Polypeptide antibiotic actinomycin D induces Mcl-1 uncanonical downregulation in lung cancer cell apoptosis

Chia Ling Chen, Po Chun Tseng, Yen Po Chao, Ting Jing Shen, Ming Kai Jhan, Yung Ting Wang, Thi Thuy Nguyen, Chiou Feng Lin

Research output: Contribution to journalArticlepeer-review


Aims: Actinomycin (Act) D, a polypeptide antibiotic, is used clinically to inhibit the growth of malignant tumors. Act D binds to DNA at the transcription initiation complex to prevent the elongation of RNA. Act D causes DNA damage, growth inhibition, and cell death. Myeloid cell leukemia (Mcl-1) is an anti-apoptotic Bcl-2 family member protein, and the present study explored the effects and molecular mechanism of Act D-induced Mcl-1 downregulation. Main methods: Human adenocarcinoma A549 cells were used to check the cytotoxic signaling pathways of Act D, particularly in apoptotic mechanism, in a cell-based study approach. Specific blockers targeting the apoptotic factors were examined for their possible roles. Key findings: We found that Act D caused cell growth inhibition and apoptosis. Propidium iodide-based flow cytometric analysis and immunostaining confirmed cell apoptosis. Treatment with Act D caused DNA damage, followed by p53-independent cell death. Western blotting showed a significant decrease in Mcl-1 expression, mitochondrial transmembrane potential loss, and caspase-9/caspase-3 cascade activation. The proteasome inhibitor MG132 reversed Act D-induced Mcl-1 downregulation. However, pharmacological inhibition of glycogen synthase kinase-3, p53 expression, ER stress, autophagy, and vesicle acidification, which are Mcl-1-regulating signaling pathways, did not rescue these effects. Notably, Cullin-Ring E3 ligase partially mediated Mcl-1 downregulation. Administration of transforming growth factor-β induced mesenchymal cell differentiation, but Act D still decreased Mcl-1 and caused cell apoptosis. Significance: All of these data show a potential pro-apoptotic effect for Act D by facilitating Mcl-1 uncanonical downregulation.

Original languageEnglish
Article number121615
JournalLife Sciences
Publication statusPublished - May 2023


  • Actinomycin D
  • Cell apoptosis
  • Lung cancer cell
  • Mcl-1
  • Transforming growth factor-β

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)


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