Salmonella-mediated blood‒brain barrier penetration, tumor homing and tumor microenvironment regulation for enhanced chemo/bacterial glioma therapy

Chemotherapy is an important adjuvant treatment of glioma, while the efficacy is far from satisfactory, due not only to the biological barriers of blood‒brain barrier (BBB) and blood‒tumor barrier (BTB) but also to the intrinsic resistance of glioma cells via multiple survival mechanisms such as up-regulation of P-glycoprotein (P-gp). To address these limitations, we report a bacteria-based drug delivery strategy for BBB/BTB transportation, glioma targeting, and chemo-sensitization. Bacteria selectively colonized into hypoxic tumor region and modulated tumor microenvironment, including macrophages repolarization and neutrophils infiltration. Specifically, tumor migration of neutrophils was employed as hitchhiking delivery of doxorubicin (DOX)-loaded bacterial outer membrane vesicles (OMVs/DOX). By virtue of the surface pathogen-associated molecular patterns derived from native bacteria, OMVs/DOX could be selectively recognized by neutrophils, thus facilitating glioma targeted delivery of drug with significantly enhanced tumor accumulation by 18-fold as compared to the classical passive targeting effect. Moreover, the P-gp expression on tumor cells was silenced by bacteria type III secretion effector to sensitize the efficacy of DOX, resulting in complete tumor eradication with 100% survival of all treated mice. In addition, the colonized bacteria were finally cleared by anti-bacterial activity of DOX to minimize the potential infection risk, and cardiotoxicity of DOX was also avoided, achieving excellent compatibility. This work provides an efficient trans-BBB/BTB drug delivery strategy via cell hitchhiking for enhanced glioma therapy.

Restoration of Wild - type p53 Induces Chemo-sensitization in the Gastric Cancer Cell Line with Mutant p53 / 대한암학회지

PURPOSE: It has been theorized that p53 may be involved in the sensitivity to chemotherapeutic agents. We evaluated the chemosensitivity of wild p53 after transduction into gastric cancer cell lines with mutant p53. MATERIALS AND METHODS: YCC-3(parent cell line with mutant p53), YCC-3v(parent cell line transduced with vector alone) and YCC-3C3(clone with wild p53) cell lines were used in this study. p53 protein expression was measured by ELISA assay. Tumorigenicity and drug sensitivity were evaluated by soft agar and proliferation assay, respectively. Cell cycle analysis was performed by flowcytometry. Telomerase activity was measured by TRAP assay and terminal restriction fragment(TRF) length was measured after Southern blot analysis. RESULTS: Even though p53 production from the YCC-3C3 cell line was three times higher than those of YCC-3 and YCC-3v cell lines, the cell cycle was the same in these three cell lines. In the YCC-3C3 cell line, drug sensitivity to etoposide and cisplatin was increased when we compared it to those of the YCC-3v cell line(etoposide, 50% versus 83%; cisplatin, 67% versus 83%). However, there was no chemo-sensitization effect with vincristine, vinblastine and carboplatin. After exposure to cisplatin, a G0/G1 check-point effect was found in the YCC-3C3 cell line, but not in the YCC-3v cell line. No differences were found in telomerase activity, TRFs length or DNA fragmentation between the YCC-3v and YCC-3C3 cell lines after cisplatin treatment. CONCLUSION: Wild-type p53 gene transduction in the gastric cancer cell line induced sensitization to the cytotoxicity of etoposide and cisplatin. This suggests the possible application of combined chemo-gene therapy with an EP regimen and wild-type p53 in gastric cancer patients with p53 mutation.

Anti-tumor Effects of Growth Factor Inhibitors and Anti-metastatic Agents in Human Gastric Cancer Cell Lines / 대한암학회지

PURPOSE: For tumor growth, invasion and metastasis, a cascade of linked sequential biological events is essential; overproduction of growth factors, activation of proteolytic enzymes, induction of tumor angiogenesis, and enhanced tumor cell motility and attachment. We tried to test whether the biological therapy against the biological targets can modulate the specific biological characteristics, and furthermore increased anti-tumor effects can be induced when the biological therapy and cytotoxic chemotherapy were combined. MATERIALS AND METHODS: YCC-1, 2, 3, 7, and AGS human gastric cancer cell lines were used in these studies. Pentosan polysulfate (PPS) as a heparin-binding growth factor (HBGF) inhibitor, Tranexamic acid as a plasmin inhibitor, Adriamycin as a chemotherapeutic agent, were selected. The methods were Northern blot analysis for the detection of Midkine (MK) expression, soft agar assay for autocrine tumorigenicity. The expression of uPA, PAI-1 was determined by ELISA, while the MMPs activities were evaluated by zymography. The effects of each drug on tumorigenicity and tumor cell proliferation were evaluated by soft agar assay and cell proliferation assay, respectively. RESULTS: YCC-3, 7, AGS cell lines expressed MK mRNA, whereas YCC-1, 2 did not. YCC-2 cell line showed increased expression of uPA and MMP activities. Only MK expressing YCC-3 and 7 cell lines showed the tumorigenicity. PPS suppressed the colony forming activities as much as Adriamycin did (PPS; 8~24%, Adriamycin; 12~40%), but it showed only cytostatic effects in cell proliferation assay (PPS; 60~103%, Adriamycin; 22~97%). When PPS was combined with Adriamycin on the Adriamycin resistant, MK expressing YCC-7 cell line, the growth inhibition rate increased up to 84%, while that of PPS or Adriamycin single treatment was 40%, 22%, respectively (p=0.001). CONCLUSION: The modulation of specific biological targets can induce the anti-tumor effects. This suggests the possible clinical application of biological therapy in gastric cancer.