Down-regulation of the desmosomal cadherin desmocollin 3 in human breast cancer.

In previous studies using cDNA microarray analysis, we have identified an expressed sequence tag which is consistently down-regulated in six human breast tumor cell lines. In the current study, we have determined this tag to be part of the mRNA sequence of human desmocollin 3, a member of the cadherin superfamily of proteins and an integral component of desmosomes. Desmosomes are sites of adhesion between adjacent cells in layers of epithelia, as well as in some non-epithelial tissues, and play an important role in the maintenance of tissue structure. Northern analysis, quantitative real-time polymerase chain reaction assay and Western blot analysis showed that desmocollin 3 is present in normal and immortalized human mammary epithelial cells, but consistently exhibits a significant, and often complete, down-regulation in breast cancer cell lines and primary breast tumors, both at the mRNA and protein levels.

Mutual information analysis as a tool to assess the role of aneuploidy in the generation of cancer-associated differential gene expression patterns.

Most human tumors are characterized by: (1) an aberrant set of chromosomes, a state termed aneuploidy; (2) an aberrant gene expression pattern; and (3) an aberrant phenotype of uncontrolled growth. One of the goals of cancer research is to establish causative relationships between these three important characteristics. In this paper we were searching for evidence that aneuploidy is a major cause of differential gene expression. We describe how mutual information analysis of cancer-associated gene expression patterns could be exploited to answer this question. In addition to providing general guidelines, we have applied the proposed analysis to a recently published breast cancer-associated gene expression matrix. The results derived from this particular data set provided preliminary evidence that mutual information analysis may become a useful tool to investigate the link between differential gene expression and aneuploidy.

Synthesis and in vitro activity of some epimeric 20 alpha-hydroxy, 20-oxime and aziridine pregnene derivatives as inhibitors of human 17 alpha-hydroxylase/C17,20-lyase and 5 alpha-reductase.

Some epimeric 20-hydroxy, 20-oxime, 16 alpha, 17 alpha-, 17,20- and 20,21-aziridine derivatives of progesterone were synthesized and evaluated as inhibitors of human 17 alpha-hydroxylase/C17,20-lyase (P450(17) alpha) and 5 alpha-reductase (5 alpha-R). The reduction of 16-dehydropregenolone acetate (3a) was reinvestigated. NaBH4 in the presence of CeCl3 gave better stereo-selectivity for 20 beta-ol [20 alpha/20 beta-OH (4 alpha/4 beta) = 1/2.7] than LTBAH or the Meerwein-Pondroff method reported; reduction with Zn in HOAc formed exclusively 20 alpha-ol (4 alpha b). The 20 alpha- and 20 beta-hydroxy-4,16-pregnadien-3-one (9 alpha) and (9 beta) were synthesized from the alcohols 4 alpha b and 4 beta b. Several 20-oxime pregnadienes and 16 alpha, 17 alpha-, 17,20- and 20,21-aziridinyl-5-pregnene derivatives were also synthesized. LiAlH4 reduction of the 16-en-20-oxime (12b) yielded 20 (R)-(13a) and 20(S)-17 alpha,20-aziridine (13b) and 20(R)-17 beta,20-aziridine (14a). Several compounds inhibited the human P450(17) alpha with greater potency than ketoconzole. The 5 alpha-R enzyme assay showed that while (9 alpha) did not have any activity, (9 beta) and (3b) were potent 5 alpha-reductase (IC50 = 21 and 31 nM) inhibitors with activities similar to finasteride. The 20-oximes (17a) and (17b) were potent dual inhibitors for both 5 alpha-R (IC50 = 63 and 115 nM, compared to 33 nM for finasteride) and P450(17) alpha (IC50 = 43 and 25 nM, compared to 78 nM for ketoconazole).

17-Imidazolyl, pyrazolyl, and isoxazolyl androstene derivatives. Novel steroidal inhibitors of human cytochrome C17,20-lyase (P450(17 alpha).

We recently described a number of inhibitors of P450(17 alpha), the key enzyme of androgen biosynthesis. Here, we report the synthesis and activity of novel 17-imidazolyl, pyrazolyl, and isoxazolyl androstene derivatives as potential agents for the treatment of prostatic cancer. A number of 17-(4'-Imidazolyl) derivatives were prepared by condensing the corresponding 17-ketol acetate side chain with aldehyde and ammonium hydroxide. The 17 beta-(4'imidazolyl) derivatives (2a, 2e, 4a, 4c) were found to be potent inhibitors of human testicular P450(17 alpha), with greater activity than ketoconazole. The juxtaposition between the imidazole ring and the steroid D ring appears to be important in contributing inhibitory properties, Compounds having a 17 beta-(2'-imidazolyl) ring (9a, 10) or a 20 beta-(2'-imidazolyl) ring (12), instead of the 17 beta-(4'-imidazolyl) ring (2a, 4a), are weak inhibitors. Among the 17-(4'-imidazolyl) derivatives, introduction of the 17 alpha-hydroxy group (4b) and 16 alpha,17 alpha-epoxide group (2d) diminished potency (2a-->2d; lC50 66-->430 nM; 4a-->4b; lC50 58-->1200 nM), while the 16,17 double bond increased the inhibitory activity by almost three times in the 5-en-3 beta-ol inhibitors (2a-->2e; lC50 60-->24 nM). There was virtually no difference in the inhibitory activity in the 4-en-3-one inhibitors (4a-->4c; IC50 58-->50 nM). The introduction of a methyl (2b) or phenyl group (2c) on the 2'-position of 4'-imidazolyl ring caused a dramatic decrease in the potency. As to modification of the A,B rings, the 3-acetate (2f, 2g) decreased the potency almost 3-fold compared with the 3-alcohol (2e-->2f, IC50 24-->75 nM; 2a-->2g, 66-->199 nM) and the conversion from the 5-en-3 beta-ol into the 4-en-3-one hardly affected the potency. As expected, 4c was more potent than 2e for the rat p450(17 alpha). 17-(3'Pyrazolyl)-(14b) and 17-(5'-isoxazolyl)-androsta-5,16-dien-3 beta-ol (15b) were also potent inhibitors of P450(17 alpha), whereas the 17-(2'-imidazolyl) compound (9b) was one of the most potent inhibitor in this series. However, their 16-saturated counterparts (9a, 14a, 15a) were weak inhibitors. The 17 beta-(3'-isoxazolyl)- (16) and 17 beta-(5'-methyl-3'-oxazolyl)androst-5-en-3 beta-ol (18) were also inactive. The introduction of a methyl of phenyl group on the nitrogen of the pyrazolyl ring of 14b [see 14c, 14d, and 14e] also caused some loss of inhibition for P450(17 alpha). Compounds 2e, 4a, 4c, 9b, 14d, 17a, and 17b are among the most potent inhibitors of human P450(17 alpha) so far reported.

Synthesis of novel 21-trifluoropregnane steroids: inhibitors of 17 alpha-hydroxylase/17,20-lyase (17 alpha-lyase).

Novel 21-trifluoropregnenolone (6), 21-trifluoroprogesterone (7) and related compounds 4a and 8 have been synthesized in high yields from 3 beta-acetoxyandrost-5-ene-17 beta-carbaldehyde (3). The key reaction was the conversion of 3 into the 21-trifluoromethyl-20-alcohol as a diastereomeric mixture (4) by trifluoromethyltrimethylsilane (TMS-CF3) in the presence of tetrabutylammonium fluoride (TBAF). All compounds, including 6 and 7, were unambiguously characterized by IR, 1H and 19F NMR, high-resolution mass spectrometry (HRMS), and elemental analysis. On this basis, we concluded that the only report of an earlier synthesis of 6 and 7 is erroneous. Enzyme inhibition studies showed that 20 xi-hydroxy-21-trifluoropregn-4-en-3-one (8) is a potent inhibitor (IC50 value = 0.6 microM) of rat 17 alpha-hydroxylase/17,20-lyase.

Growth inhibition of human prostate cells in vitro by novel inhibitors of androgen synthesis.

The long-standing strategy for the treatment of metastatic prostate cancer has been to reduce androgenic stimulation of tumor growth by removal of the testes, the primary site of testosterone synthesis. However, a low level of androgenic stimulation may continue, even after castration, by the conversion of adrenal androgens to 5alpha-dihydrotestosterone (DHT) in the prostate tumor cells. Two important enzymes of the androgen biosynthetic pathway are 17alpha-hydroxylase/C17,20-lyase, which regulates an early step in the synthesis of testosterone and other androgens in both the testes and adrenal glands, and 5alpha-reductase, which converts testosterone to the more potent androgen, DHT, in the prostate. We have identified new inhibitors of these enzymes that may be of use in achieving a more complete ablation of androgens in the treatment of metastatic prostate cancer. Three derivatives of androstene were shown to inhibit 17alpha-hydroxylase/C17,20-lyase with potencies 2-20-fold greater than that of ketoconazole, a previously established inhibitor of this enzyme. Derivatives of pregnane and pregnene displayed activities against 5alpha-reductase that were comparable to that of N-(1,1-dimethyl-ethyl)-3-oxo-4-aza-5alpha-androst-1-ene-17beta-car boxamide. All of the 5alpha-reductase inhibitors were able to at least partially inhibit the mitogenic effect of testosterone in either histocultures of human benign prostatic hypertrophic tissue or in cultures of the LNCaP human prostatic tumor cell line. For these compounds, it appears that this inhibition can be attributed to a reduction of DHT synthesis in these cultures, because no inhibitory effect was observed in DHT-treated cultures, and none of the compounds had a cytotoxic effect. Surprisingly, one of the inhibitors of 17alpha-hydroxylase/C17,20-lyase, 17beta-(4-imidazolyl)-5-pregnen-3beta-ol, was also able to inhibit the mitogenic effect of testosterone in both the histoculture and cell culture assays and had an effect against DHT as well. In transcriptional activation assays, it was found that this compound is an antagonist of both the wild-type androgen receptor and the mutant androgen receptor, which is present in LNCaP cells. In conclusion, the abilities of these compounds to inhibit androgen synthesis and, in some cases, to exert antiandrogen activity, did in fact translate to an inhibitory effect on the growth of human prostatic tissue in vitro, suggesting their potential utility in the treatment of prostatic cancer.