Single-chain variable fragment antibody against human aspartyl/asparaginyl beta-hydroxylase expressed in recombinant Escherichia coli

The inhibitory effect of human umbilical cord mesenchymal stem cells expressing anti-HAAH scFv-sTRAIL fusion protein on glioma

Glioma is the most common malignant intracranial tumor with low 5-year survival rate. In this study, we constructed a plasmid expressing anti-HAAH single-chain antibody and sTRAIL fusion protein (scFv-sTRAIL), and explored the effects of the double gene modified human umbilical cord mesenchyreal stem cells (hucMSCs) on the growth of glioma in vitro and in vivo. The isolated hucMSCs were identified by detecting the adipogenic differentiation ability and the osteogenic differentiation ability. The phenotypes of hucMSCs were determined by the flow cytometry. The hucMSCs were infected with lentivirus expression scFv-sTRAIL fusion protein. The expression of sTRAIL in hucMSCs were detected by immunofluorescence staining, western blot and ELISA. The tropism of hucMSCs toward U87G cells was assessed by transwell assay. The inhibitory effect of hucMSCs on U87G cells were explored by CCK8 and apoptosis assay. The xenograft tumor was established by subcutaneously injection of U87G cells into the back of mice. The hucMSCs were injected via tail veins. The inhibitory effect of hucMSCs on glioma in vivo was assessed by TUNEL assay. The hucMSCs migrated into the xenograft tumor were revealed by detecting the green fluorescent. The results showed that the scFv-sTRAIL expression did not affect the phenotypes of hucMSCs. The scFv-sTRAIL expression promoted the tropism of hucMSCs toward U87G cells, enhanced the inhibitory effect and tumor killing effect of hucMSCs on U87G cells. The in vivo study showed that hucMSCs expressing scFv-sTRAIL demonstrated significantly higher inhibitory effect and tumor killing effect than hucMSCs expressing sTRAIL. The green fluorescence intensity in the mice injected with hucMSCs expressing scFv-sTRAIL was significantly higher than that injected with hucMSCs expressing sTRAIL. These data suggested that the scFv conferred the targeting effect of hucMSCs tropism towards the xenograft tumor. In conclusion, the hucMSCs expressing scFv-sTRAIL fusion protein gained the capability to target and kill gliomas cells in vitro and in vivo. These findings shed light on a potential therapy for glioma treatment.

Aspartate β-hydroxylase as a target for cancer therapy

As metastasis is a major cause of death in cancer patients, new anti-metastatic strategies are needed to improve cancer therapy outcomes. Numerous pathways have been shown to contribute to migration and invasion of malignant tumors. Aspartate β-hydroxylase (ASPH) is a key player in the malignant transformation of solid tumors by enhancing cell proliferation, migration, and invasion. ASPH also promotes tumor growth by stimulation of angiogenesis and immunosuppression. These effects are mainly achieved via the activation of Notch and SRC signaling pathways. ASPH expression is upregulated by growth factors and hypoxia in different human tumors and its inactivation may have broad clinical impact. Therefore, small molecule inhibitors of ASPH enzymatic activity have been developed and their anti-metastatic effect confirmed in preclinical mouse models. ASPH can also be targeted by monoclonal antibodies and has also been used as a tumor-associated antigen to induce both cluster of differentiation (CD) 8+ and CD4+ T cells in mice. The PAN-301-1 vaccine against ASPH has already been tested in a phase 1 clinical trial in patients with prostate cancer. In summary, ASPH is a promising target for anti-tumor and anti-metastatic therapy based on inactivation of catalytic activity and/or immunotherapy.

Aspartate β-hydroxylase disrupts mitochondrial DNA stability and function in hepatocellular carcinoma

The mechanism of aberrant mitochondrial genome and function in hepatocellular carcinoma (HCC) remains largely unknown. Our previous study demonstrated an increased expression of aspartate β-hydroxylase (ASPH) in HCC tissues, which was associated with tumor invasiveness and a worse prognosis. Currently, we unexpectedly observed the presence of ASPH in purified mitochondrial protein fraction. In addition, immunostaining of both exogenously and endogenously expressed ASPH showed a colocalization with mitochondrial biomarkers. This study aimed to investigate whether the mitochondrial ASPH is involved in mitochondrial malfunction in HCC. Our results showed that ASPH overexpression in HCC tissues was correlated with decreased copy numbers of displacement loop (D-loop) and NADH dehydrogenase subunit 1 (ND-1) and enhanced D-loop mutation, suggesting the disrupted mitochondrial DNA (mtDNA) stability. The reduced mtDNA copy numbers were associated with aggressive clinicopathological features of HCC. The loss of mtDNA integrity induced by enforced expression of ASPH was accompanied with mitochondrial dysfunction, which was characterized by the aberrant mitochondrial membrane potential, decreased ATP generation and enhanced reactive oxygen species. In contrast, knocking down ASPH by siRNA in HCC cell lines showed the opposite impact on mtDNA integrity and function. Mass spectrometry and co-immunoprecipitation further identified that ASPH interacted with histone H2A member X (H2AX). ASPH overexpression diminished the interaction between H2AX and mitochondrial transcription factor A (mtTFA), an important DNA-binding protein for mtDNA replication, which then reduced the binding of mtTFA to D-loop region. Collectively, our results demonstrate that ASPH overexpression disrupts the mtDNA integrity through H2AX-mtTFA signal, thereby affecting mitochondrial functions in HCC.

Preparation and Identification of a Single-chain Variable Fragment Antibody Against Canine Distemper Virus

The variable regions of the heavy chain (VH) and light chain (VL) were amplified by RT-PCR from the hybridoma 1N8, which secretes the monoclonal antibody against CDV N protein (aa 277-471). The VL and VH amplicons were combined using SOE-PCR by a 12 amino acid flexible linker (SSGGGGSGGGGS), which produced the scFv gene (named scFv/1N8). After sequence analysis, the scFv/1N8 gene was cloned into the prokaryotic expression vector PET32a with a His-tag. The recombinant scFv/1N8 protein was successfully expressed in recombinant Escherichia coli by IPTG induction. Moreover, the binding activity and specificity of the scFv were determined by indirect ELISA (His-tag) and competitive ELISA. The recombinant scFv/1N8 protein reported here will provide some basis for further antiviral drug research based on the scFv molecule.

Expression and Purification of the scFv from hybridoma cells secreting a monoclonal antibody against S PROTEIN of PEDV

The variable regions of the heavy chain (VH) and light chain (VL) were amplified by RT-PCR from the hybridoma 6E6, which secretes the monoclonal antibody against PEDV S protein. The VL and VH amplicons were combined using SOE-PCR by a 12 amino acid flexible linker (SSGGGGSGGGGS), which produced the scFv gene (named scFv/6E6). After sequence analysis, the scFv/6E6 gene was cloned into the prokaryotic expression vector pGEX-6p-1 with a GST-tag. The recombinant scFv/6E6 protein was successfully expressed in recombinant Escherichia coli by IPTG induction. Moreover, the recombinant scFv/6E6 protein was purified from the inclusion body form by the gel-cutting measure followed by electroelution and dialysis. The recombinant scFv/6E6 protein reported here will provide some basis for further antiviral drug research based on the scFv molecule.