Anticancer activity of novel steroidal 6-substituted 4-en-3-one D-seco dinitriles.

Steroidal 16,17-seco-16,17a-dinitriles possessing 4-ene-3,6-dione (3), 6-methylene-4-en-3-one (5), (6E)-hydroxyimino-4-en-3ß-ol (9) or (6E)-hydroxyimino-4-en-3-one (10) moiety were synthesized starting from 3ß-acetoxy-16,17-secoandrost-4-ene-16,17a-dinitrile (1). Antiproliferative activity of the newly synthesized compounds, as well as previously synthesized 3-oxo-16,17-secoandrosta-1,4-diene-16,17a-dinitrile (VII), was tested in vitro. Compound 9 displayed submicromolar antiproliferative activity against human cervical carcinoma (HeLa) cells (IC50 0.48 µM), and compounds 3 and 10 expressed strong inhibitory potential against HeLa cells (IC50 4.31 µM and 2.64 µM, respectively). Also, compound 10 was effective in inhibiting estrogen hormone-independent (MDA-MB-231) cells (IC50 2.78 µM). All tested compounds had no influence on the proliferation of healthy cells (MRC-5). Since MDA-MB-231 breast cancer cells and HeLa cervical cancer cells were most sensitive to treatment by 16,17-seco-16,17a-dinitriles, apoptosis induction after treatment by compounds 3, VII, 9 and 10 was studied in these cells, to reveal the mechanism underlying cell growth inhibition. All tested compounds significantly induced apoptosis in both treated cell lines, which was evident from results obtained by a double AO-EB staining test and quantified by counting cells with apoptotic morphology after staining with Giemsa dye. Among all tested substances, (6E)-hydroxyimino-4-en-3-one derivative 10 expressed the most proapoptotic activity.

Androstane derivatives induce apoptotic death in MDA-MB-231 breast cancer cells.

Biological investigation was conducted to study in vitro antiproliferative and pro-apoptotic potential of selected 17α-picolyl and 17(E)-picolinylidene androstane derivatives. The antiproliferative impact was examined on six human tumor cell lines, including two types of breast (MCF-7 and MDA-MB-231), prostate (PC3), cervical (HeLa), colon (HT 29) and lung cancer (A549), as well as one normal fetal lung fibroblasts cell line (MRC-5). All derivatives selectively decreased proliferation of estrogen receptor negative MDA-MB-231 breast cancer cells after 48 h and 72 h treatment and compounds showed time-dependent activity. We used this cell line to investigate cell cycle modulation and apoptotic cell death induction by flow cytometry, expression of apoptotic proteins by Western blot and apoptotic morphology by visual observation. Tested androstane derivatives affected the cell cycle distribution and induced apoptosis and necrosis. Compounds had different and specific mode of action, depending on derivative type and exposure time. Some compounds induced significant apoptosis measured by Annexin V test compared to reference compound formestane. Higher expression of pro-apoptotic BAX, downregulation of anti-apoptotic Bcl-2 and cleavage of PARP protein were confirmed in almost all treated samples, but the lack of caspase-3 activation suggested the induction of apoptosis in caspase-independent manner. More cells with apoptotic morphology were observed in samples after prolonged treatment. Structure-activity relationship analysis was performed to find correlations between the structure variations of investigated derivatives and observed biological effects. Results of this study showed that some of the investigated androstane derivatives have good biomedical potential and could be candidates for anticancer drug development.

Synthesis, structural analysis and antitumor activity of novel 17α-picolyl and 17(E)-picolinylidene A-modified androstane derivatives.

The heterocyclic ring at C-17 position of the androstane compounds plays an important role in biological activity. The aim of the present study was to synthesize and evaluate potential antitumor activity of different A-modified 17α-picolyl and 17(E)-picolinylidene androstane derivatives. In several synthetic steps, novel derivatives bearing the hydroximino, nitrile or lactame functions in A-ring were synthesized and characterized according to the spectral data, by mass analysis as well as XRD analysis (compounds 6, 13 and 15). The structurally most promising compounds 6, 11-17 were investigated as antitumor agents. The in vitro antiproliferative activity was evaluated against six human cancer cell lines: estrogen receptor negative (ER-) breast adenocarcinoma (MDA-MB-231); estrogen receptor positive (ER+) breast adenocarcinoma (MCF-7); prostate cancer (PC-3); human cervical carcinoma (HeLa); lung adenocarcinoma (A549) and colon adenocarcinoma (HT-29) using MTT assay. The results of the 48h incubation time in vitro tests showed that compound 15 was the most effective against PC-3 (IC50 6.6µM), compound 17 against MCF-7 (IC50 7.9µM) cells, while compound 16 exhibited strong antiproliferative effect against both, MCF-7 (IC50 1.7µM) and PC-3 (IC50 8.7µM) cancer cells. It was also found that compounds 16 and 17 induced apoptosis in MCF-7 cells (dicyano derivative 17 stronger then dioxime 16 and reference formestane), with no distinct changes in the cell cycle of MCF-7 cells.