Design and synthesis of coumarin-based organoselenium as a new hit for myeloprotection and synergistic therapeutic efficacy in adjuvant therapy.

A newly designed organoselenium compound, methyl substituted umbelliferone selenocyanate (MUS), was synthesized as a primary hit against the myelotoxic activity of carboplatin. MUS was administered at 6 mg/kg b.wt, p.o. in concomitant and pretreatment schedules with carboplatin (12 mg/kg b.wt, i.p. for 10 days) in female Swiss albino mouse. MUS treatment reduced (P < 0.001) the percentage of chromosomal aberrations, micronuclei formation, DNA damage and apoptosis in murine bone marrow cells and also enhanced (P < 0.001) the bone marrow cell proliferation of the carboplatin-treated mice. These activities cumulatively restored the viable bone marrow cell count towards normalcy. Myeloprotection by MUS was achieved, in part, due to a significant reduction in the ROS/RNS formation and restoration of glutathione redox pool. Additionally, MUS synergistically enhanced the cytotoxicity of carboplatin against two human cancer cell lines (MCF-7 and Colo-205). Furthermore, MUS can effectively potentiate the antitumour activity of carboplatin against two murine cancers (Dalton's Lymphoma and Sarcoma-180) in vivo. These preclinical findings clearly indicate that MUS can improve the therapeutic index of carboplatin and ensures more effective therapeutic strategy against cancer for clinical development.

Atypical G Protein ß5 Promotes Cardiac Oxidative Stress, Apoptosis, and Fibrotic Remodeling in Response to Multiple Cancer Chemotherapeutics.

The clinical use of multiple classes of cancer chemotherapeutics is limited by irreversible, dose-dependent, and sometimes life-threatening cardiotoxicity. Though distinct in their mechanisms of action, doxorubicin, paclitaxel, and 5-FU all induce rapid and robust upregulation of atypical G protein Gß5 in the myocardium correlating with oxidative stress, myocyte apoptosis, and the accumulation of proinflammatory and profibrotic cytokines. In ventricular cardiac myocytes (VCM), Gß5 deficiency provided substantial protection against the cytotoxic actions of chemotherapeutics, including reductions in oxidative stress and simultaneous attenuation of ROS-dependent activation of the ATM and CaMKII proapoptotic signaling cascades. In addition, Gß5 loss allowed for maintenance of Δψm, basal mitochondrial calcium uniporter expression, and mitochondrial Ca2+ levels, effects likely to preserve functional myocyte excitation-contraction coupling. The deleterious effects of Gß5 are not restricted to VCM, however, as Gß5 knockdown also reduces chemotherapy-induced release of proinflammatory cytokines (e.g., TNFα), hypertrophic factors (e.g., ANP), and profibrotic factors (e.g., TGFß1) from both VCM and ventricular cardiac fibroblasts, with the most dramatic reduction occurring in cocultured cells. Our experiments suggest that Gß5 facilitates the myofibroblast transition, the persistence of which contributes to pathologic remodeling and heart failure. The convergence of Gß5-mediated, ROS-dependent signaling pathways in both cell types represents a critical etiological factor in the pathogenesis of chemotherapy-induced cardiotoxicity. Indeed, intracardiac injection of Gß5-targeted shRNA allowed for heart-specific protection against the damaging impact of chronic chemotherapy. Together, our results suggest that inhibition of Gß5 might represent a novel means to circumvent cardiotoxicity in cancer patients whose treatment regimens include anthracyclines, taxanes, or fluoropyrimidines.Significance: These findings suggest that inhibiting an atypical G-protein might provide a strategy to limit the cardiotoxicity in cancer patients treated with anthracyclines, taxanes, or fluoropyrimidines. Cancer Res; 78(2); 528-41. ©2017 AACR.

Sensitization of cancer cells to cyclophosphamide therapy by an organoselenium compound through ROS-mediated apoptosis.

Induction of apoptosis has been recognized as an excellent therapeutic approach in cancer. Selenium based compounds are well known for their antitumor and synergistic chemotherapeutic efficacy when combined with a standard antineoplastic drug. Previously, we have reported that an organoselenium compound, diphenylmethyl selenocyanate (DMSE) could effectively protect normal organs and tissues from the toxicity induced by a standard chemotherapeutic drug cyclophosphamide in a tumor bearing mouse model. In this study, as a further step, we have evaluated the effect of DMSE in sensitization of tumor cells to cyclophosphamide-induced cell death. We found that DMSE alone or in combination with cyclophosphamide could induce cell death mainly through apoptosis. Generation of reactive oxygen species (ROS) followed by down-regulation of antioxidant defense system in the tumor cells was hypothesized as the crucial cellular events occurred following DMSE treatment. In addition, DMSE in combination with cyclophosphamide also caused DNA damage in tumor cells which might be due to the consequence of oxidative stress induced by the combined therapy. Moreover, production of ROS subsequently activated p53, which in turn initiated release of mitochondrial cytochrome c via up-regulation of Bax and down-regulation of Bcl-2. Ultimately, the activation of caspase-3 played the major role to cleave PARP that finally led to apoptosis. All the above results together proposed that, DMSE sensitized tumor cells to cyclophosphamide therapy through ROS-induced p53 activation and mitochondria-mediated caspase dependent apoptosis.

Molecular mechanism behind the synergistic activity of diphenylmethyl selenocyanate and Cisplatin against murine tumor model.

Various preclinical, clinical and epidemiological studies have already well established the cancer chemopreventive and chemoprotective potential of selenium compounds. In addition to its protective efficacy, recent studies have also proved the abilities of selenium compounds to induce cell death specifically in malignant cells. Therefore, our intention is to improve the therapeutic efficacy of an alkylating agent, cisplatin, by the adjuvant use of an organoselenium compound, diphenylmethyl selenocyanate (DMSE). It was observed that combined treatment decreased the tumor burden significantly through reactive oxygen species generation and modulation of antioxidant and detoxifying enzyme system in tumor cells. These activities ultimately led to significant DNA damage and apoptosis in tumor cells. Study of the molecular pathway disclosed that the adjuvant treatment caused induction of p53, Bax and suppressed Bcl-2 followed by the activation of caspase cascade. Furthermore, a concomitant decrease in cisplatin-induced nephrotoxicity and hematopoietic toxicity by DMSE might also have enhanced the efficacy of cisplatin and provided survival advantage to the host. Results suggested that the combination treatment with DMSE and cisplatin may offer potential therapeutic benefit, and utilization of cisplatin in cancer chemotherapy exempt of its limitations.

2-[5-Selenocyanato-pentyl]-6-amino-benzo[de]isoquinoline-1,3-dione inhibits angiogenesis, induces p53 dependent mitochondrial apoptosis and enhances therapeutic efficacy of cyclophosphamide.

The present study embodies a detailed investigation of the chemoenhancement property of a synthetic organoselenium compound, 2-[5-selenocyanato-pentyl]-7-amino benzo[de]isoquinoline-1,3-dione (ANOS) in tumor bearing Swiss albino mice. The results accumulated from this study illustrated that the administration of ANOS significantly potentiated the therapeutic efficacy of cyclophosphamide by reducing the tumor burden and chemotherapy induced toxicity in the host. Ability of ANOS in inducing apoptosis and inhibiting angiogenesis was thought to be the crucial effecter for enhancing the therapeutic efficacy of cyclophosphamide. Fluorescence microscopic study revealed that ANOS was capable of penetrating tumor cells and distributed in the subcellular compartments. We showed that ANOS-induced apoptosis, as evidenced by the TUNEL assay and cleavage of poly(ADP-ribose) polymerase (PARP), involved ROS production and DNA damage in tumor cells. ROS production subsequently activated p53 phosphorylation at Ser-15. This in turn activated cytochrome c (cyt c) release from mitochondria via Bcl-2 and Bax. Finally activation of caspase 3 led to PARP cleavage and apoptosis. These results suggested that p53 dependent mitochondrial pathway was playing an important role in ANOS induced apoptosis of tumor cells. Administration of ANOS also resulted in significant improvement of tumor vasculature and sprouting of the peritoneal cavity along with the normalization of MMP-9 level in serum and ascites fluid of tumor bearing mice. This potential antiangiogenic activity of ANOS also facilitated the therapeutic efficacy of the combination therapy. Furthermore, ANOS significantly suppressed cyclophosphamide-induced liver, hematopoietic and genetic damages. A concomitant decrease in drug-induced toxicity by ANOS might also have enhanced the efficacy of cyclophosphamide by improving the intrinsic defense machineries of the host.

Vanadium as a chemoprotectant: effect of vanadium(III)-L-cysteine complex against cyclophosphamide-induced hepatotoxicity and genotoxicity in Swiss albino mice.

Vanadium is an essential micronutrient for living systems and has antioxidant and genoprotective property. In the present study, the protective role of an organovanadium compound vanadium(III)-L-cysteine (VC-III) was evaluated against hepatotoxicity and genotoxicity induced by cyclophosphamide (CP) (25 mg/kg b.w., i.p.) in Swiss albino mice. Treatment with VC-III (1 mg/kg b.w., p.o.) mitigated CP-induced hepatic injury as indicated by reduction in activities of alanine transaminase, aspartate transaminase, alkaline phosphatase by 1.57-, 1.58- and 1.32-fold in concomitant treatment schedule and by 1.83-, 1.77- and 1.45-fold in pretreatment schedule, respectively, and confirmed by histopathological evidences. Parallel to these changes, VC-III ameliorated CP-induced oxidative stress in liver by 1.46-, 1.26-, 1.32- and 1.42-fold in concomitant treatment group and by 1.95-, 1.40-, 1.46- and 1.73-fold in pretreatment group at the level of H2O2, superoxide, nitric oxide and lipid peroxidation, respectively. VC-III also enhanced activities of antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase and glutathione (reduced) level in mice liver by 1.46-, 1.37-, 1.29-, 1.44- and 1.45-fold in concomitant treatment schedule and by 1.64-, 1.65-, 1.42-, 1.49- and 1.57-fold in pretreatment schedule, respectively. In addition, the organovanadium compound could efficiently attenuate CP-induced chromosomal aberrations, DNA fragmentation and apoptosis in bone marrow cells and DNA damage in lymphocytes by 1.49-, 1.43-, 1.48- and 1.59-fold in concomitant treatment group and by 1.76-, 1.92-, 1.99- and 2.15-fold in pretreatment group, respectively. Thus, the present study showed that VC-III could exert protection against CP-induced hepatotoxicity and genotoxicity.

Intervention in cyclophosphamide induced oxidative stress and DNA damage by a flavonyl-thiazolidinedione based organoselenocyanate and evaluation of its efficacy during adjuvant therapy in tumor bearing mice.

A novel flavonyl-thiazolidinedione based organoselenocyanate compound was synthesized and established as nontoxic at the doses of 2.5 and 5 mg/kg b.w. in mice. Oral administration of the compound in combination with cyclophosphamide (CP) resulted in an improved therapeutic efficacy which was mostly evidenced in terms of tumor burden and protection of normal cells. The adjuvant therapy was proved to be immensely significant in increasing the mean survivability of the tumor bearing hosts. Reduction in the tumor volume was manifested through the induction of apoptosis and generation of ROS in transformed cells. Moreover, the organoselenium compound could efficiently suppress CP-induced DNA damage, chromosomal aberration, hepatic damage and enhanced the activities of various antioxidant enzymes in normal cells.

Unveiling the groove binding mechanism of a biocompatible naphthalimide-based organoselenocyanate with calf thymus DNA: an "ex vivo" fluorescence imaging application appended by biophysical experiments and molecular docking simulations.

The present study embodies a detailed investigation of the binding modes of a potential anticancer and neuroprotective fluorescent drug, 2-(5-selenocyanato-pentyl)-6-chloro benzo[de]isoquinoline-1,3-dione (NPOS) with calf thymus DNA (ctDNA). Experimental results based on spectroscopy, isothermal calorimetry, electrochemistry aided with DNA-melting, and circular dichroism studies unambiguously established the formation of a groove binding network between the NPOS and ctDNA. Molecular docking analysis ascertained a hydrogen bonding mediated 'A-T rich region of B-DNA' as the preferential docking site for NPOS. The cellular uptake and binding of NPOS with DNA from "Ehrlich Ascites Carcinoma" cells confirmed its biocompatibility within tumor cells. Experimental and ex vivo cell imaging studies vividly signify the importance of NPOS as a potential prerequisite for its use in therapeutic purposes.

Effects of organoselenium compound 2-(5-selenocyanato-pentyl)-benzo[de]isoquinoline 1,3-dione on cisplatin induced nephrotoxicity and genotoxicity: an investigation of the influence of the compound on oxidative stress and antioxidant enzyme system.

Cisplatin is one of the most active cytotoxic agents used in the treatment of cancer. However, cisplatin therapy is also associated with severe side effects like nephrotoxicity and genotoxicity. Free oxygen radicals are known to play a major role in cisplatin induced toxicities. Selenium is believed to be an important trace element and dietary antioxidant because of its ability to scavenge free oxygen radicals, thereby preventing cells from oxidative stress. The purpose of this study is to evaluate the protective role of a novel naphthalimide based organoselenium compound 2-(5-selenocyanato-pentyl)-benzo[de]isoquinoline 1,3-dione against cisplatin induced toxicities in Swiss albino mice. Cisplatin was administered intraperitoneally (5 mg/kg b.w.) and the organoselenium compound was given by oral gavages (3 mg/kg b.w.) in concomitant and pretreatment schedule. The results showed that the test compound substantially reduced cisplatin induced reactive oxygen species generation and lipid peroxidation in kidney as well as blood urea nitrogen and creatinine levels in serum. Treatment with organoselenium compound was also able to restore the renal antioxidant system by modulating the cisplatin induced depleted activities of glutathione S-transferase, thioredoxin reductase, superoxide dismutase, catalase, glutathione peroxidase and reduced glutathione level. In addition, the organoselenium compound could efficiently minimize cisplatin induced chromosomal aberrations in bone marrow cells and extent of DNA damage in lymphocytes. Furthermore, the chemoprotective efficacy of the compound against cisplatin induced toxicity was confirmed by histopathological evaluation. The results suggest that the organoselenium compound has the potential to protect against cisplatin induced nephrotoxicity and genotoxicity in part by scavenging reactive oxygen species and by up regulating the antioxidant enzyme system.

Influence of novel naphthalimide-based organoselenium on genotoxicity induced by an alkylating agent: the role of reactive oxygen species and selenoenzymes.

OBJECTIVE: The protection conferred by a series of synthetic organoselenium compounds against genotoxicity and oxidative stress induced by a reference mutagen cyclophosphamide (CP) was assessed. METHOD: Genotoxicity was induced in mice by CP treatment (25 mg/kg b.w.) for 10 consecutive days. Organoselenium compounds (3 mg/kg b.w.) were administered orally in a concomitant and pretreatment schedule. DNA damage in peripheral blood lymphocytes and frequency of chromosomal aberration in the bone marrow cells were measured. Liver tissues were collected for analysis of the activity of antioxidant and detoxifying enzymes, lipid peroxidation (LPO) level, glutathione content, and histopathology. RESULTS: Exposure to CP not only led to a significant increase in the percent of chromosomal aberration and DNA damage, but also enhanced generation of hepatic reactive oxygen species (ROS) and LPO level. The organoselenium compounds demonstrated marked functional protection against CP-induced genotoxicity. DNA damage and chromosomal aberration along with ROS generation were attenuated in the organoselenium-treated mice compared with the CP-treated control mice. CP caused marked depression in the activities of the selenoenzymes (glutathione peroxidase (GPx) and thioredoxin reductase (TRxR)) and other detoxifying and antioxidant enzymes, while treatment with organoselenium compounds restored all these activities towards normal. DISCUSSION: The protective effect of these compounds may be primarily associated with the improvement of the activity of antioxidant and detoxifying enzymes (including the selenoenzymes, GPx, and TRxR) that are known to protect the DNA and other cellular components from oxidative damage.

Amelioration of cisplatin-induced nephrotoxicity in mice by oral administration of diphenylmethyl selenocyanate.

Cisplatin is one of the most potent and active cytotoxic drug in the treatment of cancer. However, side-effects in normal tissues and organs, notably nephrotoxicity in the kidneys, limit the promising efficacy of cisplatin. The present study was designed to ascertain the possible in vivo protective potential of a synthetic organoselenium compound diphenylmethyl selenocyanate (3 mg/kg.b.w.) against the nephrotoxic damage induced by cisplatin (5 mg/kg.b.w. for 5 days) in Swiss albino mice. Treatment with diphenylmethyl selenocyanate markedly reduced cisplatin-induced lipid peroxidation, serum creatinine and blood urea nitrogen levels. Renal antioxidant defense systems, such as glutathione-S-transferase, glutathione peroxidase, superoxide dismutase, catalase, activities and reduced glutathione level, depleted by cisplatin therapy, were restored to normal by the selenium compound. The selenium compound also reduced renal tubular epithelial cell damage, nitric oxide levels and expression of COX-2, and iNOS in kidneys injured by cisplatin. These results demonstrate the protective effect of diphenylmethyl selenocyanate against cisplatin-induced nephrotoxicity in mice.

Naphthalimide based novel organoselenocyanates: finding less toxic forms of selenium that would retain protective efficacy.

A series of naphthalimide based organoselenocyanates were synthesized and screened for their toxicity as well as their ability to modulate several detoxifying/antioxidative enzyme levels at a primary screening dose of 3 mg/kg b.w. in normal Swiss albino mice for 30 days. Compound 4d showed highest activity in elevating the detoxifying/antioxidant enzymes levels.