Antibody Selection for Cancer Target Validation of FSH-Receptor in Immunohistochemical Settings

Abstract

Background: The follicle-stimulating hormone (FSH)-receptor (FSHR) has been reported to be an attractive target for antibody therapy in human cancer. However, divergent immunohistochemical (IHC) findings have been reported for FSHR expression in tumor tissues, which could be due to the specificity of the antibodies used. Methods: Three frequently used antibodies (sc-7798, sc-13935, and FSHR323) were validated for their suitability in an immunohistochemical study for FSHR expression in different tissues. As quality control, two potential therapeutic anti-hFSHR Ylanthia ® antibodies (Y010913, Y010916) were used. The specificity criteria for selection of antibodies were binding to native hFSHR of different sources, and no binding to non-related proteins. The ability of antibodies to stain the paraffin-embedded Flp-In Chinese hamster ovary (CHO)/FSHR cells was tested after application of different epitope retrieval methods. Results: From the five tested anti-hFSHR antibodies, only Y010913, Y010916, and FSHR323 showed specific binding to native, cell-presented hFSHR. Since Ylanthia ® antibodies were selected to specifically recognize native FSHR, as required for a potential therapeutic antibody candidate, FSHR323 was the only antibody to detect the receptor in IHC/histochemical settings on transfected cells, and at markedly lower, physiological concentrations (ex., in Sertoli cells of human testes). The pattern of FSH323 staining noticed for ovarian, prostatic, and renal adenocarcinomas indicated that FSHR was expressed mainly in the peripheral tumor blood vessels. Conclusion: Of all published IHC antibodies tested, only antibody FSHR323 proved suitable for target validation of hFSHR in an IHC setting for cancer. Our studies could not confirm the previously reported FSHR overexpression in ovarian and prostate cancer cells. Instead, specific overexpression in peripheral tumor blood vessels could be confirmed after thorough validation of the antibodies used.

Extragonadal FSHR Expression and Function—Is It Real?

“…Basic information on selected popular FSHR antibodies is listed in Table 1A. The specificity of two frequently used antibodies, sc-7798 and sc-13935, from Santa Cruz Biotechnology, has been recently revisited (47). In a comprehensive study, the authors compared these antibodies with FSHR323 (44) and two potential therapeutic anti-hFSHRs Ylanthia® antibodies (Y010913, Y010916) for their suitability in IHC detection of FSHR expression in various tissues (47).…”

Direct actions of gonadotropins beyond the reproductive system and their role in human aging and neoplasia [Bezpośrednie działanie gonadotropin poza układem rozrodczym i ich rola w starzeniu się i nowotworzeniu u człowieka]

“…Moreover, FSH, LH, and hCG were shown to enhance several cytokines from the human peripheral blood mononuclear cells in vitro. The above concerns interferon-gamma [47], interleukin-6 [48], interleukin Pawlikowski et al [19] revealed immunopositivity with anti-FSHR antibody in human non-neoplastic adrenal cortex as well as in benign and malignant adrenal tumours; however, the specificity of this immunoreaction is still under discussion [20] Nervous system One of the earliest findings of the direct action of gonadotropins on the nervous system was the observation of degenerative changes in autonomic gangliocytes after FSH or LH administration in hypophysectomised-gonadectomised rats [1]. Further evidence of the direct gonadotropin action of either LH or FSH on neurons was the discovery of "short" feedback loops in the control of gonadotropin secretion.…”

“…Innym dowodem bezpośredniego działania LH lub FSH na neurony było odkrycie "krótkiej" pętli sprzężenia zwrotnego w kontroli wydzielania gonadotropin. Wykazano mianowicie, że implantacja LH [19] lub FSH [20] do wyniosłości pośrodkowej prowadzi do spadku wydzielania odpowiednich hormonów przypuszczalnie przez zahamowanie neuronów podwzgórzowych produkujących GnRH. Wykazano także, że LH moduluje także aktywność hipokampa u szczura [21].…”

Correction: Moeker, N.; et al. Antibody Selection for Cancer Target Validation of FSH-Receptor in Immunohistochemical Settings. Antibodies 2017, 6, 15

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The authors wish to make the following correction to the Conflict of Interests section in their published paper [1]:"Christian Kunz and Solveig Peters are employees and Nina Möker and Robert Rauchenberger are former employees of MorphoSys AG, which owns the Ylanthia antibodies described in the publication. "

The manuscript will be updated and the original will remain online on the article webpage.

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“…The authors wish to make the following correction to the Conflict of Interests section in their published paper [1]:…”