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Targeting DDX3 with a small molecule inhibitor for lung cancer therapy.

Bol GM, Vesuna F, Xie M, Zeng J, Aziz K, Gandhi N, Levine A, Irving A, Korz D, Tantravedi S, Heerma van Voss MR, Gabrielson K, Bordt EA, Polster BM, Cope L, van der Groep P, Kondaskar A, Rudek MA, Hosmane RS, van der Wall E, van Diest PJ, Tran PT, Raman V - EMBO Mol Med (2015)

Bottom Line: We designed a first-in-class small molecule inhibitor, RK-33, which binds to DDX3 and abrogates its activity.Mechanistically, loss of DDX3 function either by shRNA or by RK-33 impaired Wnt signaling through disruption of the DDX3-β-catenin axis and inhibited non-homologous end joining-the major DNA repair pathway in mammalian somatic cells.Overall, inhibition of DDX3 by RK-33 promotes tumor regression, thus providing a compelling argument to develop DDX3 inhibitors for lung cancer therapy.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands.

No MeSH data available.


Related in: MedlinePlus

Effect of DDX3 knockdown and RK-33 on cell cycle progression and apoptosisA Cell cycle analysis of H1299 cells treated with shDDX3 and processed by flow cytometry. Knockdown of DDX3 led to a decrease of cells in S-phase and an increase of cells in G1-phase, indicative of a G1 arrest. Significance was assessed by two-sided, unpaired t-test. Error bars represent SD.B, C Cell cycle analysis of A549 and H1299 cells by flow cytometry after treatment with RK-33 (0, 2, 4, and 6 μM). RK-33 induced a G1 cell cycle arrest in both cell lines. Significance was assessed by two-sided, unpaired t-test. Error bars represent SD.D, E Immunoblot of cell cycle-related proteins (Cyclin D1 and Cyclin E1) and cell death-related proteins (cleaved caspase 7, cleaved caspase 9) in A549 and H1299 cells after treatment with RK-33 (10 μM). Initially, a strong decrease of Cyclin D1 was observed. After 8 and 24 h, cleaved caspases 9 and 7 were apparent.F Immunoblot of MAPK pathway-related proteins ERK1/2 and phosphorylated ERK1/2 in A549, H1299, and H3255 (RK-33 resistant) cells 24 h after treatment with RK-33 (7.5 μM or 10 μM). ERK2 and especially ERK1 become dephosphorylated after treatment with RK-33 in A549 and H1299 cells but not in H3255 cells. Outlined boxes indicate spliced lanes.Source data are available online for this figure.
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fig07: Effect of DDX3 knockdown and RK-33 on cell cycle progression and apoptosisA Cell cycle analysis of H1299 cells treated with shDDX3 and processed by flow cytometry. Knockdown of DDX3 led to a decrease of cells in S-phase and an increase of cells in G1-phase, indicative of a G1 arrest. Significance was assessed by two-sided, unpaired t-test. Error bars represent SD.B, C Cell cycle analysis of A549 and H1299 cells by flow cytometry after treatment with RK-33 (0, 2, 4, and 6 μM). RK-33 induced a G1 cell cycle arrest in both cell lines. Significance was assessed by two-sided, unpaired t-test. Error bars represent SD.D, E Immunoblot of cell cycle-related proteins (Cyclin D1 and Cyclin E1) and cell death-related proteins (cleaved caspase 7, cleaved caspase 9) in A549 and H1299 cells after treatment with RK-33 (10 μM). Initially, a strong decrease of Cyclin D1 was observed. After 8 and 24 h, cleaved caspases 9 and 7 were apparent.F Immunoblot of MAPK pathway-related proteins ERK1/2 and phosphorylated ERK1/2 in A549, H1299, and H3255 (RK-33 resistant) cells 24 h after treatment with RK-33 (7.5 μM or 10 μM). ERK2 and especially ERK1 become dephosphorylated after treatment with RK-33 in A549 and H1299 cells but not in H3255 cells. Outlined boxes indicate spliced lanes.Source data are available online for this figure.

Mentions: As loss of DDX3 altered proliferation, we performed cell cycle analysis by flow cytometry, following biological knockdown of DDX3 by shDDX3 and by RK-33 treatment. We found a 13.7% (P = 0.006) decrease in S-phase and a 14.1% (P = 0.0007) increase in G1-phase in H1299 DDX3 knockdown cells (Fig7A), consistent with a G1 arrest. Similarly, treatment with RK-33 also resulted in a G1 arrest of A549 and H1299 cells in a dose-dependent manner (Fig7B and C).


Targeting DDX3 with a small molecule inhibitor for lung cancer therapy.

Bol GM, Vesuna F, Xie M, Zeng J, Aziz K, Gandhi N, Levine A, Irving A, Korz D, Tantravedi S, Heerma van Voss MR, Gabrielson K, Bordt EA, Polster BM, Cope L, van der Groep P, Kondaskar A, Rudek MA, Hosmane RS, van der Wall E, van Diest PJ, Tran PT, Raman V - EMBO Mol Med (2015)

Effect of DDX3 knockdown and RK-33 on cell cycle progression and apoptosisA Cell cycle analysis of H1299 cells treated with shDDX3 and processed by flow cytometry. Knockdown of DDX3 led to a decrease of cells in S-phase and an increase of cells in G1-phase, indicative of a G1 arrest. Significance was assessed by two-sided, unpaired t-test. Error bars represent SD.B, C Cell cycle analysis of A549 and H1299 cells by flow cytometry after treatment with RK-33 (0, 2, 4, and 6 μM). RK-33 induced a G1 cell cycle arrest in both cell lines. Significance was assessed by two-sided, unpaired t-test. Error bars represent SD.D, E Immunoblot of cell cycle-related proteins (Cyclin D1 and Cyclin E1) and cell death-related proteins (cleaved caspase 7, cleaved caspase 9) in A549 and H1299 cells after treatment with RK-33 (10 μM). Initially, a strong decrease of Cyclin D1 was observed. After 8 and 24 h, cleaved caspases 9 and 7 were apparent.F Immunoblot of MAPK pathway-related proteins ERK1/2 and phosphorylated ERK1/2 in A549, H1299, and H3255 (RK-33 resistant) cells 24 h after treatment with RK-33 (7.5 μM or 10 μM). ERK2 and especially ERK1 become dephosphorylated after treatment with RK-33 in A549 and H1299 cells but not in H3255 cells. Outlined boxes indicate spliced lanes.Source data are available online for this figure.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4492822&req=5

fig07: Effect of DDX3 knockdown and RK-33 on cell cycle progression and apoptosisA Cell cycle analysis of H1299 cells treated with shDDX3 and processed by flow cytometry. Knockdown of DDX3 led to a decrease of cells in S-phase and an increase of cells in G1-phase, indicative of a G1 arrest. Significance was assessed by two-sided, unpaired t-test. Error bars represent SD.B, C Cell cycle analysis of A549 and H1299 cells by flow cytometry after treatment with RK-33 (0, 2, 4, and 6 μM). RK-33 induced a G1 cell cycle arrest in both cell lines. Significance was assessed by two-sided, unpaired t-test. Error bars represent SD.D, E Immunoblot of cell cycle-related proteins (Cyclin D1 and Cyclin E1) and cell death-related proteins (cleaved caspase 7, cleaved caspase 9) in A549 and H1299 cells after treatment with RK-33 (10 μM). Initially, a strong decrease of Cyclin D1 was observed. After 8 and 24 h, cleaved caspases 9 and 7 were apparent.F Immunoblot of MAPK pathway-related proteins ERK1/2 and phosphorylated ERK1/2 in A549, H1299, and H3255 (RK-33 resistant) cells 24 h after treatment with RK-33 (7.5 μM or 10 μM). ERK2 and especially ERK1 become dephosphorylated after treatment with RK-33 in A549 and H1299 cells but not in H3255 cells. Outlined boxes indicate spliced lanes.Source data are available online for this figure.
Mentions: As loss of DDX3 altered proliferation, we performed cell cycle analysis by flow cytometry, following biological knockdown of DDX3 by shDDX3 and by RK-33 treatment. We found a 13.7% (P = 0.006) decrease in S-phase and a 14.1% (P = 0.0007) increase in G1-phase in H1299 DDX3 knockdown cells (Fig7A), consistent with a G1 arrest. Similarly, treatment with RK-33 also resulted in a G1 arrest of A549 and H1299 cells in a dose-dependent manner (Fig7B and C).

Bottom Line: We designed a first-in-class small molecule inhibitor, RK-33, which binds to DDX3 and abrogates its activity.Mechanistically, loss of DDX3 function either by shRNA or by RK-33 impaired Wnt signaling through disruption of the DDX3-β-catenin axis and inhibited non-homologous end joining-the major DNA repair pathway in mammalian somatic cells.Overall, inhibition of DDX3 by RK-33 promotes tumor regression, thus providing a compelling argument to develop DDX3 inhibitors for lung cancer therapy.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands.

No MeSH data available.


Related in: MedlinePlus