Publications

The HIV capsid (CA) protein is a promising target for anti-AIDS treatment due to its critical involvement in viral replication. Herein, we utilized the well-documented CA inhibitor PF74 as our lead compound and designed a series of low-molecular-weight phenylalanine derivatives. Among them, compound 7t exhibited remarkable antiviral activity with a high selection index (EC₅₀ = 0.040 µM, SI = 2815), surpassing that of PF74 (EC₅₀ = 0.50 µM, SI = 258). Furthermore, when evaluated against the HIV-2 strain, 7t (EC₅₀ = 0.13 µM) demonstrated approximately 14-fold higher potency than that of PF74 (EC₅₀ = 1.76 µM). Insights obtained from surface plasmon resonance (SPR) revealed that 7t exhibited stronger target affinity to the CA hexamer and monomer in comparison to PF74. The potential interactions between 7t and the HIV-1 CA were further elucidated using molecular docking and molecular dynamics simulations, providing a plausible explanation for the enhanced target affinity with 7t over PF74. Moreover, the metabolic stability assay demonstrated that 7t (T_1/2 = 77.0 min) significantly outperforms PF74 (T_1/2 = 0.7 min) in human liver microsome, exhibiting an improvement factor of 110-fold. In conclusion, 7t emerges as a promising drug candidate warranting further investigation.

In this study, privileged boronic acid ester was introduced into the right wing of etravirine (ETR) to obtain a series of novel boronate-containing derivatives. These newly synthesized derivatives were evaluated for their anti-HIV potency in MT-4 cells using the MTT method, and their inhibitory activity to HIV-1 reverse transcriptase (RT) was assayed by the ELISA method. Most of the synthesized compounds displayed promising antiviral activity against the wild-type and a wide range of HIV-1 mutant strains. In particular, <b>4a</b> exhibited the most potent activity against the wild-type and a panel of single mutations (L100I, K103N, Y181C, and E138K) with EC₅₀ values ranging from 0.005 to 0.648 μM, which were much superior to those of nevirapine (EC₅₀ = 0.151 μM). Moreover, <b>4b</b> turned out to be an effective inhibitor against the double-mutant strains F227L + V106A and RES056 with EC₅₀ values of 3.21 and 2.30 μM, respectively. RT inhibition activity and molecular docking were also investigated.

A series of novel diarylpyrimidines (DAPYs) with a ketone hydrazone substituent on the methylene linker between the pyrimidine nucleus and the aryl moiety at the C-4 position were synthesized, and their antiviral activity against human immunodeficiency virus (HIV)-1 in MT-4 cells was evaluated. Most compounds of this class exhibited excellent activity against wild-type HIV-1, with EC(50) values in the range of 1.7-13.2 nM. Of these compounds, 2-bromophenyl-2-[(4-cyanophenyl)amino]-4-pyrimidinone hydrazone (9k) displayed the most potent anti-HIV-1 activity (EC(50) =1.7±0.6 nM), with excellent selectivity for infected over uninfected cells (SI=5762). In addition, the 4-methyl phenyl analogue 9d (EC(50) =2.4±0.2 nM, SI=18461) showed broad spectrum HIV inhibitory activity, with EC(50) values of 2.4±0.2 nM against wild-type HIV-1, 5.3±0.4 μM against HIV-1 double-mutated strain RES056 (K103N+Y181C), and 5.5 μM against HIV-2 ROD strain. Furthermore, structure-activity relationship (SAR) data and molecular modeling results for these compounds are also discussed.

Based on the detailed analysis of the binding mode of diarylpyrimidines (DAPYs) with HIV-1 RT, we designed several subseries of novel NNRTIs, with the aim to probe biologically relevant chemical space of solvent-exposed tolerant regions in NNRTIs binding pocket (NNIBP). The most potent compound <b>21a</b> exhibited significant activity against the whole viral panel, being about 1.5-2.6-fold (WT, EC₅₀ = 2.44 nM; L100I, EC₅₀ = 4.24 nM; Y181C, EC₅₀ = 4.80 nM; F227L + V106A, EC₅₀ = 17.8 nM) and 4-5-fold (K103N, EC₅₀ = 1.03 nM; Y188L, EC₅₀ = 7.16 nM; E138K, EC₅₀ = 3.95 nM) more potent than the reference drug ETV. Furthermore, molecular simulation was conducted to understand the binding mode of interactions of these novel NNRTIs and to provide insights for the next optimization studies.

The chemokine receptor CXCR3 can exhibit weak coreceptor function for several human immunodeficiency virus type 1 (HIV-1) and HIV-2 strains and clinical isolates. These viruses produced microscopically visible cytopathicity in U87.CD4.CXCR3 cell cultures, whereas untransfected (CXCR3-negative) U87.CD4 cells remained uninfected. Depending on the particular virus, the coreceptor efficiency of CXCR3 was 100- to >10,000-fold lower compared to that of CXCR4. A CXCR3 variant carrying the CXCR4 binding pocket was constructed by simultaneous lysine-to-alanine and serine-to-glutamate substitutions at positions 300 and 304 of the CXCR3 receptor. This mutant receptor (CXCR3[K300A, S304E]) showed markedly enhanced HIV coreceptor function compared to the wild-type receptor (CXCR3[WT]). Moreover, the CXCR4 antagonist AMD3100 exhibited antagonistic and anti-HIV activities in U87.CD4.CXCR3[K300A, S304E] cells but not in U87.CD4.CXCR3[WT] cells.

A comparative study of three cycloSal-d4TMP 1, 2 and 3 and a variety of bis(benzyl) phosphate triester 4-8 of the antivirally active nucleoside analogue 2',3'-dideoxy-2',3'-didehydrothymidine (d4T) will be described. This study has been initiated by the observation that the introduction of a simple 7-methyl group in the cycloSal-structure (2) led to a completely different hydrolysis pattern as compared to the prototype cycloSal-d4TMP 1. Instead of the selective formation of d4TMP, a phenyl phosphate diester was formed in the case of the 7-methyl-substituted compound 2. The difference in degradation pathway was caused by a change of the reaction mechanism. The phenyl phosphate diester was chemically and enzymatically inert to further cleavage to yield d4TMP. For comparison bis(benzyl)-d4TMP 4, bis(alpha-methylbenzyl)-d4TMP 5, bis(alpha-methoxycarbonylmethyl [MCM]-benzyl)-d4TMP 6 as well as the enzyme-cleavable bis(4-acetoxybenzyl)-d4TMP [bis(AB)-d4TMP(7 and bis(alpha-methoxycarbonylmethyl-4-acetoxybenzyl)-d4TMP [bis(alpha-MCM-AB)-d4TMP] 8 were synthesized. Chemical hydrolysis studies proved that all bis(benzyl) triesters hydrolyze to give the intermediate benzyl phosphate diesters. Moreover, the latter two triesters 7,8 and cycloSal-d4TMPs 1 and 3 led finally to the delivery of d4TMP. The chemical hydrolysis studies allowed a detailed mechanistic interpretation of the degradation pathways of triesters 1-8. Cell extract studies of the bis(benzyl) triesters 4-8 confirmed that only triesters 7 and 8 released d4TMP although with a considerable increase of the reaction rate. Anti-HIV evaluation of the compounds showed that cycloSal-d4TMP 1 and the bis(AB) triesters 7,8 were entirely independent of the presence of cellular thymidine kinase (TK).