Synthesis of new arylazopyrazoles as apoptosis inducers: Candidates to inhibit proliferation of MCF-7 cells

Current scenario of pyrazole hybrids with anti-breast cancer therapeutic applications

Breast cancer stands as the leading cause of cancer-related deaths among women globally, but current therapy is restricted to the serious adverse effects and multidrug resistance, necessitating the exploration of novel, safe, and efficient anti-breast cancer chemotherapeutic agents. Pyrazoles exhibit excellent potential for utilization as effective anti-breast cancer agents due to their ability to act on various biological targets. Particularly, pyrazole hybrids demonstrated the advantage of targeting multiple pathways, and some of them, which are exemplified by larotrectinib (pyrazolo[1,5-a]pyrimidine hybrid), can be applied for breast cancer therapy. Thus, pyrazole hybrids hold great promise as useful therapeutic interventions for breast cancer. The aim of this review is to summarize the current scenario of pyrazole hybrids with in vitro and/or in vivo anti-breast cancer potential, along with the modes of action and structure-activity relationships, covering articles published from 2020 to the present, to streamline the development of rational, effective and safe anti-breast cancer candidates.

Laccase-mediated chemoselective C-4 arylation of 5-aminopyrazoles

Chemoselective arylation of 5-aminopyrazoles was performed through oxidative formation of orthoquinones from catechols catalyzed by Myceliophthora thermophila laccase (Novozym 51003), and subsequently nucleophilic attack of 5-aminopyrazole to the catechol intermediates. The C-4 arylated products were obtained under extremely mild conditions without the need for amine protection or halogenation of the substrates. From this method, 10 derivatives with moderate to good efficiency (42-94%) were prepared.

Novel quinoxaline-3-propanamides as VGFR-2 inhibitors and apoptosis inducers

Vascular endothelial growth factor receptor-2 is a vital target for therapeutic mediation in various types of cancer. This study was aimed at exploring the cytotoxic activity of seventeen novel quinoxaline-3-propanamides against colon cancer (HCT-116) and breast cancer (MCF-7) using MTT assay. Results revealed that compounds 8, 9, and 14 elicited higher cytotoxicity than the reference drugs, doxorubicin (DOX) and sorafenib. Interestingly, they are more selective for HCT-116 (SI 11.98-19.97) and MCF-7 (SI 12.44-23.87) compared to DOX (SI HCT-116 0.72 and MCF-7 0.9). These compounds effectively reduced vascular endothelial growth factor receptor-2; among them, compound 14 displayed similar VEGFR-2 inhibitory activity to sorafenib (IC50 0.076 M). The ability of 14 to inhibit angiogenesis was demonstrated by a reduction in VEGF-A level compared to control. Furthermore, it induced a significant increase in the percentage of cells at pre-G1 phase by almost 1.38 folds (which could be indicative of apoptosis) and an increase in G2/M by 3.59 folds compared to the control experiment. A flow cytometry assay revealed that compound 14 triggered apoptosis via the programmed cell death and necrotic pathways. Besides, it caused a remarkable increase in apoptotic markers, i.e., caspase-3 p53 and BAX. When compared to the control, significant increase in the expression levels of caspase-3 from 47.88 to 423.10 and p53 from 22.19 to 345.83 pg per ml in MCF-7 cells. As well, it increased the proapoptotic protein BAX by 4.3 times while lowering the antiapoptotic marker BCL2 by 0.45 fold. Docking studies further supported the mechanism, where compound 14 showed good binding to the essential amino acids in the active site of VEGFR-2. Pharmacokinetic properties showed the privilege of these hits over sunitinib: they are not substrates of P-gp protein; this suggests that they have less chance to efflux out of the cell, committing maximum effect; and in addition, they do not allow permeation to the BBB.

Novel quinoxaline-based VEGFR-2 inhibitors to halt angiogenesis

Vascular endothelial growth factor receptor-2 is a dynamic target for therapeutic intervention in various types of cancer. This study was aimed at exploring the VEGFR-2 inhibitory activity of a novel library of quinoxalin-2-one derivatives such as 3-furoquinoxaline carboxamides, 3-pyrazolylquinoxalines, and 3-pyridopyrimidyl-quinoxalines. Among them, 6c, 7a, and 7d-f produced remarkable cytotoxicity against HCT-116 (IC50's 4.28-9.31 µM) and MCF-7 (IC50's 3.57-7.57 µM) cell lines using the MTT assay and doxorubicin (DOX) as a reference standard. Interestingly, results of cytotoxicity towards the human fibroblast cell line WI38 revealed that these hits demonstrated higher selectivity indices towards both HCT-116 (SI 8.69-23.19) and MCF-7 (SI 9.48-27.80) than DOX, SI 0.72 and 0.90, respectively. Then, these hits were subjected to a mechanistic study; they showed direct inhibition of VEGFR-2. Impressively, compound 7f displayed 1.2 times the VEGFR-2 inhibitory activity of sorafenib. The antiangiogenic potential of 7f was proved via lowering the level of VEGF-A, than that of control. It as well, exhibited scratch closure percent of 61.8%, compared with 74.5% of control at 48 hrs, indicating the potential anti-migratory effect of the compound 7f. It significantly increased the expression of tumor suppressor gene (p53) on MCF-7 cells by almost 18 folds and upregulated the caspase-3 level by 10.7 folds, compared to the control. Cell cycle analysis revealed cell cycle arrest at G2/M together with a PreG increase which indicated apoptosis induction potential. Annexin V-FITC apoptosis results proposed the two modes of cell death (apoptosis and necrosis) as an inherent mechanism of cytotoxicity of compound 7f. Molecular docking further supported the mechanism showing the affinity of target compounds for VEGFR-2 active site. Moreover, physicochemical and drug-like properties were assessed from the ADME properties.

Amino-Pyrazoles in Medicinal Chemistry: A Review

A pyrazole nucleus is an easy-to-prepare scaffold with large therapeutic potential. Consequently, the search for new pyrazole-based compounds is of great interest to the academic community as well as industry. In the last ten years, a large number of papers and reviews on the design, synthesis, and biological evaluation of different classes of pyrazoles and many pyrazole-containing compounds have been published. However, an overview of pyrazole derivatives bearing a free amino group at the 3, 4, or 5 position (namely, 3-aminopyrazoles, 4-aminopyrazoles, and 5-aminopyrazoles, respectively) and their biological properties is still missing, despite the fact that aminopyrazoles are advantageous frameworks able to provide useful ligands for receptors or enzymes, such as p38MAPK, and different kinases, COX and others, as well as targets important for bacterial and virus infections. With the aim to fill this gap, the present review focuses on aminopyrazole-based compounds studied as active agents in different therapeutic areas, with particular attention on the design and structure-activity relationships defined by each class of compounds. In particular, the most relevant results have been obtained for anticancer/anti-inflammatory compounds, as the recent approval of Pirtobrutinib demonstrates. The data reported here are collected from different databases (Scifinder, Web of Science, Scopus, Google Scholar, and Pubmed) using "aminopyrazole" as the keyword.

The anticancer and EGFR-TK/CDK-9 dual inhibitory potentials of new synthetic pyranopyrazole and pyrazolone derivatives: X-ray crystallography, in vitro, and in silico mechanistic investigations

Treatment options for the management of breast cancer are still inadequate. This inadequacy is attributed to the lack of effective targeted medications, often resulting in the recurrence of metastatic disorders. Cumulative evidence suggests that epidermal growth factor receptor (EGFR-TK) and cyclin-dependent kinases-9 (CDK-9) overexpression correlates with worse overall survival in breast cancer patients. Pyranopyrazole and pyrazolone are privileged options for the development of anticancer agents. Inspired by this proven scientific fact, we report here the synthesis of two new series of suggested anticancer molecules incorporating both heterocycles together with their characterization by IR, 1H NMR, 13C NMR, 13C NMR-DEPT, and X-ray diffraction methods. An attempt to get the pyranopyrazole-gold complexes was conducted but unexpectedly yielded benzylidene-2,4-dihydro-3H-pyrazol-3-one instead. This unexpected result was confirmed by X-ray crystallographic analysis. All newly synthesized compounds were assessed for their anti-proliferative activity against two different human breast cancer cells, and the obtained results were compared with the reference drug Staurosporine. The target compounds revealed variable cytotoxicity with IC50 at a low micromolar range with superior selectivity indices. Target enzyme EGFR-TK and CDK-9 assays showed that compounds 22 and 23 effectively inhibited both biological targets with IC50 values of 0.143 and 0.121 µM, respectively. Molecular docking experiments and molecular dynamics simulation were also conducted to further rationalize the in vitro obtained results.Communicated by Ramaswamy H. Sarma.

A review on the role of cyclin dependent kinases in cancers

The Cyclin-dependent kinase (CDK) class of serine/threonine kinases has crucial roles in the regulation of cell cycle transition and is mainly involved in the pathogenesis of cancers. The expression of CDKs is controlled by a complex regulatory network comprised of genetic and epigenetic mechanisms, which are dysregulated during the progression of cancer. The abnormal activation of CDKs results in uncontrolled cancer cell proliferation and the induction of cancer stem cell characteristics. The levels of CDKs can be utilized to predict the prognosis and treatment response of cancer patients, and further understanding of the function and underlying mechanisms of CDKs in human tumors would pave the way for future cancer therapies that effectively target CDKs. Defects in the regulation of cell cycle and mutations in the genes coding cell-cycle regulatory proteins lead to unrestrained proliferation of cells leading to formation of tumors. A number of treatment modalities have been designed to combat dysregulation of cell cycle through affecting expression or activity of CDKs. However, effective application of these methods in the clinical settings requires recognition of the role of CDKs in the progression of each type of cancer, their partners, their interactions with signaling pathways and the effects of suppression of these kinases on malignant features. Thus, we designed this literature search to summarize these findings at cellular level, as well as in vivo and clinical levels.