Bio-conjugation of antioxidant peptide on surface-modified gold nanoparticles: a novel approach to enhance the radical scavenging property in cancer cell.

BACKGROUND: Functionalized gold nanoparticles are emerging as a promising nanocarrier for target specific delivery of the therapeutic molecules in a cancer cell, as a result it targeted selectively to the cancer cell and minimized the off-target effect. The functionalized nanomaterial (bio conjugate) brings novel functional properties, for example, the high payload of anticancer, antioxidant molecules and selective targeting of the cancer molecular markers. The current study reported the synthesis of multifunctional bioconjugate (GNPs-Pep-A) to target the cancer cell. METHODS: The GNPs-Pep-A conjugate was prepared by functionalization of GNPs with peptide-A (Pro-His-Cys-Lys-Arg-Met; Pep-A) using thioctic acid as a linker molecule. The GNPs-Pep-A was characterized and functional efficacy was tested using Retinoblastoma (RB) cancer model in vitro. RESULTS: The GNPs-Pep-A target the reactive oxygen species (ROS) in RB, Y79, cancer cell more effectively, and bring down the ROS up to 70 % relative to control (untreated cells) in vitro. On the other hand, Pep-A and GNPs showed 40 and 9 % reductions in ROS, respectively, compared to control. The effectiveness of bioconjugate indicates the synergistic effect, due to the coexistence of both organic (Pep-A) and inorganic phase (GNPs) in novel GNPs-Pep-A functional material. In addition to this, it modulates the mRNA expression of antioxidant genes glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT) by two-threefolds as observed. CONCLUSIONS: The effects of GNPs-Pep-A on ROS reduction and regulation of antioxidant genes confirmed that Vitis vinifera L. polyphenol-coated GNPs synergistically improve the radical scavenging properties and enhanced the apoptosis of cancer cell.

Synergistic Effect of Curcumin in Combination with Anticancer Agents in Human Retinoblastoma Cancer Cell Lines.

PURPOSE: Curcumin (diferuloylmethane), a phenolic compound obtained from the rhizome of the herb Curcuma longa, is known to have anti-proliferative and anti-tumor properties. In this study, we evaluated the cytotoxic effect of curcumin alone and in combination with individual drugs like carboplatin, etoposide, or vincristine in a human retinoblastoma (RB) cancer cell line. MATERIALS AND METHODS: A drug-drug interaction was analyzed using the median effect/isobologram method and combination index values were used to characterize the interaction as synergistic or additive. We also performed the apoptosis and cell-cycle kinetics study with single drugs in combination with curcumin in a human RB cell lines (Y79 and Weri-Rb1). RESULTS: Curcumin caused concentration-dependent decrease in cell proliferation, cell kinetics, and also induced apoptosis in both the RB cell lines. When combination of curcumin with individual drugs like carboplatin or etoposide or vincristine was treated on to RB cells, both cell viability and cell cycling were reduced and increased apoptosis was noted, in comparison with single drug treatment. These effects were significant in both the cell lines, indicating the ability of curcumin to increase the sensitivity of RB cells to chemotherapy drugs. CONCLUSION: Our in vitro findings showed that the combination of curcumin with single drug treatment showed marked synergistic inhibitory effect against RB cell lines. These results suggest that curcumin can be used as a modulator which may have a potential therapeutic value for the treatment of RB cancer patients.

Modulation of multidrug resistance 1 expression and function in retinoblastoma cells by curcumin.

OBJECTIVE: To determine the possible interaction of curcumin with P-glycoprotein (P-gp) expression and function by in vitro and in silico studies. MATERIALS AND METHODS: In this study, curcumin was compared for its potential to modulate the expression and function of P-gp in Y79 RB cells by western blot, RT-PCR (reverse transcription polymerase chain reaction) and functional assay. Further, in silico molecular modeling and docking simulations were performed to deduce the inhibitory binding mode of curcumin. RESULTS: Western blot and RT-PCR analysis decreased the expression of P-gp in a dose-dependent manner. The effect of curcumin on P-gp function was demonstrated by Rhodamine 123 (Rh123) accumulation and efflux study. Curcumin increased the accumulation of Rh123 and decreased its efflux in retinoblastoma (RB) cells. In addition, curcumin inhibited verapamil stimulated ATPase activity and photoaffinity labeling study showed no effect on the binding of 8-azido-ATP-biotin, indicating its interaction at the substrate binding site. Moreover, molecular docking studies concurrently infer the binding of curcumin into the substrate binding site of P-gp with a binding energy of -7.66 kcal/mol. CONCLUSION: These findings indicate that curcumin suppresses the MDR1 expression and function, and therefore may be useful as modulators of multidrug resistance in RB tumor.

Expression profile of genes regulated by curcumin in Y79 retinoblastoma cells.

Curcumin, a well-known chemopreventive agent from turmeric, inhibits the expression of several oncogenes and cell proliferation genes in tumor cells. This study aims to understand the precise molecular mechanism by which curcumin exerts its effects on retinoblastoma cells, by performing whole genome microarray analysis to determine the gene expression profiles altered by curcumin treatment. Curcumin suppressed cell viability and altered the cell cycle of retinoblastoma cells. We identified 903 downregulated genes and 1,319 upregulated genes when compared with the control cells after treatment with 20 µM curcumin concentration for 48 h. These genes were grouped into respective functional categories according to their biological function. We found that curcumin regulated the expression of genes that are involved in the regulation of apoptosis, tumor suppressor, cell-cycle arrest, transcription factor, and angiogenesis. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was used to validate the results of genome array, and the results were consistent with the obtained data. In conclusion, treatment of curcumin affects the expression of genes involved in various cellular functions and plays an important role in tumor metastasis and apoptosis. Thus, curcumin might be an effective chemopreventive agent for retinoblastoma cancer.

Effect of curcumin on miRNA expression in human Y79 retinoblastoma cells.

PURPOSE: Retinoblastoma (RB) is the most common intraocular malignancy in children. Deregulation of several miRNAs has been identified in RB, suggesting a potential role in tumorigenesis. Recent evidence suggests that many dietary components like folate, retinoids and curcumin act as potential anticancer/antiproliferative agents by regulating the expression of miRNA. In this study, we investigated the effect of phenolic compound curcumin on miRNA expression in Y79 RB cells. MATERIALS AND METHODS: We analyzed the expression profile of miRNA by microarray analysis and quantitative real-time polymerase chain reaction (qRT-PCR) in curcumin-treated Y79 RB cells. Transfection of miR-22 was performed using Lipofectamine 2000. Cell viability, in vitro scratch migration assay, prediction of miRNA targets and Western blot analysis were performed to determine the biological function of miR-22 in Y79 RB cells. RESULTS: In Y79 RB cells treated with curcumin, 5 human miRNAs were upregulated and 16 were downregulated as detected with the miRNA microarray analysis. miR-22, a tumor-suppressor miRNA was one of the miRNA which was upregulated by curcumin. Transfected miR-22 Y79 cells inhibited the cell proliferation and reduced the migration, and erythoblastic leukemia viral oncogene homolog 3 (Erbb3) was confirmed to be the target gene of miR-22. CONCLUSION: These observations suggest that curcumin modulate the miRNA expression profile, thereby exerting its anticancer effects on RB cells.

In vitro and In silico studies on inhibitory effects of curcumin on multi drug resistance associated protein (MRP1) in retinoblastoma cells.

Multi Drug Resistance (MDR) is one of the major causes of chemotherapy failure in human malignancies. Curcumin, the active constituent of Curcuma longa is a proven anticancer agent potentially modulating the expression and function of these MDR proteins. In this study, we attempted to test curcumin for its potential to inhibit the expression and function of multidrug resistance associated protein 1 (MRP1) in retinoblastoma (RB) cell lines through western blot, RT-PCR and functional assays. In silico analysis were also performed to understand the molecular interactions conferred by curucmin on MRP1 in RB cells. Western blot and RTPCR analysis did not show any correlation of MRP1 expression with increase in concentration of curcumin. However, inhibitory effect of curcumin on MRP1 function was observed as a decrease in the efflux of fluorescent substrate. Moreover, Curcumin did not affect 8-azido-ATP-biotin binding to MRP1 and it also showed inhibition of ATP-hydrolysis stimulated by quercetin, which is indicative of curcumin's interaction with the substrate binding site of MRP1. Furthermore, homology modelling and docking simulation studies of MRP1 also provided deeper insights into the molecular interactions, thereby inferring the potential binding mode of curcumin into the substrate binding site of MRP1.