Application of modified closed biopsy in rabbit model of VX2-transplanted bone tumor.

BACKGROUND: This study was aimed to explore the application value of modified closed biopsy technique in puncture biopsy of rabbit VX2 transplanted bone tumor model. METHODS: VX2 tumor was transplanted into the bilateral tibia of 30 rabbits through the tibial plateau to make the model of VX2 transplanted bone tumor. Seven days after modeling, the proximal tibia biopsy was performed under the guidance of X-ray, and the biopsy specimen was examined pathologically. The left leg was biopsied with modified closed biopsy technique (experimental group), and the right leg was biopsied with hollow needle (control group). After 14 days of modeling, all rabbits were killed after X-ray examination around the puncture hole, and the soft tissue around the puncture hole was taken for pathological examination, and the expression levels of PCNA and CD34 in the tissue extract were detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: By the end of the experiment, a total of 3 rabbits died, and finally, 27 rabbits were included in the study. Tumor cells were detected in all the intramedullary specimens obtained by puncture biopsy. On the 14th day after modeling, X-ray showed that the occurrence rate of periosteal reaction and extraosseous high-density shadow around the puncture hole was 14.81% (4/27) in the experimental group and 40.74% (11/27) in the control group. The difference was statistically significant (P<0.05). The pathological results of soft tissue around the puncture hole showed that the tumor cell metastasis rate was 29.63% (8/27) in the experimental group and 100% (27/27) in the control group, and the difference was statistically significant (P<0.05). The expression levels of PCNA and CD34 in the experimental group were lower than those in the control group (P < 0.05). CONCLUSION: Both the modified closed biopsy technique and needle aspiration biopsy can provide sufficient biopsy tissue for the diagnosis of VX2-transplanted bone tumor in rabbits. At the same time, the improved closed biopsy technique has a certain application value in preventing local metastasis of tumor cells along the puncture channel.

A ligand-based and enediyne-energized bispecific fusion protein targeting epidermal growth factor receptor and insulin-like growth factor-1 receptor shows potent antitumor efficacy against esophageal cancer.

Recent studies have revealed that the epidermal growth factor receptor (EGFR) and insulin-like growth factor-1 receptor (IGF-1R) are overexpressed in various types of human tumors and are attractive targets for anticancer drugs. In the present study, the expression of EGFR and IGF-1R in esophageal squamous cell carcinoma (ESCC) and adjacent normal tissues in a tissue microarray was firstly detected by immunohistochemical staining. In addition, their co-overexpression was observed in 48 out of 75 (64%) patients. Based on the findings, the antitumor activity of an EGFR/IGF-1R bispecific and enediyne-energized fusion protein EGF-LDP-IGF-AE, which we constructed recently by fusing two ligands (EGF and IGF-1) with an enediyne antibiotic lidamycin (LDM), on ESCC were evaluated. Binding assay indicated that the EGF-LDP-IGF protein bound to esophageal cancer cells, and then internalized into the cytoplasm. In vitro, the enediyne­energized fusion protein EGF-LDP-IGF-AE exhibited extremely potent cytotoxicity to ESCC cells with IC50 values between 10-10 and 10-15 mol/l. In vivo, EGF-LDP­IGF-AE also markedly suppressed the growth of human KYSE450 xenografts by 75.1% when administered at 0.3 mg/kg in a nude mouse model, and its efficacy was significantly higher than that of LDM (at maximum tolerated dosage) and mono-specific counterparts. In addition, EGF-LDP-IGF-AE arrested cell cycle progression and it concentration-dependently induced cell apoptosis as well as inhibited the activation of EGFR/IGF-1R and two major downstream signaling pathways (PI3K/AKT and RAS/MAPK). These data imply the potential clinical application of EGF-LDP-IGF-AE for ESCC patients with EGFR and/or IGF-1R overexpression.

A bispecific enediyne-energized fusion protein targeting both epidermal growth factor receptor and insulin-like growth factor 1 receptor showing enhanced antitumor efficacy against non-small cell lung cancer.

Epidermal growth factor receptor (EGFR) and insulin-like growth factor 1 receptor (IGF-1R) both overexpressed on non-small cell lung cancer (NSCLC) and are known cooperatively to promote tumor progression and drug resistance. This study was to construct a novel bispecific fusion protein EGF-IGF-LDP-AE consisting of EGFR and IGF-IR specific ligands (EGF and IGF-1) and lidamycin, an enediyne antibiotic with potent antitumor activity, and investigate its antitumor efficacy against NSCLC. Binding and internalization assays showed that EGF-IGF-LDP protein could bind to NSCLC cells with high affinity and then internalized into cells with higher efficiency than that of monospecific proteins. In vitro, the enediyne-energized analogue of bispecific fusion protein (EGF-IGF-LDP-AE) displayed extremely potent cytotoxicity to NSCLC cell lines with IC50<10-11 mol/L. Moreover, the bispecific protein EGF-IGF-LDP-AE was more cytotoxic than monospecific proteins (EGF-LDP-AE and LDP-IGF-AE) and lidamycin. In vivo, EGF-IGF-LDP-AE markedly inhibited the growth of A549 xenografts, and the efficacy was more potent than that of lidamycin and monospecific counterparts. EGF-IGF-LDP-AE caused significant cell cycle arrest and it also induced cell apoptosis in a dosage-dependent manner. Pretreatment with EGF-IGF-LDP-AE inhibited EGF-, IGF-stimulated EGFR and IGF-1R phosphorylation, and blocked two main downstream signaling molecules AKT and ERK activation. These data suggested that EGF-LDP-IGF-AE protein would be a promising targeted agent for NSCLC patients with EGFR and/or IGF-1R overexpression.