Polyamine catabolism: target for antiproliferative therapies in animals and stress tolerance strategies in plants

Metabolism of polyamines spermidine and spermine, and their diamine precursor, putrescine, has been a target for antineoplastic therapy since these naturally occurring alkyl amines were found essential for normal mammalian cell growth. Intracellular polyamine concentrations are maintained at a cell type-specific set point through the coordinated and highly regulated interplay between biosynthesis, transport, and catabolism. A correlation between regulation of cell proliferation and polyamine metabolism is described. In particular, polyamine catabolism involves copper-containing amine oxidases and FAD-dependent polyamine oxidases. Several studies showed an important role of these enzymes in several developmental and disease-related processes in both animals and plants through a control on polyamine homeostasis in response to normal cellular signals, drug treatment, environmental and/or cellular stressors. The production of toxic aldehydes and reactive oxygen species, H(2)O(2) in particular, by these oxidases using extracellular and intracellular polyamines as substrates, suggests a mechanism by which the oxidases can be exploited as antineoplastic drug targets. This minireview summarizes recent advances on the physiological roles of polyamine catabolism in animals and plants in an attempt to highlight differences and similarities that may contribute to determine in detail the underlined mechanisms involved. This information could be useful in evaluating the possibility of this metabolic pathway as a target for new antiproliferative therapies in animals and stress tolerance strategies in plants.     

PAF and its metabolic enzymes in healthy volunteers: interrelations and correlations with basic characteristics

PAF (1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine), a potent inflammatory mediator, is synthesized via the remodeling and the de novo route, key enzymes of which are acetyl-CoA:lyso-PAF acetyltransferase (lyso-PAF-AT) and DTT-insensitive CDP-choline:1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase (PAF-CPT), respectively. PAF-acetylhydrolase (PAF-AH) and its extracellular isoform lipoprotein-associated phospholipase-A(2) (Lp-PLA(2)) catabolize PAF. This study evaluated PAF levels together with leukocyte PAF-CPT, lyso-PAF-AT, PAF-AH and Lp-PLA(2) activities in 106 healthy volunteers. Men had lower PAF levels and higher activity of both catabolic enzymes and lyso-PAF-AT than women (P-values <0.05). Age was inversely correlated with PAF levels in men (r=-0.279, P=0.06) and lyso-PAF-AT in women (r=-0.280, P=0.05). In contrast, Lp-PLA(2) was positively correlated with age (r=0.201, P=0.04). Moreover, PAF-CPT was positively correlated with glucose (r=0.430, P=0.002) in women. In addition, Principal Component Analysis revealed three PAF metabolic patterns: (i) increased activities of PAF-CPT and PAF-AH, (ii) increased activities of PAF-CPT and lyso-PAF-AT and (iii) increased activity of Lp-PLA(2). The present study underlines the complexity of PAF's metabolism determinants.     

CT dosimetry considerations in non typical conditions: The effect of scan field of view and table height selection

PurposeTo experimentally investigate the effect of the scan field of view (SFOV) selection and table height settings on the Computed Tomography Dose Index (CTDI) and the implications concerning patient effective and skin dose.MethodsAir-kerma length product (AKLP) measurements were carried out in a helical CT scanner using a pencil type dosimeter positioned in air and inside the holes of a head and a body phantom, using all available SFOV selections and different table height settings. Furthermore, using radiotherapy verification films placed on the CT table surface, the entrance surface air kerma (ESAK) profiles were derived with different SFOV and table height selections, both with and without a phantom on top of the films.ResultsThe AKLP is strongly dependent on the SFOV selection and the table height settings. Different SFOV selections correspond to the selection of different bowtie filters that shape the X-ray beam intensity, resulting in different ESAK values at the isocenter and at the other points within the scanning plane. With the off-center positioning the calculated CTDI values within the center and the periphery of the phantom change also, as a result of the different intensity and width of the X-ray beam to which are exposed to.ConclusionsThe existing protocols for calculating effective dose are limited to only two patient anatomy-SFOV combinations and cannot account for off-center positioning. Therefore, more work will be required to estimate the effective and skin dose for non-standard SFOV-patient anatomy combinations and off-center patient positioning.     

Molecular Typing of Cyst‐Forming Nematodes Globodera pallida and G. rostochiensis,Using Real‐Time PCR and Evaluation of Five Methods for Template Preparation

Globodera pallida and G. rostochiensis are two cyst‐forming nematodes known to infest potato crops, causing severe economic losses worldwide. In this study, a real‐time TaqMan PCR assay was developed and optimized for the simultaneous detection of G. pallida and G. rostochiensis. The assay's analytical and diagnostic sensitivity and specificity were evaluated using reference isolates. Four different DNA extraction methods and one rapid crude template‐preparation procedure were compared in terms of extraction purity, efficiency for PCR applications, utility and cost. Extraction methods A and B included two commercially available kits that utilize silica columns and magnetic beads, respectively. Method C was based on DNA isolation using Chelex resin, and method D was a standard chemistry in‐house protocol. Procedure E included the direct use of crude mixture composed of disrupted cysts in Tris–EDTA buffer. The multiplex TaqMan PCR assay successfully discriminated the two nematode species from all reference cyst samples and its recorded diagnostic sensitivity (Dse) and specificity (Dsp) was 100%. On the contrary, in conventional (Co) PCR tests, the overall Dsp and Dse were lower and estimated at 94 and 87% for G. pallida, and 97 and 88% for G. rostochiensis, respectively. Spectrophotometric results showed that DNA extraction methods A, B and C yielded the purest DNA and gave the lowest mean C_t values as well as the most consistent results in Co PCR. Alternative crude preparation method E resulted in statistically similar and C_t values consistent with those obtained with methods A to C when tested by TaqMan PCR. The developed assay, using crude template‐preparation E, allows the simple, accurate and cost‐effective testing of a large number of cyst samples and can be applied in surveys and certification schemes.     

The usefulness of magnetic resonance imaging of the hand and wrist in very early rheumatoid arthritis

Introduction  

Magnetic resonance imaging (MRI) was used to study the hand and wrist in very early rheumatoid arthritis (RA), and the results were compared with early and established disease.     

Nanomechanical analysis of pigmented human melanoma cells

Based on hitherto measurements of elasticity of various cells in vitro and ex vivo, cancer cells are generally believed to be much softer than their normal counterparts. In spite of significant research efforts on the elasticity of cancer cells, only few studies were undertaken with melanoma cells. However, there are no reports concerning pigmented melanoma cells. Here, we report for the first time on the elasticity of pigmented human melanoma cells. The obtained data show that melanin significantly increases the stiffness of pigmented melanoma cells and that the effect depends on the amount of melanin inside the cells. The dramatic impact of melanin on the nanomechanical properties of cells puts into question widely accepted paradigm about all cancer cells being softer than their normal counterparts. Our findings reveal significant limitations of the nanodiagnosis approach for melanoma and contribute to better understanding of cell elasticity.     

Assessing the relative effectiveness and tolerability of treatments in small cell lung cancer: A network meta-analysis

Background: The combination of Cisplatin plus Etoposide (EP) is currently the standard treatment for small cell lung cancer (SCLC). However, a large number of alternative treatments (monotherapies and combinations) have been studied in randomized controlled trials (RCTs) to identify more effective treatments. Aim of the present study was to assess the relative effectiveness and tolerability of these treatments. Methods: PubMed, EMBASE and Cochrane Central Register of Controlled Trials were systematically searched to identify all RCTs that compared treatments for SCLC. Then, effectiveness of the treatments relative to the combination of Cisplatin plus Etoposide, reference treatment) was estimated by performing a network of treatments analysis. The analysis evaluated two efficacy outcomes (complete response – CR and objective response rate – ORR) and two tolerability outcomes (neutropenia and febrile neutropenia). All RCTs that provided data for calculating the odds ratios (OR) for the selected outcomes were considered. The network analysis involved direct and indirect analyses. Results: We identified 71 articles eligible for inclusion, involving 91 different treatments. In total, 16,026 patients were included in the analysis. In the direct analysis the combination of Cisplatin plus Cyclophosphamide plus Etoposide plus Epirubicin showed better response than EP for the ORR outcome, but with worse tolerability (presence of neutropenia). The indirect analysis revealed that the combination of Cisplatin plus Doxorubicin plus Etoposide (plus Vincrisitine) showed better response that EP for the ORR outcome. Conclusions: No therapy shows better response for the two efficacy outcomes (CR and ORR); though, Cisplatin plus Doxorubicin plus Etoposide plus Vincrisitine might be a promising therapy for SCLC. The results should be interpreted with caution because the network was dominated by indirect comparisons. Large scale head-to-head RCTs are needed to confirm the present findings.     

Comparison between Internalizing Anti-HER2 mAbs and Non-Internalizing Anti-CEA mAbs in Alpha-Radioimmunotherapy of Small Volume Peritoneal Carcinomatosis Using 2 1 2Pb

Background and Purpose

We assessed the contribution of antibody internalization in the efficacy and toxicity of intraperitoneal α-radioimmunotherapy (RIT) of small volume carcinomatosis using ²¹²Pb-labeled monoclonal antibodies (mAbs) that target HER2 (internalizing) or CEA (non-internalizing) receptors.

Materials and Methods

Athymic nude mice bearing 2–3 mm intraperitoneal tumor xenografts were intraperitoneally injected with similar activities (370, 740 and 1480 kBq; 37 MBq/mg) of ²¹²Pb-labeled 35A7 (anti-CEA), trastuzumab (anti-HER2) or PX (non-specific) mAbs, or with equivalent amounts of unlabeled mAbs, or with NaCl. Tumor volume was monitored by bioluminescence and survival was reported. Hematologic toxicity and body weight were assessed. Biodistribution of ²¹²Pb-labeled mAbs and absorbed dose-effect relationships using MIRD formalism were established.

Results

Transient hematological toxicity, as revealed by white blood cells and platelets numbering, was reported in mice treated with the highest activities of ²¹²Pb-labeled mAbs. The median survival (MS) was significantly higher in mice injected with 1.48 MBq of ²¹²Pb-35A7 (non-internalizing mAbs) (MS = 94 days) than in animals treated with the same activity of ²¹²Pb-PX mAbs or with NaCl (MS = 18 days). MS was even not reached after 130 days when follow-up was discontinued in mice treated with 1.48 MBq of ²¹²Pb-trastuzumab. The later efficacy was unexpected since final absorbed dose resulting from injection of 1.48 MBq, was higher for ²¹²Pb-35A7 (35.5 Gy) than for ²¹²Pb-trastuzumab (27.6 Gy). These results also highlight the lack of absorbed dose-effect relationship when mean absorbed dose was calculated using MIRD formalism and the requirement to perform small-scale dosimetry.

Conclusions

These data indicate that it might be an advantage of using internalizing anti-HER2 compared with non-internalizing anti-CEA ²¹²Pb-labeled mAbs in the therapy of small volume xenograft tumors. They support clinical investigations of ²¹²Pb-mAbs RIT as an adjuvant treatment after cytoreductive surgery in patients with peritoneal carcinomatosis.     

Wnt and planar cell polarity signaling in cystic renal disease

Cystic kidney diseases can cause end stage renal disease, affecting millions of individuals worldwide. They may arise early or later in life, are characterized by a spectrum of symptoms and can be caused by diverse genetic defects. The primary cilium, a microtubule-based organelle that can serve as a signaling antenna, has been demonstrated to have a significant role in ensuring correct kidney development and function. In the kidney, one of the signaling pathways that requires the cilium for normal development is Wnt signaling. In this review, the roles of primary cilia in relation to canonical and non-canonical Wnt/PCP signaling in cystic renal disease are described. The evidence of the associations between cilia, Wnt signaling and cystic renal disease is discussed and the significance of planar cell polarity-related mechanisms in cystic kidney disease is presented. Although defective Wnt signaling is not the only cause of renal disease, research is increasingly highlighting its importance, encouraging the development of Wnt-associated diagnostic and prognostic tools for cystic renal disease.