Immunotherapy and immunoescape in colorectal cancer.
Immunotherapy encompasses a variety of interventions and techniques with the common goal of eliciting tumor cell destructive immune responses. Colorectal carcinoma often presents as metastatic disease that impedes curative surgery. Novel strategies such as active immunization with dendritic cells (DCs), gene transfer of cytokines into tumor cells or administration of immunostimulatory monoclonal antibodies (such as anti-CD137 or anti-CTLA-4) have been assessed in preclinical studies and are at an early clinical development stage. Importantly, there is accumulating evidence that chemotherapy and immunotherapy can be combined in the treatment of some cases with colorectal cancer, with synergistic potentiation as a result of antigens cross-presented by dendritic cells and/or elimination of competitor or suppressive T lymphocyte populations (regulatory T-cells). However, genetic and epigenetic unstable carcinoma cells frequently evolve mechanisms of immunoevasion that are the result of either loss of antigen presentation, or an active expression of immunosuppressive substances. Some of these actively immunosuppressive mechanisms are inducible by cytokines that signify the arrival of an effector immune response. For example, induction of 2, 3 indoleamine dioxygenase (IDO) by IFNgamma in colorectal carcinoma cells. Combinational and balanced strategies fostering antigen presentation, T-cell costimulation and interference with immune regulatory mechanisms will probably take the stage in translational research in the treatment of colorectal carcinoma.
Mazzolini
Guillermo
G
Liver Unit, Facutad de Ciencias Biomédicas, Universidad Austral, Av Presidente Péron 1500, (1635) Derqui-Pilar, Buenos Aires, Argentina. gmazzoli@cas.austral.edu.ar
Murillo
Oihana
O
Atorrasagasti
Catalina
C
Dubrot
Juan
J
Tirapu
Iñigo
I
Rizzo
Miguel
M
Arina
Ainhoa
A
Alfaro
Carlos
C
Azpilicueta
Arantza
A
Berasain
Carmen
C
Perez-Gracia
José L
JL
Gonzalez
Alvaro
A
Melero
Ignacio
I
D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D015179:Colorectal Neoplasms / Q000235:genetics / Q000276:immunology* / Q000628:therapy*; D015316:Genetic Therapy; D006801:Humans; D007114:Immunization; D007167:Immunotherapy / Q000379:methods*; D019139:Tumor Escape / Q000276:immunology
D000911:Antibodies, Monoclonal