Gene expression patterns of breast carcinomas distinguish tumor subclasses with clinical implications.

The purpose of this study was to classify breast carcinomas based on variations in gene expression patterns derived from cDNA microarrays and to correlate tumor characteristics to clinical outcome. A total of 85 cDNA microarray experiments representing 78 cancers, three fibroadenomas, and four normal breast tissues were analyzed by hierarchical clustering. As reported previously, the cancers could be classified into a basal epithelial-like group, an ERBB2-overexpressing group and a normal breast-like group based on variations in gene expression. A novel finding was that the previously characterized luminal epithelial/estrogen receptor-positive group could be divided into at least two subgroups, each with a distinctive expression profile. These subtypes proved to be reasonably robust by clustering using two different gene sets: first, a set of 456 cDNA clones previously selected to reflect intrinsic properties of the tumors and, second, a gene set that highly correlated with patient outcome. Survival analyses on a subcohort of patients with locally advanced breast cancer uniformly treated in a prospective study showed significantly different outcomes for the patients belonging to the various groups, including a poor prognosis for the basal-like subtype and a significant difference in outcome for the two estrogen receptor-positive groups.

The delta1-opioid receptor antagonist, 7-(benzospiroindanyl)naltrexone [correction of 7-benzylspiroindanylnaltrexone], prolongs renal allograft survival in a rat model.

In this study we demonstrate allograft survival in a rat model of renal transplantation using the delta1-opioid receptor antagonist, 7-(benzospiroindanyl)naltrexone [corrected]. Treatment with 7-(benzospiroindanyl)naltrexone [corrected] caused 50% of the rats to survive longer than 100 days (untreated, 11 +/- 3 days). Naltrindole, a delta-opioid receptor antagonist without subtype selectivity, also promoted graft survival but was substantially less effective, suggesting that antagonism at delta1-opioid receptors is involved in allograft survival.

Expression and function of proenkephalin A messenger ribonucleic acid in murine fetal thymocytes.

In recent years we examined the function of the endogenous enkephalins encoded by PEA messenger RNA (mRNA) expressed in murine thymocytes, the precursor cells to T lymphocytes, which are the primary effector cells in cell- mediated immune responses. In the present study, we examined the expression and function of PEA mRNA and enkephalins in fetal thymocytes. By Northern gel and in situ hybridization techniques, we show that PEA mRNA is constitutively expressed in fetal thymocytes early in gestation, with maximal expression occurring on day 15. By birth, PEA mRNA is no longer constitutively expressed, but can be induced by culturing newborn thymocytes with the T cell-specific mitogen, Concanavalin-A. Both a delta-opioid receptor antagonist, naltrindole, and a PEA mRNA-specific antisense complementary DNA enhance the spontaneous proliferation of day 15, but not day 14, fetal thymocytes, consistent with the observation that PEA mRNA is expressed in thymocytes on day 15, but not day 14, of gestation. The enhanced proliferation of day 15 fetal thymocytes is reversed by a delta-opioid receptor agonist, deltorphin. The data suggest that endogenous enkephalins encoded by PEA mRNA expressed in day 15 fetal thymocytes act to inhibit the spontaneous proliferation of these cells, perhaps so that their differentiation into mature T lymphocytes can occur.

Inherited breast carcinoma--prospective findings in 1,194 women at risk.

According to preset criteria, 1,194 women at risk for inherited breast carcinoma were selected and subjected to examination. Six hundred and three women were examined once, 591 were followed for a mean of 1.8 years. Twenty infiltrating cancers (median age 49 years) and 16 precancers (median age 44 years) were found, demonstrating that breast carcinoma continued to occur in the selected families as expected under the hypothesis of dominant inheritance. At first round, 14 (1.2%) infiltrating carcinomas and a total of 22 (1.8%) cancers or precancers were found. Incidence rates of 0.58% pr. year for infiltrating cancers, and 1.04% pr. year for cancer or precancer were calculated. This confirms the tentative conclusions that were drawn in our previous report. These are the first prospective reports documenting how to delineate a high risk group for premenopausal breast cancer, and how to diagnose cancer at an early stage. All but two affected women had cancer without lymph node metastasis. Although a longer observation time is needed, we cautiously conclude that the results are in keeping with our aim of providing safety for those at risk. Clinical use of predictive genetic testing may be implemented within these families.

Met-enkephalin-containing peptides encoded by proenkephalin A mRNA expressed in activated murine thymocytes inhibit thymocyte proliferation.

Murine thymocytes activated with the mitogen Con A express proenkephalin A mRNA (PEA mRNA) and met-enkephalin and/or met-enkephalin-containing peptides ("enkephalins"). This Con A-induced expression of PEA mRNA is modulated by the delta opioid receptor agonist, deltorphin I, in a biphasic, dose-dependent manner. That is, 10(-13) M to 10(-11) M deltorphin enhanced PEA mRNA expression 3- to 3.5-fold over the level induced by Con A alone, and 10(-9) M to 10(-7) M deltorphin inhibited it 40 to 70%. delta opioid receptor antagonists recognizing the delta-2 (naltrindole (NTI) and naltriben (NTB)), but not the delta-1 (7-benzylidenenaltrexone (BNTX)), subtype of opioid receptor described in brain, reversed both the enhancing and inhibiting effects of deltorphin on Con A-induced PEA mRNA expression. In addition, the delta-2 receptor-specific antagonists, NTI and NTB, directly inhibited Con A-induced PEA mRNA expression. The function of the enkephalins expressed by thymocytes was examined by using 1) delta opioid receptor antagonists, 2) PEA mRNA-specific antisense cDNA, and 3) Ab to met-enkephalin, and measuring cell proliferation. All three reagents caused enhancement of Con A-induced proliferation, with effects ranging from two- to fourfold over the response to Con A alone. Again, the delta-2 subtype-specific antagonists, NTI and NTB, were functional and the delta-1 subtype-specific antagonist, BNTX, was not. The PEA mRNA-specific antisense cDNA blocked translation but not transcription of PEA mRNA. The data suggest that 1) endogenous enkephalins induced in thymocytes modulate their own expression through delta-2-like opioid receptors, and 2) these endogenous enkephalins function to inhibit the proliferation of activated thymocytes.