Antiproliferative effects of lactic acid via the induction of apoptosis and cell cycle arrest in a human keratinocyte cell line (HaCaT)

J Dermatol Sci. 2009 Jun;54(3):175-84. doi: 10.1016/j.jdermsci.2009.02.012. Epub 2009 Mar 31.


Background: Alpha-hydroxy acids (AHAs) have been widely used in cosmetic industry. However, knowledge on cytotoxicity of AHAs in human keratinocytes is limited.

Objective: Lactic acid (LA) is one of the most commonly used AHAs in skin care and peeling formulations. We investigated the antiproliferative effects of LA in a human keratinocyte cell line (HaCaT).

Methods: HaCaT cells were treated with LA at 7.5 approximately 17.5mM for various time periods. The molecular mechanisms of anti-proliferation through cell cycle arrest and apoptosis were investigated by 4,6-diamidino-2-phenylindole dihydrochloride (DAPI) stain, flow cytometry, Western blot and confocal microscopy.

Results: Viability of HaCaT cells decreased on exposure to LA. Flow cytometry showed apoptosis was closely related to the increase of reactive oxygen species (ROS) and calcium release, and to the decline of mitochondrial membrane potential (MMP). Western blotting showed an increase in the levels of P21, P27 and a decrease in the levels of Cyclin E, Cyclin A, and CDK 2, indicating cell cycle arrest at G1/S. The occurrence of apoptosis was proved by the increased expressions of Fas, Bax, caspase-3, -8, and -9, apoptosis-inducing factor (AIF), and endonuclease G (EndoG), and the declined expressions of Bcl-2 and Bcl-xL. In addition, the intracytosolic release of AIF, EndoG, and cytochrome c contributing to the occurrence of apoptosis was demonstrated by confocal microscopy.

Conclusion: We demonstrated that LA had antiproliferative effect in HaCaT cell through the inhibition of cell cycle progression at G1/S, and the induction of programmed cell death through caspase-dependent and caspase-independent pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Chloromethyl Ketones / pharmacology
  • Apoptosis Regulatory Proteins / metabolism
  • Apoptosis*
  • Calcium / metabolism
  • Caspase 3 / drug effects
  • Caspase 3 / metabolism
  • Cell Cycle / drug effects*
  • Cell Cycle / physiology
  • Cell Line
  • Cell Proliferation / drug effects*
  • Cell Survival / drug effects
  • Cell Survival / physiology
  • Cysteine Proteinase Inhibitors / pharmacology
  • Cytochromes c / drug effects
  • Cytochromes c / metabolism
  • Cytostatic Agents / pharmacology*
  • Endodeoxyribonucleases / drug effects
  • Endodeoxyribonucleases / metabolism
  • Humans
  • Keratinocytes / drug effects*
  • Keratinocytes / metabolism
  • Lactic Acid / pharmacology*
  • Membrane Potential, Mitochondrial / drug effects
  • Membrane Potential, Mitochondrial / physiology
  • Reactive Oxygen Species / metabolism


  • Amino Acid Chloromethyl Ketones
  • Apoptosis Regulatory Proteins
  • Cysteine Proteinase Inhibitors
  • Cytostatic Agents
  • Reactive Oxygen Species
  • benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
  • Lactic Acid
  • Cytochromes c
  • Endodeoxyribonucleases
  • endonuclease G
  • Caspase 3
  • Calcium