Synthesis,biological evaluation and molecular docking studies of new amides of 4-bromothiocolchicine as anticancer agents

Colchicine is the major alkaloid isolated from the plant Colchicum autumnale, which shows strong therapeutic effects towards different types of cancer. However, due to the toxicity of colchicine towards normal cells its application is limited. To address this issue we synthesized a series of seven triple-modified 4-bromothiocolchicine analogues with amide moieties. These novel derivatives were active in the nanomolar range against several different cancer cell lines and primary acute lymphoblastic leukemia cells, specifically compounds: 5–9 against primary ALL-5 (IC₅₀ = 5.3–14 nM), 5, 7–9 against A549 (IC₅₀ = 10 nM), 5, 7–9 against MCF-7 (IC₅₀ = 11 nM), 5–9 against LoVo (IC₅₀ = 7–12 nM), and 5, 7–9 against LoVo/DX (IC₅₀ = 48–87 nM). These IC₅₀ values were lower than those obtained for unmodified colchicine and common anticancer drugs such as doxorubicin and cisplatin. Further studies revealed that colchicine and selected analogues induced characteristics of apoptotic cell death but manifested their effects in different phases of the cell cycle in MCF-7 versus ALL-5 cells. Specifically, while colchicine and the studied derivatives arrested MCF-7 cells in mitosis, very little mitotically arrested ALL-5 cells were observed, suggesting effects were manifest instead in interphase. We also developed an in silico model of the mode of binding of these compounds to their primary target, β-tubulin. We conducted a correlation analysis (linear regression) between the calculated binding energies of colchicine derivatives and their anti-proliferative activity, and determined that the obtained correlation coefficients strongly depend on the type of cells used.     

Speculations on the role of the microtubule network in glucocorticoid receptor signaling

The glucocorticoid receptor (GR) is an important player in the life of a cell. This is underlined by a cohort of protein and nucleic acid structures interacting with the GR. Among many issues surrounding GR activity that are under active investigation, the role of microtubules (MTs) is still unclear. This article aims to evaluate the ayes and noes in favor of microtubule importance and then form a hypothesis on their function in GR activity.     

Electrical Conductance of Cell-to-Cell Junctions and the Cytoskeleton of Plant Cells

In the submerged trichomes of floating-moss (Salvinia auriculataAubl.) and the roots of the higher water plant Trianea bogotensisKarst., the dependence of the electrical resistance of intercellular junctions on the presence of the agents that destroy microfilaments (cytochalasin B) and microtubules (colchicine) was investigated using the microelectrode technique. The resistance of the junctions (R _c) was estimated taking into account the input resistance and the coefficient of intercellular electrical communication. Should the cells be connected via symplast, R _cwill describe the resistance of plasmodesmata. Cytochalasin B (3–30 g/ml) reversibly changed R _cduring the first minutes after application. The extent of the change depended on the concentration of the inhibitor; its character of action depended on the initial strength of intercellular communication. When the initial conductance of the contact was high, cytochalasin B elevated the resistance; when it was low, the inhibitor decreased it. In all the experiments, cytochalasin B reduced the input resistance (R _i) that suggests the dependence of plasma membrane resistance on actin cytoskeleton. The effect of colchicine (0.1–1.0 mM) on R _iand R _cwas observed only when the cellular membrane was hyperpolarized or after a prolonged action of the inhibitor (for about 0.5 h). It was concluded that the electrical conductance of plasmodesmata and plasma membrane depended on the state of actin cytoskeleton. A complex and probably mediated interaction of microtubules with the processes affecting these characteristics of the cells was suggested.     

D4 Dopamine and Metabotropic Glutamate Receptors in Cerebral Cortex and Striatum in Rat Brain

The characterization of the functional interactions between the metabotropic glutamate receptors (mGluR) and the dopaminergic (DR) receptors in the corticostriatal projections may provide a possible interpretation of synaptic events in the basal ganglia. It has been suggested that presynaptic D2-type receptor located on glutamatergic corticostriatal neurons regulates the release of glutamate. In a first approach we have studied the cellular distribution of the D4R and the mGluRs in cerebral cortex and striatum employing immunocytochemistry. D4R positive neurons were particularly numerous in medial prefrontal cortex mainly occupying layers II and III. An even distribution was found on small round-shaped neurons in the striatum. Group I mGluR1-like immunoreactivity (mGluR1-LI) was found in medial and deep layers of the cerebral cortex while group III mGluR4a labeled more superficial layers; group II mGluR2/3 signal was intense on fine fibers with a punctate appearance. In the striatum, mGluR1 and mGluR2/3 stained mainly fibers while mGluR4a labeled round shaped cell bodies. After lateral ventricular injection of colchicine, an axonal transport and firing activity blocker, D4R labeling significantly increased in cerebral cortex and decreased in the striatum. mGluR1 and mGluR4a signal decreased in cerebral cortex and only mGluR4a signal decreased in the striatum. These results support previous reports indicating a presynaptic localization of D4R in the striatum. In contrast, striatal mGluR1 appears to be a postsynaptic receptor probably synthesized in situ. Our results do not support the hypothesis of a colocalization of D4 receptor and one or more of the metabotropic glutamatergic receptors studied here.     

LOCALIZATION OF CA2+-STIMULATED ATPASE IN THE COCCOLITH-PRODUCING COMPARTMENT OF CELLS OF PLEUROCHRYSIS SP. (PRYMNESIOPHYCEAE)1

Cell homogenates of Pleurochrysis sp. (CCMP299) were fractionated by means of sucrose gradients. Ca²⁺-stimulated ATPase (EC 3.6.1.3., ATP phosphohydrolase) was associated primarily with the plasma membrane, Golgi, and high density (1.21 g·cm^?3) membranous structures. Ca²⁺-stimulated ATPase was highly enriched in the latter. Based on treatments with Triton X-100 and NBD ceramide, we conclude that the high-density structures were membrane-delimited organelles. These vesicle-like organelles contained complex polysaccharides, a high concentration of calcium, and, upon microscopic examination, structures resembling coccoliths. These findings are consistent with observations on the known composition of coccoliths and the presumed mineralizing function of the sub-cellular coccolith-producing compartment. The high-density vesicles were linked to the Golgi by means of colchicine-sensitive materials, presumably microtubules. These data and prior ultrastructural observations by other investigators indicating vectorial assembly and secretion suggest that the subcellular movement of the newly formed coccoliths may be directed and/or powered by colchicine-sensitive cytoskeletal elements. We interpret the data to mean that the high-density vesicles represent the coccolith-producing compartment previously observed by others in electron micrographs.     

氮离子注入对蒙古黄芪多倍体诱导的影响

利用二倍体蒙古黄芪种子为材料,以低能氮离子束为诱变源,将化学诱导与物理诱变相结合,探索出一套高效的多倍体诱导新方法。研究结果表明：氮离子注入种子后表现出明显的生物学效应;氮离子注入与秋水仙素联合诱导黄芪多倍体的效果很明显。氮离子注入剂量为2.6×10¹⁶ N⁺/cm²,秋水仙素浓度为100 mg·L^-1,培养5 d诱导率最高为44.4%;氮离子注入剂量为5.2×10¹⁶ N⁺/cm², 秋水仙素浓度为150 mg·L^-1,培养10d的诱导率最高为46.2%;二者均高于对照组秋水仙素浓度为100 mg·L^-1培养15 d的最高诱导率13.9%。利用细胞染色体计数鉴定多倍体为四倍体。     

Colchicine Treatment Differently Affects Releasable Thyrotropin-Releasing Hormone (TRH) Pools in the Hypothalamic Paraventricular Nucleus (PVN) and the Median Eminence (ME)

1. Hypophysiotropic thyrotropin-releasing hormone (TRH) is synthesized in the hypothalamic paraventricular nucleus (PVN) and transported to the median eminence (ME) where it enters the hypophyseal portal blood. TRH in the ME is situated exclusively in nerve terminals, whereas TRH in the PVN and septum is of extrinsic (nerve terminals) as well as intrinsic (perikarya) origin. 2. To determine the source and possible differential regulation of TRH release from these structures, we blocked TRH axonal delivery by i.c.v. administration of colchicine into the lateral cerebral ventricle of euthyroid or hypothyroid rats in doses of 7.5 μg or 7.5, 75 and 100 μg, respectively, two days prior to the evaluation of the TRH secretion from the PVN, ME and the septum in vitro. 3. In euthyroid rats a low dose of colchicine did not significantly affect plasma TSH. The secretory response to both ethanol in an isosmolar medium and a high K⁺ in the ME as well as the PVN explants was well preserved. However, colchicine treatment resulted in the significant increase of basal secretion of TRH from the PVN. 4. Hypothyroidism induced by 200 mg/l methimazole in drinking water for two weeks resulted in growth arrest, elevated plasma thyrotropin and decreased TRH content in the PVN and the ME. Colchicine partially decreased elevated plasma thyrotropin and increased the TRH content in the PVN and its basal release in vitro which was independent of extracellular Ca²⁺. Interestingly, a TRH release from the PVN could not be further stimulated either by K⁺ membrane depolarization or by ethanol. TRH responsiveness to the stimulation remained unaffected in the ME. The effect of colchicine on the septal TRH secretion was intermediate between the effect observed in the PVN and the ME. 5. In conclusion, the absence of a TRH secretory response to stimuli in the PVN after colchicine disruption of the microtubules and Golgi system suggests that stimulated TRH release observed from the PVN explants in vitro occurs from nerve terminals projecting to the PVN from other brain regions. The independence from extracellular calcium implies that TRH released under the non-stimulating conditions occurs most likely via the constitutive secretory pathway from dendrites and/or perikarya. Regulation of septal TRH is markedly different from the hypophysiotropic one. An erratum to this article is available at .     

秋水仙素诱导七里香多倍体

以不同浓度（0．02％、0．04％、0．08％、0．16％）秋水仙素溶液与二甲基亚砜和丙草胺的体积混合比为2000：10：1的溶液诱导七里香种子萌发苗1-3d的结果表明,所有处理均得到七里香多倍体,其中以秋水仙素浓度为0．08％的混合液处理3d的诱导效果最好,多倍体诱导率迭36．7％。     

授粉后秋水仙素处理对大青杨子代生长性状的影响

为东北林区选育出速生、优质、抗逆性强的杨树新品种,本研究采用秋水仙素溶液处理授粉后的大青杨雌花序,分析诱导后大青杨子代植株光合特性、生长量和叶形态指标的差异。结果表明：(1)雌花序授粉后24 h开始处理,秋水仙素4 g·L^-1处理12 h后大青杨子代植株的苗高、地径均最大,且与对照差异显著;(2)雌花序授粉后24h开始处理,秋水仙素处理12 h后大青杨子代植株蒸腾速率最小,对照蒸腾速率最大;雌花序授粉后24 h开始处理,子代植株气孔导度最小,36 h后开始处理所得的子代植株气孔导度最大;雌花序授粉后12 h开始处理子代植株水分利用效率最大,对照最小。(3)子代植株生长量指标（苗高、地径）与叶形态指标以及气孔导度、胞间CO₂浓度、蒸腾速率、水分利用效率相关显著。     

In vitro induction of tetraploid in pomegranate (Punica granatum)

Tetraploid plants were obtained in pomegranate (Punica granatum L. var. `Nana') by colchicine treatment of shoots propagated in vitro. Shoots cultured on MS medium supplemented with 10 mg l^–1 colchicine, 1.0 mg l^–1 BA and 0.1 mg l^–1 NAA for 30 days produced tetraploids at a high frequency of 20%. No tetraploids were detected by treating the shoots in 5000 mg l^–1 colchicine for 114 h. Shoots treated by 5000 mg l^–1 colchicine for 96 h produced three morphological mutants with narrow leaves, which were later confirmed as mixoploids that separated into diploids and tetraploids after further subculture. In vitro tetraploid plants had shorter roots, wider and shorter leaves than the diploid ones. Tetraploid pomegranate plants grew and flowered normally in pots, but possessed flowers with increased diameter and decreased length compared to diploids. The number of pollen grains per anther was higher in tetraploids, but the viability of pollen decreased significantly.