Adrenal lesion in multiple endocrine neoplasia type 1

BACKGROUND

Multiple endocrine neoplasia (MEN) type 1 is accompanied by adrenal involvement, but characteristics and clinical handling of this lesion have been insufficiently explored.

METHODS

Patients with MEN 1 (n = 43) were monitored (mean, 6.3 years) with annual biochemical and radiologic adrenal evaluation. Adrenal specimens were examined by in situ RNA-RNA hybridization for expression of the MEN1 candidate gene phospholipase C beta 3 (PLC beta 3) and immunostaining for insulin-like growth factor-1 receptor.

RESULTS

Altogether 17 patients (40%) displayed adrenal enlargement, which was limited to the adrenal cortex and showed signs of progression, marked atypia, and cancer development in three of them. Only the carcinoma exhibited adrenocortical hormone excess. PLC beta 3 was expressed in the hyperplastic and adenomatous proliferation but not the carcinoma. Pancreatic endocrine tumors with insulin-proinsulin excess were overrepresented in the patients with adrenocortical involvement, but significant insulin-like growth factor-1 receptor immunoreactivity was restricted to the carcinoma.

CONCLUSIONS

The prevalent adrenocortical lesion associated with MEN 1 requires regular attention because of malignant potential. It was unrelated to loss of constitution heterozygosity for the MEN1 locus (11q13) and PLC beta 3 expression, except for the cortical carcinoma exhibiting allelic losses involving also the Wiedemann-Beckwith gene at 11p15. Mechanisms for mitogenic relationships between the pancreatic and adrenal lesions of MEN 1 demand further clarification.

Lack of interleukin-2 (IL-2) expression and selective expression of IL-10 mRNA in human renal cell carcinoma

Freshly isolated tumor-infiltrating lymphocytes (TIL) are often functionally deficient. Since one of the key functional parameters of an immune response is the local production of cytokines, we studied the expression of cytokine genes in freshly isolated renal cancer tissue. Using a PCR-assisted mRNA amplification assay, the constitutive expression of mRNA for 10 different cytokines was assessed in renal cancer tissue. We compared the cytokine mRNA expression in freshly isolated samples of renal carcinomas, renal cancer cell lines established from the tumor samples, peripheral blood mononuclear cells (PBMC) and non-tumor kidney tissue isolated from the same patients. IL-10 mRNA expression was detected only in tumor samples, while renal cancer lines, PBMC and non-tumorous kidney tissues were devoid of this cytokine. One-third of the tumor samples but none of the normal kidney samples also expressed G-CSF mRNA. IL-6, TNF-alpha and IFN-gamma mRNA were expressed non-selectively in tumors, PBMC and normal rental tissue. Expression of IL-2, IL-3 and IL-4 mRNA was not detected in any of the tissues analyzed. Established renal cancer lines exhibited expression of IL-1 alpha, IL-6, TNF-alpha and GM-CSF. Culture of tumor-derived T cells with anti-CD3 monoclonal antibody (MAb) resulted in expression of IL-2, IL-3 and IL-4 mRNA. In contrast, none of these cytokines was detected in culture with recombinant human IL-2 alone. Since IL-10 is known to suppress antigen presentation, these findings have important implications for the possible in vivo role of IL-10 as a suppressor of local anti-tumor response.

Scintigraphy and biodistribution of monoclonal adrenocortical antibody in mice grafted with human adrenocortical carcinoma

BACKGROUND

A murine monoclonal antibody recognizing normal and neoplastic human adrenocortical cells has been evaluated for scintigraphic localization and biodistribution in 53 nude mice grafted subcutaneously with human adrenocortical cell lines SW-13 and T-CAR 1.

METHODS

The immunoglobulin G1 antibody and its Fab'2 fragment were purified and labeled with 125I. The tumor grafts exhibited diameters of 5 to 15 mm at 4 to 6 weeks after transplantation, when mice received a single subcutaneous or intraperitoneal injection of 50 micrograms iodinated intact or fragmented antibody, respectively.

RESULTS

Examination up to 8 days after immunoglobulin G administration showed mean radioactivity ratios less than 1.0 for tumor to blood and corresponding ratios in tumor to lung, liver, spleen, and kidney from 0.6 to 5.3 at the time of peak tumor to blood ratio. A high background activity was noted on scintigraphic tumor visualization with the iodinated immunoglobulin G. In contrast, the radiolabeled Fab'2 fragment displayed gradually rising tumor to blood ratios, which, 4 days after injection, averaged 10.5 for T-CAR1 and 5.3 for SW-13. Tumor transplants were scintigraphically visualized without substantial background activity 3 days after Fab'2 injection, when the ratio of radioactivity in the tumor to the investigated murine organs was 0.5 to 7.3.

CONCLUSIONS

The findings substantiate that immunoscintigraphy with the Fab'2 fragment of the antiadrenocortical Ac5 antibody may become a tool to localize human adrenocortical carcinoma.

P-glycoprotein expression and activity of resistance modifying agents in primary cultures of human renal and adrenocortical carcinoma cells

Tumor cells from patients with renal or adrenocortical carcinomas were tested in vitro for sensitivity to doxorubicin (Dox) and vincristine (Vcr), as well as for the modulation of this sensitivity by resistance modifiers and the immunohistochemical expression of the multidrug resistance associated P-glycoprotein (Pgp). Normal adrenocortical cells from one patient and Pgp-expressing cells of Dox-resistant myeloma RPMI 8226 sublines were included for comparison. The normal adrenocortical cells and cells from one adrenocortical carcinoma showed high Pgp expression, comparable to the most Dox-resistant myeloma cell line, whereas the other tumor samples showed variable but lower expression. The normal adrenocortical as well as the adrenocortical and renal tumor cells were highly resistant to Dox and Vcr. Whereas the cytotoxic effect of Dox was considerably increased by verapamil, cyclosporin A and its non-immunosuppressive analogue SDZ PSC 833 in the Pgp-expressing Dox-resistant sublines, comparatively small effects on the Dox and Vcr sensitivity were observed in the patient samples, irrespective of their Pgp expression. The results indicate that the Dox and Vcr resistance in human adrenocortical and renal carcinomas is mediated by mechanisms other than Pgp and that resistance modulating agents targeting Pgp may be much less efficient in the clinic than in Pgp-expressing cell lines, at least for the tumor types described in the present study.

Monoclonal antibodies against the putative divalent cation-receptor that is located on parathyroid cells do not stain isolated rat osteoclasts

It has been reported that osteoclastic function is regulated by calcium-induced alterations in cytoplasmic free calcium ([Ca2+]i), possibly through a specific receptor. We have investigated whether osteoclasts, isolated from neonatal rat long bones, possess the divalent cation-receptor that has been demonstrated on parathyroid cells. Studies with fura-2 loaded adherent single cells showed that an increase in extracellular Ca2+ ([Ca2+]e) from 0.5 mM to 10 mM resulted in an increase in [Ca2+]i in isolated rat osteoclasts, from a basal value of 94.7 +/- 16.2 to 150.6 +/- 22.4 nM (means +/- SEM; n = 14). The shape and time course of the [Ca2+]i increase varied considerably from cell to cell. Less than half of the cells responded with a rapid transient increase whereas the rest responded with a slow increase that reached a plateau within 1-2 minutes. When [Ca2+]e was changed back to 0.5 mM, a slow decrease in [Ca2+]i was monitored. Immunohistochemical staining with two different monoclonal antibodies, recognizing the putative Ca2+ receptor on parathyroid cells, did not indicate any staining on freshly isolated rat osteoclasts. Thus, our data demonstrate that an increase in [Ca2+]e causes an elevation of [Ca2+]i in osteoclasts. This increase is not mediated via the putative cation-receptor found on parathyroid cells.

Cytotoxic activity and T cell receptor repertoire in tumor-infiltrating lymphocytes of adrenal cell carcinomas

The cytotoxic activity and T cell receptor (TCR) V beta repertoire in tumor-infiltrating lymphocytes (TIL) of three primary adrenal cell carcinomas were analyzed. Fresh, non-cultured TIL from two of the three tumors showed low but significant lysis of the autologous tumor, and for one of the patients this activity was strongly enhanced upon culture in interleukin-2. An allogeneic adrenal cell carcinoma line and the K562 or Daudi targets included as controls were not killed. Phenotypic analysis of freshly isolated TIL demonstrated that the cells from the two patients that demonstrated cytolytic capacity mainly consisted of CD45RO+ T cells. In vitro cultured TIL lines from these patients demonstrated a high percentage of CD8+ cells expressing either the V beta 6 gene or the V beta 8 gene product, as measured with a panel of mAb specific for TCR V alpha and V beta gene products. Analysis of the TCR V beta gene mRNA expression in freshly isolated non-cultured TIL, using a polymerase-chain-reaction-assisted cDNA-amplification assay, confirmed the strong expression of the genes coding for the TCR V beta 6 or the V beta 8. This assay also demonstrated a more restricted TCR V beta gene usage in the TIL as compared to peripheral blood lymphocytes from the same patient.

Monoclonal antibodies raised against mid-gut carcinoid tumor cells

Three monoclonal IgG 2a antibodies were produced after immunization of mice with dispersed cells from a human mid-gut carcinoid tumor. Acetone-fixed cryosections of 57 primary and metastatic mid-gut carcinoid tumors as well as 2 hind-gut (rectal) carcinoids showed a conspicuous immunoreaction while a thymic carcinoid was essentially unstained with the antibodies. The 3 antibodies yielded a similar pattern of immunostaining. The immunoreaction comprised more than 95% of the carcinoid tumor cells, and it was more uniform and intense in primary tumors than in mesenteric, hepatic, and ovarian metastases of the mid-gut carcinoid tumors. Immunofluorescence studies on suspended carcinoid tumor cells showed that the antibodies bound to the surface membrane of the cells. The antibodies immunostained enterocytes of the small and large bowel, intestinal metaplasia of the stomach mucosa as well as colorectal adenocarcinomas. Endocrine pancreatic tumors producing vasoactive intestinal polypeptide, gastrin, somatostatin, and/or pancreatic polypeptide as well as the epithelium of pancreatic ducts were also stained with the antibodies, whereas a large number of other normal and abnormal human tissues, including benign and malignant insulinomas, were unreactive. The findings indicate that the antibodies recognize differentiation antigens on the carcinoid tumor cell surface preserved also on endocrine and nonendocrine cells of the normal bowel mucosa. The restricted tissue reactivity of the antibodies suggests that they may constitute useful tools in the histological characterization of carcinoid tumors. Further studies may reveal if they are applicable for immunolocalization and perhaps even immunotherapy of these neoplasms.