The design, synthesis and bioactivity evaluation of novel androgen receptor degraders based on hydrophobic tagging.

Prostate Cancer (PCa) easily progress to metastatic Castration-Resistant Prostate Cancer (mCRPC) that remains a significant cause of cancer-related death. Androgen receptor (AR)-dependent transcription is a major driver of prostate tumor cell proliferation. Proteolysis-targeting chimaera (PROTAC) technology based on Hydrophobic Tagging (HyT) represents an intriguing strategy to regulate the function of therapeutically androgen receptor proteins. In the present study, we have designed, synthesized, and evaluated a series of PROTAC-HyT AR degraders using AR antagonists, RU59063, which were connected with adamantane-based hydrophobic moieties by different alkyl chains. Compound D-4-6 exhibited significant AR protein degradation activity, with a degradation rate of 57 % at 5 µM and nearly 90 % at 20 µM in 24 h, and inhibited the proliferation of LNCaP cells significantly with an IC50 value of 4.77 ± 0.26 µM in a time-concentration-dependent manner. In conclusion, the present study lays the foundation for the development of a completely new class of therapeutic agents for the treatment of mCRPC, and further design and synthesis of AR-targeting degraders are currently in progress for better degradation rate.

Gliotoxin, a natural product with ferroptosis inducing properties.

As one of the mycotoxins produced by Aspergillus fumigatus, gliotoxin has a variety of pharmacological effects, such as anti-tumor, antibacterial, immunosuppressive. Antitumor drugs induce tumor cell death in several forms, including apoptosis, autophagy, necrosis and ferroptosis. Ferroptosis is a recently identified unique form of programmed cell death characterized by iron-dependent accumulation of lethal lipid peroxides, which induces cell death. A large amount of preclinical evidence suggests that ferroptosis inducers may enhance the sensitivity of chemotherapy and the induction of ferroptosis may be an effective therapeutic strategy to prevent acquired drug resistance. In our study, gliotoxin was characterized as a ferroptosis inducer and showed strong anti-tumor activity with IC50 of 0.24 µM and 0.45 µM in H1975 and MCF-7 cells at 72 h, respectively. Gliotoxin may provide a new natural template for the designing of ferroptosis inducers.

Annual review of KRAS inhibitors in 2022.

Kirsten rat sarcoma viral (KRAS) oncogene is the most commonly mutated isoform of RAS, accounting for 85% of RAS-driven human cancers. KRAS functioning as a signaling hub participates in multiple cellular signaling pathways and regulates a variety of critical processes such as cell proliferation, differentiation, growth, metabolism and migration. Over the past decades, KRAS oncoprotein has been considered as an "undruggable" target due to its smooth surface and high GTP/GDP affinity. The breakthrough in directly targeting G12C mutated-KRAS and recently approved covalent KRASG12C inhibitors sotorasib and adagrasib broke the myth of KRAS undruggable and confirmed the directly targeting KRAS as one of the most promising strategies for the treatment of cancers. Targeting KRASG12C successfully enriched the understanding of KRAS and brought opportunities for the development of inhibitors to directly target other KRAS mutations. With the stage now set for a new era in the treatment of KRAS-driven cancers, the development of KRAS inhibitors also enters a booming epoch. In this review, we overviewed the research progress of KRAS inhibitors with the potential to treat cancers covering articles published in 2022. The design strategies, discovery processes, structure-activity relationship (SAR) studies, cocrystal structure analysis as well as in vitro and in vivo activity were highlighted with the aim of providing updated sight to accelerate the further development of more potent inhibitors targeting various mutated-KRAS with favorable drug-like properties.

6-Heterocyclic carboxylic ester derivatives of gliotoxin lead to LSD1 inhibitors in gastric cancer cells.

Gliotoxin is a representative compound of the epipolythiodioxopiperazine (ETP) class of fungal metabolites. Histone Lysine Specific Demethylase 1 (LSD1) is highly expressed in a variety of cancers. Herein, a series of 6-heterocyclic carboxylic ester derivatives of gliotoxin was designed and synthesized as new LSD1 inhibitors and their biological evaluations in human gastric MGC-803 and HGC-27 cells were carried out. All of the derivatives effectively suppressed the enzymatic activities of LSD1. In particular, compound 4e exhibited excellent LSD1 inhibition with IC50 = 62.40 nM, as well as anti-proliferation against MGC-803 and HGC-27 cells with IC50 values of 0.31 µM and 0.29 µM, respectively. 4e also had a remarkable capacity to inhibit the colony formation, suppress migration and induce the apoptosis of these two cancer cell lines. In sum, our findings identified and characterized the 6-heterocyclic carboxylic ester derivatives of gliotoxin as potent and cellular active LSD1 inhibitors, which may provide a novel chemotype of LSD1 inhibitors for gastric cancer treatment.

Designed, synthesized and biological evaluation of proteolysis targeting chimeras (PROTACs) as AR degraders for prostate cancer treatment.

As a continuation of our research on developing potent and potentially safe androgen receptor (AR) degrader, a series of novel proteolysis targeting chimeras (PROTACs) containing the phthalimide degrons with different linker were designed, synthesized and evaluated for their AR degradation activity against LNCaP (AR+) cell line. Most of the synthesized compounds displayed moderate to satisfactory AR binding affinity and might lead to antagonist activity against AR. Among them, compound A16 exhibited the best AR binding affinity (85%) and degradation activity against AR. Due to the strong fluorescence properties of pomalidomide derivatives, B10 was found to be effectively internalized and visualized in LNCaP (AR + ) cells than PC-3 (AR-) cells. Moreover, the molecular docking of A16 with AR and the active site of DDB1-CRBN E3 ubiquitin ligase complex provides guidance to design new PROTAC degrons targeting AR for prostate cancer therapy. These results represent a step toward the development of novel and improved AR PROTACs.

Synthesis and biological evaluation of 17-cyanopyridine derivatives of pregnenolone as potential anti-prostate cancer agents.

A series of new 17-cyanopyridine derivatives of pregnenolone have been synthesized, and their anti-proliferative activities against different human cancer cell lines were tested. The extensive structure-activity relationship (SAR) data suggested that the introduction of 2-amino-4-aryl-3-cyanopyridine to the D ring of pregnenolone may increase the anti-cancer activity. Among the products, the most potent compound 4j exhibited good growth inhibition against all the tested cells especially for PC- 3 cells with an IC50 value of 2.0 µM. Further mechanistic studies showed that 4j inhibited the formation of cell colonies and migration, increased the level of reactive oxygen species (ROS) in PC-3 cells in a concentration-dependent manner, and induced necroptosis through the phosphorylation of receptor interacting protein 1/3 (P-RIP1/3) and phosphorylation of mixed lineage kinase domain-like protein (P-MLKL) pathway. The 17-pregnenolone cyanopyridine derivatives hold promising potential as anti-proliferative agents, and the most potent compound could be used as a starting point for the development of new steroidal heterocycles with improved anticancer potency and selectivity.

Biotransformation of androst-4-ene-3,17-dione by three fungal species Fusarium solani BH1031, Aspergillus awamori MH18 and Mucor circinelloides W12.

The microbial transformation of androst-4-ene-3,17-dione (4-AD; I) by three fungal species, involved Fusarium solani BH1031, Aspergillus awamori MH18 and Mucor circinelloides W12, has been studied. The latter two fungi were studied for the first time on biotransformation of 4-AD. The main product obtained by Fusarium solani BH1031 was 17α-oxa-D-homo-androst-1,4-diene-3,17-dione (testolactone; IV), which can be used as an anticancer agent. The main derivative yielded by Aspergillus awamori MH18 was 11α-hydroxyandrost-4-ene-3,17-dione (11α-OH-4-AD; VI), which was an important intermediate to produce Eplerenone. Meanwhile, the microbial transformation of 4-AD by Mucor circinelloides W12 produced three derivatives. Possible metabolic pathway of 4-AD via Fusarium solani BH1031 was proposed. Furthermore, the optimization for the production of 11α-OH-4-AD was carried out and the conversion rate reached to 84.0%. In this process, the dextrin and corn flour showed significant effects by response surface analysis.

Screening and pharmacodynamic evaluation of the antirespiratory syncytial virus activity of steroidal pyridine compounds in vitro and in vivo.

Respiratory syncytial virus (RSV) causes serious lower respiratory tract infections and there are currently no safer or more effective drugs available. It is important to find novel medications for RSV infection. A series of steroidal pyridines were synthesized for screening and evaluation of their antiviral activity and investigation of their antiviral mechanism of action. Compound 3l had the highest antiviral activity, with a half-maximal effective concentration (EC50 ) of 3.13 µM. Compound 3l was explored for its effects in vitro on RSV 2 h before infection (pretreatment), at the time of infection (competition), and 2 h after infection (postinfection). Toll-like receptor (TLR)-3, retinoic acid-inducible gene (RIG)-I, interleukin (IL)-6, and interferon (IFN)-ß were suppressed at the cellular level. Mouse lung tissue was subjected to hematoxylin and eosin (HE) staining and immunohistochemistry, which showed that RSV antigen and M gene expression could be reduced by compound 3l. Decreased expression of TLR-3, RIG-I, IL-6, IFN-ß, and IL-10 was also found in vivo. The results indicated that compound 3l exerted its antiviral effects mainly through inhibition of viral replication and downregulation of inflammatory factors.

New Non-Nucleocide NS5B Protein Inhibitors for the Treatment of Chronic Hepatitis C Infection.

Hepatitis C virus is one of the major causative pathogens of chronic hepatitis and the second most common cause of hepatocellular cancer. The virally encoded NS5B RNA-dependent RNA polymerase is a vital component of the replicase complex that orchestrates the replication process leading to the production of progeny virus. In recent years, developing novel drugs to target NS5B polymerase has become one of the important strategies for the treatment of chronic hepatitis C infection. This review highlights the structure and scaffold of the non-nucleoside NS5B inhibitors represented in the past five years.

Enhanced expression of cohesin loading factor NIPBL confers poor prognosis and chemotherapy resistance in non-small cell lung cancer.

BACKGROUND: NIPBL, the sister chromatid cohesion 2 (SCC2) human homolog, is a cohesin loading factor which is essential for deposition of cohesin onto the sister chromatid. Recent studies have shown that NIPBL contribute to sister chromatid cohesion and plays a critical role in development, DNA repair, and gene regulation. In this study, we measured the expression of NIPBL in clinical non-small cell lung cancer specimens, and determined its effects on cellular processes and chemosensitivity in vitro. METHODS: NIPBL immunohistochemistry was performed on 123 lung adenocarcinoma samples. Through knockdown of NIPBL protein expression, non-small cell lung cancer cell lines were used to test the potential involvement of NIPBL silencing on cell proliferation, migration, invasion, and apoptosis. Chemosensitivity was assessed with clonogenic assays, and chromatin immunoprecipitation assays were performed to analyze the relationship between NIPBL and signal transducers and activators of transcription 3 (STAT3). RESULTS: Immunohistochemical analysis showed that high expression of NIPBL was strongly correlated with poor prognosis, tumor differentiation, and lymph node metastasis. Survival analysis further indicated that NIPBL expression was a potential prognostic factor for non-small cell lung cancer. Knockdown of NIPBL in non-small cell lung cancer cell lines significantly reduced cellular proliferation, migration, and invasion, and enhanced cellular apoptosis and sensitivity to cisplatin, paclitaxel, and gemcitabine hydrochloride. NIPBL bound to the promoter region of the STAT3 gene, directly regulating the expression of STAT3. CONCLUSIONS: These data suggested that NIPBL played a significant role in lung carcinogenesis. NIPBL expression conferred poor prognosis and resistance to chemotherapy in non-small cell lung cancer, suggesting that NIPBL may be a novel therapeutic target.

Discovery of novel steroidal pyran-oxindole hybrids as cytotoxic agents.

A series of novel steroidal pyran-oxindole hybrids were efficiently synthesized in a single operation through the vinylogous aldol reaction of vinyl malononitrile 3 with substituted isatins involving the construction of C-C and C-O bonds. Some compounds displayed moderate to good cytotoxicity against T24, SMMC-7721, MCF-7 and MGC-803 cells. Compounds 4f and 4i were more potent than 5-Fu against T24 and MGC-803 cells with the IC50 values of 4.43 and 8.45 µM, respectively. Further mechanism studies indicated that compound 4i induced G2/M arrest and early apoptosis in a concentration- and time-dependent manner.

Synthesis of 3beta, 7alpha, 11alpha-trihydroxy-pregn-21-benzylidene-5-en-20-one derivatives and their cytotoxic activities.

A series of novel 3beta, 7alpha, 11alpha-trihydroxy-pregn-21-benzylidene-5-en-20-one derivatives were synthesized and characterized by NMR, HRMS. The pregnenolone (1) was first biotransformed by Mucor circinelloides var lusitanicus to 3beta, 7alpha, 11alpha-trihydroxy-pregn-5-en-20-one (3), then 3 was treated with various benzaldehydes to produce 3beta, 7alpha, 11alpha-trihydroxy-pregn-21-benzylidene-5-en-20-one derivatives. These derivatives showed remarkable activity against EC109 cells. The absolute configuration of 3 was also confirmed by signal-crystal X-ray analysis.