| 1. |
- Cheng, Wing-Shing, et al.
(författare)
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An oncolytic conditionally replicating adenovirus for hormone-dependent and hormone-independent prostate cancer
- 2006
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Ingår i: Cancer Gene Therapy. - 0929-1903 .- 1476-5500. ; 13:1, s. 13-20
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Tidskriftsartikel (refereegranskat)abstract
- The use of conditionally replicating adenoviruses offers an attractive complementary treatment strategy for localized prostate cancer. We have produced a replicating adenovirus, Ad[I/PPT-E1A], where E1A gene expression is controlled by a recombinant regulatory sequence designated PPT. The PPT sequence comprises a PSA enhancer, a PSMA enhancer and a T-cell receptor gamma-chain alternate reading frame protein promoter, and it is shielded from transcriptional interference from adenoviral backbone sequences by an H19 insulator. Ad[I/PPT-E1A] yields prostate-specific E1A protein expression, viral replication and cytolysis in vitro. Furthermore, Ad[I/PPT-E1A] considerably regresses the growth of subcutaneous LNCaP prostate cancer tumors in nude mice. Importantly, the viral replication and cytolytic effect of Ad[I/PPT-E1A] are independent of the testosterone levels in the prostate cancer cells. This may be beneficial in a clinical setting since many prostate cancer patients are treated with androgen withdrawal. In conclusion, Ad[I/PPT-E1A] may prove to be useful in the treatment of localized prostate cancer.
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| 2. |
- Cheng, Wing-Shing, 1974-
(författare)
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TARP Promoter-Based Prostate Cancer Gene Therapy : From Development to Application
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Prostate cancer is one leading cause of cancer-related death among men in Western countries. The standard therapies for localized prostate cancer include radical prostatectomy and radiation therapy. Such measures are relatively effective in the short term, but many patients ultimately relapse. These patients may benefit from a combination of standard therapy and oncolytic virus therapy. My work aimed to develop viruses for this purpose.TARP is a protein that in males is specifically expressed in prostate epithelial and cancer cells. In my thesis, I characterized the TARP promoter and showed that TARP expression is regulated at the transcriptional level by testosterone through binding of the androgen receptor in the proximal TARP promoter. I further developed TARP promoter-based regulatory sequences for prostate-specific gene expression. A sequence comprising a PSA enhancer, a PSMA enhancer and the TARP promoter was constructed and designated PPT. An adenoviral vector containing the PPT sequence shielded from transcriptional interference by an H19 insulator showed high prostate-specific transcriptional activity in human cells both in the presence and absence of testosterone. However, in experimental murine prostate cancer the PPT sequence is not active. Therefore, a two-step transcriptional amplification (TSTA) system was used together with the PPT sequence to develop an adenovirus that confers prostate-specific transgene expression also in murine cells.I constructed a conditionally replicating adenovirus where the E1A gene expression is controlled by an H19 insulator-shielded PPT regulatory sequence, Ad[I/PPT-E1A]. This virus exhibited absolute prostate specificity in terms of E1A expression, viral replication and cytolysis in vitro and in vivo. Importantly, our virus is active both in the presence and absence of testosterone, which may prove beneficial for patients treated by hormonal withdrawal. Hopefully, my work will improve existing gene therapy strategies for prostate cancer and in the long term improve the prognosis for patients with prostate cancer.
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| 3. |
- Dzojic, Helena, et al.
(författare)
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Two-step amplification of the human PPT sequence provides specific gene expression in an immunocompetent murine prostate cancer model
- 2007
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Ingår i: Cancer Gene Therapy. - : Springer Science and Business Media LLC. - 0929-1903 .- 1476-5500. ; 14:3, s. 233-240
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Tidskriftsartikel (refereegranskat)abstract
- The recombinant prostate-specific PPT sequence comprises a prostate-specific antigen enhancer, a PSMA enhancer and a TARP promoter. It is transcriptionally active in human prostate cancer cells both in the presence and absence of testosterone. However, in experimental murine prostate cancer, it has no detectable transcriptional activity. Herein, we describe that the PPT sequence in combination with a two-step transcriptional amplification (TSTA) system becomes active also in murine prostate cancer cells. An adenovirus with TSTA-amplified PPT-controlled expression of the luciferase reporter gene, Ad[PPT/TSTA-Luc], has up to 100-fold higher prostate-specific transcriptional activity than a non-amplified PPT-based adenovirus, Ad[PPT-Luc], in human cells. In addition, Ad[PPT/TSTA-Luc] confers prostate-specific transgene expression in murine cells, with an activity that is approximately 23% of Ad[CMV-Luc] in the transgenic adenocarcinoma of the mouse prostate (TRAMP)-C2 cells. Moreover, to visualize luciferase expression in living mice a charge-coupled device camera was used. Ad[PPT/TSTA-Luc] yielded approximately 30-fold higher transgene expression than Ad[PPT-Luc] in LNCaP tumor xenografts. Importantly, Ad[PPT/TSTA-Luc] also showed activity in murine TRAMP-C2 tumors, whereas Ad[PPT-Luc] activity was undetectable. These results highlight that the recombinant PPT sequence is active in murine prostate cancer cells when augmented by a TSTA system. This finding opens up for preclinical studies with prostate-specific therapeutic gene expression in immunocompetent mice.
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