Oral adeno-associated virus-sTRAIL gene therapy suppresses human hepatocellular carcinoma growth in mice

Abstract

T umor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a type II transmembrane protein. Both membrane-bound and soluble forms of TRAIL selectively trigger apoptosis in tumor cells but not in most normal cells in vivo. 1,2 Many attempts have been made to study the therapeutic potential of TRAIL in cancer gene therapy in the last decade. It has been demonstrated recently that TRAIL or TRAIL-green fluorescent protein fusion gene expression mediated by adenoviral vectors results in apoptosis and bystander cell death in various human cancer cell lines in vitro 3 and in vivo. [4][5][6][7] However, an adenovirus vector might be harmful to hepatic cells through innate and cell-mediated immune responses. 8 Our previous report demonstrated that an adeno-associated virus (AAV) vector with the gene encoding the native extracellular domain of TRAIL 95-281 transferred in an orthotopic transplanted mouse model mimicking liver cancer metastasis resulted in significant suppression of growth and dissemination of the tumor and prolonged the survival of the treated mice without hepatoxicity. The soluble TRAIL was detectable both in mouse serum and within liver cells. 9 This experiment provided important evidence that the gene product could be secreted into the general circulation and function as a soluble cytokine efficiently acting on metastatic tumor cells. Moreover, the AAV's advantages of natural defectiveness, lack of pathogenicity and stability to temperature and pH extremes, and solvents have led to its potential use for an oral administration strategy. 10

Formyl peptide receptor-like 1–mediated endogenousTRAILgene expression with tumoricidal activity

“…It is reported that histidinetagged TRAIL has an altered protein conformation, reduced stability, decreased solubility, and liver toxicity; however, the soluble form of native TRAIL without tags is able to kill cancer cells with little or no evidence of toxicity to primary human hepatocytes in vitro (34). We previously proved that the recombinant soluble form of native TRAIL (rsTRAIL) produced in our laboratory was safe both in vivo and in vitro (14,17,26). In the present study, we observed that W peptide -enhanced endogenous TRAIL expression suppressed the growth of transplanted mouse liver tumor cells without toxicity to lung, liver, spleen, and kidney (data no shown).…”

Preclinical study of rAAV2-sTRAIL: pharmaceutical efficacy, biodistribution and safety in animals

“…More interestingly, we demonstrated that oral or intraperitoneal administration of rAAV-TRAIL resulted in an effective suppression of tumor growth without toxicity to normal hepatocytes since AAV is more resistant to acid and alkali, suggesting that oral administration of rAAV-TRAIL might be an important alternative route with practical significance for cancer gene therapy. 26 Yoo et al 34 also reported that intratumor injection of rAAV2 encoding soluble TRAIL to A549 lung adenocarcinoma mouse models (s.c.) led to 62% of reduced tumor size, and systemic delivery before implantation of A549 cells lowered the frequency of tumor occurrence to 43%, compared to 100% in untreated mice. These data strongly suggest that it is possible to increase AAV-mediated sTRAIL expression as a novel therapeutic strategy for cancer therapy.…”

“…We demonstrated that the rAAV2-sTRAIL virus infection significantly suppressed tumor growth and prolonged survival of mice implanted with human liver cancer or leukemia, while toxicity to normal tissue and cells was undetectable. 25,26 To further evaluate the safety and potential use in clinical trials for cancer, validation and safety test were carried out in this study. , and the expression of sTRAIL reached the peak at MOI of 2 × 10 5 vg per cell.…”

“…We previously established a recombinant AAV-mediated soluble TRAIL 95-281 gene expression for cancer therapy 25,26 and demonstrated that intraportal injection via the hepatic portal veins of rAAV-TRAIL 95-281 into the liver of an orthotopic-transplanted EL-4 mouse model mimicking liver cancer metastasis resulted in a significant suppression of tumor growth and prolonged survival, while normal hepatocyte toxicity is undetectable. Histological and biochemical analysis in tumor tissue and serum confirmed that TRAIL 95-281 in active trimeric form was stably expressed in relatively high level in hepatocytes and secreted into the serum.…”

Gene Therapy Strategies for Hepatocellular Carcinoma

“…Intratumoral administration of the TRAIL vector by electroporation significantly inhibited the growth not only of the HCC directly administered TRAIL vector, but also of distant subcutaneous HCC, with only small and transient liver damage being observed [57]. More interestingly, Ma et al recently demonstrated that adeno-associated virus (AAV) vector expressing the extracellular domain of TRAIL fused with a signal peptide could be administered orally or intraperitoneally, resulting in long-term and high level expression of soluble TRAIL in vivo, effective regression of the subcutaneously implanted tumors, and lack of toxicity to normal hepatocytes [58]. It will be interesting to further test whether such systemic administration of TRAIL exerts similar tumoricidal effects on orthotopic liver tumors.…”