Involvement of PKC-iota in glioma proliferation

Cell Prolif. 2008 Feb;41(1):122-35. doi: 10.1111/j.1365-2184.2007.00506.x.

Abstract

Atypical protein kinase C-iota (PKC-iota) protects cells against apoptosis and may play a role in cell proliferation. However, in vivo, the status and function of PKC-iota in human normal brain tissue, gliomas, benign and malignant meningiomas as well as its in vitro status in proliferating and confluent glioma cells, remains unknown.

Objectives: The objectives of our research were to determine whether expression of PKC-iota is altered either in gliomas or in benign and malignant meningiomas, compared to normal brain. In addition, we wished to establish the expression of PKC-iota in proliferating plus in cell cycle-arrested glioma cell lines, as well as the relationship between PKC-iota siRNA on PKC-iota protein content and cell proliferation.

Materials and methods: Western blot analyses for PKC-iota were performed on 12 normal brain biopsies, 15 benign meningiomas, three malignant meningiomas and three gliomas.

Results: Results demonstrated no (n = 9) or very weak (n = 3) detection of PKC-iota in normal brain tissue. In comparison, PKC-iota was robustly present in the majority of the benign meningiomas. Similarly, PKC-iota was abundant in all malignant meningiomas and gliomas. Western blotting for PKC-iota in confluent or proliferating glioma cell lines depicted substantial quantities of PKC-iota in proliferating T98G and U-138MG glioma cells. In contrast, confluent cells had either 71% (T98G) or 21% (U-138MG) less PKC-iota than proliferating cells. T98 and U-138 MG glioma cells treated with 100 nm PKC-iota siRNA had lower levels of cell proliferation compared to control siRNA-A and complete down-regulation of PKC-iota protein content.

Conclusion: These results support the concept that presence of PKC-iota may be required for cell proliferation to take place.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Base Sequence
  • Brain Neoplasms / enzymology
  • Brain Neoplasms / pathology*
  • Cell Line, Tumor
  • Cell Proliferation
  • Flow Cytometry
  • Glioma / enzymology
  • Glioma / pathology*
  • Humans
  • Isoenzymes / metabolism*
  • Protein Kinase C / metabolism*
  • RNA, Small Interfering

Substances

  • Isoenzymes
  • RNA, Small Interfering
  • Protein Kinase C
  • protein kinase C lambda