Isoindolo[2,1-c]benzo[1,2,4]triazines: a new ring system with antiproliferative activity

A series of isoindolo-benzo-triazines of type 4 was obtained by diazotization of 2-(2-aminoaryl)-1-cyanoisoindoles 3a-j. All the synthesized derivatives were screened by the National Cancer Institute (NCI, Bethesda, USA), for in vitro antitumor activity against a 3-human cancer cell line panel consisting of MCF7 (breast), NCI-H460 (lung), and SF-268 (CNS). Derivatives 4a, f, i, j were selected to be evaluated in the full panel of about 50 human tumor cell lines derived from nine human cancer cell types and showed antiproliferative activity generally in the micromolar range. The most sensitive cell lines were: MOLT-4 and SR of the leukemia subpanel, A549/ATCC and EKVX of the nonsmall cell lung subpanel, COLO-205 of the colon cancer subpanel, LOX IMVI of the Melanoma subpanel, OVCAR-8 of the ovarian cancer subpanel, and MCF7, BT-549 of the breast cancer subpanel.     

Enzymatic transesterification monitored by an easy-to-use Fourier transform infrared spectroscopy method

Transesterification of triglycerides with short chain alcohols is the key reaction in biodiesel production, in addition to other applications in chemical synthesis. However, it is crucial to optimize reaction conditions to make enzymatic transesterification a cost-effective and competitive process. In this work, a new, easy Fourier transform infrared (FTIR) spectroscopic approach for monitoring the transesterification reaction is reported and compared with a gas-chromatographic method. The concentration of the total methyl esters in the reaction mixture is determined from the peak intensity at ∼1435 cm^–1 in the second derivatives of the FTIR absorption spectra using a linear regression calibration. Interestingly, we found that the use of second derivatives allows an accurate determination of the methyl esters without the interference of free fatty acids. Moreover, information on substrate hydrolysis can be obtained within the same measurement by the infrared absorption at ∼1709 cm^–1. We applied this approach to monitor methanolysis and hydrolysis reactions catalyzed by different commercial lipases, which displayed different sensitivities to methanol inhibition. Therefore, the FTIR approach reported in this work represents a rapid, inexpensive, and accurate method to monitor enzymatic transesterification, requiring very limited sample preparation and a simple statistical analysis of the spectroscopic data.     

Human pluripotent stem cells identify molecular targets of trisomy 12 in chronic lymphocytic leukemia patients

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Inhibition of PARP activity by PJ‐34 leads to growth impairment and cell death associated with aberrant mitotic pattern and nucleolar actin accumulation in M14 melanoma cell line

The capability of PARP activity inhibitors to prevent DNA damage recovery suggested the use of these drugs as chemo‐ and radio‐sensitisers for cancer therapy. Our research, carried out on cultured human M14 melanoma cells, was aimed to examine if PJ‐34, a potent PARP activity inhibitor of second generation, was per se able to affect the viability of these cancer cells without any DNA damaging agents. Using time‐lapse videomicroscopy, we evidenced that 10 µM PJ‐34 treatment induced severe mitotic defects leading to dramatic reduction of cell proliferation and to cell death. PJ‐34 cytotoxic effect was further confirmed by analysis of cell viability and clonogenic assay. Absence of canonic apoptosis markers allowed us to exclude this kind of cell death. No single and/or double stranded DNA damage was evidenced. Immunofluorescence analysis showed an aberrant mitotic scenario in several cells and subsequent multinucleation suggesting an atypical way for cells to die: the mitotic catastrophe. The detection of aberrant accumulation of polymerised actin inside the nucleolus was noteworthy. Taken toghether, our results demonstrate that, targeting PARP activity by PJ‐34, cancer cell survival is affected independently of DNA damage repair. Two findings are remarkable: (a) cisplatin concentration can be reduced by three quarters if it is followed by treatment with 10 µM PJ‐34 for 24 h to obtain the same citotoxic effect; (b) effects dependent on PJ‐34 treatment are reversible. Our data suggest that, to reduce the harm done to non‐tumour cells during chemotherapy with cisplatin, the latter could be coupled with PJ‐34 treatment. J. Cell. Physiol. 222: 401–410, 2010. © 2009 Wiley‐Liss, Inc.     

Floral abnormalities in field grown “Tigrina” plants from xHaynaldoticum sardoum Meletti et Onnis (Gramineae)

A ‘tigrina’ mutant stock of xHaynaldoticum sardoum Meletti et Onnis grown under field conditions produced high frequency spikes with abnormal stamens and pistils. The abnormalities occurred mostly in the stamens, which frequently changed to either pseudoovaries, or leaf-shaped structures or, in extreme cases, did not form at all. The developmental abnormalities of the stamens resulted in male sterility in the whole or in part of the spike. It is proposed that the “tigrina” status changes the physiology of the plant (e.g. photosynthetic activity) in such a way that it responds with floral abnormalities brought about by environmental conditions which permit normal flower development in control (non-mutant) plants.     

High Sensitivity of Glutamate Uptake to Extracellular Free Arachidonic Acid Levels in Rat Cortical Synaptosomes and Astrocytes

By using both synaptosomes and cultured astrocytes from rat cerebral cortex, we have investigated the inhibitory action of arachidonic acid on the high-affinity glutamate uptake systems, focusing on the possible physiological significance of this mechanism. Application of arachidonic acid (1-100 microM) to either preparation leads to fast (within 30 s) and largely reversible reduction in the uptake rate. When either melittin (0.2-1 microgram/ml), a phospholipase A2 activator, or thimerosal (50-200 microM), which inhibits fatty acid reacylation in phospholipids, is applied to astrocytes, both an enhancement in extracellular free arachidonate and a reduction in glutamate uptake are seen. The two effects display similar dose dependency and time course. In particular, 10% uptake inhibition correlates with 30% elevation in free arachidonate, whereas inhibition greater than or equal to 60% is paralleled by threefold stimulation of arachidonate release. In the presence of albumin (1-10 mg/ml), a free fatty acid-binding protein, inhibition by either melittin, thimerosal, or arachidonic acid is prevented and an enhancement of glutamate uptake above the control levels is observed. Our data show that neuronal and glial glutamate transport systems are highly sensitive to changes in extracellular free arachidonate levels and suggest that uptake inhibition may be a relevant mechanism in the action of arachidonic acid at glutamatergic synapses.     

A computer model of intermediate cerebellum dynamic operations in motor control

An intermediate cerebellum theoretical model for processing central programming discharges and muscle force signals is described which can perform a correct motor task under different peripheral perturbations (loads). An indispensable condition is that the simulated interpositus nucleus cells controlling a given effector (muscle) are inhibited by impulses coming from that effector (negative feedback from muscle force detectors). The hypothesis is proposed that the intermediate cerebellum can act via the rubrospinal tract as an interface between programming and executing motor structures.