Antineoplaston induces G(1) arrest by PKCalpha and MAPK pathway in SKBR-3 breast cancer cells

Oncol Rep. 2005 Aug;14(2):489-94.

Abstract

Antineoplastons such as A10 include naturally occurring peptides and amino acid derivatives that control the neoplastic growth of cells. The mechanism underlying this antitumor effect was investigated using the breast cancer cell line, SKRB-3. Cells treated with A10 were monitored for any changes in cell cycle, expression of protein kinase C (PKC), or intracellular signal transduction, particularly phos-phorylation of mitogen-activated protein kinase (MAPK). The A10 markedly inhibited SKBR-3 proliferation due to arrest in the G(1) phase. A10 down-regulated the expression of PKCalpha protein, resulting in inhibition of extracellular signal-regulated kinase (ERK) MAPK phosphorylation. This increased the expression of p16 and p21 protein, with resultant inhibition of Rb phosphorylation, leading to G(1) arrest. This study has defined a pathway in which A10 arrested SKBR-3 cells in the G(1) phase via PKCalpha and MAPK. Our findings indicate that the antineoplaston A10 antitumor effect could be utilized as an effective therapy for breast cancer patients.

Publication types

  • Comparative Study

MeSH terms

  • Benzeneacetamides / pharmacology*
  • Blotting, Western
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology
  • Carbazoles / pharmacology
  • Cell Cycle Proteins / metabolism
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cyclin-Dependent Kinase Inhibitor p16 / metabolism
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclin-Dependent Kinase Inhibitor p27
  • Cyclins / metabolism
  • Dose-Response Relationship, Drug
  • Enzyme Inhibitors / pharmacology
  • Flow Cytometry
  • G1 Phase / drug effects*
  • Humans
  • Indoles / pharmacology
  • Isoenzymes / antagonists & inhibitors
  • Isoenzymes / metabolism
  • MAP Kinase Signaling System / drug effects*
  • Mitogen-Activated Protein Kinases / metabolism*
  • Phosphorylation / drug effects
  • Piperidones / pharmacology*
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / metabolism*
  • Protein Kinase C-alpha
  • Retinoblastoma Protein / metabolism
  • Time Factors
  • Tumor Suppressor Proteins / metabolism

Substances

  • Benzeneacetamides
  • CDKN1A protein, human
  • Carbazoles
  • Cell Cycle Proteins
  • Cyclin-Dependent Kinase Inhibitor p16
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins
  • Enzyme Inhibitors
  • Indoles
  • Isoenzymes
  • Piperidones
  • Retinoblastoma Protein
  • Tumor Suppressor Proteins
  • Go 6976
  • Cyclin-Dependent Kinase Inhibitor p27
  • antineoplaston A10
  • PRKCA protein, human
  • Protein Kinase C
  • Protein Kinase C-alpha
  • Mitogen-Activated Protein Kinases