Crocodile blood extract induces the apoptosis of lung cancer cells through PTEN activity

Oncol Rep. 2016 Sep;36(3):1457-66. doi: 10.3892/or.2016.4914. Epub 2016 Jul 5.


Current treatment strategies for lung cancer cause undesirable side‑effects. Integrated medicine with a curative approach has become a common approach to the treatment strategy. Recent studies suggest that American alligator blood is effective in reducing colorectal cancer cell viability in vitro, but the mechanism remains unclear. In the present study, we aimed to study the anticancer activity of crocodile blood extracts on lung cancer cell line A549 and investigate the possible mechanisms involved. In vitro studies were utilized to investigate the effects on the cancer cells after incubation with the blood extracts. The active fraction that showed more efficacy in inhibiting cell growth was characterized in the supernatant (S2) from whole blood extracts. High performance liquid chromatography (HPLC) analysis revealed that S2 contained more polar moiety from whole blood. S2 induced DNA fragmentation. Cell cycle arrest in the G1/M phase was demonstrated and mitochondrial membrane permeability was disrupted. An increase in the generation of reactive oxygen species (ROS) and increased activities of caspase-3 and caspase-7 were detected. Furthermore, release of cytochrome c, upregulation of expression of Bax, p53, p21, Bid, cleaved forms of the caspase family and PARP along with downregulation of Bcl-2, PCNA, MDM2, caspase‑8, wild types of caspase family proteins and PARP were recorded after treatment with S2 fractions. Moreover, the PI3K/AKT survival pathway was downregulated by S2 fractions in the lung cancer cell line.

MeSH terms

  • A549 Cells
  • Alligators and Crocodiles / blood*
  • Animals
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects*
  • Biological Factors / pharmacology*
  • Caspases / metabolism
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cytochromes c / metabolism
  • Down-Regulation / drug effects
  • G1 Phase Cell Cycle Checkpoints / drug effects
  • Humans
  • Lung Neoplasms / drug therapy*
  • Lung Neoplasms / genetics
  • Lung Neoplasms / metabolism
  • M Phase Cell Cycle Checkpoints / drug effects
  • Membrane Potential, Mitochondrial / drug effects
  • PTEN Phosphohydrolase / genetics*
  • Reactive Oxygen Species / metabolism
  • Signal Transduction / drug effects
  • Up-Regulation / drug effects


  • Antineoplastic Agents
  • Biological Factors
  • Reactive Oxygen Species
  • Cytochromes c
  • PTEN Phosphohydrolase
  • PTEN protein, human
  • Caspases