Identification of Novel Class of Triazolo-Thiadiazoles as Potent Inhibitors of Human Heparanase and their Anticancer Activity.

BACKGROUND: Expression and activity of heparanase, an endoglycosidase that cleaves heparan sulfate (HS) side chains of proteoglycans, is associated with progression and poor prognosis of many cancers which makes it an attractive drug target in cancer therapeutics. METHODS: In the present work, we report the in vitro screening of a library of 150 small molecules with the scaffold bearing quinolones, oxazines, benzoxazines, isoxazoli(di)nes, pyrimidinones, quinolines, benzoxazines, and 4-thiazolidinones, thiadiazolo[3,2-a]pyrimidin-5-one, 1,2,4-triazolo-1,3,4-thiadiazoles, and azaspiranes against the enzymatic activity of human heparanase. The identified lead compounds were evaluated for their heparanase-inhibiting activity using sulfate [35S] labeled extracellular matrix (ECM) deposited by cultured endothelial cells. Further, anti-invasive efficacy of lead compound was evaluated against hepatocellular carcinoma (HepG2) and Lewis lung carcinoma (LLC) cells. RESULTS: Among the 150 compounds screened, we identified 1,2,4-triazolo-1,3,4-thiadiazoles bearing compounds to possess human heparanase inhibitory activity. Further analysis revealed 2,4-Diiodo-6-(3-phenyl-[1, 2, 4]triazolo[3,4-b][1, 3, 4]thiadiazol-6yl)phenol (DTP) as the most potent inhibitor of heparanase enzymatic activity among the tested compounds. The inhibitory efficacy was demonstrated by a colorimetric assay and further validated by measuring the release of radioactive heparan sulfate degradation fragments from [35S] labeled extracellular matrix. Additionally, lead compound significantly suppressed migration and invasion of LLC and HepG2 cells with IC50 value of ~5 μM. Furthermore, molecular docking analysis revealed a favourable interaction of triazolo-thiadiazole backbone with Asn-224 and Asp-62 of the enzyme. CONCLUSIONS: Overall, we identified biologically active heparanase inhibitor which could serve as a lead structure in developing compounds that target heparanase in cancer

Novel Adamantanyl-Based Thiadiazolyl Pyrazoles Targeting EGFR in Triple-Negative Breast Cancer.

The epidermal growth factor receptor (EGFR) is a validated therapeutic target for triple-negative breast cancer (TNBC). In the present study, we synthesize novel adamantanyl-based thiadiazolyl pyrazoles by introducing the adamantane ring to thiazolopyrazoline. On the basis of loss of cell viability in TNBC cells, 4-(adamantan-1-yl)-2-(3-(2,4-dichlorophenyl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl)thiazole (APP) was identified as a lead compound. Using a Parzen-Rosenblatt Window classifier, APP was predicted to target the EGFR protein, and the same was confirmed by surface plasmon resonance. Further analysis revealed that APP suppressed the phosphorylation of EGFR at Y992, Y1045, Y1068, Y1086, Y1148, and Y1173 in TNBC cells. APP also inhibited the phosphorylation of ERK at Y204 and of STAT3 at Y705, implying that APP downregulates the activity of EGFR downstream effectors. Small interfering RNA mediated depletion of EGFR expression prevented the effect of APP in BT549 and MDA-MB-231 cells, indicating that APP specifically targets the EGFR. Furthermore, APP modulated the expression of the proteins involved in cell proliferation and survival. In addition, APP altered the expression of epithelial-mesenchymal transition related proteins and suppressed the invasion of TNBC cells. Hence, we report a novel and specific inhibitor of the EGFR signaling cascade

MIC values obtained from the lead AIT compounds against <i>A</i>. <i>fumigates</i>, which expresses CYP51.

<p>Given the activity of compounds in this system this finding corroborates CYP51 as a plausible target of the AIT series.</p

Computational binding mode analysis of AITs and <i>M</i>. <i>tubercolosis</i> CYP51.

<p>A) X-ray structure of CYP51 (green cartoon representation with heme cofactor as sticks with bound iron as brown sphere) in complex with a small molecule inhibitor (PDB: 2CIB). B) Similar interactions and an analogous three-dimensional arrangement are shown for compound <b>3f</b> of the AITs (cyan sticks). C) Overlay of the parent 1,3,4-thiadiazole of Oruc et al [Oruc04] with compound <b>3a</b> of the AITs. Positioning of ring centers, exit vectors, and overall shape are very similar, thereby plausibly explaining a similar bioactivity profile.</p

A) Schematic representation of the preparation of AITs. B) ORTEP diagram of 3b.

<p>The compound crystallizes in a triclinic system under the space group P-1, and the benzyl imidazothiadiazole moiety adopts a chair conformation with the benzyl imidazothiadiazole moiety and the phenyl ring being bridged by the carbon atom (C6) with a dihedral angle of 69.73 degrees.</p

Cyclocondensation of 5-alkyl/aryl-2-amino-1,3,4-thiadiazole (1a-j) with 1-adamantyl bromomethylketone to form (3a-j).

<p>Equimolar mixture of <b>1a-j</b>, and <b>2</b> was dissolved in 2 ml of [BMIM]⁺[BF₄]^- and the reaction was carried out in the presence of 0.1 equivalent of <b>Nano</b> MgO at 60 ⁰C.</p><p>Cyclocondensation of 5-alkyl/aryl-2-amino-1,3,4-thiadiazole (1a-j) with 1-adamantyl bromomethylketone to form (3a-j).</p