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Combined treatment with an oncolytic adenovirus and antitumor activity of vincristine against retinoblastoma cells.

Song X, Wang H, Jia R, Cun B, Zhao X, Zhou Y, Xu X, Qian G, Ge S, Fan X - Int J Mol Sci (2012)

Bottom Line: The combination therapy exerted a synergistic antitumor effect via a type of G(2)/M and S phase arrest rather than the induction of apoptosis.The combination of VCR and SG600 further reduced Akt phosphorylation compared with cells treated with VCR alone, suggesting that SG600 could overcome chemoresistance, perhaps by down-regulating Akt in RB cells.An increase in the expression of p-p53 and decrease in p-Rb expression in HXO-RB(44) after co-treatment might be associated with cell cycle block.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China; E-Mails: songxin0521@hotmail.com (X.S.); jrb6@sina.com (R.J.); catherine1_2_3@163.com (B.C.); zxp0856@sina.com (X.Z.); zhouyixiong21@gmail.com (Y.Z.); xuxu0139@hotmail.com (X.X.).

ABSTRACT
Treatment trends of retinoblastoma (RB) have gradually evolved from eye enucleation and external radiation to local treatment. Combined treatment with an oncolytic virus and chemotherapy is currently a new method in RB treatment. To investigate the therapeutic effect of oncolytic adenovirus SG600 in combination with vincristine (VCR) on retinoblastoma in vitro, the cell viability, cell cycle effects and apoptotic activity of HXO-RB(44) cells treated with SG600, VCR or SG600 plus VCR were measured using a cell counting kit-8-based procedure and flow cytometry. Western blot analysis for Akt, p-Akt, p-p53 and p-Rb protein was performed to investigate the underlying mechanisms of combined therapy. The combination therapy exerted a synergistic antitumor effect via a type of G(2)/M and S phase arrest rather than the induction of apoptosis. The combination of VCR and SG600 further reduced Akt phosphorylation compared with cells treated with VCR alone, suggesting that SG600 could overcome chemoresistance, perhaps by down-regulating Akt in RB cells. An increase in the expression of p-p53 and decrease in p-Rb expression in HXO-RB(44) after co-treatment might be associated with cell cycle block. Western blot examination revealed that VCR might enhance SG600 replication. These results suggest that viro-chemo combination therapy is a feasible and potentially promising approach for the treatment of retinoblastoma.

No MeSH data available.


Related in: MedlinePlus

Growth inhibition following treatment with adenovirus (SG600) or vincristine (VCR) on HXO-RB44 (A,B) cells and normal cells (C,D). Bars: standard deviation. The results are representative of three independent experiments and of four replicates in each experiment. ** p < 0.01 relative to the SG600 or VCR treatment group.
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f1-ijms-13-10736: Growth inhibition following treatment with adenovirus (SG600) or vincristine (VCR) on HXO-RB44 (A,B) cells and normal cells (C,D). Bars: standard deviation. The results are representative of three independent experiments and of four replicates in each experiment. ** p < 0.01 relative to the SG600 or VCR treatment group.

Mentions: To examine whether the combination of SG600 and VCR enhances the antitumor effect of either agent alone in an RB cell line, HXO-RB44 cells were exposed to SG600 alone, VCR alone, and SG600 plus VCR. Cell toxicity, measured by the CCK-8 assay, was determined at 96 h after treatment (Figure 1 and 2A). As shown in Figure 1A,B, with increasing doses of SG600 or VCR, the survival rates of HXO-RB44 cells gradually decreased (p < 0.05) compared with the PBS group (NC). In contrast, the survival rates of ARPE-19 cells did not change significantly (Figure 1C) at the same MOIs of SG600, suggesting that SG600 had no significant killing effect on normal cells; however at the same doses of VCR, the survival rates of ARPE-19 were also affected (Figure 1D), showing the side effect of chemotherapy. We then studied the effect of combined treatment with SG600 and VCR. As shown in Figure 2A, compared with the treatment with SG600 or VCR alone, the survival rates of RB cells decreased markedly when treated with the combination of SG600 and VCR in the process with increasing dose. The survival rates of RB cells decreased from 60.48% ± 5.1% (5 nM VCR alone) to 45.12% ± 2.3% (20 MOI SG600 combined with 5 nM VCR) and 43.25% ± 2.4% (50 MOI SG600 combined with 5 nM VCR). With further increase in the dose of VCR (≥10 nM), the survival rates of RB cells treated with the combination of SG600 and VCR did not decrease significantly compared with the treatment with SG600 or VCR alone. Therefore, the dose of VCR was used with 5 nM in subsequent experiments. In another retinoblastoma cell line (WERI-Rb-1) similar results were also observed (data not shown).


Combined treatment with an oncolytic adenovirus and antitumor activity of vincristine against retinoblastoma cells.

Song X, Wang H, Jia R, Cun B, Zhao X, Zhou Y, Xu X, Qian G, Ge S, Fan X - Int J Mol Sci (2012)

Growth inhibition following treatment with adenovirus (SG600) or vincristine (VCR) on HXO-RB44 (A,B) cells and normal cells (C,D). Bars: standard deviation. The results are representative of three independent experiments and of four replicates in each experiment. ** p < 0.01 relative to the SG600 or VCR treatment group.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3472711&req=5

f1-ijms-13-10736: Growth inhibition following treatment with adenovirus (SG600) or vincristine (VCR) on HXO-RB44 (A,B) cells and normal cells (C,D). Bars: standard deviation. The results are representative of three independent experiments and of four replicates in each experiment. ** p < 0.01 relative to the SG600 or VCR treatment group.
Mentions: To examine whether the combination of SG600 and VCR enhances the antitumor effect of either agent alone in an RB cell line, HXO-RB44 cells were exposed to SG600 alone, VCR alone, and SG600 plus VCR. Cell toxicity, measured by the CCK-8 assay, was determined at 96 h after treatment (Figure 1 and 2A). As shown in Figure 1A,B, with increasing doses of SG600 or VCR, the survival rates of HXO-RB44 cells gradually decreased (p < 0.05) compared with the PBS group (NC). In contrast, the survival rates of ARPE-19 cells did not change significantly (Figure 1C) at the same MOIs of SG600, suggesting that SG600 had no significant killing effect on normal cells; however at the same doses of VCR, the survival rates of ARPE-19 were also affected (Figure 1D), showing the side effect of chemotherapy. We then studied the effect of combined treatment with SG600 and VCR. As shown in Figure 2A, compared with the treatment with SG600 or VCR alone, the survival rates of RB cells decreased markedly when treated with the combination of SG600 and VCR in the process with increasing dose. The survival rates of RB cells decreased from 60.48% ± 5.1% (5 nM VCR alone) to 45.12% ± 2.3% (20 MOI SG600 combined with 5 nM VCR) and 43.25% ± 2.4% (50 MOI SG600 combined with 5 nM VCR). With further increase in the dose of VCR (≥10 nM), the survival rates of RB cells treated with the combination of SG600 and VCR did not decrease significantly compared with the treatment with SG600 or VCR alone. Therefore, the dose of VCR was used with 5 nM in subsequent experiments. In another retinoblastoma cell line (WERI-Rb-1) similar results were also observed (data not shown).

Bottom Line: The combination therapy exerted a synergistic antitumor effect via a type of G(2)/M and S phase arrest rather than the induction of apoptosis.The combination of VCR and SG600 further reduced Akt phosphorylation compared with cells treated with VCR alone, suggesting that SG600 could overcome chemoresistance, perhaps by down-regulating Akt in RB cells.An increase in the expression of p-p53 and decrease in p-Rb expression in HXO-RB(44) after co-treatment might be associated with cell cycle block.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China; E-Mails: songxin0521@hotmail.com (X.S.); jrb6@sina.com (R.J.); catherine1_2_3@163.com (B.C.); zxp0856@sina.com (X.Z.); zhouyixiong21@gmail.com (Y.Z.); xuxu0139@hotmail.com (X.X.).

ABSTRACT
Treatment trends of retinoblastoma (RB) have gradually evolved from eye enucleation and external radiation to local treatment. Combined treatment with an oncolytic virus and chemotherapy is currently a new method in RB treatment. To investigate the therapeutic effect of oncolytic adenovirus SG600 in combination with vincristine (VCR) on retinoblastoma in vitro, the cell viability, cell cycle effects and apoptotic activity of HXO-RB(44) cells treated with SG600, VCR or SG600 plus VCR were measured using a cell counting kit-8-based procedure and flow cytometry. Western blot analysis for Akt, p-Akt, p-p53 and p-Rb protein was performed to investigate the underlying mechanisms of combined therapy. The combination therapy exerted a synergistic antitumor effect via a type of G(2)/M and S phase arrest rather than the induction of apoptosis. The combination of VCR and SG600 further reduced Akt phosphorylation compared with cells treated with VCR alone, suggesting that SG600 could overcome chemoresistance, perhaps by down-regulating Akt in RB cells. An increase in the expression of p-p53 and decrease in p-Rb expression in HXO-RB(44) after co-treatment might be associated with cell cycle block. Western blot examination revealed that VCR might enhance SG600 replication. These results suggest that viro-chemo combination therapy is a feasible and potentially promising approach for the treatment of retinoblastoma.

No MeSH data available.


Related in: MedlinePlus