N-(1-Benzyl-3,5-dimethyl-1H-pyrazol-4-yl)benzamides: Antiproliferative Activity and Effects on mTORC1 and Autophagy

Abstract

Guided by antiproliferative activity in MIA PaCa-2 cells, we have performed preliminary structure−activity relationship studies on N-(1-benzyl-3,5-dimethyl-1H-pyrazol-4-yl)benzamides. Two selected compounds showed submicromolar antiproliferative activity and good metabolic stability. Both compounds reduced mTORC1 activity and increased autophagy at the basal level. In addition, they disrupted autophagic flux by interfering with mTORC1 reactivation and clearance of LC3-II under starvation/refeed conditions, as evidenced by accumulation of LC3-II and abnormal LC3 labeled punctae. Therefore, N-(1-benzyl-3,5-dimethyl-1H-pyrazol-4-yl)benzamides may represent a new class of autophagy modulators that possesses potent anticancer activity and potentially a novel mechanism of action.KEYWORDS: Autophagy, autophagy modulator, mTOR, pancreatic cancer, anticancer agents M acroautophagy (hereafter referred to as autophagy) is a conserved cellular process through which cytosolic components, such as proteins and organelles, are sequestered, degraded, and recycled. 1 The autophagy machinery requires a number of autophagy-related (Atg) proteins and functional complexes, including the UNC51-like kinase 1 (ULK1) complex, the class III phosphoinositide 3-kinase (PI3K) complex, the Atg12-Atg5-Atg16 ubiquitin-like conjugation system, and the microtubule-associated protein light chain 3 (LC3)-phosphatidylethanolamine (PE) conjugation system. Among these autophagy components, LC3-II, which is the PE lipidated form of LC3-I, plays a key role. LC3-II is generated after a series of processing by the Atg4-Atg7-Atg3 conjugation machinery. Since it is closely involved in autophagy, the level of LC3-II is commonly used as a marker to monitor autophagy. 2 Autophagy is regulated by a network of complex signaling pathways, where the class I phosphatidylinositol 3-kinase-AKTmammalian target of rapamycin complex 1 (PI3K-AKTmTORC1) pathway is a well-established negative regulator. While a basal level of autophagy is required to maintain cellular homeostasis, it is upregulated in response to lack of nutrients, unfavorable energy status, attenuated growth signaling, virus/ bacteria invasion, and a number of cellular stresses including endoplasmic reticulum stress, oxidative stress, and hypoxia. 3 Activation of autophagy is generally accomplished by inhibiting mTORC1, which in turn increases autophagy by unblocking ULK1. In addition to its role in autophagy, mTORC1 also phosphorylates and regulates substrates including ribosomal protein S6 kinase beta-1 (P70S6K1, hereafter referred to as P70) and 4E-binding protein 1 (4EBP1), and levels of phosphorylated substrates are routinely used to gauge mTORC1 activity.The precise role of autophagy in tumorigenesis and cancer therapy still remains to be defined due to the heterogeneous nature of cancers and the complexity of the autophagy machinery. 4 Studies have shown that autophagy plays different or even opposite roles depending on the cancer type and the stage of tumor progression. Currently, it is ...

In silico evaluation and docking studies of pyrazole analogs as potential autophagy modulators against pancreatic cancer cell line MIA PaCa-2

“…A data set comprised of nineteen N-(1-benzyl-3,5-dimethyl-1H-pyrazole-4-yl) benzamide derivatives was used in the present study. All compounds and associated data were obtained from literature [22]. The biological activity data were reported as (EC50) values half maximal effective concentration in MIA PaCa-2a pancreatic cancer line.…”

Synthesis and structure-activity relationships of new pyrazole derivatives that induce triple response in <i>Arabidopsis</i> seedlings

“…was prepared using a method previously described. 21) Methylamine-HCl (25 mmol) and paraformaldehyde (30 mM, 6 eq) were combined in absolute EtOH (0.5 M) and was heated for 2 hr at 60°C. At this point, the 3,5-dimethyl-1-phenylpyrazole (1.15 g, 5 mmol) was added, and the reaction was heated to 75°C and stirred for 10 hr.…”

“…Then pyrazole (5 mmol) was added and warmed at 75°C (10 hr). 21) b: Benzenesulfonyl chloride was added to a methylene chloride solution of trimethylamine, and compound B (1 eq) was added and stirred at room temperature for 12 hr. 19) 2.3±0.1 mm (the black bar), while the root length of ethephontreated (10 µM) Arabidopsis seedlings was found to be approximately 1.0±0.1 mm (the white bar).…”

Products of interaction of substituted 5-aminopyrazoles with α -haloketones as potential pharmaceutical agents

“…graminis [6], Aspergillus niger [3]). Pyrazoles are known to possess numerous chemical and biological activities such as anti inflammatory [7], antiproliferative [8], antiepileptic [9].…”