Transcriptional targeting of adenovirus vectors with the squamous cell carcinoma-specific antigen-2 promoter for selective apoptosis induction in lung cancer

Abstract

Squamous cell carcinoma antigens SCCA1 and SCCA2 are highly homologous serine proteinase inhibitors which have been widely utilized as serological markers for squamous cell cancers, but it has recently been demonstrated that only SCCA2 is truly specific for certain forms of lung cancer. Using a construct containing the 5 0 -flanking region of the SCCA2 gene between À460 and þ 0 bp and the luciferase reporter gene, SCCA2 promoter activity was detected in SCCA2-producing SCC cell lines (LK-2, LC-1), but not in SCCA2-nonproducing lung adenocarcinoma cell lines (A549, ABC-1, and RERF-LC-MS) or normal cells (WI-38, SAEC, and NHEKAdult). Infection with a recombinant adenovirus vector, Ad-SCCA2-DsRed, resulted in cell-specific expression of the SCCA2 promoter-driven DsRed marker gene only in LK-2 and LC-1 cells. The same strategy was used for SCCA2-driven expression of a proapoptotic gene, (KLAKLAK)2, which can cause mitochondrial disruption by triggering mitochondrial permeabilization and swelling, resulting in the release of cytochrome c and induction of apoptosis. Infection with Ad-SCCA2-KLAKLAK2 specifically reduced the growth of the two human lung SCC cell lines compared to the SCCA2 nonproducing cell lines both in vitro and in vivo, suggesting that the SCCA2 promoter had a tumor-specific effect. These results suggest that transduction of SCCA2 promotercontrolled suicide genes by adenoviral vectors can confer transcriptionally targeted cytotoxicity in SCCA2-producing lung SCC cells, and represents a novel strategy for gene transfer specifically targeted to SCC in the lung. Cancer Gene Therapy ( IntroductionLung carcinoma is the most common malignant neoplasm and represents the leading cause of cancer death in the developed world. 1 Among lung carcinomas, adenocarcinoma and squamous cell carcinoma (SCC) are the most frequently encountered forms. Despite the use of optimal chemotherapy and radiotherapy regimens, there has been little improvement in the prognosis of these cancer patients during the last decade. 2,3 This underscores the need to seek novel therapeutic modalities for lung cancer patients. One such approach is gene therapy by administration of vectors expressing cytotoxic genes; however, in order to maximize tumor-killing efficacy and minimize any potential adverse effects of this approach, it would be advantageous to employ a cancer-specific targeting strategy. For adenocarcinomas in general, transcriptional targeting by the use of cancer-specific promoters such as the carcinoembryonic antigen (CEA) promoter has been described previously. 4,5 However, little has been reported for SCC-specific regulation.The squamous cell carcinoma antigen (SCCA) was first reported by Kato et al. 6 in 1977 as a circulating tumor marker for SCC, particularly that of cervix, head and neck, esophagus, and lung. 7 Several studies have shown that increased serum SCCA levels are seen in SCC patients 8,9 and correlate with the extent of disease in patients with SCC, 10,11 although the protein itself is not detected in adenoca...

Antitumor potential of SLPI promoter controlled recombinant caspase-3 expression in laryngeal carcinoma

“…SLPI promoter selected as tissue-specific promoter in Hep-2 laryngeal carcinoma cells According to published literatures, three fragments of SLPI promoter (SLPIa, SLPIb and SLPIc ), 11 SCCA2 (À460 to 0) 5 and survivin (À1471 to À36) 12 genes were cloned by PCR and evaluated for their transcription activity. Dual-luciferase reporter assay showed that promoter SLPIb exhibited the highest transcription activity in Hep-2 cells among the promoters evaluated (Po0.05, one-way analysis of variance test) ( Table 2), and also exhibited specific transcription activity in Hep-2 cells when compared with that in either HUVEC or MG-63 cells, with approximately 37-fold and 17-fold differences, respectively (Figure 1), and was therefore selected as the tissue-specific promoter in Hep-2 laryngeal carcinoma cells in subsequent recombinant adenoviral vector construction.…”

Cancer targeted gene therapy of BikDD inhibits orthotopic lung cancer growth and improves long-term survival

“…One way to circumvent the non-specific delivery is to develop a strong cancer-specific expression vector. Most of the identified lung cancer-specific promoters exhibit a high level of lung cancer specificity but are still much weaker than the CMV promoter (Chen et al , 2004; Fukazawa et al , 2007; Oshikiri et al , 2006). To overcome this issue, we have established a specific promoter amplification system, called “VISA” (VP16-GAL4-WPRE integrated systemic amplifier) system (Xie et al , 2007) to significantly amplify the cancer-specific promoter activity to a comparable level to CMV in cancer cells while still retaining low promoter activity in normal tissues.…”

Conditionally replicating E1B-deleted adenovirus driven by the squamous cell carcinoma antigen 2 promoter for uterine cervical cancer therapy

“…SCCA2 promoter has been used to control proapoptotic gene expression by adenoviral vectors for selective induction of apoptosis in SCCA2-expressing lung cancer cells. 30 As the majority (up to 80%) of cervical cancers overexpress SCC, it is reasonable to use this modality for treating cervical cancer clinically. To our knowledge, this is the first report to use the SCCA2 promoter to transcriptionally drive the replication of an oncolytic adenovirus specifically in metastatic cervical tumors.…”

“…At nucleotide position À50, the A residue in SCCA2 is replaced by a G residue in SCCA1, and this appears to be responsible for the difference in transcriptional activities of the two promoters. 30 The complete SCCA2 gene locus has been cloned and its putative promoter region has been analyzed. The SCCA2 core promoter region exhibited a higher promoter activity in SCCA2-producing SKGIIIa than in nonproducing SK-OV-3 or K42 cells.…”