Limits...
Accumulation of an endogenous tryptophan-derived metabolite in colorectal and breast cancers.

Puccetti P, Fallarino F, Italiano A, Soubeyran I, MacGrogan G, Debled M, Velasco V, Bodet D, Eimer S, Veldhoen M, Prendergast GC, Platten M, Bessede A, Guillemin GJ - PLoS ONE (2015)

Bottom Line: We developed a monoclonal antibody targeting l-kynurenine as an in situ biomarker of IDO-1/-2 or TDO2 activity.Using Tissue Micro Array technology and immunostaining, colorectal and breast cancer patients were phenotyped based on l-kynurenine production.In colorectal cancer l-kynurenine was not unequivocally associated with IDO-1 expression, suggesting that the mere expression of tryptophan catabolic enzymes is not sufficiently informative for optimal immunotherapy.

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.

ABSTRACT
Tumor immune escape mechanisms are being regarded as suitable targets for tumor therapy. Among these, tryptophan catabolism plays a central role in creating an immunosuppressive environment, leading to tolerance to potentially immunogenic tumor antigens. Tryptophan catabolism is initiated by either indoleamine 2,3-dioxygenase (IDO-1/-2) or tryptophan 2,3-dioxygenase 2 (TDO2), resulting in biostatic tryptophan starvation and l-kynurenine production, which participates in shaping the dynamic relationship of the host's immune system with tumor cells. Current immunotherapy strategies include blockade of IDO-1/-2 or TDO2, to restore efficient antitumor responses. Patients who might benefit from this approach are currently identified based on expression analyses of IDO-1/-2 or TDO2 in tumor tissue and/or enzymatic activity assessed by kynurenine/tryptophan ratios in the serum. We developed a monoclonal antibody targeting l-kynurenine as an in situ biomarker of IDO-1/-2 or TDO2 activity. Using Tissue Micro Array technology and immunostaining, colorectal and breast cancer patients were phenotyped based on l-kynurenine production. In colorectal cancer l-kynurenine was not unequivocally associated with IDO-1 expression, suggesting that the mere expression of tryptophan catabolic enzymes is not sufficiently informative for optimal immunotherapy.

Show MeSH

Related in: MedlinePlus

Immunodetection of l-kynurenine in colorectal and breast tumour specimens.A and B, Representative micrographs of immunohistochemical stainings of paraffin-embedded healthy epithelia and colorectal or breast cancer samples using specific antibodies targeting kynurenine (clone 3D4-F2). On the right panel, graph represents kynurenine immunoscore (obtained from 2 independent TMA cores) with % of Kynurenine positive patients. (C) Representative micrographs of kynurenine immunostainings of paraffin-embedded breast cancer microenvironment.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4400104&req=5

pone.0122046.g002: Immunodetection of l-kynurenine in colorectal and breast tumour specimens.A and B, Representative micrographs of immunohistochemical stainings of paraffin-embedded healthy epithelia and colorectal or breast cancer samples using specific antibodies targeting kynurenine (clone 3D4-F2). On the right panel, graph represents kynurenine immunoscore (obtained from 2 independent TMA cores) with % of Kynurenine positive patients. (C) Representative micrographs of kynurenine immunostainings of paraffin-embedded breast cancer microenvironment.

Mentions: Tryptophan catabolism is known to be involved in tumor progression by favoring immune escape and tumor-induced immune suppression [7, 15, 16]. Inhibition of tryptophan catabolic enzymes represents an attractive therapeutic strategy, aiming at reinstalling an effective tumor-specific protective immunity [19–21]. We investigated the local production of l-kynurenine, the first metabolite produced through the kynurenine pathway (Fig 1), in two different types of human tumors, namely, colorectal and breast cancers (See patients characteristics in S1 and S2 Tables). In attempt to detect l-kynurenine in situ we developed a monoclonal antibody. The antibody was demonstrated to be highly affine and specific for its target (S1 Fig). Colorectal (CRC) and breast cancer specimens were then assayed by IHC on tissue microarrays (TMA). As a control, normal tissue was included for each histotype. Because there occur caveats on removing tissue cores from a whole tumor section—particularly when dealing with non-homogenous staining profiles (as it is the case for kynurenine; S2 Fig)—we evaluated profiles on two independent cores from each tumor specimen. Of the 69 CRC samples tested, 14 (20.3%) stained positive for l-kynurenine (Fig 2A). Because healthy colon epithelial cells were negative, and weak positivity was observed in gut-infiltrating immunocytes, tumor samples were considered competent for kynurenine production when the IHC score was ≥ 1. To confirm the specificity of 3D4-F2 staining, the antibody was incubated with the kynurenine conjugate before staining a colorectal sample found to be positive for l-kynurenine. Pre-exposure of the antibody to the conjugate completely abolished its ability to stain the otherwise positive tumor sample (S3 Fig), demonstrating the specificity of the staining.


Accumulation of an endogenous tryptophan-derived metabolite in colorectal and breast cancers.

Puccetti P, Fallarino F, Italiano A, Soubeyran I, MacGrogan G, Debled M, Velasco V, Bodet D, Eimer S, Veldhoen M, Prendergast GC, Platten M, Bessede A, Guillemin GJ - PLoS ONE (2015)

Immunodetection of l-kynurenine in colorectal and breast tumour specimens.A and B, Representative micrographs of immunohistochemical stainings of paraffin-embedded healthy epithelia and colorectal or breast cancer samples using specific antibodies targeting kynurenine (clone 3D4-F2). On the right panel, graph represents kynurenine immunoscore (obtained from 2 independent TMA cores) with % of Kynurenine positive patients. (C) Representative micrographs of kynurenine immunostainings of paraffin-embedded breast cancer microenvironment.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4400104&req=5

pone.0122046.g002: Immunodetection of l-kynurenine in colorectal and breast tumour specimens.A and B, Representative micrographs of immunohistochemical stainings of paraffin-embedded healthy epithelia and colorectal or breast cancer samples using specific antibodies targeting kynurenine (clone 3D4-F2). On the right panel, graph represents kynurenine immunoscore (obtained from 2 independent TMA cores) with % of Kynurenine positive patients. (C) Representative micrographs of kynurenine immunostainings of paraffin-embedded breast cancer microenvironment.
Mentions: Tryptophan catabolism is known to be involved in tumor progression by favoring immune escape and tumor-induced immune suppression [7, 15, 16]. Inhibition of tryptophan catabolic enzymes represents an attractive therapeutic strategy, aiming at reinstalling an effective tumor-specific protective immunity [19–21]. We investigated the local production of l-kynurenine, the first metabolite produced through the kynurenine pathway (Fig 1), in two different types of human tumors, namely, colorectal and breast cancers (See patients characteristics in S1 and S2 Tables). In attempt to detect l-kynurenine in situ we developed a monoclonal antibody. The antibody was demonstrated to be highly affine and specific for its target (S1 Fig). Colorectal (CRC) and breast cancer specimens were then assayed by IHC on tissue microarrays (TMA). As a control, normal tissue was included for each histotype. Because there occur caveats on removing tissue cores from a whole tumor section—particularly when dealing with non-homogenous staining profiles (as it is the case for kynurenine; S2 Fig)—we evaluated profiles on two independent cores from each tumor specimen. Of the 69 CRC samples tested, 14 (20.3%) stained positive for l-kynurenine (Fig 2A). Because healthy colon epithelial cells were negative, and weak positivity was observed in gut-infiltrating immunocytes, tumor samples were considered competent for kynurenine production when the IHC score was ≥ 1. To confirm the specificity of 3D4-F2 staining, the antibody was incubated with the kynurenine conjugate before staining a colorectal sample found to be positive for l-kynurenine. Pre-exposure of the antibody to the conjugate completely abolished its ability to stain the otherwise positive tumor sample (S3 Fig), demonstrating the specificity of the staining.

Bottom Line: We developed a monoclonal antibody targeting l-kynurenine as an in situ biomarker of IDO-1/-2 or TDO2 activity.Using Tissue Micro Array technology and immunostaining, colorectal and breast cancer patients were phenotyped based on l-kynurenine production.In colorectal cancer l-kynurenine was not unequivocally associated with IDO-1 expression, suggesting that the mere expression of tryptophan catabolic enzymes is not sufficiently informative for optimal immunotherapy.

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.

ABSTRACT
Tumor immune escape mechanisms are being regarded as suitable targets for tumor therapy. Among these, tryptophan catabolism plays a central role in creating an immunosuppressive environment, leading to tolerance to potentially immunogenic tumor antigens. Tryptophan catabolism is initiated by either indoleamine 2,3-dioxygenase (IDO-1/-2) or tryptophan 2,3-dioxygenase 2 (TDO2), resulting in biostatic tryptophan starvation and l-kynurenine production, which participates in shaping the dynamic relationship of the host's immune system with tumor cells. Current immunotherapy strategies include blockade of IDO-1/-2 or TDO2, to restore efficient antitumor responses. Patients who might benefit from this approach are currently identified based on expression analyses of IDO-1/-2 or TDO2 in tumor tissue and/or enzymatic activity assessed by kynurenine/tryptophan ratios in the serum. We developed a monoclonal antibody targeting l-kynurenine as an in situ biomarker of IDO-1/-2 or TDO2 activity. Using Tissue Micro Array technology and immunostaining, colorectal and breast cancer patients were phenotyped based on l-kynurenine production. In colorectal cancer l-kynurenine was not unequivocally associated with IDO-1 expression, suggesting that the mere expression of tryptophan catabolic enzymes is not sufficiently informative for optimal immunotherapy.

Show MeSH
Related in: MedlinePlus