Female gender is a significant independent favorable prognostic factor in lung cancer. To study the possible role of sex hormones in lung cancer, the expression of sex-steroid receptors and the glucocorticoid receptor was investigated in 29 lung-cancer cell lines stemming from small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC) by means of immunocytochemistry, ligand-binding assays and RNA expression via polymerase chain reaction. In at least 2 methods of investigation, NSCLC cell lines showed a low expression of estrogen receptor in 6, progesterone receptor in 13 and androgen receptor in I2 out of 17 cases examined; sex-steroidreceptor expression was virtually absent in SCLC cell lines. The glucocorticoid receptor was expressed in all 29 cell lines studied. Additionally, 52 tumor samples from primary lung cancer were investigated for their receptor expression by means of immunohistochernistry. Among patients with primary lung-cancer sex-steroid-receptor expression in tumor biopsies was detected most frequently in female patients (in 69% of I6 cases, vs. 42% of 36 tumors from men) and in patients with adenocarcinoma. Further research will focus on these subgroups. lmmunohistology is a feasible method of studying steroid-receptor expression in lung cancer.o 1996 Wiley-Lhs, Inc.Analyses of large clinical trials have shown that female gender is a significant independent favorable prognostic factor in small-cell lung cancer (Albain et al., 1990;Johnson et al., 1988). Further multivariate analysis of a German multicenter study comprising 766 patients revealed significance only for women under the age of 60 years (Wolf et al., 1991). Two studies of patients with unresectable non-small-cell lung cancer who were treated with chemotherapy also showed a longer survival rate for women (O'Connell et al., 1986;Finkelstein et al., 1986).To determine the influence and possible therapeutical value of sex hormones in lung cancer, we decided to study the expression of their receptors in lung-cancer cell lines and tumor biopsies, since these are a prerequisite for steroid action. There are basically 3 methods for the detection of steroid-hormone receptors: gene expression, binding assays and immunohistochemistry. The gene expression of receptors has not been investigated in lung cancer so far. Binding assays which use radioactive ligands in whole-cell or cytosolic assays are the standard method for studying receptor expression. Immunohistochemistry uses monoclonal antibodies and has been well established for the detection of estrogen receptors and progesterone receptors in breast cancer. Numerous studies have shown a close correlation between immunocytochemical methods and binding assays in mammary carcinoma (Charpin et UL, 1986).The diagnosis of lung cancer is made predominantly on small bronchoscopic biopsies or cytological specimens. Therefore binding assays for which large amounts of fresh tissue have to be provided cannot readily be performed. Immunohistochemistry may overcome this problem, since this method ...

Considerable evidence exists that lung cancer cell lines produce large amounts of insulin-like growth factor-binding proteins (IGFBPs). In addition, these cells are subject to an autocrine or paracrine growth control by insulin-like growth factors (IGFs). We now demonstrate by immunocytochemistry with IGFBP-3 antibodies that nuclei of a lung cancer cell line distinctly immunostain for IGFBP-3. This finding led us to investigate in more detail the localization of this protein that, to date, had only been known to occur extracellularly. Ligand blotting revealed that purified nuclear extracts contain a 43,000-Da IGFBP which can bind [I125]IGF-I. By Western blot this protein was identified as IGFBP-3. Thus, our data are consistent with the results of a previous structural study predicting a nuclear localization for IGFBP-3. Moreover, our findings raise the possibility that nuclear IGFBP-3 is functional and involved in the pathogenesis of lung cancer.

IGF-I and IGF-II are potent mitogens, postulated to exert autocrine/paracrine effects on growth regulation in human lung cancer. Their proliferative effects are modulated by IGF-binding proteins (IGFBPs), which are found in conditioned medium (CM) of lung cancer cell lines. The biological role of the IGFBPs, which are ontogenetically and hormonally regulated, is not fully understood. Both inhibitory and stimulatory effects on cell growth have been demonstrated. Exogenous IGFBP-3 has been consistently shown to block IGF action, inhibiting cell growth in vitro. In order to evaluate the action of endogenously produced IGFBP-3 on cell growth in lung cancer, we stably transfected the non-small cell lung cancer cell line NCI-H23 with human IGFBP-3 cDNA (resulting in NCI-H23 pOPI3/BP-3) or with the vector pOPI3CAT as control (resulting in NCI-H23 pOPI3CAT). RT-PCR confirmed expression of IGFBP-3-specific mRNA in NCI-H23 pOPI3/BP-3, but not in NCI-H23 or NCI-H23 pOPI3CAT. Western ligand blot and Western immunoblot analysis of CMs yielded strong signals of the characteristic 40-44 kDa human IGFBP-3 protein in NCI-H23 pOPI3/BP-3. An IGFBP-3 ELISA demonstrated a 20-fold increase in IGFBP-3 protein expression in NCI-H23 pOPI3/BP-3 as compared with NCI-H23. The growth of NCI-H23 pOPI3/BP-3 in serum-containing medium was significantly slower (1·7-fold) than that of NCI-H23 or the vector-transfected control NCI-H23 pOPI3CAT. While the proliferation rate of parental and vectortransfected cells could be stimulated by IGF-I, IGF-II, IGF-I analog Long R 3 IGF-I or insulin, that of NCI-H23 pOPI3/BP-3 could not. Xenotransplantation in nude mice resulted in marked tumor growth after the injection of NCI-H23 or NCI-H23 pOPI3CAT, but absent or minimal growth for the IGFBP-3-transfected cell line.These data suggest that IGFBP-3 is a potent inhibitor of cell growth in human lung cancer cell lines and may impair tumorigenicity in vivo.

The active metabolite of vitamin D 1,25-dihydroxycholecalciferol is a hormone-like agent that regulates cell differentiation and proliferation. Various vitamin D derivatives have been shown to induce differentiation in neoplastic cells. The prerequisite for any hormone action is the presence of its receptor. We studied the expression of vitamin D receptor in human lung cancer cell lines and in primary lung cancer tissue. Employing the polymerase chain reaction, 10 out of 11 cell lines stemming from small-cell lung cancer and 15 out of 15 cell lines stemming from non-small-cell lung cancer demonstrated vitamin D receptor expression. An immunohistochemical analysis, using a specific monoclonal antibody, demonstrated vitamin D receptor protein expression in 31 out of 117 (26%) primary small-cell lung cancer cases tested. Positive cells exhibited a nuclear reaction pattern. Twenty-one out of 37 primary non-small-cell lung cancer cases, particularly adenocarcinomas (9/14) and squamous-cell carcinomas (10/15), exhibited vitamin D receptor. Results indicate that a subset of lung cancer cases may be susceptible to the differentiating effects of vitamin D analogues.

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