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A probasin promoter, conditionally replicating adenovirus that expresses the sodium iodide symporter (NIS) for radiovirotherapy of prostate cancer.

Trujillo MA, Oneal MJ, McDonough S, Qin R, Morris JC - Gene Ther. (2010)

Bottom Line: Conversely, the prostate cancer cell line PC-3 (androgen receptor negative) and the pancreatic cancer cell line Panc-1 were refractory to the viral cytopathic effect and did not support viral replication.Radioiodine uptake was readily measurable in LnCaP cells infected with Ad5PB_RSV-NIS 24 h post-infection, confirming NIS expression.Administration of therapeutic ¹³¹I after virus injection significantly increased survival probability in mice carrying xenografted LnCaP tumors compared with virotherapy alone.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine, Division of Endocrinology, Diabetes, Metabolism, Nutrition, Mayo Clinic, Rochester, MN 55905, USA.

ABSTRACT
The sodium iodide symporter (NIS) directs the uptake and concentration of iodide in thyroid cells. We have extended the use of NIS-mediated radioiodine therapy to other types of cancer, we transferred and expressed the NIS gene into prostate, colon and breast cancer cells using adenoviral vectors. To improve vector efficiency we have developed a conditionally replicating adenovirus (CRAd) in which the E1a gene is driven by the prostate-specific promoter, Probasin and the cassette RSV promoter human NIScDNA-bGH polyA replaces the E3 region (CRAd Ad5PB_RSV-NIS). In vitro infection of the prostate cancer cell line LnCaP resulted in virus replication, cytolysis and release of infective viral particles. Conversely, the prostate cancer cell line PC-3 (androgen receptor negative) and the pancreatic cancer cell line Panc-1 were refractory to the viral cytopathic effect and did not support viral replication. Radioiodine uptake was readily measurable in LnCaP cells infected with Ad5PB_RSV-NIS 24 h post-infection, confirming NIS expression. In vivo, LnCaP tumor xenografts in nude-mice injected intratumorally with Ad5PB_RSV_NIS CRAd expressed NIS actively as evidenced by ⁹⁹Tc uptake and imaging. Administration of therapeutic ¹³¹I after virus injection significantly increased survival probability in mice carrying xenografted LnCaP tumors compared with virotherapy alone. These data indicate that Ad5PB_RSV_NIS replication is stringently restricted to androgen-positive prostate cancer cells and results in effective NIS expression and uptake of radioiodine. This construct may allow multimodal therapy, combining cytolytic virotherapy with radioiodine treatment, to be developed as a novel treatment for prostate cancer.

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Titration of viral genome copies in xenografted tumorsTwo LnCaP and two Panc-1 xenografted tumors were infected with Ad5PB_RSV-NIS at 1011 vp. Non-infected tumors were used as controls. On day ten the animals were sacrificed and the tumors removed. Viral genome copies were titred by QPCR using three different longitudinal sections (left, center, and right) for each tumor
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Figure 5: Titration of viral genome copies in xenografted tumorsTwo LnCaP and two Panc-1 xenografted tumors were infected with Ad5PB_RSV-NIS at 1011 vp. Non-infected tumors were used as controls. On day ten the animals were sacrificed and the tumors removed. Viral genome copies were titred by QPCR using three different longitudinal sections (left, center, and right) for each tumor

Mentions: Next, we tested Ad5PB_RSV-NIS ability to direct NIS expression in vivo by imaging. When tumors reached 200 mm3 a single Ad5PB_RSV-NIS dose of 1011 vp of was administered intratumorally. Twenty-four hours later, an intraperitoneal dose of 0.5μCi of 99Tc was administered. NIS-mediated 99Tc uptake was detected with a noninvasive micro SPECT-CT imaging system. Figure 5A shows a classical time lapse uptake in LnCaP and Panc-1 xenografted tumors. One hour after delivery of the radiotracer, uptake can be detected in all animals receiving a 99Tc dose over the stomach due to native expression of NIS in the gastric mucosa, even in the absence of viral injection 5,28. The thyroid also concentrates 99Tc representing the major NIS expressing organ. Finally the bladder, is also imaged as a result of clearance of the radioisotope in the urine. However, due to their position in the plane of the image, these organs are not seen in all images. Very minimal 99Tc uptake was detected in the Panc-1 tumor at any time point after viral administration (Figure 4A). On the other hand, figure 4A reveals strong 99Tc uptake by the LnCaP tumor that has been injected with the Ad5PB_RSV-NIS CRAd 24 hours post-infection. Quantitation of the image yielded 99Tc uptake in infected tumors of more than 12% of the injected dose. These data indicate specific NIS-mediated 99Tc uptake in the permissive tumor.


A probasin promoter, conditionally replicating adenovirus that expresses the sodium iodide symporter (NIS) for radiovirotherapy of prostate cancer.

Trujillo MA, Oneal MJ, McDonough S, Qin R, Morris JC - Gene Ther. (2010)

Titration of viral genome copies in xenografted tumorsTwo LnCaP and two Panc-1 xenografted tumors were infected with Ad5PB_RSV-NIS at 1011 vp. Non-infected tumors were used as controls. On day ten the animals were sacrificed and the tumors removed. Viral genome copies were titred by QPCR using three different longitudinal sections (left, center, and right) for each tumor
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC2914818&req=5

Figure 5: Titration of viral genome copies in xenografted tumorsTwo LnCaP and two Panc-1 xenografted tumors were infected with Ad5PB_RSV-NIS at 1011 vp. Non-infected tumors were used as controls. On day ten the animals were sacrificed and the tumors removed. Viral genome copies were titred by QPCR using three different longitudinal sections (left, center, and right) for each tumor
Mentions: Next, we tested Ad5PB_RSV-NIS ability to direct NIS expression in vivo by imaging. When tumors reached 200 mm3 a single Ad5PB_RSV-NIS dose of 1011 vp of was administered intratumorally. Twenty-four hours later, an intraperitoneal dose of 0.5μCi of 99Tc was administered. NIS-mediated 99Tc uptake was detected with a noninvasive micro SPECT-CT imaging system. Figure 5A shows a classical time lapse uptake in LnCaP and Panc-1 xenografted tumors. One hour after delivery of the radiotracer, uptake can be detected in all animals receiving a 99Tc dose over the stomach due to native expression of NIS in the gastric mucosa, even in the absence of viral injection 5,28. The thyroid also concentrates 99Tc representing the major NIS expressing organ. Finally the bladder, is also imaged as a result of clearance of the radioisotope in the urine. However, due to their position in the plane of the image, these organs are not seen in all images. Very minimal 99Tc uptake was detected in the Panc-1 tumor at any time point after viral administration (Figure 4A). On the other hand, figure 4A reveals strong 99Tc uptake by the LnCaP tumor that has been injected with the Ad5PB_RSV-NIS CRAd 24 hours post-infection. Quantitation of the image yielded 99Tc uptake in infected tumors of more than 12% of the injected dose. These data indicate specific NIS-mediated 99Tc uptake in the permissive tumor.

Bottom Line: Conversely, the prostate cancer cell line PC-3 (androgen receptor negative) and the pancreatic cancer cell line Panc-1 were refractory to the viral cytopathic effect and did not support viral replication.Radioiodine uptake was readily measurable in LnCaP cells infected with Ad5PB_RSV-NIS 24 h post-infection, confirming NIS expression.Administration of therapeutic ¹³¹I after virus injection significantly increased survival probability in mice carrying xenografted LnCaP tumors compared with virotherapy alone.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine, Division of Endocrinology, Diabetes, Metabolism, Nutrition, Mayo Clinic, Rochester, MN 55905, USA.

ABSTRACT
The sodium iodide symporter (NIS) directs the uptake and concentration of iodide in thyroid cells. We have extended the use of NIS-mediated radioiodine therapy to other types of cancer, we transferred and expressed the NIS gene into prostate, colon and breast cancer cells using adenoviral vectors. To improve vector efficiency we have developed a conditionally replicating adenovirus (CRAd) in which the E1a gene is driven by the prostate-specific promoter, Probasin and the cassette RSV promoter human NIScDNA-bGH polyA replaces the E3 region (CRAd Ad5PB_RSV-NIS). In vitro infection of the prostate cancer cell line LnCaP resulted in virus replication, cytolysis and release of infective viral particles. Conversely, the prostate cancer cell line PC-3 (androgen receptor negative) and the pancreatic cancer cell line Panc-1 were refractory to the viral cytopathic effect and did not support viral replication. Radioiodine uptake was readily measurable in LnCaP cells infected with Ad5PB_RSV-NIS 24 h post-infection, confirming NIS expression. In vivo, LnCaP tumor xenografts in nude-mice injected intratumorally with Ad5PB_RSV_NIS CRAd expressed NIS actively as evidenced by ⁹⁹Tc uptake and imaging. Administration of therapeutic ¹³¹I after virus injection significantly increased survival probability in mice carrying xenografted LnCaP tumors compared with virotherapy alone. These data indicate that Ad5PB_RSV_NIS replication is stringently restricted to androgen-positive prostate cancer cells and results in effective NIS expression and uptake of radioiodine. This construct may allow multimodal therapy, combining cytolytic virotherapy with radioiodine treatment, to be developed as a novel treatment for prostate cancer.

Show MeSH
Related in: MedlinePlus