An ingenious non-spherical mesoporous silica nanoparticle cargo with curcumin induces mitochondria-mediated apoptosis in breast cancer (MCF-7) cells.

Curcumin delivery to cancer cells is challenging due to its hydrophobic nature, low bio distribution and low availability. Many nano vehicles suffer from low stability and toxicity, and hence the prerequisite of a non-toxic nano vehicle with effective drug delivery is still being delved. The present study investigates the delivery efficiency of curcumin with non-spherical mesoporous silica nanoparticles (MSNAs). Their mechanism of drug delivery and signalling proteins activated to induce apoptosis was further explored in MCF-7 cells. A non-spherical MSN was synthesised, functionalised with PEI (MSNAP) and analysed its intracellular behaviour. Our result indicates that MSNAP was non-toxic until 20 µg/mL and likely localizes in cytoplasmic vesicles. On contrast, well-known MCM-41P induced autophagosome formation, indicating cellular toxicity. Curcumin was loaded on MSNAP and its effectiveness in inducing cell death was studied in MCF-7 and in MCF-7R cells. Curcumin loading on MSNAP induces better cell death with 30 µM curcumin, better than unbounded curcumin. Western blot analysis suggest, curcumin induce apoptosis through the activation of caspase 9, 6, 12, PARP, CHOP and PTEN. The cell survival protein Akt1 was downregulated by curcumin with and without the nanostructure. Interestingly, cleaved caspase 9 was activated in higher amount in nano-conjugated curcumin compared to the free curcumin. But other ER resident protein like IRE1α, PERK and GRP78 were downregulated indicating curcumin disturbs ER homeostasis. Further, electron microscopic analysis reveled that nanocurcumin induced apoptosis by disrupting mitochondria and nucleus. Our results with doxorubicin resistant MCF-7 cell lines confirm nanodelivery of doxorubicin and curcumin sensitised cells effectively at lesser concentration. Further docking studies of curcumin indicate it interacts with the apoptotic proteins through hydrogen bonding formation and with higher binding energy.

Polyethylenimine-modified curcumin-loaded mesoporus silica nanoparticle (MCM-41) induces cell death in MCF-7 cell line.

Breast cancer accounts for the first highest mortality rate in India and second in world. Though current treatment strategies are effectively killing cancer cells, they also end in causing severe side effects and drug resistance. Curcumin is a nutraceutical with multipotent activity but its insolubility in water limits its therapeutic potential as an anti-cancer drug. The hydrophilicity of curcumin could be increased by nanoformulation or changing its functional groups. In this study, curcumin is loaded on mesoporous silica nanoparticle and its anti-cancer activity is elucidated with MCF-7 cell death. Structural characteristics of Mobil Composition of Matter - 41(MCM-41) as determined by high-resolution transmission electron microscopy (HR-TEM) shows that MCM-41 size ranges from 100 to 200 nm diameters with pore size 2-10 nm for drug adsorption. The authors found 80-90% of curcumin is loaded on MCM-41 and curcumin is released efficiently at pH 3.0. The 50 µM curcumin-loaded MCM-41 induced 50% mortality of MCF-7 cells. Altogether, their results suggested that increased curcumin loading and sustained release from MCM-41 effectively decreased cell survival of MCF-7 cells in vitro.

Insights on the involvement of (-)-epigallocatechin gallate in ER stress-mediated apoptosis in age-related macular degeneration.

Endoplasmic reticulum (ER) stress-mediated apoptosis is a well-known factor in the pathogenesis of age-related macular degeneration (AMD). ER stress leads to accumulation of misfolded proteins, which in turn activates unfolded protein response (UPR) of the cell for its survival. The prolonged UPR of ER stress promotes cell death; however, the transition between adaptation and ER stress-induced apoptosis has not been clearly understood. Hence, the present study investigates the regulatory effect of (-)-epigallocatechin gallate (EGCG) on ER stress-induced by hydrogen peroxide (H2O2) and disturbance of calcium homeostasis by thapsigargin (TG) in mouse retinal pigment epithelial (MRPE) cells. The oxidant molecules influenced MRPE cells showed an increased level of intracellular calcium [Ca2+]i in ER and transferred to mitochondria through ER-mitochondrial tether site then increased ROS production. EGCG restores [Ca2+]i homeostasis by decreasing ROS production through inhibition of prohibitin1 which regulate ER-mitochondrial tether site and inhibit apoptosis. Effect of EGCG on ER stress-mediated apoptosis was elucidated by exploring the UPR signalling pathways. EGCG downregulated GRP78, CHOP, PERK, ERO1α, IRE1α, cleaved PARP, cleaved caspase 3, caspase 12 and upregulated expression of calnexinin MRPE cells. In addition to this, inhibition of apoptosis by EGCG was also confirmed with expression of proteins Akt, PTEN and GSK3ß. MRPE cells with EGCG upregulates phosphorylation of Akt at ser473 and phospho ser380 of PTEN, but phosphorylation at ser9 of GSK3ß was inhibited. Further, constitutively active (myristoylated) CA-Akt transfected in MRPE cells had an increased Akt activity in EGCG influenced cells. These findings strongly suggest that antioxidant molecules inhibit cell death through the proper balancing of [Ca2+]i and ROS production in order to maintain UPR of ER in MRPE cells. Thus, modulation of UPR signalling may provide a potential target for the therapeutic approaches of AMD.

Role of ZnS Nanoparticles on Endoplasmic Reticulum Stress-mediated Apoptosis in Retinal Pigment Epithelial Cells.

Age-related macular degeneration (AMD) is the leading cause for irreversible visual impairment affecting 30-50 million individuals every year. Oxidative stress and endoplasmic reticulum stress have been identified as crucial factors for the pathogenesis of AMD. Current treatments do not focus on underlying stimuli responsible for the disease like AMD. Zinc is an important trace metal in retina and its deficiency leads to AMD. Recent studies on zinc sulphide nanoparticles (ZnS-NPs) are gaining attention in the field of physical and biological research. In this present study, in investigating the role of ZnS-NPs on hydrogen peroxide and thapsigargin-treated primary mice retinal pigment epithelial (MRPE) cells, we synthesized ZnS-NPs and characterized using atomic force microscope (AFM) and SEM-EDX. The ZnS-NPs abrogate the primary MRPE cell death through inhibition of oxidative stress-induced reactive oxygen species production and cell permeability. Oxidant molecules hydrogen peroxide and thapsigargin alter unfolded protein response such as glucose-regulated protein 78 (GRP78) and C/EBP homology protein (CHOP) expressions, whereas ZnS-NPs-pre-treated primary MRPE cells downregulated the overexpression of such proteins. The expressions of apoptotic proteins caspase 12 and cleaved caspase 9 and caspase 3 were also significantly controlled in ZnS-NPs-treated primary MRPE cells when comparing with thapsigargin- and hydrogen peroxide-treated cells. From these results, ZnS-NPs stabilize reactive oxygen species elevation, when subjected to hydrogen peroxide- and thapsigargin-mediated oxidant injury and helps in maintaining normal homeostasis through regulating endoplasmic reticulum (ER) stress response proteins which is the lead cause for apoptosis-mediated pathogenesis of AMD.

Gold nanoparticles downregulate VEGF-and IL-1ß-induced cell proliferation through Src kinase in retinal pigment epithelial cells.

Proliferative vitreo retinopathy (PVR) is one of the ocular complications, marked by the enhanced proliferation of various cells including retinal pigment epithelial cells (RPE). The aim of the present study is to analyze the effect of gold nanoparticles (Au-NP) on vascular endothelial growth factor (VEGF) and interleukin-1 beta (IL-1ß)-induced cell spreading, migration and proliferation in RPE cells. Au-NP (300 nM) significantly blocked the VEGF-and IL-1ß-induced cell spreading, migration and proliferation in bovine RPE cells (BRPEs). To elucidate the signaling mechanism of VEGF- and IL-1ß-induced cell proliferation, BRPEs were treated with PP2, a Src inhibitor. Further, to clarify the possible involvement of the Src pathway on the inhibitory effect of Au-NPs, transient transfection assay was performed using dominant negative (DN) and constitutively active (CA) mutant plasmid of Src kinase. The results showed that VEGF and IL-1ß exert their proliferative effects through the activation of Src kinase whereas CA Src rescued the inhibitory effect of Au-NP in presence or absence of VEGF and IL-1ß in BRPEs. Further, an in vitro kinase assay was performed to identify the status of Src phosphorylation at Y419. We found that VEGF and IL-1ß increased Src phosphorylation in BRPEs and Au-NP blocked the VEGF- and IL-1ß-induced Src phosphorylation at Y419. Taken together, our result suggests that Au-NP could effectively inhibit the VEGF- and IL-1ß-induced proliferation and migration by suppressing the Src kinase pathway in BRPEs and Au-NP might act as an effective therapeutic agent for the treatment of ocular diseases such as proliferative vitreo retinopathy.

Novel mitochondrial DNA mutations implicated in Noonan syndrome.

We report a case of Noonan syndrome with compound mutations in a sarcomeric contractile protein gene and several novel mutations in mitochondrial genes. Our case forms the first report, which emphasizes the importance of mtDNA mutations in Noonan syndrome and extends the scope for mitochondrial related syndromes.