Preclinical study of trabectedin (TR) and poly(ADP-ribose)polymerase 1 (PARP-1) inhibitor combination in soft tissue sarcoma (STS).

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 10066-10066
Author(s):  
Ymera Pignochino ◽  
Federica Capozzi ◽  
Carmine Dell' Aglio ◽  
Marco Basiricò ◽  
Loredana Tarraran ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Viability ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Excision Repair ◽  
Repair Mechanism ◽  
Cycle Arrest ◽  
G2 Cell Cycle Arrest ◽  
Parp 1

10066 Background: TR is an alkylating agent approved in Europe for the treatment of advanced STS as second/third line therapy. TR binds to the minor groove of DNA and interferes with gene transcription and nucleotide excision repair mechanism, inducing DNA double strand breaks (DSBs), and S/G2 cell cycle arrest. There is a strong clinical interest to increase TR activity combining it with other anti-cancer drugs. PARP-1 inhibitors disable DNA base-excision repair mechanism causing the accumulation of DSBs and look like a reasonable TR partner to be explored. We focused our in vitro studies on the effects of the combination of TR with the PARP-1 inhibitor Olaparib (OL). Methods: We explored the activity of TR-OL combination against a panel of different histotypes of STS cell lines, evaluating cell viability after 72h treatment with escalating doses of TR (0-2 nM), OL (0-20 µM), and their constant combination. Following colony formation, cell cycle, apoptosis (annexin V+/PI+) and DNA damage (phospho-histone H2AX - Ser139) were checked. Results: The TR-OL combination strongly affects STS cell viability, showing synergism (Combination Index < 1, based on Chou–Talalay method) on 8 out of 13 cell lines tested. We observed a strong synergism, as a massive reduction of colony growth (402.91, MES-SA, and DMR-SN-8.4.98 lines) induced by the combination if compared with each single agent (78% vs. ~27% : p<0.05). OL potentiates the S/G2 cell-cycle arrest caused by TR at 48h (Control= 29%, TR= 33.4%, OL= 31.5%, TR-OL= 80.9%), and induces a strong increase of the apoptotic cells at 72h (Control= 17.4%, TR= 28.3%, OL= 33.5%, TR-OL= 56.8%). Furthermore, the TR-OL synergism on DNA damage is confirmed by a significant increase of the DSBs marker (Control= 8.7%, TR= 59.5%, OL= 23.8%, TR-OL= 76.5%). Conclusions: These results validate the biological rationale to combine TR and PARP-1 inhibitors in STS and suggest assessing this drug combination in the clinical setting.

Cdc7 inhibition as a novel approach for pancreas cancer therapy.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e15059-e15059
Author(s):  
Mark G. Frattini ◽  
Lucia Regales ◽  
Ruth Santos ◽  
Diana Carrillo
Keyword(s):  
Cell Cycle ◽  
Pancreatic Cancer ◽  
Dna Damage ◽  
Cell Viability ◽  
Cell Cycle Arrest ◽  
Western Blotting ◽  
Kinase Activity ◽  
S Phase ◽  
Cycle Arrest ◽  
Cdc7 Kinase

e15059 Background: Pancreatic cancer is the fourth leading cause of cancer death in the USA. In 2012, 43,920 people will be diagnosed and 37,390 people will die of this disease. 95% of tumors reveal loss of the p16 protein, a regulator of the G1 to S phase transition. Cdc7 is a conserved kinase required for the initiation of DNA replication, is a target of the S-phase checkpoint, and has a role in controlling the DNA damage response. Downregulation of Cdc7 kinase activity resulted in slowing of S-phase and cell cycle arrest followed by accumulation of DNA damage. Cdc7 has been shown to be over-expressed in many different tumors including the majority of solid and liquid tumors. In our laboratory a novel natural product small molecule inhibitor (MSK-777) has been identified, developed and shown to be efficacious in cell based cytotoxicity assays and multiple animal models of cancer. Methods: We have examined the efficacy of Cdc7 kinase inhibition as a therapeutic approach for pancreatic cancer by examining the sensitivity of MSK-777 in Capan-1, BxPC3, and PANC-1 cell lines. These cells were treated with MSK-777, control (DMSO), or hydroxyurea and collected for viable cell counts, fluorescence-activated cell sorting (FACS), and western blotting. Results: Cell viability analyses revealed that MSK-777 had a dramatic effect after 24 hours, reducing cell viability to less then 20% in BxPC3 cells. FACS results demonstrated that MSK-777 exposure resulted in cell cycle arrest at G1/S in Capan-1 and PANC-1 cells by 48 hours while BxPC3 cells showed a significant sub-G1 population by 24 hours, indicating apoptotic cell death. Western blotting showed that in BxPC3 cells phosphorylation of the mini-chromosome maintenance 2 protein (Mcm2) disappeared by 24 hours, indicating inactivation of the helicase that unwinds the strands of DNA during replication. Western blots of Capan-1 and PANC-1 cells showed lower levels of phosphorylated Mcm2 by 48 hours. Conclusions: We are currently examining the efficacy of MSK-777 in mouse models of orthotopically injected pancreatic cancer cells. Based on these collective results, inhibition of Cdc7 kinase activity with MSK-777 represents a novel and promising therapy for this deadly disease.

Induction of DNA Damage and G2 Cell Cycle Arrest by Diepoxybutane through the Activation of the Chk1-Dependent Pathway in Mouse Germ Cells

2015 ◽  
Vol 28 (3) ◽  
pp. 518-531 ◽  
Author(s):  
Jianyun Dong ◽  
Zhi Wang ◽  
Peng Zou ◽  
Guowei Zhang ◽  
Xiaomei Dong ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Germ Cells ◽  
Cycle Arrest ◽  
G2 Cell Cycle Arrest ◽  
Dependent Pathway

scholarly journals IMGN779, a CD33-Targeted Antibody-Drug Conjugate (ADC) with a Novel DNA-Alkylating Effector Molecule, Induces DNA Damage, Cell Cycle Arrest, and Apoptosis in AML Cells

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1366-1366 ◽  
Author(s):  
Watkins M Krystal ◽  
Russell Walker ◽  
Nathan Fishkin ◽  
Charlene Audette ◽  
Yelena Kovtun ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Flow Cytometry ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Ex Vivo ◽  
Cytotoxic Agents ◽  
Employment Equity ◽  
Cycle Arrest ◽  
Equity Ownership

Abstract IMGN779 is a CD33-targeting ADC consisting of a humanized anti-CD33 antibody, Z4681A, conjugated to DGN462, a novel DNA-alkylating agent, through a cleavable disulfide linker, sulfo-SPDB. CD33 is broadly expressed on leukemic blasts of patients with AML, making it a promising target for AML therapy. DGN462 is a member of the novel IGN class of DNA-acting cytotoxic agents, that consists of an indolino-benzodiazepine dimer containing a mono-imine moiety. Potent killing of AML tumor cells by DGN462 and IMGN779 has previously been demonstrated in vitro (K. Whiteman et. al, ASH 2014 #2321). Here we describe studies elucidating the mechanism of action of this novel payload in the AML cell lines: MV4-11, HL60, and EOL-1. The ability of DGN462 to alkylate DNA was demonstrated in an AML cell line by isolation and analysis of the genomic DNA from cells. DGN462 was found to co-purify with DNA, demonstrating that it covalently reacts with cellular DNA. A comet assay was performed confirming that DGN462 does not cross-link DNA. H2AX is known to be phosphorylated on serine 139 in response to DNA damage. Using flow cytometry, we assessed the phosphorylation of H2AX in AML cell lines following exposure to DGN462 and IMGN779. Increases in phosphorylated H2AX levels were detected as early as 4 hours following exposure to DGN462-SMe and 12 hours following exposure to IMGN779. Additional flow cytometry analysis showed that exposure to DGN462-SMe and IMGN779 leads to S-phase accumulation, G2/M arrest, followed by induction of apoptotic markers (cleaved PARP and cleaved Caspase-3) at later time points. Ex vivo studies using AML patient samples also showed elevation of phosphorylated H2AX and an increase in apoptosis in myeloid blasts following exposure to DGN462-SMe and IMGN779. As a demonstration of proof-of-mechanism in AML disease models, our results suggest that cell killing by IMGN779 is mediated by DNA damage, as a consequence of DNA alkylation. The DNA damage response is accompanied by cell cycle arrest, which leads to apoptosis. This relationship will be further explored in additional AML preclinical models to support the use of phosphorylated H2AX as a pharmacodynamic biomarker for IMGN779 activity in future clinical studies. Disclosures Krystal: ImmunoGen, Inc.: Employment, Equity Ownership. Walker:ImmunoGen, Inc.: Employment, Equity Ownership. Fishkin:ImmunoGen, Inc.: Employment, Equity Ownership. Audette:ImmunoGen, Inc.: Employment, Equity Ownership. Kovtun:ImmunoGen, Inc.: Employment, Equity Ownership. Romanelli:ImmunoGen, Inc.: Employment, Equity Ownership.

The Capacity of the Hypomethylating Agents Azacytidine and Decitabine to Induce Apoptosis and Cell Cycle Arrest Depends on the Activation of the DNA-Damage Response Pathway.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1655-1655
Author(s):  
Simone Boehrer ◽  
Lionel Ades ◽  
Nicolas Tajeddine ◽  
Lorenzo Galluzzi ◽  
Stephane de Botton ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Dna Damage Response ◽  
Cell Cycle Progression ◽  
Hypomethylating Agents ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Damage Response

Abstract Background: The hypomethylating agents azacytidine (AZA) and decitabine (DEC) have shown clinical efficacy in patients (pts) with MDS. There is in vitro evidence that both agents, in addition to their hypomethylating effect, also function by inducing apoptosis, cell cycle arrest and/or the activation of a DNA damage response (DDR). However, the exact contributions of those mechanisms of action and their functional interdependence remain to be defined. Methods: A panel of MDS (P39, MDS-1)- and AML (HL-60, KG-1)-derived cell lines were incubated with increasing dosages of AZA (1–2μM) and DEC (1–2μM) and the drugs capacity to induce apoptosis (DiOC6(3)/PI), cell cycle arrest (PI) and/or a DDR (immunoflourescence staining of P-ATM, P-Chk-1, P-Chk-2, γ-H2AX) were assessed in absence and presence of the ATM-inhibitor KU-55933 and the Chk-1 inhibitor UCN-01. Results: We show that both drugs induced dose-dependent apoptosis in myeloid cell lines: whereas AZA increased apoptosis in KG-1 and HL-60 by about 10% (48h, 2μM) the respective incubation with DEC augmented apoptosis by about 20% (HL-60) to 30% (KG-1). P39 cells were resistant to AZA and increased apoptosis by 15% after 48h of 2μM DEC, and MDS-1 cells were resistant to both drugs. In addition, both drugs induced a G2/M-arrest in P39 (+15% after 48h with 2μM of AZA or DEC) and HL-60 (+20% after 48h with 2μM of AZA or DEC) cells, but not in KG-1 and MDS-1 cells. Noteworthy, both drugs induced a DDR in the apoptosis-sensitive KG-1 cells (but not P39 cells) as evidenced by the appearance of nuclear P-ATM and γ-H2AX foci. Surprisingly, this activation of P-ATM did not induce the nuclear translocation of P-Chk-1-Ser317 or P-Chk-2-Ser68. To more clearly define the importance of the DDR in AZA- and DEC-induced apoptosis and G2/M-arrest, experiments were recapitulated in the presence of the ATM-inhibitor KU-55933 and the Chk-1 inhibitor UCN-01. Inhibition of ATM abrogated the apoptosis-inducing activity of AZA and DEC in KG-1 cells (without influencing cell cycle progression), whereas inhibition of Chk-1 remained without effect. In contrast, in P39 and HL-60 cells, inhibition of ATM neither affected cell cycle progression, nor sensitivity towards the drugs. Nevertheless, inhibition of Chk-1 by UCN-01 completely abrogated the G2/M-arresting effect of AZA (and diminished that of DEC) in P39 and HL-60 cells. Conclusions: We provide novel evidence for the cell-type dependent capacity of the hypomethylating agents 5-azacytidine and decitabine to induce apoptosis, cell-cycle arrest and DDR in cell lines representing different subtypes of MDS and AML. Moreover, we show the crucial role of ATM and Chk-1 activation – as part of the DDR – in mediating AZA and DEC apoptosis-inducing and cell cycle-arresting effects, respectively, providing evidence that hypomethylating agents confer their beneficial effects by employing different pathways of the DDR.

The DNA Methyltransferase Inhibitor Decitabine Induces DNA Damage, Cell Cycle Arrest and Apoptosis in Multiple Myeloma

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1833-1833
Author(s):  
Ken Maes ◽  
Miguel Lemaire ◽  
Jordan Gauthier ◽  
Hendrik De Raeve ◽  
Eline Menu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Dna Damage Response ◽  
Cycle Arrest ◽  
Phase Arrest ◽  
Damage Response ◽  
M Phase

Abstract Abstract 1833 Multiple myeloma (MM) is still an incurable plasma cell malignancy, thus highlighting the need for alternative treatment options. Currently, strategies for therapy are being developed targeting epigenetic modification using epigenetic modulating agents like histone deacetylase inhibitors (HDACi) and DNA methyltransferase inhibitors (DNMTi). 5-aza-2'-deoxycitidine or decitabine (DAC) is a DNMTi and is FDA approved for treatment of myelodysplastic syndrome and has beneficial clinical effects against leukemia. The anti-tumor effects are ascribed to two non-mutual exclusive modes of action. Relative low doses are thought to lead to passive CpG demethylation resulting in re-expression of genes silence by DNA methylation and apoptosis, while relative high doses are cytotoxic by inducing a DNA damage response together with cell cycle arrest and apoptosis. In multiple myeloma (MM), preclinical data regarding the effects of DAC is, however, limited. Therefore, we investigated the cytotoxic effects of DAC in MM both in vitro and in vivo. In addition, we evaluated the combination of DAC with the pan-HDAC inhibitor JNJ-26481585. First, we assessed the effects of DAC on cell cycle progression and apoptosis on a panel of MM cell lines. We used one murine (5T33MMvt) and 5 human (OPM-2, RPMI 8226, LP-1, KMS-11 and NCI-H929) MM cell lines. In general, DAC could affect cell cycle progression by inducing either a G0/G1-phase arrest or a G2/M-phase arrest. The 5T33MMvt and LP-1 cells were arrested in the G2/M-phase, while OPM-2 and NCI-H929 cells underwent a G0/G1-phase arrest. Subsequently, apoptosis occurred in all cell lines. Interestingly, the 5T33MMvt cells were relatively sensitive, as nM doses of DAC were sufficient to induce massive apoptosis in a relative short incubation time (2 days). The human cell lines were less sensitive since higher doses (μM range) and longer incubation time (3–5 days) were necessary to induce apoptosis, with the OPM-2 cells being the least sensitive. To determine the potential mechanisms more in detail, we focused on the 5T33MMvt and OPM-2 cells. In both cell lines, DAC-mediated apoptosis was associated with caspase activation and PARP cleavage, Bim upregulation and posttranslational changes in Mcl-1 expression. The G2/M-phase arrest in the 5T33MMvt cells was accompanied by phosphorylation of CDK-1 and an increase in cyclinB1 expression. In both cell lines, p27 protein expression was increased, what may contribute to the cell cycle arrest. Furthermore, in the 5T33MMvt cells, a DNA damage response was activated as evidenced by a clear induction of ATM and H2AX phosphorylation. This was not the case for the OPM-2 cells, in which we observed no ATM activation and only a modest H2AX phosphorylation upon DAC treatment. In addition, the tumor suppressor p53 was phosphorylated on ser15 upon DAC treatment in both cell lines, indicating a potential role of p53. However, a p53 inhibitor, pifithrin-α, could not abrogate DAC-induced apoptosis indicating that p53 transactivation is not essential in this process. Next, we used the syngeneic 5T33 murine MM model (5T33MM) to investigate the in vivo effects of DAC. 5T33MM mice were daily treated with 0.1, 0.2 and 0.5 mg/kg DAC. We observed a significant decrease in serum M-protein, bone marrow plasmacytosis and spleno- and hepatomegaly compared to vehicle treated mice. These effects led to a significant increase in survival probability of DAC treated mice (p≤0.001). Lastly, we evaluated the possibility of combining DAC with a pan-HDAC inhibitor JNJ-26481585 (JNJ-585). DAC and JNJ-585 synergistically induced cell death in RPMI-8226, OPM-2 and 5T33MMvt cells. We further demonstrated the combinatory effects of DAC and JNJ-585 in the 5T33MM murine model. Here, we observed enhanced effects of DAC and JNJ-585 on serum M-protein, BM tumor load and survival (p≤0.001) compared to either agent alone. In conclusion, DAC shows potent anti-MM effects both in vitro and in vivo. Mechanistically, we observed induction of a DNA damage response and/or cell cycle arrest. Apoptosis was caspase-mediated but independent of the transactivation of p53. DAC was also efficient in the murine 5T33MM model in which DAC treatment led to a survival benefit. In addition, DAC showed useful in a combination with the HDAC inhibitor JNJ-585. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Orai1 and Stim1 Mediate the Majority of Store-Operated Calcium Entry in Multiple Myeloma and Have Strong Implications for Adverse Prognosis

2018 ◽  
Vol 48 (6) ◽  
pp. 2273-2285 ◽  
Author(s):  
Wei Wang ◽  
Yuyue Ren ◽  
Lianjie Wang ◽  
Weiwei Zhao ◽  
Xiushuai Dong ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Cell Viability ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Annexin V ◽  
Hematologic Malignancies ◽  
Calcium Entry ◽  
Cycle Arrest ◽  
Store Operated Calcium Entry

Background/Aims: Multiple myeloma (MM) is a plasma cell neoplasm which constitutes about 10% of all hematologic malignancies. Despite the development and application of novel agents, MM still undergoes an aggressive and incurable course in the vast majority of patients. Ca2+ is one of the critical regulators of cell migration. Ca2+ influx is essential for the migration of various types of cells including tumor cells. However, the role of store-operated calcium entry (SOC) channels, the only Ca2+ channels of non-excitable cells, has not yet been reported in MM cell survival. Methods: We evaluated the expression of Stim1 and Orai1 (two key regulators of SOC) in MM tissues and cell lines by immunohistochemical assay, quantitative real-time PCR assay and western blot. MM cell lines were pretreated with pharmacological blockers and siRNAs, and then MM cell proliferation, cell cycle arrest, and apoptosis were examined by FACS (flow cytometry) assay, and Annexin V-FITC/PI staining. The correlation between the expression of Stim1 (or Orai1) level and outcome in MM were assessed by using Progress Free Survival (PFS). Results: Stim1 and Orai1 were both abundantly expressed in MM tissue and MM cell lines. Inhibition of SOCE reduced MM cell viability, and induced cell cycle arrest and apoptosis. Stim1 or Orai1 silencing also reduced cell viability, caused cell apoptosis and cell cycle arrest in MM cell lines. Over-expression of Stim1/Orai1 in MM patients was closely associated with the clinical outcome of MM. Conclusion: The Stim1/Orai1-mediated signaling participates in the pathogenesis of MM, which represents an attractive target for future therapeutic intervention.

scholarly journals NRF2 preserves genomic integrity by facilitating ATR activation and G2 cell cycle arrest

2020 ◽  
Vol 48 (16) ◽  
pp. 9109-9123 ◽  
Author(s):  
Xiaohui Sun ◽  
Yan Wang ◽  
Kaihua Ji ◽  
Yang Liu ◽  
Yangyang Kong ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Cellular Response ◽  
Genome Stability ◽  
Related Factor ◽  
Dna Double Strand Breaks ◽  
Ros Scavenging ◽  
Cycle Arrest ◽  
G2 Cell Cycle Arrest

Abstract Nuclear factor erythroid 2-related factor 2 (NRF2) is a well-characterized transcription factor that protects cells against oxidative and electrophilic stresses. Emerging evidence has suggested that NRF2 protects cells against DNA damage by mechanisms other than antioxidation, yet the mechanism remains poorly understood. Here, we demonstrate that knockout of NRF2 in cells results in hypersensitivity to ionizing radiation (IR) in the presence or absence of reactive oxygen species (ROS). Under ROS scavenging conditions, induction of DNA double-strand breaks (DSBs) increases the NRF2 protein level and recruits NRF2 to DNA damage sites where it interacts with ATR, resulting in activation of the ATR–CHK1–CDC2 signaling pathway. In turn, this leads to G2 cell cycle arrest and the promotion of homologous recombination repair of DSBs, thereby preserving genome stability. The inhibition of NRF2 by brusatol increased the radiosensitivity of tumor cells in xenografts by perturbing ATR and CHK1 activation. Collectively, our results reveal a novel function of NRF2 as an ATR activator in the regulation of the cellular response to DSBs. This shift in perspective should help furnish a more complete understanding of the function of NRF2 and the DNA damage response.

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