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Relevance and therapeutic possibility of PTEN-long in renal cell carcinoma.

Wang H, Zhang P, Lin C, Yu Q, Wu J, Wang L, Cui Y, Wang K, Gao Z, Li H - PLoS ONE (2015)

Bottom Line: We found that the protein levels of PTEN-Long were drastically reduced in ccRCC, which was correlated with increased levels of phosphorylated Akt (pAkt).When purified PTEN-Long was added into cultured 786-0 cells, it entered cells, blocked Akt activation, and induced apoptosis involving Caspase 3 cleavage.Furthermore, PTEN-Long inhibited proliferation of 786-0 cells in xenograft mouse model.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, the Affiliated Yantai Yuhuangding Hospital of Qingdao University Medical College, Institute of Urology, Zhifu, Yantai, Shandong, 264000, People's Republic of China.

ABSTRACT
PTEN-Long is a translational variant of PTEN (Phosphatase and Tensin Homolog). Like PTEN, PTEN-Long is able to antagonize the PI3K-Akt pathway and inhibits tumor growth. In this study, we investigated the role PTEN-Long plays in the development and progression of clear cell renal cell carcinoma (ccRCC) and explored the therapeutic possibility using proteinaceous PTEN-Long to treat ccRCC. We found that the protein levels of PTEN-Long were drastically reduced in ccRCC, which was correlated with increased levels of phosphorylated Akt (pAkt). Gain of function experiments showed overexpression of PTEN-Long in the ccRCC cell line 786-0 suppressed PI3K-Akt signaling, inhibited cell proliferation, migration and invasion, and eventually induced cell death. When purified PTEN-Long was added into cultured 786-0 cells, it entered cells, blocked Akt activation, and induced apoptosis involving Caspase 3 cleavage. Furthermore, PTEN-Long inhibited proliferation of 786-0 cells in xenograft mouse model. Our results implicated that understanding the roles of PTEN-Long in renal cell carcinogenesis has therapeutic significance.

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Overexpression of PTEN-Long suppressed PI3K-Akt signaling in 786-0 cells.Western blot analysis of lysates from 786-0 cells showing overexpression of PTEN or PTEN-Long, but not PTENG129R or PTEN-LongG302R, suppressed Akt phosphorylation (Ser473) and its downstream event.
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pone-0114250-g002: Overexpression of PTEN-Long suppressed PI3K-Akt signaling in 786-0 cells.Western blot analysis of lysates from 786-0 cells showing overexpression of PTEN or PTEN-Long, but not PTENG129R or PTEN-LongG302R, suppressed Akt phosphorylation (Ser473) and its downstream event.

Mentions: To characterize the role of PTEN-Long in kidney cancer cells and the mechanisms of tumorigenesis, we stably overexpressed PTEN-Long in 786-0 cells that lacks the PTEN and PTEN-Long gene. In order to avoid co-expression of PTEN-Long and PTEN from PTEN-Long cDNA, we mutated the 5′ initiation site from CTG to ATG and the canonical initiation site from ATG to ATA in PTEN-Long[24]. Cell lysates were then subjected to PTEN, pAkt (Ser473), and Akt immunoblotting analysis. As shown in Fig. 2, the basal levels of Akt phosphorylation were reduced by roughly 90% in PTEN and PTEN-Long expressing cells, compared to empty vector (EV) transfected cells. This indicates PTEN-Long has similar lipid phosphatase activity as PTEN and is able to inhibit PI3K signaling in the cells in which it was expressed. A missense mutation in the phosphatase domain of PTEN-Long (G302R)–analogous to G129R in PTEN, a tumor mutation with depleted phosphatase activity–failed to inhibit Akt phosphorylation (Fig. 2, lanes 1, 4, and 5). Together, the effects of overexpression of equivalent amounts of PTEN, PTEN-Long, or their respective mutated analogs in 786-0 cells confirmed that like PTEN, PTEN-Long is able to suppress PI3K-Akt signaling pathway in a lipid phosphatase-dependent manner.


Relevance and therapeutic possibility of PTEN-long in renal cell carcinoma.

Wang H, Zhang P, Lin C, Yu Q, Wu J, Wang L, Cui Y, Wang K, Gao Z, Li H - PLoS ONE (2015)

Overexpression of PTEN-Long suppressed PI3K-Akt signaling in 786-0 cells.Western blot analysis of lysates from 786-0 cells showing overexpression of PTEN or PTEN-Long, but not PTENG129R or PTEN-LongG302R, suppressed Akt phosphorylation (Ser473) and its downstream event.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4340966&req=5

pone-0114250-g002: Overexpression of PTEN-Long suppressed PI3K-Akt signaling in 786-0 cells.Western blot analysis of lysates from 786-0 cells showing overexpression of PTEN or PTEN-Long, but not PTENG129R or PTEN-LongG302R, suppressed Akt phosphorylation (Ser473) and its downstream event.
Mentions: To characterize the role of PTEN-Long in kidney cancer cells and the mechanisms of tumorigenesis, we stably overexpressed PTEN-Long in 786-0 cells that lacks the PTEN and PTEN-Long gene. In order to avoid co-expression of PTEN-Long and PTEN from PTEN-Long cDNA, we mutated the 5′ initiation site from CTG to ATG and the canonical initiation site from ATG to ATA in PTEN-Long[24]. Cell lysates were then subjected to PTEN, pAkt (Ser473), and Akt immunoblotting analysis. As shown in Fig. 2, the basal levels of Akt phosphorylation were reduced by roughly 90% in PTEN and PTEN-Long expressing cells, compared to empty vector (EV) transfected cells. This indicates PTEN-Long has similar lipid phosphatase activity as PTEN and is able to inhibit PI3K signaling in the cells in which it was expressed. A missense mutation in the phosphatase domain of PTEN-Long (G302R)–analogous to G129R in PTEN, a tumor mutation with depleted phosphatase activity–failed to inhibit Akt phosphorylation (Fig. 2, lanes 1, 4, and 5). Together, the effects of overexpression of equivalent amounts of PTEN, PTEN-Long, or their respective mutated analogs in 786-0 cells confirmed that like PTEN, PTEN-Long is able to suppress PI3K-Akt signaling pathway in a lipid phosphatase-dependent manner.

Bottom Line: We found that the protein levels of PTEN-Long were drastically reduced in ccRCC, which was correlated with increased levels of phosphorylated Akt (pAkt).When purified PTEN-Long was added into cultured 786-0 cells, it entered cells, blocked Akt activation, and induced apoptosis involving Caspase 3 cleavage.Furthermore, PTEN-Long inhibited proliferation of 786-0 cells in xenograft mouse model.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, the Affiliated Yantai Yuhuangding Hospital of Qingdao University Medical College, Institute of Urology, Zhifu, Yantai, Shandong, 264000, People's Republic of China.

ABSTRACT
PTEN-Long is a translational variant of PTEN (Phosphatase and Tensin Homolog). Like PTEN, PTEN-Long is able to antagonize the PI3K-Akt pathway and inhibits tumor growth. In this study, we investigated the role PTEN-Long plays in the development and progression of clear cell renal cell carcinoma (ccRCC) and explored the therapeutic possibility using proteinaceous PTEN-Long to treat ccRCC. We found that the protein levels of PTEN-Long were drastically reduced in ccRCC, which was correlated with increased levels of phosphorylated Akt (pAkt). Gain of function experiments showed overexpression of PTEN-Long in the ccRCC cell line 786-0 suppressed PI3K-Akt signaling, inhibited cell proliferation, migration and invasion, and eventually induced cell death. When purified PTEN-Long was added into cultured 786-0 cells, it entered cells, blocked Akt activation, and induced apoptosis involving Caspase 3 cleavage. Furthermore, PTEN-Long inhibited proliferation of 786-0 cells in xenograft mouse model. Our results implicated that understanding the roles of PTEN-Long in renal cell carcinogenesis has therapeutic significance.

Show MeSH
Related in: MedlinePlus