Development and Characterization of the Recombinant Human VEGF-EGF Dual-Targeting Fusion Protein as a Drug Delivery System.

The design, preparation, as well as structural and functional characterizations of the recombinant fusion protein hVEGF-EGF as a dual-functional agent that may target both EGFR (R: receptor) and angiogenesis are reported. hVEGF-EGF was found to bind to EGFR more strongly than did EGF, and to bind to VEGFR similarly to VEGF. Mass spectrometry measurements showed that the sites of DTPA (diethylenetriaminepentaacetic acid) conjugated hVEGF-EGF (for radiolabeling) were the same as those of its parent hEGF and hVEGF proteins. All DTPA-conjugated proteins retained similar binding capacities to their respective receptors as compared to their respective parent proteins. In vitro cell binding studies using BAEC (a bovine aortic endothelial cell) and MDA-MB-231 (a human breast cancer) cells expressing both EGFR and VEGFR confirmed similar results. Treating BAEC cells with hVEGF-EGF induced remarkable phosphorylation of EGFR, VEGFR, and their downstream targets ERK1/2. Nevertheless, the radiolabeled (111)In-DTPA-hVEGF-EGF showed cytotoxicity against MDA-MB-231 cells. Pharmacokinetic studies using (111)In-DTPA-hVEGF-EGF in BALB/c nude mice showed that appreciable tracer activities were accumulated in liver and spleen. In all, this study demonstrated that the fusion protein hVEGF-EGF maintained the biological specificity toward both EGFR and VEGFR and may be a potential candidate as a dual-targeting moiety in developing anticancer drugs.

A DNA vaccine against cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) prevents tumor growth.

Co-stimulatory signaling pathway triggered by the binding of B7.1/B7.2 (CD80/86) of antigen-presenting cells (APCs) to CD28 of T cells is required for optimal T-cell activation. Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) is a negative regulator of T cell activation, which competes with CD28 for B7.1/B7.2 binding with a greater affinity. Ipilimumab, a monoclonal antibody against CTLA-4, has shown positive efficacy in a pivotal clinical trial for the treatment of metastatic melanoma and was approved by FDA. However, the cost of monoclonal antibody-based therapeutics might limit the number of patients treated. To develop a novel therapeutics specifically targeting CTLA-4, we constructed a DNA vaccine by cloning the sequence of CTLA-4 fused with a transmembrane domain sequence of placental alkaline phosphatase (PLAP) into a mammalian expression plasmid, pVAC-1. Immunization with the resulting construct, pVAC-1-hCTLA-4, elicited antibody specific to human CTLA-4 with cross reactivity to murine CTLA-4, which was sufficient for inhibiting B16F10 tumor growth in c57BL/6 mice in the absence of measurable toxicity. Coupling liposome with pVAC-1-mCTLA-4 could break tolerance to self-antigen in BALB/c mice and induce potent immunity against murine CTLA-4, and suppress growth of subcutaneous renal cell carcinoma (Renca).

Flexor pollicis longus tendon rupture: a case series on palmaris longus tendon graft reconstruction after volar plate fixation.

Flexor pollicis longus (FPL) tendon rupture is a debilitating condition that can impair hand function. This case series study aimed to evaluate the outcomes of FPL tendon rupture and subsequent palmaris longus (PL) tendon graft reconstruction. Three cases of FPL tendon rupture in patients who had previously undergone open reduction and internal fixation with a volar plate were included. The surgical intervention involved volar plate removal, tenolysis and PL tendon graft reconstruction. Follow-up assessments showed gradual improvement in wrist function, with no post-operative complications or infections observed. These findings suggest that PL tendon grafting can be an effective surgical technique for FPL tendon rupture. Further research is needed to determine optimal surgical approaches and post-operative rehabilitation protocols for this condition.

5-Fluorocytosine combined with Fcy-hEGF fusion protein targets EGFR-expressing cancer cells.

Human epithelial cancers account for approximately 50% of all cancer deaths. This type of cancer is characterized by excessive activation and expression of the epidermal growth factor receptor (EGFR). The EGFR pathway is critical for cancer cell proliferation, survival, metastasis and angiogenesis. The EGF-EGFR signaling pathway has been validated as an important anticancer drug target. Increasing numbers of targeted therapies against this pathway have been either approved or are currently under development. Here, we adopted a prodrug system that uses 5-fluorocytosine (5-FC) and human EGF (hEGF) fused with yeast cytosine deaminase (Fcy) to target EGFR-overexpressing cancer cells and to convert 5-FC to a significantly more toxic chemotherapeutic, 5-fluorouracil (5-FU). We cloned and purified the Fcy-hEGF fusion protein from Pichia pastoris yeast. This fusion protein specifically binds to EGFR with a similar affinity as hEGF, approximately 10 nM. Fcy-hEGF binds tightly to A431 and MDA-MB-468 cells, which overexpress EGFR, but it binds with a lower affinity to MDA-MB-231 and MCF-7, which express lower levels of EGFR. Similarly, the viability of EGFR-expressing cells was suppressed by Fcy-hEGF in the presence of increasing concentrations of 5-FC, and the IC(50) values for A431 and MDA-MB-468 were approximately 10-fold lower than those of MDA-MB-231 and MCF-7. This novel prodrug system, Fcy-hEGF/5-FC, might represent a promising addition to the available class of inhibitors that specifically target EGFR-expressing cancers.

Honokiol inhibits hypoxia-inducible factor-1 pathway.

PURPOSE: Hypoxia-inducible factor-1α (HIF-1α) plays a pivotal role in the reaction of a tumour to hypoxia. In this study, we examined the inhibitory effect of a natural compound, honokiol, on HIF-1α activity and tumour growth in combination with radiation. METHODS: The inhibitory effect of honokiol on hypoxia-responsive element (HRE) controlled luciferase activity and HIF-1α accumulations stimulated by CoCl(2), or hypoxia was examined. Effect of honokiol on HIF-1α levels within hypoxic tumour microenvironment was investigated by immunohistochemical and in vivo bioluminescent studies. The in vivo radiosensitising activity of honokiol was evaluated with subcutaneous murine colon carcinoma, CT26, xenografts of BALB/c mice treated with honokiol, radiation, or both. RESULTS: Suppression of luciferase (luc) activity in HRE-luc stable cells by honokiol was in agreement with the results of decreased HIF-1α accumulation. In CT26-HRE-luc tumour-bearing mice, the inhibitory effect of intraperitoneally injected honokiol on HIF-1α-regulated luciferase activities induced by either CoCl(2) or radiation could be monitored non-invasively. Lastly, honokiol in combination with irradiation produced synergistic delay of CT26 tumour growth. CONCLUSIONS: Our data suggest that honokiol can exert its anticancer activity as a HIF-1α inhibitor by reducing HIF-1α protein level and suppressing the hypoxia-related signaling pathway. The animal experiment indicates that honokiol improves the therapeutic efficacy of radiation.