymes are regarded as AhR-regulated genes. Induction of cytochrome P1A1 mRNA is a sensitive marker of AhR—ligand interaction. Our result demonstrates that tryptanthrin derivative DQ181 can inhibit TCDD-induced cytochrome P1A1 mRNA expression regarding to blocking or stablizing AhR-Hsp90 complex followed by inhibition of translocation from cytosol to nuclear. It may interfere with cytochrome P450 1A1-related carcinogenesis.

Chan, Hoi Ling.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2008.
Includes bibliographical references (leaves 206-220).
Abstracts in English and Chinese.
ACKNOWLEDGEMENTS --- p.i
ABBREVIATIONS --- p.ii
ABSTRACT --- p.viii
撮要 --- p.xii
PUBLICATIONS --- p.xiv
TABLE OF CONTENTS --- p.xv
Chapter CHAPTER 1: --- GENERAL INTRODUCTION
Chapter 1.1 --- Hematopoiesis & Leukemia --- p.1
Chapter 1.1.1 --- An Overview on Hematopoiesis Development --- p.1
Chapter 1.1.2 --- Leukemia --- p.6
Chapter 1.1.2.1 --- General Symptoms of Leukemia --- p.7
Chapter 1.1.2.2 --- Classification of Leukemia --- p.8
Chapter 1.1.2.3 --- Conventional Treatment against Leukemia --- p.15
Chapter 1.1.2.4 --- Novel Approaches --- p.19
Chapter 1.2 --- The Chinese Medicinal Herb-Banlangen (板藍根） --- p.24
Chapter 1.2.1 --- An Overview on Natural Indigo Compounds Derived from Banlangen --- p.24
Chapter 1.2.2 --- Tryptanthrin --- p.29
Chapter 1.2.2.1 --- Anti-bacterial Activity of Tryptanthrin --- p.29
Chapter 1.2.2.2 --- Anti-tumor Activity of Tryptanthrin --- p.31
Chapter 1.2.2.3 --- Anti-inflammatory Activity of Tryptanthrin --- p.33
Chapter 1.2.2.4 --- Cutting Edges of Tryptanthrin as a Drug --- p.34
Chapter 1.2.2.5 --- Metabolism of Tryptanthrin --- p.35
Chapter 1.3 --- Aims and Scopes of This Investigation --- p.37
Chapter CHAPTER 2: --- MATERIALS AND METHODS
Chapter 2.1 --- Materials --- p.39
Chapter 2.1.1 --- Animals --- p.39
Chapter 2.1.2 --- Cell Lines --- p.39
Chapter 2.1.3 --- "Cell Culture Medium, Buffers and Other Reagents" --- p.41
Chapter 2.1.4 --- Reagents for 3H-Thymidine Incorporation Assay --- p.45
Chapter 2.1.5 --- Reagents and Buffers for Flow Cytometry --- p.46
Chapter 2.1.6 --- Reagents for DNA Extraction --- p.49
Chapter 2.1.7 --- Reagents for Measuring Caspase Activity --- p.50
Chapter 2.1.8 --- Reagents for Total RNA Isolation --- p.53
Chapter 2.1.9 --- Reagents and Buffers for Reversed Transcription-PCR --- p.54
Chapter 2.1.10 --- Reagents and Buffers for Real Time-PCR --- p.59
Chapter 2.1.11 --- Reagents and Buffers for Gel Electrophoresis of Nucleic Acids --- p.59
Chapter 2.1.12 --- "Reagents, Buffers and Materials for Western Blot Analysis" --- p.61
Chapter 2.2 --- Methods --- p.70
Chapter 2.2.1 --- Culture of the Tumor Cell Lines --- p.70
Chapter 2.2.2 --- "Isolation, Preparation and Culture of Mouse Peritoneal Macrophages" --- p.70
Chapter 2.2.3 --- Determination of Cell Viability --- p.71
Chapter 2.2.4 --- Determination of Cell Proliferation by [3H]-TdR Incorporation Assay --- p.72
Chapter 2.2.5 --- Determination of Anti-leukemia Activity In Vivo --- p.73
Chapter 2.2.6 --- Analysis of Cell Cycle Profile/DNA Content by Flow Cytometry --- p.74
Chapter 2.2.7 --- Measurement of Apoptosis --- p.75
Chapter 2.2.8 --- Determination of the Mitochondrial Membrane Potential --- p.77
Chapter 2.2.9 --- Measurement of Caspase Activity --- p.78
Chapter 2.2.10 --- Study of Intracellular Accumulation of Reactive Oxygen Species --- p.79
Chapter 2.2.11 --- Gene Expression Study --- p.80
Chapter 2.2.12 --- Protein Expression Study --- p.83
Chapter 2.2.13 --- Measurement of Cell Differentiation --- p.87
Chapter CHAPTER 3: --- STUDIES ON THE ANTI-PROLIFERATIVE EFFECT OF TRYPTANTHRIN AND INDIRUBIN-3'-OXIME ON MYELOID LEUKEMIA CELLS
Chapter 3.1 --- Introduction --- p.90
Chapter 3.2 --- Results --- p.94
Chapter 3.2.1 --- Effects of Indirubin-3'-oxime and Tryptanthrin on the Proliferation of Myeloid Leukemia Cell Lines of Human and Murine Origins In Vitro --- p.94
Chapter 3.2.2 --- Kinetic and Reversibility Studies of the Anti-proliferative Effect of Tryptanthrin on Murine Myelomonocytic Leukemia WEHI-3B JCS Cells In Vitro --- p.108
Chapter 3.2.3 --- Cytotoxic Effect of Tryptanthrin on Murine Myelomonocytic Leukemia WEHI-3B JCS Cells In Vitro --- p.113
Chapter 3.2.4 --- Cytotoxicity of Tryptanthrin on Non-Cancer Cell Line and Primary Myeloid Cells In Vitro --- p.115
Chapter 3.2.5 --- Effects of Tryptanthrin on the Cell Cycle Profile of the Murine Myelomonocytic Leukemia WEHI-3B JCS Cells In Vitro --- p.118
Chapter 3.2.6 --- Effects of Tryptanthrin on the Expression of Cell Cycle Related Genes in Murine Myelomonocytic Leukemia WEHI-3B JCS Cells In Vitro --- p.123
Chapter 3.2.7 --- Expression of CDK-inhibitors in Tryptanthrin-treated Murine Myeloid Leukemia WEHI-3B JCS Cells --- p.126
Chapter 3.2.8 --- Effects of Tryptanthrin on the In Vivo Tumorigenicity of the Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.128
Chapter 3.2.9 --- In Vivo Anti-tumor Effect of Tryptanthrin on Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.130
Chapter 3.3 --- Discussion --- p.132
Chapter CHAPTER 4: --- STUDIES ON THE APOPTOSIS-INDUCING EFFECT OF TRYPTANTHRIN ON MURINE MYELOMONOCYTIC LEUKEMIA WEHI-3B JCS CELLS
Chapter 4.1 --- Introduction --- p.139
Chapter 4.2 --- Results --- p.143
Chapter 4.2.1 --- Induction of DNA Fragmentation by Tryptanthrin in the Murine Myelomonocytic Leukemia WEHI-3B Cells In Vitro --- p.143
Chapter 4.2.2 --- Induction of Phosphatidylserine Externalization by Tryptanthrin in Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.145
Chapter 4.2.3 --- Change of Mitochondrial Membrane Potential of Tryptanthrin- treated Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.147
Chapter 4.2.4 --- Induction of Caspase Activity in Tryptanthrin-treated Murine Myelomonocytic Leukemia WEHI-3B JCS cells --- p.150
Chapter 4.2.5 --- Induction of Reactive Oxygen Species in Tryptanthrin-treated Murine Myelomonocytic Leukemia WEHI-3B JCS cells --- p.155
Chapter 4.2.6 --- Expression of Bcl-2 Family Proteins in the Tryptanthrin-treated Murine Myelomonocytic Leukemia WEHI-3B JCS cells --- p.160
Chapter 4.2.7 --- Effects of Tryptanthrin on the mRNA Expression of Bcl-2 Family Proteins in Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.163
Chapter 4.2.8 --- Expression of Fas and Fas Ligand Proteins in Tryptanthrin-treated Murine Myelomonocytic Leukemia WEHI-3B JCS cells --- p.167
Chapter 4.2.9 --- Expression of Pro-Apoptotic Protein in Tryptanthrin- treated Murine Myelomonocytic Leukemia WEHI-3B JCS cells --- p.170
Chapter 4.2 --- Discussion --- p.173
Chapter CHAPTER 5: --- STUDIES ON THE DIFFERENTIATION-INDUCING ABILITY OF TRYPTANTHRIN ON MURINE MYELOMONOCYTIC LEUKEMIA WEHI-3B JCS CELLS
Chapter 5.1 --- Introduction --- p.184
Chapter 5.2 --- Results --- p.186
Chapter 5.2.1 --- Morphological Studies on Tryptanthrin-treated Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.186
Chapter 5.2.2 --- Effects of Tryptanthrin on the Cell Size and Granularity of the Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.189
Chapter 5.2.3 --- Effects of Tryptanthrin on Induction of NBT-reducing Activity in the Murine Myelomonocytic Leukemia WEHI-3B JCS Cells --- p.191
Chapter 5.3 --- Discussion --- p.195
Chapter CHAPTER 6: --- CONCLUSIONS AND FUTURE PERSPECTIVES --- p.198
REFERENCES --- p.206

碩士
國立臺灣大學
藥學研究所
97
Multidrug resistance (MDR), the resistance of tumor cells to anticancer agents, remains a major cause of treatment failure for cancer patients. MDR usually occurs with alteration of function and expression of some proteins and enzymes, for example P-gp (P-glycoprotein), MRP (multidrug resistance-related protein), topoisomerase and glutathione. Recently, the genes which show differential expressions in MCF-7/WT and its doxorubicin-resistant counterpart MCF-7/ADR include ER-α (estrogen receptor α), ER-β (estrogen receptor β), PR (progesterone receptor), VEGF（vascular endothelial growth factor）, HIF-1α ( hypoxia-inducible factor-1α ) , FoxO1（forkhead box-containing protein，O subfamily）, C/EBP β（CCAAT/enhancer-binding protein β）, CtBP1(C-terminal binding protein 1), dicer 1, argonaute 2, PIM-1 and PKc α (protein kinase c α). Our lab previously demonstrated that tryptanthrin could reverse the resistance to doxorubicin in MCF-7/ADR. In order to extensively understand the mechanisms of multidrug resistance, MCF-7/WT and MCF-7/ADR were treated with trptanthrin to examine the changes in expression of the above genes in this study, using RT-PCR, realtime-PCR and Western blot. Results show that tryptanthrin suppresses the expression of nuclear receptor genes in MCF-7/WT. The expression of ER-α is 50％ down. Furthermore, the binding of SP1 family proteins to ER-α promoter site IEF-1 decreases upon tryptanthrin treatment. In mRNA level, tryptanthrin inhibits the expression of PR prior to the expression of ER-α. As PR is downstream protein of ER-α, it seems that tryptanthrin acts on PR and ER-α via different pathways. When ER-α expression was knockdowned by siRNA in MCF-7/WT, the expression of MDR1 gene did not induced, suggesting the decrease in ER-α was not related to MDR1 gene expression in MCF-7/ADR.

碩士
國立中興大學
食品暨應用生物科技學系所
99
Hepatocellular carcinoma is a common tumor in Asia and Africa area. Tryptanthrin is a weakly basic alkaloid and has been reported to have various functions, such as anti-microorganisms, anti-parasites, immunomodulatory, anti-inflammatory and anti-tumor activity in vitro. In this study, we examined the efficacy of tryptanthrin in suppression hepatoma growth and further investigated the mechanism by which tryptanthrin alter tumor cell growth. Tryptanthrin significantly inhibited human hepatoma cell proliferation in vitro. However, our data showed that tryptanthrin did not alter expression or activity of caspase proteins, which was different from previous studies on this compound. Tryptanthrin increased intracellular reactive oxygen species and decreased the expression of growth-related proteins. Furthermore, the levels of apoptosis-related protein in the cytoplasmic and nuclear fractions were significantly increased by tryptanthrin treatment. Fluorescence microscope observation further discovered the nuclear translocation of apoptosis-related proteins and their nuclear condensation in tryptanthrin-treated cells. We suggest that tryptanthrin enhanced reactive oxygen species level that led to loss of mitochondrial potential in human hepatoma cells, followed by the activation of apoptotic protein release. The in vivo study subsequently showed that tryptanthrin supplementation inhibited tumor growth in BALB/c nu/nu athymic mice with human hepatoma cell xenograft. Tryptanthrin supplementation increased the number of apoptosis-related protein cells in tumors. The present study suggested that tryptanthrin may have anti-tumor potential in humans.

碩士
國立臺灣大學
藥學研究所
88
The resistance of tumor cells to anticancer agents remains a major cause of treatment failure for cancer patients. Agents as adjuvants to overcome MDR become a new trend in chemotherapy. We have evaluated the tryptanthrin derivatives DQ150 and EY083 for their reversing activity against P-glycoprotein-(P-gp) and MRP-mediated MDR in breast cancer cell lines MCF7, adriamycin-resistant MCF7/adr and etoposide-resistant MCF7/vp. Using MTT assay, 10-6M of DQ150 and EY083 had a 6-fold and 2-fold decrease in adriamycin IC50, respectively, in MCF7/adr. At mRNA level, DQ150 is more efficient than EY083 to diminish mdr1 (coding for P-gp, a membrane drug efflux pump) and glutathione S-transferase π (a drug detoxification enzyme) overexpression. Nevertheless, a large amount reduction of P-gp expression was observed using western blotting when MCF7/adr cells was treated with EY083 at 10-6M. DQ150 inhibits topoisomerase IIα and β completely, whereas EY083 partially inhibits topo IIα and does not inhibit topo IIβ at all. The compounds DQ150 and EY083 do not influence the mdr1 genomic DNA amplification. On the other hand, DQ150 and EY083 suppress the mdr1 gene at transcriptional level regarding to the influence on the mdr1 promoter regulation by AP-1 and p53. AP-1-DNA interaction was affected by the treatment with DQ150 and EY083 through the mobility shift assay. The amount of p53 decreased significantly when MCF7 were treated with DQ150 and EY083. Taken together, DQ150 and EY083 are likely to reverse P-glycoprotein, GSTπ and topoisomerase II-mediated MDR phenotype and may be as potential anticancer adjuvants in the future. Interestingly, in the MCF7/vp presenting MRP-mediated MDR, 10-6M EY083, but not DQ150, decreased etoposide IC50 15-fold. At mRNA level, EY083 diminished MRP overexpression. The differential inhibition of MRP mRNA expression between DQ150 and EY083 needs future study to unveil the correlation between P-gp- and MRP-mediated MDR.

碩士
國立臺灣大學
藥學研究所
89
Chemotherapy is a common and effective treatment for tumors. However, the resistance of tumor cells to anticancer agents remains a major cause of treatment failure in cancer patients. Increased expression in tumor cells of plasma membrane proteins such as the P-glycoprotein (P-gp) or the multidrug resistance-associated protein 1 (MRP1) is often associated with such multidrug resistance (MDR) phenotype. P-glycoprotein and MRP1 both belong to membrane transport proteins of the large ATP-binding cassette (ABC) superfamily but share less than 20% amino acid identity. We have evaluated the tryptanthrin derivatives DQ150 and EY083 for their reversing activity against P-gp and MRP-mediated MDR in breast cancer cell lines MCF-7 and its counter parts, adriamycin-resistant MCF-7 (MCF-7/adr) and etoposide-resistant MCF-7 (MCF-7/vp). Using RT-PCR assay, 10-6M DQ150 is more efficient than 10-6M EY083 to decrease MDR1, glutathione S-transferase π (a drug detoxification enzyme) and MRP1 mRNA overexpression. When MCF-7/adr cells were treated with DQ150 at 10-6M for 5 days, we observed a large amount of reduction of P-gp and GSTπ protein in parallel with decreases in mRNA. In MCF-7/vp, MRP1 protein decreases when treated with 10-6M DQ150. Many studies have provided evidence implicating complex formation for transcriptional regulation of the MDR1 and MRP1 gene promoters in human cancer cells. In addition, wild type p53 can modulate promoter activity of the human MDR1 and MRP1 genes. In MCF-7/adr cells, AP-1 and SP-1, interacting with MDR1 gene promoter, were affected by EY083 at 10-6M through the gel mobility shift assay, while it was not observed when treated with DQ150. However, DQ150 enhanced the NF-κB/p65 and c-Fos transcription factors interacting with the negatively regulatory CAAT region of the MDR1 gene promoter in MCF-7/adr. On the other hand, DQ150 is more efficient than EY083 in the interfering with the interaction of SP-1 and MRP1 gene promoter in MCF-7/vp. The amount of mutant p53 decreased significantly when MCF-7/adr and MCF-7/vp were treated with DQ150 and EY083 at 10-6M. Take together, we conclude that different mechanisms may be involved in the inhibition of MDR1 expression by DQ150 and EY083, while these two compounds inhibit MRP1 expression through similar pathways

碩士
國立臺灣大學
植物病理與微生物學研究所
106
This study aims to identify bioactive compounds that exert novel antifungal activity alone or exhibit synergistic effect with an existing antifungal agent against human fungal pathogens Cryptococcus and Candida. We screened several compound libraries including natural products, agricultural fungicides and FDA-approved drugs in order to identify compounds that exert antifungal activity. Among selected compounds, tryptanthrin secreted from Nocardiopsis alba, an actinobacterium existed in the intestine of honeybee, was chosen for further characterization because of its potent inhibition activity against Cryptococcus species with the minimal inhibition concentration (MIC) of 2 ug/mL for C. neoformans and 4 ug/mL for C. gattii. We further found that tryptanthrin showed synergistic effect with FK506, an immunosuppressant, based on broth dilution and checkerboard assays. Tryptanthrin inhibits the growth of Cryptococcus cells in a dose-dependent manner and shows fungistatic activity instead of fungicidal. We also found that tryptanthrin is more effective at 37 ºC compared with to 30 ºC or 25 ºC. Meanwhile, tryptanthrin demonstrated antifungal activity against two clinical azole-resistant C. neoformans isolates, T1 and 89-610. In order to identify potential targets or pathways that tryptanthrin involves in, we screened the Cryptococcus deletion mutant library by drug susceptibility test. Forty-nine deletion mutants were found to be more susceptible or resistant than that of the wild-type, and some of these mutants were involved in in cell cycle regulation. Fluorescence-activated cell sorting and gene expression quantification results support that cell cycle regulation in C. neoformans may be linked to tryptanthrin. In summary, the natural product tryptanthrin shows novel antifungal activity alone or in combination with FK506, leading possible therapeutic strategies for cryptococcosis caused by Cryptococcus species, especially the azole-resistant isolates.