Improved synthesis, resolution, absolute configuration determination and biological evaluation of HLM006474 enantiomers.

An improved green synthesis of the E2F inhibitor HLM0066474 is described, using solvent-free and microwave irradiation conditions. The two enantiomers are separated using semi-preparative separation on Chiralpak ID and their absolute configuration is determined by vibrational circular dichroism (VCD) analysis. Biological evaluation of both enantiomers on E2F1 transcriptional activity reveals that the (+)-R, but not the (-)-S enantiomer is biologically active in repressing E2F1 transcriptional activity.

E2F1 inhibition mediates cell death of metastatic melanoma.

Melanoma is one of the most lethal cancers when it reaches a metastatic stage. Despite advancements in targeted therapies (BRAF inhibitors) or immunotherapies (anti-CTLA-4 or anti-PD1), most patients with melanoma will need additional treatment. Thus, there is an urgent need to develop new therapeutical approaches to bypass resistance and achieve more prolonged responses. In this context, we were interested in E2F1, a transcription factor that plays a major role in the control of cell cycle under physiological and pathological conditions. Here we confirmed that E2F1 is highly expressed in melanoma cells. Inhibition of E2F1 activity further increased melanoma cell death and senescence, both in vitro and in vivo. Moreover, blocking E2F1 also induced death of melanoma cells resistant to BRAF inhibitors. In conclusion, our studies suggest that targeting the E2F1 signaling pathway may be therapeutically relevant for melanoma.

Synthesis of 1,4-disubstituted 1,2,3-triazole Derivatives Using Click Chemistry and their Src Kinase Activities.

BACKGROUND: Tyrosine kinases (TK) are enzymes that catalyze the phosphorylation of tyrosine residues on proteins by the transfer of phosphate moiety of ATP. TK are key regulators of various cell functions, such as cellular growth, proliferation, migration, differentiation, and apoptosis. Src mutations and/or overexpression has been correlated with tumor growth, metastasis, and angiogenesis [4,5]. Thus, the design and the discovery of novel Src kinase inhibitors remains critically important. METHODS: A series of 1,4-disubstituted 1,2,3-triazoles derivatives were designed and prepared as potential inhibitors for Src kinase. In this manuscript, all of the designed compounds were screened via molecular docking using PLANTS as virtual screening software to identify new inhibitors of Src kinase. Subsequently, all of the screened compounds were synthesized via Huisgen's 1,3-dipolar cycloaddition between terminal alkynes (1) and methyl 2-azidoacetate (2) with Cu(I) in excellent yields at room temperature. RESULTS: In the present study, we report the design and the synthesis of a series of 1,4-disubstituted 1,2,3-triazoles involving one pot condensation of methyl 2-azidoacetate and different terminal alkynes. All the synthesized triazoles were characterized by IR, 1 H, 13 C, 19 F NMR, and HRMS. They were investigated as inhibitors of Src kinase. CONCLUSION: A series of 1,4-disubstituted 1,2,3-triazole compounds were synthesized through an easy, convenient Cu(I) catalyzed click reaction and evaluated for their Src kinase activity. Compound 3m exhibited significant inhibitory activity against Src Kinase. These results, along with molecular design docking observations, are significant evidence to demonstrate the compound 3m could be optimized as a potential Src kinase inhibitor in further studies.

The Rational Design, Synthesis, and Antimicrobial Properties of Thiophene Derivatives That Inhibit Bacterial Histidine Kinases.

The emergence of multidrug-resistant bacteria emphasizes the urgent need for novel antibacterial compounds targeting unique cellular processes. Two-component signal transduction systems (TCSs) are commonly used by bacteria to couple environmental stimuli to adaptive responses, are absent in mammals, and are embedded in various pathogenic pathways. To attenuate these signaling pathways, we aimed to target the TCS signal transducer histidine kinase (HK) by focusing on their highly conserved adenosine triphosphate-binding domain. We used a structure-based drug design strategy that begins from an inhibitor-bound crystal structure and includes a significant number of structurally simplifiying "intuitive" modifications to arrive at the simple achiral, biaryl target structures. Thus, ligands were designed, leading to a series of thiophene derivatives. These compounds were synthesized and evaluated in vitro against bacterial HKs. We identified eight compounds with significant inhibitory activities against these proteins, two of which exhibited broad-spectrum antimicrobial activity. The compounds were also evaluated as adjuvants for the treatment of resistant bacteria. One compound was found to restore the sensivity of these bacteria to the respective antibiotics.