Liposome-mediated gene transfer of K1-5 suppresses tumor development and improves the prognosis of hepatocellular carcinoma in mice

Advances in Nanoliposomes for the Diagnosis and Treatment of Liver Cancer

The mortality rate of liver cancer is gradually increasing worldwide due to the increasing risk factors such as fatty liver, diabetes, and alcoholic cirrhosis. The diagnostic methods of liver cancer include ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI), among others. The treatment of liver cancer includes surgical resection, transplantation, ablation, and chemoembolization; however, treatment still faces multiple challenges due to its insidious development, high rate of recurrence after surgical resection, and high failure rate of transplantation. The emergence of liposomes has provided new insights into the treatment of liver cancer. Due to their excellent carrier properties and maneuverability, liposomes can be used to perform a variety of functions such as aiding in imaging diagnoses, combinatorial therapies, and integrating disease diagnosis and treatment. In this paper, we further discuss such advantages.

Development of Recombinant Adeno-Associated Virus Serotype 2/8 Carrying Kringle Domains of Human Plasminogen for Sustained Expression and Cancer Therapy

Angiostatin and other plasminogen derivatives exhibit antitumor activities directly or indirectly, have demonstrated promising anticancer effects in preclinical studies, but have mostly failed in clinical trials partly due to their short serum half-lives. Our previous studies demonstrated that recombinant human plasminogen kringle 1-5 (K1-5) has superior antitumor activity compared with angiostatin. In addition, optimization of recombinant K1-5 with three amino acid substitutions enhances its antitumor effect. The current study was thus undertaken to evaluate prolonged expression of optimized K1-5 as cancer gene therapy. The recombinant adeno-associated virus (AAV) vector was used to express a secreted form of the optimized K1-5 (AAV-sK15tm) to improve its pharmacokinetic profile, which was considered to be the hurdle in angiostatin treatment of cancer. We successfully generated high-titer recombinant AAV vectors and observed sustained transgene expression for 567 days after a single injection of virus. The treated animals did not display any visible signs of abnormalities and showed normal serum biochemistry. The therapeutic potential of this treatment modality was demonstrated by both a strong inhibition of lung metastasis in the mouse B16F10 melanoma model and significant growth retardation of Lewis lung carcinoma xenografts in C57BL/6N mice as well as human A2058 melanoma xenografts in NOD/SCID (nonobese diabetic/severe combined immunodeficient) mice. Taken together, our results suggested that AAV-sK15tm produced long-term suppressive effects on cancer growth in vivo and should warrant serious consideration for clinical development.

Fiber-modified adenovirus can mediate human adipose tissue-derived mesenchymal stem cell-based anti-angiogenic gene therapy

A fiber-modified adenovirus (rAd5F11B), loaded with the Kringle1-5 gene (rAd-K1-5) was used to infect human adipose tissue-derived mesenchymal stem cells (HAMSCs). At a multiplicity of infection of 20, the transfection efficiency in HAMSCs was 90% and the cell expansion and differentiation of infected HAMSCs were not significantly suppressed. HAMSCs infected with rAd-K1-5 expressed the exogenous Kringle1-5 protein, an angiogenic inhibitor, and conditioned media from HAMSCs expressing the Kringle1-5 protein blocked VEGF-induced neovascularization both in vitro and in vivo. rAd5F11B may therefore be a promising gene transfer vector in HAMSCs-based anti-angiogenic gene therapy because of its low toxicity and high transfection efficiency.

Adeno-associated virus-mediated delivery of kringle 5 of human plasminogen inhibits orthotopic growth of ovarian cancer

Kringle 5 (K5) of human plasminogen is a potent angiogenesis inhibitor. In this study, we investigated the effects of recombinant adeno-associated virus (AAV)-mediated delivery of K5 in mouse models of human ovarian cancer. A single intramuscular injection of AAV-K5 resulted in sustained expression of K5 reaching a maximum serum level of 800 ng ml(-1). Gene therapy inhibited both vascular endothelial growth factor (VEGF)-induced and tumor cell-induced angiogenesis in matrigel plug assays. Furthermore, a single injection of AAV-K5 significantly inhibited both subcutaneous and intraperitoneal growth of human ovarian cancer cells. Immunofluorescence studies of residual tumors surgically resected from the treated animals showed reduced tumor burden, which correlated with the inhibition of tumor neovascularization. In addition, AAV-K5 gene therapy differentially affected the nascent vessels more than mature vasculature and induced apoptotic death of tumor cells. These data show that AAV-K5 can be effectively used to inhibit ovarian cancer.