ABSTRACT
Objective To construct a prostate cancer specific oncolytic adenovirus armed with a fusion protein gene , PSA-IZ-CD40L, and to evaluate its oncolytic efficiency and immune activation ability in vitro.Methods Prostate Specific Antigen (PSA) gene, CD40L-N and CD40L-C genes were obtained from cDNA of LNCaP cells and Jurkat cells using poly-merase chain reaction (PCR) or nested-PCR, respectively.PSA,Linker,CD40L-N and CD40L-C were linked sequentially to generate fusion protein gene PSA-IZ-CD40L (PL) by overlapping PCR.Then, prostate specific oncolytic adenovirus PL-carrying gene, Ad-PL-PPT-E1A,was constructed using the oncolytic adenovirus system , which was based on Adeasy sys-tem.PC3M cells were infected by Ad-PL-PPT-E1A at serial multiplicity of infection (MOI), and the apoptosis was detec-ted by flow cytometry at several time points post-infection.For immune activation detection , PC3M cells were infected with Ad-PL-PPT-E1A at a MOI of 50, and the cell lysate was collected at 48 h post-infection.Peripheral blood mononuclear cells derived (PBMCs) from healthy donors were stimulated by the lysate from PC 3M cells or Ad-PL-PPT-E1A infected PC3M cells before proliferation was assayed using cell counting kit-8 (CCK8).Results Fusion protein gene, PSA-IZ-CD40L, was successfully constructed and cloned into the prostate cancer specific adenovirus to generate Ad -PL-PPT-PL. The expression of E1A and PL protein could be detected by reverse transcription PCR and Western-blotting.Cytopathic effect was observed in PC3M cells infected with Ad-PL-PPT-E1A.Furthermore, the apoptosis rate reached 70.67% ± 2.98%at 48 h post-infection with 200 MOI Ad-PL-PPT-E1A.Compared with the lysate of PC3M cells, that from Ad-PL-PPT-E1A infected cells could promote the proliferation of PBMCs .Conclusion We have constructed a prostate cancer spe-cific oncolytic adenovirus armed can fusion protein gene PL , Ad-PL-PPT-E1A, which could kill PC3M cells effectively and enhance the proliferation of PBMCs in vitro.
ABSTRACT
PURPOSE: Gastric cancer has the highest incidence rate among cancers in Asia. The advanced type of signet ring cell carcinoma has poor prognosis compared to other types of gastric cancer. The immuno-gene therapy with cytokine-based tumor vaccines has not yet been investigated for gastric cancer. The granulocyte macrophage colony-stimulating factor (GM-CSF)-based tumor vaccine has been demonstrated as the most potent stimulator for specific and long-lasting systemic tumor immunity. MATERIALS AND METHODS: In the present study, KATO III cells, the human signet ring cell gastric carcinoma cell line, were genetically modified by the transduction with the human GM-CSF cDNA or the modified hGM-CSF in replication-deficient retroviruses. The genomic integrations and mRNA expressions of the transgenes were determined by Southern and Northern blot analyses. RESULTS: Wild type (wt) or modified hGM-CSF was integrated into the genome of KATO III cells. The modified hGM-CSF mRNA was more stable than that of wt. The KATO III cells with the modified hGM-CSF produced higher level of hGM-CSF (12.4-19 ng/10(6)cells/48hrs) than that with wt hGM-CSF, when determined by enzyme-linked immunosorbent assay (ELISA). The secreted recombinant hGM-CSF could support the proliferation of the GM-CSF-dependent cell line, indicating that the hGM-CSF secreted by the transduced KATO III cells has biological activities. Irradiated, transduced KATO III cells continued to secret hGM-CSF without proliferation. CONCLUSION: Our results suggest that GM-CSF secreting KATO III cells could be tested for the treatment of gastric cancer as an allogeneic tumor vaccine as a part of immunotherapeutic treatment.