A human/murine chimeric fab antibody neutralizes anthrax lethal toxin in vitro.

Human anthrax infection caused by exposure to Bacillus anthracis cannot always be treated by antibiotics. This is mostly because of the effect of the remaining anthrax toxin in the body. Lethal factor (LF) is a component of lethal toxin (LeTx), which is the major virulence of anthrax toxin. A murine IgG monoclonal antibody (mAb) against LF with blocking activity (coded LF8) was produced in a previous study. In this report, a human/murine chimeric Fab mAb (coded LF8-Fab) was developed from LF8 by inserting murine variable regions into human constant regions using antibody engineering to reduce the incompatibility of the murine antibody for human use. The LF8-Fab expressed in Escherichia coli could specifically identify LF with an affinity of 3.46 × 10(7) L/mol and could neutralize LeTx with an EC50 of 85 µ g/mL. Even after LeTx challenge at various time points, the LF8-Fab demonstrated protection of J774A.1 cells in vitro. The results suggest that the LF8-Fab might be further characterized and potentially be used for clinical applications against anthrax infection.

Trop2 inhibition of P16 expression and the cell cycle promotes intracellular calcium release in OSCC.

Trop2 is an intracellular calcium signal transducer and a prognostic biomarker in many cancers. P16 is a cell cycle gene that negatively regulates cell proliferation and division in most human cancers. Oral squamous cell carcinoma (OSCC) is a common malignant tumor subgroup of head and neck squamous cell carcinoma worldwide. Both Ca2+-dependent and cell cycle signaling pathways play vital roles in OSCC, although the molecular mechanisms remain to be elucidated. We aimed to examine the function of Trop2 and P16 in regulating intracellular calcium ions and the cell cycle in OSCC cell lines. Furtherly, the mRNA and protein expression levels of Trop2 and P16 in OSCC tissue samples were assessed, and their function was evaluated as potential clinical prognostic biomarkers. Trop2 promoted intracellular calcium ion release in OSCC and induced S phase of the cell cycle. Moreover, Trop2-mediated Ca2+ inhibited P16 expression through the AMP-activated protein kinase pathway in OSCC. Interestingly, P16 overexpression could not reverse these phenomena in vitro. We also demonstrated that human OSCC tissues showed high Trop2 mRNA and protein expression, and Trop2+/P16- expression is an independent prognostic marker for OSCC patients. Our data suggest that Trop2+/P16- may be a valuable prognostic marker for OSCC and that Trop2 inhibits P16 expression and induces S phase by promoting intracellular calcium release in OSCC.

In vitro evaluation of the hepatic lipid accumulation of bisphenol analogs: A high-content screening assay.

Bisphenol A (BPA) has a variety of adverse effects on human health; therefore, BPA analogs are increasingly used as replacements. Notably, recent studies have revealed that BPA exposure induced hepatic lipid accumulation, but few studies are available regarding the similar effects of other bisphenol analogues (BPs). Thus, in the present study, a high-content screening (HCS) assay was performed to simultaneously evaluate the hepatic lipid accumulation of 13 BPs in vitro. The BPs induced lipid deposition in HepG2 cells ranking as below: 4,4'-thiodiphenol (TDP) < bisphenol S (BPS) < 4,4'-dihydroxybenzophenone (DHBP) < tetrabromobisphenol A (TBBPA) < tetrachlorobisphenol A (TCBPA) < bisphenol E (BPE) < bisphenol F (BPF) < bisphenol B (BPB) < bisphenol AF (BPAF) < bisphenol A (BPA) < bisphenol C (BPC) < tetramethylbisphenol A (TMBPA) < bisphenol AP (BPAP). Meanwhile, Oil Red O staining and triacylglycerol detection further validated the lipid accumulation elicited by the latter 8 BPs, which exhibited the more significant effects on lipid deposition. Mechanistically, significantly increased expressions of genes involved in fatty acid synthesis and nuclear receptors and decreased levels of genes associated with fatty acid ß-oxidation were observed under BPs treatment. Therefore, the present work is the first to systematically provide direct evidence for BPs-induced hepatic lipid accumulation in vitro via HCS, which can be helpful for safety assessments of BPs.

Elevated epiregulin expression predicts poor prognosis in gastric cancer.

Epiregulin (EREG) is a novel family member of EGF-like ligands and have elevated expression in a variety of human cancers. EREG expression promotes tumor progression and metastasis and reduces patient survival. However, the expression of EREG and its prognostic value are not clear in gastric cancer (GC). We assessed EREG mRNA and protein expression in GC tissues from Chinese patients using quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemical staining of tissue microarray, and analyzed the correlation between the level of EREG expression and patient clinical characteristics and prognosis. We found that EREG expression was significantly higher in GC tissues than in matched adjacent noncancerous tissues. High EREG protein expression in GC was significantly associated with TNM stage including tumor size, lymph node metastases and distant metastases as well as poor overall survival. These finding demonstrate that EREG is an independent prognostic biomarker for GC.

[Expression of KISS-1 and GnRH in rat hypothalamus].

OBJECTIVE: To assay the expression of KiSS-1 and GnRH in the male rat hypothalamus at different developmental stages, and to explore the significance of KiSS-1 in sex development onset and normal reproduction regulation. METHODS: Expression analyses of KiSS-1 and GnRH genes were conducted in the rat hypothalamus at different developmental stages with RT-PCR and real time-PCR. The testosterone level was assayed by chemoluminescence technique. RESULTS: KiSS-1 mRNA rose gradually during sex development in the rat hypothalamus, highest at puberty and lowered a little at adulthood. KiSS-1 mRNA of the prepubertal, early pubertal, pubertal and adult rats was 1.7, 2.1, 3.5 and 2.0 times higher than that of the infantile rats respectively. The expression of GnRH and KiSS-1 correlated positively (r = 0.905, P < 0.05). But the activation of GnRH neuron was later than KiSS-1. The expression of GnRH was the highest in the puberty rats. GnRH mRNA of the prepubertal, early pubertal, pubertal and adult rats was 1.1, 1.94, 2.42 and 1.92 times higher than that of the infantile rats respectively. The level of testosterone in the adult rats was significantly higher than that at the earlier stage and was the highest at the adult stage. CONCLUSION: The expression of KiSS-1 correlates positively with that of GnRH. KiSS-1 may participate in the regulation of GnRH and is relevant to puberty onset and the regulation of reproduction function.

Correlation between Trop2 and amphiregulin coexpression and overall survival in gastric cancer.

Gastric cancer (GC) is a multistep and multistage disease and the majority of GC cells could overexpressed one or more oncogenes. Trop2 and amphiregulin (AREG) are both overexpressed in various epithelial cell cancers and have the role in the increases tumor cells division and metastasis. However, little is known about the function and correlation of two oncogenes coexpressed in GC. The expression level of these two genes in 791 cases of GC tissues were tested, the correlations between two genes expression and clinical pathological characteristics and overall survival in GC patients through immunohistochemistry (IHC) were analyzed. This study also explored the mRNA expression level of two genes in 26 cases of freshly GC tissues by qRT-PCR. The results indicated that Trop2+/AREG+ coexpression was higher in GC tissues than in adjacent tissues. Trop2+/AREG+ protein coexpression were associated with Tumor Node Metastasis (TNM) stage (χ2  = 50.345, P < 0.001), tumor size (χ2  = 40.349, P < 0.001), lymph node metastases (χ2  = 26.481, P < 0.001), and distant metastases (χ2  = 8.387, P = 0.039). GC patients with Trop2+ and AREG+ protein coexpression had poor overall survival rates (HR = 3.682, 95% CI = 2.038-6.654, P < 0.001). The expression level of Trop2/AREG were positively correlated (r 0.254 and P < 0.001). The result of the mRNA expression was similar to that of the protein expression. Overall, Trop2 and AREG could be seen as prognostic cobiomarker in GC and combined detection of Trop2 and AREG could be viewed as helpful in predicting the prognosis of the GC patients.

Trop2 is overexpressed in gastric cancer and predicts poor prognosis.

The cell surface protein Trop2 is overexpressed in a variety of human cancers. Trop2 expression increases tumor development and metastasis and reduces patient survival. However, little is known about the role of Trop2 expression and its prognostic value in gastric cancer (GC), particularly in Chinese populations. We analyzed Trop2 expression in GC tissues collected from Chinese GC patients. Quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry on tissue microarrays were performed to assess levels of Trop2 mRNA and protein in GC, and correlations between Trop2 expression and clinical characteristics and prognosis were analyzed. Trop2 expression was higher in GC tissues than in neighboring non-tumor tissues. Increased Trop2 protein levels in GC were associated with increased differentiation, tumor node metastasis stage, tumor size, lymph node metastasis, distant metastasis, and H. pylori infection. GC patients with high Trop2 expression also had poor overall survival rates. These data suggest Trop2 is a useful prognostic biomarker for GC.

Abnormal amphiregulin expression correlates with gastric cancer prognosis.

Gastric cancer (GC) is a global health issue with a high mortality rate. Early diagnosis and tracking of GC is a challenge due to a lack of reliable tools. Amphiregulin (AREG) is a member of the epidermal growth factor (EGF) family that activates growth signaling upon binding of EGF receptors. Elevated AREG expression is associated with various pathological conditions, including cancer. Here, we investigated whether increased AREG expression is a disease indicator and/or prognostic biomarker for GC. We used tissue microarray and quantitative real-time polymerase chain reaction to assess AREG expression in clinical tissue specimens at various stages of GC and a conducted bioinformatics analysis to evaluate the value of AREG over-expression as a GC biomarker. We found that both mRNA and protein expression of AREG were increased in the tissues of GC patients when compared to tissues from non-cancer patients or normal tissues. High expression of AREG was also associated with GC clinicopathological characteristics and poor survival. Thus, over-expression of AREG could serve as a novel GC biomarker, and active surveillance of its expression could be a novel approach to GC diagnosis and monitoring.

Prognostic value of decreased expression of RBM4 in human gastric cancer.

RNA-binding motif 4 (RBM4) is a multifunctional protein that participates in regulating alternative splicing and mRNA translation. Its reduced expression has been associated with poor overall survival in lung cancer, breast cancer and ovarian cancer. We assessed RBM4 protein expression levels with immunohistochemistry in tissue microarrays containing malignant gastric cancer tissues and benign tissues from 813 patients. We also examined the expression levels of RBM4 mRNA in twenty-five paired gastric cancer samples and adjacent noncancerous tissues. Both RBM4 protein and mRNA expression levels were significantly lower in gastric cancer tissues compared with the adjacent noncancerous tissues. There was a significant association between reduced RBM4 protein expression and differentiation (P < 0.001), lymph node metastasis (P = 0.026), TNM state (P = 0.014) and distant metastasis (P = 0.036). Patients with reduced RBM4 expression (P < 0.001, CI = 0.315-0.710) and TNM stage III and IV (P < 0.001, CI = 4.757-11.166) had a poor overall survival. These findings suggest that RBM4 is a new biomarker in gastric cancer, as the reduced expression of this protein is correlated with poor differentiation, lymph node status and distant metastasis. Further, lower RBM4 expression is an independent prognostic marker for gastric cancer.

A murine-human chimeric IgG antibody against vascular endothelial growth factor receptor 2 inhibits angiogenesis in vitro.

Vascular endothelial growth factor receptor 2 (VEGFR2) has been reported to play an important role in angiogenesis and tumorigenesis. A murine anti-VEGFR2 mAb (A8H1) has been established in a previous study. To reduce the incompatibility of the murine mAb for human use, the chimeric anti-VEGFR2-IgG was developed by genetic recombination of the variable regions of the A8H1 antibody and the constant regions of human IgG, and was expressed in Sp2/0 cells transfected with the two recombinant vectors containing the heavy chain and the light chain regions. After screening, clone 2F12 was selected and was found to stably secrete the murine-human chimeric anti-VEGFR2-IgG (coded 2F12). This chimeric IgG maintained the specificity and the affinity of the parental murine antibody against VEGFR2, and effectively identified VEGFR2 expressed on the surface of HUVECs and BEL-7402 cells. Furthermore, the 2F12 antibody demonstrated inhibition of angiogenesis in vitro, such as proliferation, migration, invasion and tube formation of HUVECs. This murine-human chimeric IgG may be considered for further development as an anti-angiogenesis and anti-tumor agent.

A human anti-c-Met Fab fragment conjugated with doxorubicin as targeted chemotherapy for hepatocellular carcinoma.

c-Met is over-expressed in hepatocellular carcinoma(HCC) but is absent or expressed at low levels in normal tissues. Therefore we generated a novel conjugate of a human anti-c-Met Fab fragment (MetFab) with doxorubicin (DOX) and assessed whether it had targeted antitumor activity against HCC and reduced the side-effects of DOX. The MetFab was screened from human phage library, conjugated with DOX via chemical synthesis, and the conjugation MetFab-DOX was confirmed by HPLC. The drug release patterns, the binding efficacy, and cellular distribution of MetFab-DOX were assessed. MetFab-DOX was stable at pH7.2 PBS while release doxorubicin quickly at pH4.0, the binding efficacy of MetFab-DOX was similarly as MetFab, and the cellular distribution of the MetFab-DOX is distinct from free DOX. The cytotoxicity of MetFab-DOX was analyzed by the MTT method and the nude mouse HCC model. The MetFab-DOX demonstrated cytotoxic effects on c-Met expressing-tumor cells, but not on the cells without c-Met expression. MetFab-DOX exerted anti-tumor effect and significantly reduced the side effect of free DOX in mice model. Furthermore, the localization of conjugate was confirmed by immunofluorescence staining of tumor tissue sections and optical tumor imaging, respectively, and the tissue-distribution of drug was compared between free DOX and MetFab-DOX treatment by spectrofluorometer. MetFab-DOX can localize to the tumor tissue, and the concentration of doxorubicin in the tumor was higher after MetFab-DOX administration than after DOX administration. In summary, MetFab-DOX can target c-Met expressing HCC cells effectively and have obvious antitumor activity with decreased side-effects in preclinical models of HCC.

Identification of two aberrant transcripts derived from a hybridoma with amplification of functional immunoglobulin variable genes.

Murine monoclonal antibodies (mAbs) are widely used but have limitations if administered in humans. The use of chimeric or humanized mAbs can reduce immunogenicity. The first step in producing such mAbs is to clone murine variable genes from a hybridoma, but it is possible to amplify both functional and aberrant variable genes, as they coexist in the hybridoma. During the development of a murine-human chimeric antibody, we have cloned from a hybridoma the functional heavy chain variable region (V(H)) and light chain variable region (V(L)) genes of a mAb that blocks the binding of anthrax lethal factor to protective antigen. In this study, we report the detection of two aberrant transcripts from a hybridoma produced using myeloma cell line OUR-1, the development of a method to distinguish between the functional and abundant aberrant V(L) transcripts, and the origins of these aberrant genes. The aberrant V(L) gene is derived from OUR-1 cells, while the aberrant V(H) gene might derive from antibody repertoires in B cells or from gene rearrangement in the hybridoma cells. The aberrant V(H) and V(L) genes in this study may facilitate discrimination between the functional and aberrant variable genes from hybridoma cells.

[Analysis of the main components of inner ear antigens inducing autoimmune Meniere's disease in guinea pigs].

OBJECTIVE: To investigate the main components of inner ear antigens inducing autoimmune Meniere's disease (AIMD) in guinea pigs. METHODS: The guinea pigs were immunized with isologous crude inner ear antigens (ICIEAg). Then, the hearing function was measured with auditory brainstem response (ABR), the vestibular function was measured with electronystagmography (including spontaneous nystagmus and caloric test), and inner ear histopathological changes were observed by inner ear celloidin section with haematoxylin-eosin staining and observed under light microscope. According to these results, the AIMD-model animals from non-AIMD-model ones were distinguished. The special antibodies against ICIEAg in sera were measured with ELISA. The antigen-antibody reactions against different components of ICIEAg were detected by Western blotting with sera of AIMD and non-AIMD guinea pigs respectively. Then, we analysed the contrast between them and found the main components of the ICIEAg that were positive reaction in AIMD guinea pigs and negative reaction in non-AIMD guinea pigs. RESULTS: The result of ELISA demonstrated that the sera of both the AIMD and non-AIMD guniea pigs contained the special antibodies against ICIEAg after immunized with ICIEAg. The difference of the amount of antibody against ICIEAg between AIMD guinea pig group and non-AIMD guinea pig group was not significant. Western blotting assay showed only the sera of AIMD guinea pig contained the antibodies against the specific antigens with the molecular of 68 000, 58 000, 42 000 and 28 000. CONCLUSIONS: ICIEAg contain many different components, the AIMD might only happen in the guinea pigs in which the special immunization against the main components that could induce this kind of disorder appeared. The inner ear antigens with molecular of 68 000, 58 000, 42 000 and 28 000 might be the main components inducing AIMD in guinea pigs.