http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Design of novel gene transfection vectors for targeted gene therapy
xiii, 178 leaves : illustrations (some color) ; 28 cm.
ABSTRACT: One of the main obstacles of cancer therapy is treatment of tumors resistant to chemotherapeutic agents. We hypothesized that cancer specific delivery of wild-type (wt) p53 may increase the sensitivity of wt-p53 and mutant-type (mt) p53 expressing cells to doxorubicin. As a first step to realize our goal, two cancer cell specific ligands (ornithine, a polyamine precursor; and SV119, a sigma-2 receptor ligand) were conjugated to the surface of PAMAMG4 dendrimers, separately. Stability of dendriplexes formed using surface modified dendrimers and plasmid DNA was assessed against nuclease (DNase I). Transfection efficiency of the dendriplexes was investigated in normal and cancer cells. Cancer cell specific expression by heparanase (HPR) promoter driven pGFP-p53, constructed by replacing CMV promoter, was studied in breast cancer cells. Effect of wt-P53 treatment on doxorubicin cytotoxicity in MCF 12A (normal breast cells expressing wt-p53) and cancer cells (MCF 7: expressing wt-p53, MDA-MB-231: expressing mt-p53 and NCI/ADR-RES: expressing mt-p53 and doxorubicin resistant) cells was assessed by MTT assay. ¹H NMR and MALDI-TOF spectral analysis showed that 60 molecules of ornitine (PAMAMG4-ORN60) and 7 molecules of SV119 (PAMAMG4-SV119) were conjugated to a PAMAMG4 dendrimer, separately. Transfection efficiency of PAMAMG4-ORN60 was higher in PAT efficient NCI H157G (63.07 [plus/minus] 6.8%) but low in PAT deficient NCI H157R (31.66 [plus/minus] 3.95%) cancercells [sic]. Transfection efficiency of PAMAMG4-SV119 was significantly higher in cancer cells than normal cells (P<0.0001). HPR promoter activity for GFP-p53 expression was 10-20 folds less than CMV promoter. Dendriplexes were non-toxic at concentrations [greater than or equal to] 50 [mu]g/mL. PAMAMG4-ORN60 showed significantly greater specificity (P< 0.001) towards cancer cells than PAMAMG4-SV119. Exogenous p53 expression lasted for 4 days and wt-p53 treatment increased the cytotoxicity of doxorubicin to MCF-7, MDA-MB-231 and NCI/ADR-RES cells significantly (P< 0.005). It can be concluded that a combination of wt-p53 and doxorubicin may be an efficient module to treat doxorubicin-resistant cancer.
"Submitted to the School of Graduate Studies of the Texas A&M University System Health Science Center in partial fulfillment of the requirements for the degree of Doctor of Philosophy May 2012."
Approved as to style and content by: Srinath Palakurthi, Lacy Daniels, Cynthia J. Meininger, Steve A. Maxwell, Van G. Wilson.
Ph. D. Texas A&M University System Health Science Center 2012.