Limits...
Oleanane triterpenoid CDDO-Me induces apoptosis in multidrug resistant osteosarcoma cells through inhibition of Stat3 pathway.

Ryu K, Susa M, Choy E, Yang C, Hornicek FJ, Mankin HJ, Duan Z - BMC Cancer (2010)

Bottom Line: Treatment with CDDO-Me significantly decreased the level of nuclear translocation and phosphorylation of Stat3.Furthermore, CDDO-Me increased the cytotoxic effects of doxorubicin in the MDR osteosarcoma cell lines.This study provides the framework for the clinical evaluation of CDDO-Me, either as monotherapy or perhaps even more effectively in combination with doxorubicin to treat osteosarcoma and overcome drug resistance.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, MA 02114, USA.

ABSTRACT

Background: The activation of signal transducer and activator of transcription 3 (Stat3) pathway correlates with tumor growth, survival, drug resistance and poor prognosis in osteosarcoma. To explore the potential therapeutic values of this pathway, we assessed both the expression and the activation of Stat3 pathway in several pairs of multidrug resistant (MDR) osteosarcoma cell lines, and tissues. To explore the potential therapeutic values of this pathway, we analyzed the ability of the synthetic oleanane triterpenoid, C-28 methyl ester of 2-cyano-3,12-dioxoolen-1,9-dien-28-oic acid (CDDO-Me), to inhibit Stat3 expression and activation as well as its effects on doxorubicin sensitivity in osteosarcoma cells.

Methods: Expression of Stat3, phosphorylated Stat3 (pStat3) and Stat3 targeted proteins, including Bcl-XL, Survivin and MCL-1 were determined in drug sensitive and MDR osteosarcoma cell lines and tissues by Western blot analysis. The effect of CDDO-Me on osteosarcoma cell growth was evaluated by MTT and apoptosis by PARP cleavage assay and caspase-3/7 activity.

Results: Stat3 pathway was activated in osteosarcoma tissues and in MDR cell lines. CDDO-Me inhibited growth and induced apoptosis in osteosarcoma cell lines. Treatment with CDDO-Me significantly decreased the level of nuclear translocation and phosphorylation of Stat3. The inhibition of Stat3 pathway correlated with the suppression of the anti-apoptotic Stat3 targeted genes Bcl-XL, survivin, and MCL-1. Furthermore, CDDO-Me increased the cytotoxic effects of doxorubicin in the MDR osteosarcoma cell lines.

Conclusions: Stat3 pathway is overexpressed in MDR osteosarcoma cells. CDDO-Me significantly inhibited Stat3 phosphorylation, Stat3 nuclear translocation and induced apoptosis in osteosarcoma. This study provides the framework for the clinical evaluation of CDDO-Me, either as monotherapy or perhaps even more effectively in combination with doxorubicin to treat osteosarcoma and overcome drug resistance.

Show MeSH

Related in: MedlinePlus

Activation of Stat3, pStat3, Stat3-mediated antiapoptotic proteins, and Pgp1 in osteosarcoma cell lines and tissues. A) Osteoblast cell lines, drug sensitive and MDR osteosarcoma cell lines. B) Osteosarcoma tissues. Expression was assessed with total cellular protein isolated from the indicated cell lines and immunoblotted with specific antibodies as described in Materials and Methods. The blots were also probed with an anti-actin monoclonal antibody to assess relative protein levels in the sample lanes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2874784&req=5

Figure 1: Activation of Stat3, pStat3, Stat3-mediated antiapoptotic proteins, and Pgp1 in osteosarcoma cell lines and tissues. A) Osteoblast cell lines, drug sensitive and MDR osteosarcoma cell lines. B) Osteosarcoma tissues. Expression was assessed with total cellular protein isolated from the indicated cell lines and immunoblotted with specific antibodies as described in Materials and Methods. The blots were also probed with an anti-actin monoclonal antibody to assess relative protein levels in the sample lanes.

Mentions: To evaluate the expression and activation of Stat3 pathway, we analyzed the protein expression in several pairs of both drug sensitive and MDR osteosarcoma cell lines and 8 samples of osteosarcoma tissues. Western blot analysis demonstrated that Stat3 and pStat3 were constitutively overexpressed in drug sensitive cell lines KHOS, U-2OS, SaOS and MDR cell lines KHOSR2, U-2OSTR. Normal osteoblast cell line HOB-c expressed Stat3 as well as low levels of pStat3 (Fig. 1A). In osteosarcoma tissues, Stat3 was overexpressed in all of the samples and pStat3 was overexpressed in 7 out of 8 (88%) samples (Fig. 1B). Following this preliminary study, we analyzed the expression of Stat3-mediated antiapoptotic proteins Bcl-XL, survivin, and MCL-1. Western blot analysis demonstrated that Bcl-XL, survivin, and MCL-1 were constitutively overexpressed in drug sensitive cell lines and MDR osteosarcoma cell lines. Osteoblast cell lines HOB-c controls showed no expression of Stat3-mediated anti-apoptotic proteins. Pgp1 is also over expressed in MDR cell lines (Fig. 1A). Osteosarcoma tissues showed heterogeneous expression of Stat3 mediated antiapoptotic proteins and Pgp1 (Fig. 1B).


Oleanane triterpenoid CDDO-Me induces apoptosis in multidrug resistant osteosarcoma cells through inhibition of Stat3 pathway.

Ryu K, Susa M, Choy E, Yang C, Hornicek FJ, Mankin HJ, Duan Z - BMC Cancer (2010)

Activation of Stat3, pStat3, Stat3-mediated antiapoptotic proteins, and Pgp1 in osteosarcoma cell lines and tissues. A) Osteoblast cell lines, drug sensitive and MDR osteosarcoma cell lines. B) Osteosarcoma tissues. Expression was assessed with total cellular protein isolated from the indicated cell lines and immunoblotted with specific antibodies as described in Materials and Methods. The blots were also probed with an anti-actin monoclonal antibody to assess relative protein levels in the sample lanes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2874784&req=5

Figure 1: Activation of Stat3, pStat3, Stat3-mediated antiapoptotic proteins, and Pgp1 in osteosarcoma cell lines and tissues. A) Osteoblast cell lines, drug sensitive and MDR osteosarcoma cell lines. B) Osteosarcoma tissues. Expression was assessed with total cellular protein isolated from the indicated cell lines and immunoblotted with specific antibodies as described in Materials and Methods. The blots were also probed with an anti-actin monoclonal antibody to assess relative protein levels in the sample lanes.
Mentions: To evaluate the expression and activation of Stat3 pathway, we analyzed the protein expression in several pairs of both drug sensitive and MDR osteosarcoma cell lines and 8 samples of osteosarcoma tissues. Western blot analysis demonstrated that Stat3 and pStat3 were constitutively overexpressed in drug sensitive cell lines KHOS, U-2OS, SaOS and MDR cell lines KHOSR2, U-2OSTR. Normal osteoblast cell line HOB-c expressed Stat3 as well as low levels of pStat3 (Fig. 1A). In osteosarcoma tissues, Stat3 was overexpressed in all of the samples and pStat3 was overexpressed in 7 out of 8 (88%) samples (Fig. 1B). Following this preliminary study, we analyzed the expression of Stat3-mediated antiapoptotic proteins Bcl-XL, survivin, and MCL-1. Western blot analysis demonstrated that Bcl-XL, survivin, and MCL-1 were constitutively overexpressed in drug sensitive cell lines and MDR osteosarcoma cell lines. Osteoblast cell lines HOB-c controls showed no expression of Stat3-mediated anti-apoptotic proteins. Pgp1 is also over expressed in MDR cell lines (Fig. 1A). Osteosarcoma tissues showed heterogeneous expression of Stat3 mediated antiapoptotic proteins and Pgp1 (Fig. 1B).

Bottom Line: Treatment with CDDO-Me significantly decreased the level of nuclear translocation and phosphorylation of Stat3.Furthermore, CDDO-Me increased the cytotoxic effects of doxorubicin in the MDR osteosarcoma cell lines.This study provides the framework for the clinical evaluation of CDDO-Me, either as monotherapy or perhaps even more effectively in combination with doxorubicin to treat osteosarcoma and overcome drug resistance.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, MA 02114, USA.

ABSTRACT

Background: The activation of signal transducer and activator of transcription 3 (Stat3) pathway correlates with tumor growth, survival, drug resistance and poor prognosis in osteosarcoma. To explore the potential therapeutic values of this pathway, we assessed both the expression and the activation of Stat3 pathway in several pairs of multidrug resistant (MDR) osteosarcoma cell lines, and tissues. To explore the potential therapeutic values of this pathway, we analyzed the ability of the synthetic oleanane triterpenoid, C-28 methyl ester of 2-cyano-3,12-dioxoolen-1,9-dien-28-oic acid (CDDO-Me), to inhibit Stat3 expression and activation as well as its effects on doxorubicin sensitivity in osteosarcoma cells.

Methods: Expression of Stat3, phosphorylated Stat3 (pStat3) and Stat3 targeted proteins, including Bcl-XL, Survivin and MCL-1 were determined in drug sensitive and MDR osteosarcoma cell lines and tissues by Western blot analysis. The effect of CDDO-Me on osteosarcoma cell growth was evaluated by MTT and apoptosis by PARP cleavage assay and caspase-3/7 activity.

Results: Stat3 pathway was activated in osteosarcoma tissues and in MDR cell lines. CDDO-Me inhibited growth and induced apoptosis in osteosarcoma cell lines. Treatment with CDDO-Me significantly decreased the level of nuclear translocation and phosphorylation of Stat3. The inhibition of Stat3 pathway correlated with the suppression of the anti-apoptotic Stat3 targeted genes Bcl-XL, survivin, and MCL-1. Furthermore, CDDO-Me increased the cytotoxic effects of doxorubicin in the MDR osteosarcoma cell lines.

Conclusions: Stat3 pathway is overexpressed in MDR osteosarcoma cells. CDDO-Me significantly inhibited Stat3 phosphorylation, Stat3 nuclear translocation and induced apoptosis in osteosarcoma. This study provides the framework for the clinical evaluation of CDDO-Me, either as monotherapy or perhaps even more effectively in combination with doxorubicin to treat osteosarcoma and overcome drug resistance.

Show MeSH
Related in: MedlinePlus