TTK inhibition activates STING signal and promotes anti-PD1 immunotherapy in breast cancer.

Despite progress in the application of checkpoint immunotherapy against various tumors, attempts to utilize immune checkpoint blockade (ICB) agents in triple negative breast cancer (TNBC) have yielded limited clinical benefits. The low overall response rate of checkpoint immunotherapy in TNBC may be attributed to the immunosuppressive tumor microenvironment (TME). In this study, we investigated the role of mitogen-associated kinase TTK in reprogramming immune microenvironment in TNBC. Notably, TTK inhibition by BAY-1217389 induced DNA damage and the formation of micronuclei containing dsDNA in the cytosol, resulting in elicition of STING signal pathway and promoted antitumor immunity via the infiltration and activation of CD8+ T cells. Moreover, TTK inhibition also upregulated the expression of PD-L1, demonstrating a synergistic effect with anti-PD1 therapy in 4T1 tumor-bearing mice. Taken together, TTK inhibition facilitated anti-tumor immunity mediated by T cells and enhanced sensitivity to PD-1 blockade, providing a rationale for the combining TTK inhibitors with immune checkpoint blockade in clinical trials.

Discovery of a first-in-class degrader for the protein arginine methyltransferase 6 (PRMT6).

PRMT6 is a member of the protein arginine methyltransferase family, which participates in a variety of physical processes and plays an important role in the occurrence and development of tumors. Using small molecules to design and synthesize targeted protein degraders is a new strategy for drug development. Here, we report the first-in-class degrader SKLB-0124 for PRMT6 based on the hydrophobic tagging (HyT) method.Importantly, SKLB-0124 induced proteasome dependent degradation of PRMT6 and significantly inhibited the proliferation of HCC827 and MDA-MB-435 cells. Moreover, SKLB-0124 effectively induced apoptosis and cell cycle arrest in these two cell lines. Our data clarified that SKLB-0124 is a promising selective PRMT6 degrader for cancer therapy which is worthy of further evaluation.

Single-cell RNA sequencing reveals diverse B cell phenotypes in patients with anti-NMDAR encephalitis.

BACKGROUNDS: Anti-N-methyl-D-aspartate receptor encephalitis (NMDAR-E) is a severe autoimmune disorder characterized by prominent psychiatric symptoms. Although the role of NMDAR antibodies in the disease has been extensively studied, the phenotype of B cell subsets is still not fully understood. METHODS: We utilized single-cell RNA sequencing, single-cell B cell receptor sequencing (scBCR-seq), bulk BCR sequencing, flow cytometry, and enzyme-linked immunosorbent assay to analyze samples from both NMDAR-E patients and control individuals. RESULTS: The cerebrospinal fluid (CSF) of NMDAR-E patients showed significantly increased B cell counts, predominantly memory B (Bm) cells. CSF Bm cells in NMDAR-E patients exhibited upregulated expression of differential expression genes (DEGs) associated with immune regulatory function (TNFRSF13B and ITGB1), whereas peripheral B cells upregulated DEGs related to antigen presentation. Additionally, NMDAR-E patients displayed higher levels of IgD- CD27- double negative (DN) cells and DN3 cells in peripheral blood (PB). In vitro, DN1 cell subsets from NMDAR-E patients differentiated into DN2 and DN3 cells, while CD27+ and/or IgD+ B cells (non-DN) differentiated into antibody-secreting cells (ASCs) and DN cells. NR1-IgG antibodies were found in B cell culture supernatants from patients. Differential expression of B cell IGHV genes in CSF and PB of NMDAR-E patients suggests potential antigen class switching. CONCLUSION: B cell subpopulations in the CSF and PB of NMDAR-E patients exhibit distinct compositions and transcriptomic features. In vitro, non-DN cells from NMDAR-E can differentiate into DN cells and ASCs, potentially producing NR1-IgG antibodies. Further research is necessary to investigate the potential contribution of DN cell subpopulations to NR1-IgG antibody production.

Is repeat sentinel lymph node biopsy possible for surgical axillary staging among patients with ipsilateral breast tumor recurrence?

BACKGROUND: There is a lack of studies assessing the survival of repeat sentinel lymph node biopsy (rSLNB) versus axillary lymph node dissection (ALND) for surgical axillary staging among patients with ipsilateral breast tumor recurrence (IBTR). METHODS: We retrospectively identified patients with IBTR from the Surveillance, Epidemiology, and End Results database from 2000 to 2017. The primary outcome was overall survival (OS) between the rSLNB and ALND groups. RESULTS: Of the 2141 women with IBTR after lumpectomy and SLNB, 524 did not receive surgical axillary staging (nonsurgery group) and 1617 patients who did undergo axilla surgery received either rSLNB or ALND as axillary staging (1268 with rSLNB and 349 with ALND). The 10-year OS rates were 61.9% for the nonsurgery and 73.8% for axilla surgery groups (p = .001). In the 1:1 matched cohorts, the 10-year OS rates were 61.4% for the nonsurgery and 69.1% for axilla surgery groups (p = .072). After adjusting for other factors, axillary surgery treatment of IBTR was an independent favorable factor for OS (hazard ratio [HR], 0.71; 95% CI, 0.56-0.90; p = .004). Within the axilla surgery group, rSLNB presented a comparable 10-year OS to the ALND cohort (log-rank test p = .054). Multivariate Cox analysis, as well as subgroup analysis, showed that rSLNB had a similar benefit to ALND (10-year OS; HR, 1.18; 95% CI, 0.88-1.58; p = .268). CONCLUSIONS: The results of this cohort study suggested that receiving surgical axillary staging was associated with better survival of IBTR patients, and rSLNB had a similar long-term survival outcome as ALND. rSLNB might be considered for surgical axillary staging among patients with IBTR after lumpectomy and initial SLNB.

Nifuroxazide ameliorates pulmonary fibrosis by blocking myofibroblast genesis: a drug repurposing study.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a serious interstitial lung disease with a complex pathogenesis and high mortality. The development of new drugs is time-consuming and laborious; therefore, research on the new use of old drugs can save time and clinical costs and even avoid serious side effects. Nifuroxazide (NIF) was originally used to treat diarrhoea, but more recently, it has been found to have additional pharmacological effects, such as anti-tumour effects and inhibition of inflammatory diseases related to diabetic nephropathy. However, there are no reports regarding its role in pulmonary fibrosis. METHODS: The therapeutic effect of NIF on pulmonary fibrosis in vivo was measured by ELISA, hydroxyproline content, H&E and Masson staining, immunohistochemistry (IHC) and western blot. Immune cell content in lung tissue was also analysed by flow cytometry. NIF cytotoxicity was evaluated in NIH/3T3 cells, human pulmonary fibroblasts (HPFs), A549 cells and rat primary lung fibroblasts (RPLFs) using the MTT assay. Finally, an in vitro cell model created by transforming growth factor-ß1 (TGF-ß1) stimulation was assessed using different experiments (immunofluorescence, western blot and wound migration assay) to evaluate the effects of NIF on the activation of NIH/3T3 and HPF cells and the epithelial-mesenchymal transition (EMT) and migration of A549 cells. RESULTS: In vivo, intraperitoneal injection of NIF relieved and reversed pulmonary fibrosis caused by bleomycin (BLM) bronchial instillation. In addition, NIF inhibited the expression of a variety of cellular inflammatory factors and immune cells. Furthermore, NIF suppressed the activation of fibroblasts and EMT of epithelial cells induced by TGF-ß1. Most importantly, we used an analytical docking experiment and thermal shift assay to further verify that NIF functions in conjunction with signal transducer and activator of transcription 3 (Stat3). Moreover, NIF inhibited the TGF-ß/Smad pathway in vitro and decreased the expression of phosphorylated Stat3 in vitro and in vivo. CONCLUSION: Taken together, we conclude that NIF inhibits and reverses pulmonary fibrosis, and these results support NIF as a viable therapeutic option for IPF treatment.

Focus on the classical and non-classical functions of EZH2: Guide the development of inhibitors and degraders.

Enhancer of zeste homologue 2 (EZH2, also known as KMT6A) is found to be a member of the histone lysine methyltransferase family. An increasing number of studies have shown that in addition to methylating histones, EZH2 plays a vital role in a variety of ways. The methylated substrates of EZH2 also include GATA4, AR/AR-related proteins, STAT3, Talin protein, and RORα. Meanwhile, EZH2 has been reported to form complexes with some proteins to perform other important biological functions as well as methylation. These complexes include: the EZH2-RelA-RelB complex, EZH2-ER-ß-catenin complex, and ß-catenin-PAF-EZH2-Mediator complex. Herein, we focus on the classical and non-classical functions of EZH2, and summarize anti-EZH2 therapeutic strategies. Finally, we highlight that understanding the physiological and pathological functions of EZH2 in specific indications can help the development of inhibitors or degraders.

Repurposing of antipsychotic trifluoperazine for treating brain metastasis, lung metastasis and bone metastasis of melanoma by disrupting autophagy flux.

Targeted therapies and immunotherapy have brought substantial benefits to patients with melanoma. However, brain metastases remain the biggest threat to the survival and quality of life of melanoma patients. One of the major challenges to an effective therapy is the inability of drugs to penetrate the blood-brain barrier (BBB). Anti-schizophrenic drugs can cross the BBB, and many of them have demonstrated anti-cancer effects. Repurposing existing drugs for new clinical indications is an alluring strategy for anticancer drug discovery. Herein, we applied this strategy and screened a small collection of existing anti-schizophrenic drugs to use as anti-melanoma agents. Among them, trifluoperazine dihydrochloride (TFP) exhibited promising potencies for suppressing the growth and metastasis of melanoma, both in vitro and in vivo. TFP obviously suppressed the viability of melanoma cells within the micromolar range and inhibited the growth of melanoma in the subcutaneous mice models. Notably, intraperitoneal (i.p.) administration of TFP (40 mg/kg/day) obviously inhibited the growth of intra-carotid-injection established melanoma brain metastasis and extended the survival of brain metastasis-bearing mice. Moreover, TFP significantly suppressed lung metastasis and bone metastasis of melanoma in preclinical metastasis models. Mechanistically, TFP caused G0/G1 cell cycle arrest and mitochondrial-dependent intrinsic apoptosis of melanoma cells. In addition, TFP treatment increased the expression of microtubule associated protein 1 light chain 3 beta-II (LC3B-II) and p62 in vitro, suggesting an inhibition of autophagic flux. TFP decreased LysoTracker Red uptake after treatment, indicating impaired acidification of lysosomes. Moreover, the colocalization of LC3 with lysosomal-associated membrane protein 1 (LAMP1), a lysosome marker, was also suppressed after TFP treatment, suggesting that TFP might block the fusion of autophagosomes with lysosomes, which led to autophagosome accumulation. Taken together, our data highlight the potential of repurposing TFP as a new adjuvant drug for treating melanoma patients with brain, lung, and bone metastases.

Structure-guided discovery of novel potent and efficacious proteolysis targeting chimera (PROTAC) degrader of BRD4.

Bromodomain-containing protein 4 (BRD4) has been identified as a potential target in the treatment of many cancers and several BRD4 inhibitors have entered clinical studies. Previous studies have shown that BRD4 degraders have potential to overcome resistance to BRD4 inhibitors. However, most of the BRD4 degraders have poor solubility and bioavailability, one of which the reason is large molecular weight. Here, we describe the design, synthesis, and evaluation studies of a BRD4 degrader based on the proteolysis targeting chimeras (PROTAC) concept. Our efforts have led to the discovery of compound 15, which is a weak inhibitor and potent BRD4 degrader with a molecular weight of 821.8. In vitro, 15 can completely degrade BRD4 at nanomolar concentration, with DC50 = 0.25 and 3.15 nM in MV4-11 and RS4-11 cell lines, respectively. Further optimization of compound 15 may reduce its molecular weight and improve druggabillity, and provide a new choice for the treatment of cancer.

Synthesis and Biological Evaluation of Novel 4-(4-Formamidophenylamino)-N-methylpicolinamide Derivatives as Potential Antitumor Agents.

A novel series of 4-(4-formamidophenylamino)-N-methylpicolinamide derivatives were synthesized and evaluated against different tumor cell lines. Experiments in vitro showed that these derivatives could inhibit the proliferation of two kinds of human cancer cell lines (HepG2, HCT116) at low micromolar concentrations and the most potent analog 5q possessed broad-spectrum antiproliferative activity. Experiments in vivo demonstrated that 5q could effectively prolong the longevity of colon carcinoma-burdened mice and slow down the progression of cancer cells by suppression of angiogenesis and the induction of apoptosis and necrosis.

A novel fixed-dose combination treatment for chronic hepatitis C, based on NS5A inhibitor fopitasvir and NS5B inhibitor sofosbuvir.

Drug resistance caused by the extreme genetic variability of zhe hepatitis C virus has rendered effective combinations of drugs indispensable in the treatment of chronic hepatitis C (CHC). Herein, we developed a fixed-dose combination (FDC) treatment containing the NS5B inhibitor sofosbuvir (SOF) and the NS5A inhibitor fopitasvir (FOP). Then the dissolution behavior of FOP in FOP/SOF FDC was improved by co-micronizing FOP with lactose. The enhanced dissolution rate of FOP in the FDC was in good agreement with the behavior of the FOP singledrug tablet. In addition, pharmacokinetic studies showed that both FOP and SOF in the FDC exhibited similar characteristics (area under the curve, Cmax, Tmax, and T1/2) as those of tablets containing FOP or SOF alone. These results revealed that the FOP/SOF FDC represents a potential therapeutic option for the treatment of CHC.

Design and synthesis of (E)-1,2-diphenylethene-based EZH2 inhibitors.

Enhancer of zeste homolog 2 (EZH2) serves as the catalytic subunit of the polycomb repression complex 2 (PRC2), which is implicated in cancer progression metastasis and poor prognosis. Based on our EZH2 inhibitor SKLB1049 with low nanomolar activity, we extended the "tail" region to get a series of (E)-1,2-diphenylethene derivatives as novel EZH2 inhibitors. SAR exploration and preliminary assessment led to the discovery of the potent novel EZH2 inhibitor 9b (EZH2WT IC50 = 22.0 nM). Compound 9b inhibited the proliferation of WSU-DLCL2 and SU-DHL-4 cell lines (IC50 = 1.61 µM and 2.34 µM, respectively). The biological evaluation showed that 9b was a potent inhibitor for wild-type EZH2 and greatly reduced the overall levels of H3K27me3 in a concentration-dependent manner. Further study indicated that 9b could significantly induce apoptosis of SU-DHL-4 cells. These findings indicated that 9b would be an attractive lead compound for further optimization and evaluation.

Design, synthesis and structure-activity relationship study of piperazinone-containing thieno[3,2-d]pyrimidine derivatives as new PI3Kδ inhibitors.

Two classes of piperazinone-containing thieno[3,2-d]pyrimidines were designed and synthesized as new PI3Kδ inhibitors in this study. Detailed SAR study with respect to the piperazinone substituents at the 6-position of thieno[3,2-d]pyrimidine core demonstrated that piperazinone-containing thieno[3,2-d]pyrimidines would be more potent and selective for PI3Kδ than their piperazine counterparts, which led to the discovery of several potent PI3Kδ inhibitors with comparable or better antiproliferative activity against a panel of non-Hodgkin lymphoma (NHL) cell lines as compared with idelalisib. Our study will promote the development of new PI3Kδ inhibitors based on piperazinone-containing thieno[3,2-d]pyrimidine scaffold.

Design, synthesis and biological evaluation of a novel tubulin inhibitor SKLB0565 targeting the colchicine binding site.

A series of 3-(((9H-purin-6-yl) amino) methyl) pyridin-2(1H)-one derivatives were designed, synthesized and confirmed as tubulin polymerization inhibitors. All compounds were evaluated for their anti-proliferative activities on three colorectal carcinoma (CRC) cell lines. Among these compounds, SKLB0565 displayed noteworthy potency against eight CRC cell lines with IC50 values ranging from 0.012 µM and 0.081 µM. Besides, SKLB0565 inhibited tubulin polymerization, caused G2/M phase cell cycle arrest, depolarized mitochondria and induced cell apoptosis in CRC cells. Furthermore, SKLB0565 suppressed cell migration and disrupted the capillary tube formation of human umbilical vein endothelial cells (HUVECs). Our data clarified that SKLB0565 is a promising anti-tubulin agent for CRC therapy which is worthy of further evaluation.

Identification of a potent and selective phosphatidylinositol 3-kinase δ inhibitor for the treatment of non-Hodgkin's lymphoma.

PI3Kδ has proved to be an effective target for anti-lymphoma drugs. However, the application of current approved PI3Kδ inhibitors has been greatly limited due to their specific immune-mediated toxicity and increased risk of infection, it is necessary to develop more PI3Kδ inhibitors with new scaffold. In this study, SAR study with respect to piperazinone-containing purine derivatives led to the discovery of a potent and selective PI3Kδ inhibitor, 4-(cyclobutanecarbonyl)-1-((2-(2-ethyl-1H-benzo[d]imidazol-1-yl)-9-methyl-6-morpholino-9H-purin-8-yl)methyl)piperazin-2-one (WNY1613). WNY1613 exhibits good antiproliferative activity against a panel of non-Hodgkin's lymphoma (NHL) cell lines by inducing cancer cell apoptosis and inhibiting the phosphorylation of PI3K and MAPK downstream components. In addition, it can also prevent the tumor growth in both SU-DHL-6 and JEKO-1 xenograft models without observable toxicity. WNY1613 thus could be developed as a promising candidate for the treatment of NHL after subsequent extensive pharmacodynamics and pharmacokinetics investigation.

Preclinical evaluation of Amphihevir, a first-in-class clinical Hepatitis C virus NS4B inhibitor.

Amphihevir, a benzofuran derivative, is the first reported NS4B inhibitor that has advanced to clinical trials (currently in Phase Ib). Here, we report the results of a preclinical study of its potency, toxicity, selectivity, DMPK, and safety profiles. Amphihevir displayed good antiviral activities against genotype 1a (EC50=0.34 nM) and genotype 1b (EC50=1.97 nM) replicons and evident cytotoxicity in twelve strains of cell lines derived from animals and humans. Amphihevir was found to be inactive against other viruses, human kinases, and GPCRs, which implies its good selectivity. A 9-day long-term treatment of genotype 1b replicon with Amphihevir resulted in a 3.8 Log10 decline of the hepatitis C viral RNA at a concentration of 25×EC90 Drug resistance screening showed that mutations occurred at H94, F98, and V105 of NS4B, which mediated the resistance to Amphihevir. This result suggests that NS4B is the main target of Amphihevir. There was no cross-resistances between Amphihevir and NS5A, NS3/4A, and NS5B inhibitors, suggesting that Amphihevir on combination of other anti- hepatitis C virus drugs could treat hepatitis C, as proven by studies of Amphihevir and other hepatitis C virus inhibitors. Pharmacokinetic studies demonstrated that Amphihevir has good oral bioavailability and appropriate T1/2 in rats and dogs, thereby supporting its use once per day. Finally, Amphihevir showed good safety profiles in rats and dogs. The results shed light on the use of Amphihevir as a potential treatment option for chronic hepatitis C patients.

Discovery and evaluation of novel nitrodihydroimidazooxazoles as promising anti-tuberculosis agents.

New analogues of antitubercular drug Delamanid were prepared, seeking drug candidates with enhanced aqueous solubility and high efficacy. The strategy involved replacement of phenoxy linker proximal to the 2-nitroimidazooxazole of Delamanid by piperidine fused 5 or 6-membered ring heterocycles (ring A). The new compounds were all more hydrophilic than Delamanid, and several class of analogues showed remarkable activities against M. bovis. And among these series, the tetrahydro-naphthyridine-linked nitroimidazoles displayed excellent antimycobacterial activity against both replicating (MABA) and nonreplicating (LORA) M. tb H37Rv and low cytotoxicity. Compared to Delamanid, these new compounds (6, 7, 45) demonstrated dramatically improved physicochemical properties and are suitable for further in vitro and in vivo evaluation.

Design, synthesis and biological evaluation of 3,5-dimethylisoxazole and pyridone derivatives as BRD4 inhibitors.

Bromodomain-containing protein 4 (BRD4), a member of the bromodomain and extra-terminal (BET) family, has been recognized as an attractive candidate target for the treatment targeting gene transcription in several types of cancers. In this study, two types of novel compounds were designed, synthesized and evaluated as BRD4 inhibitors. Therein, pyridone derivatives were more effective against BRD4 protein and human leukemia cell lines MV4-11. Among them, compounds 11d, 11e and 11f were the most potential ones with IC50 values of 0.55 µM, 0.86 µM and 0.80 µM against BRD4, and exhibited remarkable antiproliferative activities against MV4-11 cells with IC50 values of 0.19 µM, 0.32 µM and 0.12 µM, respectively. Moreover, in western blot assay, compound 11e induced down-regulation of C-Myc, which is a significant downstream gene of BRD4. Cell cycle analysis assay also showed that compound 11e could block MV4-11 cells at G0/G1 phase. Taken together, our results suggested that compound 11e and its derivatives were a class of novel structural potential BRD4 inhibitors and could serve as lead compounds for further exploration.

Natural product pectolinarigenin exhibits potent anti-metastatic activity in colorectal carcinoma cells in vitro and in vivo.

Colorectal carcinoma (CRC) is one of the most common cancers with high metastatic potential, explaining why identifying new drug candidates that inhibit tumour metastasis is an urgent need. The aim of this study was to evaluate the biological activities of pectolinarigenin (PEC, a natural flavonoid present in Cirsium chanroenicum) in CRC in vitro and in vivo and to determine its underlying mechanism of action. Here, we observed that treatment with PEC could inhibit cell viability and induce apoptosis in cancer cells in a concentration- and time-dependent manner. The occurrence of apoptosis was associated with activation of caspase-3 and Bax and decreased expression of Bcl-2. In addition, PEC markedly impaired CRC cell migration and invasion by downregulating the expression of matrix metalloproteinase (MMP-9) and phosphorylated-Stat3Tyr705. Moreover, our studies showed that PEC inhibited abdominal metastasis models of murine colorectal cancer. In addition, histological and immunohistochemical analyses revealed a decrease in Ki67-positive cells, MMP9-positive cells and p-Stat3Tyr705 cells upon treatment with PEC compared to control samples. Furthermore, PEC reduced the number of myeloid-derived suppressor cells (MDSCs) in the blood and tumours, which was accompanied by the increased infiltration of CD8+T cells in the blood. Taken together, our findings suggested that PEC could be used as a natural drug to inhibit CRC metastasis.

Synthesis and biological evaluation of benzomorpholine derivatives as novel EZH2 inhibitors for anti-non-small cell lung cancer activity.

The histone lysine methyltransferase EZH2 has been reported to play important roles in cancer aggressiveness, metastasis and poor prognosis. In this study, a series of benzomorpholine derivatives were synthesized and biologically evaluated as EZH2 inhibitors. The target compounds were obtained in good yields from 3-amino-5-bromo-2-hydroxybenzoic acid via cyclization, Suzuki coupling and amidation as the key steps. A preliminary optimization study led to the discovery of several potent novel EZH2 inhibitors (6b, 6c, 6x and 6y). Moreover, 6y inhibited the A549 and NCI-H1975 cell lines (IC50 = 1.1 µM and 1.1 µM, respectively). Further studies indicated that 6y can reduce EZH2 expression in intact cells and cause cell arrest in the G2/M phase.

Discovery and Structure-Resistance Relationship Study of New Thieno[2,3-b] Pyridine HCV NS4B Inhibitors.

The non-structural protein 4B (NS4B) of hepatitis C virus (HCV) has emerged as a promising target for chronic hepatitis C treatment. The thieno[2,3-b]pyridine HCV inhibitor 2 has demonstrated properties as a NS4B inhibitor. Subsequent hybridization of 2 with our recently published imidazo[2,1-b]thiazole NS4B inhibitor 3 resulted in the discovery of several more potent compounds with sub-micromolar EC50 against HCV genotype 1b replicon. More importantly, the resistant profile study of the new synthesized HCV inhibitors illustrated that the bicyclic scaffold would mediate the resistance of H3R and Q26R mutations, while the piperazinone motif would mediate the resistance of H94R, F98C and V105M mutations, and the C3- amino group would disrupt the interaction between piperazinone motif and NS4B. This structure-resistance relationship detail could help us to develop new NS4B inhibitors with higher resistant barrier in the future.