Design, synthesis and biological evaluation of Thiazolo[3, 2-a]Pyrimidine derivatives as novel RNase H inhibitors.

Targeting Ribonuclease H (RNase H) has been considered a viable strategy for HIV therapy. In this study, a series of novel thiazolo[3, 2-a]pyrimidine derivatives were firstly designed and synthesized as potential inhibitors of HIV-1 RNase H. Among these compounds, A28 exhibited the most potent inhibition against HIV-1 RNase H with an IC50 value of 4.14 µM, which was about 5-fold increase in potency than the hit compound A1 (IC50 = 21.49 µM). To gain deeper insights into the structure-activity relationship (SAR), a CoMFA model was constructed to yield reasonable statistical results (q2 = 0.658 and R2 = 0.969). Results from magnesium ion chelation experiments and molecular docking studies revealed that these thiazolopyrimidine inhibitors may exert their inhibitory activity by binding to an allosteric site on RNase H at the interface between subunits p51 and p66. Furthermore, this analog demonstrated favorable physicochemical properties. Our findings provide valuable groundwork for further development of allosteric inhibitors targeting HIV-1 RNase H.

Structure-guided design of novel biphenyl-quinazoline derivatives as potent non-nucleoside reverse transcriptase inhibitors featuring improved anti-resistance, selectivity, and solubility.

In pursuit of enhancing the anti-resistance efficacy and solubility of our previously identified NNRTI 1, a series of biphenyl-quinazoline derivatives were synthesized employing a structure-based drug design strategy. Noteworthy advancements in anti-resistance efficacy were discerned among some of these analogs, prominently exemplified by compound 7ag, which exhibited a remarkable 1.37 to 602.41-fold increase in potency against mutant strains (Y181C, L100I, Y188L, F227L + V106A, and K103N + Y181C) in comparison to compound 1. Compound 7ag also demonstrated comparable anti-HIV activity against both WT HIV and K103N, albeit with a marginal reduction in activity against E138K. Of significance, this analog showed augmented selectivity index (SI > 5368) relative to compound 1 (SI > 37764), Nevirapine (SI > 158), Efavirenz (SI > 269), and Etravirine (SI > 1519). Moreover, it displayed a significant enhancement in water solubility, surpassing that of compound 1, Etravirine, and Rilpivirine. To elucidate the underlying molecular mechanisms, molecular docking studies were undertaken to probe the critical interactions between 7ag and both WT and mutant strains of HIV-1 RT. These findings furnish invaluable insights driving further advancements in the development of DAPYs for HIV therapy.

Roles of HDAC2, eIF5, and eIF6 in Lung Cancer Tumorigenesis.

OBJECTIVE: The expression levels of histone deacetylase 2 (HDAC2), eukaryotic initiation factor 5 (eIF5), and eukaryotic initiation factor 6 (eIF6), and relationship between HDAC2 and eIF5 or eIF6 in lung cancer tissues were investigated, in order to charify the relationship between HDAC2 and the prognosis of lung cancer patients and its influence on the expression of eIF5 and eIF6. METHODS: The expression of HDAC2, eIF5, and eIF6 in lung cancer tissues was detected by quantitative reverse transcription polymerase chain reaction. The expression correlation between HDAC2 and eIF5 or eIF6 was tested using a t test. The correlation between HDAC2 and eIF5 or eIF6 was analyzed using the TCGA database. The identified cells were constructed with small interfering siRNA and HDAC2 overexpression plasmid. The proliferation and migration ability of the identified cells was investigated by CCK8 and Transwell assays, respectively. RESULTS: HDAC2, eIF5, and eIF6 were overexpressed in lung cancer tissues, and HDAC2 expression level was negatively correlated with the prognosis of lung cancer patients. HDAC2 expression level was positively correlated with eIF5 and eIF6 expression levels. HDAC2 could regulate the expression of eIF5 and eIF6. The regulation of proliferation and invasion of lung cancer cells by HDAC2 depended on eIF5 and eIF6. CONCLUSION: HDAC2, eIF5, and eIF6 were closely related with lung cancer tumorigenesis, which might be potential biological markers and therapeutic targets for lung cancer.

Overexpression of c-Ski promotes cell proliferation, invasion and migration of gastric cancer associated fibroblasts.

The present study aimed to investigate the effects of c-Ski on cell proliferation, invasion and migration of gastric cancer associated fibroblasts (CAFs). Expression of c-Ski in gastric cancer (GC) tissues was determined using immunohistochemistry. Both CAFs and non-cancerous gastric fibroblasts (NGFs) were isolated and cultured. c-Ski and Smad3 were over-expressed or knocked down using pcDNA3.0-c-Ski/Smad3 or siRNA, respectively. Cell viability, invasion and migration were measured and expression of c-Ski, α-SMA, and Smad3 in cells was determined using real time quantitative PCR (RT-qPCR) and Western blotting. Expression of c-Ski was significantly higher in both in GC tissues and cell lines, and was the highest in tissues of diffuse type. Both c-Ski and α-SMA were significantly over-expressed in CAFs compared with that in the NGFs. When c-Ski was over-expressed in NGFs, cell viability, cell invasion and migration were all enhanced and expression of Smad3 was downregulated. When c-Ski was inhibited, cell viability, cell invasion, and migration were all suppressed and expression of Smad3 was upregulated. Meanwhile, overexpression of Smad3 significantly reversed the effects of over-expressed c-Ski in NGFs, and knockdown of Smad3 dramatically reversed the effects of si-c-Ski in CAFs. Over-expressed c-Ski could enhance cell viability, promote cell invasion, and migration of GC CAFs, and the effects might be through regulation of Smad3 signaling. This study may give deeper insights for relationship between c-Ski and CAFs, as well as role of c-Ski in cancer development, and also provide some novel research targets for treatment of GC.