A Rational Designed Novel Bispecific Antibody for the Treatment of GBM

Epidermal growth factor receptor variant III (EGFRvIII) is highly and specifically expressed in a subset of lethal glioblastoma (GBM), making the receptor a unique therapeutic target for GBM. Recently, bispecific antibodies (BsAbs) have shown exciting clinical benefits in cancer immunotherapy. Here, we report remarkable results for GBM treatment with a BsAb constructed by the “BAPTS” method. The BsAb was characterized through LC/MS, SEC-HPLC, and SPR. Furthermore, the BsAb was evaluated in vitro for bioactivities through FACS, antigen-dependent T-cell-mediated cytotoxicity, and a cytokine secretion assay, as well as in vivo for antitumor activity and pharmacokinetic (PK) parameters through immunodeficient NOD/SCID and BALB/c mouse models. The results indicated that the EGFRvIII-BsAb eliminated EGFRvIII-positive GBM cells by recruiting and stimulating effector T cells secreting cytotoxic cytokines that killed GBM cells in vitro. The results demonstrated the antitumor potential and long circulation time of EGFRvIII-BsAb in NOD/SCID mice bearing de2–7 subcutaneously heterotopic transplantation tumors and BALB/c mice. In conclusion, our experiments in both in vitro and in vivo have shown the remarkable antitumor activities of EGFRvIII-BsAb, highlighting its potential in clinical applications for the treatment of GBM. Additional merits, including a long circulation time and low immunogenicity, have also made the novel BsAb a promising therapeutic candidate.

Using ultrasound-targeted microbubble destruction to enhance radiotherapy of glioblastoma

Objective To investigate the efficacy and mechanism of ultrasound-targeted microbubble destruction (UTMD) combined with radiotherapy (XRT) on glioblastoma. Methods The enhanced radiosensitization by UTMD was assessed through colony formation and cell apoptosis in Human glioblastoma cells (U87MG). Subcutaneous transplantation tumors in 24 nude mice implanted with U87MG cells were randomly assigned to 4 different treatment groups (Control, UTMD, XRT, and UTMD + XRT) based on tumor sizes (100–300 mm3). Tumor growth was observed for 10 days after treatment, and then histopathology stains (HE, CD34, and γH2AX) were applied to the tumor samples. A TUNEL staining experiment was applied to detect the apoptosis rate of mice tumor samples. Meanwhile, tissue proteins were extracted from animal specimens, and the expressions of dsDNA break repair-related proteins from animal specimens were examined by the western blot. Results When the radiotherapy dose was 4 Gy, the colony formation rate of U87MG cells in the UTMD + XRT group was 32 ± 8%, lower than the XRT group (54 ± 14%, p < 0.01). The early apoptotic rate of the UTMD + XRT group was 21.1 ± 3% at 48 h, higher than that of the XRT group (15.2 ± 4%). The tumor growth curve indicated that the tumor growth was inhibited in the UTMD + XRT group compared with other groups during 10 days of observation. In TUNEL experiment, the apoptotic cells of the UTMD + XRT group were higher than that of the XRT group (p < 0.05). The UTMD + XRT group had the lowest MVD value, but was not significantly different from other groups (p > 0.05). In addition, γH2AX increased due to the addition of UTMD to radiotherapy compared to XRT in immunohistochemistry (p < 0.05). Conclusions Our study clearly demonstrated the enhanced destructive effect of UTMD combined with 4 Gy radiotherapy on glioblastoma. This could be partly achieved by the increased ability of DNA damage of tumor cells.

PREPARATION OF CINOBUFAGIN-LOADED BOVINE SERUM ALBUMIN NANOPARTICLES FOR HEPATOCARCINOMA THERAPY

Cinobufagin-loaded bovine serum albumin nanoparticles were prepared for treating hepatocellular carcinoma. In this report, cinobufagin-bovine serum albumin-nanoparticles (Cino-BSA-NP) were prepared by an aqueous desolvation process. The physicochemical properties, toxicity, and cancer-related applications of Cino-BSA-NP were investigated. Cino-BSA-NP had a uniform spherical morphology with a particle size in the range of 50–240 nm and an average size of 86.3 nm. The zeta potential of the nanoparticles was -49 mV. The overall embedding ratio was 79.5% and the drug loading was 24.1%. Cino-BSA-NP gave cinobufagin release of up to 53.5% within 3 h, followed by slower controlled release. Cino-BSA-NP inhibited growth of hepatocarcinoma cells in vitro to a similar extent as free cinobufagin, but with a much higher median lethal dose (LD50). Hepatic histomorphological changes indicated that hepatic damage was much less severe with Cino-BSA-NP than with free cinobufagin (2.19 mg/kg). The survival time of nude mice with orthotopic transplantation tumors treated with Cino-BSA-NP was prolonged significantly. The results confirm that Cino-BSA-NP renders cinobufagin completely dispersible in aqueous media, meeting the key requirements for intravenous injection, and show controlled release, thus significantly improving cinobufagin's antitumor activity while reducing its side effects.