Contributions
Abstract: PB1612
Type: Publication Only
Background
DNA damage repair pathways greatly affect the response to genotoxic drugs in cancer cells, so inhibition of such pathways could be a potentially useful strategy to enhance chemosensitivity. DNA-dependent protein kinase (DNA-PK) plays a crucial role in the repair of DNA double-strand breaks (DSBs) that are probably one of the most detrimental types of DNA damage. It has been shown that DNA-PK is highly expressed in B-cell precursor acute lymphoblastic leukemia (BCP-ALL) cells. Less well appreciated was the effect of DNA-PK inhibition on sensitivity of BCP-ALL cells to DNA-damaging agents.
Aims
Disruptions in DNA repair system is a way to induce cell death. So, we determine to evaluate the effect of DNA-PK inhibition on sensitivity of BCP-ALL cells to DNA-damaging agents. In the present study, we investigated the effects of DNA-PK inhibitor (NU7441) on doxorubicin-induced DSBs in BCP-ALL cells.
Methods
NALM-6 and SUP-B15 cells (BCP-ALL cell lines) were treated with doxorubicin in presence or absence of different concentration of DNA-PK inhibitor (NU7441). The apoptosis was assessed using Annexin V-PI staining followed by flow cytometry analysis. Phosphorylated H2AX was detected by immunofluorescence staining. The expression levels of a repertoire of apoptotic and anti-apoptotic proteins were assessed by western blot analysis. qRT-PCR were used to evaluate the gene expression levels.
Results
Here, we show that the DNA-PK inhibitor NU7441 increased doxorubicin-induced apoptosis in BCP-ALL cell lines, correlating with a reduction in DSB repair measured by γ-H2AX foci. NU7441 affected the cell cycle distribution and the cell cycle regulatory molecules in combination with doxorubicin treatment. Doxorubicin-induced DNA-PK phosphorylation was decreased in the presence of NU7441. Apoptosis induction by the combined treatment was associated with marked reduction of Bcl-2 and survivin and a significant increase of Bax mRNA expression levels.
Conclusion
our data indicate that inhibition of DNA-PK might be an effective approach to enhance the tumor-cell-killing effects of DNA-damaging agents such as doxorubicin in BCP-ALL and may deliver novel, targeted therapy into the clinic.
Session topic: 1. Acute lymphoblastic leukemia – Biology & Translational Research
Keyword(s): Acute lymphoblastic leukemia, DNA Damage, DNA repair
Abstract: PB1612
Type: Publication Only
Background
DNA damage repair pathways greatly affect the response to genotoxic drugs in cancer cells, so inhibition of such pathways could be a potentially useful strategy to enhance chemosensitivity. DNA-dependent protein kinase (DNA-PK) plays a crucial role in the repair of DNA double-strand breaks (DSBs) that are probably one of the most detrimental types of DNA damage. It has been shown that DNA-PK is highly expressed in B-cell precursor acute lymphoblastic leukemia (BCP-ALL) cells. Less well appreciated was the effect of DNA-PK inhibition on sensitivity of BCP-ALL cells to DNA-damaging agents.
Aims
Disruptions in DNA repair system is a way to induce cell death. So, we determine to evaluate the effect of DNA-PK inhibition on sensitivity of BCP-ALL cells to DNA-damaging agents. In the present study, we investigated the effects of DNA-PK inhibitor (NU7441) on doxorubicin-induced DSBs in BCP-ALL cells.
Methods
NALM-6 and SUP-B15 cells (BCP-ALL cell lines) were treated with doxorubicin in presence or absence of different concentration of DNA-PK inhibitor (NU7441). The apoptosis was assessed using Annexin V-PI staining followed by flow cytometry analysis. Phosphorylated H2AX was detected by immunofluorescence staining. The expression levels of a repertoire of apoptotic and anti-apoptotic proteins were assessed by western blot analysis. qRT-PCR were used to evaluate the gene expression levels.
Results
Here, we show that the DNA-PK inhibitor NU7441 increased doxorubicin-induced apoptosis in BCP-ALL cell lines, correlating with a reduction in DSB repair measured by γ-H2AX foci. NU7441 affected the cell cycle distribution and the cell cycle regulatory molecules in combination with doxorubicin treatment. Doxorubicin-induced DNA-PK phosphorylation was decreased in the presence of NU7441. Apoptosis induction by the combined treatment was associated with marked reduction of Bcl-2 and survivin and a significant increase of Bax mRNA expression levels.
Conclusion
our data indicate that inhibition of DNA-PK might be an effective approach to enhance the tumor-cell-killing effects of DNA-damaging agents such as doxorubicin in BCP-ALL and may deliver novel, targeted therapy into the clinic.
Session topic: 1. Acute lymphoblastic leukemia – Biology & Translational Research
Keyword(s): Acute lymphoblastic leukemia, DNA Damage, DNA repair