miR-128 has been associated with cancer, particularly with leukemia. In particular, this miR has been described, together with other miRs, to allow the discrimination between AML (acute myeloid ...leukemia) and ALL (acute lymphoblastic leukemia). In addition, miR-128 is included in miR signatures which not only allow characterizing a particular subtype of AML but are also associated with worse clinical outcome in a subgroup of patients with high-risk molecular features of AML. Nevertheless, all the published studies are based on data from expression arrays and no functional studies have been performed. Therefore, in order to further understand the role of miR-128 in AML cells and in their response to some chemotherapy, overexpression of miR-128 was achieved with miR-mimics in an AML cell line (HL-60). This resulted in decreased cellular viability and increased sensitization to both etoposide and doxorubicin. Overexpression of miR-128 increased programmed cell death but had no effect on cell cycle profile, 1 apoptosis or autophagy, as no alterations were observed in the protein levels of PARP, pro-caspase-3, Vps34, Beclin-1 or LC3-II. In addition, miR-128 overexpression increased the levels of DNA damage, as could be concluded by an increase in the comet's tail intensity in the comet assay, an increase in the number of DNA repair foci stained with either γ-H2AX or 53BP1 proteins, and an increase in the levels of these two proteins (observed by Western blot). To the best of our knowledge, this is the first association of miR-128 with DNA damage in a leukemia context.
The virtual screening of a library of chalcone derivatives led us to the identification of potential new MDM2 ligands. The chalcones with the best docking scores obeying the Lipinski rule of five ...were subsequently prepared by base-catalyzed aldol reactions. The activity of these compounds as inhibitors of p53–MDM2 interaction was investigated using a yeast-based screening assay. Using this approach two chalcones (3 and 4) were identified as putative small molecule inhibitors of p53–MDM2 interaction. The activity of both chalcones was further investigated in a panel of human tumor cells. Chalcones 3 and 4 revealed a pronounced tumor cell growth inhibitory effect on tumor cell lines. Additionally, chalcone 4 caused alterations in the cell cycle profile, induced apoptosis and increased the levels of p53, p21 and PUMA proteins in NCI-H460 cells. Computational docking studies allowed to predict that, like nutlin-3A (a well-known small-molecule inhibitor of p53–MDM2 interaction), chalcones 3 and 4 bind to the p53-binding site of MDM2. The results here presented will be valuable for the structure-based design of novel and potent p53–MDM2 inhibitors.
Antiapoptotic genes such as bcl-2 or xIAP may be responsible for resistance to apoptosis induced by cytotoxic drugs. The aim of this study was to investigate if downregulation of bcl-2 or xIAP by RNA ...interference (RNAi) would sensitize MCF-7 cells to etoposide and doxorubicin. FITC-siRNAs uptake was verified by fluorescence microscopy and downregulation of Bcl-2 or XIAP was confirmed by Western Blotting. Both siRNAs reduced the number of viable cells and increased cellular apoptosis. Treatment with siRNAs followed by treatment with etoposide or doxorubicin further reduced the number of viable cells, when compared to either of the treatments alone. Therefore, downregulation of bcl-2 or xIAP by RNAi enhances the effects of etoposide and doxorubicin.
Marine organisms are a prolific source of drug leads in a variety of therapeutic areas. In the last few years, biomedical, pharmaceutical and nutraceutical industries have shown growing interest in ...novel compounds from marine organisms, including macroalgae. Cystoseira is a genus of Phaeophyceae (Fucales) macroalgae known to contain bioactive compounds. Organic extracts (hexane, diethyl ether, ethyl acetate and methanol extracts) from three Cystoseira species (C. humilis, C. tamariscifolia and C. usneoides) were evaluated for their total phenolic content, radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals, and antiproliferative activity against a human hepatocarcinoma cell line (HepG2 cells). C. tamariscifolia had the highest TPC and RSA. The hexane extract of C. tamariscifolia (CTH) had the highest cytotoxic activity (IC50 = 2.31 µg/mL), and was further tested in four human tumor (cervical adenocarcinoma HeLa; gastric adenocarcinoma AGS; colorectal adenocarcinoma HCT-15; neuroblastoma SH-SY5Y), and two non-tumor (murine bone marrow stroma S17 and human umbilical vein endothelial HUVEC) cell lines in order to determine its selectivity. CTH strongly reduced viability of all tumor cell lines, especially of HepG2 cells. Cytotoxicity was particularly selective for the latter cells with a selectivity index = 12.6 as compared to non-tumor cells. Incubation with CTH led to a 2-fold decrease of HepG2 cell proliferation as shown by the bromodeoxyuridine (BrdU) incorporation assay. CTH-treated HepG2 cells presented also pro-apoptotic features, such as increased Annexin V/propidium iodide (PI) binding and dose-dependent morphological alterations in DAPI-stained cells. Moreover, it had a noticeable disaggregating effect on 3D multicellular tumor spheroids. Demethoxy cystoketal chromane, a derivative of the meroditerpenoid cystoketal, was identified as the active compound in CTH and was shown to display selective in vitro cytotoxicity towards HepG2 cells.
Fourteen baicalein and 3,7-dihydroxyflavone derivatives were synthesized and evaluated for their inhibitory activity against the in vitro growth of three human tumor cell lines. The synthetic ...approaches were based on the reaction with prenyl or geranyl bromide in alkaline medium, followed by cyclization of the respective monoprenylated derivative. Dihydropyranoflavonoids were also obtained by one-pot synthesis, using Montmorillonite K10 clay as catalyst combined with microwave irradiation. In vitro screening of the compounds for cell growth inhibitory activity revealed that the presence of one geranyl group was associated with a remarkable increase in the inhibitory activity. Moreover, for the 3,7-dihydroxyflavone derivatives a marked increase in growth inhibitory effect was also observed for compounds with furan and pyran fused rings. The most active compounds were also studied regarding their effect on cell cycle profile and induction of apoptosis. Overall the results point to the relevant role of the prenylation of flavone scaffold in the growth inhibitory activity of cancer cells.
Fourteen baicalein (1) and 3,7-dihydroxyflavone (2) derivatives were synthesized and evaluated for their inhibitory activity against the in vitro growth of three human tumor cell lines, being the most active compounds also studied regarding their effect on cell cycle profile and induction of apoptosis. Display omitted
► Fourteen prenylated flavonoids were synthesized, twelve of them for the first time. ► Compounds 6, 15, 16 clearly demonstrated the best results in cell growth inhibition. ► Compounds 3 and 6 caused the highest increases in the % of cells in G1 phase. ► Compound 6 revealed a significant increase in the levels of apoptosis.
Some polyamine derivatives, namely the bisnaphthalimidopropyl polyamines (BNIPPs) may have potential as anticancer drugs. Indeed, previous work from some of us had shown that the ability of these ...molecules to bind to DNA may contribute to their cytotoxicity. However, their precise mode of action has not been fully understood. In the present work, we report for the first time the effect of the previously synthesised compounds, BNIPDaCHM and NPA, together with a new BNIP derivative (BNIP-3,4-DaDPM) in the in vitro growth of a non-small cell lung cancer cell line (NCI-H460). In addition, for the most potent compound (BNIPDaCHM), its activity as sirtuin inhibitor was investigated in vitro and further confirmed in silico. Results in the NCI-H460 cells showed that, from the compounds tested, BNIPDaCHM was the most potent (GI50 of 1.3 μM). In addition, a concentration-dependent alteration in the normal NCI-H460 cell cycle profile was observed following treatment with BNIPDaCHM as well as an increase in the sub-G1 peak (suggestive of apoptotis). This effect was further supported by Annexin V/PI staining and by analysing the expression of proteins related to apoptosis (cleaved PARP and Caspase-3) by Western blot. It was also observed that BNIPDaCHM inhibited the activity of SIRT2 in vitro, but not of SIRT1. Accordingly, this compound also caused a small increase in tubulin acetylation in NCI-H460 cells. To determine the binding potential of BNIPDaCHM on hSIRT2 and to further validate its inhibitory action, in silico docking studies were carried out, which revealed that BNIPDaCHM is composed of an entirely new SIRT2- inhibiting structural scaffold. In conclusion, this study indicates that BNIP derivatives with a novel structural backbone, such as BNIPDaCHM, may have potential as building blocks for novel antitumour agents which might selectively bind to hSIRT-2.
A wide variety of new bi(hetero)aryl derivatives of the thieno3,2-
bpyridine skeleton was obtained in high to excellent yields (65–91%) by Suzuki–Miyaura cross-coupling of the methyl ...3-amino-6-bromothieno3,2-
bpyridine-2-carboxylate, recently reported by us, with aryl or heteroaryl pinacolboranes or potassium trifluoroborates.
The coupling products obtained were evaluated for their growth inhibitory effect on three human tumor cell lines, representing different tumor models, MCF-7 (breast adenocarcinoma), A375-C5 (melanoma) and NCI-H460 (non-small cell lung cancer). Some of the compounds showed an interesting activity against the tested cell lines, with GI
50 values in the μM range, and it was possible to establish some structure–activity relationships (SARs). Several compounds presented GI
50 values below 15 μM, particularly a bithiophene and an
o-aniline thienopyridine derivative. The first presented selectivity for MCF-7 and NCI-H460 cell lines, with very low GI
50 values (0.7–1.0 μM), while the latter was active against the three cell lines tested in this study, also presenting very low GI
50 values (2.5–4.2 μM). The effect of these two compounds on cell cycle progression was analyzed in the NCI-H460 cell line. Results showed that both compounds interfered with the normal cell cycle distribution.
Bi(hetero)aryl derivatives of the thieno3,2-
bpyridine were obtained by Suzuki–Miyaura cross-coupling of the methyl 3-amino-6-bromothieno3,2-
bpyridine-2-carboxylate with aryl or heteroaryl pinacolborane esters or potassium trifluoroborates, in good to excellent yields. The coupling products were evaluated for their growth inhibitory effect on three representative human tumor cell lines. For the two most promising compounds, cell cycle analysis was performed in one of the cell lines in study.
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One possible approach to overcome solubility complications and enhance the biological activity of drugs is their incorporation into drug delivery systems. Within this scope, several nanosphere and ...nanocapsule formulations of a new inhibitor of p53–MDM2 interaction (xanthone 1) were developed and their physicochemical properties analyzed. Through the investigation of the effect of several empty nanoparticles on the growth of MCF-7 cells, it was possible to observe that four out of five formulations were cytotoxic and that some correlations between the toxic potential of these polymeric nanoparticles and their properties/composition could be extrapolated. One empty formulation of nanocapsules developed by emulsification/solvent evaporation and containing PLGA, PVA and Mygliol® 812 was found to be noncytotoxic to this cell line. The corresponding compound 1-loaded nanocapsules showed an incorporation efficiency of 77% and revealed to be more potent than the free drug against cell growth inhibition, which may be related to the enhancement in its intracellular delivery. In an integrative study, the intracellular uptake of nanocapsules was confirmed using fluorescent 6-coumarin and well as compound 1 release from nanocapsules. Overall, it was possible to enhance the effect of the hit inhibitor of p53–MDM2 interaction through the development of suitable noncytotoxic polymeric nanoparticles.
The benzopyran and dihydrobenzopyran moieties can be considered as “privileged motifs” in drug discovery being good platforms for the search of new bioactive compounds. These moieties are commonly ...found fused to the xanthonic scaffold belonging to the biologically important family of the generally designated prenylated xanthones. Several pyranoxanthones have shown promising antitumor activity and since most of them are from natural origin, the biosynthetic pathway only allows a particular pattern of substitution which limits their structural diversity and renders any broad structure–activity study hard to be established. Accordingly, with the aim of rationalizing the importance of the fused ring orientation and oxygenation pattern in pyranoxanthones, this study describes the synthesis of 14 new pyranoxanthones and evaluation of their cell growth inhibitory activity in four human tumor cell lines as well as their lipophilicity in two membrane models. This systematic approach allowed establishing structure–activity and structure–lipophilicity relationships for the obtained compounds in combination with 6 previously described compounds. From this work an angular pyranoxanthone scaffold emerged as particularly promising, presenting a potent cell growth inhibitory activity and suitable drug-like lipophilicity.
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•21 pyranoxanthones were synthesized using different synthetic approaches.•Their growth inhibitory effect was evaluated on four human tumor cell lines.•Several pyranoxanthones were active in the HL-60 tumor cell line.•The lipophilicity of the pyranoxanthones was evaluated in two membrane models.•Compound 32 showed to be particularly promising as potential antitumor agent.
New fluorinated and methoxylated di(hetero)arylethers and di(hetero)arylamines were prepared functionalizing the 7-position of the thieno3,2-bpyridine, using copper (C–O) or palladium (C–N) catalyzed ...couplings, respectively, of the 7-bromothieno3,2-bpyridine, also prepared, with ortho, meta and para fluoro or methoxy phenols and anilines. The compounds obtained were evaluated for their growth inhibitory activity on the human tumor cell lines MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer), HCT15 (colon carcinoma), HepG2 (hepatocellular carcinoma) and HeLa (cervical carcinoma). The most active compounds, a di(hetero)arylether with a methoxy group in the meta position relative to the ether function and two di(hetero)arylamines with a methoxy group either in the ortho or in the meta position relative to the NH, were further tested at their GI50 concentrations on NCI-H460 cells causing pronounced alterations in the cell cycle profile and a strong and significant increase in the programmed death of these cells. The fluorinated and the other methoxylated compounds did not show important activity, presenting high GI50 values in all the cell lines tested. Furthermore, the hepatotoxicity of the compounds was assessed using porcine liver primary cells (PLP2), established by some of us. Results showed that one of the most active compounds was not toxic to the non-tumor cells at their GI50 concentrations showing to be the most promising as antitumoral.
Di(hetero)arylethers and di(hetero)arylamines were obtained by metal-catalyzed-couplings. Some methoxy derivatives were the most potent against human tumor cell lines, and alter the cell cycle and increase apoptosis on NCI-H460 cells. Display omitted
•Di(hetero)arylethers and amines in the thieno3,2-bpyridine series were prepared.•Some methoxy compounds inhibited significantly the growth of human tumor cell lines.•These altered the NCI-H460 cell cycle and increased the programmed death of cells.•One of them was not toxic to non-tumor cells at the GI50 concentrations.
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