Ruiyu Zhu

Acquisition of paclitaxel resistance via PI3K‑dependent epithelial‑mesenchymal transition in A2780 human ovarian cancer cells.

Epithelial ovarian cancer is a major cause of mortality among women with gynecological malignancies. Paclitaxel is commonly used for chemotherapy of ovarian cancer, yet its efficacy is limited by chemoresistance. Generally, drug resistance is associated with acquisition of the epithelial-mesenchymal transition (EMT) in cancer. The aim of the present study was to determine whether the EMT is involved in acquired resistance to paclitaxel in A2780 human ovarian cancer cells. Using the paclitaxel-resistant A2780/PTX cell line, we examined the cellular morphology, molecular changes, migration and proliferation consistent with the EMT. Furthermore, we found that inhibition of phosphatidylinositol 3-kinase (PI3K) activity reduced the proliferation and migration and restored their sensitivity to paclitaxel. Our study provides new insights into EMT-like phenotypic changes that are linked to paclitaxel resistance in A2780 cells. We believe that inhibition of the PI3K signaling pathway could provide a novel therapeutic approach to overcome chemoresistance and prevent metastasis during paclitaxel chemotherapy.

Expression and purification of recombinant human serum albumin fusion protein with VEGF165b in Pichia pastoris

VEGF165b is an endogenous transcriptional splice variant of VEGF and has been shown to have a therapeutic potency as an anti-cancer agent. In this report, a fusion gene consisting of a human VEGF165b and a human albumin (HSA) gene was constructed and then inserted into a pPIC9k vector. The recombinant fusion protein, rhHSA-VEGF165b, was over expressed in the methylotrophic yeast Pichia pastoris under the control of AOX1 promoter. After induction with methanol, the expression level of rhHSA-VEGF165b was 275 mg/L in broth. The fusion protein rhHSA-VEGF165b was purified to more than 95% purity by using Blue Sepharose Fast Flow and SP Sepharose Fast Flow. Biological activity of the prepared rhHSA-VEGF165b was characterized by transwell migration assay, retaining about 9% of that of unmodified rhVEGF165b on a molar basis. Data from mice show that the serum half-life time of rhHSA-VEGF165b was nearly 20 times longer than that of rhVEGF165b.

Recombinant disintegrin domain of ADAM15 inhibits the proliferation and migration of Bel-7402 cells

ADAM15 (A Disintegrin And Metalloproteinase 15), a transmembrane protein containing seven domains, interacts with some integrins via its disintegrin domain and overexpresses in many solid tumors. In this study, the effect of the recombinant human disintegrin domain (rhddADAM15) on the proliferation and migration of Bel-7402 cells was evaluated in vitro and in vivo in zebrafish xenografts. rhddADAM15 (4 μM) severely inhibited the proliferation and migration of Bel-7402 cells, inducing a partial G2/S arrest and morphological nucleus changes of apoptosis. Moreover, the activity of caspases 8, 9 and 3 in Bel-7402 cells was increased. In addition, the zebrafish was used as a model for apoptosis-induction and tumor-xenograft. rhddADAM15 (1 pM) inhibited the growth and metastasis of Bel-7402 cell xenografts in zebrafish and a lower concentration (0.1 pM) induced severe apoptosis in the somatic cells of zebrafish. In conclusion, our data identified rhddADAM15 as a potent inhibitor of tumor growth and metastasis, making it a promising tool for use in anticancer treatment.

Antitumor and anti‑angiogenic activity of the recombinant human disintegrin domain of A disintegrin and metalloproteinase 15

A disintegrin and metalloproteinases (ADAMs), a family of transmembrane glycoproteins, are expressed in numerous tissues and organs, and have been implicated in a variety of physiological and pathological processes. ADAM15 is unique among the ADAMs in having an Arg-Gly-Asp motif in its disintegrin domain. In the present study, the antitumor and anti-angiogenic effects of the recombinant human disintegrin domain (rhdd) ADAM15, expressed by Escherichia coli, were evaluated. rhddADAM15 inhibited the proliferation and migration of several tumor cells, with a half maximal inhibitory concentration of 1.0-6.0 µM. In addition, rhddADAM15 inhibited the proliferation of Bel-7402 cells via the mitogen-activated protein kinase pathway and reduced the activation of Src. rhddADAM15 (1-10 µM) inhibited the proliferation, migration and tube formation of vascular endothelial EA.hy926 cells. G0/G1 arrest (10.96 ± 1.40%) and apoptotic cells (55.85 ± 1.06%) were observed in the EA.hy926 cells treated with 4 µM and 6 µM rhddADAM15, respectively. In vivo, rhddADAM15 significantly inhibited angiogenesis in zebrafish. rhddADAM15 at concentrations of 20 nmol/fish or 5 nmol/fish inhibited the angiogenesis of subintestinal and intersegmental vessels in the zebrafish by 72 ± 1.26 and 48 ± 2.92%, respectively. In conclusion, the results of the present study identified rhddADAM15 as a potent inhibitor of tumor formation and angiogenesis, rendering it a promising tool for use in anticancer treatment.

Cost-effective production of recombinant human interleukin 24 by lactose induction and a two-step denaturing and one-step refolding method

Abstract Recombinant human interleukin 24 (rhIL24) is a member of the interleukin 10 (IL10) family of cytokines with novel therapeutic properties. Human IL24 possesses three N glycosylation sites and a disulfide bridge. The cost and composition of culture media is critical for commercial-scale production of recombinant proteins in E. coli. Addition of yeast extract and glucose to medium enhances rhIL24 production, and the use of lactose instead of IPTG for induction drops the cost and decreases toxicity. In addition, a two-step denaturing and one-step refolding (2DR) strategy improves rhIL24 production. The 2DR strategy replaces a more conventional approach for protein solubilization and refolding. LC–MS/MS provides definitive identification and quantitative information on rhIL24. Single-step purified rhIL24 displayed biological activity on HepG2 hepatocellular carcinoma cells, but no effect on L02 cells. Proliferation analysis suggests that rhIL24 may have potential use as a medication. In the present study, we developed a simple process for producing quality product with high purity. The expression and purification of rhIL24 described here may be a step towards inexpensive large-scale production.

La Autoantigen Induces Ribosome Binding Protein 1 (RRBP1) Expression through Internal Ribosome Entry Site (IRES)-Mediated Translation during Cellular Stress Condition

The function of ribosome binding protein 1 (RRBP1) is regulating the transportation and secretion of some intracellular proteins in mammalian cells. Transcription of RRBP1 is induced by various cytokines. However, few studies focused on the process of RRPB1 mRNA translation. The RRBP1 mRNA has a long 5′ untranslated region that potentially formed a stable secondary structure. In this study, we show that the 5′ UTR of RRBP1 mRNA contains an internal ribosome entry site (IRES). Moreover, the RRBP1 expression is induced by chemotherapeutic drug paclitaxel or adriamycin in human hepatocellular carcinoma cells and accompanied with the increased expression of La autoantigen (La), which binds to RRBP1 IRES element and facilitates translation initiation. Interestingly, we found IRES-mediated RRBP1 translation is also activated during serum-starvation condition which can induce cytoplasmic localization of La. After mapping the entire RRBP1 5′ UTR, we determine the core IRES activity is located between nt-237 and -58. Furthermore, two apical GARR loops within the functional RRBP1 IRES elements may be important for La binding. These results strongly suggest an important role for IRES-dependent translation of RRBP1 mRNA in hepatocellular carcinoma cells during cellular stress conditions.