Role of mitogen-activated protein kinase in Zn-BC-AM PDT-induced apoptosis in nasopharyngeal carcinoma cells

Cell Biochem Funct. 2010 Apr;28(3):239-48. doi: 10.1002/cbf.1650.


Photodynamic therapy (PDT) with a recently developed photosensitizer Zn-BC-AM was found to effectively induce apoptosis in a well-differentiated nasopharyngeal carcinoma (NPC) HK-1 cell line. Sustained activation of p38 mitogen-activated protein kinase (MAPK) and c-jun N-terminal kinase (JNK) as well as a transient increase in activation of extracellular signal-regulated kinase (ERK) were observed immediately after Zn-BC-AM PDT. A commonly used p38 MAPK/JNK pharmacological inhibitor PD169316 was found to reduce PDT-induced apoptosis of HK-1 cells. PD169316 also prevented the loss of Bcl-2 and Bcl-xL in PDT-treated HK-1 cells. However, inhibition of JNK with SP600125 had no effect on Zn-BC-AM PDT-induced apoptosis while inhibition of ERK with PD98059 or p38 MAPK with SB203580 significantly increased Zn-BC-AM PDT-induced apoptosis. Further study showed that knockdown of the p38beta isoform with siRNA also increased Zn-BC-AM PDT-induced apoptosis, indicating that the anti-apoptotic effect of PD169316 in PDT-treated HK-1 cells was probably independent of p38 MAPK or JNK activation. Taken together, the results suggest that inhibition of p38beta and ERK may enhance the therapeutic efficacy of Zn-BC-AM PDT on NPC cells. It should be noted that data only based on the use of PD169316 should be interpreted in caution.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects*
  • Cell Line, Tumor
  • Enzyme Activation
  • Enzyme Inhibitors / metabolism
  • Extracellular Signal-Regulated MAP Kinases / genetics
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Humans
  • JNK Mitogen-Activated Protein Kinases / antagonists & inhibitors
  • JNK Mitogen-Activated Protein Kinases / genetics
  • JNK Mitogen-Activated Protein Kinases / metabolism*
  • Metalloporphyrins / pharmacology*
  • Nasopharyngeal Neoplasms* / drug therapy
  • Nasopharyngeal Neoplasms* / enzymology
  • Nasopharyngeal Neoplasms* / pathology
  • Photochemotherapy / methods*
  • Photosensitizing Agents / pharmacology*
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • p38 Mitogen-Activated Protein Kinases / antagonists & inhibitors
  • p38 Mitogen-Activated Protein Kinases / genetics
  • p38 Mitogen-Activated Protein Kinases / metabolism*


  • Enzyme Inhibitors
  • Metalloporphyrins
  • Photosensitizing Agents
  • Proto-Oncogene Proteins c-bcl-2
  • RNA, Small Interfering
  • Zn-BC-AM
  • Extracellular Signal-Regulated MAP Kinases
  • JNK Mitogen-Activated Protein Kinases
  • p38 Mitogen-Activated Protein Kinases