No abstract

Gene therapy with IL -12 has been shown to elicit potent systemic antitumor response in a variety of tumors. Although direct intratumoral injection is the most commonly used delivery route for gene therapy of solid tumors, the skeletal muscle has been shown to be an ideal tissue for gene delivery to produce systemic gene expression. We have previously demonstrated that electroporation delivery of a reporter gene to muscle enhances the transfection efficiency and the level of gene expression by two to three logs. We report here that intramuscular ( i.m. ) injection of as little as 10 g of the IL -12 DNA plasmid followed by electroporation prevents squamous cell carcinoma ( SCCVII ) tumor establishment in up to 40% of experimental animals and reduces the volume of established tumors by 75% compared to controls ( P < .05 ) . By comparison, there was no difference in tumor growth observed between IL -12 injection alone and injection of empty vector with or without electroporation. The induction of antitumor activity by i.m. electroporation delivery of the IL -12 gene is associated with an increase in IL -12 expression in muscle and serum. The level of IL -12 expression in muscle and serum was 1500 pg / tibialias muscle and 170 pg / mL serum, respectively, at day 6, after the gene was delivered by electroporation. In contrast, the level of IL -12 when the gene was injected without electroporation was hardly detectable after subtracting the background level of IL -12 detected in naõ Ève mice. The high level of IL -12 expression led to a 170 -fold induction of IFN -expression in serum at day 6 after i.m. electroporation delivery of IL -12 DNA plasmid, which was equal to 1450 pg / mL in the serum. The induction of antitumor activity by i.m. electroporation delivery of the IL -12 gene also correlates with increased CD8 + T -cell population in peripheral blood but not in spleen. Our findings suggest that i.m. delivery of IL -12 gene using electroporation is an effective method of inducing a systemic antitumor response against SCC. Cancer Gene Therapy ( 2001 ) 8, 151 ± 157

Identifying overexpressed genes in tumours is a critical step for tumour diagnosis, prognosis, and treatment. Using differential display polymerase chain reaction, sequence analysis, and gene Blast searches, we discovered that human prostaglandin F synthase (hPGFS) was upregulated in squamous cell carcinoma of the head and neck (SCCHN). Northern blot analysis indicated that up to a 16-fold increase in the level of hPGFS expression was detected in 40.5% (15 out of 37) of SCCHN primary tumours. The increased expression of hPGFS in SCCHN was primarily detected in SCC of larynx and hypopharynx (59%, Po0.05). Using the same primary tissue samples, increased levels of epidermal growth factor receptor (EGFR) expression were detected in only 32% of tumour tissues, suggesting hPGFS may have the potential to become a drug target or molecular marker for SCCHN. To determine if the increased level of hPGFS expression came from tumour cells, we determined the level of hPGFS expression in SCCHN tumour cell lines. A high level of hPGFS expression was detected in four out of five tumour SCCHN cell lines. To determine if upregulation of hPGFS is SCCHN-specific, hPGFS expression was analysed in 59 tumour cell lines derived from different types of tumours. The expression of hPGFS was increased from two-to 500-fold in a large portion of cell lines derived from lung (five out of nine), colon (five out of seven) as well as head and neck cancer (four out of five). These data link hPGFS expression to tumours located in the respiratory and digestive organs.