Function characterization of a glyco-engineered anti-EGFR monoclonal antibody cetuximab in vitro.

AIM: To evaluate the biochemical features and activities of a glyco-engineered form of the anti-human epidermal growth factor receptor monoclonal antibody (EGFR mAb) cetuximab in vitro. METHODS: The genes encoding the Chinese hamster bisecting glycosylation enzyme (GnTIII) and anti-human EGFR mAb were cloned and coexpressed in CHO DG44 cells. The bisecting-glycosylated recombinant EGFR mAb (bisec-EGFR mAb) produced by these cells was characterized with regard to its glycan profile, antiproliferative activity, Fc receptor binding affinity and cell lysis capability. The content of galactose-α-1,3-galactose (α-Gal) in the bisec-EGFR mAb was measured using HPAEC-PAD. RESULTS: The bisec-EGFR mAb had a higher content of bisecting N-acetylglucosamine residues. Compared to the wild type EGFR mAb, the bisec-EGFR mAb exhibited 3-fold higher cell lysis capability in the antibody-dependent cellular cytotoxicity assay, and 1.36-fold higher antiproliferative activity against the human epidermoid carcinoma line A431. Furthermore, the bisec-EGFR mAb had a higher binding affinity for human FcγRIa and FcγRIIIa-158F than the wild type EGFR mAb. Moreover, α-Gal, which was responsible for cetuximab-induced hypersensitivity reactions, was not detected in the bisec-EGFR mAb. CONCLUSION: The glyco-engineered EGFR mAb with more bisecting modifications and lower α-Gal content than the approved therapeutic antibody Erbitux shows improved functionality in vitro, and requires in vivo validations.

Retrograde vs Conventional Dissection Technique in Pancreaticoduodenectomy: A Pilot Study.

IMPORTANCE: A retrograde dissection technique of pancreaticoduodenectomy in a caudocranial direction has been described recently. OBSERVATIONS: Fifteen consecutive patients who underwent retrograde pancreaticoduodenectomy were compared with 15 consecutive patients operated on through a conventional approach. The mean (SD) intraoperative blood loss was 407 (202) mL in the retrograde group compared with 423 (253) mL in the conventional group (P = .84). The mean (SD) operative duration was 255 (57) minutes in the retrograde group compared with 264 (54) minutes in the conventional group (P = .66). The overall morbidity was 7 of 15 patients (47%) in the retrograde group and 6 of 15 (40%) in the conventional group (P > .99). Neither group had a positive resection margin or a perioperative death. CONCLUSIONS AND RELEVANCE: The retrograde dissection technique had no significant difference in perioperative outcomes compared with the conventional dissection technique and could serve as an alternative dissection approach in pancreaticoduodenectomy.

Therapeutic effects of p75 tumor necrosis factor receptor monoclonal antibody on a rat model of traumatic arthritis.

BACKGROUND: The aim of the present study was to investigate the therapeutic effects of p75 tumor necrosis factor receptor monoclonal antibody D8F2 on a traumatic arthritis model in rats, and to explore the underlying mechanism. METHODS: Forty male Sprague Dawley rats were randomly divided into five groups: (A) sham operation control group, (B) traumatic arthritis model group, (C) low-dose D8F2 group (1 mg/kg), (D) medium-dose D8F2 group (3 mg/kg), and (E) high-dose D8F2 group (10 mg/kg). Joint fluid samples were collected at 72 h after surgery, and enzyme-linked immunosorbent assay was performed to measure the following inflammatory factors: tumor necrosis factor α (TNF-α) and interleukin 1ß. One week after the surgery, rats were killed, and immunohistochemical staining was applied to detect the matrix metalloproteinase (MMP1 and MMP3) expression in the synovium. In cultured synovial fibroblast experiments, the D8F2-induced ubiquitination of TNF receptor-associated factor 2 (TRAF2) was examined by immunoprecipitation, and nuclear translocation of p65 nuclear factor-κB (p65NF-κB) mediated by TNF-α and D8F2 was analyzed by western blotting. RESULTS: In the traumatic arthritis model group, the inflammatory factors and MMPs were significantly increased relative to the sham operation control group (P < 0.05), whereas D8F2 could downregulate these factors in a dose-dependent manner (P < 0.05). The results from in vitro studies indicated that D8F2 can induce TRAF2 ubiquitination and inhibit the nuclear translocation of p65NF-κB mediated by TNF-α. CONCLUSIONS: p75 Tumor necrosis factor receptor monoclonal antibody has a therapeutic effect on traumatic arthritis, which may occur via the downregulation of inflammatory factors and MMPs at the transcription level because of TRAF2 degradation and inhibited activation of NF-κB.

A study on inhibition of inflammation via p75TNFR signaling pathway activation in mice with traumatic brain injury.

OBJECTIVE: To investigate the effects of and mechanisms underlying the activation of the p75 tumor necrosis factor receptor (p75TNFR) signaling pathway in inflammatory responses in mice with traumatic brain injury. METHODS: We first generated hybridomas that produced antibodies specific for p75TNFR, by inoculating BALB/c mice with antigenic peptides derived from mouse p75TNFR, which is critical to the binding of tumor necrosis factor-alpha (TNF-α) and p75TNFR. The isotype, epitope, titer, specificity, and affinity constant of monoclonal antibodies (mAbs) were determined using commercial kits and enzyme-linked immunosorbent assay. We then screened the agonist antibody via L929 cytotoxicity assay. The levels of inflammatory factors were detected in C57BL/6 mice with traumatic brain injury and then the mice were injected with either saline (control) or p75TNFR agonist mAb. Furthermore, we investigated the effects of p75TNFR agonist mAb on p38MAPK and nuclear factor-κB signals. RESULTS: Seven mAbs against p75TNFR were generated. Among them, the mAb D8F2 could markedly enhance the cytotoxicity of TNF-α on L929 cells. In a traumatic brain injury model, D8F2 could inhibit the levels of inflammatory factors and downregulate RNA transcription of these factors by suppressing the activation of p38 mitogen-activated protein kinase and nuclear factor-κB. CONCLUSION: The mAb D8F2 could inhibit posttraumatic inflammatory responses effectively. In this study, we developed an agonist anti-mouse p75TNFR mAb, which may be used in the future to devise new strategies for the clinical treatment of inflammation after trauma.

EGFR-mediated G1/S transition contributes to the multidrug resistance in breast cancer cells.

Despite the improvement of strategies against cancer therapy, the multidrug resistance (MDR)is the critical problem for successful cancer therapy. Recurrent cancers after initial treatment with chemotherapy are generally refractory to second treatments with these anticancer therapies. Therefore, it is necessary to elucidate the therapy-resistant mechanism for development of effective therapeutic modalities against tumors. Here we demonstrate a phase-specific chemotherapy resistance due to epidermal growth factor receptor (EGFR) in human breast cancer cells. Thymidine-induced G1-arrested cultures showed upregulated chemosensitivity, whereas S-phase arrested cells were more resistant to chemotherapeutic agents. Overexpression of EGFR promoted the MDR phenotypes in breast cancer cells via accelerating the G1/S phase transition, whereas depletion of EGFR exerted the opposite effects. Furthermore, CyclinD1, a protein related to cell cycle, was demonstrated to be involved in above EGFR-mediated effects since EGFR increased the expression of CyclinD1, and the specific RNA interference against CyclinD1 could primarily abolish the EGFR-induced MDR phenotypes. These data provide new insights into the mode by which MDR breast cancers evade cytoxic attacks from chemotherapeutic agents and also suggest a role for EGFR-CyclinD1 axis in this process.

Identification and assessment of new biomarkers for colorectal cancer with serum N-glycan profiling.

BACKGROUND: The objectives of this study were to identify and validate the diagnostic value of N-glycan markers in colorectal cancer (CRC) and to uncover their underlying molecular mechanism. METHODS: In total, 347 individuals, including patients with CRC, patients with colorectal adenoma, and healthy controls, were divided randomly into a training group (n = 287) and retrospective validation groups (n = 60). Serum N-glycan profiling was analyzed by DNA sequencer-assisted/flurophore-assisted carbohydrate electrophoresis (DSA-FACE). Two diagnostic models were constructed based on N-glycan profiling with logistic stepwise regression. The diagnostic performance of each model was assessed further in retrospective, prospective (n = 43), and follow-up (n = 46) cohorts. Lectin blot and reverse transcriptase-polymerase chain reaction were used to analyze the total core-fucosylated residues and molecular expression involved in core-fucosylation modifications in CRC. RESULTS: Two diagnostic models designated CRCglycoA and CRCglycoB were constructed to differentiate CRC from normal and adenoma, respectively. The areas under the receiver operating characteristic curves (AUC) of both CRCglycoA and CRCglycoB were higher than the AUC of carcinoembryonic antigen (CEA) (CRCglycoA, 0.92 vs 0.81; CRCglycoB, 0.81 vs 0.73). The sensitivity and accuracy of CRCglycoA improved from 21.7% to 25% and from 11.63% to 18% in the training cohort, the retrospective cohort, and the prospective cohorts compared with the sensitivity and accuracy of CEA. The sensitivity of CRCglycoB improved from 20% to 28.23%. Both altered N-glycans, and results from the diagnostic models were reversed after curative surgery. The level of total core fucose residues and fucosyltransferase were decreased significantly in CRC. CONCLUSIONS: The current results indicated that the N-glycan markers based diagnostic models are new, valuable, noninvasive alternatives for identifying CRC. The authors concluded that decreased fucosyltransferase may be responsible for decreased levels of total core-fucosylated modification in both tissues and serum from patients with CRC.

Cellular prion protein promotes glucose uptake through the Fyn-HIF-2α-Glut1 pathway to support colorectal cancer cell survival.

Cellular prion protein (PrPc) is a glycosylphosphatidylinositol-anchored membrane protein that has various physical functions, including protection against apoptotic and oxidative stress, cellular uptake of copper ions, transmembrane signaling, and adhesion to the extracellular matrix. In this study, we show that PrPc is highly expressed in colorectal adenocarcinomas. Transcriptome profiling of PrPc-depleted DLD-1 cells revealed downregulation of glucose transporter 1 (Glut1). PrPc is shown to be involved in regulating Glut1 expression through the Fyn-HIF-2α pathway. As Glut1 is the natural transporter of glucose and is required for the high glycolytic rate seen in colorectal tumors, silencing of PrPc reduced the proliferation and survival rate of colorectal cancer cells in vitro. In vivo, knockdown of PrPc by hydrodynamic injection with a cocktail of PrPc-shRNA-encoding plasmids also inhibited tumorigenicity in a xenograft model in nude mice. In summary, our data characterize a novel molecular mechanism that links PrPc expression to the regulation of glycolysis. Targeting PrPc will therefore be a promising strategy to overcome the growth and survival advantage in colorectal tumors.

The effects of hydrogen-rich saline on the contractile and structural changes of intestine induced by ischemia-reperfusion in rats.

BACKGROUND: Hydrogen has been considered as a novel antioxidant that prevents injuries resulted from ischemia-reperfusion (I/R) injury in various tissues. The study was designed to determine the effect of hydrogen-rich saline on the smooth muscle contractile response to KCl, and on epithelial proliferation and apoptosis of intestine subjected to I/R. METHODS: Intestinal I/R injury was induced in Sprague-Dawley rats using bulldog clamps in superior mesenteric artery by 45 min ischemia followed by 1 h reperfusion. Rats were divided randomly into four groups: sham-operated, I/R, I/R plus saline treatment, and I/R plus hydrogen-rich saline treatment groups. Hydrogen-rich saline (>0.6 mM, 6 mL/kg) or saline (6 mL/kg) was administered, respectively, via tail vein 30 min prior to reperfusion. Following reperfusion, segments of terminal jejunum were rapidly taken and transferred into isolated organ bath and responses to KCl were recorded. Samples of terminal jejunum were also taken for measuring malondialdehyde and myeloperoxidase. Apoptosis in intestinal epithelium was determined with terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling technique (TUNEL). Expression and distribution of proliferating cell nuclear antigen (PCNA) were detected with immunohistochemistry. RESULTS: Hydrogen-rich saline treatment significantly attenuated the severity of intestinal I/R injury, with inhibiting of I/R-induced apoptosis, and promoting enterocytes proliferation. Moreover, Hydrogen-rich saline treatment significantly limited the neutrophil infiltration, lipid oxidation, and ameliorated the decreased contractility response to KCl in the intestine subjected to I/R. CONCLUSIONS: These results suggest that hydrogen treatment has a protective effect against intestinal contractile dysfunction and damage induced by intestinal I/R. This protective effect is possibly due to its ability to inhibit I/R-induced oxidative stress, apoptosis, and to promote epithelial cell proliferation.

Increased expression of annexin A1 is correlated with K-ras mutation in colorectal cancer.

The activation of K-ras gene and expression of annexin A1 play an important role in colorectal tumorigenesis. We initiated this study to analyze the possible relationship between the annexin A1 expression and the K-ras mutation status in colorectal cancer. K-ras mutations are present in one fourth to one half of colorectal cancers. Annexin A1, a 37-kDa calcium- and phospholipid-binding protein, is over-expressed in colorectal cancers and may be involved in invasive tumor growth and metastasis. Here, we examined twenty paired specimens of colorectal cancer and adjacent normal tissues for K-ras mutations and annexin A1 expression. Sequencing analysis of codons 12 and 13 of K-ras revealed the presence of K-ras mutations in six colorectal cancer tissue specimens (30%). RT-PCR and immunoblotting studies further found that the expression levels of annexin A1 mRNA and protein were increased (2.9-fold and 1.7-fold, respectively) in colorectal cancers harboring K-ras codon 12 or codon 13 mutation compared with adjacent normal tissues (P < 0.05). In colorectal cancer tissues with wild-type K-ras, 12 (85.7%) specimens showed reduced expression of annexin A1 (0.48-fold and 0.81-fold, respectively). No significant association was found between K-ras mutations or annexin A1 over-expression and demographic or other clinicopathological parameters such as gender, differentiation or metastasis. However, a significant and positive correlation was identified between K-ras mutations and annexin A1 over-expression. Our findings indicate that annexin A1 could be implicated in colorectal cancer development and progression and could be of potential use as a predictive marker for guiding targeted therapy for colorectal cancer.

Hydrogen-rich saline ameliorates the severity of l-arginine-induced acute pancreatitis in rats.

Molecular hydrogen, which reacts with the hydroxyl radical, has been considered as a novel antioxidant. Here, we evaluated the protective effects of hydrogen-rich saline on the l-arginine (l-Arg)-induced acute pancreatitis (AP). AP was induced in Sprague-Dawley rats by giving two intraperitoneal injections of l-Arg, each at concentrations of 250mg/100g body weight, with an interval of 1h. Hydrogen-rich saline (>0.6mM, 6ml/kg) or saline (6ml/kg) was administered, respectively, via tail vein 15min after each l-Arg administration. Severity of AP was assessed by analysis of serum amylase activity, pancreatic water content and histology. Samples of pancreas were taken for measuring malondialdehyde and myeloperoxidase. Apoptosis in pancreatic acinar cell was determined with terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling technique (TUNEL). Expression of proliferating cell nuclear antigen (PCNA) and nuclear factor kappa B (NF-kappaB) were detected with immunohistochemistry. Hydrogen-rich saline treatment significantly attenuated the severity of l-Arg-induced AP by ameliorating the increased serum amylase activity, inhibiting neutrophil infiltration, lipid oxidation and pancreatic tissue edema. Moreover, hydrogen-rich saline treatment could promote acinar cell proliferation, inhibit apoptosis and NF-kappaB activation. These results indicate that hydrogen treatment has a protective effect against AP, and the effect is possibly due to its ability to inhibit oxidative stress, apoptosis, NF-kappaB activation and to promote acinar cell proliferation.

Nonfunctional parathyroid carcinoma.

PURPOSE: Nonfunctional parathyroid carcinoma (PTC) is one of the rarest malignant diseases and only nine cases have been reported during the last 23 years. We present a case of nonfunctioning PTC and review the literature in an effort to provide a better understanding of this rare disorder. METHODS: One patient with nonfunctioning PTC was presented, detailing the clinical features, histologic findings, diagnosis, and treatment. Together with data from the other nine cases reported last 23 years, the related literature is also reviewed. RESULTS: The presented case was a 47-year-old man with a 2-month history of an enlarging painless cervical mass followed by a 2-week history of hoarseness. Clinical and laboratory evaluations failed to reveal evidence of hyperparathyroidism. Pathological analysis of the resected tumor disclosed findings consistent with PTC. The nonsecretory state of the tumor was further supported by immunoreactivity for parathyroid hormone in tissue, and normal serum levels of this peptide and calcium preoperatively and postoperatively. CONCLUSION: Most nonfunctional PTC is detected late due to a paucity of symptoms, of which a palpable neck mass is the most common. Patients with nonfunctioning PTC appear to have a poorer prognosis than do those with functioning parathyroid cancers.

Activation and clinical significance of p38 MAPK signaling pathway in patients with severe trauma.

BACKGROUND: Organ dysfunction or multiple organ dysfunction syndrome caused by developing immunological dysfunction and subsequent sepsis or the systemic inflammatory response syndrome after trauma is the leading cause of death in trauma patient. It is believed that mitogen-activated protein kinase) (p38MAPK) is one of the most important kinases in inflammatory signaling. In this study, the change of p38 MAPK signaling pathway in trauma patient with different severity and its clinical significance in trauma inflammation were investigated. METHODS: One hundred fifty major trauma patients were included in the study and divided into three groups according to injury severity score (ISS). All data required to calculate ISS and determine organ function were registered on admission and during the ICU-stay. Peripheral blood samples were collected from trauma patients 6 h, 1 d, 3 d, 5 d, and 7 d after injury. RQ-PCR and Western blot was used to examine the changes in gene expression, protein expression, and activation level of leukocyte p38 MAPK. Plasma IL-6 and TNFalpha were assayed by ELISA. RESULTS: Organ dysfunction in 33 trauma patients developed and eight deaths occurred after 24 h in ICU. The causes of death included severe ARDS, MODS, and irreversible brain injury. Incidence of organ dysfunction was related to the increase of injury severity (P < 0.01). Compared with healthy control, the gene expression of p38 MAPK in trauma patients increased significantly 6 h after injury (P < 0.05), and reached a maximum in 1 d (P < 0.01). The expression maintained a high level for 7 d (P < 0.05). One day after injury, significant elevation was observed in protein expression and activation level of p38 MAPK (P < 0.05), as well as the plasma TNFalpha and IL-6 level (P < 0.01). Further investigation found that the gene expression, protein expression, and activation levels of p38 MAPK increased with higher ISS (P < 0.05), and the elevation of plasma TNFalpha and IL-6 level was associated with the increase of activated p38 MAPK and ISS (P < 0.05). CONCLUSION: p38 MAPK signal pathway was activated in trauma patients. The severity of trauma had highly positive correlation with the expression and activation of p38 MAPK, as well as the elevation of plasma TNFalpha and IL-6 expression. These findings indicate that p38 MAPK signaling pathway plays an important role in the pathological mechanism of trauma.

CTLA-4 +49A>G polymorphism is associated with the risk but not with the progression of colorectal cancer in Chinese.

PURPOSE: Colorectal cancer (CRC) is one of the most common malignancies in the world and a multipathway disease. Cytotoxic T-lymphocyte antigen-4 (CTLA-4) is a potent immunoregulatory molecule that suppresses antitumor response by down-regulating T-cell activation. The most studied +49A>G polymorphism of CTLA-4 gene has been associated with several autoimmune or cancer diseases. Our aim was to investigate the association between this genetic variant and the risk as well as progression of colorectal cancer in Chinese. METHODS: We conducted a case-control study of 124 colorectal cancer cases and 407 healthy controls. DNA was extracted from blood specimens, and +49A>G polymorphism in the CTLA-4 gene was genotyped by polymerase chain reaction-ligation detection reaction (PCR-LDR). RESULTS: In our study group, the frequency of AG or GG or carrying at least one G allele at position +49 was significantly different in colorectal cancer patients and the control group, indicating that the risk of CRC was significantly higher among subjects with the AG or GG genotype or carrying at least one G allele at position +49 than among the subjects with the AA genotype. However, we observed no association between CTLA-4 +49A>G polymorphism and the progression of CRC. Interestingly, the CTLA-4 +49A allele was in non-significantly higher numbers in CRC patients with distant metastasis. CONCLUSIONS: Our results suggested that CTLA-4 +49A>G polymorphism was associated with an increased risk of colorectal cancer, but this polymorphism did not play an important role in the progression of CRC in Chinese.

Prospective clinical trials of thyroidectomy with LigaSure vs conventional vessel ligation: a systematic review and meta-analysis.

OBJECTIVE: To evaluate the hemostatic effects and safety of thyroidectomy performed using the LigaSure vessel-sealing device (Valleylab, Boulder, Colorado) or the conventional vessel ligation. DATA SOURCES: The MEDLINE, EMBASE, Elsevier, SpringerLink, Ovid, and Cochrane Library electronic databases as well as the LigaSure manufacturer's Web site were searched for studies published between 1996 and 2008. No language restrictions were applied. STUDY SELECTION: Prospective, controlled clinical trials, both randomized and nonrandomized, comparing the hemostatic effects and safety of thyroidectomy using LigaSure and conventional vessel ligation were selected. DATA EXTRACTION: Data regarding operative parameters, duration of the operation, amount of intraoperative blood loss, length of hospital stay, and any postoperative complications were entered and analyzed using dedicated software from the Cochrane Collaboration. DATA SYNTHESIS: Four randomized and 5 nonrandomized trials that met selection criteria reported data from 927 patients, of whom 467 (50.4%) underwent LigaSure and 460 (49.6%) underwent conventional thyroidectomy. Operative duration (weighted mean difference [WMD], -11.97 minutes; 95% confidence interval [CI], -16.42 to -7.53 minutes) was significantly reduced with LigaSure thyroidectomy (P < .001). When LigaSure was used, operative time reductions of 20.32 minutes (95% CI, -33.86 to -6.79 minutes) for total thyroidectomy (P = .003) and 21.74 minutes (-38.32 to -5.16 minutes) for subtotal thyroidectomy (P = .01) were also confirmed with subgroup analysis. However, differences in the amount of intraoperative blood loss (WMD, -25.13 mL; 95% CI, -68.45 to 18.18 mL; P = .26), length of hospital stay (WMD, -0.08 days; 95% CI, -0.23 to 0.08 days; P = .31), and postoperative complication rates (odds ratio, 0.91; 95% CI, 0.61-1.04; P = .65) were not statistically significant for LigaSure vs conventional thyroidectomy. CONCLUSIONS: The LigaSure technique may provide a safe, effective, and fast alternative to conventional vessel ligation in thyroidectomy and may result in a significant reduction in operative duration. However, it may not confer any advantage over conventional thyroidectomy in terms of the amount of intraoperative blood loss, length of hospital stay, and postoperative complication rates.

Laparoscopic management of recurrent adhesive small-bowel obstruction: Long-term follow-up.

PURPOSE: To evaluate the efficiency, safety, and outcome of laparoscopic adhesiolysis for recurrent small-bowel obstruction (SBO), when performed early after failed conservative treatment. METHODS: Between 1999 and 2005, elective laparoscopic adhesiolysis was attempted in 46 patients with recurrent SBO after abdominal or pelvic surgery. Laparoscopic adhesiolysis was done during the acute onset of SBO after the patient failed to respond to 24 h of conservative treatment. RESULTS: Fifteen patients (32.6%) presented with recurrent SBO and 31 patients (67.4%) presented with recurrent SBO and chronic abdominal pain. Postoperative adhesions were identified laparoscopically in all patients: as isolated bands in 11 patients, enteroperitoneal angulation in 12 patients, entero-enteral angulation in 17 patients, and extensive dense and matted intra-abdominal adhesions in 6 patients. Successful complete laparoscopic adhesiolysis was achieved in 42 of the 46 patients (91.3%). Conversion to minilaparotomy was required for a convoluted mass of adherent bowel in one patient (2.2%) and laparotomy was required for extensive dense and matted adhesions in three patients (6.5%). The mean follow-up was 46.5 months (range 24-89 months). Forty-three patients (93.5%) were asymptomatic after the operation. Only one patient (2.2%) had a further two episodes of SBO over 38 months of follow-up. CONCLUSION: Laparoscopic intervention, when done early after the onset of symptoms, is highly feasible, safe, and effective in selected patients with recurrent SBO caused by postoperative adhesion.