An association between high Ly-6A/E expression on tumor cells and a highly malignant phenotype

Int J Cancer. 1994 Dec 1;59(5):684-91. doi: 10.1002/ijc.2910590517.


Murine Ly-6 is a molecule expressed by various cells, including several types of hematopoietic cells such as pluripotent stem cells, and activated T cells. Ly-6 is also expressed on tumor cells originating from a variety of tissues. Preliminary observations suggested that the expression of Ly-6A/E is up-regulated on highly tumorigenic variants of polyoma-virus(PyV)-transformed BALB/c 3T3 cells as compared with weakly tumorigenic variants. On the basis of these observations, we sorted PyV-transformed A3C cells or DA3 mammary adenocarcinoma cells into stable sub-populations expressing high or low levels of membrane or mRNA Ly-6A/E. In vivo studies indicated that the high-Ly-6A/E-expressing cells in both tumor systems expressed a considerably more malignant phenotype (higher efficiency in local tumor production as well as in lung colonization) than low-Ly-6A/E expressors. Since the high-Ly-6A/E expressors did not exhibit any growth advantage in vitro over low Ly-6A/E expressors, we concluded that interactions of the former cells with micro-environmental factors operating in vivo (e.g., Ly-6A/E ligands) conferred upon these cells a highly malignant phenotype. Apart from the difference in Ly-6A/E expression, no other phenotypic characteristics distinguished highly from weakly malignant tumor cells. Similarly to T cells, where antibodies to Ly-6 transduce (or co-transduce) a proliferative signal, antibodies to Ly-6A/E were found to transduce a mitogenic signal to high-Ly-6A/E-expressing tumor cells but not to low-Ly-6A/E expressors. Taken together, these results show that Ly-6A/E expression is directly or indirectly associated in vivo with a highly malignant phenotype of 2 types of non-lymphoid murine tumors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Animals
  • Antigens, Ly / analysis*
  • Antigens, Ly / genetics
  • Base Sequence
  • Cell Line, Transformed
  • Gene Expression
  • Lung Neoplasms / etiology
  • Lung Neoplasms / pathology
  • Mammary Neoplasms, Experimental
  • Membrane Proteins / analysis*
  • Membrane Proteins / genetics
  • Mice
  • Mice, Inbred BALB C
  • Molecular Sequence Data
  • Neoplasm Transplantation
  • Neoplasms, Experimental / chemistry*
  • Phenotype*
  • RNA, Messenger / analysis
  • Rats
  • Tumor Cells, Cultured


  • Antigens, Ly
  • Ly6a protein, mouse
  • Membrane Proteins
  • RNA, Messenger