Background Improvement of transduction and augmentation of cytotoxicity are necessary for adenoviruses (Ad)-mediated gene therapy for malignancy. in cell death anti-tumor effects in vivo and production of viral progenies were also investigated. Results Replication-competent AdF35 in general achieved greater cytotoxic effects to esophageal carcinoma cells than the corresponding replication-competent Ad5. Infection with the AdF35 induced cleavages of caspases and increased sub-G1 fractions but did not activate the autophagy pathway. Transduction with Ad5/p53 in combination with the replication-competent AdF35 further enhanced the Telotristat Myh11 Etiprate cytotoxicity in a synergistic manner. We also exhibited Telotristat Etiprate the combinatory effects in an animal model. Transduction with Ad5/p53 however suppressed production of replication-competent AdF35 progenies but the combination augmented Ad5/p53-mediated p53 expression levels and the downstream pathways. Conclusions Combination of replication-competent AdF35 and Ad5/p53 achieved synergistic cytotoxicity due to enhanced p53-mediated apoptotic pathways. Electronic supplementary material The online version of this article (doi:10.1186/s12885-015-1482-8) contains supplementary material which is available to authorized users. ((genes were activated by the MK regulatory region produced anti-tumor effects on hepatocellular carcinoma . Ad5 expressing the wild-type gene (Ad5/p53) have been clinically in use for cancer treatments and produced combinatory anti-tumor effects with chemotherapeutic brokers [15 16 We also exhibited that Ad5/p53 produced cytotoxic effects on human esophageal carcinoma and that the Telotristat Etiprate cytotoxicity was linked with CAR expression levels . These results raise a possibility that enhanced p53 expression in combination with replication-competent Ad augments the anti-tumor effects. In this study we examined cytotoxicity of replication-competent AdF35 powered by regulatory region of MK (AdF35-MK) or Sur (AdF35-Sur) on a panel of human esophageal carcinoma cells and examined a possible combinatory effect of Ad5/p53 and the AdF35. Methods Cells and mice Human esophageal squamous cell carcinoma lines TE-1 TE-2 TE-10 TE-11 YES-2 YES-4 YES-5 YES-6 and T.Tn cells from Cell Resource Center for Biomedical Research Tohoku University or college Sendai Japan were cultured with RPMI 1640 medium supplemented with 10?% fetal calf serum. The genotype of respective tumors is shown in Table?1. Human embryonic kidney (HEK) 293 cells and human lung carcinoma A549 cells from American Type Culture Collection (Manassas VA USA) were cultured with DMEM medium supplemented with 10?% fetal calf serum. BALB/c nu/nu mice (5-6 week-old females) were purchased from Japan SLC (Hamamatsu Japan). Table 1 Infectivity of Ad5 and AdF35 to esophageal carcinoma cells and CAR expression levels Ad preparation Replication-incompetent Ad5 DNA bearing the wild-type (Ad5/GFP) and the gene (Ad5/LacZ) were constructed by ligation of transgene-harboring pShuttle 2 (Takara Tokyo Japan) and Adeno-X vector (Takara). Ad35 DNA bearing the above transgenes (AdF35/GFP AdF35/LacZ) was produced with Adeno-X vector substituted with the Ad35 fiber-knob region. The fiber-knob altered Adeno-X DNA was created by replacing a fragment made up of the Ad35 fiber-knob region (Avior therapeutics Seattle WA) (“type”:”entrez-nucleotide” attrs :”text”:”AY271307″ term_id :”32967018″ term_text :”AY271307″AY271307 at 30 827 609 with that of Ad5-derived region. The replication-incompetent Ad used the cytomegalovirus promoter to activate the transgene. Replication-competent Ad DNA of which the genes were activated by a transcriptional regulatory region of the or the gene (Ad5/MK AdF35/MK Ad5/Sur AdF35/Sur) were prepared with the regulatory sequences-harboring pShuttle 2 and Adeno-X vector or the fiber-knob replaced Adeno-X vector. The Ad DNA was transfected into HEK293 cells and the Ad were purified with an Adeno-X purification kit (Takara). Infectivity of Ad and receptor expression Cells were infected with Ad5/GFP or AdF35/GFP at 30 multiplicity of contamination (MOI) for 30?min and were washed Telotristat Etiprate to remove the Ad. They were.