Checkpoint Kinase 1 Down-Regulation by an Inducible Small Interfering RNA Expression System Sensitized <i>In vivo</i> Tumors to Treatment with 5-Fluorouracil

Ganzinelli, Monica; Carrassa, Laura; Crippa, Francesca; Tavecchio, Michele; Broggini, Massimo; Damia, Giovanna

doi:10.1158/1078-0432.ccr-08-0304

Cited by 43 publications

(33 citation statements)

References 36 publications

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“…4), consistent with results from other cell lines. 24,26 LDM induced G 1 and G 2 /M arrests in control mock shRNA-transfected p53 wt cells, and G 2 /M arrest in control mock shRNA-transfected p53 -/-cells (Fig. 4A).…”

Section: Resultsmentioning

confidence: 90%

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Knockdown of Chk1 sensitizes human colon carcinoma HCT116 cells in a p53-dependent manner to lidamycin through abrogation of a G2/M checkpoint and induction of apoptosis

Pan¹,

Ren²,

He³

et al. 2009

Cancer Biology & Therapy

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Recent advances in cell cycle regulation have led to a suggestion of therapeutically targeting cell cycle checkpoint pathways in cancer cells to increase the toxicity of DNA-damaging agents. In this study, we investigate whether knockdowns of checkpoint kinases Chk1 and Chk2 by RNA interfering potentiate the cytotoxicity and abrogate G 2 /M checkpoint induced by DNA-damaging agent lidamycin (LDM) in HCT116 cells with different p53 status. Our results showed that Chk1 knockdown enhanced the cytotoxicity of LDM through abrogating G 2 /M arrest and increasing apoptosis to a greater extent in HCT116 p53 -/-cells than in p53 wt cells. Abrogation of LDM-induced G 2 /M arrest by Chk1 knockdown was associated with reducing the inactivated phosphorylations of Cdc25C and Cdc2. LDM-induced γ-H2AX was increased in cells with Chk1 knockdown, indicating that DNA double-strand breaks (DSBs) were enhanced. Furthermore, knockdown of Chk1 also increased LDM-mediated apoptotic cell death in p53 knockout cells with activation of caspase-2 and caspase-3. On the contrary, knockdown of Chk2 had no impact on G 2 /M arrest or apoptosis induced by LDM. Moreover, dual knockdown of Chk1 and Chk2 failed to achieve better efficacy than Chk1 alone. Taken together, we suggest that Chk1 is a potential therapeutic target to sensitize human p53 deficient cancer cells to LDM.

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Section: Resultsmentioning

confidence: 90%

“…17,[24][25][26] So we investigated whether knockdowns of Chk1 and/or Chk2 could increase the sensitivity of tumor cells to DNA damaging agent LDM. As shown in Figure 3B, LDM-induced growth inhibition was markedly enhanced in Chk1 shRNA-and Chk1/2 shRNA-transfected HCT116 p53 wt or p53 -/-cells.…”

Section: Resultsmentioning

confidence: 99%

Knockdown of Chk1 sensitizes human colon carcinoma HCT116 cells in a p53-dependent manner to lidamycin through abrogation of a G2/M checkpoint and induction of apoptosis

Pan¹,

Ren²,

He³

et al. 2009

Cancer Biology & Therapy

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“…More recently, inhibition of CHK1 function by knockdown of protein expression by small interfering RNA and several more selective CHK1 inhibitors have confirmed these early observations (19)(20)(21). As a part of the development of molecularly targeted kinase inhibitors, particularly those that might not have antitumor activity in their own right, it is important to identify appropriate biomarker readouts (22,23).…”

Section: Molecular Cancer Therapeuticsmentioning

confidence: 87%

The Preclinical Pharmacology and Therapeutic Activity of the Novel CHK1 Inhibitor SAR-020106

Walton

Eve

Hayes

et al. 2010

Molecular Cancer Therapeutics

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Genotoxic antitumor agents continue to be the mainstay of current cancer chemotherapy. These drugs cause DNA damage and activate numerous cell cycle checkpoints facilitating DNA repair and the maintenance of genomic integrity. Most human tumors lack functional p53 and consequently have compromised G 1 -S checkpoint control. This has led to the hypothesis that S and G 2 -M checkpoint abrogation may selectively enhance genotoxic cell killing in a p53-deficient background, as normal cells would be rescued at the G 1 -S checkpoint. CHK1 is a serine/threonine kinase associated with DNA damage-linked S and G 2 -M checkpoint control. SAR-020106 is an ATP-competitive, potent, and selective CHK1 inhibitor with an IC 50 of 13.3 nmol/L on the isolated human enzyme. This compound abrogates an etoposide-induced G 2 arrest with an IC 50 of 55 nmol/L in HT29 cells, and significantly enhances the cell killing of gemcitabine and SN38 by 3.0-to 29-fold in several colon tumor lines in vitro and in a p53-dependent fashion. Biomarker studies have shown that SAR-020106 inhibits cytotoxic drug-induced autophosphorylation of CHK1 at S296 and blocks the phosphorylation of CDK1 at Y15 in a dose-dependent fashion both in vitro and in vivo. Cytotoxic drug combinations were associated with increased γH2AX and poly ADP ribose polymerase cleavage consistent with the SAR-020106-enhanced DNA damage and tumor cell death. Irinotecan and gemcitabine antitumor activity was enhanced by SAR-020106 in vivo with minimal toxicity. SAR-020106 represents a novel class of CHK1 inhibitors that can enhance antitumor activity with selected anticancer drugs in vivo and may therefore have clinical utility.

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“…HCT116 cell lines have previously been generated that express CHK1 siRNA or a scrambled control siRNA under the control of a tetracycline-responsive promoter (Ganzinelli et al, 2008). When cultured in the presence of doxycycline, levels of CHK1 protein were knocked down by over 75% as estimated by immunoblot (Fig.…”

Section: Chk1 Impairs G2 Cell Cycle Progression During Er Stressmentioning

confidence: 99%

Impaired tissue growth is mediated by checkpoint kinase 1 (CHK1) in the integrated stress response

Malzer

Daly

Moloney

et al. 2010

Journal of Cell Science

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SummaryThe integrated stress response (ISR) protects cells from numerous forms of stress and is involved in the growth of solid tumours; however, it is unclear how the ISR acts on cellular proliferation. We have developed a model of ISR signalling with which to study its effects on tissue growth. Overexpression of the ISR kinase PERK resulted in a striking atrophic eye phenotype in Drosophila melanogaster that could be rescued by co-expressing the eIF2 phosphatase GADD34. A genetic screen of 3000 transposon insertions identified grapes, the gene that encodes the Drosophila orthologue of checkpoint kinase 1 (CHK1). Knockdown of grapes by RNAi rescued eye development despite ongoing PERK activation. In mammalian cells, CHK1 was activated by agents that induce ER stress, which resulted in a G2 cell cycle delay. PERK was both necessary and sufficient for CHK1 activation. These findings indicate that non-genotoxic misfolded protein stress accesses DNA-damage-induced cell cycle checkpoints to couple the ISR to cell cycle arrest.

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Checkpoint Kinase 1 Down-Regulation by an Inducible Small Interfering RNA Expression System Sensitized In vivo Tumors to Treatment with 5-Fluorouracil

Cited by 43 publications

References 36 publications

Knockdown of Chk1 sensitizes human colon carcinoma HCT116 cells in a p53-dependent manner to lidamycin through abrogation of a G2/M checkpoint and induction of apoptosis

Knockdown of Chk1 sensitizes human colon carcinoma HCT116 cells in a p53-dependent manner to lidamycin through abrogation of a G2/M checkpoint and induction of apoptosis

The Preclinical Pharmacology and Therapeutic Activity of the Novel CHK1 Inhibitor SAR-020106

Impaired tissue growth is mediated by checkpoint kinase 1 (CHK1) in the integrated stress response

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