Could nitrite/free nitrous acid favour GAOs over PAOs in enhanced biological phosphorus removal systems?

Enhanced biological phosphorus removal (EBPR) normally occurs together with nitrogen removal in wastewater treatment plants (WWTPs). In recent years, efforts have been devoted to remove nitrogen via the nitrite pathway (oxidation of ammonia to nitrite and reduction of nitrite to nitrogen gas without going through nitrate), reducing the requirement for carbon and oxygen in the plant. However nitrite and free nitrous acid (FNA), the protonated species of nitrite, have been shown to cause EBPR deterioration under certain concentrations. This study provides a direct comparison between the different levels of FNA inhibition in the aerobic processes of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) by reviewing the studies published in this area. Also, new data is presented assessing the FNA effect on the anaerobic metabolism of these two groups of bacteria. Overall, FNA has shown inhibitory effects on most of the processes involved in the metabolism of PAOs and GAOs. However, the inhibition-initiation levels are different between different processes and, even more importantly between the two groups. In general, PAOs appear to be more affected than GAOs at the same level of FNA, thus giving GAOs competitive advantage over PAOs in EBPR systems when nitrite is present.

Abstract P5-05-11: The Cellular Impact of HuR (Human (Hu) Antigen R) in Breast Cancer Cells on the Growth and Invasion In Vitro and the Expression of Cyclin D1 and MMP-9

Introduction: HuR, a ubiquitously expressed member of the Hu family, selectively binds and stabilizes ARE-containing mRNAs encoding proto-oncogenes, cell cycle regulators, cytokines and growth factors. The role of HuR and its cellular function in breast cancer remains unclear. In the present study, we aimed to provide new insights into the molecular and cellular implication of HuR in breast cancer.

Materials and methods. We first constructed a set of anti-HuR ribozyme transgenes that targeted human HuR. Breast cancer cells were transfected with the transgene, in order to establish new sublines with HuR expression knocked down. Cell growth and invasiveness were investigated using in vitro cell models. The expression of cyclin-D1 and MMP2 were determined using immunocytochemistry, Western blotting and polymerase chain reaction.

Results: Here, we show that MCF7 and MDA-MB-231 cells breast cancer cells stability transfected with a hammerhead ribozyme transgene specifically targeted to HuR (MCF7HuRKO and MDA-MB-231HuRKO) have a reduction in HuR expression both at mRNA and protein levels. Using these new sublines of breast cancer cells, the in vitro growth was evaluated. We showed that that HuR knockdown dramatically reduced cell growth in MCF7 cells (P < 0.001) and to a lesser degree reduced that in MDA MB 231 cells. We further demonstrated that reduction of HuR in MDA MB 231 cells (MDA-MB-231HuRKO) resulted in a significant reduction of the in vitro invasiveness in MDA-MB-231 cells (P < 0.001), although the same failed to occur to MCF-7 cells. Furthermore, we found that the decreased cell growth rate in MCF7 cells following HuR knockdown was seen together with a reduction in cyclin D1 transcript and protein levels. It was also interest to observe that the change in invasiveness in MDA-MB-231 cells after HuR knockdown was accompanied by a decrease in MMP-9 levels.

Conclusion: Our study shows that targeting HuR can influences breast cancer cell growth and invasion and suggests a role for HuR in vitro in enhancing breast cancer cell growth and invasion. These changes may be facilitated through changes in the level of cyclin D1 and MMP-9.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-05-11.

Phase I and pharmacological study of the broad-spectrum tyrosine kinase inhibitor JNJ-26483327 in patients with advanced solid tumours

Background:

JNJ-26483327 is an oral, potent, multi-targeted tyrosine kinase inhibitor, inhibiting kinases of epidermal growth factor receptor (EGFR)-1, -2 and -4, rearranged during transfection (RET) receptor, vascular endothelial growth factor receptor (VEGFR)-3 and Src family (Lyn, Fyn, Yes) at low nanomolar concentrations. This phase I, accelerated titration study assessed maximum tolerated dose, safety, pharmacokinetics and pharmacodynamic effects of JNJ-26483327.

Methods:

Nineteen patients with advanced cancers received JNJ-26483327 continuous twice daily (BID) in escalating dose cohorts ranging from 100 to 2100 mg. Pharmacodynamic effects were assessed in paired skin biopsies and blood.

Results:

JNJ-26483327 was well tolerated in doses up to 1500 mg BID, with target-inhibition-related toxicity such as diarrhoea and skin rash, and other common reported toxicities being nausea, vomiting, anorexia and fatigue. At 2100 mg, two episodes of dose-limiting toxicity were observed, consisting of grade 3 anorexia and a combination of grade 3 anorexia and fatigue, respectively. Pharmacokinetics were dose proportional up to 1500 mg in which plasma levels were obtained showing anti-tumour activity in xenograft mouse models. Pharmacodynamic analysis did not show a substantial effect on expression of Ki-67, p27^kip1, phosphorylated mitogen-activated protein kinase, phosphorylated Akt and EGFR, and serum levels of sVEGFR-2, VEGF-C and VEGF-D remained unchanged. Stable disease was noted in six patients (32%).

Conclusion:

JNJ-26483327 is well tolerated and shows a predictable pharmacokinetic profile; the recommended dose for further studies is 1500 mg BID.

The regulation of muscle glycogen: the granule and its proteins

Despite decades of studying muscle glycogen in many metabolic situations, surprisingly little is known regarding its regulation. Glycogen is a dynamic and vital metabolic fuel that has very limited energetic capacity. Thus its regulation is highly complex and multifaceted. The stores in muscle are not homogeneous and there appear to be various metabolic pools. Each granule is capable of independent regulation and fundamental aspects of the regulation appear to be associated with a complex set of proteins (some are enzymes and others serve scaffolding roles) that associate both with the granule and with each other in a dynamic fashion. The regulation includes altered phosphorylation status and often translocation as well. The understanding of the roles and the regulation of glycogenin, protein phosphatase 1, glycogen targeting proteins, laforin and malin are in their infancy. These various processes appear to be the mechanisms that give the glycogen granule precise, yet dynamic regulation.

Gemcitabine combined with gum mastic causes potent growth inhibition and apoptosis of pancreatic cancer cells

AIM

To investigate the antiproliferative and apoptotic effects of gemcitabine combined with gum mastic and the underlying mechanisms in human pancreatic cancer cell lines.

METHODS

Cell proliferation and apoptosis were examined using the methyl thiazolyl tetrazolium (MTT) assay and propidium iodine staining, respectively. The expression of Bcl-2, Bax, NF-kappaB p65 subunit, and IkappaBalpha protein was measured using Western blotting.

RESULTS

Gemcitabine 0.01-100 microg/mL inhibited cell proliferation and induced apoptosis in both pancreatic cancer BxPC-3 and COLO 357 cells. Gum mastic 40 microg/mL significantly potentiated the antiproliferative and apoptotic effects of gemcitabine 10 microg/mL after 72-h treatment. When cells were treated with gemcitabine in combination with gum mastic, the IkappaBalpha level was increased, whereas NF-kappaB activation was blocked; the expression of Bax protein was substantially increased, but Bcl-2 protein was down-regulated.

CONCLUSION

Gemcitabine combined with gum mastic causes potent apoptosis in pancreatic cancer cells. The combination may be an effective therapeutic strategy for pancreatic cancer.

Efficient inhibition of B-cell lymphoma xenografts with a novel recombinant fusion protein: anti-CD20Fab-LDM

Lidamycin (LDM) is a new member of enediyne antitumor antibiotics family that can be separated and reconstituted. It consists of a labile active enediyne chromophore (AE) and a noncovalently bound apoprotein (LDP). LDM is now in phase II clinical trials. In this study, we described the antitumor features of a fusion protein of LDM, anti-CD20Fab-LDM, targeted to CD20 expressed by B-lymphoid malignancies. Especially, LDM was prepared by a novel two-step method including DNA recombination and molecular reconstitution. Anti-CD20Fab-LDM exerted potent cytotoxicity against CD20+ B-cell lymphoma cell lines in vitro (IC50: 10-30 pM) and in the Raji xenograft model. Two Raji xenografts were allowed to grow to an initial mass of 80 and 500 mm³, respectively, and then anti-CD20Fab-LDM was administered intravenously with the highest dose of 4 nmol kg⁻¹ . The inhibition rates of tumor growth were 90.1 and 85%, which were saliently superior to those of nontargeted LDM. It is noteworthy that anti-CD20Fab-LDM can inhibit the growth of patient-derived cells, including rituximab-resistant patient-derived cells. Thus, CD20-targeted delivery of LDM is a specific and potent therapeutic strategy for B-lymphoid malignancies. In addition, the two-step approach could serve as a new technology platform for making a series of highly potent engineered antibody-based drugs.

Expression and prognostic significance of focal adhesion kinase in hepatocellular carcinoma

AIM

To examine the expressions of focal adhesion kinase (FAK) and its clinical significance in hepatocellular carcinoma (HCC).

METHODS

We determined the expression levels of FAK on both steady-state mRNA and protein levels in 50 HCC samples by quantitative real-time PCR and immunohistochemistry, respectively. The correlations between FAK expression and various clinicopathological parameters were analyzed.

RESULTS

The expression of FAK on the mRNA level was consistent with that on the protein level. FAK mRNA levels in tumor tissues were significantly higher than in the paratumor tissues (0.229 +/- 0.027 vs. 0.163 +/- 0.019; P < 0.001), but lower than in the macroscopic cancer emboli (0.506 +/- 0.155 vs. 0.377 +/- 0.176; P < 0.05). Compared within the tumor tissues, FAK expressions were significantly higher in those with cancer emboli than those without (0.343 +/- 0.05 vs. 0.165 +/- 0.025; P = 0.003). Univariate and multivariate analyses revealed that FAK expression was an independent prognostic factor for disease-free survival and overall survival. Both 3-year disease-free survival rates and overall survival rates in FAK-negative group were significantly higher than in positive group (52 vs. 20% and 72 vs. 29%, P < 0.001).

CONCLUSION

Our results suggest that FAK expression is up-regulated in HCC and its expression is an independent prognostic factor for HCC.

Modelling and simulation revealing mechanisms likely responsible for achieving the nitrite pathway through aeration control

Nitrogen removal via nitrite has recently gained a lot of interest because it results in significant savings in both aeration costs and COD (chemical oxygen demand) requirements for denitrification, when compared to the conventional biological nitrogen removal via nitrate. The effectiveness of two different control strategies to achieve the nitrite pathway in systems with sludge retention has been experimentally demonstrated: (i) control of aerobic phase length, with which aeration is terminated as soon as ammonia is completely oxidised; (ii) operation at low DO setpoints in the aerobic phase. These strategies have been extensively studied in nitrifying reactors and are currently applied in real systems achieving biological carbon, nitrogen and phosphorus removal. In this work, we aim to demonstrate, through modelling and simulation, that the competition between nitrite reducers and nitrite oxidisers for nitrite, rather than kinetic selection plays a major role in NOB washout. Moreover, the results show that the occurrence of simultaneous nitrification and denitrification under "aerobic" conditions is very helpful for the nitrite pathway obtainment and for a more efficient COD utilisation.

Repeated Intrathecal Administration of Ropivacaine Causes Neurotoxicity in Rats

Previous studies suggest that ropivacaine causes the least neurotoxicity among local anaesthetics. Most data derive from a single injection of ropivacaine into the subarachnoid space. The histological changes and behavioural effects of repeated intrathecal administration have yet to be studied. We examined the possible neurotoxicity of multiple doses of intrathecal ropivacaine in rats.

Rats received 0.12 ml/kg body weight ropivacaine in normal saline at concentrations of 0.25%, 0.5%, 0.75% and 1.0% at 90-minute intervals via an implanted intrathecal catheter (ID 0.12 mm, OD 0.35 mm) for 48 hours. At L3, the spinal cord and posterior roots were examined by light and electron microscopy. We performed in situ TUNEL assay to evaluate apoptosis in the spinal cord. Sensory threshold to noxious stimulation along with behavioural change were also studied.

Both 0.75% and 1.0% ropivacaine induced neuronal injury characterised by infiltration of inflammatory cells, vacuolation of myelin sheaths and axons, abnormal morphology of neurons and apoptosis in the spinal cord, mainly in posterior roots and the adjacent posterior white matter. Compared to controls, the percentage of maximum possible effect did not show any significant differences between the rats treated with variable concentrations of ropivacaine or tested with either heat or mechanical stimulation. As expected, the recovery time to normal ambulation was prolonged as the ropivacaine concentration was increased.

Ropivacaine can induce neurotoxicity and trigger apoptosis in a dose-dependent manner after repeated intrathecal administration. Although the clinical safety profile of ropivacaine appears favourable compared with other local anaesthetics, it is possible our findings have clinical significance.

Immobilization of Alcaligenes faecalis penicillin G acylase on epoxy-type supports

Alcaligenes faecalis penicillin G acylase has several desired features over other penicillin G acylases and its use in industry requires immobilization. In this work, two novel supports ZH-EP (epoxy-type) and ZH-HA (epoxy-amino type) were used to immobilize Alcaligenes faecalis penicillin G acylase (AfPGA) with Eupergit C as reference. The saturation of immobilized protein on ZH-EP (269 mg/g, 116 h) and ZH-HA (296 mg/g, 15 h) was obtained more rapidly than Eupergit C (197 mg/g, 260 h). And the activity of immobilized AfPGA on ZH-EP (520 U/g) and ZH-HA (2200 U/g) was higher than that on Eupergit C (310 U/g). The properties of three immobilized enzymes were compared and no obvious difference was observed, which indicated that ZH-EP and ZH-HA were promised in industry.