Efficient Preparation of [2-13C]- and [3-13C]-3-Cyano-4-methyl-3-pyrrolin-2-one

4-Methyl-5-(4-nitro-benzyl-idene)-2-oxo-2,5-di-hydro-1H-pyrrole-3-carbo-nitrile

Mol-ecules of the potential non-linear optical title compound, C13H9N3O3, form dimeric stacks of mol-ecules along the a axis cross-linked around inversion centers by N-H⋯O hydrogen bonds and weak (phen-yl)C-H⋯O inter-molecular inter-actions, forming a 'collaboration' of R 2 (2)(8) and R 2 (2)(16) ring motifs. The mol-ecules are then further linked by weak C-H⋯O and C-H⋯N inter-actions into sheets parallel to (121).

The selective inhibitory effect of a synthetic tanshinone derivative on prostate cancer cells

BACKGROUND

Androgen receptor (AR) is the main therapeutic target for the treatment of prostate cancer (PCa). Anti-androgens to reduce or prevent androgens binding to AR are widely used to suppress AR-mediated PCa growth; however, the androgen depletion therapy (ADT) is only effective for a short period of time. Here we tested PTS33, a new sodium derivative of cryptotanshinone, which can effectively inhibit the DHT-induced AR transactivation and PCa cell growth, and then explored the effects of PTS33 on inhibiting the expressions of AR target genes and proteins.

METHODS

PCa cells, LNCaP, CWR22Rv1, C4-2, PC-3, and DU145, were treated with PTS33 and luciferase assay was used to evaluate the ability of each to regulate AR transactivation. RT-PCR was used to evaluate the mRNA levels of AR target genes such as PSA, TMPRSS2, and TMEPA1. Western blot was used to determine AR, PSA, estrogen receptor alpha (ERα), glucocorticoid receptor (GR), and progesterone receptor (PR) protein expression. Cell growth and IC50 were determined by MTT assay after 48 hr treatment.

RESULTS

Our data showed that PTS33 selectively inhibits AR activities, but PTS33 does not repress the activities of other nuclear receptors, including ERα, GR, and PR. At a low concentration, 2 µM of PTS33 effectively suppresses the growth of AR-positive PCa cells, and has little effect on AR-negative PCa cells. Furthermore, our data indicated that PTS33 could modulate AR transactivation and suppress the AR target genes (PSA, TMPRSS2, and TMEPA1) expression in both androgen responsive PCa LNCaP cells and castration-resistant C4-2 cells. In addition, PTS33 can also inhibit estrogen/Δ5-androstenediol induced AR activities. The mechanistic studies indicate that PTS33 can inhibit AR function by suppression of AR protein expression, the AR N-C interaction, and AR-coregulator interaction.

CONCLUSIONS

PTS33 has shown a good efficacy to inhibit AR transactivation, block AR regulated gene expression, and reduce cell growth in AR positive PCa cells. The structure of PTS33 could be used as a base for development of novel AR signaling inhibitors to treat PCa.

The role of the chromophore in the biological photoreceptor phytochrome: an approach using chemically synthesized tetrapyrroles

In plants and bacteria, phytochromes serve as light-inducible, red-/far-red light sensitive photoreceptors that control a wide range of photomorphogenetic processes. Phytochromes comprise a protein moiety and a covalently bound bilin chromophore. Bilins are open-chain tetrapyrrole compounds that derive biosynthetically from ubiquitous porphyrins. The investigations of phytochromes reveal that precise interactions between the protein moiety and its bilin chromophore are essential for the proper functioning of this photoreceptor; accordingly, synthetic manipulation of the parts is an important method for studying the whole. Although variations in the protein structure are readily accomplished by routine mutagenesis protocols, the generation of structurally modified bilins is a laborious, multistep process. Recent improvement in the synthesis of open-chain tetrapyrroles now permits the generation of novel, structurally modified (and even selectively isotope-labeled) chromophores. Furthermore, by using the capability of recombinant apo-phytochrome to bind the chromophore autocatalytically, researchers can now generate novel chromoproteins with modified functions. In the protein-bound state, the phytochrome chromophore is photoisomerized at one double bond, in the bridge between the last two of the four pyrrole rings (the C and D rings), generating the thermally stable, physiologically active P(fr) form. This conversion--photoisomerization from the form absorbing red light (P(r)) to the form absorbing far-red light (P(fr))--covers 12 orders of magnitude, from subpicoseconds to seconds. Such spectroscopic and kinetic studies yield a wealth of time-resolved spectral data, even more so, if proteins with changed sequence or chromophore structure are utilized. In particular, bilins with a changed substitution pattern at the photoisomerizing ring D have shed light on the chromophore-protein interactions during the photoisomerization. The mechanisms generating and stabilizing the light-induced P(fr) form of phytochromes are now seen in greater detail. On the other hand, the use of bilins with selective incorporation of stable isotopes identify light-induced conformational motions when studied by vibrational (FTIR and Raman) and NMR spectroscopy. In this Account, we present spectroscopic investigations that provide structural details in these biological photoreceptors with great precision and document the dynamics elicited by light excitation. This approach yields important information that complements the data deduced from crystal structure.

Synthesis and use of stable isotope enriched retinals in the field of vitamin A

The role of vitamin A and its metabolites in the life processes starting with the historical background and its up to date information is discussed in the introduction. Also the role of 11Z-retinal in vision and retinoic acid in the biological processes is elucidated. The essential role of isotopically enriched systems in the progress of vision research, nutrition research etc. is discussed. In part B industrial commercial syntheses of vitamin A by the two leading companies Hoffmann-La Roche (now DSM) and BASF are discussed. The knowledge obtained via these pioneering syntheses has been essential for the further synthetic efforts in vitamin A field by other scientific groups. The rest of the paper is devoted to the synthetic efforts of the Leiden group that gives an access to the preparation of site directed high level isotope enrichment in retinals. First the synthesis of the retinals with deuterium incorporation in the conjugated side chain is reviewed. Then, 13C-labeled retinals are discussed. This is followed by the discussion of a convergent synthetic scheme that allows a rational access to prepare any isotopomer of retinals. The schemes that provide access to prepare any possible isotope enriched chemically modified systems are discussed. Finally, nor-retinals and bridged retinals that give access to a whole (as yet incomplete) library of possible isotopomers are reviewed.