Novel anticancer Hsp90 inhibitor disubstituted pyrazolyl 2-aminopyrimidine compound 7t induces cell cycle arrest and apoptosis via mitochondrial pathway in MCF-7 cells.

Compound 7t, 4-(4-bromophenyl)-6-(1-(4-chlorophenyl)-3-(4-nitrophenyl)-1H-pyrazol-4-yl) pyrimidin-2-amine, is a proven potent anticancer agent exhibiting Hsp90 inhibition in our previous studies. Herein, we explored the apoptotic potential of compound 7t by Annexin V assay. The mechanism underlining the apoptosis process is elucidated. As a potent Hsp90 inhibitor, compound 7t would induce the mitochondrial stress leading to increased permeability of its membrane, that would subsequently initiate the apoptosis in MCF-7 cells. This was proven by increased J-monomer formation using JC-1 stain. Moreover, due to the impaired mitochondrial function, compound 7t also exaggerated the apoptosis process by ROS generation as proved by DCFDA staining. The morphological and nuclear changes in MCF-7 cells following apoptosis were identified by AO/EB and DAPI staining techniques. It also induced subG1 phase cell cycle arrest. Thus, compound 7t could serve as potential drug in the treatment regimen of breast cancer.

Mechanistic investigations on substituted benzene sulphonamides as apoptosis inducing anticancer agents.

In an approach to develop potent cytotoxic compounds with targeted action, a systematic methodology was employed to design and initially synthesize parent compounds A1, A8, A13 and A14 followed by synthesis of further analogs of A1 (A2-A7) and A8 (A9-A12) with characterization by IR, NMR, mass and elemental techniques. These compounds were evaluated for their in vitro anti-proliferative activities against DU-145, MCF-7, HCT-15, HT-29 cell lines and apoptosis inducing potential via various mechanistic studies. Compounds A2, A9, A10 exhibited significant cytotoxic activities compared to their parent compounds and standard drug 5-fluorouracil. Compound A2 displayed superior cytotoxicity with IC50 values less than 1 µM in most of the tested cell lines. Further, compound A2 also induced apoptosis in DU-145 cells as exemplified from DAPI staining, Annexin V-FITC assay, ROS generation and mitochondrial membrane alteration studies. The above studies depict the synthesized compound A2 as potent anticancer agent with the ability to induce apoptosis in prostate cancerous cells.

Design, synthesis, and molecular docking studies of novel pyrazolyl 2-aminopyrimidine derivatives as HSP90 inhibitors.

A series of novel pyrazolyl 2-aminopyrimidine derivatives (7a-t) were designed based on scaffold hopping techniques, synthesized and biologically evaluated for their HSP90 inhibition and anticancer activity. Several compounds exhibited potent HSP90 inhibition with IC50 values less than that of the reference standard 17-AAG (1.25 µM). The most potent compound 7t displayed excellent HSP90 inhibition with an IC50 of 20 nM and in vitro antiproliferative potential against three cancer cell lines (IC50 < 5 µM). 7t also induced dose dependent degradation of client proteins (pHER2 and pERK1/2) in Western blot analysis. Several structural features of 7p-t oriented the molecules to retain all the essential binding interactions with HSP90, as observed by rationalized docking studies. Therefore, the para-nitrophenyl ring on the central pyrazole ring along with the 2-amino group on the pyrimidine ring are the crucial features in the development of novel HSP90 inhibitors based on this scaffold for targeted anticancer therapy.

Dual or multi-targeting inhibitors: The next generation anticancer agents.

Dual-targeting/Multi-targeting of oncoproteins by a single drug molecule represents an efficient, logical and alternative approach to drug combinations. An increasing interest in this approach is indicated by a steady upsurge in the number of articles on targeting dual/multi proteins published in the last 5 years. Combining different inhibitors that destiny specific single target is the standard treatment for cancer. A new generation of dual or multi-targeting drugs is emerging, where a single chemical entity can act on multiple molecular targets. Dual/Multi-targeting agents are beneficial for solving limited efficiencies, poor safety and resistant profiles of an individual target. Designing dual/multi-target inhibitors with predefined biological profiles present a challenge. The latest advances in bioinformatic tools and the availability of detailed structural information of target proteins have shown a way of discovering multi-targeting molecules. This neoteric artifice that amalgamates the molecular docking of small molecules with protein-based common pharmacophore to design multi-targeting inhibitors is gaining great importance in anticancer drug discovery. Current review focus on the discoveries of dual targeting agents in cancer therapy using rational, computational, proteomic, bioinformatics and polypharmacological approach that enables the discovery and rational design of effective and safe multi-target anticancer agents.