Kratzke MG

Purpose: The purpose of this study is to determine the efficacy of inhibition of mitochondrial antioxidant defense against mesothelioma and whether the cyclin-dependent kinase 4 (CDK4) inhibitor palbociclib sensitizes mesothelioma cells to inhibition of mitochondrial antioxidant defense.

Background: Mesothelioma is a highly fatal cancer with limited therapeutic options. Low expression of the endogenous CDK4 inhibitor p16INK4A has been demonstrated in up to 90% of mesothelioma tumors. CDK4 has also been demonstrated to activate manganese superoxide dismutase, which can decrease superoxide levels in cells and may make them less susceptible to induction of apoptosis. Downregulation of the key mitochondrial antioxidant protein, thioredoxin 2 (Trx2) has been demonstrated to increase reactive oxygen species production in mesothelioma cells resulting in reduced mesothelioma tumor growth. Gentian violet has been demonstrated to result in decreased expression of Trx2, a key mitochondrial antioxidant protein. The goal of this project is to determine whether concomitant targeting of the cell cycle and mitochondrial antioxidant pathways lead to improved efficacy against mesothelioma.

Methods: Mesothelioma cells were treated with compound or control and proliferation was evaluated using Cell Counting Kit 8 (Dojindo). For immunoblotting experiments, detection was performed using enhanced chemiluminescence. Apoptosis was detected via Cell Death Detection ELISAPLUS (Sigma-Aldrich). All experiments were done in duplicate or triplicate.

Data Analysis: IC50 curves were fitted via Origin software.

Results: Previously, we have demonstrated that palbociclib inhibits mesothelioma cell proliferation, inhibits retinoblastoma protein (Rb) phosphorylation, and results in cell cycle arrest. Mesothelioma cells in culture were treated with palbociclib and gentian violet alone and in combination. After 72h incubation with gentian violet, decreased cell proliferation was observed for 3 separate cell lines (IC50 = 365 nM, 870 nM, and 920 nM, respectively). Incubation with gentian violet for 24h resulted in decreased expression of Trx2 in all cell lines and also induced apoptosis in all cell lines. Gentian violetsensitized mesothelioma cells to palbociclib in a cell proliferation assay.

Implications: Gentian violet resulted in a significant decrease in mesothelioma cell proliferation. Palbociclib also sensitizes mesothelioma cells to gentian violet. Further investigation of this combination approach may demonstrate these combinations are useful for mesothelioma treatment.

Purpose: The purpose of this study is to determine the efficacy of inhibition of mitochondrial antioxidant defense against mesothelioma and whether the cyclin-dependent kinase 4 (CDK4) inhibitor palbociclib sensitizes mesothelioma cells to inhibition of mitochondrial antioxidant defense.

Background: Mesothelioma is a highly fatal cancer with limited therapeutic options. Low expression of the endogenous CDK4 inhibitor p16INK4A has been demonstrated in up to 90% of mesothelioma tumors. CDK4 has also been demonstrated to activate manganese superoxide dismutase, which can decrease superoxide levels in cells and may make them less susceptible to induction of apoptosis. Downregulation of the key mitochondrial antioxidant protein, thioredoxin 2 (Trx2) has been demonstrated to increase reactive oxygen species production in mesothelioma cells resulting in reduced mesothelioma tumor growth. Gentian violet has been demonstrated to result in decreased expression of Trx2, a key mitochondrial antioxidant protein. The goal of this project is to determine whether concomitant targeting of the cell cycle and mitochondrial antioxidant pathways lead to improved efficacy against mesothelioma.

Methods: Mesothelioma cells were treated with compound or control and proliferation was evaluated using Cell Counting Kit 8 (Dojindo). For immunoblotting experiments, detection was performed using enhanced chemiluminescence. Apoptosis was detected via Cell Death Detection ELISAPLUS (Sigma-Aldrich). All experiments were done in duplicate or triplicate.

Data Analysis: IC50 curves were fitted via Origin software.

Results: Previously, we have demonstrated that palbociclib inhibits mesothelioma cell proliferation, inhibits retinoblastoma protein (Rb) phosphorylation, and results in cell cycle arrest. Mesothelioma cells in culture were treated with palbociclib and gentian violet alone and in combination. After 72h incubation with gentian violet, decreased cell proliferation was observed for 3 separate cell lines (IC50 = 365 nM, 870 nM, and 920 nM, respectively). Incubation with gentian violet for 24h resulted in decreased expression of Trx2 in all cell lines and also induced apoptosis in all cell lines. Gentian violetsensitized mesothelioma cells to palbociclib in a cell proliferation assay.

Implications: Gentian violet resulted in a significant decrease in mesothelioma cell proliferation. Palbociclib also sensitizes mesothelioma cells to gentian violet. Further investigation of this combination approach may demonstrate these combinations are useful for mesothelioma treatment.

Purpose: The purpose of this study is to determine the efficacy of inhibition of mitochondrial antioxidant defense against mesothelioma and whether the cyclin-dependent kinase 4 (CDK4) inhibitor palbociclib sensitizes mesothelioma cells to inhibition of mitochondrial antioxidant defense.

Background: Mesothelioma is a highly fatal cancer with limited therapeutic options. Low expression of the endogenous CDK4 inhibitor p16INK4A has been demonstrated in up to 90% of mesothelioma tumors. CDK4 has also been demonstrated to activate manganese superoxide dismutase, which can decrease superoxide levels in cells and may make them less susceptible to induction of apoptosis. Downregulation of the key mitochondrial antioxidant protein, thioredoxin 2 (Trx2) has been demonstrated to increase reactive oxygen species production in mesothelioma cells resulting in reduced mesothelioma tumor growth. Gentian violet has been demonstrated to result in decreased expression of Trx2, a key mitochondrial antioxidant protein. The goal of this project is to determine whether concomitant targeting of the cell cycle and mitochondrial antioxidant pathways lead to improved efficacy against mesothelioma.

Methods: Mesothelioma cells were treated with compound or control and proliferation was evaluated using Cell Counting Kit 8 (Dojindo). For immunoblotting experiments, detection was performed using enhanced chemiluminescence. Apoptosis was detected via Cell Death Detection ELISAPLUS (Sigma-Aldrich). All experiments were done in duplicate or triplicate.

Data Analysis: IC50 curves were fitted via Origin software.

Results: Previously, we have demonstrated that palbociclib inhibits mesothelioma cell proliferation, inhibits retinoblastoma protein (Rb) phosphorylation, and results in cell cycle arrest. Mesothelioma cells in culture were treated with palbociclib and gentian violet alone and in combination. After 72h incubation with gentian violet, decreased cell proliferation was observed for 3 separate cell lines (IC50 = 365 nM, 870 nM, and 920 nM, respectively). Incubation with gentian violet for 24h resulted in decreased expression of Trx2 in all cell lines and also induced apoptosis in all cell lines. Gentian violetsensitized mesothelioma cells to palbociclib in a cell proliferation assay.

Implications: Gentian violet resulted in a significant decrease in mesothelioma cell proliferation. Palbociclib also sensitizes mesothelioma cells to gentian violet. Further investigation of this combination approach may demonstrate these combinations are useful for mesothelioma treatment.