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Microtubule-targeting agents (MTA) have enjoyed significant clinical success for decades. However, several mechanisms may cause inactivation of such drugs, leading to acquired resistance in patients treated with them. Therefore, drugs containing a stilbene-like skeleton and possessing dual inhibitory activity may provide a new and differentiated treatment for patients to overcome challenging acquired resistance. A new compound (16c) displays promising anticancer activity with GI 50 of 22 ± 2 and 12 ± 0.1 nM in vincristine-resistant nasopharyngeal (KB-Vin) cancer cells and etoposide-resistant nasopharyngeal (KB-7D) cancer cells and is better than vincristine, etoposide, ABT-751, and MS-275. A mechanistic study revealed that 16c interferes with the cell cycle distribution and induces cell cycle arrest at the G2/M phase and severe mitotic spindle defects followed by apoptosis. In addition, it produces much more significant cytotoxicity than vincristine and etoposide in the corresponding resistant cells, indicating that it may be a promising candidate to overcome drug resistance in cancer cells. Compound 16c also displays inhibitory activity against HDAC 1 and HDAC 2 with IC 50 values of 1.07 μM, and 1.47 μM, respectively. These findings may lead to a new type of structural motif for future development of drugs that could overcome acquired resistance to MTAs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier Masson SAS.)

This study reports the synthesis of a series of 2-aroylisoindoline hydroxamic acids employing N-benzyl, long alkyl chain and acrylamide units as diverse linkers. In-vitro studies led to the identification of N-benzyl linker-bearing compound (10) and long chain linker-containing compound (17) as dual selective HDAC6/HSP90 inhibitors. Compound 17 displays potent inhibition of HDAC6 isoform (IC 50  = 4.3 nM) and HSP90a inhibition (IC 50  = 46.8 nM) along with substantial cell growth inhibitory effects with GI 50  = 0.76 μM (lung A549) and GI 50  = 0.52 μM (lung EGFR resistant H1975). Compound 10 displays potent antiproliferative activity against lung A549 (GI 50  = 0.37 μM) and lung H1975 cell lines (GI 50  = 0.13 μM) mediated through selective HDAC6 inhibition (IC 50  = 33.3 nM) and HSP90 inhibition (IC 50  = 66 nM). In addition, compound 17 also modulated the expression of signatory biomarkers associated with HDAC6 and HSP90 inhibition. In the in vivo efficacy evaluation in human H1975 xenografts, 17 induced slightly remarkable suppression of tumor growth both in monotherapy as well as the combination therapy with afatinib (20 mg/kg). Moreover, compound 17 could effectively reduce programmed death-ligand 1 (PD-L1) expression in IFN-γ treated lung H1975 cells in a dose dependent manner suggesting that dual inhibition of HDAC6 and HSP90 can modulate immunosuppressive ability of tumor area., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier Masson SAS.)

A series of C6-substituted N-hydroxy-2-quinolineacrylamides (3-15), with four types of bridging groups have been synthesized. Most of these compounds exhibit antiproliferative activity against A549 and HCT116 cells and Western blot analysis revealed that they are able to inhibit HDAC. Measurement of the HDAC isoform activity of ether-containing compounds showed that compound 9 has distinct HDAC6 selectivity, more than 300-fold over other isoforms. This paper describes the development of 6-aryloxy-N-hydroxy-2-quinolineacrylamides as potential HDAC6 inhibitors., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Novel dual inhibitors of histone deacetylase (HDAC) and heat-shock protein 90 (HSP90) are synthesized and evaluated. These compounds are endowed with potent HDAC and HSP90 inhibitory activities with IC 50 values in nanomolar range with Compound 20 (HDAC IC 50  = 194 nM; HSP90α IC 50  = 153 nM) and compound 26 (HDAC IC 50  = 360 nM; HSP90α IC 50  = 77 nM) displaying most potent HDAC and HSP90α inhibitory activities. Both of these compounds induce HSP70 expression and down regulate HSP90 client proteins which play important roles in the regulation of survival and invasiveness in cancer cells. In addition, compounds 20 and 26 induce acetylation of α-tubulin and histone H3. Significantly, compounds 20 and 26 could effectively reduce programmed death-ligand 1 (PD-L1) expression in IFN-γ treated lung H1975 cells in a dose dependent manner. These findings suggest that dual inhibition of HDAC and HSP90 that can modulate immunosuppressive ability of tumor area may provide a better therapeutic strategy for cancer treatment in the future., (Copyright © 2019. Published by Elsevier Masson SAS.)

The study is focused on the design and synthesis of amide tethered quinoline-resorcinol hybrid constructs as a new class of HSP90 inhibitor. In-vitro studies of the synthetic compounds led to the identification of compound 11, which possesses potent cell growth inhibitory effects against HCT116, Hep3B and PC-3 cell lines, exerted through HSP90 inhibition. Compound 11 triggers degradation of HSP90 client proteins along with concomitant induction of HSP70, demonstrates apoptosis inducing ability and causes G2M phase cell cycle arrest in PC-3 cells. Molecular modeling was used to dock compound 11 into the HSP90 active site and key interactions with the amino acid residues of the HSP90 chaperone protein were determined., (Copyright © 2019. Published by Elsevier Inc.)

The cantharidinimide derivatives, 5a-h, including sulfanilamides containing pyrimidyl, pyrazinyl, hydrogen, thiazolyl, and oxazolyl groups were synthesized. Modification of cantharidinimide by means of the reaction of activated aziridine ring opening led to the discovery of a novel class of antitumor compounds. The analogues 10i-k, 11l-n, 12o-p, and 16q-s were obtained from treating cantharidinimide 6 and analogues (7, 8, and 13) with activated aziridines, which produced a series of ring-opened products including normal and abnormal types. Some of these compounds showed cytotoxic effects in vitro against HL-60, Hep3B, MCF7, and MDA-MB-231 cancer cells. The most potent cytostatic compound, N-cantharidinimido-sulfamethazine (5a), exhibited anti-HL-60 and anti-Hep3B cell activities. Two compounds 5g and 5h displayed slight effects on the Hep3B cell line, while the other compounds produced no response in these four cell lines.

In this study, we investigated the antitumor activity of a novel coumarin derivative, 5,7-dihydroxy-4-methyl-6-(3-methylbutanoyl)-coumarin (DMAC), on colorectal carcinoma. DMAC treatment resulted in substantial proapoptotic activity against colon cancer HCT116 and LoVo cells. Induction of apoptotic characteristics, including cellular shrinkage, chromatin condensation, and Annexin V detection, was observed following DMAC treatment. Mechanistically, we observed that DMAC elicited induction of proteolytic cascade activation including cleavage of caspase-3 and poly ADP-ribose polymerase (PARP) expression and loss of the antiapoptotic proteins, Mcl-1 and Bcl-XL, accompanied by an increase in expression of the proapoptotic protein, Bak. In addition, suppressing c-Jun N-terminal protein kinase (JNK), but not extracellular-regulated protein kinase (ERK) or p38, substantially diminished DMAC-induced cell death and caspase-3 and PARP cleavage. However, pretreatment with antioxidants, including N-acetyl-l-cysteine (NAC) and diphenylene iodonium (DPI), failed to protect against DMAC-elicited apoptosis. Pretreatment with the JNK inhibitor, SP600125, suppressed DMAC-induced JNK phosphorylation, which was accompanied by a reversal of Bcl-XL expression. Moreover, combining DMAC treatment with the conventional anticancer drugs, 5-FU and CPT-11, considerably enhanced their therapeutic efficacies. Structural-activity relationship analyses further revealed that an alkylation substitution at position 6 of the coumarin ring was critical for inducing apoptosis, and the phenyl group at position 4 might have enhanced its bioactivity. Our data showed that DMAC can be used as part of a promising strategy to enhance therapeutic efficacies, and could be used to develop an approach for structure-based drug design for cancer treatment., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

A novel series of the biheterocycles-based compounds with core structure distinguished from combretastatin A-4 (1) and colchicine (5) have been synthesized and evaluated as potent anti-mitotic agents. Compound 1-(4'-Indolyl and 6'-quinolinyl)-4,5,6-trimethoxyindoles 13 and 19 showed substantial anti-proliferative activity against various human cancer cell lines, regardless to the tissue origin and the expression of multiple-drug resistance MDR1, with a mean IC(50) value of 38 and 24 nM respectively. Compound 13 (IC(50) = 1.7 μM) also exhibited similar anti-tubulin activities to 1 (IC(50) = 1.8 μM) and displayed strong binding property to the colchicine binding site on the microtubules. Computational modeling analysis revealed that the binding mechanism of compound 13 is similar to that of CA4., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

Background: There are some limitations of standard chemotherapy for acute leukemia. Vincristine and doxorubicin are commonly used for acute leukemia, but they may induce serious side effects such as cardiomyopathy and neurotoxicity. Furthermore, chemotherapy resistance occurs more and more frequently. Therefore, effective treatment strategies are needed. Histone deacetylase 6 inhibition is considered as a potential therapeutic strategy for acute leukemia, since it is observed that HDAC6 is overexpressed in acute leukemia and regulates tumor survival. Combination therapy for cancer is used to minimize adverse drug effects, reduce drug dosage, enhance efficacy, and prevent drug resistance. In order to improve efficacy of chemotherapy agents of acute leukemia, this study will investigate the effects of combination MPT0G211, a novel histone deacetylase 6 inhibitor, with doxorubicin or vincristine on human acute leukemia cells. Results: MPT0G211 combined with doxorubicin induces DNA damage response on human acute myeloid leukemia cells. MPT0G211 can additionally increase Ku70 acetylation and release BAX to mitochondria. Ectopic expression of HDAC6 successively reversed the apoptosis triggered by the combined treatment. Moreover, co-treatment of MPT0G211 and vincristine may alter microtubule dynamics, triggering acute lymphoblastic leukemia cells arrest in mitotic phase followed by induction of the apoptotic pathway. Finally, MPT0G211 plus doxorubicin or vincristine can significantly improve the tumor growth delay in a tumor xenograft model. Conclusions: Collectively, our data highlighted that MPT0G211 in combination with chemotherapy drugs has significant anticancer activity, suggesting a novel strategy for the treatment of acute leukemia. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of 32 tricyclic sulfamates as STS irreversible inhibitors. • SAR studies revealed that adjacent halogen-bearing phenyl gave the best inhibition. • 19 m , 19v , and 19w , had K I of 0.02 to 0.11 nM against STS. • Cellular potency is significant correlated with covalent kinetics (k inact/ K I). Steroid sulfatase inhibitors block the local production of estrogenic steroids and are attractive agents for the treatment of estrogen-dependent cancers. Inspiration of coumarin-based inhibitors, we synthesized thirty-two 5-oxa-1,2,3,4-tetrahydro-2H-chromeno-(3,4-c)pyridin-8-yl sulfamates , focusing on the substitution derivatives on the adjacent phenyl ring and evaluated their abilities to block STS from human placenta and MCF-7 cells. SAR analysis revealed that the incorporation of chlorine at either meta and/or para position of the adjacent phenyl ring of the tricyclic skeleton enhanced STS inhibition. Di-substitutions at the adjacent phenyl ring were superior to mono and tri-substitutions. Further kinetic analysis of these compounds revealed that chloride-bearing compounds, such as 19 m , 19v , and 19w , had K I of 0.02 to 0.11 nM and k inact / K I ratios of 8.8–17.5 nM-1min-1, a parameter indicated for the efficiency of irreversible inhibition. We also used the docking model to illustrate the difference in STS inhibitory potency of compounds. Finally, the safety and anti-cancer activity of selected compounds 19 m , 19v , and 19w were also studied, showing the results of low cytotoxicity on NHDF cell line and being more potent than irosustat on ZR-75–1 cell, which was a hormone-dependent cancer cell line with high STS expression. [ABSTRACT FROM AUTHOR]

A series of thiochromeno[2,3- c ]quinolin-12-one derivatives with various substitutions were synthesized and evaluated as topoisomerase (Topo) inhibitors. Six (8 , 10 , 12 , 14 , 19 , and 26) of 23 compounds showed strong inhibitory activities against Topo-mediated DNA relaxation and proliferation of five human cell lines including breast (MDA-MB-231, MDA-MB-468 and MCF7), colorectal (HCT116) and non-small cell lung (H1299) cancers. Among these, compounds 14 and 26 exhibited full inhibitory activities against Topo I at 3 μM and Topo IIα at 1 μM. Cancer cells treated with 26 accumulated DNA damage and were arrested at the G 2 /M phase. With time, cells proceeded to apoptosis, as revealed by increased amounts of cells with fragmented DNA and cleavage of caspase-8 and -9. In contrast, normal breast epithelial cells showed low sensitivity to 26. Taken together, our study identifies 26 as a potent Topo dual-inhibitor with low toxicity to normal cells, and elucidates that the terminal amino group of N -2-aminoethylamino or N -3-aminopropylamino at the 6th position and 8,10-di-halogen substituents on thiochromeno[2,3- c ]quinolin-12-one are critical for the Topo-inhibiting and cancer-killing activities. Image 1 • Six compounds identified as dual Topo inhibitors. • 26 exhibits the highest toxicity in five cancer cell lines but is less toxic in normal breast epithelial cells. • 26 traps Topo I and IIα on chromatin and suppresses their activities. • 26 triggers DNA damage, cell-cycle arrest at the G 2 /M phase, followed by apoptosis. [ABSTRACT FROM AUTHOR]