bluuebunny/crossref_metadata_2025 huggingface dataset:
A Theoretical Study of Correlation between Hydrogen‐Bond Stability and J‐Coupling through a Hydrogen Bond
Authors: Kawahara Shun‐ichi , Kojima Chojiro , Taira Kazunari , Uchimaru Tadafumi
Published: June 2004

trans‐Hydrogen‐bond hyperfine splitting via magnetic interaction, which is observed as J‐coupling in NMR experiments, was theoretically studied. trans‐Hydrogen‐bond hyperfine splitting should be closely related to the orbital interaction between the lone‐pair orbital of the H‐bond acceptor and the antibond orbital of the H‐bond donor. A linear relationship was observed between magnetic interaction hyperfine splitting through a H‐bond and the H‐bond strength. The relationship was dependent on the type of the nucleus forming the H‐bond; linear correlation was observed in NH⋅⋅⋅O/N type or OH⋅⋅⋅N type H‐bonded complexes, but not in OH⋅⋅⋅O type H‐bonded complexes.
Etorphine‐Related Ferrocenyl‐Substituted Morphinan Alkaloids
Authors: Laus Gerhard , Schütz Johannes , Schottenberger Herwig , Andre Max , Wurst Klaus , Spetea Mariana , Ongania Karl‐Hans , Müller Adrian G. , Schmidhammer Helmut
Published: June 2004

The two diastereoisomeric ferrocenyl‐substituted orvinols 2 and 3 were prepared. The modified alkaloids are still able to interact with opioid receptors (see Table). The ferrocene moiety allows highly selective and sensitive electrochemical detection. The X‐ray crystal structure of the major isomer 2 was determined. The combination of a metallocene and a morphinan alkaloid holds promise for useful antitumor activity.
The Synthesis, Characterisation, and Reactivity of Some Polydentate Phosphinoamine Ligands with Benzene‐1,3‐diyl and Pyridine‐2,6‐diyl Backbones
Authors: Biricik Nermin , Fei Zhaofu , Scopelliti Rosario , Dyson Paul J.
Published: June 2004

The polydentate phosphinoamines 1,3‐{(Ph2P)2N}2C6H4 and 2,6‐{(Ph2P)2N}2C5H3N have been prepared in a single step from the reaction of the amines 1,3‐(NH2)2C6H4 or 2,6‐(NH2)2C5H3N with Ph2PCl in presence of Et3N (1 : 4 : 4 molar ratio) in CH2Cl2. Reaction of 1,3‐{(Ph2P)2N}2C6H4 or 2,6‐{(Ph2P)2N}2C5H3N with elemental sulfur or selenium in CH2Cl2 affords the corresponding tetrasulfide or tetraselenide, respectively, in good yield. The complexes [1,3‐{Mo(CO)4(Ph2P)2N}2(C6H4)] and [2,6‐{Mo(CO)4(Ph2P)2N}2(C5H3N)] were prepared from the reaction of these phosphinoamines with [Mo(CO)4(nbd)] (nbd=norbornadiene) in toluene, and the structure of the latter complex has been determined by single‐crystal X‐ray diffraction analysis.
Challenges in Modelling and Optimization of Stability Constants in the Study of Metal Complexes with Monoprotonated Ligands. Part II
Authors: Machado Carina M. M. , Cukrowski Ignacy , Soares Helena M. V. M.
Published: June 2004

The influence of 2‐hydroxy‐3‐[(2‐hydroxy‐1,1‐dimethylethyl)amino]propane‐1‐sulfonic acid (AMPSO=HL) on systems containing copper(II) was studied by glass‐electrode potentiometry (GEP) and direct‐current polarography (DCP), at fixed total‐ligand‐to‐total‐metal‐concentration ratios and various pH values (25°, 0.1M KNO3 medium). The predicted model ([CuL]+, [CuL(OH)], [CuL2], [CuL2(OH)]−, [CuL2(OH)2]2−, and [CuL3]−) and the overall stability constants for species found were obtained by combining results from both electrochemical techniques. The last five complexes are reported for the first time. For the species [CuL]+, [CuL2], [CuL3]−, and [CuL2(OH)2]2−, it was possible to determine stability constants with reasonable certainty and their values, as log β, were found to be 4.62±0.04, 9.5±0.1, 13.4±0.1, and 21.2±0.1, respectively. For the species [CuL(OH)] and [CuL2(OH)]−, stability constants 11.7±0.2 and 15.6±0.2, respectively, are presented as indicative values. It was demonstrated that AMPSO buffer may decrease the Cu2+ concentration by ten orders of magnitude by forming complexes with Cu2+. For the first time, the correction in DCP waves for the adsorption of the ligand and quasi‐reversibility of the metal allowed to determine stability‐constant values that are in good agreement with the values obtained by GEP. The importance of graphic analysis of data and significance of employing two analytical techniques was demonstrated; neither GEP nor DCP would be able to provide the correct M/L/OH− model and reliable stability constants when used independently.
A New Glycoside and a Novel‐Type Diterpene from Hemerocallis fulva (L.) L.
Authors: Yang Zhong‐duo , Chen Hua , Li Yuan‐chao
Published: June 2004

The CHCl3 extract of dried roots of Hemerocallis fulva (L.) L. afforded a novel diterpene named hemerocallal A (1), which is the second reported naturally occurring diterpene with a trans‐bicyclo[5.1.0]octane system. The BuOH extract afforded a new glycoside named hemerocalloside (2). Their structures were established on the basis of spectroscopic and chemical studies.
A Concise Synthesis of 2‐Amino‐1,2,3,4‐tetrahydronaphthalene‐6,7‐diol (‘6,7‐ADTN’) from Naphthalene‐2,3‐diol
Authors: Göksu Süleyman , Kazaz Cavit , Sütbeyaz Yaşar , Seçen Hasan
Published: June 2004

2‐Amino‐1,2,3,4‐tetrahydronaphthalene‐6,7‐diol (2; 6,7‐ADTN) was synthesized starting from naphthalene‐2,3‐diol in seven steps and with an overall yield of 44%. Methylation of naphthalene‐2,3‐diol with dimethyl sulfate, followed by FriedelCrafts acylation with AcCl, gave 2‐acetyl‐6,7‐dimethoxynaphthalene. 2‐Acetyl‐6,7‐dimethoxynaphthalene was converted to 6,7‐dimethoxynaphthalene‐2‐carboxylic acid by a haloform reaction. Birch reduction of the carboxylic acid with 4 mol‐equiv. of Na in liquid ammonia afforded 1,2,3,4‐tetrahydro‐6,7‐dimethoxynaphthalene‐2‐carboxylic acid, from which 2 was obtained by a Curtius reaction, followed by hydrogenolysis and demethylation.
New Synthesis of Natural Carotene Isorenieratene (ϕ,ϕ‐Carotene) and its 3,3′‐Dimethoxy Analogue
Authors: Valla Alain R. , Cartier Dominique L. , Valla Benoist G. , Le Guillou Régis Y. , Andriamialisoa Zo R. , Labia Roger , Breithaupt Dietmar E. , Savy Stéphanie M. , Binet Adrien , Dufossé Laurent H.
Published: June 2004

The main pigments of Brevibacterium linens are the aromatic carotenoids 3,3′‐dihydroxyisorenieratene (φ,φ‐carotene‐3,3′‐diol), the corresponding monohydroxy compound, and the hydrocarbon isorenieratene. We report herein new syntheses of isorenieratene (ϕ,ϕ‐carotene) and its xanthophyll analogue, 3,3′‐dimethoxy‐ϕ,ϕ‐carotene, which may be considered a protected form of the natural xanthophyll, 3,3′‐dihydroxy‐ϕ,ϕ‐carotene.
Antitumor Sesquiterpenes from Euonymus nanoides
Authors: Wang Hong , Tian Xuan , Pan Yuanjiang
Published: June 2004

The isolation, structure elucidation, and antitumor activity of four new sesquiterpene polyol esters, i.e., of 6α,13‐bis(acetyloxy)‐9β‐(cinnamoyloxy)‐1β‐(furan‐3‐ylcarbonyl)oxy]‐4α‐hydroxy‐β‐dihydroagarofuran (1), 13‐(acetyloxy)‐9β‐(benzoyloxy)‐4α‐hydroxy‐1β,6α‐bis[(2‐methylbutanoyl)oxy]‐β‐dihydroagarofuran (2), 1β,6α,13‐ tri(acetyloxy)‐9β‐(cinnamoyloxy)‐4α‐hydroxy‐β‐dihydroagarofuran (3), and 6α,13‐bis(acetyloxy)‐9β‐(benzoyloxy)‐4α‐hydroxy‐1β‐[(2‐methylbutanoyl)oxy]‐β‐dihydroagarofuran (4), and of five known sesquiterpene polyol esters 5–9 from the seed oil of Euonymus nanoides Loes. are reported (β‐dihydroagarofuran=octahydro‐2,2,5a,9‐tetramethyl‐2H‐3,9a‐methano‐1‐benzoxepin).
Synthesis of N‐[(tert‐Butoxy)carbonyl]‐3‐(9,10‐dihydro‐9‐oxoacridin‐2‐yl)‐L‐alanine, a New Fluorescent Amino Acid Derivative
Authors: Szymańska Aneta , Wegner Katarzyna , Łankiewicz Leszek
Published: June 2004

A simple synthesis of a new, highly fluorescent amino acid and of its protected derivative useful in peptide studies is described. The obtained derivative, N‐[(tert‐butoxy)carbonyl]‐3‐(9,10‐dihydro‐9‐oxoacridin‐2‐yl)‐L‐alanine (6), shows intense long‐wave absorption (above 360 nm) and emission (above 400 nm). The quantum yield of fluorescence of the investigated compound is very high, so it can serve as a sensitive analytical probe useful, e.g., in analysis of peptide conformations.
Controlled Synthesis of Substituted Benzobasketene Derivatives
Authors: Aydinli Betül , Çelik Murat , Gültekin M. Serdar , Uzun Orhan , Balcı Metin
Published: June 2004

The addition of benzyne to trans‐7,8‐dibromobicyclo[4.2.0]octa‐2,4‐diene (6) led to the formation of dibromide 7. The dehydrobromination of 7 followed by replacement of the Br‐atom with a CN substituent gave 9. Photolysis of 9 in acetone at 254 nm yielded the desired monosubstituted benzobasketene derivative 10. Bromination of monobromide 8 followed by dehydrobromination furnished the symmetrically substituted dibromo compound 15. Further bromination of 7 followed by dehydrobromination resulted in the formation of the dibromides 20 and 21. Substitution of the Br‐atoms in 15, 20, and 21 with CN substituents and photolysis of the formed dicarbonitriles 16, 23, and 24 gave the target benzobasketene‐dicarbonitriles 17, 25, and 26, respectively.
Transformation of Azadiradione to Nimbocinol and 17β‐Hydroxynimbocinol, and StructurePesticidal‐Activity Relationship of Triterpenoids isolated from Azadirachta indica A. Juss. (Neem)
Authors: Siddiqui Bina S. , Rasheed Munawwer , Faizi Shaheen , Firdous  , Ali S. Tariq , Tariq Rajput M. , Naqvi Syed Naeem‐ul‐Hassan
Published: June 2004

During studies on the structurepesticidal‐activity relationship of Azadirachta indica constituents, azadiradione (1) was treated with methanolic K2CO3 to obtain 7‐deacetyl derivative nimbocinol (2). Unexpectedly, 17β‐hydroxynimbocinol (3), reported earlier as a natural product, was also formed. The structurepesticidal‐activity relationship of triterpenoids 1–16 against Anopheles stephensi Liston is described towards understanding the active functionalities responsible for the pesticidal activity of triterpenoids having apoeuphane(apotirucallane) and gedunin skeleta. The pesticidal activities of triterpenoids 2–8 are reported for the first time.
Isoflavonoid Glycosides from the Rhizomes of Iris germanica
Authors: Atta‐ur‐Rahman  , Nasim Shama , Baig Irfan , Orhan Ilkay , Sener Bilge , Ayanoglu Filiz , Choudhary M. Iqbal
Published: June 2004

Five new di‐ and triglycosides, irigenin 7‐[O‐β‐D‐glucopyranosyl‐(1→6)‐β‐D‐glucopyranoside] (1), 6‐hydroxygenistein 4′‐[O‐β‐D‐glucopyranosyl‐(1→6)‐β‐D‐glucopyranoside] (2), nigricin 4′‐[O‐β‐D‐glucopyanosyl‐(1→6)‐β‐D‐glucopyranoside] (3), nigricin 4′‐[O‐β‐D‐glucopyanosyl‐(1→2)‐O‐[α‐L‐rhamnopyranosyl‐(1→6)]‐β‐D‐glucopyranoside] (4), and 7‐{4′‐{[2″‐O‐(4′′′′‐acetyl‐2′′′′‐methoxyphenyl)‐β‐D‐glucopyranosyl]oxy}‐3′‐(β‐D‐glucopyranosyloxy)phenyl]‐9‐methoxy‐8H‐1,3‐dioxolo[4,5‐g]‐[1 benzopyran‐8‐one‐] (5), along with a known compound, nigricin 4′‐(β‐D‐glucopyranoside) (6), were isolated from the rhizomes of Iris germanica. The structures of these compounds were established by spectroscopic methods, including 2D NMR spectroscopic techniques.
Photophysical and Photochemical Studies of Pyridoxamine
Authors: Bueno Claudio , Encinas María Victoria
Published: June 2004

The absorption and fluorescence emission of pyridoxamine were studied as function of pH and solvent properties. In the ground state, pyridoxamine exhibits different protonated forms in the range of pH 1.5–12. Fluorescence studies showed that the same species exist at the lowest singlet excited state but at different pH ranges. The phenol group is by ca. 8 units more acidic in the excited state than in the ground state. On the other hand, the pyridine N‐atom is slightly more basic in the lowest excited state than in the ground state. Excitation spectra and emission decays in the pH range of 8–10 indicate the protonation of the pyridine N‐atom by proton transfer from the amine group, in the ground and singlet excited states. Spectroscopic studies in different solvents showed that pyridoxamine in the ground or excited states exhibits intramolecular proton transfer from the pyridine N‐atom to the phenol group, which is more favorable in solvents of low hydrogen‐bonding capacity. The cationic form with the protonated phenolic group, which emits at shorter wavelength, is the dominant species in nonprotic solvents, but, in strong proton‐donor solvents, both forms exist. The fluorescence spectra of these species exhibit blue shift in protic solvents. These shifts are well‐correlated with the polarity and the H‐donor ability of the solvent.
Cyclopeptides and Amides from Pseudostellaria heterophylla (Caryophyllaceae)
Authors: Yang Ya‐bin , Tan Ning‐hua , Zhang Fei , Lu Ya‐qing , He Min , Zhou Jun
Published: June 2004

From the roots of Pseudostellaria heterophylla, three cyclopeptides and three amides were isolated, besides heterophyllin A and B. Their structures were determined as cyclo (Ala‐Gly‐Pro‐Val‐Tyr‐) (heterophyllin J; 1), cyclo (Ala‐Gly‐Pro‐Tyr‐Leu‐) (pseudostellarin A; 2), cyclo (Gly‐Gly‐Gly‐Pro‐Pro‐Phe‐Gly‐Ile‐) (pseudostellarin B; 3), methyl γ‐hydroxypyroglutamate (4), methyl pyroglutamate (5), and pyroglutamic acid (6) on the basis of spectral data, especially 2D‐NMR data. Among them, compounds 1 and 4 are new compounds.
Isolation, Structure, and HIV‐1 Integrase Inhibitory Activity of Xanthoviridicatin E and F, Two Novel Fungal Metabolites Produced by Penicillium chrysogenum
Authors: Singh Sheo B. , Zink Deborah L. , Guan Ziqiang , Collado Javier , Pelaez Fernando , Felock Peter J. , Hazuda Daria J.
Published: June 2004

HIV‐1 Integrase is a critical enzyme for replication of HIV, and its inhibition is one of the most promising new drug targets for anti‐retroviral therapy with potentially significant advantages over existing therapies. Xanthoviridicatins E (1) and F (2) are two novel polyketide natural products that were isolated from a fermentation broth of an endophytic strain of Penicillium chrysogenum isolated from the living leaves collected in Peru. These compounds are new members of the unsymmetrical xanthoviridicatin family represented by the broader xanthomegnin family. Xanthoviridicatins E and F inhibited the cleavage reaction of HIV‐1 integrase with an IC50 of 6 and 5 μM, respectively. The bioassay‐directed isolation, structure elucidation, and HIV‐1 inhibitory activity of these compounds are described.
Isolation and Structure Determination of New Jatrophane Diterpenoids from Euphorbia platyphyllos L.
Authors: Hohmann Judit , Forgo Peter , Csupor Dezsö , Schlosser Gitta
Published: June 2004

Three new, highly functionalized jatrophane diterpenes (1–3) have been isolated from the whole, dried plants of Euphorbia platyphyllos L., together with one known jatrophane polyester (4). The structures were established by UV/VIS spectroscopy, HR‐ESI‐MS, and advanced two‐dimensional NMR, including 1H‐NMR, JMOD, 1H,1H‐COSY, HMQC, and HMBC experiments. Stereochemical studies and conformational analyses were performed by means of NOESY experiments. Interestingly, compounds 1–4 do not represent a stereochemically uniform series because they differ in the orientations of the Me groups at C(2), C(6), and C(13). A similar observation was reported earlier for Euphorbia serrulata, whose diterpenes are related to the compounds obtained from E. platyphyllos. This chemical relationship is of taxonomic importance and supports the botanical similarity of the two species.
A New Dimeric Stilbenoid with a Five‐Membered Lactone Ring from Shorea hemsleyana
Authors: Ito Tetsuro , Tanaka Toshiyuki , Iinuma Munekazu , Nakaya Ken‐ichi , Takahasi Yoshikazu , Nakamura Hikaru , Naganawa Hiroshi , Riswan Soedarsono
Published: June 2004

From the stem bark of Shorea hemsleyana, a new dimeric stilbenoid with a five‐membered lactone ring, shorealactone (1) was isolated. The absolute configuration was determined by means of 2D NMR techniques and X‐ray crystal‐structure analysis of its 4‐bromobenzoyl derivative 1e by means of anomalous scattering of the Br‐atom.
Anionically Substituted 1,1′,1″‐Methylidynetris[1H‐pyrazole] Ligands for the Formation of Neutral Lanthanide Complexes in Water: Synthesis, Characterization, and Photophysical Properties
Authors: Charbonnière Loïc J. , Ziessel Raymond
Published: June 2004

The six‐step synthesis of the new podand‐type ligand 6,6′,6″‐[methylidenetri(1H‐pyrazole‐1,3‐diyl)]tris[pyridine‐2‐carboxylic acid] (LH3) is described. Reaction of LH3 with LnCl3 ⋅6 H2O (Ln=Eu, Gd, Tb) in MeOH resulted in the isolation of [LnL]⋅HCl complexes characterized by elemental analysis, mass and IR spectroscopy. Photophysical studies of the Eu and Tb complexes in aqueous solutions revealed the characteristic luminescence features of the metal atoms, indicative of an efficient ligand‐to‐metal energy‐transfer process. Determination of the luminescence quantum yields in H2O showed the Tb complex to be highly luminescent (ϕ=15%), while, for the Eu complex, the quantum efficiency was only 2%. Excited‐state‐lifetime measurements in H2O and D2O evidenced the presence of ca. three H2O molecules in the first coordination sphere of the complexes. Investigation of the Gd complex allowed the determination of the ligand‐centered triplet state and showed the ligand to be well suited for energy transfer to the metal. The luminescence properties of the complexes are described, and the properties of the ligand as a suitable complexation pocket is questioned.
Cyclotrimerization of Benzobarrelene: Synthesis of New Isomeric Barrelene Architectures
Authors: Daştan Arif , Fabris Fabrizio , De Lucchi Ottorino , Güney Murat , Balcı Metin
Published: June 2004

The cyclotrimerization reaction of benzobarrelene derivatives was investigated. Dibromobenzobarrelene 10 was converted to the bromostannyl derivative 11, which was used as the substrate of the cyclotrimerization reaction. Thus, reaction of 11, with copper(I) thiophene‐2‐carboxylate (CuTC) gave a mixture of the isomeric cyclotrimers 5 and 6 and the dimers 12 and 13, in addition to a trace of protodestannylated bromoalkene 14 (Scheme 2).
Self‐Assembly of Non‐Biological Polymeric Strands Undergoing Enforced Helical Self‐Organization
Authors: Schmitt Jean‐Louis , Lehn Jean‐Marie
Published: June 2004

The polycondensation of a dihydrazino‐pyrimidine (5 and 6) with a pyrimidine‐dicarbaldehyde (7 and 8b) provides an efficent access to helical polymeric strands based on the formation of hydrazone connections between the pyrimidine groups. The folding into a helical structure is enforced by the helicity codon defined by the (hydrazonepyrimidine) sequence. The polymers obtained have been characterized by mass spectrometry, indicating molecular weights up to ca. 12000 Da. Electronic spectra display specific absorption and emission features. These helical polymers present a core diameter of ca. 20 Å, a pitch of 3.5 Å, and, for a molecular weight around 9000 Da, a height of ca. 42 Å with 12 turns. The self‐assembled helical polymers obtained represent stable frameworks for the lateral attachment of functional residues in a helical disposition. Such entities may possess a range of novel chemical as well as biological properties.
Structure Elucidation of the First Inhibitors of Human Papillomavirus Type 11 E1E2 ProteinProtein Interaction
Authors: Yoakim Christiane , Goudreau Nathalie , McGibbon Graham A. , O'Meara Jeff , White Peter W. , Ogilvie William W.
Published: June 2004

A novel series of inhibitors of the HPV11 E1E2 proteinprotein interaction was identified. These inhibitors, which were discovered as a result of high‐throughput screening, feature an indandione system spiro‐fused onto an appropriately substituted tetrahydrofuran ring. Early stability studies indicated, surprisingly, that this particular series of compounds were readily converted, in binding assay buffer, to the corresponding carboxylates. NMR and mass spectrometry techniques were used to elucidate the structures of these products and the mechanism by which they are produced.
3β‐(Stearyloxy)olean‐12‐ene from Austroplenckia populnea: Structure Elucidation by 2D‐NMR and Quantitative 13C‐NMR Spectroscopy
Authors: Filho S. A. Vieira , Duarte L. P. , Silva G. D. F. , Howarth O. W. , Lula I. S.
Published: June 2004

3β‐(Stearyloxy)olean‐12‐ene was isolated from a hexane extract of Austroplenckia populnea Reiss (Celastraceae) leaves. The structure was solved by means of quantitative 13C‐NMR, HMBC, HMQC, COSY, NOESY, and NOE difference spectra. The mass spectrum showed an [M+1]+ ion peak at m/z 693, and the molecular formula C48H84O2 was confirmed by combustion analysis.
Microbial Transformation of Isolongifolen‐4‐one
Authors: Choudhary M. Iqbal , Musharraf Syed Ghulam , Khan Mahmud Tareq Hassan , Abdelrahman Doaa , Parvez Massod , Shaheen Farzana , Atta‐ur‐Rahman
Published: June 2004

The microbial transformation of (+)‐isolongifolen‐4‐one (4) by a number of fungi by means of a standard two‐stage fermentation technique afforded (7R)‐12‐hydroxyisolongifolen‐4‐one (5), (7S)‐13‐hydroxyisolongifolen‐4‐one (6), (11R)‐11‐hydroxyisolongifolen‐4‐one (7), (10R)‐10‐hydroxyisolongifolen‐4‐one (8), and (9R)‐9‐hydroxyisolongifolen‐4‐one (9) (Scheme). All five metabolites were found to be new, and metabolites 6 and 9 showed potent tyrosinase inhibitory activity (Table 1). The metabolites and their derivatives were characterized on the basis of spectroscopic and single‐crystal X‐ray‐diffraction techniques.
Comparative Study on the Reactivity of 6‐Haloimidazo[1,2‐a]pyridine Derivatives towards Negishi‐ and Stille‐Coupling Reactions
Authors: Hervet Maud , Théry Isabelle , Gueiffier Alain , Enguehard‐Gueiffier Cécile
Published: June 2004

The scope of the Suzuki‐cross‐coupling reaction of 6‐haloimidazo[1,2‐a]pyridines is dependent on the availability of the (hetero)arylboronic acids. Thus, with the aim to develop expanded applications of (hetero)arylations of imidazo[1,2‐a]pyridines, we investigated the Negishi‐ and Stille‐cross‐coupling reactions at the 6‐position. Remarkably, attempts to apply the Negishi‐cross‐coupling conditions to the organozinc derivative prepared from 6‐haloimidazo[1,2‐a]pyridine via a lithiumzinc exchange led to the 5‐phenyl compound 3 in 54% yield instead of the desired 6‐phenyl isomer (Scheme 1). In contrast, various commercially available halogenated five‐ or six‐membered‐ring heterocycles were efficiently coupled to the 6‐(trialkylstannyl)imidazo[1,2‐a]pyridine under Stille conditions (Table 2).
Micranthin C, a Novel 13(12→11)abeo‐Abietanoid from Isodon lophanthoids var. micranthus
Authors: Zhao Ai‐Hua , Li Sheng‐Hong , Zhao Qin‐Shi , Lin Zhong‐Wen , Sun Han‐Dong , Lu Yang , Zhang Li‐Li , Zheng Qi‐Tai
Published: June 2004

A novel 13(12→11)abeo‐abietane skeletal diterpenoid, micranthin C (1), was isolated from Isodon lophanthoids var. micranthus. Its structure was determined by various spectroscopic techniques and finally confirmed by single‐crystal X‐ray diffraction.
A Novel Oxime‐Derived Solid Support for the Synthesis of 3‐Phosphorylated Oligonucleotides
Authors: Langenegger Simon M. , Moesch Luzia , Natt François , Hall Jonathan , Häner Robert
Published: June 2004

Oligonucleotides containing terminal phosphate groups serve as useful intermediates for different applications in molecular and cell biology, as well as for diagnostic purposes. The chemical synthesis of these derivatives has been an important topic of oligonucleotide research. We report here a novel polystyrene‐based solid support bearing an α‐hydroxy oximate linker that allows the synthesis of 3′‐phosphorylated oligodeoxynucleotides as well as oligoribonucleotides in high quality. The formation of the phosphorylated oligonucleotides likely proceeds through an eliminative pathway with concurrent nitroso‐ene production.
Synthesis of C(2)‐Substituted manno‐Configured Tetrahydroimidazopyridines and Their Evaluation as Inhibitors of Snail β‐Mannosidase
Authors: Terinek Miroslav , Vasella Andrea
Published: June 2004

It was shown that retaining β‐glucosidases and galactosidases of families 1–3 feature a strong interaction between C(2)OH of the substrate and the catalytic nucleophile. An analogous interaction can hardly take place for retaining β‐mannosidases. A structureactivity comparison between the inhibition of the β‐glucosidase from Caldocellum saccharolyticum (family 1) and β‐glucosidase from sweet almonds by the gluco‐imidazoles 1–6, and the inhibition of snail β‐mannosidase by the corresponding manno‐imidazoles 8–13 does not show any significant difference, suggesting that also the mechanisms of action of these glycosidases do not differ significantly. For this comparison, we synthesized and tested the manno‐imidazoles 9–13, 28, 29, 32, 35, 40, 41, 43, 46, 47, and 50. Among these, the alkene 29 is the strongest known inhibitor of snail β‐mannosidase (Ki=6 nM, non‐competitive); the aniline 35 is the strongest competitive inhibitor (Ki=8 nM).
The Aldol Reaction of Allenolates with Aldehydes in the Presence of Magnesium Diiodide (MgI2) as Catalyst
Authors: Deng Guang‐Hui , Hu Hui , Wei Han‐Xun , Paré Paul W.
Published: June 2004

Stereoselective synthesis of (Z)‐α‐(hydroxyalkyl)‐β‐iodoacrylates (=(2Z)‐2‐(hydroxyalkyl)‐3‐iodoprop‐2‐enoates) was achieved in a one‐pot coupling reaction from methyl prop‐2‐ynoate, Me3SiI, and an alkanal under mild conditions with MgI2 as catalyst (→ 1–9; see Table and Scheme 1). Baylis‐Hillman β‐iodo adducts were generated in excellent yields with high (Z)‐selectivity. The conversion of methyl prop‐2‐ynoate to an active methyl 3‐iodo‐1‐[(trimethylsilyl)oxy]allenolate intermediate in situ followed by carbonyl addition is proposed as the reaction sequence (Schemes 1 and 2).
Solid‐Phase Synthesis of Dipeptide‐Conjugated Nucleosides and Their Interaction with RNA
Authors: Dong Guimin , Zhang Liangren , Zhang Lihe
Published: June 2004

Dipeptide‐conjugated nucleosides were efficiently synthesized from the intermediates of 3′‐amino‐3′‐deoxy‐nucleosides by using the solid‐phase synthetic strategy with HOBt/HBTU (1‐hydroxy‐1H‐benzotriazole/2‐(1H‐benzotriazol‐1‐yl)‐1,1,3,3‐tetramethyluronium hexafluoroborate) as the coupling reagents (Schemes 1–3). CD Spectra and thermal melting studies showed that the synthesized hydrophobic dipeptidethymidine and uridine derivatives 8a–8d, 13a–d, and 18 had a mild affinity with the polyA⋅polyU duplex and could induce the change of RNA conformation. The results also implied that the interaction of conjugates with RNA might be related to the sugar pucker conformation of the nucleoside.
Recombinant single‐chain antibody fusion construct targeting human melanoma cells and containing tumor necrosis factor
Authors: Liu Yuying , Cheung Lawrence H. , Marks John W. , Rosenblum Michael G.
Published: June 2004

Fusion constructs targeting tumor cells have significant potential applications against both solid tumors and hematologic malignancies. We developed a fusion construct of tumor necrosis factor (TNF) and a single‐chain antibody (scFvMEL) recognizing the gp240 antigen on human melanoma cells. The scFvMEL/TNF construct, like TNF itself, was found to exist in solution primarily as a trimer of 45 kDa monomers (trimeric molecular weight = 135 kDa). The fusion construct bound specifically to gp240 antigen‐positive but not to antigen‐negative cells. The TNF component of the construct was biologically active (specific activity = 1 × 107 U/mg) compared with free TNF (specific activity = 2.6 × 107 U/mg) and was more cytotoxic to antigen‐positive A375‐M melanoma cells (IC50 = 100 pM) than TNF alone (IC50 = 1,000 pM) and, additionally, was active against AAB‐527 melanoma cells (IC50 = 20 nM) resistant to TNF itself (IC50 > 1,000 nM). The augmented cytotoxicity was mediated by antibody‐specific binding to the cell surface. Both A375‐M and AAB‐527 cells were shown to express TNFR1 and TNFR2 on the cell surface. The TNF moiety of the fusion construct was efficiently delivered into cells in time‐dependent increase in cytosol as assessed by immunofluorescent staining of human melanoma cells. Radiolabeled scFvMEL/TNF localized effectively in human melanoma xenografts in nude (nu/nu) mice with a tumor:blood ratio of approximately 8 at 72 hr after administration. Our studies suggest that because of its unique biologic activity and low antigenic potential, scFvMEL/TNF makes an excellent cytotoxic protein for potential clinical treatment of human melanoma. © 2003 Wiley‐Liss, Inc.
Modification effects of GSTM1, GSTT1 and CYP2E1 polymorphisms on associations between raw salted food and incomplete intestinal metaplasia in a high‐risk area of stomach cancer
Authors: Chen Shu‐Yuan , Liu Tzeng‐Ying , Shun Chia‐Tung , Wu Ming‐Shiang , Lu Tsung‐Hsueh , Lin Jaw‐Town , Sheu Jin‐Chuan , Santella Regina M. , Chen Chien‐Jen
Published: June 2004

Incomplete intestinal metaplasia (IM) is a precursor of stomach cancer. To identify risk factors of incomplete IM, a 2‐stage survey was carried out in 1995 among 1,485 residents in Matzu, an area with highest mortality from stomach cancer in Taiwan. There were 312 study subjects including 174 men and 138 women sampled for the gastroendoscopic examination of IM. Information on personal and familial history of stomach cancer, cigarette smoking, alcohol consumption and intake frequency of various salted food items were obtained by personal interview based on a structured questionnaire. Blood samples were collected from each participant. Four biopsies per subject were taken from all subjects at gastroendoscopic examination to diagnose the status of IM pathologically. The Helicobacter pylori in biopsies was detected by the histomorphological or immunochemistry method, and antibodies against H. pylori in serum by the enzyme‐linked immunosorbent assay. Plasma level of selenium was determined by atomic absorption spectrometry, plasma level of retinol, α‐tocopherol, α‐carotene, and β‐carotene by high performance liquid chromatography, genotypes of glutathione S‐transferase (GST) M1 and T1 and cytochrome P450 (CYP) 2E1 by polymerase chain reaction. The significant association between history of stomach cancer among first‐degree relatives and incomplete IM was found (odds ratio [OR] = 2.50; 95% confidence interval [CI] = 1.15–5.43). There was no association between H. pylori infection and incomplete IM. Alcohol drinkers for >20 years had an elevated risk compared to non‐drinkers (OR = 3.34; 95% CI = 1.19–9.39). No associations between incomplete IM and plasma levels of selenium, retinol, α‐tocopherol, α‐carotene and β‐carotene were found. Salted food including salted meat, dehydrated salted vegetables and raw salted seafood consumed at ages of ≤15 and 16–30 years old was associated with an increased IM risk with OR ranging from 2–3. More striking associations between incomplete IM and salted food intake were observed among subjects with genotypes of GSTM1 null, GSTT1 non‐null and CYP2E1 c1/c1. Our study suggests the importance of gene–environment interaction on the development of incomplete IM. © 2003 Wiley‐Liss, Inc.
2‐methoxyestradiol induces caspase‐independent, mitochondria‐centered apoptosis in DS‐sarcoma cells
Authors: Lambert Christine , Apel Katrin , Biesalski Hans Konrad , Frank Juergen
Published: June 2004

The anti‐cancer potential of the natural estrogen metabolite 2‐methoxyestradiol is associated with microtubuli interaction, anti‐angiogenetic effects and inhibition of superoxide dismutase leading to apoptosis. The effectors of apoptotic signaling through 2‐methoxyestradiol, however, are cell type‐dependent. We investigated the effect of 2‐methoxyestradiol on several events associated with apoptosis in rat DS‐sarcoma cells. Translocation of the pro‐apoptotic protein Bax to mitochondria was identified as an initial apoptotic event that was accompanied by a decrease in mitochondrial transmembrane potential and the formation of reactive oxygen species (ROS) followed by mitochondrial release of apoptosis inducing factor and endonuclease G. In addition, 2‐methoxyestradiol treatment caused upregulation of death receptor ligands FasL and TNFα and induced caspase‐8 activation. The pan caspase inhibitor Z‐VAD‐FMK did not suppress apoptotic cell death, however, indicating that the major pro‐apoptotic effect of 2‐methoxyestradiol is mediated by a caspase‐independent mechanism. Furthermore, ROS do not seem to play a pivotal role in the toxic/apoptotic effect of 2‐methoxyestradiol in DS‐sarcoma cells because supplementation with various antioxidants provided only limit protection. Colony formation was not affected by antioxidants. Therefore, in DS‐sarcoma cells, the breakdown of mitochondrial integrity with the subsequent release of mitochondrial nucleases is the main factor in 2‐methoxyestradiol mediated cell death. © 2003 Wiley‐Liss, Inc.
Physical activity and renal cell cancer risk in a cohort of male smokers
Authors: Mahabir Somdat , Leitzmann Michael F. , Pietinen Pirjo , Albanes Demetrius , Virtamo Jarmo , Taylor Philip R.
Published: June 2004

Few studies have examined exercise in relation to risk of renal cell cancer. We examined the association between leisure‐time and occupational physical activity and renal cell cancer in a cohort of 29,133 male smokers 50–69 years of age in the Alpha‐Tocopherol, Beta‐Carotene (ATBC) Cancer Prevention Study. Physical activity was assessed at baseline using a self‐administered questionnaire that inquired about usual level of physical activity during leisure‐time and at work during the past year. Cox proportional hazards modeling was used to adjust simultaneously for known or suspected risk factors for renal cell cancer. During 12 years (354,407 person‐years) of follow‐up, 210 incident cases of renal cell cancer were identified. In age‐adjusted analysis, the RRs of renal cell cancer in increasing categories of leisure‐time physical activity (light, moderate and heavy) were 1.0, 0.89 (95% CI = 0.67–1.17) and 0.38 (95% CI = 0.15–0.94), respectively (p‐value for trend = 0.06). After adjustment for body mass index, energy intake, smoking, hypertension, education and fruit and vegetable intake, the multivariate RRs of renal cell cancer in increasing categories of leisure‐time physical activity (light, moderate and heavy), were 1.0, 0.89 (95% CI = 0.66–1.19), and 0.46 (95% CI = 0.18–1.13) (p‐value for trend = 0.12). Occupational physical activity was unrelated to renal cell cancer risk. These data suggest that recreational physical activity may play a role in the prevention of renal cell cancer in men. © 2003 Wiley‐Liss, Inc.
3‐OH flavone inhibition of epidermal growth factor‐induced proliferaton through blocking prostaglandin E2 production
Authors: Shen Shing‐chuan , Ko Ching‐huai , Hsu Kuo‐chou , Chen Yen‐chou
Published: June 2004

Epidermal growth factor (EGF) has been shown to induce proliferation in cells, however, the role of prostaglandin E2 (PGE2) plays in EGF‐induced proliferation in still unclear. EGF and PGE2 showed proliferation responses in epidermoid carcinoma cell A431 by MTT and [3H] thymidine incorporation assay. Activation of the EGF receptor and extracellular signal‐regulated protein kinases (ERK1/2), but not p38 and JNK, appeared 10 min after EGF treatment, whereas total amounts of ERK1/2, p38 and JNK remained unchanged in A431 cells, accompanied by induction of COX‐2 and PGE2 production. PD98059, a specific ERK1/2 inhibitor, inhibited EGF‐induced proliferation with concomitant decreases in ERK1/2 phosphorylation and COX‐2/PGE2 induction. Non‐steroid anti‐inflammatory drugs (NSAIDs) such as aspirin and diclofenac, a COX activity inhibitor, inhibited EGF‐induced proliferation by blocking PGE2 production. The addition of PGE2 reversed the inhibitory effects of PD98059, aspirin, and diclofenac on EGF‐induced proliferation. This suggests that COX‐2/PGE2 activation involves in EGF‐induced proliferation and locates at the downstream of ERK1/2 activation. Furthermore, the natural product, 3‐OH flavone, showed the most‐potent inhibitory activity on EGF‐induced proliferation among 9 structurally‐related compounds, and suppression of EGF receptor phosphorylation, ERK1/2 phosphorylation, and COX‐2/PGE2 production by 3‐OH flavone was identified. PGE2 addition attenuates the inhibitory activity of 3‐OH flavone on EGF‐induced proliferation by MTT assay and colony formation by soft agar assay. Additionally, 3‐OH flavone also showed more‐specific inhibition on EGF‐ than on fetal bovine serum (FBS)‐induced proliferation in A431 cells. Results of our present study provide evidence to demonstrate that PGE2 is an important downstream molecule in EGF‐induced proliferation, and 3‐OH flavone, which inhibits PGE2 production by blocking MAPK cascade, might reserve potential for development as an anti‐cancer drug. © 2003 Wiley‐Liss, Inc.
The role of angiogenesis, vascular maturation, regression and stroma infiltration in dormancy and growth of implanted MLS ovarian carcinoma spheroids
Authors: Gilead Assaf , Meir Gila , Neeman Michal
Published: June 2004

MLS ovarian epithelial carcinoma multicellular spheroids xenografted subcutaneously in CD‐1 nude mice displayed growth delay, or dormancy, of up to 52 days. In the study reported here, implanted MLS spheroids were used for testing the role of angiogenesis and vascular maturation in triggering the initiation of tumor progression. The kinetics and impact of neovascular maturation and functionality, in dormancy, and growth of MLS spheroid xenografts were studied noninvasively by BOLD contrast MRI. MR data were supported by histologic staining for biotinylated albumin as a blood pool marker and alpha‐smooth muscle actin (alpha‐SMA) as marker for perivascular mural cells. Although the tumor periphery showed higher levels of total and mature vasculature than normal skin, the fraction of mature out of the total vessels as detected by MRI vascular maturation index (VMIMRI) was significantly lower in the tumor both before and after tumor exit from dormancy. The neovasculature induced by the implanted spheroid was unstable and showed cycles of vessel growth and regression. Surprisingly, this instability was not restricted to the immature vessels, but rather included also regression of mature vessels. During dormancy, neovasculature was predominantly peripheral with no infiltration into the implanted spheroid. Infiltration of alpha‐SMA positive stroma cells into the spheroid was associated with functional vascularization and tumor growth. Thus, stroma infiltration and vascular maturation are an important checkpoint linking the angiogenic switch with initiation of tumor progression. © 2003 Wiley‐Liss, Inc.
Long term consequences of the 1944–1945 Dutch famine on the insulin‐like growth factor axis
Authors: Elias Sjoerd G. , Keinan‐Boker Lital , Peeters Petra H.M. , Van Gils Carla H. , Kaaks Rudolf , Grobbee Diederick E. , Van Noord Paulus A.H.
Published: June 2004

The insulin‐like growth factor axis is highly responsive to nutritional status and may be involved as one of the underlying mechanisms through which caloric restriction could affect cancer risk. High levels of circulating insulin‐like growth factor (IGF)‐I, or IGF‐I relative to IGF binding protein (IGFBP)‐3 have been related to various human cancer types. In a group of 87 postmenopausal women, we found that childhood exposure to the 1944–1945 Dutch famine was associated with increased plasma levels of IGF‐I and IGFBP‐3, whereas IGFBP‐1 and ‐2 levels were weakly decreased. These results are opposite to immediate responses seen under starvation and we hypothesize that this could indicate a permanent overshoot upon improvement of nutritional status after the famine. © 2003 Wiley‐Liss, Inc.
Rescue of death receptor and mitochondrial apoptosis signaling in resistant human NSCLC in vivo
Authors: Okouoyo Stella , Herzer Kerstin , Ucur Esat , Mattern Jürgen , Krammer Peter H. , Debatin Klaus‐Michael , Herr Ingrid
Published: June 2004

Non small cell lung carcinoma (NSCLC) is a highly lethal malignancy that often becomes resistant to chemotherapy. To determine whether alterations in apoptotic signaling might contribute to such resistance, we established in vitro and in vivo models for sensitive and resistant human NSCLC. We found that resistance is due to multiple defects found in expression of CD95‐L, CD95 and members of the Bcl‐2 and IAP family, as well as caspase‐8, ‐9 and ‐3 as examined by immunohistochemistry, Western blot analysis, gene array analysis and functional assays. Failure to activate death receptor, as well as mitochondrial apoptosis signaling, points to a central role of caspases. To restore apoptosis signaling we transfected NSCLC xenografts on nude mice with caspase‐8 and ‐9. This treatment strongly induced apoptosis per se and sensitized the tumors to cisplatin‐induced cell death. Thus, these findings indicate that re‐expression of caspases might be an effective strategy to restore sensitivity for chemotherapy in NSCLC in vivo. © 2003 Wiley‐Liss, Inc.
Parathyroid hormone‐related protein (PTHrP) is responsible for production of bone metastasis, but not visceral metastasis, by human small cell lung cancer SBC‐5 cells in natural killer cell‐depleted SCID mice
Authors: Miki Toyokazu , Yano Seiji , Hanibuchi Masaki , Kanematsu Takanori , Muguruma Hiroaki , Sone Saburo
Published: June 2004

We previously established an osteolytic bone metastasis model with multiorgan dissemination in natural killer (NK) cell‐depleted severe combined immunodeficient (SCID) mice using human small cell lung cancer cells (SBC‐5), which highly express the parathyroid hormone‐related protein (PTHrP). In our present study, we evaluated the role of PTHrP on bone metastasis by SBC‐5 cells using anti‐PTHrP neutralizing antibody (Ab). Anti‐PTHrP Ab did not affect the proliferation or cytokine production of SBC‐5 cells in vitro. Repeated intravenous injection with anti‐PTHrP Ab inhibited the formation of bone metastasis in a dose‐dependent manner, while the same treatment had no significant effect on the metastasis to visceral organs (lung, liver, kidney and lymph node). In addition, treatment with anti‐PTHrP Ab improved the elevated serum calcium level, associated with inhibition of osteolytic bone metastasis, suggesting that anti‐PTHrP Ab inhibited bone metastasis via suppression of bone resorption probably by neutralizing PTHrP. These findings suggest that PTHrP is essential for bone metastasis, but not visceral metastasis, by small cell lung cancer SBC‐5 cells. © 2003 Wiley‐Liss, Inc.
Immunoscreening of a cDNA library from a lung cancer cell line using autologous patient serum: Identification of XAGE‐1b as a dominant antigen and its immunogenicity in lung adenocarcinoma
Authors: Ali Eldib Ali Mohamed , Ono Toshiro , Shimono Michihide , Kaneko Miho , Nakagawa Kazuhiko , Tanaka Ryo , Noguchi Yuji , Nakayama Eiichi
Published: June 2004

By serologic identification of antigens by recombinant expression cloning (SEREX) analysis using an autologous lung adenocarcinoma cell line, OU‐LU‐6, as a cDNA library source, we demonstrated that XAGE‐1 was the dominant antigen recognized by serum from a patient. By immunoscreening, we obtained 38 positive cDNA clones consisting of 16 genes designated as OY‐LC‐1 to ‐OY‐LC‐16. OY‐LC‐1, represented by 18 clones, was identical to XAGE‐1. OY‐LC‐2 to ‐16, represented by either a single or 2 clones, were identical to known genes shown to be ubiquitously expressed in various normal tissues. RT‐PCR analysis showed that of 4 XAGE‐1 transcripts—XAGE‐1a, b, c and d—XAGE‐1b was expressed in OU‐LU‐6 dominantly. Furthermore, XAGE‐1b mRNA was expressed in 4 of 10 lung cancer tissues, whereas no expression was observed in normal tissues. Of 4 XAGE‐1b mRNA positive cancer tissues, 3 were adenocarcinoma and one was poorly differentiated squamous cell carcinoma. Of 32 sera from lung cancer patients, 8 sera were reactive with the XAGE‐1b product. Those 8 sera were from patients with adenocarcinoma. These findings indicated strong immunogenicity of XAGE‐1b in lung adenocarcinoma and suggested its potential use as a target for vaccine‐based immunotherapies. © 2003 Wiley‐Liss, Inc.
Assessment of highly angiogenic and disseminated in the peripheral blood disease in breast cancer patients predicts for resistance to adjuvant chemotherapy and early relapse
Authors: Giatromanolaki Alexandra , Koukourakis Michael I. , Kakolyris Stelios , Mavroudis Dimitris , Kouroussis Charalambos , Mavroudi Chrysa , Perraki Maria , Sivridis Efthimios , Georgoulias Vassilis
Published: June 2004

The assessment of tumor molecular features in combination with the detection of occult malignant cells may provide important clinical information, beyond the standard staging of breast cancer. Using a nested RT‐PCR technique, we assessed prospectively the presence of cytokeratin‐19 (CK19) mRNA positive cells in the blood of 100 operated patients with breast cancer before the initiation of adjuvant chemotherapy and local radiotherapy. Tissue samples were prospectively collected and analyzed for estrogen (ER) and progesterone (PgR) receptor, c‐erbB‐2 overexpression, mutant‐p53 and bcl‐2 protein accumulation, proliferation index and microvessel density (MVD). CK‐19 mRNA‐positive cells were detected in the peripheral blood of 33% of patients. Simultaneous display of high intratumoral MVD and of CK‐19 mRNA‐positive cells, which characterized highly angiogenic and disseminated in the peripheral blood (HAD) disease was noted in 25% of patients. Detection of CK‐19 positive cells was significantly associated with increased MVD (p = 0.002). In univariate analysis (median follow‐up 30 months) CK19 mRNA detection and MVD were the most significant factors related to a short relapse‐free survival (RFS), (p < 0.0001). In multivariate analysis, CK19 positivity, high MVD and c‐erbB‐2 overexpression were the only significant and independent variables associated with relapse (p = 0.0005, 0.03 and 0.04, respectively). Patients with HAD had an expected relapse rate close to 70% vs. <5% in the remaining patients irrespectively of the used chemotherapy regimen. The simultaneous presence of high MVD and CK19‐positive cells in the blood of patients with early breast is linked with poor prognosis, which cannot be improved with standard chemotherapy regimens. © 2003 Wiley‐Liss, Inc.
Regulation of carcinoma cell invasion by protein C inhibitor whose expression is decreased in renal cell carcinoma
Authors: Wakita Toshiaki , Hayashi Tatsuya , Nishioka Junji , Tamaru Hiroshi , Akita Nobuyuki , Asanuma Kunihiro , Kamada Haruhiko , Gabazza Esteban C. , Ido Masaru , Kawamura Juichi , Suzuki Koji
Published: June 2004

Protein C inhibitor (PCI), a member of the serine protease inhibitor family, is produced in various human tissues, including the liver, kidney and testis. In addition to inhibiting the anticoagulant protein C pathway, PCI also inhibits urinary plasminogen activator (uPA), which is a well‐known mediator of tumor cell invasion. In the present study, to clarify the biologic significance of PCI in the kidney, we compared the expression of PCI between human renal cell carcinoma (RCC) tissue and nontumor kidney tissue. The PCI antigen level in RCC tissue was found to be significantly lower than in nontumor kidney tissue, and expression of PCI mRNA was detected in normal renal proximal tubular epithelial cells (RPTEC), but not in RCC or in an RCC cell line (Caki‐1 cells). No differences were detected between the nucleotide sequence of the major cis‐elements in the promoter region of the PCI gene from nontumor kidney and RCC tissues, RPTEC and Caki‐1 cells, an RPTEC‐derived RCC cell line. The in vitro invasiveness of Caki‐1 cells transfected with a PCI expression vector was significantly decreased compared to mock‐transfected Caki‐1 cells, and it was blocked in the presence of anti‐PCI antibody. Since PCI itself did not affect the proliferation rate of Caki‐1 cells or cell expression of uPA in vitro, the effect of uPA, PCI, heat‐inactivated PCI and plasminogen activator inhibitor (PAI)‐1 on the invasive potential of cultured RCC cells was evaluated. The in vitro invasiveness of Caki‐1 cells, which express uPA, was significantly enhanced by the addition of uPA, and it was inhibited by anti‐uPA antibody, PCI and PAI‐1, but not by heat‐inactivated PCI. In addition, uPA activity was significantly decreased and uPA‐PCI complex level was significantly increased in the culture medium of PCI expression vector‐transfected Caki‐1 cells as compared to mock‐transfected Caki‐1 cells. These findings strongly suggest that PCI regulates the invasive potential of RCC cells by inhibiting uPA secreted by these cells. The results of our study suggest that PCI might be a potential therapeutic agent for inhibiting renal tumor invasion. © 2003 Wiley‐Liss, Inc.