Effect of nitrogen-containing derivatives of the plant triterpenes betulin and glycyrrhetic acid on the growth of MT-4, MOLT-4, CEM, and Hep G2 tumor cells

Derivatives of the available plant triterpenes glycyrrhetic acid and betulin (betulin succinates and amides of betulonic and 18beta-glycyrrhetic acids containing fragments of long-chain amino acids and a peptide) were synthesized. The inhibitory action of these compounds on the growth of MT-4, MOLT-4, CEM. and Hep G2 tumor cells and their effect on the apoptosis of these cells were studied. It was shown that betulonic acid amides are more effective inhibitors of the tumor cell growth than the corresponding amides of glycyrrhetic acid. It was also found that betulonic acid amides containing fragments of caprylic, pelargonic, and undecanoic acids are more effective inhibitors of tumor cell growth than betulinic acid. The 17-dipeptide derivative of betulonic acid N-{N-[3-oxo-20(29)-lupen-28-oyl]-9-aminononanoyl}-3-amino-3-phenylpropionic acid exhibited the maximum inhibitory activity toward the tumor cells studied. Data on the induction of apoptosis in tumor cells by betulin derivatives at a concentration of 10 microg/ml were obtained by flow cytometry. The amides of betulonic acid proved to be the most effective inducers of apoptosis.     

Synthesis,modification, and antimicrobial activity of the <Emphasis Type="Italic">N</Emphasis>-methylpiperazinyl amides of triterpenic acids

N-methylpyperazinyl amides of betulinic, platanic, glycyrrhetic, oleanolic, ursolic, and moronic acids were synthesized and modified. Betulin and betulonic acid showed antimicrobial activity against Staphylococcus aureus at a concentration of 90 mg/ml, and betulin manifested a bacteriostatic effect against Klebsiella pneumoniae at a concentration of 60 mg/ml. Among the studied N-methylpyperazinyl amides, the highest activity against S. aureus was observed for a betulonic acid derivative.     

Synthetic transformations of higher triterpenoids. XXX. Synthesis and cytotoxic activity of betulonic acid amides with fragments of nitroxyl radicals

Interaction of betulonic acid chloride with 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl, 3-amino-2,2,5,5-tetramethylpyrrolidine-1-oxyl, and 3-aminomethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl yielded the corresponding triterpene amides. The synthesized derivatives of betulonic acid were shown to exhibit a cytotoxic activity on models of the CEM-13, U-937, and MT-4 tumor cells. The concentration of the most active N-[3-oxo-28-norlup-20(29)-en-17-carbamoyl-(2,2,6,6-tetramethylpiperidine-4-yl)-1-oxyl that inhibited survival of the tumor cells by 50% (CCID₅₀) proved to be 5.7–33.1 μM.     

Synthesis and Antitumor Activity of Cyclopropane Derivatives of Betulinic and Betulonic Acids

New cyclopropane derivatives of betulin were synthesized by attachment of dichlorocarbenes or dibromocarbenes to the double bond of betulin diacetate, followed by the deprotection of hydroxyl groups. The betulin cyclopropane derivative was obtained from 20,29-dihydro-20,29-dichloromethylenebetulin by treatment with lithium in tert-butanol. These compounds were converted into the corresponding derivatives of betulonic acid by oxidation with chromium trioxide. The reduction of oxo group with sodium borohydride led to the corresponding derivatives of betulinic acid. 20,29-Dihydro-20,29-dichloromethylenebetulinic acid proved to be the most cytotoxic toward human melanoma of the Colo 38 and Bro lines and human ovarian carcinoma of the CaOv line (IC₅₀ 10 μM). 20,29-Dihydro-20,29-dibromomethylenebetulinic acid inhibited the growth of the Bro melanoma cell line and the CaOv carcinoma cell line practically by 50% at a concentration of 10 μM. The other derivatives of betulinic and betulonic acids were active toward all of the three cancer cell lines at concentrations higher than 10 μM.__________Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 3, 2005, pp. 320–325.Original Russian Text Copyright © 2005 by Symon, Veselova, Kaplun, Vlasenkova, Fedorova, Lyutik, Gerasimova, Shvets.     

Synthesis and Antiviral Activity of Betulonic Acid Amides and Conjugates with Amino Acids

Betulonic acid amides with aliphatic and heterocyclic amines and with L-amino acids were synthesized by the acid chloride method. Betulonic acid amide and L-methionine derivatives of betulonic acid and its 3-oxime effectively inhibit the influenza A virus. Betulonic acid octadecylamide is active against the herpes simplex Type 1 virus. The conjugate of betulonic acid 3-oxime with L-methionine is also active toward HIV-1. The tested compounds mainly show no activity toward the ECHO6 virus, which is devoid of a coat.     

Synthesis and antitumor activity of cyclopropane derivatives of betulinic and betulonic acids

New cyclopropane derivatives of betulin were synthesized by attachment of dichlorocarbenes or dibromocarbenes to the double bond of betulin diacetate, followed by the deprotection of hydroxyl groups. The betulin cyclopropane derivative was obtained from 20,29-dihydro-20,29-dichloromethylenebetulin by treatment with lithium in tert-butanol. These compounds were converted into the corresponding derivatives of betulonic acid by oxidation with chromium trioxide. The reduction of oxo group with sodium borohydride led to the corresponding derivatives of betulinic acid. 20,29-Dihydro-20,29-dichloromethylenebetulinic acid proved to be the most cytotoxic toward human melanoma of the Colo 38 and Bro lines and human ovarian carcinoma of the CaOv line (IC50 10 microM). 20,29-Dihydro-20,29-dibromomethylenebetulinic acid inhibited the growth of the Bro melanoma cell line and the CaOv carcinoma cell line practically by 50% at a concentration of 10 microM. The other derivatives of betulinic and betulonic acids were active toward all of the three cancer cell lines at concentrations higher than 10 microM. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2005, vol. 31, no. 3; see also http://www.maik.ru.     

Synthesis and Antiviral Activity of Ureides and Carbamates of Betulinic Acid and Its Derivatives

Ureides and carbamates of betulinic acid and its derivatives were prepared in good yields by interaction of betulinic acid, betulonic acid, and betulonic acid 3-oxime with amines, amino acids, and alcohols. Ureides of betulonic acid containingL-Val and L-Met residues were found to be effective against herpes simplex type 1 virus.     

Synthesis and biological activity of new glycyrrhizic acid conjugates with amino acids and dipeptides

New glycyrrhizic acid (GA) conjugates were synthesized with the use of tert-butyl esters of amino acids or benzyl esters of dipeptides; they contained two residues of L-amino acids (Met, Phe, Pro, and Ile or dipeptides Gly-Leu and Gly-Phe). Activation of GA carboxy groups was carried out with the help of N-hydroxysuccinimide, N,N′-dicyclohexylcarbodiimide, or N-hydroxybenzotriazole with dicyclohexylcarbodiimide. A proline-containing GA derivative is a low-toxic substance; it raises the level of agglutinins by 3.7 times in the blood of mice and 3 times that of hemolysins compared with the control. Dipeptide GA derivatives possess an expressed anti-HIV-1 activity in cultures of MT-4 cells and are 90-70 times less cytotoxic than azidothymidine. The selectivity index of the compounds exceeds those of GA by 110 and 34 times, respectively.     

Structure-functional analysis of interactions of terminal deoxynucleotidyl transferase with new non-nucleoside substrates

New non-nucleoside esters of phosphoric acid containing various hydrophobic groups, namely (1) N-(2-tripticencarbonyl)-4-aminobutyl; (2) 5-phenylsubstituted N-(2,4-dinitrophenyl)-4-aminobutyl; (3) N-(4-phenylbenzoyl)- and N-(4-(N-benzylamino)benzoyl)-2-aminoethyl groups, as well as (4) diphenylmethyl and fluorenyl groups were synthesized and studied as substrates of terminal deoxynucleotidyl transferase. With the exception of the two latter derivatives, all the analogues displayed substrate properties and could incorporate into the deoxyoligonucleotide 3′-end. As it was shown in biochemical experiments and by computer modeling, a linker joining the triphosphate and hydrophobic fragments of the molecule was necessary for these compounds to display substrate properties.     

c-FLIP is involved in tumor progression of peripheral T-cell lymphoma and targeted by histone deacetylase inhibitors

Background

Peripheral T-cell lymphomas (PTCLs) are often aggressive tumors and resistant to conventional chemotherapy. Dysregulation of extrinsic apoptosis plays an important role on tumor cell sensitivity to chemotherapeutic agents. Cellular FLICE inhibitory protein (c-FLIP) is a key regulator of extrinsic apoptotic pathway.

Methods

c-FLIP expression was assessed by real-time PCR and compared according to clinical parameters in patients with PTCLs. The relation of c-FLIP to tumor cell apoptosis mediated by histone deacetylases inhibitors (HDACIs) and the possible mechanism were examined in T-lymphoma cell lines and in a murine xenograft model.

Results

c-FLIP was overexpressed and associated with decreased tumor TRAIL/DR5 expression, elevated serum lactate dehydrogenase level and high-risk International Prognostic Index of the patients. In vitro, molecular silencing of c-FLIP by specific small-interfering RNA increased TRAIL/DR5 expression, enhanced T-lymphoma cell apoptosis and sensitized cells to chemotherapeutic agents. However, HDACIs valproic acid (VPA) and suberoylanilide hydroxamic acid (SAHA) could downregulate c-FLIP expression and triggered extrinsic apoptosis of T-lymphoma cells, through inhibiting NF-κB signaling and interrupting P50 interaction with c-FLIP promoter. As Class I HDACIs, both VPA and SAHA inhibited HDAC1, resulting in P50 inactivation and c-FLIP downregulation. In vivo, oral VPA treatment significantly retarded tumor growth and induced in situ apoptosis, consistent with inhibition of HDAC1/P50/c-FLIP axis and increase of TRAIL/DR5 expression.

Conclusions

c-FLIP overexpression in PTCLs protected tumor cells from extrinsic apoptosis and contributed to tumor progression. Although linking to chemoresistance, c-FLIP indicated tumor cell sensitivity to HDACIs, providing a potential biomarker of targeting apoptosis in treating PTCLs.

     

Synthesis and antiviral activity of ureides and carbamates of betulinic acid and its derivatives

Ureides and carbamates of betulinic acid and its derivatives were prepared in good yields by interaction of betulinic acid, betulonic acid, and betulonic acid 3-oxime with amines, amino acids, and alcohols. Ureides of betulonic acid containing L-Val and L-Met residues were found to be effective against herpes simplex type 1 virus. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2003, vol. 29, no. 6; see also http://www.maik.ru.     

Study of skin anti-ageing and anti-inflammatory effects of dihydroquercetin, natural triterpenoinds, and their synthetic derivatives

Accessible triterpenoids of ursane and lupane series, the flavonoid dihydroquercetin and their synthetic derivatives with polar substituents were tested in vitro for inhibition of collagenase 1 (MMP-1) in UVB irradiation assay. Ursolic acid and uvaol disuccinate were the most active inhibitors in the ursane series. In the lupane series, the best inhibition was manifested by carboxymethyl ester of betulonic acid and betulin succinates. Down- regulation of MMP-1 by dihydroquercetin and its synthetic derivatives surpassed the activity of a standard (retinoic acid).     

Neuro-and psychotropic activity of <Emphasis Type="Italic">N</Emphasis>-uronoylamino acids and <Emphasis Type="Italic">N</Emphasis>-uronoylpeptides

Peculiarities of the rat behavior were studied in a series of experimental stress models after a systemic administration of new N-uronoyl derivatives of amino acids. The psychotropic effect was shown to be determined by the nature of the amino acid fragment. N-(1,2:3,4-Di-O-isopropylidene-α-D-galactopyraneuronoyl)-glycylglycine exhibited an anxiolytic effect more pronounced than that of pyracetam, whereas N-(1,2:3,4-di-O-isopropilidene-α-D-galactopyranuronoyl)-glycylglutamic acid has antidepressant action stronger than that of amitriptyline. Mechanisms for the psychotropic effects of the examined derivatives are discussed.     

Synthesis and Antiviral Activity of Hydrazides and Substituted Benzalhydrazides of Betulinic Acid and Its Derivatives

New nitrogen-containing derivatives of betulinic and betulonic acids, hydrazides and N"-benzalhydrazides, were synthesized. Their antiviral activities toward viruses of influenza A virus, herpes simplex type I virus, enterovirus ECHO6, and HIV-1 were studied in vitro. Betulinic acid 3-oxime was found to have the highest activity against the influenza virus. Betulonic acid, betulinic acid 4-chlorobenzalhydrazide, betulonic acid 3-oxime benzalhydrazide, and betulinic acid hydrazide inhibited the replication of herpes simplex type I virus. Betulinic acid hydrazide also showed antiviral activity toward HIV-1. All the derivatives of betulinic acid under study displayed a low antiviral activity toward enterovirus ECHO6.     

Synthesis of triterpenoid triazine derivatives from allobetulone and betulonic acid with biological activities

The synthetic transformation and modification of natural products with the aim to improve the biological properties is an area of current interest. The triterpenoids betulin and betulinic acid are very abundant in nature and now are commercially available. In our study, starting from betulin and betulinic acid, we obtained allobetulone and betulonic acid in a few synthetic steps. The ketone function at the A-ring was used as the starting point for the synthesis of a series of 1,2,4-triazine-fused triterpenoids. The alkylation and Liebeskind–Srogl coupling were used for further substitution of 1,2,4-triazines, and the intramolecular hetero Diels–Alder reaction leads to interesting fused thienopyridine derivatives. All new compounds were tested for their cytostatic activities against murine leukemia L1210, human cervix carcinoma HeLa and human lymphoblast CEM tumor cells. The results show that some triterpenoid triazine betulonic acid derivatives have a promising cytostatic activity in vitro and could be used as potential leads for the development of new type of anti-cancer agents. Several compounds were also endowed with anti-HCMV activity in the low micromolar range.     

Lamotrigine Attenuates Proteasome Inhibition-Induced Apoptosis by Suppressing the Activation of the Mitochondrial Pathway and the Caspase-8- and Bid-Dependent Pathways

Proteasome impairment has been shown to be involved in neuronal degeneration. Antiepileptic lamotrigine has been demonstrated to have a neuroprotective effect. However, the effect of lamotrigine on the proteasome inhibition-induced neuronal cell death has not been studied. Therefore, we assessed the effect of lamotrigine on the proteasome inhibition-induced neuronal cell apoptosis in relation to cell death process using differentiated PC12 cells and SH-SY5Y cells. The proteasome inhibitors MG132 and MG115 induced a decrease in the levels of Bid and Bcl-2 proteins, an increase in the levels of Bax and p53, loss of the mitochondrial transmembrane potential, cytochrome c release and activation of caspases (-8, -9 and -3). The addition of lamotrigine reduced the proteasome inhibitor-induced changes in the apoptosis-related protein levels, production of reactive oxygen species, depletion and oxidation of glutathione (GSH), and cell death in both cell lines. Lamotrigine and N-acetylcysteine alone did not affect the levels of 26S proteasome and activity of 20S proteasome. MG132 did not alter the levels of 26S proteasome but decreased activity of 20S proteasome. Lamotrigine and N-acetylcysteine attenuated MG132-induced decrease in the activity of 20S proteasome. The results show that lamotrigine appears to suppress the proteasome inhibitor-induced apoptosis in PC12 cells by suppressing the activation of the mitochondrial pathway and the caspase-8- and Bid-dependent pathways. The suppressive effect of lamotrigine appears to be associated with its inhibitory effect on the production of reactive oxygen species, the depletion and oxidation of GSH and the activity reduction of 20S proteasome.     

Epimerization of hydroxyl group in the lupan series of triterpenes

Two methods of obtaining of 3 alpha-betulinic acid and related compounds from their 3 beta-epimers were studied: the reaction of bimolecular substitution and the stereoselective reduction of 3-ketoderivatives. The substitution of acyloxy by formyloxy group in 3-O-tosyllupeol or of the betulin hydroxyl by benzoyloxy group resulted only in delta 2, 3-elimination products, with none of the expected products of bimolecular substitution being found. The catalytic hydrogenation of betulonic acid over Raney nickel resulted only in reduction of the isopropenyl double bond, whereas the use of 5% Ru/C gave a 60:40 mixture of epimers of dihydrobetulinic acid. Practically the same mixture of betulinic acid epimers was obtained when reducing betulonic acid with L-Selectride. The cytotoxic activity of 3 alpha-betulinic acid increased toward melanoma Bro cells and decreased toward melanoma MS cells.     

Synthesis and cytotoxicity of triterpene seven-membered cyclic amines

3-Deoxy-3a-homo-3a-aza derivatives of betulin and erythrodiol have been synthesized from betulonic and oleanonic acids. 3-Deoxy-3a-homo-3a-aza-28-hydroxy-12(13)-oleanene showed the highest antineoplastic activity of the broad spectrum in vitro; the results of an extensive examination of the derivative in vitro enable one to recommend it for in vivo tests. The modification of the compound in the position C28 by the introduction of a methoxycinnamoyl fragment led to the loss of the antineoplastic activity. As a whole, 3-deoxy-3a-homo-3a-aza derivatives of betulin [3-(aminopropyl)-, 28-(2-carboxyethyl)carboxy-, and 28-cinamoyloxy-] exhibited a moderate antineoplastic activity toward large intestine cancer, breast cancer, and leukemia cells.     

桦木酮酸对肿瘤细胞SGC-7901、HepG-2及S180荷瘤小鼠肿瘤细胞的影响

为研究桦木酮酸体外对SGC-7901、HepG-2及体内对S180荷瘤小鼠的影响,采用MTT与肿瘤细胞集落形成能力实验观察桦木酮酸对HepG-2和SGC-7901作用。通过抑瘤率观察其对S180荷瘤小鼠的影响;HE染色观察其对S180肿瘤细胞形态学的影响。结果显示：桦木酮酸可抑HepG-2和SGC-7901细胞的生长,MTT与肿瘤集落形成能力实验测得其IC50分别为68．14和110．77μmol／L。连续给药8d后,150和75ms／kg／d剂量的桦木酮酸对S180的抑制率分别为68．3％和41．5％（P〈0．05）;HE染色发现肿瘤细胞表现较为明显的胀亡现象：细胞淡染、细胞体积增大,细胞核结构相对完整。提示桦木酮酸体内、外对肿瘤细胞均有一定的抑制作用,其作用可能与其引起肿瘤细胞胀亡有关。     

Synthesis and antiviral activity of amides and conjugates of betulonic acid with amino acids

Betulonic acid amides with aliphatic and heterocyclic amines and with L-amino acids were synthesized by the acid chloride method. Betulonic acid amide and L-methionine derivatives of betulonic acid and its 3-oxime effectively inhibit the influenza A virus. Betulonic acid octadecylamide is active against the herpes simplex type 1 virus. The conjugate of betulonic acid 3-oxime with L-methionine is also active toward HIV-1. The tested compounds mainly show no activity toward the ECHO6 virus, which is devoid of a coat. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 1; see also http://www.maik.ru.