Anti-metastatic gene therapy utilizing subcutaneous inoculation of EC-SOD gene transduced autologous fibroblast suppressed lung metastasis of Meth-A cells and 3LL cells in mice

We have previously reported that superoxide stimulates the motility of tumor cells and the administration of Cu-Zn superoxide dismutase (SOD) significantly suppresses metastasis. However, ideally, anti-metastatic therapy should be long-lasting, systemically effective and have low toxicity. The half-life of Cu-Zn SOD in plasma is so short that it cannot provide long-lasting effects. Therefore, in this study we have developed a gene therapy in a mouse model utilizing extracellular SOD (EC-SOD), which is the most prevalent SOD isoenzyme in extracellular fluids. We retrovirally transfected fibroblasts (syngeneic) with the EC-SOD gene and established EC-SOD-secreting fibroblasts. Inoculation of EC-SOD-secreting fibroblasts suppressed both artificial and spontaneous metastatic lung nodules in mouse metastasis models. These data indicate the feasibility of anti-metastatic gene therapy utilizing the EC-SOD gene.

[Severe hemolysis and SIADH-like symptoms induced by vincristine in an ALL patient with liver cirrhosis]

An 11-year-old boy was diagnosed as having acute lymphoblastic leukemia (ALL, L1) in 1987 and underwent treatment with an ALL high-risk protocol (prednisolone, vincristine (VCR), daunorubicin, 1-asparaginase), which resulted in complete remission. In 1990 he developed chronic hepatitis C and received interferon therapy. In December 1994, ALL recurred, and the patient was treated with VCR. He subsequently developed severe hemolysis (Hb 12.5 g/dl-->6.8 g/dl) with increases of indirect bilirubin, AST, and LDH. Furthermore, symptoms resembling a syndrome of inappropriate secretion of ADH (SIADH) and DIC developed. Upon incubation of the patient's red blood cells with VCR in vitro, extreme deformity of the cells was observed. These findings suggested that splenomegaly, due to liver cirrhosis which had developed rapidly from chronic hepatitis C while the patient was in an immunosuppressed state induced by anticancer drugs, had trapped the deformed red blood cells and resulted in severe hemolysis. The patient died on the 165th day after admission due to liver failure.

Enhanced inhibition of experimental metastasis by the combination chemotherapy of Cu-Zn SOD and adriamycin

We previously reported that reactive oxygen species (ROS) enhance tumor cell metastasis, and by administration of recombinant human superoxide dismutase (rh SOD), an enzyme which scavenges O2- successfully reduced lung metastasis of mouse MethA sarcoma and Lewis lung carcinoma. These observations suggested that rh SOD suppressed tumor cell invasion by eliminating O2- the primary source of ROS. However, for the clinical application of the drug as an anti metastatic agent, rh SOD needs to be administered in combination with other cytotoxic agents, since SOD by itself has no cytotoxic activity. In this paper, we investigated the effectiveness of the combination chemotherapy of rh SOD and adriamycin (ADR), an anti-cancer agent against the experimental metastasis of highly metastatic clone, MH-02, which was derived from murine Meth A sarcoma. The present metastasis experiment clearly indicates that the administration of rh SOD enhances the antimetastatic effect of ADR. On the other hand, we found that the inhibition rate of metastasis exhibited by the combination chemotherapy of rh SOD and a certain dose (5 mg/ml) of ADR was inferior to that of rh SOD. This apparent paradoxical phenomenon was presumably explained by our finding that tumor cells themselves augment their invasive capacity and platelet aggregation, both of which are causative factors for metastasis formation, by generation of O2- when they were treated with ADR. Nevertheless, the combination chemotherapy of SOD with anticancer drugs such as ADR can be a practical anti-metastasis strategy.

Suppression of intracellular Cu-Zn SOD results in enhanced motility and metastasis of Meth A sarcoma cells

We have previously described an inverse relationship between Cu-Zn superoxide dismutase (SOD) activity and invasiveness of a clone of human tongue cancer cells. In these cells, suppression of Cu-Zn SOD activity by transfection with anti-sense cDNA enhanced motility in vitro. The present studies were undertaken to determine whether the inverse relationship between intracellular Cu-Zn SOD activity and motility is a general property of other tumor cells and whether this enzyme indeed defines in vivo metastatic potential. Murine Meth A sarcoma-derived ML-01 cells, which have low metastatic activity, were transfected with anti-sense Cu-Zn SOD cDNA. Two clones with very different SOD activities--ML-AS2, with the most suppressed, and ML-AS5, with the least suppressed activity-were analyzed for their motility and metastatic capability. Compared to the mocktransfectant ML-neo, the metastatic potential and motility of the ML-AS2 and ML-AS5 were increased 4.5- and 2.1-fold, respectively. Superoxide treatment enhanced the motility of the AS clones but not that of the ML-neo cells. Our results clearly show that there is an inverse relationship between the intracellular level of Cu-Zn SOD, cell motility and in vivo metastatic potential.

Superoxide dismutase in SAS human tongue carcinoma cell line is a factor defining invasiveness and cell motility

This article describes an apparent inverse relationship between cell motility and intracellular Cu-Zn superoxide dismutase (SOD) activity of two human squamous carcinoma-derived clones, SAS-H1 with high invasiveness and SAS-L1 with low invasiveness. Clone SAS-H1 exhibited significantly greater motility than SAS-L1 but had significantly lower levels of intracellular Cu-ZnSOD than SAS-L1 cells. We then transfected Cu-ZnSOD antisense cDNA into SAS-L1 to reduce the intracellular Cu-ZnSOD activity. Antisense cDNA transfected SAS-L-AS clones had lower Cu-ZnSOD activity than control vector-transfected SAS-L-Neo clones, and this was associated with increased motility. Invasiveness of SAS-H1 and SAS-L-AS1 was enhanced by superoxide treatment, while the invasiveness of SAS-L1 was unaffected. These findings indicate that intracellular SOD is involved in cell motility by virtue of its action in scavenging superoxide in the cells.