Inhibitory potency of lithocholic acid analogs and other bile acids on glucuronosyltransferase activity in a colon cancer cell line

3-Benzylaminomethyl Lithocholic Acid Derivatives Exhibited Potent and Selective Uncompetitive Inhibitory Activity Against Protein Tyrosine Phosphatase 1B (PTP1B)

Protein tyrosine phosphatase 1B (PTP1B) is a promising drug target for treating type 2 diabetes (T2DM) and obesity. As a result, developing new therapies that target PTP1B is an attractive strategy for treating these diseases. Herein, we detail the synthesis of 15 lithocholic acid (LA) derivatives, each containing different benzylaminomethyl groups attached to the C3 position of the steroid skeleton. The derivatives were assessed against two forms of PTP1B enzyme (hPTP1B1-400 and hPTP1B1-285), and the most potent compounds were then tested against T-cell protein tyrosine phosphatase (TCPTP) to determine their selectivity. The results showed that compounds 6m and 6n were more potent than the reference compounds (ursolic acid, chlorogenic acid, suramin, and TCS401). Additionally, both compounds exhibited greater potency over hPTP1B1-400. Furthermore, enzyme kinetic studies on hPTP1B1-400 revealed that these two lithocholic acid derivatives have an uncompetitive inhibition against hPTP1B1-400 with K i values of 2.5 and 3.4 μM, respectively. Interestingly, these compounds were around 75-fold more selective for PTP1B over TCPTP. Finally, docking studies and molecular dynamics simulations (MDS) were conducted to determine how these compounds interact with PTP1B. The docking studies revealed hydrophobic and H-bond interactions with amino acid residues in the unstructured region. MDS showed that these interactions persisted throughout the 200 ns simulation, indicating the crucial role of the unstructured zone in the biological activity and inhibition of PTP1B.

Synthesis and Anticancer Activity of Hybrid Molecules Based on Lithocholic and (5Z,9Z)-Tetradeca-5,9-dienedioic Acids Linked via Mono(di,tri,tetra)ethylene Glycol and α,ω-Diaminoalkane Units

For the first time, hybrid molecules were synthesized on the basis of lithocholic and (5Z,9Z)-1,14-tetradeca-5,9-dienedicarboxylic acids, obtained in two stages using the homo-cyclomagnesiation reaction of 2-(hepta-5,6-diene-1-yloxy)tetrahydro-2H-pyran at the key stage. The resulting hybrid molecules containing 5Z,9Z-dienoic acids are of interest as novel synthetic biologically active precursors to create modern drugs for the treatment of human oncological diseases. The synthesized hybrid molecules were found to exhibit extremely high in vitro inhibitory activity against human topoisomerase I, which is 2-4 times higher than that of camptothecin, a known topoisomerase I inhibitor. Using flow cytometry and fluorescence microscopy, it was first shown that these new molecules are efficient apoptosis inducers in HeLa, U937, Jurkat, K562, and Hek293 cell cultures. In addition, the results of investigations into the effect of the synthesized acids on mitochondria and studies of possible DNA damage in Jurkat tumor cells are also presented.

Synthesis of New Cisplatin Derivatives from Bile Acids

A series of bile acid derived 1,2- and 1,3-diamines as well as their platinum(II) complexes were designed and synthesized in hope to get a highly cytotoxic compound by the combination of two bioactive moieties. All complexes obtained were subjected to cytotoxicity assays in vitro and some hybrid molecules showed an expected activity.

Synthesis of steroidal 1,2- and 1,3-diamines as ligands for transition metal ion complexation

Two series of cholestane-based diamines (1,2 and 1,3) were synthesized using simple and efficient procedures. The convenient substrates for these syntheses were cholesteryl mesylate and tosylate, which were converted to appropriate amines via easily obtained azides. The final diamines were prepared using a substitution reaction with bromoacetonitrile (in the case of 1,2-diamines) or condensation with acrylonitrile (in the case of 1,3-diamines), followed by the reduction of intermediate aminonitriles. Furthermore, the other two amines were synthesized from 16-dehydropregnenolone acetate using aza-Michael addition as a key step. Some of the diamines were subjected to complexation reactions with K₂PtCl₄ to form steroidal analogs of cisplatin. The synthetic methods tested in this work will allow us to prepare other cisplatin derivatives based on steroids showing anticancer properties themselves.

Synthesis and antimicrobial properties of steroid-based imidazolium salts

Imidazolium salts reveal interesting biological properties, especially regarding antitumor and antimicrobial activities. Two series of imidazolium salts based on steroids were obtained in an efficient and convenient synthesis. They were biologically tested to evaluate their antibacterial and antifungal properties. The activities of new salts, especially in relation to Gram-positive bacterial strains are comparable to the activities of known antibiotics. The most promising activity was that against C. albicans, which exceeded the antifungal activity of commonly used drugs. Some of the new salts exhibited improved antifungal activities against phytopathogenic fungi: B. cinerea and C. beticola. Our research showed that new compounds could be potentially useful as antifungal antibiotics or inhibiting agents against pathogenic fungi.

Synthesis of dinorcholane and 5β-cholane derivatives

The convenient synthesis of seven dinorcholane and 5β-cholane derivatives, 3β-acetoxy-23,24-dinorchol-5-en-22-oyl methoxy anhydride (2), 3β-acetoxy-23,24-dinorchol-5-en-22-oyl chloride (3), 3β-acetoxy-23,24-dinorchol-5-en-22-ol (4), 3α-acetoxy-5β-cholan-24-oic acid (6), 3α-acetoxy-5β-cholan-24-oic acid ethyl ester (7), 3-oxo-5β-cholan-24-oic acid (8) and 3-oxo-5β-cholan-24-oic acid ethyl ester (9) have been described. Full spectroscopic data for these compounds are presented.

The synthesis and antitumor activity of lithocholic acid and its derivatives

In this paper, a new and concise synthetic route of lithocholic acid (LCA) using commercially available steroid source deoxycholic acid is reported. A series of amide derivatives of LCA were also synthesized and investigated for their activity against the growth of MCF-7 and MCF-7/ADR cells using the sulforhodamine B assay. For MCF-7, the most potent compound 20 showed a 20-fold higher antitumor activity than LCA. For MCF-7/ADR, the most potent compound 24 showed a 22-fold higher antitumor activity than LCA. The transwell migration assay of 20 was evaluated on MDA-MB-231 cells. The colony formation and apoptosis assays of 20 were performed on MCF-7 and MCF-7/ADR cell lines.

Lithocholic acid: a new emergent protector of intestinal calcium absorption under oxidant conditions

LCA and 1,25(OH)₂D₃ are vitamin D receptor ligands with different binding affinity. The secosteroid stimulates intestinal Ca²⁺ absorption. Whether LCA alters this process remains unknown. The aim of our work was to determine the effect of LCA on intestinal Ca²⁺ absorption in the absence or presence of NaDOC, bile acid that inhibits the cation transport. The data show that LCA by itself did not alter intestinal Ca²⁺ absorption, but prevented the inhibitory effect of NaDOC. The concomitant administration of LCA avoided the reduction of intestinal alkaline phosphatase activity caused by NaDOC. In addition, LCA blocked a decrease caused by NaDOC on gene and protein expression of molecules involved in the transcellular pathway of intestinal Ca²⁺ absorption. The oxidative stress and apoptosis triggered by NaDOC were abrogated by LCA co-treatment. In conclusion, LCA placed in the intestinal lumen protects intestinal Ca²⁺ absorption against the inhibitory effects caused by NaDOC. LCA avoids the reduction of the transcellular Ca²⁺ movement, apparently by blocking the oxidative stress and apoptosis triggered by NaDOC, normalizing the gene and protein expression of molecules involved in Ca²⁺ movement. Therefore, LCA might become a possible treatment to improve intestinal calcium absorption under oxidant conditions.

Lithocholic acid and derivatives: Antibacterial activity

In order to develop bioactive lithocholic acid derivatives, we prepared fifteen semi-synthetic compounds through modification at C-3 and/or C-24. The reactions showed yields ranging from 37% to 100%. The structures of all compounds obtained were identified on the basis of their spectral data (IR, MS, 1D- and 2D-NMR). The activity of lithocholic acid and derivatives was evaluated against the growth of Escherichia coli, Staphylococcus aureus, Bacillus cereus and Pseudomonas aeruginosa. The derivative 3α-formyloxy-5β-cholan-24-oic acid (LA-06) showed the best activity, with MIC values of 0.0790 mM against E. coli (Ec 27) and B. cereus in both cases, and 0.0395 mM against S. aureus (ATCC 12692). Lithocholic acid and the derivatives with MIC⩽1.2 mM were evaluated on the susceptibility of some bacterial pathogens to the aminoglycoside antibiotics neomycin, amikacin and gentamicin was evaluated. There are no previously reported studies about these compounds as modifiers of the action of antibiotics or any other drugs.

Calcium- and voltage-gated potassium (BK) channel activators in the 5β-cholanic acid-3α-ol analogue series with modifications in the lateral chain

Large conductance, calcium- and voltage-gated potassium (BK) channels regulate various physiological processes and represent an attractive target for drug discovery. Numerous BK channel activators are available. However, these agents usually interact with the ubiquitously distributed channel-forming subunit and thus cannot selectively target a particular tissue. We performed a structure-activity relationship study of lithocholic acid (LCA), a cholane that activates BK channels via the accessory BK β1 subunit. The latter protein is highly abundant in smooth muscle but scarce in most other tissues. Modifications to the LCA lateral chain length and functional group yielded two novel smooth muscle BK channel activators in which the substituent at C24 has a small volume and a net negative charge. Our data provide detailed structural information that will be useful to advance a pharmacophore in search of β1 subunit-selective BK channel activators. These compounds are expected to evoke smooth muscle relaxation, which would be beneficial in the pharmacotherapy of prevalent human disorders associated with increased smooth muscle contraction, such as systemic hypertension, cerebral or coronary vasospasm, bronchial asthma, bladder hyperactivity, and erectile dysfunction.