A Comparative Analysis of the In Vitro Anticancer Activity of Iridium(III) {η5-C5Me4R} Complexes with Variable R Groups

Piano-stool iridium complexes based on the pentamethylcyclopentadienyl ligand (Cp*) have been intensively investigated as anticancer drug candidates and hold much promise in this setting. A systematic study aimed at outlining the effect of Cp* mono-derivatization on the antiproliferative activity is presented here. Thus, the dinuclear complexes [Ir(η5-C5Me4R)Cl(μ-Cl)]2 (R = Me, 1a; R = H, 1b; R = Pr, 1c; R = 4-C6H4F, 1d; R = 4-C6H4OH, 1e), their 2-phenylpyridyl mononuclear derivatives [Ir(η5-C5Me4R)(kN,kCPhPy)Cl] (2a–d), and the dimethylsulfoxide complex [Ir{h5-C5Me4(4-C6H4OH)}Cl2(κS-Me2S=O)] (3) were synthesized, structurally characterized, and assessed for their cytotoxicity towards a panel of six human and rodent cancer cell lines (mouse melanoma, B16; rat glioma, C6; breast adenocarcinoma, MCF-7; colorectal carcinoma, SW620 and HCT116; ovarian carcinoma, A2780) and one primary, human fetal lung fibroblast cell line (MRC5). Complexes 2b (R = H) and 2d (4-C6H4F) emerged as the most active ones and were selected for further investigation. They did not affect the viability of primary mouse peritoneal cells, and their tumoricidal action arises from the combined influence on cellular proliferation, apoptosis and senescence. The latter is triggered by mitochondrial failure and production of reactive oxygen and nitrogen species.

Morphological and Microscopical Characteristics of Murdannia bracteata (C.B.Clarke) J.K.Morton ex D.Y.Hong

Morphological and microscopical characteristics of “Co ruoi la bac” collected in Nam Dinh province were studied. Results have identified the scientific name of the plant as Murdannia bracteata (family Commelinaceae). Besides, the microscopical characteristics and powder microscopy of leaf and stem of M. bracteata species were established. Specifically, the plant’s leaf and stem are characterized by pale violet corolla, oval bracts and needle shape calcium oxalate crystals converging or single in the soft tissue of the leaf; the herbal powder has twisted vascular grafts, unicellular hairs,… Keywords: Murdannia bracteata, M. bracteata, Murdannia bracteata (C.B.Clarke) J.K.Morton ex D.Y.Hong, Commelinaceae, morphological characteristics, microscopical characteristic References [1] M. D. O. Pellegrini, R. B. Faden, R. F. D. Almeida, Taxonomic Revision of Neotropical Murdannia Royle (Commelinaceae), PhytoKeys, Vol. 74, 2016, pp. 35-78, https://doi.org/10.3897/phytokeys.74.9835.[2] R. B. Faden, K. E. Inman, Leaf Anatomy of The African Genera of Commelinaceae: Anthericopsis and Murdannia, The Biodiversity of African Plants, 1996, pp. 464-471, https://doi.org/10.1007/978-94-009-0285-558.[3] M. C. Naik, B. R. P. Rao, A New Species of Dewflower Murdannia Sanjappae (Commelinaceae) from Andaman Islands, India, Journal of Threatened Taxa, Vol. 9, No. 11, 2017, pp. 10909-10913, http://doi.org/10.11609/jott.3341.9.11.10909-10913.[4] V. V. Chi, Dictionary of Medicinal Plants in Vietnam, Medical Publishing House, Hanoi, 2012 (in Vietnamese).[5] P. H. Ho, An Illustrated Flora of Vietnam, Youth Publishing House, Ho Chi Minh City, 2003 (in Vietnamese).[6] M. Betti, A. Minelli, B. Canonico, P. Castaldo, S. Magi, M. Aisa, F. Galli, Antiproliferative Effects of Tocopherols (Vitamin E) on Murine Glioma C6 Cells: Homologue-specific Control of PKC/ERK and Cyclin Signaling, Free Radical Biology and Medicine, Vol. 41, No. 3, 2006,pp. 464-472, http://doi.org/10.1016/j.freeradbiomed.2006.04.012.[7] N. N. Thin, Plant Research Methods, Education Publishing House, Hanoi, 2006 (in Vietnamese).[8] V. D. Loi, L. T. T. Huong, Texbook: Practical Botany - Pharmacognosy - Traditional Medicine, Hanoi National University Publishing House, Hanoi, 2017 (in Vietnamese).

Effects of lyoprotectants on long-term stability and transfection efficacy of lyophilized poly(lactide-co-glycolide)-graft-polyethylenimine/plasmid DNA polyplexes

Aim: We investigated the effect of lyoprotectants on the long-term stability and transfection efficiency of lyophilized (Lyo.) polyplexes prepared from poly(lactide-co-glycolide)-graft-polyethylenimine (PgP) and plasmid DNA encoding green fluorescent protein (pGFP). Materials & methods: Lyo. PgP/pGFP polyplexes prepared with/without lyoprotectants were stored at -20°C over 6 months. Polyplex stability was analyzed by gel electrophoresis and heparin competition assay. Transfection efficiency and cytotoxicity were evaluated in rat glioma (C6) cells in medium containing 10% serum. Results: Lyo. PgP/pGFP polyplexes prepared with 5% sucrose as a lyoprotectant remained stable up to 6 months and retained transfection efficiency up to 4 months. Conclusion: Lyo. PgP-based polyplexes retain bioactivity during extended storage, potentially enabling transport to remote regions and less stable settings, increasing access to life-changing gene therapy.

Xanthohumol-Induced Rat Glioma C6 Cells Death by Triggering Mitochondrial Stress

AIM: To investigate the underlying mechanisms of xanthohumol (XN) on the proliferation inhibition and death of C6 glioma cells. METHODS: To determine the effects of XN on C6 cells, cell proliferation and mortality after XN treatment were assessed by SRB assay and trypan blue assay respectively. Apoptotic rates were evaluated by flowcytometry after Annexin V-FITC/PI double staining. The influence of XN on the activity of caspase-3 was determined by Western blot (WB); and nuclear transposition of apoptosis-inducing factor (AIF) was tested by immunocytochemistry and WB. By MitoSOXTM staining, the mitochondrial ROS were detected. Mitochondrial function was also tested by MTT assay (content of succinic dehydrogenase), flow cytometry (mitochondrial membrane potential (MMP)—JC-1 staining; mitochondrial abundance—mito-Tracker green), immunofluorescence (MMP—JC-1 staining; mitochondrial morphology—mito-Tracker green), WB (mitochondrial fusion-fission protein—OPA1, mfn2, and DRP1; mitophagy-related proteins—Pink1, Parkin, LC3B, and P62), and high-performance liquid chromatography (HPLC) (energy charge). Finally, mitochondrial protein homeostasis of C6 cells after XN treatment with and without LONP1 inhibitor bortezomib was investigated by trypan blue assay (proliferative activity and mortality) and WB (mitochondrial protease LONP1). All cell morphology images were taken by a Leica Microsystems microscope. RESULTS: XN could lead to proliferation inhibition and death of C6 cells in a time- and dose-dependent manner and induce apoptosis of C6 cells through the AIF pathway. After long incubation of XN, mitochondria of C6 cells were seriously impaired, and mitochondria had a diffuse morphology and mitochondrial ROS were increased. The content of succinic dehydrogenase per cell was significantly decreased after XN insults of 24, 48, and 72 h. The energy charge was weakened after XN insult of 24 h. Furthermore, the MMP and mitochondrial abundance were significantly decreased; the protein expression levels of OPA1, mfn2, and DRP1 were down-regulated; and the protein expression levels of Pink1, Parkin, LC3B-II/LC3B-I, and p62 were up-regulated in long XN incubation times (24, 48, and 72 h). XN incubation with bortezomib for 48 h resulted in lower proliferative activity and higher mortality of C6 cells and caused the cell to have visible vacuoles. Moreover, the protein expression levels of LONP1 was up-regulated gradually as XN treatment time increased. CONCLUSION: These data supported that XN could induce AIF pathway apoptosis of the rat glioma C6 cells by affecting the mitochondria.

Glioma C6 perivascular changes of invasion structural parameters variation (research study).

A comparative study of the structural characteristics of microvessels with a perivascular arrangement of tumor cells and microvessels with normal structure located in the peritumoral zones of an intracranially implanted glioblastoma ("glioma C6") was conducted. The study was performed on rats. Morphometric method was used to determine the area, internal diameter and length of microvessels for 21 days after the introduction of tumor cells into the brain of rats. Changes in the structure of microvessels with glioblastoma cells were registered throughout the entire observation period. The active role of perivascularly located tumor cells in the transformation of the structure and properties of microvessels involved in the process of glioblastoma invasion into brain tissue is considered. Key words: glioblastoma, microvessels, morphometry, peritumoral zones.

α-Conotoxins and α-Cobratoxin Promote, while Lipoxygenase and Cyclooxygenase Inhibitors Suppress the Proliferation of Glioma C6 Cells

Among the brain tumors, glioma is the most common. In general, different biochemical mechanisms, involving nicotinic acetylcholine receptors (nAChRs) and the arachidonic acid cascade are involved in oncogenesis. Although the engagement of the latter in survival and proliferation of rat C6 glioma has been shown, there are practically no data about the presence and the role of nAChRs in C6 cells. In this work we studied the effects of nAChR antagonists, marine snail α-conotoxins and snake α-cobratoxin, on the survival and proliferation of C6 glioma cells. The effects of the lipoxygenase and cyclooxygenase inhibitors either alone or together with α-conotoxins and α-cobratoxin were studied in parallel. It was found that α-conotoxins and α-cobratoxin promoted the proliferation of C6 glioma cells, while nicotine had practically no effect at concentrations below 1 µL/mL. Nordihydroguaiaretic acid, a nonspecific lipoxygenase inhibitor, and baicalein, a 12-lipoxygenase inhibitor, exerted antiproliferative and cytotoxic effects on C6 cells. nAChR inhibitors weaken this effect after 24 h cultivation but produced no effects at longer times. Quantitative real-time polymerase chain reaction showed that mRNA for α4, α7, β2 and β4 subunits of nAChR were expressed in C6 glioma cells. This is the first indication for involvement of nAChRs in mechanisms of glioma cell proliferation.

Possibilities of small-size glioblastoma visualization by PET-CT with 11C-choline (experimental study)

Introduction. The minimum size of malignant brain tumors detected by positron emission and computed tomography (PET-CT) exceeds 6-7 mm. One of the ways to increase the sensitivity of PET-CT in detecting of malignant brain tumors is to increase the administered activity of the radiopharmaceutical 11C-choline.Purpose & tasks. The aim of the study was to experimentally study the possibility of obtaining a small-size glioblastoma (GB) images (up to 4 mm) by PET-CT with the 11C-choline.Materials and methods. The study was performed on 24 rats with implanted intracerebral tumor «Glioma C6» (glioblastoma). Animals underwent magnetic resonance imaging (MRI) with contrast enhancement (CE) and PET-CT with 11C-choline for 21 days after tumor transplantation.Results. It was shown that using two methods: MRI with CE and PET-CT with 11C-choline, a glioblastoma up to 4 mm can be convincingly visualized.Conclusion. The data obtained can be crucial for early detection of glioblastoma, justification of treatment tactics, evaluation of the treatment effectiveness and prediction the outcome of the disease.