Targeting Glioma Stem Cells by Functional Inhibition of Dynamin 2: A Novel Treatment Strategy for Glioblastoma.

Glioma stem cells (GSCs) play major roles in drug resistance, tumour maintenance and recurrence of glioblastoma. We investigated inhibition of the GTPase dynamin 2 as a therapy for glioblastoma. Glioma cell lines and patient-derived GSCs were treated with dynamin inhibitors, Dynole 34-2 and CyDyn 4-36. We studied about cell viability, and GSC neurosphere formation in vitro and orthotopic tumour growth in vivo. Dynamin inhibition reduced glioblastoma cell line viability and suppressed neurosphere formation and migration of GSCs. Tumour growth was reduced by CyDyn 4-36 treatment. Dynamin 2 inhibition therefore represents a novel approach for stem cell-directed Glioblastoma therapy.

The Bispidinone Derivative 3,7-Bis-[2-(S)-amino-3-(1H-indol-3-yl)-propionyl]-1,5-diphenyl-3,7-diazabicyclo[3.3.1]nonan-9-one Dihydrochloride Induces an Apoptosis-Mediated Cytotoxic Effect on Pancreatic Cancer Cells In Vitro.

Pancreatic cancer (PC) is a complex, heterogeneous disease with a dismal prognosis. Current therapies have failed to improve survival outcomes, urging the need for discovery of novel targeted treatments. Bispidinone derivatives have yet to be investigated as cytotoxic agents against PC cells. The cytotoxic effect of four bispidinone derivatives (BisP1: 1,5-diphenyl-3,7-bis(2-hydroxyethyl)-3,7-diazabicyclo[3.3.1]nonan-9-one; BisP2: 3,7-bis-(2-(S)-amino-4-methylsulfanylbutyryl)-1,5-diphenyl-3,7-diazabicyclo[3.3.1]nonan-9-one dihydrochloride; BisP3: [2-{7-[2-(S)-tert-butoxycarbonylamino-3-(1H-indol-3-yl)-propionyl]-9-oxo-1,5-diphenyl-3,7-diazabicyclo[3.3.1]non-3-yl}-1-(S)-(1H-indol-3-ylmethyl)-2-oxoethyl]-carbamic acid tertbutyl ester; BisP4: 3,7-bis-[2-(S)-amino-3-(1H-indol-3-yl)-propionyl]-1,5-diphenyl-3,7-diazabicyclo[3.3.1]nonan-9-one dihydrochloride) was assessed against PC cell lines (MiaPaca-2, CFPAC-1 and BxPC-3). Cell viability was assessed using a Cell Counting Kit-8 (CCK-8) colorimetric assay, while apoptotic cell death was confirmed using fluorescence microscopy and flow cytometry. Initial viability screening revealed significant cytotoxic activity from BisP4 treatment (1 µM⁻100 µM) on all three cell lines, with IC50 values for MiaPaca-2, BxPC-3, and CFPAC-1 16.9 µM, 23.7 µM, and 36.3 µM, respectively. Cytotoxic treatment time-response (4 h, 24 h, and 48 h) revealed a 24 h treatment time was sufficient to produce a cytotoxic effect on all cell lines. Light microscopy evaluation (DAPI staining) of BisP4 treated MiaPaca-2 PC cells revealed dose-dependent characteristic apoptotic morphological changes. In addition, flow cytometry confirmed BisP4 induced apoptotic cell death induction of activated caspase-3/-7. The bispidinone derivative BisP4 induced an apoptosis-mediated cytotoxic effect on MiaPaca-2 cell lines and significant cytotoxicity on CFPAC-1 and BxPC-3 cell lines. Further investigations into the precise cellular mechanisms of action of this class of compounds are necessary for potential development into pre-clinical trials.

(Z)-2-(3,4-Dichlorophenyl)-3-(1H-Pyrrol-2-yl)Acrylonitrile Exhibits Selective Antitumor Activity in Breast Cancer Cell Lines via the Aryl Hydrocarbon Receptor Pathway.

We have previously reported the synthesis and breast cancer selectivity of (Z)-2-(3,4-dichlorophenyl)-3-(1H-pyrrol-2-yl)acrylonitrile (ANI-7) in cancer cell lines. To further evaluate the selectivity of ANI-7, we have expanded upon the initial cell line panel to now include the breast cancer cell lines (MCF7, MCF7/VP16, BT474, T47D, ZR-75-1, SKBR3, MDA-MB-468, BT20, MDA-MB-231); normal breast cells (MCF-10A); and cell lines derived from colon (HT29), ovarian (A2780), lung (H460), skin (A431), neuronal (BE2C), glial (U87, SJG2), and pancreatic (MIA) cancers. We now show that ANI-7 is up to 263-fold more potent at inhibiting the growth of breast cancer cell lines (MCF7, MCF7/VP16, BT474, T47D, ZR-75-1, SKBR3, MDA-MB-468) than normal breast cells (MCF-10A) or cell lines derived from other tumor types. Measures of growth inhibition, cell cycle analysis, morphologic assessment, Western blotting, receptor binding, gene expression, small interfering RNA technology, reporter activity, and enzyme inhibition assays were exploited to define the mechanism of action of ANI-7. In this work, we report that ANI-7 mediates its effects via the activation of the aryl hydrocarbon receptor (AhR) pathway and the subsequent induction of CYP1-metabolizing mono-oxygenases. The metabolic conversion of ANI-7 induces DNA damage, checkpoint activation, S-phase cell cycle arrest, and cell death in sensitive breast cancer cell lines. Basal expression of AhR, the AhR nuclear translocator, and the CYP1 family members do not predict for sensitivity; however, inherent expression of the phase II-metabolizing enzyme sulfur transferase 1A1 does. For the first time, we identify (Z)-2-(3,4-dichlorophenyl)-3-(1H-pyrrol-2-yl)acrylonitrile as a new AhR ligand.

Focused library development of 2-phenylacrylamides as broad spectrum cytotoxic agents.

With our lead compound (E)-3-(4-chlorophenyl)-2-(1H-pyrrole-2-carbonyl)acrylonitrile (1) inducing 50% growth inhibition of 11 cancer cell lines at 27-61 µM, potency enhancements were rapidly established through the synthesis of a series of focused compound libraries. Six highly focused libraries (46 compounds in total) were synthesised. Each library allowed the identification of a new lead compound, viz Library A identified (E)-3-(pentafluorophenyl)-2-(1H-pyrrole-2-carbonyl)acrylonitrile (11) and (E)-3-(1H-indol-3-yl)-2-(1H-pyrrole-2-carbonyl)acrylonitrile (13) as inhibitors with improved cytotoxicity. Synthesis of discrete libraries of amidoacrylamide analogues (Ar-CC(CN)-Ar✠Ar-CC(CN)-C(O)NH)-Ar) resulted in a series of analogues significantly more potent that the lead, 1. Three furan three analogues: (E)-3-(5-chlorofuran-2-yl)-2-cyano-N-(4-methoxybenzyl)acrylamide (33), (E)-3-(5-bromofuran-2-yl)-2-cyano-N-(4-methoxybenzyl)acrylamide (34) and (E)-2-cyano-3-(furan-3-yl)-N-(4-methoxybenzyl)acrylamide (37) returned broad spectrum growth inhibition (GI(50) values of 5-16 µM). Replacement of the furan moiety with simple aromatics gave an additional three analogues: (E)-2-cyano-N-(4-methoxybenzyl)-3-phenylacrylamide (39), (E)-3-(4-chlorophenyl)-2-cyano-N-(4-methoxybenzyl)acrylamide (41) and (E)-2-cyano-N-(4-methoxyphenyl)-3-(naphthalen-1-yl)acrylamide (45) with GI(50) values of 7-24 µM. The final library retained the aromatic substituents but introduced a 3,4-dichlorbenzylamine moiety to afford the 1-naphthyl substituted 52, which was the most potent broad spectrum cytotoxic analogue produced here in with an average GI(50)=8.6 µM. This represents a fivefold potency enhancement relative to 1 and a new cytotoxic scaffold suitable for further development.

Cytotoxic 2-phenyacrylnitriles, the importance of the cyanide moiety and discovery of potent broad spectrum cytotoxic agents.

We previously reported the discovery of a simple conjugated cyano pharmacophore which had led to the development of (Z)-2-(3,4-dichlorophenyl)-3-(4-nitrophenyl)acrylonitrile, as a selective inhibitor of oestrogen receptor positive (ER+ve) human breast cancer cell line, MCF-7. Further exploration though modification of the acrylonitrile and aromatic substituents has highlighted key structural components necessary for broad spectrum cytotoxicity. The acrylic acid derivates (Z)-2-(3,4-dichlorophenyl)-3-(4-nitrophenyl)acrylic acid and (Z)-2-(3,4-dichlorophenyl)-3-(4-methoxyphenyl)acrylic acid (9) were inactive; confirming the importance of the cyanide moiety. The most potent 2-phenylacrylonitriles synthesized were (Z)-2-(3,4-dichlorophenyl)-3-(1H-indol-3-yl)acrylonitrile and (Z)-2-(3,4-dichlorophenyl)-3-(1H-indol-5-yl)acrylonitrile (20) with an average GI(50) values of 1.4 and 0.53 µM respectively. Five additional (Z)-2-(3,4-dichlorophenyl)-3-(indolyl)acrylonitriles also displayed average GI(50) values of ≤8.4 µM. In the case of indole, this represents a 32-fold increase in broad spectrum cytotoxicity relative to the lead.

Synthesis and anticancer activity of a series of norcantharidin analogues.

Cantharidin (1) and norcantharidin (2) display high levels of anticancer activity against a broad range of tumour cell lines. Synthetic manipulation of norcantharidin yields (3S,3aR,4S,7R,7aS)-3-hydroxyhexahydro-4,7-epoxyisobenzofuran-1(3H)-one (3), which also displays a high level of anticancer activity against tumour cells but interestingly, shows selectivity towards HT29 (colon; GI(50) = 14 µM) and SJ-G2 (glioblastoma; GI(50) = 15 µM) cell lines. Substitution at the hydroxyl group of the cyclic lactone within (3) produces a diasteromeric pair of products that have no difference in cytotoxicity over the cell lines tested. Incorporation of an isopropyl tail at this position (16) produced the most promising compound of this series to date, with strong selectivity towards HT29 (colon; GI(50) = 19 µM) and SJ-G2 (glioblastoma; GI(50) = 21 µM) cell lines but completely void of any activity against the remaining tumour cell lines (GI(50) > 100 µM), as per the parent molecule. We also discovered that the introduction of a terminal phosphate moiety (28) at the same position produced a different trend in cytotoxicity with strong activity in BE2-C (neuroblastoma; GI(50) = 9 µM) cells; suggestive of an alternate mode of action.

Norcantharidin analogues with nematocidal activity in Haemonchus contortus.

With the major problems with resistance in parasitic nematodes of livestock to anthelmintic drugs, there is an urgent need to develop new nematocides. In the present study, we employed a targeted approach for the design of a series of norcantharidin analogues (n=54) for activity testing against the barber's pole worm (Haemonchus contortus) of small ruminants in a larval development assay (LDA) and also for toxicity testing on nine distinct human cell lines. Although none of the 54 analogues synthesized were toxic to any of these cell lines, three of them (N-octyl-7-oxabicyclo(2.2.1)heptane-2,3-dicarboximide (B2), N-decyl-7-oxabicyclo(2.2.1)heptane-2,3-dicarboximide (B3) and 4-[(4-methyl)-3-ethyl-2-methyl-5-phenylfuran-10-oxa-4-azatricyclo[5.2.1]decane-3,5-dione (B21) reproducibly displayed 99-100% lethality to H. contortus in LDA, with LD(50s) of 25-40 µM. The high 'hit rate' (5.6%) indicates that the approach taken here has advantages over conventional drug screening methods. A major advantage of norcantharidin analogues over some other currently available anthelmintics is that they can be produced in one to two steps in large amounts at low cost and high purity, and do not require any additional steps for the isolation of the active isomer. This positions them well for commercial development.