Graphene acid quantum dots: A highly active multifunctional carbon nano material that intervene in the trajectory towards neurodegeneration

Carbon dots (CDs) are carbon nano materials (CNMs) that find use across several biological applications because of their water solubility, biocompatible nature, eco-friendliness, and ease of synthesis. Additionally, their physiochemical properties can be chemically tuned for further optimization towards specific applications. Here, we investigate the efficacy of C70-derived Graphene Acid Quantum Dots (GAQDs) in mitigating the transformation of soluble, monomeric Hen Egg-White Lysozyme (HEWL) to mature fibrils during its amyloidogenic trajectory. Our findings reveal that GAQDs exhibit dose-dependent inhibition of HEWL fibril formation (up to 70 % at 5 mg/mL) without affecting mitochondrial membrane potential or inducing apoptosis at the same density. Furthermore, GAQDs scavenged reactive oxygen species (ROS); achieving a 50 % reduction in ROS levels at a mere 100 µg/mL when exposed to a standard free radical generator. GAQDs were not only found to be biocompatible with a human neuroblastoma-derived SHSY-5Y cell line but also rescued the cells from rotenone-induced apoptosis. The GAQD-tolerance of SHSY-5Y cells coupled with their ability to restitute cells from rotenone-dependent apoptosis, when taken in conjunction with the biocompatibility data, indicate that GAQDs possess neuroprotective potential. The data position this class of CNMs as promising candidates for resolving aberrant cellular outputs that associate with the advent and progress of multifactorial neurodegenerative disorders including Parkinson's (PD) and Alzheimer's diseases (AD) wherein environmental causes are implicated (95 % etiology). The data suggest that GAQDs are a multifunctional carbon-based sustainable nano-platform at the intersection of nanotechnology and neuroprotection for advancing green chemistry-derived, sustainable healthcare solutions.

Thiophene derivative inflicts cytotoxicity via an intrinsic apoptotic pathway on human acute lymphoblastic leukemia cells

In an effort to identify novel anti-cancer agents, we employed a well-established High Throughput Screening (HTS) assay to assess the cytotoxic effect of compounds within the ChemBridge DIVERSet Library on a lymphoma cell line. This screen revealed a novel thiophene, F8 (methyl 5-[(dimethylamino)carbonyl]-4-methyl-2-[(3-phenyl-2-propynoyl) amino]-3-thiophenecarboxylate), that displays anti-cancer activity on lymphoma, leukemia, and other cancer cell lines. Thiophenes and thiophene derivatives have emerged as an important class of heterocyclic compounds that have displayed favorable drug characteristics. They have been previously reported to exhibit a broad spectrum of properties and varied uses in the field of medicine. In addition, they have proven to be effective drugs in various disease scenarios. They contain anti-inflammatory, anti-anxiety, anti-psychotic, anti-microbial, anti-fungal, estrogen receptor modulating, anti-mitotic, kinase inhibiting and anti-cancer activities, rendering compounds with a thiophene a subject of significant interest in the scientific community. Compound F8 consistently induced cell death at a low micromolar range on a small panel of cancer cell lines after a 48 h period. Further investigation revealed that F8 induced phosphatidylserine externalization, reactive oxygen species generation, mitochondrial depolarization, kinase inhibition, and induces apoptosis. These findings demonstrate that F8 has promising anti-cancer activity.

Synthesis of Novel Pyrazole-Oxindole Conjugates with Cytotoxicity in Human Cancer Cells via Apoptosis

A novel series of pyrazole-oxindole conjugates were prepared and characterized as potential cytotoxic agents by FT-IR, NMR and HR-MS. The cytotoxic activity of these compounds was tested in the Jurkat acute T cell leukemia, CEM acute lymphoblastic leukemia, MCF10 A mammary epithelial and MDA-MB 231 triple negative breast cancer cell lines. Among the tested conjugates, 5-methyl-3-((3-(1-phenyl)-3-(p-tolyl)-1H-pyrazol-4-yl)methylene)indolin-2-one 6h emerged as the most cytotoxic with a CC50 of 4.36+/-0.2 μM against Jurkat cells. The mechanism of cell death induced by 6h was investigated through the Annexin V-FITC assay via flow cytometry. Reactive oxygen species (ROS) accumulation, mitochondrial health and the cell cycle progression were also evaluated in cells exposed to 6h. Results demonstrated that 6h induces apoptosis in a dose-response manner, without generating ROS and/or altering mitochondrial health. In addition, 6h disrupted the cell cycle distribution causing an increase in DNA fragmentation (Sub G0-G1), and an arrest in the G0-G1 phase. Taken together, the 6h compound revealed a strong potential as an antineoplastic agent evidenced by its cytotoxicity in leukemia cells, the activation of apoptosis and restriction of the cell cycle progression.

Identification of a Unique Cytotoxic Thieno[2,3-c]Pyrazole Derivative with Potent and Selective Anticancer Effects In Vitro

In recent years, the thienopyrazole moiety has emerged as a pharmacologically active scaffold with antitumoral and kinase inhibitory activity. In this study, high-throughput screening of 2000 small molecules obtained from the ChemBridge DIVERset library revealed a unique thieno[2,3-c]pyrazole derivative (Tpz-1) with potent and selective cytotoxic effects on cancer cells. Compound Tpz-1 consistently induced cell death at low micromolar concentrations (0.19 μM to 2.99 μM) against a panel of 17 human cancer cell lines after 24 h, 48 h, or 72 h of exposure. Furthermore, an in vitro investigation of Tpz-1's mechanism of action revealed that Tpz-1 interfered with cell cycle progression, reduced phosphorylation of p38, CREB, Akt, and STAT3 kinases, induced hyperphosphorylation of Fgr, Hck, and ERK 1/2 kinases, and disrupted microtubules and mitotic spindle formation. These findings support the continued exploration of Tpz-1 and other thieno[2,3-c]pyrazole-based compounds as potential small-molecule anticancer agents.

Identification of a Potent Cytotoxic Pyrazole with Anti-Breast Cancer Activity That Alters Multiple Pathways

In this study, we identified a novel pyrazole-based derivative (P3C) that displayed potent cytotoxicity against 27 human cancer cell lines derived from different tissue origins with 50% cytotoxic concentrations (CC50) in the low micromolar and nanomolar range, particularly in two triple-negative breast cancer (TNBC) cell lines (from 0.25 to 0.49 µM). In vitro assays revealed that P3C induces reactive oxygen species (ROS) accumulation leading to mitochondrial depolarization and caspase-3/7 and -8 activation, suggesting the participation of both the intrinsic and extrinsic apoptotic pathways. P3C caused microtubule disruption, phosphatidylserine externalization, PARP cleavage, DNA fragmentation, and cell cycle arrest on TNBC cells. In addition, P3C triggered dephosphorylation of CREB, p38, ERK, STAT3, and Fyn, and hyperphosphorylation of JNK and NF-kB in TNBC cells, indicating the inactivation of both p38MAPK/STAT3 and ERK1/2/CREB signaling pathways. In support of our in vitro assays, transcriptome analyses of two distinct TNBC cell lines (MDA-MB-231 and MDA-MB-468 cells) treated with P3C revealed 28 genes similarly affected by the treatment implicated in apoptosis, oxidative stress, protein kinase modulation, and microtubule stability.

The Antimalarial Drug Pyronaridine Inhibits Topoisomerase II in Breast Cancer Cells and Hinders Tumor Progression In Vivo

BACKGROUND

Breast cancer is the most frequently diagnosed cancer in women worldwide. Pyronaridine (PND), an antimalarial drug, was shown to exert anticancer activity on seventeen different human cancer cells, seven from female breast tissue. Additionally, PND induced apoptosis via mitochondrial depolarization, alteration of cell cycle progression, and DNA intercalation. However, the molecular target of PND in cells was not elucidated.

OBJECTIVE

Here, we have further investigated PND's mode of action by using transcriptome analysis. Preclinical studies were also performed to determine whether PND could affect tumor progression in a human breast cancer xenograft in mice. Moreover, we assessed the combined efficacy of PND with well-known anticancer drugs.

METHODS

Transcriptome analyses of PND-treated cancer cells were performed. Topoisomerase II activity was evaluated by an in vitro assay. In addition, daily oral administration of PND was given to mice with human breast cancer xenografts. The differential nuclear staining assay measured in-vitro cell toxicity.

RESULTS

The transcriptome signatures suggested that PND might act as a topoisomerase II inhibitor. Thus, topoisomerase inhibition assays were performed, providing evidence that PND is a bona fide topoisomerase II inhibitor. Also, in-vivo studies suggest that PND hinders tumor progression. Besides, combination studies of PND with anticancer drugs cisplatin and gemcitabine revealed higher cytotoxicity against cancer cells than individual drug administration.

CONCLUSION

The findings provide evidence that PND is a topoisomerase II inhibitor and can hinder cancer progression in an animal model, further demonstrating PND's favorable characteristics as a repurposed anticancer drug.

Ni-Cu Nanoparticles and Their Feasibility for Magnetic Hyperthermia

Ni-Cu nanoparticles have been synthesized by reducing Ni and Cu from metal precursors using a sol–gel route followed by annealing at 300 °C for 1, 2, 3, 6, 8, and 10 h for controlled self-regulating magnetic hyperthermia applications. Particle morphology and crystal structure revealed spherical nanoparticles with a cubic structure and an average size of 50, 60, 53, 87, and 87 nm for as-made and annealed samples at 300 °C for 1, 3, 6, and 10 h, respectively. Moreover, hysteresis loops indicated ferromagnetic behavior with saturation magnetization (Ms) ranging from 13–20 emu/g at 300 K. Additionally, Zero-filed cooled and field cooled (ZFC-FC) curves revealed that each sample contains superparamagnetic nanoparticles with a blocking temperature (T_B) of 196–260 K. Their potential use for magnetic hyperthermia was tested under the therapeutic limits of an alternating magnetic field. The samples exhibited a heating rate ranging from 0.1 to 1.7 °C/min and a significant dissipated heating power measured as a specific absorption rate (SAR) of 6–80 W/g. The heating curves saturated after reaching the Curie temperature (Tc), ranging from 30–61 °C within the therapeutic temperature limit. An in vitro cytotoxicity test of these Ni-Cu samples in biological tissues was performed via exposing human breast cancer MDA-MB231 cells to a gradient of concentrations of the sample with 53 nm particles (annealed at 300 °C for 3 h) and reviewing their cytotoxic effects. For low concentrations, this sample showed no toxic effects to the cells, revealing its biocompatibility to be used in the future for in vitro/in vivo magnetic hyperthermia treatment of cancer.

Thermal Bioprinting Causes Ample Alterations of Expression of LUCAT1, IL6, CCL26, and NRN1L Genes and Massive Phosphorylation of Critical Oncogenic Drug Resistance Pathways in Breast Cancer Cells

Bioprinting technology merges engineering and biological fields and together, they possess a great translational potential, which can tremendously impact the future of regenerative medicine and drug discovery. However, the molecular effects elicited by thermal inkjet bioprinting in breast cancer cells remains elusive. Previous studies have suggested that bioprinting can be used to model tissues for drug discovery and pharmacology. We report viability, apoptosis, phosphorylation, and RNA sequence analysis of bioprinted MCF7 breast cancer cells at separate timepoints post-bioprinting. An Annexin A5-FITC apoptosis stain was used in combination with flow cytometry at 2 and 24 h post-bioprinting. Antibody arrays using a Human phospho-MAPK array kit was performed 24 h post-bioprinting. RNA sequence analysis was conducted in samples collected at 2, 7, and 24 h post-bioprinting. The post-bioprinting cell viability averages were 77 and 76% at 24 h and 48 h, with 31 and 64% apoptotic cells at 2 and 24 h after bioprinting. A total of 21 kinases were phosphorylated in the bioprinted cells and 9 were phosphorylated in the manually seeded controls. The RNA seq analysis in the bioprinted cells identified a total of 12,235 genes, of which 9.7% were significantly differentially expressed. Using a ±2-fold change as the cutoff, 266 upregulated and 206 downregulated genes were observed in the bioprinted cells, with the following 5 genes uniquely expressed NRN1L, LUCAT1, IL6, CCL26, and LOC401585. This suggests that thermal inkjet bioprinting is stimulating large scale gene alterations that could potentially be utilized for drug discovery. Moreover, bioprinting activates key pathways implicated in drug resistance, cell motility, proliferation, survival, and differentiation.

2D and 3D thermally bioprinted human MCF-7 breast cancer cells: A promising model for drug discovery

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Background: Breast cancer (BC) is the second leading cause of cancer death following lung cancer. Bioprinting, the use of computer aided process to print biological living and non-living material to create patterns in 2D or 3D structures, is a novel technique that has been proposed to be used to develop tissue engineered solutions for a wide array of clinical applications, e.g., skin grafting. We investigate here if bioprinted breast cancer cells show some of the hallmarks of cancer tissues, and thus may represent good in vitro models for drug discovery. Methods: For this study, MCF-7 BC cells were cultured, stained, counted and turned into a bioink solution by suspending in phosphate buffered saline solution. The cells were bioprinted over a 96-well plate and pre-incubated for 18 hours in DMEM and RPMI media with 10% Fetal Bovine Serum and Charcoal Stripped Serum, respectively. After 18 hours of incubation the media was supplemented with Tamoxifen at 5µM, 10µM, 50µM, 90µM and 110µM concentrations. Cytotoxicity was measured 24 hours post-treatment using a differential nuclear staining assay and an INCell 2000 bioimager system. Results: Bioprinted cells exposed to high concentrations of Tamoxifen (90 µM and 110µM) exhibited a viability of 8.2% and 10.8%, respectively. Whereas viability of manually seeded cells at those concentrations was 0.11% and 0.05%. Viability of negative and positive controls was at 7.6% and 97.0% for the bioprinted samples and for the normally seeded cells was 4.9% and 98.8% respectively. Conclusions: In our study, we have established a novel 2D/3D breast tumor model applying bioprinting technology for drug discovery. The higher cell viability of MCF-7’s at high concentrations of Tamoxifen could be attributed to the hormesis effect and activation of chaperone proteins, e.g., HSP70 and HSP90, possibly caused by bioprinting. We hypothesize that bioprinted MCF-7 cells also show increased levels of chaperone proteins, which may in a way mimic their in vivo behavior. In this novel in vitro 2D/3D model, the bioprinted cells show a more biological relevant behavior than normally cultured cells. Insights into the cell behavior after bioprinting may elucidate how to build improved in vitro models for BC research.

Correction: A new family of fullerene derivatives: fullerene–curcumin conjugates for biological and photovoltaic applications

Correction for ‘A new family of fullerene derivatives: fullerene–curcumin conjugates for biological and photovoltaic applications’ by Edison Castro et al., RSC Adv., 2018, 8, 41692–41698.

A new family of fullerene derivatives: Fullerene-curcumin conjugates for biological and photovoltaic applications

The synthesis and characterization of a family of [60]fullerocurcuminoids obtained via Bingel reactions is reported. The new C60 derivatives include curcumin and curcuminoids with a variety of end groups. Preliminary biological experiments show the potential activity of the compound containing a curcumin addend, which exhibits moderate anti-HIV-1 and radical scavenger properties, but no anti-cancer activity. In addition, the new fullerocurcuminoids exhibit HOMO/LUMO energy levels that are reasonably matched with those of perovskites and when they were tested in perovskite solar cells (PSCs) as the electron transporting material (ETM), photoconversion efficiencies ranging from 14.04%-14.95% were obtained, whereas a value of 16.23% was obtained for [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) based devices.

Pyronaridine exerts potent cytotoxicity on human breast and hematological cancer cells through induction of apoptosis

The potent antimalarial drug pyronaridine (PND) was tested for its potential as an anticancer drug. After exposing cancerous (17) and non-cancerous (2) cells to PND for 72 hr, PND was found to exhibit consistent and potent cytotoxic activity at low micromolar (μM) concentrations that ranged from 1.6 μM to 9.4 μM. Moreover, PND exerted a significant selective cytotoxicity index (SCI) on five out of seven breast cancer cell lines tested, with favorable values of 2.5 to 4.4, as compared with the non-cancerous breast MCF-10A cell line. By using the same comparison, PND exhibited a significant SCI on three out of four leukemia/lymphoma cell lines with promising values of 3.3 to 3.5. One breast cancer and one leukemia cell line were tested further in order to determine the likely mode of action of PND. PND was found to consistently elicit phosphatidylserine externalization, mitochondrial depolarization, and DNA fragmentation, in both the triple negative MDA-MB-231 breast cancer and HL-60 leukemia cell lines. In addition, PND treatment altered cell cycle progression in both cancer cells. Subsequent DNA mobility-shift assays, UV-Visible spectroscopic titrations, and circular dichroism (CD) experiments revealed that PND intercalates with DNA. The findings presented in this study indicates that PND induces apoptosis and interfered with cell cycle progression of cancer cell lines and these results indicate that this drug has the potential as a repurposed drug for cancer therapy.

Poly(ADP-ribose) polymerase-1 silences retroviruses independently of viral DNA integration or heterochromatin formation

PARP-1 silences retrotransposons in Drosophila, through heterochromatin maintenance, and integrated retroviruses in chicken. Here, we determined the role of viral DNA integration and cellular heterochromatin in PARP-1-mediated retroviral silencing using HIV-1-derived lentiviral vectors and Rous-associated virus type 1 (RAV-1) as models. Analysis of the infection of PARP-1 knockout and control cells with HIV-1 harbouring WT integrase, in the presence or absence of an integrase inhibitor, or catalytic-dead mutant integrase indicated that silencing does not require viral DNA integration. The mechanism involves the catalytic activity of histone deacetylases but not that of PARP-1. In contrast to Drosophila, lack of PARP-1 in avian cells did not affect chromatin compaction globally or at the RAV-1 provirus, or the cellular levels of histone H3 N-terminal acetylated or Lys27 trimethylated, as indicated by micrococcal nuclease accessibility and immunoblot assays. Therefore, PARP-1 represses retroviruses prior to viral DNA integration by mechanisms involving histone deacetylases but not heterochromatin formation.