MiR-31 aggravates inflammation and apoptosis in COPD rats via activating the NF-κB signaling pathway.

OBJECTIVE: To study the effect of micro ribonucleic acid (miR)-31 on rats with chronic obstructive pulmonary disease (COPD) by activating the nuclear factor-κB (NF-κB) signaling pathway. MATERIALS AND METHODS: A total of 36 Sprague-Dawley rats were randomly divided into normal group (n=12), model group (n=12) and miR-31 mimics group (n=12). The rats were fed normally in normal group. In model group, the COPD model was first established, followed by intervention using normal saline. In miR-31 mimics group, the COPD model was also first established, followed by intervention using miR-31 mimics. The expression of NF-κB was detected via immunohistochemistry. Protein expressions of B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax) were determined through Western blotting. Serum levels of interleukin-6 (IL-6), IL-18 and tumor necrosis factor-α (TNF-α) were measured via enzyme-linked immunosorbent assay (ELISA). Moreover, the apoptosis was examined via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, and the relative expression of miR-31 was detected by means of quantitative polymerase chain reaction (qPCR). RESULTS: The immunohistochemistry results showed that the positive expression of NF-κB was significantly higher in the other two groups than that in normal group (p<0.05), while it was also remarkably higher in miR-31 mimics group than that in model group (p<0.05). The results of Western blotting revealed that the relative protein expression of Bax significantly increased, while that of Bcl-2 notably declined in the other two groups compared with those in normal group (p<0.05). Similarly, the relative protein expression of Bax was upregulated, while that of Bcl-2 was distinctly reduced in miR-31 mimics group compared with those in model group (p<0.05). It was found via ELISA that the model group and miR-31 mimics group had evidently higher levels of IL-6, IL-18 and TNF-α than those in normal group (p<0.05), while miR-31 mimics group also had prominently higher levels than those in model group (p<0.05). In addition, according to the TUNEL assay, the apoptosis rate remarkably increased in the other two groups in comparison with that in normal group (p<0.05), while it remarkably rose in miR-31 mimics group compared with that in model group (p<0.05). Finally, a significantly higher expression of miR-31 was observed in the other two groups than that in normal group via qPCR (p<0.05), and such a higher expression was also found in miR-31 mimics group than that in model group (p<0.05). CONCLUSIONS: MiR-31 aggravates inflammation and apoptosis in COPD rats by activating the NF-κB signaling pathway.

Bevacizumab plus chemotherapy for patients with advanced pulmonary adenocarcinoma harboring EGFR mutations.

PURPOSE: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) and bevacizumab plus chemotherapy were effective for EGFR-mutant patients. However, the appropriated treatment orders remained controvertible. We investigated the efficacy of treatment orders between bevacizumab plus chemotherapy and EGFR-TKIs for EGFR-mutant patients with advanced pulmonary adenocarcinoma. PATIENTS AND METHODS: This study involved 40 EGFR-mutant patients with advanced pulmonary adenocarcinoma who were treated with bevacizumab plus carboplatin and paclitaxel (Bev + CP) and EGFR-TKIs in different treatment orders or gemcitabine plus cisplatin (GP) in first-line setting. Seventeen patients were treated with Bev + CP and 10 cases with GP in first-line treatment. Thirteen patients received EGFR-TKIs after first-line Bev + CP regimen, while 13 patients were treated with first-line EGFR-TKIs. Progression-free survival (PFS), the response rate (ORR) and overall survival (OS) were evaluated. RESULTS: Median PFS of Bev + CP treatment was significantly longer in first-line than non-first-line settings (11.7 vs. 5.6 months, P = 0.003). Median OS was 37.8 months for EGFR-mutant patients with first-line Bev + CP followed by second-line EGFR-TKIs and 31.0 months for those with first-line EGFR-TKIs and non-first-line Bev + CP, respectively (P = 0.509). Median PFS was 11.7 (95% CI 10.6-12.8) months for Bev + CP group and 4.7 (95% CI 4.4-5.0) months for GP group with the hazard ratio of 0.17 (P = 0.001). ORR was 70.6 and 50.0% in the two groups, respectively (P = 0.415). However, there was no significant difference in median OS (33.7 vs 27.8 months, P = 0.293). CONCLUSIONS: First-line Bev + CP followed by EGFR-TKIs might possibly provide favorable prognosis for EGFR-mutant patients. Bev + CP regimen significantly prolonged PFS in first-line than non-first-line settings. These findings warrant further investigations.

Computational identification of specific splicing regulatory elements from RNA-seq in lung cancer.

BACKGROUND: Lung cancer is the most common cause of cancer-related death worldwide. Recently, deep transcriptional sequencing has been used as an effective genomic assay to get an insight into this disease. AIM: This study is carried out to identify specific regulatory elements (SREs) in lung cancer. MATERIALS AND METHODS: The RNA-sequencing data on lung cancer sample and normal sample were downloaded from NCBI. TopHat and Cufflinks were used to analyze differential alternative splicing in lung cancer by using RNA-sequencing data. Further, we searched specific SREs in lung cancer through finding over-represented hexamers around high expression exons. RESULTS: According to the Jensen-Shannon divergence between two samples and the p-value of t-test, we found 53 genes with differential alternative splicing in lung cancer. In the analysis of SREs, we found 763 specific SREs between lung cancer sample and normal sample. CONCLUSIONS: These results may give an insight into how alternative splicing causes differential expression in lung cancer.

Stroke syndromes and clinical management.

The knowledge of brain syndromes is essential for stroke physicians and neurologists, particularly those that can be extremely difficult and challenging to diagnose due to the great variability of symptom presentation and yet of clinical significance in terms of potential devastating effect with poor outcome. The diagnosis and understanding of stroke syndromes has improved dramatically over the years with the advent of modern imaging, while the management is similar to general care as recommended by various guidelines in addition to care of such patients on specialized units with facilities for continuous monitoring of vital signs and dedicated stroke therapy. Such critical care can be provided either in the acute stroke unit, the medical intensive care unit or the neurological intensive care unit. There may be no definitive treatment at reversing stroke syndromes, but it is important to identify the signs and symptoms for an early diagnosis to prompt quick treatment, which can prevent further devastating complications following stroke. The aim of this article is to discuss some of the important clinical stroke syndromes encountered in clinical practice and discuss their management.

Changes in kinetics of amino acid uptake at the ageing ovine blood-cerebrospinal fluid barrier.

Amino acids (AA) in brain are precisely controlled by blood-brain barriers, which undergo a host of changes in both morphology and function during ageing. The effect of these age-related changes on AA homeostasis in brain is not well described. This study investigated the kinetics of four AA (Leu, Phe, Ala and Lys) uptakes at young and old ovine choroid plexus (CP), the blood-cerebrospinal fluid (CSF) barrier (BCB), and measured AA concentrations in CSF and plasma samples. In old sheep, the weight of lateral CP increased, so did the ratio of CP/brain. The expansion of the CP is consistent with clinical observation of thicker leptomeninges in old age. AA concentrations in old CSF, plasma and their ratio were different from the young. Both V(max) and K(m) of Phe and Lys were significant higher compared to the young, indicating higher trans-stimulation in old BCB. Cross-competition and kinetic inhibition studies found the sensitivity and specificity of these transporters were impaired in old BCB. These changes may be the first signs of a compromised barrier system in ageing brain leading increased AA influx into the brain causing neurotoxicity.

Long-term results of Taiwan Pediatric Oncology Group studies 1997 and 2002 for childhood acute lymphoblastic leukemia.

The long-term outcome of 1390 children with acute lymphoblastic leukemia (ALL), treated in two successive clinical trials (Taiwan Pediatric Oncology Group (TPOG)-ALL-97 and TPOG-ALL-2002) between 1997 and 2007, is reported. The event-free survival improved significantly (P=0.0004) over this period, 69.3+/-1.9% in 1997-2001 to 77.4+/-1.7% in 2002-2007. A randomized trial in TPOG-97 testing L-asparaginase versus epidoxorubicin in combination with vincristine and prednisolone for remission induction in standard-risk (SR; low-risk) patients yielded similar outcomes. Another randomized trial, in TPOG-2002, showed that for SR patients, two reinduction courses did not improve long-term outcome over one course. Decreasing use of prophylactic cranial irradiation in the period 1997-2008 was not associated with increased rates of CNS relapse, prompting complete omission of prophylactic cranial irradiation from TPOG protocols, beginning in 2009. Decreased use of etoposide and cranial irradiation likely contributed to the low incidence of second cancers. High-risk B-lineage ALL, T-cell, CD10 negativity, t(9;22), infant, and higher leukocyte count were consistently adverse factors, whereas hyperdiploidy >50 was a consistently favorable factor. Higher leukocyte count and t(9;22) retained prognostic significance in both TPOG-97 and TPOG-2002 by multivariate analysis. Although long-term outcome in TPOG clinical trials is comparable with results being reported worldwide, the persistent strength of certain prognostic variables and the lower frequencies of favorable outcome predictors, such as ETV6-RUNX1 and hyperdiploidy >50, in Taiwanese children warrant renewed effort to cure a higher proportion of patients while preserving their quality of life.

Age-related changes in choroid plexus and blood-cerebrospinal fluid barrier function in the sheep.

Dysfunction of the choroid plexuses (CPs) and the blood-cerebrospinal fluid barrier (BCSFB) might contribute to age-related cognitive decline and neurodegenerative disease. We used the CPs from young (1-2 years), middle-aged (3-6 years) and old (7-10 years) sheep to explore effects of aging on various aspects of CP and BCSFB functions. Total protein in the cerebrospinal fluid (CSF) was significantly higher in old compared to young sheep and CSF secretion by the CP perfused in situ was significantly lower in both old and middle-aged when compared to young sheep, which correlated with reduced (22)Na(+) uptake and efflux by the CP. Steady-state extractions of a low and medium size molecular weight extracellular space marker, (14)C-mannitol and (3)H-polyethylene glycol, respectively, were significantly higher in CPs from old compared to young animals; however, there was no significant difference in steady-state extraction of a high molecular weight marker, (125)I-bovine serum albumin. This indicates increased passive BCSFB permeability for small and medium sized molecules in old sheep. CP redox activity was significantly lower in the old animals as assessed by the MTT assay, however, there was no significant difference in ATP content and energy charge of the CP with age suggesting adequate baseline energy reserve capacity. These data indicate that normal aging processes alter protein content in the CSF, CSF secretion, integrity of the BCSFB and Na(+) flux in the epithelial layer, which could impact on CSF homeostasis and turnover.

Subclinical hypothyroidism is a risk factor for nephropathy and cardiovascular diseases in Type 2 diabetic patients.

AIMS: The purpose of this study was to determine the relationship between subclinical hypothyroidism and prevalence of retinopathy and nephropathy, incident cardiovascular disease, and mortality in Type 2 diabetic patients without taking thyroid medication. METHODS: Serum thyrotropin and free thyroxine concentrations were measured in 588 Type 2 diabetic subjects in Taipei Veterans General Hospital, Taiwan. In a cross-sectional study, we examined the prevalence of retinopathy and nephropathy. In a longitudinal study, we examined the risk of cardiovascular disease events, cardiovascular mortality and total mortality in the 4-year follow-up. RESULTS: In the cross-sectional analysis, subclinical hypothyroidism was associated with a greater prevalence of diabetic nephropathy (odds ratio, 3.15 [95% CI, 1.48-6.69]) and did not show a high prevalence of diabetic retinopathy (odds ratio, 1.15 [95% CI, 0.59-2.26]) compare to euthyroid diabetics. During the 44.0 +/- 7.4 months of follow-up, 51 participants had cardiovascular events. The risk of cardiovascular events was significantly increased in Type 2 diabetics with subclinical hypothyroidism after adjustment for age, sex, A1C, other standard cardiovascular risk factors and medication (hazard ratio, 2.93; 95% CI, 1.15-7.48; P = 0.024), but it became nonsignificant after additional adjustment for urinary albumin-to-creatinine ratio (hazard ratio, 2.06; 95% CI, 0.67-6.36; P = 0.211). The rates of cardiovascular-related and total mortality did not significantly differ by thyroid status. CONCLUSIONS: Type 2 diabetic patients with subclinical hypothyroidism are associated with an increased risk of nephropathy and cardiovascular events, but not with retinopathy. Our data suggest that the higher cardiovascular events in subclinical hypothyroidism with Type 2 diabetes may be mediated with nephropathy.

Redox potential of tea infusion as an index for the degree of fermentation.

Redox potential of tea infusion is suggested as an index for the extent of tea fermentation. The potential was measured between platinum and Ag/AgCl electrode pair with a voltmeter with high input impedance (>1000 Gohms). Phosphate buffer (10 mM, pH 7.0) was used to extract the infusion and served as the supporting electrolytes for the electrochemical measurement. The reliability (the Nernst's behavior) for redox potential measurement was verified with a standard redox couple, ferricyanide/ferrocyanide. Tentative interferences from dissolved oxygen and the major coexisting reducing chemical, ascorbate, were discussed. Redox potential showed strong correlation with the fermentation process during indoor withering process. Eleven kinds of tea with different fermentation extents including Sencha, Pilochun, Pouchong, Formosa oolong tea, Lipton green tea, Lipton black tea, and Taiwanese black tea were tested.

Dose-dependent transthyretin inhibition of T4 uptake from cerebrospinal fluid in sheep.

Transthyretin (TTR), synthesized by the choroid plexuses (CP) has an important role in transporting thyroxine from blood to cerebrospinal fluid (CSF). However, the role of TTR on thyroxine transport from CSF to either blood or brain is not clear. By using the incubated isolated ovine brain tissues technique, we found the CP accumulated most 125I-T4 compared to ventricular ependymal, frontal cortex or cerebellum. The accumulation was higher in the young CP than the old. There was dose-dependent inhibition by TTR on 125I-T4 accumulation in the brain tissues, and kinetics of T4 accumulation in presence of TTR was obtained by plotting a double reciprocal of B (bound) versus TTR concentration curve. The KD of 125I-T4 binding to TTR was higher in the CP compared to other tissues, suggesting that CP competes with TTR for T4 binding to a greater extent than the other tissues. Using the isolated perfused CP preparation, TTR significantly inhibited 125I-T4 efflux across CP from the CSF to blood side. Bovine serum albumin (BSA) was also able to inhibit 125I-T4 accumulation in the incubated tissues, but required higher concentrations to reach the level of inhibition seen with TTR. In conclusion, this study found a significant role for CSF TTR in preventing T4 loss to blood across the CP, and TTR inhibited both CP and selected brain tissue uptake in a dose-dependent manner. The physiological relevance of TTR may relate to preventing T4 loss from CSF and encouraging redistribution of hormone around the brain in CSF.

Improved treatment results for childhood acute myeloid leukemia in Taiwan.

To improve treatment results for children with de novo acute myeloid leukemia (AML), we introduced a novel protocol, Taiwan Pediatric Oncology Group-AML-97A, for AML other than acute promyelocytic leukemia (APL), for which modified conventional protocols were used. From January 1, 1997, to December 31, 2002, 141 children younger than 17 years old with de novo AML were enrolled. In total, 117 patients with non-APL AML were treated with induction therapy of idarubicin and cytarabine (Ara-C), postremission therapy with high-dose Ara-C - containing regimens for four monthly courses, and moderate-dose therapy with idarubicin and Ara-C for four monthly courses. The first 19 patients with APL were treated with all-trans retinoic acid, idarubicin and Ara-C, with the remaining five patients receiving all-trans retinoic acid and idarubicin, followed by maintenance therapy for 2 years. Stem cell transplantation was performed in 29 patients in first remission with a similar outcome as chemotherapy alone. The remission rate in the AML-97A study was 90%, the 5-year survival 51 +/- 5.3% (s.e.) and the 5-year event-free survival 50 +/- 4.8%; for APL, these were 100%, 86 +/- 7.0, and 75 +/- 9.8%. For the whole group, the 5-year survival was 57 +/- 4.7% and the 5-year event-free survival 54 +/- 4.4%. The AML-97A regimen was well tolerated.

The effect of hyperbaric oxygen on human oral cancer cells.

Discoveries of the beneficial cellular and biochemical effects have strengthened the rationale for the administration of hyperbaric oxygen therapy (HBO2) as an adjunctive therapy for the treatment of osteoradionecrosis (ORN). Malignancies, however, are considered a contraindication for HBO2 because of the possible tumor-promoting effects. The aim of this study was to examine the effects of HBO2 therapy on tumor weight, and to measure the progression of apoptosis and tumor cell proliferating activity in a cultured human oral cancer cell line. Twenty 5-week-old male NODscid mice underwent daily HBO2 of 2.5 atm abs, 90 minutes for 20 treatments. The control group, n = 20, did not undergo HBO2 and tumor weight, apoptosis index, and proliferating activity parameters were compared between the two groups. The results showed no significant differences (p < 0.05) in the whole-body weights, tumor weights, apoptotic index or proliferating activity index between the two groups. By using the apoptosis and proliferating activity assays which were better indicators of tumor cell growth than tumor weight alone, our results suggest that the clinical application of HBO2 does not promote the growth or proliferation of human oral cancer cells.

Cell surface glypicans are low-affinity endostatin receptors.

Endostatin, a collagen XVIII fragment, is a potent anti-angiogenic protein. We sought to identify its endothelial cell surface receptor(s). Alkaline phosphatase- tagged endostatin bound endothelial cells revealing two binding affinities. Expression cloning identified glypican, a cell surface proteoglycan as the lower-affinity receptor. Biochemical and genetic studies indicated that glypicans' heparan sulfate glycosaminoglycans were critical for endostatin binding. Furthermore, endostatin selected a specific octasulfated hexasaccharide from a sequence in heparin. We have also demonstrated a role for endostatin in renal tubular cell branching morphogenesis and show that glypicans serve as low-affinity receptors for endostatin in these cells, as in endothelial cells. Finally, antisense experiments suggest the critical importance of glypicans in mediating endostatin activities.

Assays for angiotensin converting enzyme inhibitory activity.

A colorimetric method and a capillary electrophoresis procedure were developed for quantifying histidyl-leucine and hippurate, respectively. The colorimetric method is sensitive (extinction coefficient = 7.5 mM(-1) cm(-1)) and reproducible (CV = 1.7%, n = 5), which is based on a selective chromogenic reaction for histidyl-leucine (lambda(max) = 390 nm) using o-phthalaldehyde. For samples containing unusually high levels of histidine and/or histidyl peptides, the separation-based approach is preferable. The capillary electrophoresis method makes use of an in-capillary microextraction technique; complicated samples can be measured in less than 4 min without pretreatment. Protocols using both methods to measure angiotensin converting enzyme inhibitory activity were proposed.

Characterization of an important enzymatic component in collagenase that is essential for the effective digestion of the human and porcine pancreas.

Recent clinical results from Edmonton have demonstrated the feasibility of achieving normoglycemia in type I diabetic patients by islet transplantation. One of the key issues in obtaining this success was transplanting sufficient numbers of islets by sequential transplants. Although the development of semipurified endotoxin-free Clostridium histolyticum-derived collagenase (Liberase) has improved islet yields from the human pancreas, batch-to-batch variation and loss of activity with time still hampers progress in obtaining consistent islet preparations. In order to define key components of crude collagenase, a panel of monoclonal antibodies (McAbs) was raised against crude collagenase. Monoclonal antibodies were generated by fusions between splenocytes of BALB/c mice immunized with Boheringer P collagenase and the myeloma cell line NS-0. These monoclonal antibodies were used as probes to study molecular differences between effective and ineffective collagenase batches using Western blotting. Two monoclonal antibodies (LDS71 and LDS81) were raised and characterized as recognizing separate epitopes on a 125-kDa component. Western blotting indicated that the 125-kDa band was rapidly broken down by storage or by dialysis in the presence of dithiothreitol. However, this breakdown could be prevented by the addition of leupeptin (a protease inhibitor) to the dialysis buffer. On testing fractions at 5-min intervals from the "Ricordi" digestion circuit during porcine and human pancreas digestion, the 125-kDa component was rapidly broken down in relatively ineffective collagenase batches but in effective batches was present throughout the digestion process. The correlation between the presence of the 125-kDa band and effectiveness of pancreas digestion suggests that this may be a key component in the formulation of C. histolyticum collagenase.

Mechanisms underlying preferential assembly of heparan sulfate on glypican-1.

Glypicans are major cell surface heparan sulfate proteoglycans, the structures of which are characterized by the presence of a cysteine-rich globular domain, a short glycosaminoglycan (GAG) attachment region, and a glycosylphosphatidylinositol membrane anchor. Despite strong evolutionary conservation of the globular domains of glypicans, no function has yet been attributed to them. By using a novel quantitative approach for assessing proteoglycan glycosylation, we show here that removal of the globular domain from rat glypican-1 converts the proteoglycan from one that bears approximately 90% heparan sulfate (HS) to one that bears approximately 90% chondroitin sulfate. Mutational analysis shows that sequences at least 70 amino acids away from the glypican-1 GAG attachment site are required for preferential HS assembly, although more nearby sequences also play a role. The effects of the glypican-1 globular domain on HS assembly could also be demonstrated by fusing this domain to sequences representing the GAG attachment sites of other proteoglycans or, surprisingly, simply by expressing the isolated globular domain in cells and analyzing effects either on an exogenously expressed glypican-1 GAG attachment domain or on endogenous proteoglycans. Quantitative analysis of the effect of the globular domain on GAG addition to proteoglycan core proteins suggested that preferential HS assembly is achieved, at least in part, through the inhibition of chondroitin sulfate assembly. These data identify the glypican-1 globular domain as a structural motif that potently influences GAG class determination and suggest that an important role of glypican globular domains is to ensure a high level of HS substitution of these proteoglycans.

Treatment results of the TPOG-NHL92 protocols for childhood non-Hodgkin's lymphomas in Taiwan: a report from the Taiwan Pediatric Oncology Group (TPOG)

A nation-wide chemotherapeutic trial for childhood non-Hodgkin's lymphoma (NHL) was conducted by the Taiwan Pediatric Oncology Group (TPOG). Four TPOG-NHL92 protocols based on stage and histology were activated in 1992: TPOG-92LD (treatment duration: 8 months) was used for localized (stages I/II) NHL with any histology, 92LB (2 years), 92SNC (5 months), and 92LC (1 year) for advanced (stages III/IV) lymphoblastic (LB), small non-cleaved cell (SNC), and large cell (LC) lymphoma, respectively. From January 1992 through June 1998, 200 children with newly diagnosed NHL from 13 member hospitals of TPOG were enrolled. There were 140 boys and 60 girls. Their ages at diagnosis ranged from 2.4 months to 18.3 years with a median of 8.2 years. There were 54 (27.3%) patients with LB, 94 (47.5%) with SNC including B-cell acute lymphoblastic leukemia (B-ALL), and 50 (25.2%) with LC. Stages I, II, III, and IV (including B-ALL) of the disease comprised 5%, 10%, 43%, and 42% of cases, respectively. There were 176 patients eligible for evaluation of treatment results. The remission rate of induction was 82.4%, induction failed in 22 (12.5%) patients, and nine patients died during induction. As of August 31, 1999, 26 patients relapsed, six died during remission, one patient developed secondary acute myelomonocytic leukemia, and 105 patients remained in continuous remission with a median remission duration of 49 months. The event-free survival (EFS) at 7 years was 63.5%, 61.5% and 65% for LB, SNC, and LC groups (P = 0.8298). The 7-year EFS for stages I/II, III, and IV of the disease was 73%, 68.9%, and 50.3% (P = 0.0212), respectively. We concluded that following the strategy of stratification of therapy, only disease stages had prognostic significance in this study. More efforts are needed to improve our treatment results.

Neutrophils are cytotoxic and growth-inhibiting for neuroblastoma cells with an anti-GD2 antibody but, without cytotoxicity, can be growth-stimulating.

Neutrophils and mononuclear cells (MNC) can mediate antibody-dependent cellular cytotoxicity (ADCC) against cancer cells. To study cytotoxicity and growth inhibition of neuroblastoma cells by neutrophils and MNC with chimeric anti-disialoganglioside (GD2) monoclonal antibody (mAb) ch14.18, we developed digital image microscopy scanning (DIMSCAN) assays that measure fluorescence of target cells in 96-well plates after 6-18 h (cytotoxicity assay) or 7 days (growth assay). Neuroblastoma cell lines (GD2-positive: SMS-KCN, SMS-LHN, LA-N-1; GD2-negative: SK-N-SH) were preloaded with calcein acetoxymethyl ester for the cytotoxicity assay or labeled in situ after 7 days of culture with fluorescein diacetate in the growth assay. Fluorescence, as quantified by DIMSCAN, was correlated with neuroblastoma cell number in both assays (100-2000 cells/well). In the cytotoxicity test, both neutrophils and MNC effectively mediated ADCC of GD2-positive but not GD2-negative neuroblastoma cell lines. Cytotoxicity of both neutrophils and MNC increased with effector to target cell (E:T) ratio (5-50:1) and mAb ch.14.18 dose (0.1-10 microg/ml). ADCC of neutrophils, but not MNC, increased with addition of GM-CSF. Neutrophils, especially with rhGM-CSF, significantly suppressed growth of GD2-positive cell lines at a high E:T ratio (50:1) and mAb dose (10 microg/ml). Without antibody, neutrophils inhibited growth of one cell line (LA-N-1) but stimulated growth of two others (SMS-KCN, SMS-LHN). If neuroblastoma cells did not express GD2 (SK-N-SH), neutrophils stimulated growth whether or not antibody was present. Neutrophil culture supernatants increased growth of SK-N-SH, LA-N-1, and SMS-KCN cells, and MNC culture supernatants increased growth of SK-N-SH. In conclusion, neutrophils can mediate cytotoxicity and growth inhibition with a chimeric anti-GD2 antibody but also can promote tumor cell growth if antibody is not present or if GD2 is not expressed.