Search

Targeted therapy is a new strategy for cancer treatment that targets chemical entities specific to cancer cells than normal ones. One of the features associated with malignancy is the elevated copper which plays an integral role in angiogenesis. Work is in progress in our lab to identify new copper chelators to target elevated copper under targeted therapy for the killing of cancer cells. Recently, a coumarin-based copper chelator, di(2-picolyl)amine-3(bromoacetyl)coumarin hybrid molecule (ligand-L) has been synthesized by us, and also studied its copper-dependent macromolecular damage response in copper overloaded lymphocytes. The present study investigates the anticancer activity of ligand-L and its mode of action in rat model of diethylnitrosamine (DEN) induced hepatocellular carcinoma. It has been found that liver tissue has a marked increase in copper levels in DEN induced hepatocellular carcinoma. Ex vivo results showed that ligand-L inhibited cell viability, induced reactive oxygen species (ROS) generation, DNA damage, loss of mitochondrial membrane potential and caspase-3 activation in isolated hepatocellular carcinoma cells (HCC). All these effects induced by ligand-L were abrogated by neocuproine and N-acetylcysteine (ROS scavenger). Further, ligand-L treatment of animals bearing hepatocellular carcinoma results in an increment in the cellular redox scavengers, lipid peroxidation and DNA breakage in malignant hepatocytes. In vivo studies using ligand-L also showed that ligand-L possesses anticancer properties as evidenced by improvement in liver marker enzymes and liver surface morphology, and reduced alpha-fetoprotein in the treated group compared to untreated cancer-induced group. Overall, this study suggests that copper-ligand-L interaction leads to ROS generation which caused DNA damage and apoptosis in malignant cells. This study provides enough support to establish ligand-L as a clinically relevant lead molecule for the treatment of different malignancies., 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 Elsevier Inc. All rights reserved.)

Cervical cancer is a leading cause of cancer-related deaths among women in developing countries. Therefore, development of new chemotherapeutic agents is required. Unlike normal cells, cancer cells contain elevated copper levels which play an integral role in angiogenesis. Thus, targeting copper via copper-specific chelators in cancer cells can serve as effective anticancer strategy. In this work, a copper chelator pregnenolone acetate nucleus-based tetrazole derivative (ligand-L) was synthesized and characterized by elemental analysis, ESI-MS, 1 H NMR and 13 C NMR. DNA binding ability of ligand-L was studied using UV-Vis and fluorescence spectroscopy. Fluorescence spectroscopy studies reveal that quenching constant of ligand-l-DNA and ligand-L-Cu(II) were found to be 7.4 × 10 3 M -1 and 8.8 × 10 3 M -1 , respectively. In vitro toxicity of ligand-L was studied on human cervical cancer C33A cancer cells. Results showed that ligand-L exhibit significant cytotoxic activity against cervical cancer C33A cells with IC 50 value 5.0 ± 1.8 µM. Further, it was found that ligand-L cytotoxicity is due to redox cycling of copper to generate ROS which leads to DNA damage and apoptosis. In conclusion, this is the report where we synthesized pregnenolone acetate-based tetrazole derivative against C33A cells that targets cellular copper to induce pro-oxidant death in cancer cells. These findings will provide significant insights into the development of new chemical molecules with better copper chelating and pro-oxidant properties against cancer cells., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Coumarin is an important bioactive pharmacophore. It is found in plants as a secondary metabolite and exhibits diverse pharmacological properties including anticancer effects against different malignancies. Therapeutic efficacy of coumarin derivatives depends on the pattern of substitution and conjugation with different moieties. Cancer cells contain elevated copper as compared to normal cells that plays a role in angiogenesis. Thus, targeting copper in malignant cells via copper chelators can serve as an attractive targeted anticancer strategy. Our previous efforts led to the synthesis of di(2-picolyl)amine-3(bromoacetyl)coumarin hybrid molecule (ligand-L) endowed with DNA/Cu(II) binding properties, and ROS generation ability in the presence of copper ions. In the present study, we aimed to validate copper-dependent cytotoxic action of ligand-L against malignant cells. For this, we used a cellular model system of copper (Cu) overloaded lymphocytes (CuOLs) to simulate malignancy-like condition. In CuOLs, lipid peroxidation/protein carbonylation, ROS generation, DNA fragmentation and apoptosis were investigated in the presence of ligand-L. Results showed that ligand-L-Cu(II) interaction leads to ROS generation, lipid peroxidation/protein carbonylation (oxidative stress parameters), DNA damage, up-regulation of p53 and mitochondrial-mediated apoptosis in treated lymphocytes. Further, pre-incubation with neocuproine (membrane permeable copper chelator) and ROS scavengers attenuated the DNA damage and apoptosis. These results suggest that cellular copper acts as molecular target for ligand-L to propagate redox cycling and generation of ROS via Fenton-like reaction leading to DNA damage and apoptosis. Further, we showed that ligand-L targets elevated copper in breast cancer MCF-7 and colon cancer HCT116 cells leading to a pro-oxidant inhibition of proliferation of cancer cells. In conclusion, we propose copper-dependent ROS-mediated mechanism for the cytotoxic action of ligand-L in malignant cells. Thus, targeting elevated copper represents an effective therapeutic strategy for selective cytotoxicity against malignant cells., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Despite substantial research on cancer therapeutics, systemic toxicity and drug-resistance limits the clinical application of many drugs like cisplatin. Therefore, new chemotherapeutic strategies against different malignancies are needed. Targeted cancer therapy is a new paradigm for cancer therapeutics which targets pathways or chemical entities specific to cancer cells than normal ones. Unlike normal cells, cancer cells contain elevated copper which plays an integral role in angiogenesis. Copper is an important metal ion associated with chromatin DNA, particularly with guanine. Thus, targeting copper via copper-specific chelators in cancer cells can serve as an effective anticancer strategy. New pharmacophore di(2-picolyl)amine (DPA)-3(bromoacetyl) coumarin (ligand-L) was synthesized and characterized by IR, ESI-MS, 1H- and 13C-NMR. Binding ability of ligand-L to DNA/Cu(II) was evaluated using a plethora of biophysical techniques which revealed ligand-L-DNA and ligand-L-Cu(II) interaction. Competitive displacement assay and docking confirmed non-intercalative binding mode of ligand-L with ctDNA. Cyclic voltammetry confirmed ligand-L causes quasi reversible Cu(II)/Cu(I) conversion. Further, acute toxicity studies revealed no toxic effects of ligand-L on mice. To evaluate the chemotherapeutic potential and anticancer mechanism of ligand-L, DNA damage via pBR322 cleavage assay and reactive oxygen species (ROS) generation were studied. Results demonstrate that ligand-L causes DNA cleavage involving ROS generation in the presence of Cu(II). In conclusion, ligand-L causes redox cycling of Cu(II) to generate ROS which leads to oxidative DNA damage and pro-oxidant cancer cell death. These findings will establish ligand-L as a lead molecule to synthesize new molecules with better copper chelating and pro-oxidant properties against different malignancies.

Cisplatin used in treatment of solid tumor induces oxidative stress which leads to hepatotoxicity and nephrotoxicity. New strategies are therefore needed to combat toxicity and optimize its therapeutic potential. Riboflavin (VitaminB2) under photoillumination works as an anti proliferative agent and induces apoptosis. These properties of riboflavin have been exploited to mitigate cisplatin induced toxicities. 9,10-dimethylbenz(a)anthracene /12-O-tetradecanoylphorbol-13-acetate  were used to induce skin tumor in Swiss albino mice. The tumor induced mice were treated with cisplatin, riboflavin as well as their combination under photo illumination. In comparison to tumor control group the cisplatin and riboflavin treated groups showed a compromised level of antioxidant enzymes, functional markers and a higher degree of lipid peroxidation. However these parameters tended towards normal in the combination treated group. The results from histopathology indicate that apoptosis was favored mode of cell death and that necrosis was reduced in combination treated groups. Our findings indicate that combination of cisplatin with riboflavin under photo illumination synergizes its anti cancer activity towards cancer cells and attenuates the cisplatin induced toxicities.

Calcitriol, the biologically active form of vitamin D, is known to function as an important anticancer agent. The exact mechanism by which calcitriol exerts its effects remains unknown. Recent evidence suggests a link between calcitriol-induced, free-radical-mediated DNA damage and cell death, in the presence of elevated levels of copper, such as those observed in malignant cells. As calcitriol is a lipid-soluble molecule, its interaction with DNA and copper would require a "chaperone"-like molecule, which binds the relatively hydrophobic calcitriol and polar DNA. A candidate protein is the vitamin D receptor (VDR), which binds both molecules. Using the recently elucidated full-length structure of the VDR molecule, we present and discuss three possible mechanisms to explain the interaction between calcitriol and DNA, as mediated by VDR., (© 2013 IUBMB.)

Background: Cisplatin is an effective anticancer drug that elicits many side effects mainly due to induction of oxidative and nitrosative stresses during prolonged chemotherapy. The severity of these side effects consequently restricts its clinical use under long term treatment. Riboflavin is an essential vitamin used in various metabolic redox reactions in the form of flavin adenine dinucleotide and flavin mononucleotide. Besides, it has excellent photosensitizing property that can be used to ameliorate these toxicities in mice under photodynamic therapy., Methods and Findings: Riboflavin, cisplatin and their combinations were given to the separate groups of mice under photoilluminated condition under specific treatment regime. Their kidney and liver were excised for comet assay and histopathological studies. Furthermore, Fourier Transform Infrared Spectroscopy of riboflavin-cisplatin combination in vitro was also conducted to investigate any possible interaction between the two compounds. Their comet assay and histopathological examination revealed that riboflavin in combination with cisplatin was able to protect the tissues from cisplatin induced toxicities and damages. Moreover, Fourier Transform Infrared Spectroscopy analysis of the combination indicated a strong molecular interaction among their constituent groups that may be assigned for the protective effect of the combination in the treated animals., Conclusion: Inclusion of riboflavin diminishes cisplatin induced toxicities which may possibly make the cisplatin-riboflavin combination, an effective treatment strategy under chemoradiotherapy in pronouncing its antineoplastic activity and sensitivity towards the cancer cells as compared to cisplatin alone.

5-Fluorouracil (5-FU) is a potent photosensitizer used in colon and rectal cancers. 5-FU on galvanostatic electrolysis or radiation-induced oxidation of aqueous solution yields N(1)-C(5)-linked dimmer hydrate of 5-FU. Copper is presently associated with chromatin; in cancer cells the concentration of copper is very high. It has been shown to be capable of mediating the action of several anticancer drugs through the production of reactive oxygen species (ROS). The objective of the present study is to determine the Cu (II)-mediated anticancer mechanism of 5-FU under photo-illumination as well as 5-FU alone. We have shown that a pro-oxidant action was enhanced when Cu (II) was used with 5-FU as compared to 5-FU alone. This may be due to the inhibition of dimerization of 5-FU when present in combination with Cu (II) under photo-illumination. It was also shown that 5-FU alone as well as in combination with Cu (II) was able to generate oxidative stress in lymphocyte which is inhibited by scavengers of ROS. Moreover, the results of Fourier-transformed infrared spectra lead to the conclusion that the dimerization of 5-FU was inhibited when used in combination with Cu (II). It was due to the interaction of 5-FU with Cu (II). Hence, we propose that during chemoradiotherapy with 5-FU, the endogenous copper is mobilized by 5-FU, leading to the generation of ROS which cause oxidative stress and possibly cancer cell death by apoptosis.

Cis-diamminedichloroplatinum (CP), a prominent anticancer drug, exerts toxic insults that are functional to various factors that compromise its antineoplastic activity. Riboflavin (RF) is an essential vitamin and photosensitizer that ameliorates CP-induced toxic insults in vivo in a dose-dependent manner. The aim of the present study is to investigate how age can influence the ameliorative effect of RF against CP-induced toxicity. Ninety male mice were divided into three age groups: young, adult, and old for the present investigation under an established treatment strategy with CP, RF, and their combinations under photoillumination for 1 mo. Their kidneys and serum samples were assessed for redox status [superoxide dismutase, catalase, reduced glutathione, malondialdehyde (MDA), carbonyl contents, and glutathione-S-transferase], biochemical analysis (renal function markers—nitric oxide), comet assay, and histopathology. The adult group showed not only the strongest resistance against the CP-induced toxicity but also the better ameliorative effect of RF followed by the young and old groups, respectively, with well-maintained redox status concomitant with the level of renal function markers, MDA, and carbonyl contents near the control values. Furthermore, comet assay and histopathological evaluation confirmed the results in a dose-dependent manner. Hence, age is an importantpatient-related factorthat can influence the final clinical outcome under personalized chemoradiotherapy. [ABSTRACT FROM PUBLISHER]

The toxicity exerted by the anticancer drug, cisplatin in vivo is functional to many factors such as dose, duration, gender and age etc. The present study is aimed to investigate if ameliorative potential of riboflavin on cisplatin induced toxicity is gender dependent. Eighty four adult mice from male and female sex were divided into seven groups ( n = 6) for both sexes. They were treated with riboflavin (2 mg/kg), cisplatin (2 mg/kg) and their two different combinations (cisplatin at 2 mg/kg with 1 mg/kg and 2 mg/kg of riboflavin) under photoillumination with their respective controls for the combination groups without photoillumination. After treatment, all groups were sacrificed and their kidney, liver and serum were collected for biochemical estimations, comet assay and histopathology. In the present investigation, it was evident from antioxidant and detoxification studies (SOD, CAT, GSH, GST, MDA and carbonyl level) that the female mice exhibited better tolerance towards cisplatin inducted toxicity and the ameliorative effect of riboflavin against cisplatin toxicity was found stronger in their combination groups as compared to the male groups as the activity of all antioxidant enzymes were found better concomitant with lower level of MDA and carbonyl contents in the female combination groups than their male counterparts. Furthermore, single cell gel electrophoresis and histopathological examination confirmed that restoration of normal nuclear and cellular integrity was more prominent in female with respect to the males after treatment in the combination groups in a dose-dependent manner. Hence, this study reveals that cisplatin is more toxic in male mice and the ameliorative effect of riboflavin against cisplatin toxicity is stronger in female mice. [ABSTRACT FROM AUTHOR]

Phytoestrogens have attracted considerable interest as natural alternatives to hormone replacement therapy and their potential as cancer therapeutic agents. Among phytoestrogens, coumestrol has shown multipharmacological properties such as antiinflammatory, neuroprotective, osteoblastic differentiation and anticancer. Though several studies have described anticancer effects of coumestrol, a clear underlying molecular mechanism has not been elucidated. Unlike normal cells, cancer cells contain elevated copper levels that play an integral role in angiogenesis. Copper is an important metal ion associated with the chromatin DNA, particularly with guanine. Thus, targeting copper in cancer cells can serve as effective anticancer strategy. Using human peripheral lymphocytes, we assessed lipid peroxidation, protein carbonylation, reactive oxygen species (ROS) generation, DNA damage and apoptosis by coumestrol in the presence of exogenously added Cu(II) in cells to simulate malignancy-like condition. Results showed that Cu(II)-coumestrol interaction leads to lipid peroxidation and protein carbonylation (markers of oxidative stress), DNA fragmentation and apoptosis in treated lymphocytes. Further, incubation of lymphocytes with ROS scavengers and membrane-permeant copper chelator, neocuproine, resulted in inhibition of DNA damage and apoptosis. This suggests that coumestrol engages in redox cycling of Cu(II) to generate ROS that leads to DNA fragmentation and apoptosis. In conclusion, this is the first report showing that coumestrol targets cellular copper to induce prooxidant death in malignant cells. We believe that such a prooxidant cytotoxic mechanism better explains the anticancer activity of coumestrol. These findings will provide significant insights into the development of new chemical molecules with better copper-chelating and prooxidant properties against cancer cells. [ABSTRACT FROM AUTHOR]

Triple-negative breast cancer (TNBC) represents the highly aggressive subgroup of breast cancers with poor prognosis due to absence of estrogen receptor (ER). Therefore, alternative targeted therapies are required against ER-negative breast cancers. Coumestrol, a phytoestrogen inhibits cell growth of ER-negative breast cancer MDA-MB-231 cells; the exact mechanism has not yet been reported. Unlike normal cells, cancer cells contain elevated copper which play an integral role in angiogenesis. The current focus of the work was to identify any possible role of copper in coumestrol cytotoxic action against breast cancer MDA-MB-231 cells. Results demonstrated that coumestrol inhibited cell viability, induced ROS generation, DNA damage, G1/S cell cycle arrest, up-regulation of Bax and apoptosis induction via caspase-dependent mitochondrial mediated pathway in MDA-MB-231 cells. Further, addition of copper chelator, neocuproine and ROS scavenger, N -acetyl cysteine were ineffective in abrogating coumestrol-mediated apoptosis. This suggests non-involvement of copper and ROS in coumestrol-induced apoptosis. To account for coumestrol-mediated up-regulation of Bax and apoptosis induction, direct binding potential between coumestrol and Bax/Bcl-2 was studied using in silico molecular docking studies. We propose that coumestrol directly enters cells and combines with Bax/Bcl-2 to alter their structures, thereby causing Bax binding to the outer mitochondrial membrane and Bcl-2 release from the mitochondria to initiate apoptosis. Thus, non-copper targeted ROS independent DNA damage is the central mechanism of coumestrol in ER-negative MDA-MB-231 cells. These findings will be useful in better understanding of anticancer mechanisms of coumestrol and establishing it as a lead molecule for TNBC treatment. [ABSTRACT FROM AUTHOR]