Involvement of Cannabinoid Receptors and Adenosine A2B Receptor in Enhanced Migration of Lung Cancer A549 Cells Induced by γ-Ray Irradiation

Residual cancer cells after radiation therapy may acquire malignant phenotypes such as enhanced motility and migration ability, and therefore it is important to identify targets for preventing radiation-induced malignancy in order to increase the effectiveness of radiotherapy. G-Protein-coupled receptors (GPCRs) such as adenosine A2B receptor and cannabinoid receptors (CB1, CB2, and GPR55) may be involved, as they are known to have roles in proliferation, invasion, migration and tumor growth. In this study, we investigated the involvement of A2B and cannabinoid receptors in γ-radiation-induced enhancement of cell migration and actin remodeling, as well as the involvement of cannabinoid receptors in cell migration enhancement via activation of A2B receptor in human lung cancer A549 cells. Antagonists or knockdown of A2B, CB1, CB2, or GPR55 receptor suppressed γ-radiation-induced cell migration and actin remodeling. Furthermore, BAY60-6583 (an A2B receptor-specific agonist) enhanced cell migration and actin remodeling in A549 cells, and this enhancement was suppressed by antagonists or knockdown of CB2 or GPR55, though not CB1 receptor. Our results indicate that A2B receptors and cannabinoid CB1, CB2, and GPR55 receptors all contribute to γ-radiation-induced acquisition of malignant phenotypes, and in particular that interactions of A2B receptor and cannabinoid CB2 and GPR55 receptors play a role in promoting cell migration and actin remodeling. A2B receptor-cannabinoid receptor pathways may be promising targets for blocking the appearance of malignant phenotypes during radiotherapy of lung cancer.

Glue embolization for gastroduodenal ulcer bleeding: contribution to hemodynamics and healing process

BACKGROUND

Although the morbidity of bowel ischemic events after glue embolization has been suggested, a causal relationship between glue and ischemia has not been clearly established.

PURPOSE

To evaluate the efficiency and safety of transcatheter arterial embolization with n-butyl cyanoacrylate (NBCA-TAE) for upper gastrointestinal hemorrhage (GIH).

MATERIAL AND METHODS

Between October 2006 and October 2012, 21 patients with upper GIH underwent NBCA-TAE, and endoscopic data were obtained within 30 days of follow-up. Shock index prior to and immediately after NBCA-TAE were compared to determine changes in hemodynamics. Days to Forrest type III, as assessed by follow-up endoscopy, was used as an indicator of the healing process. Other clinical outcomes included days for starting ingestion and for hospital discharge.

RESULTS

Sixteen gastric and five duodenal ulcers, classified into Forrest type I, were treated. Immediate hemostasis was achieved in all the patients, and no re-bleeding occurred within the follow-up period. Shock index significantly (P < 0.001) improved from before (0.99 ± 0.076) to immediately after NBCA-TAE (0.67 ± 0.038). Sequential mucosal healing processes were observed in all the patients, and the number of days to Forrest type III was 9.6 ± 7.1. The number of days for starting ingestion and hospital discharge was 9.0 ± 4.5 and 15 ± 7.7 days, respectively.

CONCLUSION

NBCA-TAE is an effective and safe method for the control of nonvariceal upper GIH, in terms of contribution to hemodynamics and healing process of the gastroduodenal mucosa.

Polyclonal B cell chronic lymphoproliferative disease with hairy cell morphology: a case report and clonal studies

We describe a patient who has a chronic polyclonal B lymphocyte proliferation with a hairy-cell appearance. A 48-year-old Japanese woman with marked splenomegaly, systemic lymphadenopathy, and leukocytosis was referred to out hospital. Laboratory examination revealed marked polyclonal IgG hypergammaglobulinemia. Morphologic examination of the patient's peripheral blood, including May-Giemsa staining and scanning electron microscopy, showed a monotonous proliferation of hairy-appearing mature lymphocytes. An immunophenotypic study revealed an expansion of cells with mature B cell antigens positive for CD11c; however, light-chain restriction was not seen. The lack of both immuno-globulin heavy-chain and T cell receptor gene rearrangements by Southern blot analysis indicated the polyclonal nature of the proliferating B cells. This was confirmed further by a clonal analysis of the patient's lymphocytes using an X-chromosome-linked restriction fragment polymorphism within the X-linked phosphoglycerate kinase (PGK) gene. Since chronic B cell lymphoproliferation with a hairy cell appearance has not been described previously, this case might be extremely rare, and has important implication for the pathogenesis of mature B cell lymphoproliferative diseases, including hairy cell leukemia.

Vesicular monoamine uptake by digitonin-permeabilized PC12 cells: inhibitory effect of neuromodulators and drugs on the amine transport

Vesicular amine transport is crucial for activity of monoaminergic neurons since translocation of cytosolic amine to storage vesicles is required for both exocytotic release and reuptake of the neurotransmitter. We developed a convenient assay system for vesicular amine transport based on permeabilizing the plasma membrane of pheochromocytoma PC12 cells with digitonin at concentrations of 100 to 150 microM. Serotonin (5HT) is a better substrate than either epinephrine or norepinephrine in this assay system. In the presence of 2 mM ATP, 5HT uptake by the permeabilized cells increased linearly for at least 30 min at 25 degrees C, whereas without addition of exogenous ATP, 5HT uptake reached an apparent plateau after 20 min incubation. Reserpine (500 nM) completely blocked the ATP-dependent 5HT uptake in this system whereas nomifensine (10 microM) had no effect, indicating specificity for vesicular transport. Treatment of intact PC12 cells with AMP dose-dependently decreased 5HT uptake with an EC50 of 20-30 microM as measured after cell permeabilization. Treatment of the intact PC12 cells with forskolin and phorbol 12-myristate 13-acetate prior to permeabilization also down-regulated vesicular 5HT transport, whereas the addition of either of these agents into the reaction mixture for the amine uptake by already permeabilized cells did not alter the vesicular uptake activity. Thus, the system can be applied to studies on regulation of the vesicular amine transport by physiological signaling molecules, intracellular messengers, and drugs.

Effects of protein kinase inhibitors and protein phosphatase inhibitors on cyclic AMP-dependent down-regulation of vesicular monoamine transport in pheochromocytoma PC12 cells

Cyclic AMP down-regulates vesicular monoamine transport in PC12 cells and thereby decreased catecholamine reuptake from the extracellular fluid. We examined the effects of protein kinase inhibitors and protein phosphatase inhibitors on this cAMP action. Treatment of cells with a protein kinase inhibitor, K252a, increased vesicular amine transport and cellular amine uptake, thereby antagonizing the regulatory action of cAMP. In contrast, a protein phosphatase inhibitor, okadaic acid, had the opposite effect on the amine transport, i.e. it enhanced the cAMP action. These results suggest the involvement of a protein phosphorylation process in the cAMP-dependent modulation of vesicular monoamine transport.

Cyclic AMP-dependent modulation of vesicular monoamine transport in pheochromocytoma cells

Cyclic AMP (cAMP) is well known to enhance tyrosine hydroxylase activity in PC12 cells. We were able to demonstrate, however, that the cellular dopamine level in PC12 was lowered by dibutyryl cAMP. Furthermore, the decrease in the cellular level of dopamine was accompanied by about a 10-fold increase in the medium. The aim of this work was to elucidate the effect of cAMP on catecholamine transport. Dibutyryl cAMP did not induce exocytotic release of norepinephrine but rather inhibited its uptake. As with forskolin and cholera toxin, physiological signaling molecules such as vasoactive intestinal polypeptide (VIP) and AMP, for which PC12 cells are known to have receptors linked to activation of adenylate cyclase, also inhibited norepinephrine uptake. The inhibitory effects of dibutyryl cAMP, VIP, and AMP were dose dependent, and EC50 values were estimated to be 100 microM, 10 nM, and 1.0 microM, respectively. The inhibition profile of dibutyryl cAMP over the time course of norepinephrine uptake was biphasic: inhibition became clearly detectable after the cytosolic pool of norepinephrine had been saturated. This profile is similar to that of reserpine. Nomifensine, however, inhibited uptake at a rather constant rate throughout the entire time course. The ATP-dependent serotonin uptake by digitonin-permeabilized cells was lowered to approximately 50% that of the control by dibutyryl cAMP treatment before permeabilization, indicating inhibition of vesicular monoamine transport. This effect was also dependent on a dibutyryl cAMP concentration with an EC50 of < or = 100 microM.(ABSTRACT TRUNCATED AT 250 WORDS)