Limits...
Loss of RASSF2 Enhances Tumorigencity of Lung Cancer Cells and Confers Resistance to Chemotherapy.

Clark J, Freeman J, Donninger H - Mol Biol Int (2012)

Bottom Line: RASSF2 is a novel pro-apoptotic effector of K-Ras that is frequently inactivated in a variety of primary tumors by promoter methylation.In this study, we confirm that RASSF2 and K-Ras form an endogenous complex, validating that RASSF2 is a bona fide K-Ras effector.Loss of RASSF2 expression resulted in a more aggressive phenotype that was characterized by enhanced cell proliferation and invasion, decreased cell adhesion, the ability to grow in an anchorage-independent manner and cell morphological changes.

View Article: PubMed Central - PubMed

Affiliation: Molecular Targets Program, Department of Medicine, James Graham Brown Cancer Center, University of Louisville, 505 S. Hancock Street, Louisville, KY 40202, USA.

ABSTRACT
RASSF2 is a novel pro-apoptotic effector of K-Ras that is frequently inactivated in a variety of primary tumors by promoter methylation. Inactivation of RASSF2 enhances K-Ras-mediated transformation and overexpression of RASSF2 suppresses tumor cell growth. In this study, we confirm that RASSF2 and K-Ras form an endogenous complex, validating that RASSF2 is a bona fide K-Ras effector. We adopted an RNAi approach to determine the effects of inactivation of RASSF2 on the transformed phenotype of lung cancer cells containing an oncogenic K-Ras. Loss of RASSF2 expression resulted in a more aggressive phenotype that was characterized by enhanced cell proliferation and invasion, decreased cell adhesion, the ability to grow in an anchorage-independent manner and cell morphological changes. This enhanced transformed phenotype of the cells correlated with increased levels of activated AKT, indicating that RASSF2 can modulate Ras signaling pathways. Loss of RASSF2 expression also confers resistance to taxol and cisplatin, two frontline therapeutics for the treatment of lung cancer. Thus we have shown that inactivation of RASSF2, a process that occurs frequently in primary tumors, enhances the transforming potential of activated K-Ras and our data suggests that RASSF2 may be a novel candidate for epigenetic-based therapy in lung cancer.

No MeSH data available.


Related in: MedlinePlus

Inactivation of RASSF2 confers resistance to cisplatin and taxol. H441 cells stably transfected with control and RASSF2 shRNA constructs were seeded at 2 × 104 cells per well in 12-well plates and treated with 5 nM taxol or 10 μM cisplatin for 3 days. Cell death was estimated by trypan blue exclusion. Cells stably transfected with the RASSF2 shRNA showed significantly less cell death (P < 0.05) compared to the control cells for both taxol and cisplatin treatments.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3368207&req=5

fig6: Inactivation of RASSF2 confers resistance to cisplatin and taxol. H441 cells stably transfected with control and RASSF2 shRNA constructs were seeded at 2 × 104 cells per well in 12-well plates and treated with 5 nM taxol or 10 μM cisplatin for 3 days. Cell death was estimated by trypan blue exclusion. Cells stably transfected with the RASSF2 shRNA showed significantly less cell death (P < 0.05) compared to the control cells for both taxol and cisplatin treatments.

Mentions: To determine whether the more aggressive phenotype of the RASSF2 knockdown cells altered their response to chemotherapeutic agents, we treated the cells with taxol or cisplatin, two drugs commonly used in the treatment of nonsmall cell lung cancer, and measured their effects on cell death. Both taxol and cisplatin resulted in increased cell death in the control cells by approximately 40% and 50%, respectively. However, in the cells stably knocked down for RASSF2, taxol had no effect on cell growth and the cisplatin-induced cell death was somewhat abrogated (Figure 6). Thus, loss of RASSF2 expression confers resistance to taxol and cisplatin.


Loss of RASSF2 Enhances Tumorigencity of Lung Cancer Cells and Confers Resistance to Chemotherapy.

Clark J, Freeman J, Donninger H - Mol Biol Int (2012)

Inactivation of RASSF2 confers resistance to cisplatin and taxol. H441 cells stably transfected with control and RASSF2 shRNA constructs were seeded at 2 × 104 cells per well in 12-well plates and treated with 5 nM taxol or 10 μM cisplatin for 3 days. Cell death was estimated by trypan blue exclusion. Cells stably transfected with the RASSF2 shRNA showed significantly less cell death (P < 0.05) compared to the control cells for both taxol and cisplatin treatments.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368207&req=5

fig6: Inactivation of RASSF2 confers resistance to cisplatin and taxol. H441 cells stably transfected with control and RASSF2 shRNA constructs were seeded at 2 × 104 cells per well in 12-well plates and treated with 5 nM taxol or 10 μM cisplatin for 3 days. Cell death was estimated by trypan blue exclusion. Cells stably transfected with the RASSF2 shRNA showed significantly less cell death (P < 0.05) compared to the control cells for both taxol and cisplatin treatments.
Mentions: To determine whether the more aggressive phenotype of the RASSF2 knockdown cells altered their response to chemotherapeutic agents, we treated the cells with taxol or cisplatin, two drugs commonly used in the treatment of nonsmall cell lung cancer, and measured their effects on cell death. Both taxol and cisplatin resulted in increased cell death in the control cells by approximately 40% and 50%, respectively. However, in the cells stably knocked down for RASSF2, taxol had no effect on cell growth and the cisplatin-induced cell death was somewhat abrogated (Figure 6). Thus, loss of RASSF2 expression confers resistance to taxol and cisplatin.

Bottom Line: RASSF2 is a novel pro-apoptotic effector of K-Ras that is frequently inactivated in a variety of primary tumors by promoter methylation.In this study, we confirm that RASSF2 and K-Ras form an endogenous complex, validating that RASSF2 is a bona fide K-Ras effector.Loss of RASSF2 expression resulted in a more aggressive phenotype that was characterized by enhanced cell proliferation and invasion, decreased cell adhesion, the ability to grow in an anchorage-independent manner and cell morphological changes.

View Article: PubMed Central - PubMed

Affiliation: Molecular Targets Program, Department of Medicine, James Graham Brown Cancer Center, University of Louisville, 505 S. Hancock Street, Louisville, KY 40202, USA.

ABSTRACT
RASSF2 is a novel pro-apoptotic effector of K-Ras that is frequently inactivated in a variety of primary tumors by promoter methylation. Inactivation of RASSF2 enhances K-Ras-mediated transformation and overexpression of RASSF2 suppresses tumor cell growth. In this study, we confirm that RASSF2 and K-Ras form an endogenous complex, validating that RASSF2 is a bona fide K-Ras effector. We adopted an RNAi approach to determine the effects of inactivation of RASSF2 on the transformed phenotype of lung cancer cells containing an oncogenic K-Ras. Loss of RASSF2 expression resulted in a more aggressive phenotype that was characterized by enhanced cell proliferation and invasion, decreased cell adhesion, the ability to grow in an anchorage-independent manner and cell morphological changes. This enhanced transformed phenotype of the cells correlated with increased levels of activated AKT, indicating that RASSF2 can modulate Ras signaling pathways. Loss of RASSF2 expression also confers resistance to taxol and cisplatin, two frontline therapeutics for the treatment of lung cancer. Thus we have shown that inactivation of RASSF2, a process that occurs frequently in primary tumors, enhances the transforming potential of activated K-Ras and our data suggests that RASSF2 may be a novel candidate for epigenetic-based therapy in lung cancer.

No MeSH data available.


Related in: MedlinePlus