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EM011 activates a survivin-dependent apoptotic program in human non-small cell lung cancer cells
Prasanthi Karna1, Starlette M Sharp, Clayton Yates
1Department of Biology, Georgia State University, Atlanta, GA-30303, USA. pkarna@gsu.edu
Background:
Lung cancer remains a leading cause of cancer death among both men and women in the United States. Treatment modalities available for this malignancy are inadequate and thus new drugs with improved pharmacological profiles and superior therapeutic indices are being continually explored. Noscapinoids constitute an emerging class of anticancer agents that bind tubulin but do not significantly alter the monomer/polymer ratio of tubulin. EM011, a rationally-designed member of this class of non-toxic agents, is more potent than the lead molecule, noscapine.
Results:
Here we report that EM011 inhibited proliferation of a comprehensive panel of lung cancer cells with IC(50)'s ranging from 4-50 microM. In A549 human non-small cell lung cancer cells, the antiproliferative activity was mediated through blockage of cell-cycle progression by induction of a transient but robust mitotic arrest accompanied by activation of the spindle assembly checkpoint. The mitotically-arrested A549 cells then override the activated mitotic checkpoint and aberrantly exit mitosis without cytokinesis resulting in pseudo G1-like multinucleated cells that either succumb directly to apoptosis or continue another round of the cell-cycle. The accumulated enormous DNA perhaps acts as genotoxic stress to trigger cell death. EM011-induced apoptotic cell death in A549 cells was associated with a decrease of the Bcl2/BAX ratio, activation of caspase-3 and cleavage of PARP. Furthermore, EM011 induced downregulation of survivin expression over time of treatment. Abrogation of survivin led to an increase of cell death whereas, overexpression caused decreased apoptosis.
Conclusion:
These in vitro data suggest that EM011 mediates antiproliferative and proapoptotic activity in non-small cell A549 lung cancer cells by impeding cell-cycle progression and attenuating antiapoptotic signaling circuitries (viz. Bcl2, survivin). The study provides evidence for the potential usefulness of EM011 in chemotherapy of lung cancer.
Insights
EM011, a novel noscapinoid, effectively inhibits lung cancer cell proliferation and induces apoptosis by disrupting cell-cycle progression and downregulating anti-apoptotic proteins like survivin.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Lung cancer is a leading cause of cancer-related mortality in the US.
- Current lung cancer treatments are insufficient, necessitating the development of novel therapeutic agents.
- Noscapinoids, a class of tubulin-binding agents, are being explored for their anticancer potential, with EM011 showing enhanced potency over noscapine.
Purpose of the Study:
- To investigate the antiproliferative and proapoptotic effects of EM011 in lung cancer cells.
- To elucidate the underlying mechanisms of EM011's action, including cell-cycle effects and modulation of apoptotic pathways.
Main Methods:
- EM011's efficacy was tested against a panel of lung cancer cell lines.
- Cell-cycle progression, mitotic arrest, and apoptosis were analyzed in A549 non-small cell lung cancer cells.
- Changes in Bcl2/BAX ratio, caspase-3 activation, PARP cleavage, and survivin expression were assessed.
Main Results:
- EM011 demonstrated potent antiproliferative activity against lung cancer cells (IC50s 4-50 microM).
- In A549 cells, EM011 induced mitotic arrest, aberrant cell division, and apoptosis.
- EM011 treatment led to decreased Bcl2/BAX ratio, caspase-3 activation, PARP cleavage, and reduced survivin expression.
Conclusions:
- EM011 exhibits significant antiproliferative and proapoptotic effects in non-small cell lung cancer cells.
- The drug functions by disrupting cell-cycle progression and inhibiting key anti-apoptotic signaling pathways.
- EM011 shows promise as a potential chemotherapeutic agent for lung cancer treatment.
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