Tick salivary gland as potential natural source for the discovery of promising antitumor drug candidates

Nowadays, the relationship between cancer blood coagulation is well established. Regarding biodiversity and bioprospection, the tick biology has become quite attractive natural source for coagulation inhibitors, since its saliva has a very rich variety of bioactive molecules. For instance, a Kunitz-type FXa inhibitor, named Amblyomin-X, was found through transcriptome of the salivary gland of the Amblyomma cajennense. tick. This TFPI-like inhibitor, after obtained as recombinant protein, has presented anticoagulant, antigionenic, and antitumor properties. Although its effects on blood coagulation could be relevant for antitumor effect, Amblyomin-X acts by non-hemostatic mechanisms, such as proteasome inhibition and autophagy inhibition. Notably, cytotoxicity was not observed on non-tumor cells treated with this protein, suggesting some selectivity for tumor cells. Considering the current efforts in order to develop effective anticancer therapies, the findings presented in this review strongly suggest Amblyomin-X as a promising novel antitumor drug candidate. (C) 2015 Elsevier Masson SAS. All rights reserved.

Specific role of cytoplasmic dynein in the mechanism of action of an antitumor molecule, Amblyomin-X

The Kunitz-type recombinant protein, Amblyomin-X, is an antitumor recombinant molecule from a cDNA library prepared from the salivary glands of the tick Amblyomma cajennense. The primary target of this protein appears to be the proteasome. Amblyomin-X increased gene and protein expression of distinct subunits of the molecular motor dynein, which plays a key role in the intracellular transport. Herein, Amblyomin-X was specifically taken up by tumor cells through lipid-raft endocytic pathways, but not by fibroblasts. Moreover, dynein inhibitor, ciliobrevin A, decreased Amblyomin-X uptake by tumor cells. Furthermore, incubation of tumor cells with Amblyomin-X inhibited trypsin-like activity of the proteasome, which was restored upon pretreatment with ciliobrevin A. Only in tumor cells treated with Amblyomin-X, we identified proteins bounds to dynein that are related to aggresome formation, autophagy inhibition, and early and recycling endosome markers. In addition, Amblyomin-X was found to interact with dynein, increased Rab11A protein expression and Rab11A co-localization with the light intermediate chain 2 (LIC2) of dynein. Thereby, the results provide new insights on the antitumor mechanism of Amblyomin-X and reveal an unsuspected role of cytoplasmic dynein in its uptake, intracellular trafficking and pro-apoptotic action. (C) 2016 Published by Elsevier Inc

Amblyomin-X induces ER stress, mitochondrial dysfunction, and caspase activation in human melanoma and pancreatic tumor cell

During the last two decades, new insights into proteasome function and its role in several human diseases made it a potential therapeutic target. In this context, Amblyomin-X is a Kunitz-type FXa inhibitor similar to endogenous tissue factor pathway inhibitor (TFPI) and is a novel proteasome inhibitor. Herein, we have demonstrated Amblyomin-X cytotoxicity to different tumor cells lines such as pancreatic (Panc1, AsPC1BxPC3) and melanoma (SK-MEL-5 and SK-MEL-28). Of note, Amblyomin-X was not cytotoxic to normal human fibroblast cells. In addition, Amblyomin-X promoted accumulation of ER stress markers (GRP78 and GADD153) in sensitive (SK-MEL-28) and bortezomib-resistant (Mia-PaCa-2) tumor cells. The intracellular calcium concentration [Ca2+] (i) was slightly modulated in human tumor cells (SK-MEL-28 and Mia-PaCa-2) after 24 h of Amblyomin-X treatment. Furthermore, Amblyomin-X induced mitochondrial dysfunction, cytochrome-c release, PARP cleavage, and activation of caspase cascade in both human tumor (SK-MEL-28 and Mia-PaCa-2) cells. These investigations might help in further understanding of the antitumor properties of Amblyomin-X

Efecto de la estimulación eléctrica neuromuscular y de los ejercicios isotónicos en los músculos flexores y extensores de la rodilla en pacientes hemipléjicos / Effect of neuromuscular electrical stimulation and isotonic exercises in flexor and extensor muscles of knee of hemiplegic patients

Comprobar la fuerza muscular y la resistencia al movimiento de los músculos flexores y extensores de larodilla de los pacientes con espasticidad después del tratamiento con estimulación eléctrica neuromuscular (EENM) y ejercicios isotónicos. Pacientes y métodos. Los pacientes se dividieron en grupo 1 (EENM) y grupo 2 (ejercicios isotónicos). Su momentode fuerza muscular y la resistencia al movimiento de los músculos flexores y extensores de la rodilla se midieron mediante el dinamómetro isocinético, y el grado de espasticidad se midió mediante la escala modificada de Ashworth antes y después de diez sesiones. Resultados. No se observaron variaciones en las puntuaciones de la escala modificada de Ashworth.Se verificó un aumento del momento de fuerza de flexión en el grupo 1 (p = 0,041) y en el grupo 2 (p = 0,001). En el modo pasivo, el grupo 1 presentó una disminución de la resistencia al movimiento de flexión (p = 0,026), mientras que en el grupo 2 se verificó una disminución de la resistencia tanto al movimiento de flexión (p = 0,029) como al movimiento de extensión(p = 0,019). Conclusiones. Los dos recursos terapéuticos demostraron su eficacia sólo para el aumento de la fuerza de los músculos flexores. En la resistencia al movimiento, los ejercicios isotónicos fueron más eficaces porque fomentaron una disminuciónde la resistencia de los músculos flexores y extensores de la rodilla

To verify the muscular force and resistance to the movement of the flexor and extensor muscles of the knee of patients with spasticity after treatment with neuromuscular electrical stimulation (NMES) and isotonic exercises. Patients and methods. The patients this study were divided into group 1 (NMES) and group 2 (isotonic exercises). Their muscular torque and resistance to the movement of the flexor and extensor knee muscles were measured by the isokinetic dynamometer and thedegree of spasticity by the modified Ashworth scale before and after ten sessions. Results. Alterations in the scores of the modified Ashworth scale were not observed. An increase in the flexor torque in group 1 (p = 0.041) and in group 2 (p = 0.001)was verified. In the passive mode, group 1 presented a reduction of resistance to the flexion movement (p = 0.026), while in group 2, a reduction of resistance to both the flexion (p = 0,029) and extension movements (p = 0.019) was verified.Conclusions. The two therapeutical resources had their efficiency proven only for the increase of the force of the flexor muscles. The resistance to movement, the isotonic exercises were more effective because they promoted a reduction in the resistance of the flexor and extensor knee muscles