Varied expression and localization of multiple galectins in different cancer cell lines

  • Authors:
    • Arun Satelli
    • Prema S. Rao
    • Prem K. Gupta
    • Paul R. Lockman
    • Kalkunte S. Srivenugopal
    • U. Subrahmanyeswara Rao
  • View Affiliations

  • Published online on: Saturday, March 1, 2008
  • Pages:587-594 DOI: 10.3892/or.19.3.587
0

Abstract

Galectins play a key role in oncogenic processes. Although several galectins are known, their relative expression at the mRNA and protein levels, the subcellular localization, and their relationship to the oncogenic manifestation remains unclear. Herein we report a comprehensive characterization of the expression of major galectins in human breast cancer (drug-sensitive MCF-7 and drug-resistant MCF-7/AdrR), colon cancer (HCT-116 and HT-29), and glioma (T98G) cell lines, as these cells are common model systems for studying oncogenic processes. The expected ≈14.5 kDa galectin-1, predominantly cytosolic, was detected in the cancer and normal cell lines. Notably, two different molecular forms of galectin-1 with molecular masses of ≈13.5 and 15 kDa were detected in T98G cells, the latter being in the extracellular medium, perhaps a result of post-translational processing. Immunocytochemistry indicated that the extracellular galectin-1 bound to the cell surface was punctated in appearance, suggesting that it was bound to specific receptors. Immunohistological studies indicated that metastasizing carcinomas express high levels of galectin-1. On the other hand, galectin-3 was readily detectable in all cancer cell lines but undetectable in normal cell lines, indicating that galectin-3 is a cancer-specific biomarker protein. Galectin-3 was a cytosolic protein but was not detected in the extracellular medium, indicating that cancer cells do not secrete this galectin. Finally, despite the RT-PCR analysis suggesting the presence of two transcripts of galectin-8 in all cancer cell lines, the corresponding ≈36 kDa protein was only detectable in the nuclear and cytosolic fractions upon cell fractionation. Notably, a different molecular form of galectin-8 of ≈18 kDa was immunoprecipitated from the extracellular media, suggesting that the secreted galectin-8 undergoes post-translational processing. These results highlight the expression of galectins in different molecular forms in cancers, warranting caution in interpreting the results of functional studies of individual galectins, particularly because these proteins function redundantly in cancer pathways.

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March 2008
Volume 19 Issue 3

Print ISSN: 1021-335X
Online ISSN:1791-2431

2015 Impact Factor: 2.486
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APA
Satelli, A., Rao, P.S., Gupta, P.K., Lockman, P.R., Srivenugopal, K.S., & Rao, U.S. (2008). Varied expression and localization of multiple galectins in different cancer cell lines. Oncology Reports, 19, 587-594. http://dx.doi.org/10.3892/or.19.3.587
MLA
Satelli, A., Rao, P. S., Gupta, P. K., Lockman, P. R., Srivenugopal, K. S., Rao, U. S."Varied expression and localization of multiple galectins in different cancer cell lines". Oncology Reports 19.3 (2008): 587-594.
Chicago
Satelli, A., Rao, P. S., Gupta, P. K., Lockman, P. R., Srivenugopal, K. S., Rao, U. S."Varied expression and localization of multiple galectins in different cancer cell lines". Oncology Reports 19, no. 3 (2008): 587-594. http://dx.doi.org/10.3892/or.19.3.587