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| Author(s): |
Paulo Roberto Del Valle
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD) |
| Defense date: | 2018-10-26 |
| Examining board members: |
Bryan Eric Strauss;
Luciana Nogueira de Sousa Andrade;
Ulysses Ribeiro Júnior;
Adriana Priscila Trapé
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| Advisor: | Bryan Eric Strauss |
| Abstract | |
Colorectal cancer is the third leading cause of cancer death and despite new molecular classifications, 30% to 40% of all patients will relapse after chemotherapy, pointing the need for new and innovative therapeutic strategies. The number of studies about viral vectors for gene therapy is growing, and previous data from our laboratory indicates that the combined delivery of Arf (a tumor suppressor gene and functional partner of p53) and interferon beta (IFNbeta, an immunomodulator cytokine), under a p53 responsive promoter, induced massive cell death and an important immunomodulatory effect. However, these results were only observed in murine models. Here we present an RGD-modified adenovirus whose transgene is under the control of a p53 responsive promoter (PG), used to transfer p53 (p53) and IFNbeta as a combined strategy to induce cell death in the presence of an immune modulator. Cell lines HCT116, HCT116 p53 -/- tolerated a MOI (multiplicity of infection) of 25, while a MOI of 100 was supported by HT29 (mutant p53 R273H). The p53-dependent PG promoter, as expected, provided reduced GFP expression levels in HCT116 p53 -/- and HT29, but the expression was increased in all cell lines when co-transduced with the p53 vector, but not with IFNbeta . In general, HCT116 and HCT116p53-/- were more sensitive to p53 gene transfer while HT29 was particularly affected by the combination of p53 + IFNtbeta. This trend was reflected in cell viability (growth curve, MTT), colony formation and accumulation of hypodiploid cells. Levels of cell death correlated with caspase 3/7 activity and staining with Annexin V. Immunogenic markers were also increased, especially for HT29 treated with INFbeta and p53/IFNbeta, as we detected exposure of calreticulin and release of ATP. Also, we observed increased expression of TP63, TP73 as well as p53 transcriptional targets, such as p21 and NOXA; SESTRIN was reduced in both HCTs but increased in HT29. Additionally, we tested the p53+IFNb combination in association with chemotherapeutics, revealing cooperation between gene transfer and doxorubicin or 5-FU even at the lowest doses tested. Ongoing studies include the evaluation of human dendritic cells exposed to tumor cells treated with the vectors for p53/IFNbeta. In conclusion, our combined gene transfer approach has potentiated the killing of colorectal cancer cell lines and may provide an immunomodulatory effect (AU) | |
| FAPESP's process: | 13/16074-3 - P53/ARF and interferon-beta pathways as targets for colorectal carcinoma gene therapy |
| Grantee: | Paulo Roberto Del Valle |
| Support Opportunities: | Scholarships in Brazil - Doctorate |