Objective To design and synthesize PROTAC degraders targeting the SARS-CoV-2 main protease （M^pro）based on PROTAC technology. Methods Compound 3w was used as the M^pro ligand, and the indole N atom in the solvent-exposed region was selected as the linker attachment site. A series of M^pro PROTACs were designed and synthesized by conjugating compound 3w with the CRBN ligand pomalidomide through alkane linkers of different lengths. The structures of the target compounds were confirmed by ¹H NMR, ¹³C NMR, and HRMS. Western Blot analysis was employed to evaluate their degradation activity and explore its mechanism in M^pro-HEK-293T cells. Results Four novel M^pro PROTACs（A1-A4）were successfully synthesized. The most potent compound A4 demonstrated M^pro degradation activity with a DC₅₀ value of 5.2 μmol/L, and its degradation mechanism was validated. Conclusion A novel class of M^pro PROTAC degraders were successfully designed and synthesized, and their protein degradation capability and mechanism of action were demonstrated. These results provided lead compounds for the research and development of antiviral degraders against SARS-CoV-2.

Objective To screen small molecule inhibitors of Fusobacterium nucleatum （Fn） based on commercially available compound libraries, and investigate their anti-colorectal cancer activities under Fn intervention in order to obtain novel anti-colorectal cancer lead compounds. Methods The promotion of colorectal cancer proliferation on organoid was validated by Fn. Secondly, the effects of anti-Fn compounds on their in vitro anticancer activity under Fn’s co-incubation with colorectal cancer HCT116 cell were comparative investigated. Finally, in vivo anticancer efficacy of highly active compounds on nude mouse colon cancer HCT116 transplanted tumor under the intervention of Fn was evaluated by gavage. Results Fn could significantly promote the proliferation of rectal cancer organoids. 9 anti-Fn active compounds could significantly enhance their in vitro anticancer activity under Fn’s co-incubation with HCT116 cells. Methotrexate had the strongest anti-cancer activity with IC₅₀ as 0.03 μmol/L. The combined use of methotrexate (0.5 mg/kg) and PD-1 (5.0 mg/kg) had a stronger anti-tumor effect than their standalone use. Conclusion As new small molecule inhibitor of Fn, methotrexate exhibited good in vitro and in vivo anti-colorectal cancer activity against HCT116 cells and nude mouse xenografts under Fn intervention, which showed the foundation for subsequent structural optimization, and could be expected to expand the new indications of methotrexate.

Ferroptosis,discovered in 2012,is a newly form of non-apoptotic and non-necrotic cell death,which is characterized by an increasement in lipid peroxidation and accumulation of intracellular iron ions.Glutathione peroxidase 4(GPX4)is the fourth member of the selenoprotein GPx family and plays a crucial role in clearing lipid peroxides in cells,making it an important regulator of ferroptosis.Small molecule inhibitors targeting GPX4 can induce ferroptosis,offering a new strategy for treating drug-resistant cancers and neurodegenerative diseases.The protein structure and function of GPX4 were primarily discusseed,and the latest advances in small molecule inhibitors of GPX4 were summarized,which provided a research foundation for developing ferroptosis inducers based on GPX4 inhibition.

Objective To design and synthesize autophagic degraders targeting BRD4 based on autophagosome tethering compound (ATTEC) strategy and test their BRD4 degradation activity. Methods BRD4-targeting ATTECs were constructed by conjugating ispinesib that used as a LC3 ligand and JQ1 through a variety of alkane linkers. The final compounds were confirmed by ¹H NMR, ¹³C NMR and ESI-MS, and their degradation activity in different cell lines were tested by Western Blot. Results Five BRD4-ATTEC molecules were successfully synthesized for the first time. Compound 4 showed moderate BRD4 degradation activity in different cell lines. Conclusion The novel BRD4 autophagic degraders were discovered, which expanded the applicability of targeted autophagic degradation via ATTEC.

Targeted protein degradation (TPD) techniques eliminate pathogenic proteins by hijacking the intracellular proteolysis machinery which includes the ubiquitin-proteasome system (UPS) and the lysosomal degradation pathway, holding promise to overcome the limitations of traditional inhibitors and further broaden the target space including many “undruggable” targets, and provide new targeted treatments for drug discovery. In this review, recent advances in a variety of promising TPD strategies were summarized, such as proteolysis targeting chimera (PROTAC), molecular glue, lysosome-targeting chimaera (LYTAC), autophagosome-tethering compound (ATTEC), autophagy-targeting chimera AUTAC and AUTOTAC, particularly. The representative case studies, potential applications and challenges were analyzed.

Invasive fungal infections (IFIs) have been associated with high mortality, highlighting the urgent need for developing novel antifungal strategies. Herein the first light-responsive antifungal agents were designed by optical control of fungal ergosterol biosynthesis pathway with photocaged triazole lanosterol 14α-demethylase (CYP51) inhibitors. The photocaged triazoles completely shielded the CYP51 inhibition. The content of ergosterol in fungi before photoactivation and after photoactivation was 4.4% and 83.7%, respectively. Importantly, the shielded antifungal activity (MIC₈₀ ≥ 64 μg/mL) could be efficiently recovered (MIC₈₀ = 0.5-8 μg/mL) by light irradiation. The new chemical tools enable optical control of fungal growth arrest, morphological conversion and biofilm formation. The ability for high-precision antifungal treatment was validated by in vivo models. The light-activated compound A1 was comparable to fluconazole in prolonging survival in Galleria mellonella larvae with a median survival of 14 days and reducing fungal burden in the mouse skin infection model. Overall, this study paves the way for precise regulation of antifungal therapy with improved efficacy and safety.

KRAS‒PDEδ interaction is revealed as a promising target for suppressing the function of mutant KRAS. The bottleneck in clinical development of PDEδ inhibitors is the poor antitumor activity of known chemotypes. Here, we identified novel spiro-cyclic PDEδ inhibitors with potent antitumor activity both in vitro and in vivo. In particular, compound 36l (K _D = 127 ± 16 nmol/L) effectively bound to PDEδ and interfered with KRAS-PDEδ interaction. It influenced the distribution of KRAS in Mia PaCa-2 cells, downregulated the phosphorylation of t-ERK and t-AKT and promoted apoptosis of the cells. The novel inhibitor 36l exhibited significant in vivo antitumor potency in pancreatic cancer patient-derived xenograft (PDX) models. It represents a promising lead compound for investigating the druggability of KRAS‒PDEδ interaction.

Objective To evaluate the in vitro synergistic antifungal activity of HDAC inhibitors in combination with azole drugs against azoles-resistant Candida strains. Methods The checkerboard microdilution method was used to evaluate the antifungal activity of the HDAC inhibitors in combination with azole drugs against clinically drug-resistant strains. The fungistatic activity and toxicity of Rocilinostat was determined through time-growth curve assay and cytotoxicity assay. Results The compound Rocilinostat combined with azole drugs showed excellent synergistic antifungal activity against a variety of azoles-resistant Candida albicans and Candida glabrata. The combination of high concentration Rocilinostat with FLC exhibited fungistatic effects. Very low toxicity was detected with Rocilinostat towards normal cells. Rocilinostat showed better HDAC inhibitory activity than SAHA. Conclusion As a fungi HDAC inhibitor, Rocilinostat has excellent in vitro synergistic antifungal activity and no severe toxicity to normal human cells.

Nicotinamide phosphoribosyl transferase (NAMPT) is considered as a promising target for cancer therapy given its critical engagement in cancer metabolism and inflammation. However, therapeutic benefit of NAMPT enzymatic inhibitors appears very limited, likely due to the failure to intervene non-enzymatic functions of NAMPT. Herein, we show that NAMPT dampens antitumor immunity by promoting the expansion of tumor infiltrating myeloid derived suppressive cells (MDSCs) via a mechanism independent of its enzymatic activity. Using proteolysis-targeting chimera (PROTAC) technology, PROTAC A7 is identified as a potent and selective degrader of NAMPT, which degrades intracellular NAMPT (iNAMPT) via the ubiquitin-proteasome system, and in turn decreases the secretion of extracellular NAMPT (eNAMPT), the major player of the non-enzymatic activity of NAMPT. In vivo, PROTAC A7 efficiently degrades NAMPT, inhibits tumor infiltrating MDSCs, and boosts antitumor efficacy. Of note, the anticancer activity of PROTAC A7 is superior to NAMPT enzymatic inhibitors that fail to achieve the same impact on MDSCs. Together, our findings uncover the new role of enzymatically-independent function of NAMPT in remodeling the immunosuppressive tumor microenvironment, and reports the first NAMPT PROTAC A7 that is able to block the pro-tumor function of both iNAMPT and eNAMPT, pointing out a new direction for the development of NAMPT-targeted therapies.

Metabolic-associated fatty liver disease (MAFLD), which is previously known as non-alcoholic fatty liver disease (NAFLD), represents a major health concern worldwide with limited therapy. Here, we provide evidence that ferroptosis, a novel form of regulated cell death characterized by iron-driven lipid peroxidation, was comprehensively activated in liver tissues from MAFLD patients. The canonical-GPX4 (cGPX4), which is the most important negative controller of ferroptosis, is downregulated at protein but not mRNA level. Interestingly, a non-canonical GPX4 transcript-variant is induced (inducible-GPX4, iGPX4) in MAFLD condition. The high fat-fructose/sucrose diet (HFFD) and methionine/choline-deficient diet (MCD)-induced MAFLD pathologies, including hepatocellular ballooning, steatohepatitis and fibrosis, were attenuated and aggravated, respectively, in cGPX4-and iGPX4-knockin mice. cGPX4 and iGPX4 isoforms also displayed opposing effects on oxidative stress and ferroptosis in hepatocytes. Knockdown of iGPX4 by siRNA alleviated lipid stress, ferroptosis and cell injury. Mechanistically, the triggered iGPX4 interacts with cGPX4 to facilitate the transformation of cGPX4 from enzymatic-active monomer to enzymatic-inactive oligomers upon lipid stress, and thus promotes ferroptosis. Co-immunoprecipitation and nano LC-MS/MS analyses confirmed the interaction between iGPX4 and cGPX4. Our results reveal a detrimental role of non-canonical GPX4 isoform in ferroptosis, and indicate selectively targeting iGPX4 may be a promising therapeutic strategy for MAFLD.