Trichosanthin enhances anti-tumor immune response in a murine Lewis lung cancer model by boosting the interaction between TSLC1 and CRTAM

Cell Mol Immunol. 2011 Jul;8(4):359-67. doi: 10.1038/cmi.2011.12. Epub 2011 May 16.


Trichosanthin (TCS), extracted from the Chinese medicinal herb Trichosanthes kirilowi, has shown promise for the inhibition of tumor growth. However, its immunomodulatory effect on tumor-host interaction remains unknown. In this study, we focused on the effect of TCS on murine anti-tumor immune response in the 3LL Lewis lung carcinoma tumor model and explored the possible molecular pathways involved. In addition to inhibiting cell proliferation and inducing apoptosis in the 3LL tumor, TCS retarded tumor growth and prolonged mouse survival more significantly in C57BL/6 immunocompetent mice than in nude mice. This reflected the fact that the host immune system was involved in tumor eradication. Using FACS analysis, we found that TCS increased the percentage of effector T cells, particularly Interferon-gamma (IFN-γ) producing CD4(+) and CD8(+) T cells from tumor-bearing mice. TCS also promoted the vigorous proliferation of antigen-specific effector T cells, markedly increased Th1 cytokine secretion and elicited more memory T cells in tumor-bearing mice, consequently enhancing the anti-tumor response and inducing immune protection. Furthermore, we found that TCS upregulated the expression of tumor suppressor in lung cancer 1 (TSLC1) in 3LL tumor cells and the expression of its ligand, class I-restricted T cell-associated molecule (CRTAM), in effector T cells. Blocking TSLC1 expression with small interfering RNA (siRNA) significantly eliminated the effects of TCS on the proliferation and cytokine secretion of effector T cells, suggesting that TCS enhances anti-tumor immune response at least partially by boosting the interaction between TSLC1 and CRTAM. Collectively, our data demonstrate that TCS not only affects tumor cells directly, but also enhances anti-tumor immunity via the interaction between TSLC1 and CRTAM. These findings may lead to the development of a novel approach for tumor regression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • CD4-Positive T-Lymphocytes / drug effects
  • CD4-Positive T-Lymphocytes / metabolism
  • CD8-Positive T-Lymphocytes / drug effects
  • CD8-Positive T-Lymphocytes / metabolism
  • Carcinoma, Lewis Lung / drug therapy*
  • Carcinoma, Lewis Lung / immunology*
  • Carcinoma, Lewis Lung / metabolism
  • Cell Adhesion Molecule-1
  • Cell Adhesion Molecules / genetics
  • Cell Adhesion Molecules / immunology*
  • Cell Adhesion Molecules / metabolism*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cell Survival / drug effects
  • Cytokines / metabolism
  • Female
  • Immunoglobulins / genetics
  • Immunoglobulins / immunology*
  • Immunoglobulins / metabolism*
  • Interferon-gamma / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Nude
  • RNA, Small Interfering / pharmacology
  • Th1 Cells / drug effects
  • Th1 Cells / metabolism
  • Trichosanthin / immunology
  • Trichosanthin / pharmacology*


  • Cadm1 protein, mouse
  • Cell Adhesion Molecule-1
  • Cell Adhesion Molecules
  • Cytokines
  • Immunoglobulins
  • RNA, Small Interfering
  • class-I restricted T cell-associated molecule
  • Trichosanthin
  • Interferon-gamma