BODIPY appended copper(II) complexes of curcumin showing mitochondria targeted remarkable photocytotoxicity in visible light

Copper(II) complexes of BODIPY (borondipyrromethene) derivatives (L-1, L-2) and curcumin (Hcur), viz. Cu(L-1)(cur)]Cl (1) and Cu(L-2)(cur)]Cl (2), where L-1 and L-2 are the non-iodinated and diiodinated BODIPY appended dipicolylamine ligands, are prepared and characterized and their photocytotoxic activity in visible light studied. Binding to copper(II) has rendered stability to curcumin from its hydrolytic degradation in buffer medium. The complexes show mitochondrial localization in HeLa cells emphasizing the findings that both 1 and 2 are mitochondria-targeting complexes and induce cancer cell death. Complex 1 with a fluorophoric BODIPY moiety in L-1 gave IC50 values of 7.9(+/- 0.3) mu M in visible light (400-700 nm) and 29.1(+/- 0.5) mu M in the dark. Complex 2 having a diiodo BODIPY moiety in L-2 as a photosensitizer gave IC50 values of 3.8(+/- 0.2) mu M in visible light and 32.1(+/- 0.4) mu M in the dark. The PDT effect of 2 is comparable to that of Photofrin (R), an FDA approved PDT drug. Cell death follows an apoptotic pathway with the formation of reactive oxygen species (ROS).

Polypyridyl iron(II) complexes showing remarkable photocytotoxicity in visible light

Iron(II) complexes of polypyridyl ligands (B), viz. Fe(B)(2)]Cl-2 (1 and 2) of N, N, N-donor 2-(2-pyridyl)-1,10-phenanthroline (pyphen in 1) and 3-(pyridin-2-yl)dipyrido3,2-a:2',3'-c]phenazine (pydppz in 2), are prepared and characterized. They are 1:2 electrolytes in aqueous DMF. The diamagnetic complexes exhibit metal to ligand charge transfer band near 570 nm in DMF. The complexes are avid binders to calf thymus DNA giving binding constant (K (b)) values of similar to 10(6) M-1 suggesting significant intercalative DNA binding of the complexes due to presence of planar phenanthroline bases. Complex 2 exhibits significant photocytotoxicity in immortalized human keratinocyte cells HaCaT and breast cancer cell line MCF-7 giving IC50 values of 0.08 and 13 mu M in visible light (400-700 nm). Complex 2 shows only minor dark toxicity in HaCaT cells but is non-toxic in dark in MCF-7 cancer cells. The light-induced cellular damage follows apoptotic pathway on generation of reactive oxygen species as evidenced from the dichlorofluorescein diacetate (DCFDA) assay.

Methotrexate Promotes Platelet Apoptosis via JNK-Mediated Mitochondrial Damage: Alleviation by N-Acetylcysteine and N-Acetylcysteine Amide

Thrombocytopenia in methotrexate (MTX)-treated cancer and rheumatoid arthritis (RA) patients connotes the interference of MTX with platelets. Hence, it seemed appealing to appraise the effect of MTX on platelets. Thereby, the mechanism of action of MTX on platelets was dissected. MTX (10 mu M) induced activation of pro-apoptotic proteins Bid, Bax and Bad through JNK phosphorylation leading Delta psi m dissipation, cytochrome c release and caspase activation, culminating in apoptosis. The use of specific inhibitor for JNK abrogates the MTX-induced activation of pro-apoptotic proteins and downstream events confirming JNK phosphorylation by MTX as a key event. We also demonstrate that platelet mitochondria as prime sources of ROS which plays a central role in MTX-induced apoptosis. Further, MTX induces oxidative stress by altering the levels of ROS and glutathione cycle. In parallel, the clinically approved thiol antioxidant N-acetylcysteine (NAC) and its derivative N-acetylcysteine amide (NACA) proficiently alleviate MTX-induced platelet apoptosis and oxidative damage. These findings underpin the dearth of research on interference of therapeutic drugs with platelets, despite their importance in human health and disease. Therefore, the use of antioxidants as supplementary therapy seems to be a safe bet in pathologies associated with altered platelet functions.

New dimeric carbazole-benzimidazole mixed ligands for the stabilization of human telomeric G-quadruplex DNA and as telomerase inhibitors. A remarkable influence of the spacer

for selectively targeting cancer cells. Herein, we report the design and evolution of a new kind of carbazole-based benzimidazole dimers for their efficient telomerase inhibition activity. Spectroscopic titrations reveal the ligands high affinity toward the G4 DNA with significantly higher selectivity over duplex-DNA. The electrophoretic mobility shift assay shows that the ligands efficiently promote the formation of 04 DNA even at a lower concentration of the stabilizing K+ ions. The TRAP-LIG assay demonstrates the ligand's potential telomerase inhibition activity and also establishes that the activity proceeds via G4 DNA stabilization. An efficient nuclear internalization of the ligands in several common cancer cells (HeLa, HT1080, and A549) also enabled differentiation between normal HFF cells in co-cultures of cancer and normal ones. The ligands induce significant apoptotic response and antiproliferative activity toward cancer cells selectively when compared to the normal cells.

Redox-Active Metal-Organic Frameworks: Highly Stable Charge-Separated States through Strut/Guest-to-Strut Electron Transfer

Molecular organization of donor and acceptor chromophores in self-assembled materials is of paramount interest in the field of photovoltaics or mimicry of natural light-harvesting systems. With this in mind, a redox-active porous interpenetrated metal-organic framework (MOF), {Cd(bpdc)(bpNDI)]4.5H(2)ODMF}(n) (1) has been constructed from a mixed chromophoric system. The -oxo-bridged secondary building unit, {Cd-2(-OCO)(2)}, guides the parallel alignment of bpNDI (N,N-di(4-pyridyl)-1,4,5,8-naphthalenediimide) acceptor linkers, which are tethered with bpdc (bpdcH(2)=4,4-biphenyldicarboxylic acid) linkers of another entangled net in the framework, resulting in photochromic behaviour through inter-net electron transfer. Encapsulation of electron-donating aromatic molecules in the electron-deficient channels of 1 leads to a perfect donor-acceptor co-facial organization, resulting in long-lived charge-separated states of bpNDI. Furthermore, 1 and guest encapsulated species are characterised through electrochemical studies for understanding of their redox properties.

Antiproliferative and tumor inhibitory studies of 2,3 disubstituted 4-thiazolidinone derivatives

4-Thiazolidinone derivatives were synthesized using T3P (R)-DMSO media as a cyclodehydrating agent. All the molecules were tested for their cytotoxicity against leukemic cell lines. The compound 3-(4-bromophenyl)-2-(4-(dimethylamino)phenyl)thiazolidin-4-one (4e) with electron donating substituent at para position of phenyl ring displayed considerable cytotoxicity against Reh and Nalm6 cells with an IC50 value of 11.9 and 13.5 mu M, respectively. Furthermore, the compound 4e tested for tumor regression studies induced by EAC in Swiss albino mouse. Both in vitro and in vivo results suggested significant antiproliferative activity of compound 4e in Reh cells and mouse tumor tissue treated with compound 4e showed multifocal areas of necrosis and numerous number of apoptotic cells. (C) 2015 Elsevier Ltd. All rights reserved.

Photoinduced DNA Crosslink Formation by Dichloridooxidovanadium(IV) Complexes of Polypyridyl Bases

Oxidovanadium(IV) complexes VO(pyphen)Cl-2] (1) and VO(pydppz)Cl-2] (2), where pyphen is 2-(2-pyridyl)-1,10-phenanthroline and pydppz is 3-(pyridin-2-yl)dipyrido3,2-a:2,3-c]phenazine, show remarkable photoinduced DNA crosslinking ability and photocytotoxicity. The complexes are non-electrolytes in DMF, 1:1 electrolytes in 20% aqueous DMF, and 1:2 electrolytes in 20% aqueous DMF upon photoirradiation with visible light of 400-700 nm. The paramagnetic complexes, which have one unpaired electron, show a d-d band near 780 nm in aqueous DMF. The IR data suggest a V=O moiety trans to a V-N bond. Complex VO(pydppz)Cl-2] (2), as a novel photoinducible nuclear ds-DNA crosslinking agent, shows visible-light-induced cytotoxicity in HeLa and MCF-7 cancer cells by an apoptotic pathway, giving IC50 values of 0.87 +/- 0.07 and 1.4 +/- 0.2 M, respectively, while being essentially nontoxic (IC50 > 40 M) in the dark and less toxic in normal MCF-10A cells.

Epithelial atrophy in oral submucous fibrosis is mediated by copper (II) and arecoline of areca nut

Exposure of oral cavity to areca nut is associated with several pathological conditions including oral submucous fibrosis (OSF). Histopathologically OSF is characterized by epithelial atrophy, chronic inflammation, juxtaepithelial hyalinization, leading to fibrosis of submucosal tissue and affects 0.5% of the population in the Indian subcontinent. As the molecular mechanisms leading to atrophied epithelium and fibrosis are poorly understood, we studied areca nut actions on human keratinocyte and gingival fibroblast cells. Areca nut water extract (ANW) was cytotoxic to epithelial cells and had a pro-proliferative effect on fibroblasts. This opposite effect of ANW on epithelial and fibroblast cells was intriguing but reflects the OSF histopathology such as epithelial atrophy and proliferation of fibroblasts. We demonstrate that the pro-proliferative effects of ANW on fibroblasts are dependent on insulin-like growth factor signalling while the cytotoxic effects on keratinocytes are dependent on the generation of reactive oxygen species. Treatment of keratinocytes with arecoline which is a component of ANW along with copper resulted in enhanced cytotoxicity which becomes comparable to IC50 of ANW. Furthermore, studies using cyclic voltammetry, mass spectrometry and plasmid cleavage assay suggested that the presence of arecoline increases oxidation reduction potential of copper leading to enhanced cleavage of DNA which could generate an apoptotic response. Terminal deoxynucleotidyl transferase dUTP Nick End Labeling assay and Ki-67 index of OSF tissue sections suggested epithelial apoptosis, which could be responsible for the atrophy of OSF epithelium.

Flow Cytometry Analysis of Cytotoxicity In Vitro and Long-Term Toxicity of HA-40wt% BaTiO3 Nanoparticles In Vivo

The development of new implantable biomaterials requires bone-mimicking physical properties together with desired biocompatible property. In continuation to our earlier published research to establish compositional dependent multifunctional bone-like properties and cytocompatibility response of hydroxyapatite (HA)-BaTiO3 composites, the toxicological property evaluation, both invitro and invivo, were conducted on HA-40wt% BaTiO3 and reported in this work. In particular, this work reports invitro cytotoxicity of mouse myoblast cells as well as invivo long-term tissue and nanoparticles interaction of intra-articularly injected HA-40wt% BaTiO3 and BaTiO3 up to the concentration of 25mg/mL in physiological saline over 12weeks in mouse model. The careful analysis of flow cytometry results could not reveal any statistically significant difference in terms of early/late apoptotic cells or necrotic cells over 8d in culture. Extensive histological analysis could not record any signature of cellular level toxicity or pronounced inflammatory response in vital organs as well as at knee joints of Balb/c mice after 12weeks. Taken together, this study establishes nontoxic nature of HA-40wt% BaTiO3 and therefore, HA-40wt% BaTiO3 can be used safely for various biomedical applications.

Comparative proteomic analysis of primordial follicles from ovaries of immature and aged rats

Age related decline in reproductive performance in women is well documented and apoptosis has been considered as one of the reasons for the decline of primordial follicle reserve. Recently we observed a decline in the efficiency of DNA repair ability in aged rat primordial follicles as demonstrated by decreased mRNA levels of DNA repair genes BRCA1 and H2AX. In the present study, a two-dimensional electrophoresis (2DE) proteomic approach was employed to identify differentially expressed proteins in primordial follicles isolated from ovaries of immature (approximate to 20 days) and aged (approximate to 400-450 days) rats. Using MALDI-TOF/TOF MS, we identified 13 differentially expressed proteins (p<0.05) which included seven up-regulated and six down-regulated proteins in aged primordial follicles. These proteins are involved in a wide range of biological functions including apoptosis, DNA repair, and the immune system. Interestingly, the differentially expressed proteins such as FIGNL1 (DNA repair) and BOK (apoptotic protein) have not been previously reported in the rat primordial follicles and these proteins can be related to some common features of ovarian aging such as loss of follicle reserve and genome integrity. The quantitative differences of two important proteins BOK and FIGNL1 observed by the proteomic analysis were correlated with the transcript levels, as determined by semi-quantitative RT-PCR. Our results improve the current knowledge about protein factors associated with molecular changes in rat primordial follicles as a function of aging and our understanding of the proteomic processes involved in degenerative changes observed in aging primordial follicles.

Visible light-induced cytotoxicity of a dinuclear iron(III) complex of curcumin with low-micromolar IC50 value in cancer cells

Photoactive metal complexes have emerged as potential candidates in the photodynamic therapy (PDT) of cancer. We present here the synthesis, characterization and visible light-triggered anticancer activity of two novel mixed-ligand oxo-bridged iron(III) complexes, viz., {Fe(L)(acac)}(2)(mu-O)](ClO4)(2) (1) and {Fe (L)(cur)}(2)(mu-O)](ClO4)(2) (2) where L is bis-(2-pyridylmethyl)-benzylamine, acac is acetylacetonate and cur is the monoanion of curcumin (bis(4-hydroxy-3-methoxyphenyl)-1,6-diene-3,5-dione). The crystal structure of complex 1 (as PF6 salt, 1a) shows distorted octahedral geometry of each iron(III) centre formed by the FeN3O3 core. The 1: 2 electrolytic complexes are stable in solution and retain their oxo-bridged identity in aqueous medium. Complex 2 has a strong absorption band in the visible region and shows promising photocytotoxicity in HeLa and MCF-7 cancer cells in visible light giving respective IC50 values of 3.1 +/- 0.4 lM and 4.9 +/- 0.5 lM while remains non-toxic in the dark (IC50 > 50 lM). The control complex 1 is inactive both in the light and dark. Complex 2 accumulates in cytoplasm of HeLa and MCF-7 cells as evidenced from fluorescence microscopy and triggers apoptotic cell death via light-assisted generation of reactive oxygen species (ROS). Taken together, complex 2 with its promising photocytotoxicity but negligible dark toxicity in cancer cells has significant photochemotherapeutic potential for applications in PDT. (C) 2015 Elsevier B.V. All rights reserved.

Endoplasmic reticulum targeting tumour selective photocytotoxic oxovanadium(IV) complexes having vitamin-B6 and acridinyl moieties

Oxovanadium(IV) complexes of vitamin-B6 Schiff base, viz., VO(HL1/L-2/L-3)(B)] Cl (1-4), where B is 2,2'-bipyridine (bpy in 1 and 2), 11-(9-acridinyl)dipyrido3,2-a:2',3'-c]phenazine (acdppz in 3 and 4), H2L1 center dot HCl is 3-hydroxy-5-(hydroxymethyl)-4-(((2-hydroxyphenyl)imino)methyl)-2-methylp yridin-1-ium chloride (in 1 and 4), HL2 is 2-(((2-(1H-imidazol-4-yl)ethyl) imino)methyl) phenol (in 2) and HL3 is 4-(((2-(1H-imidazol-4- yl)ethyl)imino)methyl)-5-(hydroxymethyl)-2-methylpyridin-3-ol (in 3) were synthesized, characterized and their cellular uptake, photo-activated cytotoxicity and intracellular localization were studied. Complexes 1a, as the perchlorate salt of 1, and 2a, as the hexafluorophosphate salt of 2, were structurally characterized. Vitamin-B6 transporting membrane carrier (VTC) mediated entry into tumour cells in preference to the normal ones seems to be responsible for the higher cellular uptake of the complexes into HeLa and MCF-7 cells over MCF-10A cells. Complexes 3 and 4 having acdppz as the photosensitizer exhibit remarkable photocytotoxicity in these cancer cells giving IC50 of < 0.9 mu M. The complexes remain non-toxic in the dark. The complexes show photo-induced apoptotic cell death via singlet oxygen (O-1(2)) generation. Fluorescence microscopy reveals specific localization of complex 4 to endoplasmic reticulum (ER) and generation of O-1(2) possibly leads to apoptotic cell death by triggering ER stress response (ERSR).

Endoplasmic reticulum targeting tumour selective photocytotoxic oxovanadium(IV) complexes having vitamin-B6 and acridinyl moieties

Oxovanadium(IV) complexes of vitamin-B6 Schiff base, viz., VO(HL1/L-2/L-3)(B)] Cl (1-4), where B is 2,2'-bipyridine (bpy in 1 and 2), 11-(9-acridinyl)dipyrido3,2-a:2',3'-c]phenazine (acdppz in 3 and 4), H2L1 center dot HCl is 3-hydroxy-5-(hydroxymethyl)-4-(((2-hydroxyphenyl)imino)methyl)-2-methylp yridin-1-ium chloride (in 1 and 4), HL2 is 2-(((2-(1H-imidazol-4-yl)ethyl) imino)methyl) phenol (in 2) and HL3 is 4-(((2-(1H-imidazol-4- yl)ethyl)imino)methyl)-5-(hydroxymethyl)-2-methylpyridin-3-ol (in 3) were synthesized, characterized and their cellular uptake, photo-activated cytotoxicity and intracellular localization were studied. Complexes 1a, as the perchlorate salt of 1, and 2a, as the hexafluorophosphate salt of 2, were structurally characterized. Vitamin-B6 transporting membrane carrier (VTC) mediated entry into tumour cells in preference to the normal ones seems to be responsible for the higher cellular uptake of the complexes into HeLa and MCF-7 cells over MCF-10A cells. Complexes 3 and 4 having acdppz as the photosensitizer exhibit remarkable photocytotoxicity in these cancer cells giving IC50 of < 0.9 mu M. The complexes remain non-toxic in the dark. The complexes show photo-induced apoptotic cell death via singlet oxygen (O-1(2)) generation. Fluorescence microscopy reveals specific localization of complex 4 to endoplasmic reticulum (ER) and generation of O-1(2) possibly leads to apoptotic cell death by triggering ER stress response (ERSR).

The cis-Diammineplatinum(II) Complex of Curcumin: A Dual Action DNA Crosslinking and Photochemotherapeutic Agent

Pt(cur)(NH3)(2)](NO3) (1), a curcumin-bound cis-diammineplatinum(II) complex, nicknamed Platicur, as a novel photoactivated chemotherapeutic agent releases photoactive curcumin and an active platinum(II) species upon irradiation with visible light. The hydrolytic instability of free curcumin reduces upon binding to platinum(II). Interactions of 1 with 5'-GMP and ct-DNA indicated formation of platinum-bound DNA adducts upon exposure to visible light (lambda = 400-700 nm). It showed apoptotic photocytotoxicity in cancer cells (IC50 approximate to 15 mu M), thus forming (OH)-O-center dot, while remaining passive in the darkness (IC50 > 200 mu M). A comet assay and platinum estimation suggest Pt-DNA crosslink formation. The fluorescence microscopic images showed cytosolic localization of curcumin, thus implying possibility of dual action as a chemo-and phototherapeutic agent.

Mitochondria-Targeting Iron(III) Catecholates for Photoactivated Anticancer Activity under Red Light

Iron(III) catecholates Fe(R-bpa)(R-dopa)Cl] (1, 2) with a triphenylphosphonium (TPP) moiety, where R-bpa is 2-(TPP-N,N-bis((pyridin-2-yl)methyl)ethanamine) chloride (TPPbpa) and R-dopa is 4-{2-(anthracen-9-yl)methylamino]ethyl}benzene-1,2-diol (andopa, 1) or 4-{2-(pyren-1-yl)-methylamino]ethyl}benzene-1,2-diol (pydopa, 2), were synthesized and their photocytotoxicity studied. Complexes 3 and 4 with phenyl-N,N-bis(pyridin-2-yl)methyl]methanamine (phbpa) were used as controls. The catecholate complexes showed an absorption band near 720 nm. The 5e(-) paramagnetic complexes showed a Fe-III/Fe-II irreversible response near -0.45 V and a quasi-reversible catechol/semiquinone couple near 0.5 V versus saturated calomel electrode (SCE) in DMF/0.1 M tetrabutylammonium perchlorate. They showed photocytotoxicity in red/visible light in HeLa, HaCaT, MCF-7, and A549 cells. Complexes 1 and 2 displayed mitochondrial localization, reactive oxygen species (ROS) generation under red light, and apoptotic cell death. Control complexes 3 and 4 exhibited uniform distribution throughout the cell. The complexes showed DNA photocleavage under red light (785 nm), forming hydroxyl radicals as the ROS.