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Purpose: Alteration in cell death is a hallmark of cancer. A functional role regulating survival, apoptosis, and necroptosis has been attributed to RIP1/3 complexes.Experimental Design: We have investigated the role of RIP1 and the effects of MC2494 in cell death induction, using different methods as flow cytometry, transcriptome analysis, immunoprecipitation, enzymatic assays, transfections, mutagenesis, and in vivo studies with different mice models.Results: Here, we show that RIP1 is highly expressed in cancer, and we define a novel RIP1/3–SIRT1/2–HAT1/4 complex. Mass spectrometry identified five acetylations in the kinase and death domain of RIP1. The novel characterized pan-SIRT inhibitor, MC2494, increases RIP1 acetylation at two additional sites in the death domain. Mutagenesis of the acetylated lysine decreases RIP1-dependent cell death, suggesting a role for acetylation of the RIP1 complex in cell death modulation. Accordingly, MC2494 displays tumor-selective potential in vitro, in leukemic blasts ex vivo, and in vivo in both xenograft and allograft cancer models. Mechanistically, MC2494 induces bona fide tumor-restricted acetylated RIP1/caspase-8–mediated apoptosis. Excitingly, MC2494 displays tumor-preventive activity by blocking 7,12-dimethylbenz(α)anthracene–induced mammary gland hyperproliferation in vivo.Conclusions: These preventive features might prove useful in patients who may benefit from a recurrence-preventive approach with low toxicity during follow-up phases and in cases of established cancer predisposition. Thus, targeting the newly identified RIP1 complex may represent an attractive novel paradigm in cancer treatment and prevention. Clin Cancer Res; 24(12); 2886–900. ©2018 AACR.

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Purpose: Alteration in cell death is a hallmark of cancer. A functional role regulating survival, apoptosis, and necroptosis has been attributed to RIP1/3 complexes. Experimental Design: We have investigated the role of RIP1 and the effects of MC2494 in cell death induction, using different methods as flow cytometry, transcriptome analysis, immunoprecipitation, enzymatic assays, transfections, mutagenesis, and in vivo studies with different mice models. Results: Here, we show that RIP1 is highly expressed in cancer, and we define a novel RIP1/3–SIRT1/2–HAT1/4 complex. Mass spectrometry identified five acetylations in the kinase and death domain of RIP1. The novel characterized pan-SIRT inhibitor, MC2494, increases RIP1 acetylation at two additional sites in the death domain. Mutagenesis of the acetylated lysine decreases RIP1-dependent cell death, suggesting a role for acetylation of the RIP1 complex in cell death modulation. Accordingly, MC2494 displays tumor-selective potential in vitro, in leukemic blasts ex vivo, and in vivo in both xenograft and allograft cancer models. Mechanistically, MC2494 induces bona fide tumor-restricted acetylated RIP1/caspase-8–mediated apoptosis. Excitingly, MC2494 displays tumor-preventive activity by blocking 7,12-dimethylbenz(α)anthracene–induced mammary gland hyperproliferation in vivo. Conclusions: These preventive features might prove useful in patients who may benefit from a recurrence-preventive approach with low toxicity during follow-up phases and in cases of established cancer predisposition. Thus, targeting the newly identified RIP1 complex may represent an attractive novel paradigm in cancer treatment and prevention. Clin Cancer Res; 24(12); 2886–900. ©2018 AACR.

A comparison of the effects of the 6-(2-chloro-6-fluorobenzyl)-2-(alkylthio)pyrimidin-4(3H)-ones (2-Cl-6-F-S-DABOs) 7-12 and the related 6-(2,6-difluorobenzyl) counterparts 13-15 in HIV-1 infected cells and in the HIV-1 reverse transcriptase (RT) assays is here described. The new 2-Cl-6-F-S-DABOs showed up to picomolar activity against wt HIV-1. Against clinically relevant HIV-1 mutants and in enzyme assays, the simultaneous C5(methyl)/C6(methyl/ethyl) substitution in the 2-Cl-6-F- and 2,6-F2-benzyl series furnished compounds with the highest, wide-spectrum inhibitory activity against HIV-1. Three representative 2-Cl-6-F-S-DABOs carrying two (9c, 10c) or one (10a) stereogenic centers were resolved into their individual stereoisomers and showed a significant diastereo- and enantioselectivity in HIV-1 inhibition, the highest antiviral activity well correlating with the R absolute configuration to the stereogenic center of the C6-benzylic position in both cellular and enzymatic tests. Application of previously reported COMBINEr protocol on 9c and 10c confirmed the influence of the stereogenic centers on their binding modes in the HIV-1 RT.

International audience; Chemical manipulations performed on the histone H3 lysine 9 methyltransferases (G9a/GLP) inhibitor BIX-01294 afforded novel desmethoxyquinazolines able to inhibit the DNA methyltransferase DNMT3A at low micromolar levels without any significant inhibition of DNMT1 and G9a. In KG-1 cells such compounds, when tested at sub-toxic doses, induced the luciferase re-expression in a stable construct controlled by a cytomegalovirus (CMV) promoter silenced by methylation (CMV-luc assay). Finally, in human lymphoma U-937 and RAJI cells, the N-(1-benzylpiperidin-4-yl)-2-(4-phenylpiperazin-1-yl)quinazolin-4-amine induced the highest proliferation arrest and cell death induction starting from 10 µM, in agreement with its DNMT3A inhibitory potency.

"In this report we describe the synthesis and biological characterization of two series of sirtuins' inhibitors (SIRTi), designed as simplification products of the previously reported SIRT1-selective inhibitor MC2141 (4). In the first series (5a-t) we report a number of 2-substituted-1,2-dihydrobenzo[f]chromen-3-ones with a marked selectivity for the inhibition of SIRT2 over SIRT1. Some of such derivatives showed also high pro-apoptotic (5i and 5l) and\/or cytodifferentiating (5d, 5i, and 5o) properties in a human leukemia cell line (U937). The second group of SIRTi (6a-q) is characterized by some analogues of cambinol (3), a well known SIRTi active against the Burkitt lymphoma. Such compounds, differently from the unselective prototype, are endowed with a selective inhibition of SIRT1 over SIRT2, and, in some cases (6j, 6k, and 6q), are more efficient than 3 to induce apoptosis in U937 cells."

Here, we describe a novel small series of non-nucleoside reverse transcriptase inhibitors (NNRTIs) that combine peculiar structural features of diarylpyrimidines (DAPYs) and dihydro-alkoxy-benzyl-oxopyrimidines (DABOs). These DAPY-DABO hybrids (1-4) showed a characteristic SAR profile and a nanomolar anti-HIV-1 activity at both enzymatic and cellular level. In particular, the two compounds 4d and 2d, with a (sub)nanomolar activity against wild-type and clinically relevant HIV-1 mutant strains, were selected as lead compounds for next optimization studies.

The 6-((7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)thio)hexan-1-ol (NBDHEX, 1), a "suicide inhibitor" of the glutathione-S-transferase GSTP1-1, showed pro-apoptotic properties in tumor cells, but in vivo studies were limited by poor bioavailability and high affinity towards GSTM2-2, expressed in many non-cancerous tissues. Here we describe the synthesis and biological characterization of new 1 analogs (2-40), in which the hydroxyhexyl portion at the C4-sulfur atom has been replaced with phenyl-containing moieties as well as substituted alkyl chains. Some of the new compounds displayed 10-100 times increased water-solubility (8, 11, 17, 26-28, 34, 35), and most of them showed higher GSTP1-1 selectivity (2-20, 23-26, 31-33, 35) than 1. The presence of a phenyl ring with polar substituents is in general associated, with some exceptions (23, 24) to low cytotoxicity in osteosarcoma U-2OS cells. Differently, some alkyl derivatives possess cytotoxicity comparable (26, 34, 35) or higher (30, 32) than 1. Among the novel compounds, selected ones (26, 27, 34, and 35) deserve further investigation for their anticancer potential.

Starting from a yeast phenotypic screening performed on 21 compounds, we described the identification of two small molecules (9 and 18) able to significantly reduce the S. cerevisiae cell growth, thus miming the effect of GCN5 deletion mutant. Tested on a GCN5-dependent gene transcription assay, compounds 9 and 18 gave a high reduction of the reporter activity. In S. cerevisiae histone H3 terminal tails assay, the H3 acetylation levels were highly reduced by treatment with 0.6-1 mM 9, while 18 was effective only at 1.5 mM. In human leukemia U937 cell line, at 1 mM 9 and 18 showed effects on cell cycle (arrest in G1 phase, 9), apoptosis (9), and granulocytic differentiation (18). When tested on U937 cell nuclear extracts to evaluate their histone acetyltransferase (HAT) inhibitory action, both compounds were able to reduce the enzyme activity when used at 500 microM. Another quinoline, compound 22, was synthesized with the aim to improve the activity observed with 9 and 18. Tested in the HAT assay, 22 was able to reduce the HAT catalytic action at 50 and 25 microM, thereby being comparable to anacardic acid, curcumin, and MB-3 used as references. Finally, in U937 cells, compounds 9 and 18 used at 2.5 mM were able to reduce the extent of the acetylation levels of histone H3 (9) and alpha-tubulin (9 and 18). In the same assay, 22 at lower concentration (100 microM) showed the same hypoacetylating effects with both histone and non-histone substrates.

Chemical changes performed on 1a (sirtinol) led to a series of SIRT1/2 inhibitors, in some cases more potent than 1a mainly against SIRT1. Tested in human leukemia U937 cells, the benzamide and anilide derivatives 1b, 1c, 2b, and 2c as well as the 4-(2-phenylpropyl)thioanalogue 4c showed huge apoptosis induction, while some sulfinyl and sulfonyl derivatives (5b, 5c, and 6a-c) were highly efficient in granulocytic differentiation. When assayed in human leukemia MOLT4 as well as in human breast MDA-MB-231 and colon RKO cancer cell lines, the anilide 2b (salermide) and the phenylpropylthio analogue 4b emerged as the most potent antiproliferative agents. Tested on colorectal carcinoma and glioblastoma multiforme cancer stem cells (CSCs) from patients, 2b was particularly potent against colorectal carcinoma CSCs, while 4b, 6a, and the SIRT2-selective inhibitor AGK-2 showed the highest effect against glioblastoma multiforme CSCs. Such compounds will be further explored for their broad-spectrum anticancer properties.

The single enantiomers of two pyrimidine-based HIV-1 non-nucleoside reverse transcriptase inhibitors, 1 (MC1501) and 2 (MC2082), were tested in both cellular and enzyme assays. In general, the R forms were more potent than their S counterparts and racemates and (R)-2 was more efficient than (R)-1 and the reference compounds, with some exceptions. Interestingly, (R)-2 displayed a faster binding to K103N RT with respect to WT RT, while (R)-1 showed the opposite behavior.

Inhibition of sirtuins has recently been proposed as a promising anticancer strategy. Some of the new benzodeazaoxaflavins (2a, 2b, and 2d) here reported as SIRT1/2 inhibitors were endowed with pro-apoptotic properties in human U937 leukemia cells and, most importantly, together with the prototype MC2141 (1) displayed antiproliferative effects in cancer stem cells from patients with colorectal carcinoma and glioblastoma multiforme, known to be highly tumorigenic, resistant to conventional cancer chemotherapy, and responsible, at least in part, for cancer relapse or recurrence. © 2012 American Chemical Society.

We identified a series of 4-hydroxyquinolines bearing a C1 to C15 alkyl chain at the C2 position and a carbethoxy/carboxy group at the C3 position of the quinoline nucleus (MC compounds), endowed with selective inhibitory activity against the p300/CBP HAT enzymes. Enzyme inhibition was investigated using in vitro HAT assays and by western blot analysis of cellular lysates to examine the acetylation levels of histone H3 and alpha-tubulin. When tested in U937 cells, some compounds displayed pro-apoptotic or cytodifferentiating properties.

A series of dihydro-alkylthio-benzyl-oxopyrimidines (S-DABOs) bearing a 2-aryl-2-oxoethylsulfanyl chain at pyrimidine C2, an alkyl group at C5, and a 2,6-dichloro-, 2-chloro-6-fluoro-, and 2,6-difluoro-benzyl substitution at C6 (oxophenethyl- S-DABOs, 6-8) is here described. The new compounds showed low micromolar to low nanomolar (in one case subnanomolar) inhibitory activity against wt HIV-1. Against clinically relevant HIV-1 mutants (K103N, Y181C, and Y188L) as well as in enzyme (wt and K103N, Y181I, and L100I mutated RTs) assays, compounds carrying an ethyl/ iso-propyl group at C5 and a 2,6-dichloro-/2-chloro-6-fluoro-benzyl moiety at C6 were the most potent derivatives, also characterized by low fold resistance ratio. Interestingly, the structure-activity relationship (SAR) data drawn from this DABO series are more related to HEPT than to DABO derivatives. These findings were at least in part rationalized by the description of a fair superimposition between the 6-8 and TNK-651 (a HEPT analogue) binding modes in both WT and Y181C RTs.

Following the disclosure of dihydro-alkoxy-, dihydro-alkylthio-, and dihydro-alkylamino-benzyl-oxopyrimidines (DABOs, S-DABOs, and NH-DABOs) as potent and selective anti-HIV-1 agents belonging to the non-nucleoside reverse transcriptase inhibitor (NNRTI) class, we report here the synthesis and biological evaluation of a novel series of DABOs bearing a N,N-disubstituted amino group or a cyclic amine at the pyrimidine-C2 position, a hydrogen atom or a small alkyl group at C5 and/or at the benzylic position, and the favorable 2,6-difluorobenzyl moiety at the C6 position (F2-N,N-DABOs). The new compounds were highly active up to the subnanomolar level against both wt HIV-1 and the Y181C mutant and at the submicromolar to nanomolar range against the K103N and Y188L mutant strains. Such derivatives were more potent than S-DABOs, NH-DABOs, and nevirapine and efavirenz were chosen as reference drugs. The higher inhibitor adaptability to the HIV-1 RT non-nucleoside binding site (NNBS) may account for the higher inhibitory effect exerted by the new molecules against the mutated RTs.