Effect of miR-128 in DNA damage of HL-60 acute myeloid leukemia cells
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Published on: September 5, 2017
Hugo Seca, Raquel T Lima, Gabriela M Almeida
1Cancer Drug Resistance Group, IPATIMUP, Rua Dr Roberto Frias, s/n 4200-465 Porto, Portugal. hvasconcelos@ipatimup.pt.
Abstract:
miR-128 has been associated with cancer, particularly with leukemia. In particular, this miR has been described, together with other miRs, to allow the discrimination between AML (acute myeloid leukemia) and ALL (acute lymphoblastic leukemia). In addition, miR-128 is included in miR signatures which not only allow characterizing a particular subtype of AML but are also associated with worse clinical outcome in a subgroup of patients with high-risk molecular features of AML. Nevertheless, all the published studies are based on data from expression arrays and no functional studies have been performed. Therefore, in order to further understand the role of miR-128 in AML cells and in their response to some chemotherapy, overexpression of miR-128 was achieved with miR-mimics in an AML cell line (HL-60). This resulted in decreased cellular viability and increased sensitization to both etoposide and doxorubicin. Overexpression of miR-128 increased programmed cell death but had no effect on cell cycle profile, 1 apoptosis or autophagy, as no alterations were observed in the protein levels of PARP, pro-caspase-3, Vps34, Beclin-1 or LC3-II. In addition, miR-128 overexpression increased the levels of DNA damage, as could be concluded by an increase in the comet's tail intensity in the comet assay, an increase in the number of DNA repair foci stained with either γ-H2AX or 53BP1 proteins, and an increase in the levels of these two proteins (observed by Western blot). To the best of our knowledge, this is the first association of miR-128 with DNA damage in a leukemia context.
Insights
MicroRNA-128 (miR-128) overexpression in acute myeloid leukemia (AML) cells reduces viability and sensitizes them to chemotherapy. This study is the first to link miR-128 to increased DNA damage in leukemia.
Area of Science:
- Molecular Biology
- Oncology
- Biochemistry
Background:
- MicroRNA-128 (miR-128) is implicated in various cancers, including leukemia.
- Existing studies on miR-128 in acute myeloid leukemia (AML) rely on expression arrays, lacking functional validation.
- miR-128 is part of signatures that characterize AML subtypes and predict poor outcomes in high-risk patients.
Purpose of the Study:
- To investigate the functional role of miR-128 in AML cells.
- To determine the effect of miR-128 overexpression on AML cell viability and response to chemotherapy.
- To explore the impact of miR-128 on DNA damage, apoptosis, autophagy, and cell cycle progression in AML.
Main Methods:
- Overexpression of miR-128 using miR-mimics in the HL-60 AML cell line.
- Assessment of cellular viability, chemosensitization to etoposide and doxorubicin.
- Analysis of programmed cell death, apoptosis, autophagy, and cell cycle.
- Comet assay and Western blot to evaluate DNA damage and repair foci (γ-H2AX, 53BP1).
Main Results:
- miR-128 overexpression decreased HL-60 cell viability and increased sensitivity to etoposide and doxorubicin.
- Programmed cell death was enhanced, with no significant changes in apoptosis, autophagy, or cell cycle.
- Increased DNA damage was observed, evidenced by comet assay and elevated levels of DNA repair proteins γ-H2AX and 53BP1.
Conclusions:
- miR-128 plays a functional role in AML by reducing cell viability and enhancing chemotherapy response.
- miR-128 overexpression induces DNA damage in AML cells, a novel finding in the context of leukemia.
- These findings highlight miR-128 as a potential therapeutic target or biomarker in AML treatment strategies.
