Biomedical subjects

Paolo La Colla

Publications and source records attributed to Paolo La Colla.

35 records · Page 2Linked to original sources

PubMed2004

Anti-HIV-1 activity of pyrryl aryl sulfone (PAS) derivatives: synthesis and SAR studies of novel esters and amides at the position 2 of the pyrrole nucleus.

A SAR study has been performed in order to evaluate how much the ester function could be a determinant for the anti-human immunodeficiency virus type-1 activity of pyrryl aryl sulfones (PASs), a potent family of non-nucleoside reverse transcriptase (RT) inhibitors discovered in the last years. Twenty-three new esters were prepared with the aim to enhance the inhibitory potency of 4a and 4c, two PAS agents endowed with good activity (EC50 = 0.14 microM) and deprived of cytotoxicity up to >200 microM. None of test derivatives was as potent as 4a and 4c and lacked of selectivity due to their higher cytotoxicity (compounds 22-25). Antiviral activity correlate with an ester ramified chain.

Amides↗

PubMed2004

New 6-nitroquinolones: synthesis and antimicrobial activities.

Pursuing our searches on quinolonecarboxylic acids we used a simple three-step one pot procedure to synthesize novel 1,7-disubstituted-6-nitroquinolones. The new derivatives were tested against Mycobacterium tuberculosis and Mycobacterium avium complex (MAC) as well as against both gram-positive and gram-negative bacteria. In vitro assays showed some derivatives were endowed with good inhibiting activities against tested mycobacteria. Some derivatives were also found more potent than ciprofloxacin and ofloxacin (used as reference drugs) against gram-positive bacteria.

Anti-Bacterial Agents↗

PubMed2004

Synthesis, physicochemical and pharmacokinetic studies of potential prodrugs of beta-L-2'-deoxycytidine, a selective and specific anti-HBV agent.

beta-L-2'-Deoxycytidine (beta-L-dC) is a potent, selective and specific anti-hepatitis B virus (HBV) agent. To improve its oral bioavailability, several derivatives involving sugar or base acylation, as well N4-derivatization with an N,N-(dimethylamino)methylene function, were synthesized. The physicochemical characteristics (including chemical stabilities, solubilities and distribution coefficient values) and pharmacokinetics of these compounds were determined and compared with those of the parent drug, beta-L-dC.

Acylation↗

PubMed2003

Synthesis and biological evaluation of benzo[d]isothiazole, benzothiazole and thiazole Schiff bases.

Three new series of benzo[d]isothiazole, benzothiazole and thiazole Schiff bases were synthesized and tested in vitro with the aim of identifying novel lead compounds active against emergent and re-emergent human and cattle infectious diseases (AIDS, hepatitis B and C, tuberculosis, bovine viral diarrhoea) or against drug-resistant cancers (leukaemia, carcinoma, melanoma, MDR tumors) for which no definitive cure or efficacious vaccine is available at present. In particular, these compounds were evaluated in vitro against representatives of different virus classes, such as a HIV-1 (Retrovirus), a HBV (Hepadnavirus) and the single-stranded RNA(+) viruses Yellow fever virus (YFV) and Bovine viral diarrhoea virus (BVDV), both belonging to Flaviviridae. Title compounds were also tested against representatives of Gram-positive and Gram-negative bacteria (Staphylococcus aureus, Salmonella spp.), various atypic mycobacterial strains (Mycobacterium fortuitum and Mycobacterium smegmatis), yeast (Candida albicans) and mould (Aspergillus fumigatus). None of the compounds showed antiviral or antimicrobial activity. The benzo[d]isothiazole compounds showed a marked cytotoxicity (CC(50)=4-9 microM) against the human CD4(+) lymphocytes (MT-4) that were used to support HIV-1 growth. For this reason, the most cytotoxic compounds of this series were evaluated for their antiproliferative activity against a panel of human cell lines derived from haematological and solid tumors. The results highlighted that all the benzo[d]isothiazole derivatives inhibited the growth of leukaemia cell lines, whereas only one of the above mentioned compounds (1e) showed antiproliferative activity against two solid tumor-derived cell lines.

Animals↗

PubMed2003

New benzo[g]isoquinoline-5,10-diones and dihydrothieno [2,3-b]naphtho-4,9-dione derivatives: synthesis and biological evaluation as potential antitumoral agents.

Novel antitumoral agents with quinonic structure were synthesized and evaluated for their in vitro cytotoxic activities. This study examines the cytotoxic activities of several aryl benzo[g]isoquinoline-5,10-dione derivatives and a number of aminoacyl dihydrothieno[2,3-b]naphtho-4,9-dione (DTNQ) derivatives containing amino acids in position 3 of the ring system. Compound 6 showed remarkable cytotoxic activity at submicromolar concentration not only against several human leukaemia and solid tumour cell lines, but also toward sensitive and resistant human cell lines.

Amino Acids↗

PubMed2003

Synthesis and antiproliferative activity of basic thioanalogues of merbarone.

Three series of 5-substituted 1,3-diphenyl-6-(omega-dialkyl- and omega-cyclo-aminoalkyl)thio-2-thiobarbiturates (11-13) were synthesized as polysubstituted thioanalogues of merbarone, a topoisomerase II inhibitor acting on the catalytic site. To better understand pharmacophore requirements, a forth series of conformationally constrained analogues 14 was also prepared. Derivatives 11b,e, 14b,e,h,i,j were active in the low micromolar concentration range (IC(50): 3.3-4.3 microM), whereas compounds 11a,c,d,f,h,j and 13a,b,d,g,j and 14a,d,f showed IC(50) values between 10 and 15.5 microM. In contrast, compounds 12a-c,g-j, 13e,f,h and 14k were inactive. Cytotoxicity data provided from N.C.I. on selected compounds provided evidence that 11b,d, 13d,g and 14b,d,f,h,i,j were endowed with potent antiproliferative activity against leukemia and prostate cell lines (GI(50) up to 0.01 microM). In general, bicyclic derivatives 14 were up to 10-fold more potent than monocyclic counterparts against solid tumor-derived cell lines. SAR studies indicated that, in general, a certain tolerability in length of the alkyl side chains and in shape of distal amines is allowed in the four series, but in the monocyclic derivatives (11-13) antiproliferative activity was strongly affected by the nature of the 5-substituents (COOC(2)H(5)>COCH(3)>>C(6)H(5)). Compounds 11b and 14b were also evaluated against KB cell subclones expressing altered levels of topoisomerases or the multidrug resistance phenotype (MDR). In both cases the above compounds showed a decrease in potency. In enzyme assays, 11b and 14b turned out to be inhibitors of topoisonerase II as merbaron.

Antineoplastic Agents↗

PubMed2003

Novel indolyl aryl sulfones active against HIV-1 carrying NNRTI resistance mutations: synthesis and SAR studies.

The potent anti-HIV-1 activities of L-737,126 (2) and PAS sulfones prompted us to design and test against HIV-1 in acutely infected MT-4 cells a number of novel 1- and 3-benzenesulfonylindoles. Indoles belonging to the 1-benzenesulfonyl series were found poorly or totally inactive. On the contrary, some of the 3-benzenesulfonyl derivatives turned out to be as potent as 2, being endowed with potencies in the low nanomolar concentration range. In particular, (2-methylphenyl)sulfonyl (72) and (3-methylphenyl)sulfonyl (73) derivatives showed EC(50) values of 1 nM. Introduction of two methyl groups at positions 3 and 5 of the phenyl ring of 2 furnished derivatives (80 and 83) which showed very potent and selective anti-HIV-1 activity not only against the wt strain, but also against mutants carrying NNRTI-resistant mutations at positions 103 and 181 of the reverse transcriptase gene.

Anti-HIV Agents↗

PubMed2003

Design, synthesis, SAR, and molecular modeling studies of acylthiocarbamates: a novel series of potent non-nucleoside HIV-1 reverse transcriptase inhibitors structurally related to phenethylthiazolylthiourea derivatives.

A novel series of potent, selective HIV-1 N-acylthiocarbamate (ATC) nonnucleoside reverse transcriptase inhibitors (NNRTIs) is described. The title compounds were synthesized through a highly convergent, one-pot procedure. In cell-based assays, the lead compound (17c) prevented the HIV-1 multiplication with an EC(50) of 8 microM. The lead optimization strategy was developed by single or multiple modifications of the three molecular portions, in which 17c was notionally divided. Molecular modeling studies led to the synthesis of O-(2-phthalimidoethyl)-N-(p-substituted phenyl)-N-acylthiocarbamates, which showed in vitro activities against HIV-1 in the low nanomolar range. Nevertheless, the title compounds retained low potency against HIV-1 strains carrying mutations (K103R, Y181C, and K103N/Y181C) responsible for NNRTI resistance. The hypothetical docking model of RT/17c and RT/25c, derived from X-ray crystallographic structure of a PETT derivative in complex with HIV-1 RT, revealed that the model structures of ATCs do not approximate the NNRTI butterfly-like conformation. Analysis of these hypotetical complexes helps to rationalize some SARs and resistance data.

Cell Line↗

PubMed2003

Quinoxaline chemistry. Part 16. 4-substituted anilino and 4-substituted phenoxymethyl pyrrolo[1,2-a]quinoxalines and N-[4-(pyrrolo[1,2-a]quinoxalin-4-yl)amino and hydroxymethyl]benzoyl glutamates. Synthesis and evaluation of in vitro biological activity.

Twenty eight pyrrolo[1,2-a]quinoxalines bearing at position 4 various substituents related to the moieties present in classical and non classical antifolic agents were prepared and evaluated in vitro for antiproliferative activity. In an in vitro screening performed at NCI, several compounds emerged as potent antiproliferative agents at concentrations ranging between 10 and 100 microM. Interestingly, some of these compounds proved active also against bovine and murine DHFR (Farmaco 53 (1998) 480). More recently, a compound of classical antifolate type has been reported to be a potent inhibitor of hDHFR in vitro (Farmaco 58 (2003) 51). We then synthesized new derivatives that, in our hands, were endowed with in vitro antiproliferative activities as low as 3.4 microM against a panel of cell lines derived from hematological and solid tumours. In addition, a complete screening of cytotoxicity, antiretroviral HIV-1 and antimicrobial activity has been carried out.

Aniline Compounds↗

PubMed2003

Design, synthesis and in vitro cytotoxicity of a cis-dichloroplatinum (II) complex linked to the minor groove binder stallimycin.

Two potentially hydrophilic platinum (II) complexes 10 and 11 bound to the minor groove binder stallimycin (distamycin A, CAS 636-47-5) by L-cysteine and D,L-2,3-diaminopropionic acid have been synthesized. The in vitro cytotoxicity of both these complexes was evaluated against several cell lines. None of the synthesized platinum complexes showed greater activity than that of cisplatin (cis-DDP, 1) (CAS 15663-27-1). Interestingly, the free ligands 6 and 9 were more active than the related platinum complexes 10 and 11, respectively, with respect to RAJI, CCRF-CEM and MOLT-4 human leukaemia cell lines.

Antineoplastic Agents↗

PubMed2002

Antitumor agents. 1. Synthesis, biological evaluation, and molecular modeling of 5H-pyrido[3,2-a]phenoxazin-5-one, a compound with potent antiproliferative activity.

The iminoquinone is an important moiety of a large number of antineoplastic drugs and plays a significant role in the nucleus of actinomycins, powerful, highly toxic, natural antibiotics that target DNA as intercalating agents. A series of polycyclic iminoquinonic compounds, 2-amino-3H-phenoxazin-3-one (1), 2-amino-1,9-diacetyl-3H-phenoxazin-3-one (2), 2-acetylamino-3H-phenoxazin-3-one (3), 3H-phenoxazin-3-one (4), 5H-pyrido[3,2-a]phenoxazin-5-one (5), and 5H-pyrido[3,2-a]phenothiazin-5-one (6), strictly related to the actinomycin chromophore, were synthesized for developing new anticancer intercalating drugs. The antiproliferative activity of these compounds, evaluated against representative human liquid and solid neoplastic cell lines, showed that 5 and its isoster 6 were the most active compounds inhibiting cell proliferation in a submicromolar range. Compound 5 was also evaluated against KB subclones (KBMDR, KB7D, and KBV20C), which overexpress the MDR1/P-glycoprotein drug efflux pump responsible for drug resistance. All the above KB subclones did not show altered sensitivity to the antiproliferative activity of 5. UV-vis and (1)H NMR spectroscopy experiments support the phenoxazinone 5/DNA binding. Molecular mechanics methods were used to build a three-dimensional model of the 5/[d(GAAGCTTC)]2 complex. Electrostatic interactions between the hydrogen of the positively charged pyridine nitrogen of 5 and the negatively charged oxygen atoms (O4' and O5') of the cytosine C5 residue together with stacking forces contribute to the high antiproliferative activity. The metal(II)-assisted synthesis procedure of 5 is described, and the formation mechanism is proposed.

Antineoplastic Agents↗

PubMed2002

Antitumor agents. 2. Synthesis, structure-activity relationships, and biological evaluation of substituted 5H-pyridophenoxazin-5-ones with potent antiproliferative activity.

New antiproliferative compounds, 5H-pyrido[3,2-a]phenoxazin-5-ones (1-10), 5H-benzophenoxazin-5-one (11), 5H-pyrido[2,3-a]phenoxazin-5-one (12), 5H-pyrido[3,4-a]phenoxazin-5-one (13), and 5H-pyrido[4,3-a]phenoxazin-5-one (14), were synthesized and evaluated against representative human neoplastic cell lines. The excellent cytotoxic activity of these polycyclic phenoxazinones, structurally related to the actinomycin chromophore, is discussed in terms of structural changes made to rings A and D (Chart 1). Electron-withdrawing or electron-donating substituents were introduced at different positions of ring A to probe the electronic and positional effects of the substitution. A nitro group in R(2) or in R(1) increases the cytotoxic activity, whereas electron-donating methyl groups in any position lead to 10- to 100-fold decreasing of the activity. The low antiproliferative activity of benzophenoxazinone 11 and pyridophenoxazinones 13 and 14 confirms the crucial role of pyridine nitrogen in the W position of ring D in DNA binding. The unexpected high activity exhibited by 12, which has the nitrogen in the X position, could be ascribed to a different mechanism of action, which needs further investigation.

Antineoplastic Agents↗

PubMed2002

Synthesis, biological evaluation, and binding mode of novel 1-[2-(diarylmethoxy)ethyl]-2-methyl-5-nitroimidazoles targeted at the HIV-1 reverse transcriptase.

A novel series of 1-[2-(diarylmethoxy)ethyl]-2-methyl-5-nitroimidazole (DAMNI) analogues were synthesized and tested in cell-based assays and in enzyme assays against HIV-1 recombinant reverse transcriptase (RT). Preparation of the new derivatives was performed by reacting the appropriate benzhydrols or the corresponding bromides with 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole or the 3-hydroxypropyl homologue. Several compounds showed anti-HIV-1 activity in the submicromolar range. Structure-activity relationship studies suggested that meta substitution at one phenyl ring of the diarylmethane moiety strongly influences the antiviral activity. The 3,5-disubstitution at the same phenyl ring led to less potent derivatives. Molecular modeling and docking studies within the RT non-nucleoside binding site confirmed that DAMNIs, similar to other NNRTIs such as TNK-651 and delavirdine (BHAP U90152), assume a butterfly-like conformation that appears to be halfway between that of classical NNRTIs, such as nevirapine, HEPT, TBZ, TIBO, and DABOs, and the conformation of BHAPs. In particular, the diphenylmethane moiety mimics the wings whereas the 1-(2-methyl-5-nitroimidazolyl)ethane portion resembles the BHAP 5-methanesulfonamidoindole-2-carbonylpiperazine portion.

Animals↗

PubMed2002

Synthesis and antifungal properties of N-[(1,1'-biphenyl)-4-ylmethyl]-1H-imidazol-1-amine derivatives.

In the course of a study on 1H-imidazol-1-amine derivatives as antifungal agents, we found that N-[(1,1'-biphenyl)-4-ylmethyl]-N-[(2,4-dichlorophenyl)methyl]-1H-imidazol-1-amine (1a) exhibited promising activities. In order to explore more in detail the structure-activity relationship of this new class of antifungal agents, we report now the synthesis and the biological activity of new analogues (1b-k) of compound 1a. The synthesis was performed using N-[(1,1'-biphenyl)-4-ylmethyl]-1H-imidazol-1-amine as starting material which was reacted with the proper arylmethyl halide. Most of the newly synthesized imidazolamines exhibited both fungal growth inhibition activity and cellular selectivity.

Antifungal Agents↗

PubMed2002

Design, synthesis and QSAR studies on N-aryl heteroarylisopropanolamines, a new class of non-peptidic HIV-1 protease inhibitors.

A series of N-aryl heteroarylisopropanolamines in which an indole or a 3-arylpyrrole moiety was linked to an aryl group through an isopropanolamine linker, were designed and synthesized as potential anti-HIV-1-PR agents. Series was tested for their ability in blocking PR activity. As a rule, indole derivatives of class 1 exhibited more potency than pyrrole analogues of class 2 while tert-butylamide substituents increased anti-PR potency. In fact, bis tert-butylamide 1e showed the highest activity with IC(50)=25 microM. Even if not very potent, a simple class of anti-PR agents, with a facile synthetic pathway was discovered. QSAR studies on isopropanolamines 1 and 2 were performed in comparison with diarylbutanols, a new class of non peptidic anti-PR agents, recently discovered by Agouron Pharmaceuticals. QSAR and CoMFA models based on 30 diarylbutanols used as a training set were developed. The obtained models were used to investigate the binding mode of the newly synthesized derivatives 1 and 2. The results of this study suggest that N-aryl heteroarylisopropanolamines bind to the PR active site similarly to the diarylbutanols of Agouron.

Butylamines↗

PubMed2002

Synthesis and studies of 3'-C-trifluoromethyl nucleoside analogues bearing adenine or cytosine as the base.

3'-Deoxy-3'-C-CF3, 2',3'-dideoxy-3'-C-CF3 and 2',3'-unsaturated-3'-C-CF3 nucleoside derivatives of adenosine and cytidine have been synthesized. All these derivatives were prepared by glycosylation of adenine and uracil with a suitable peracylated 3-trifluoromethyl sugar precursor. The resulting protected nucleosides were subject to appropriate chemical modifications to afford the target nucleoside derivatives. Additionally, the chemical stability in acidic and neutral media of the 2',3'-dideoxy-3'-C-CF3 and 2',3'-unsaturated-3'-C-CF3 nucleoside derivatives of adenosine was compared to that of their parent nucleosides 2',3'-dideoxyadenosine (ddA) and 2',3'-dideoxy-2',3'-didehydroadenosine (d(4)A). Our results confirm that addition of a trifluoromethyl group at C-3' on such nucleoside derivatives appears to confer increased chemical stability toward acid-catalyzed cleavage of the glycosidic bond comparatively to their parent counterparts. When evaluated for their antiviral activity in cell culture experiments, two compounds, namely, 2',3'-dideoxy-3'-C-CF3-adenosine and 2',3'-dideoxy-2',3'-didehydro-3'-C-CF3-cytidine exhibited moderate anti-HBV activity with EC50 values of 10 and 5 microM, respectively.

Adenosine↗

PubMed2002

A new class of acyclic nucleoside phosphonates: synthesis and biological activity of 9-[[(phosphonomethyl)aziridin-1-yl]methyl]guanine (PMAMG) and analogues.

A new class of acyclic nucleoside phosphonates PMAMG, PMAMA, PMAMC, and PMAMT (compounds 1, 2, 3 and 4) have been synthesized and tested in vitro against a wide variety of viruses, fungi and bacteria. PMAMG (1) was synthesized by the alkylation reaction of acetylguanine with the phosphonate side-chain, diisopropyl [[2-(bromomethyl)aziridin-1-yl]]methylphosphonate (9), followed by deesterification reaction in the presence of TMSBr. In similar way, PMAMA, PMAMC, and PMAMT were prepared.

Alkylation↗