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Targeting HER-3 to elicit antitumor helper T cells against head and neck squamous cell carcinoma.

Kumai T, Ohkuri T, Nagato T, Matsuda Y, Oikawa K, Aoki N, Kimura S, Celis E, Harabuchi Y, Kobayashi H - Sci Rep (2015)

Bottom Line: In this study, we found that HER-3 expression on tumor cells was increased after EGFR inhibition.To establish a novel therapeutic approach for HER-3-positive head and neck carcinoma, we identified a HER-3 helper epitope that could elicit effective helper T cell responses to the naturally processed HER-3-derived epitope presented in a HER-3 expressing tumors.Our results supports the validity of CD4 T cell-dependent HER-3-targeted therapy combined with a broad inhibitor of HER-family.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Asahikawa Medical University, Asahikawa, Japan.

ABSTRACT
HER-3 expression has been reported to act as an important oncoprotein in head and neck squamous cell carcinoma. This protein is known to control tumor proliferation and acquisition of resistance by tumor cells towards EGFR inhibitors, therefore, development of a HER-3-targeted therapy is desirable. In this study, we found that HER-3 expression on tumor cells was increased after EGFR inhibition. To establish a novel therapeutic approach for HER-3-positive head and neck carcinoma, we identified a HER-3 helper epitope that could elicit effective helper T cell responses to the naturally processed HER-3-derived epitope presented in a HER-3 expressing tumors. This epitope induced potent cytolytic activity of CD4 T cells against such tumor cells. Moreover, pan HER-family tyrosine kinase inhibitor augmented the responses of HER-3-reactive CD4 T cells via upregulation of HLA-DR protein on the surface of tumor cells. Our results supports the validity of CD4 T cell-dependent HER-3-targeted therapy combined with a broad inhibitor of HER-family.

No MeSH data available.


Related in: MedlinePlus

Cytotoxicity of HER-3-reactive CD4 T cells toward tumor cells.HER-3-reactive CD4 T cells were tested for their ability to lyse tumor cells at various effector-to-target ratios. HLA-DR-unmatched tumor cell lines (HSC3 or HSC4 cells) served as a negative control. The results shown are representative of 3 experiments that were performed on the same samples. The p-value of each plot was calculated by comparing with the specific tumor lysis in the absent of T cells (Effector-to-target ratio = 0).
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f4: Cytotoxicity of HER-3-reactive CD4 T cells toward tumor cells.HER-3-reactive CD4 T cells were tested for their ability to lyse tumor cells at various effector-to-target ratios. HLA-DR-unmatched tumor cell lines (HSC3 or HSC4 cells) served as a negative control. The results shown are representative of 3 experiments that were performed on the same samples. The p-value of each plot was calculated by comparing with the specific tumor lysis in the absent of T cells (Effector-to-target ratio = 0).

Mentions: Although the HER-3 protein is expressed on tumor cells, presentation of the HER-3872−886 peptide on tumor cells through the endogenous antigen-processing machinery is required for CD4 T cell recognition. To find out whether HER-3872−886 peptide is presented on MHC class II molecules on the surface of tumor cells, we cocultured HER-3-reactive CD4 T cells and HLA-DR-matched HER-3-positive tumor cells, and measured IFN-γ production in the culture supernatants. Because IFN-γ is required to induce MHC class II expression on tumor cells13 and HER-3-reactive CD4 T cells did not react with IFN-γ untreated tumor (data not shown), tumor cells were pretreated with IFN-γ. The results showed that HER-3-reactive CD4 T cells directly reacted with tumor cells in an HLA-DR-restricted manner (Fig. 3). Because cytotoxicity of CD4 T cells is involved in antiviral and antitumor immunity1415, we also evaluated the cytotoxic activity of the HER-3-reactive CD4 T cells against the tumor cells. As shown in Fig. 4, some of these T cell lines were effective in killing HLA-DR-matched HER-3-positive tumor cells. Interestingly, although n24 reacted with the HSC4 tumor cells producing IFN-γ (Fig. 3), these CD4 T cells did not lyse the HSC4 cells. These results indicate that tumor recognition (cytokine production) does not necessarily correlate with lytic function. Because it was possible that readout of this cytotoxicity assay, lactate dehydrogenase (LDH) in the supernatant might be also derived from CD4 T cells due to the coculture with tumor16, HER-3-reactive CD4 T cells were stained with Annexin-V and 7-AAD to clarify the source of LDH in the coculture system. As a result, coculture with tumor had no effect on the viability of the HER-3-reactive CD4 T cells suggesting that LDH was only derived from tumor cells in the cytotoxicity assay (Supplementary Fig. 2). By immunohistochemical staining in human tissues, the level of HER-3 expression was significantly higher in the cancer specimens than in normal mucosa membrane (Supplementary Fig. 3). Because a relatively low concentration of antigen has been reported to induce T cell ignorance17, it is speculated that HER-3 reactive T-cells cannot trigger detrimental autoimmunity. Taken together, these results suggest that the HER-3872−886 epitope could be used to develop antigen-specific CD4 T cell based therapies such as a peptide vaccine for HER-3-positive tumors.


Targeting HER-3 to elicit antitumor helper T cells against head and neck squamous cell carcinoma.

Kumai T, Ohkuri T, Nagato T, Matsuda Y, Oikawa K, Aoki N, Kimura S, Celis E, Harabuchi Y, Kobayashi H - Sci Rep (2015)

Cytotoxicity of HER-3-reactive CD4 T cells toward tumor cells.HER-3-reactive CD4 T cells were tested for their ability to lyse tumor cells at various effector-to-target ratios. HLA-DR-unmatched tumor cell lines (HSC3 or HSC4 cells) served as a negative control. The results shown are representative of 3 experiments that were performed on the same samples. The p-value of each plot was calculated by comparing with the specific tumor lysis in the absent of T cells (Effector-to-target ratio = 0).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4633732&req=5

f4: Cytotoxicity of HER-3-reactive CD4 T cells toward tumor cells.HER-3-reactive CD4 T cells were tested for their ability to lyse tumor cells at various effector-to-target ratios. HLA-DR-unmatched tumor cell lines (HSC3 or HSC4 cells) served as a negative control. The results shown are representative of 3 experiments that were performed on the same samples. The p-value of each plot was calculated by comparing with the specific tumor lysis in the absent of T cells (Effector-to-target ratio = 0).
Mentions: Although the HER-3 protein is expressed on tumor cells, presentation of the HER-3872−886 peptide on tumor cells through the endogenous antigen-processing machinery is required for CD4 T cell recognition. To find out whether HER-3872−886 peptide is presented on MHC class II molecules on the surface of tumor cells, we cocultured HER-3-reactive CD4 T cells and HLA-DR-matched HER-3-positive tumor cells, and measured IFN-γ production in the culture supernatants. Because IFN-γ is required to induce MHC class II expression on tumor cells13 and HER-3-reactive CD4 T cells did not react with IFN-γ untreated tumor (data not shown), tumor cells were pretreated with IFN-γ. The results showed that HER-3-reactive CD4 T cells directly reacted with tumor cells in an HLA-DR-restricted manner (Fig. 3). Because cytotoxicity of CD4 T cells is involved in antiviral and antitumor immunity1415, we also evaluated the cytotoxic activity of the HER-3-reactive CD4 T cells against the tumor cells. As shown in Fig. 4, some of these T cell lines were effective in killing HLA-DR-matched HER-3-positive tumor cells. Interestingly, although n24 reacted with the HSC4 tumor cells producing IFN-γ (Fig. 3), these CD4 T cells did not lyse the HSC4 cells. These results indicate that tumor recognition (cytokine production) does not necessarily correlate with lytic function. Because it was possible that readout of this cytotoxicity assay, lactate dehydrogenase (LDH) in the supernatant might be also derived from CD4 T cells due to the coculture with tumor16, HER-3-reactive CD4 T cells were stained with Annexin-V and 7-AAD to clarify the source of LDH in the coculture system. As a result, coculture with tumor had no effect on the viability of the HER-3-reactive CD4 T cells suggesting that LDH was only derived from tumor cells in the cytotoxicity assay (Supplementary Fig. 2). By immunohistochemical staining in human tissues, the level of HER-3 expression was significantly higher in the cancer specimens than in normal mucosa membrane (Supplementary Fig. 3). Because a relatively low concentration of antigen has been reported to induce T cell ignorance17, it is speculated that HER-3 reactive T-cells cannot trigger detrimental autoimmunity. Taken together, these results suggest that the HER-3872−886 epitope could be used to develop antigen-specific CD4 T cell based therapies such as a peptide vaccine for HER-3-positive tumors.

Bottom Line: In this study, we found that HER-3 expression on tumor cells was increased after EGFR inhibition.To establish a novel therapeutic approach for HER-3-positive head and neck carcinoma, we identified a HER-3 helper epitope that could elicit effective helper T cell responses to the naturally processed HER-3-derived epitope presented in a HER-3 expressing tumors.Our results supports the validity of CD4 T cell-dependent HER-3-targeted therapy combined with a broad inhibitor of HER-family.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Asahikawa Medical University, Asahikawa, Japan.

ABSTRACT
HER-3 expression has been reported to act as an important oncoprotein in head and neck squamous cell carcinoma. This protein is known to control tumor proliferation and acquisition of resistance by tumor cells towards EGFR inhibitors, therefore, development of a HER-3-targeted therapy is desirable. In this study, we found that HER-3 expression on tumor cells was increased after EGFR inhibition. To establish a novel therapeutic approach for HER-3-positive head and neck carcinoma, we identified a HER-3 helper epitope that could elicit effective helper T cell responses to the naturally processed HER-3-derived epitope presented in a HER-3 expressing tumors. This epitope induced potent cytolytic activity of CD4 T cells against such tumor cells. Moreover, pan HER-family tyrosine kinase inhibitor augmented the responses of HER-3-reactive CD4 T cells via upregulation of HLA-DR protein on the surface of tumor cells. Our results supports the validity of CD4 T cell-dependent HER-3-targeted therapy combined with a broad inhibitor of HER-family.

No MeSH data available.


Related in: MedlinePlus