Remodeling the immune microenvironment for gastric cancer therapy through antagonism of prostaglandin E2 receptor 4.

Gastric cancer is highly prevalent among digestive tract tumors. Due to the intricate nature of the gastric cancer immune microenvironment, there is currently no effective treatment available for advanced gastric cancer. However, there is promising potential for immunotherapy targeting the prostaglandin E2 receptor subtype 4 (EP4) in gastric cancer. In our previous study, we identified a novel small molecule EP4 receptor antagonist called YY001. Treatment with YY001 alone demonstrated a significant reduction in gastric cancer growth and inhibited tumor metastasis to the lungs in a mouse model. Furthermore, administration of YY001 stimulated a robust immune response within the tumor microenvironment, characterized by increased infiltration of antigen-presenting cells, T cells, and M1 macrophages. Additionally, our research revealed that YY001 exhibited remarkable synergistic effects when combined with the PD-1 antibody and the clinically targeted drug apatinib, rather than fluorouracil. These findings suggest that YY001 holds great promise as a potential therapeutic strategy for gastric cancer, whether used as a standalone treatment or in combination with other drugs.

A small molecule BCL6 inhibitor as chemosensitizers in acute myeloid leukemia.

BCL6 is a transcriptional repressor that regulates multiple genes involved in immune cell differentiation, DNA damage repair, cell cycle, and apoptosis, and is a carcinogenic factor in acute myeloid leukemia (AML). AML is one of the four major types of leukemia with the 5-year survival rate of patients is less than 20% and chemotherapy resistance remains the major obstacle to the treatment failure of AML. We identified WK499, a small molecule compound that can bind to BCL6BTB structure. Treatment with WK499 hinders the interactions between BCL6 with its corepressor proteins, resulting in a remarkable change of BCL6 downstream genes and anti-proliferative effects in AML cells, and inducing cell cycle arrest and apoptosis. We verified that AraC and DOXo could induce BCL6 expression in AML cells, and found that WK499 had a synergistic effect when combined with chemotherapeutic drugs. We further proved that WK499 and AraC could achieve a better result of inhibiting the growth of AML in vivo. These findings indicate that WK499, a small molecule inhibitor of BCL6, not only inhibits the proliferation of AML, but also provides an effective therapeutic strategy for increasing AML sensitivity to chemotherapy.

Single-Cell Analysis Reveals EP4 as a Target for Restoring T-Cell Infiltration and Sensitizing Prostate Cancer to Immunotherapy.

PURPOSE: Immunotherapies targeting immune checkpoint molecules have shown promising treatment for a subset of cancers; however, many "cold" tumors, such as prostate cancer, remain unresponsive. We aimed to identify a potential targetable marker relevant to prostate cancer and develop novel immunotherapy. EXPERIMENTAL DESIGN: Analysis of transcriptomic profiles at single-cell resolution was performed in clinical patients' samples, along with integrated analysis of multiple RNA-sequencing datasets. The antitumor activity of YY001, a novel EP4 antagonist, combined with anti-programmed cell death protein 1 (PD-1) antibody was evaluated both in vitro and in vivo. RESULTS: We identified EP4 (PTGER4) as expressed in epithelial cells and various immune cells and involved in modulating the prostate cancer immune microenvironment. YY001, a novel EP4 antagonist, inhibited the differentiation, maturation, and immunosuppressive function of myeloid-derived suppressor cells (MDSC) while enhancing the proliferation and anticancer functions of T cells. Furthermore, it reversed the infiltration levels of MDSCs and T cells in the tumor microenvironment by overturning the chemokine profile of tumor cells in vitro and in vivo. The combined immunotherapy demonstrated a robust antitumor immune response as indicated by the robust accumulation and activation of CD8+ cytotoxic T cells, with a significantly decreased MDSC ratio and reduced MDSC immunosuppression function. CONCLUSIONS: Our study identified EP4 as a specific target for prostate cancer immunotherapy and demonstrated that YY001 inhibited the growth of prostate tumors by regulating the immune microenvironment and strongly synergized with anti-PD-1 antibodies to convert completely unresponsive prostate cancers into responsive cancers, resulting in marked tumor regression, long-term survival, and lasting immunologic memory.

Effect of Finely Ground Limestone and Dolomite on Compression Strength and Reduction Swelling of Vanadium-Titanium Pellets.

Vanadium-titanium magnetite (VTM) is an important raw material for ironmaking under the situation of increasingly demanding scarce resources. To further improve the metallurgical properties of pellets, and to satisfy the requirements of blast furnace slag basicity, finely ground dolomite and limestone have been added to the pellet. In this study, the effect of finely ground dolomite and limestone on the metallurgical properties (green pellet drop strength, cold compression strength, reduction swelling index, and microscopic mineral structure) of VTM pellets were investigated. With the addition of finely ground dolomite and limestone, the drop strength of the green pellet was improved. The effect of adding finely ground limestone was greater than adding finely ground dolomite. Adding more finely ground dolomite and limestone compared to pellets without limestone and dolomite, the cold compression strength was decreased, which was attributed to the decomposition of limestone and dolomite during the induration of pellets. With the addition of dolomite, the reduction swelling index (RSI) increased firstly and then decreased. When the basicity of the pellet was 0.54 to 0.94, the slag phase with the lowest melting point was formed, corresponding to the maximum of the reduction swelling index. For the pellets with added limestone, the reduction swelling of the pellets deteriorated. The reduction index of the pellets increased and reached the maximum (26.6%) at a basicity of 1.54, which belongs to abnormal swelling.

Regression of Castration-Resistant Prostate Cancer by a Novel Compound HG122.

Prostate cancer (PCa) is a common aggressive disease worldwide which usually progresses into incurable castration-resistant prostate cancer (CRPC) in most cases after 18-24 months treatment. Androgen receptor (AR) has been considered as a crucial factor involved in CRPC and the study of AR as a potential therapeutic target in CRPC may be helpful in disease control and life-cycle management. In this study, we identified a potent small molecule compound, HG122, that suppressed CRPC cells proliferation and metastasis, and inhibited tumor growth both in subcutaneous and orthotopic tumor model. In addition, HG122 reduced the mRNA expression of PSA and TMPRSS2 which are target genes of AR, resulting in cell growth inhibition and metastasis suppression of CRPC, without affecting the expression of AR mRNA level. Mechanically, HG122 promoted AR protein degradation through the proteasome pathway impairing the AR signaling pathway. In conclusion, HG122 overcomes enzalutamide (ENZ) resistance in CRPC both in vitro and in vivo, thus suggesting HG122 is a potential candidate for the clinical prevention and treatment of CRPC.

Targeting STAT3 by a small molecule suppresses pancreatic cancer progression.

Pancreatic cancer is lethal in over 90% of cases since it is resistant to current therapeutic strategies. The key role of STAT3 in promoting pancreatic cancer progression has been proven, but effective interventions that suppress STAT3 activities are limited. The development of novel anticancer agents that directly target STAT3 may have potential clinical benefits for pancreatic cancer treatment. Here, we report a new small-molecule inhibitor (N4) with potent antitumor bioactivity, which inhibits multiple oncogenic processes in pancreatic cancer. N4 blocked STAT3 and phospho-tyrosine (pTyr) peptide interactions in fluorescence polarization (FP) assay, specifically abolished phosphor-STAT3 (Tyr705), and suppressed expression of STAT3 downstream genes. The mechanism involved the direct binding of N4 to the STAT3 SH2 domain, thereby, the STAT3 dimerization, STAT3-EGFR, and STAT3-NF-κB cross-talk were efficiently inhibited. In animal models of pancreatic cancer, N4 was well tolerated, suppressed tumor growth and metastasis, and significantly prolonged survival of tumor-bearing mice. Our results offer a preclinical proof of concept for N4 as a candidate therapeutic compound for pancreatic cancer.

Reprogramming immunosuppressive myeloid cells facilitates immunotherapy for colorectal cancer.

Immune checkpoint blockade (ICB) has a limited effect on colorectal cancer, underlining the requirement of co-targeting the complementary mechanisms. Here, we identified prostaglandin E2 (PGE2 ) receptor 4 (EP4) as the master regulator of immunosuppressive myeloid cells (IMCs), which are the major driver of resistance to ICB therapy. PGE2 -bound EP4 promotes the differentiation of immunosuppressive M2 macrophages and myeloid-derived suppressor cells (MDSCs) and reduces the expansion of immunostimulated M1 macrophages. To explore the immunotherapeutic role of EP4 signaling, we developed a novel and selective EP4 antagonist TP-16. TP-16 effectively blocked the function of IMCs and enhanced cytotoxic T-cell-mediated tumor elimination in vivo. Cell co-culture experiments revealed that TP-16 promoted T-cell proliferation, which was impaired by tumor-derived CD11b+ myeloid cells. Notably, TP-16 and anti-PD-1 combination therapy significantly impeded tumor progression and prolonged mice survival. We further demonstrated that TP-16 increased responsiveness to anti-PD-1 therapy in an IMC-related spontaneous colorectal cancer mouse model. In summary, this study demonstrates that inhibition of EP4-expressing IMCs may offer a potential strategy for enhancing the efficacy of immunotherapy for colorectal cancer.

Novel Long Non-coding RNA lncAMPC Promotes Metastasis and Immunosuppression in Prostate Cancer by Stimulating LIF/LIFR Expression.

Long non-coding RNAs (lncRNAs) participate in the development and progression of prostate cancer (PCa). We aimd to identify a novel lncRNA, named lncRNA activated in metastatic PCa (lncAMPC), and investigate its mechanisms and clinical significance in PCa. First, the biological capacity of lncAMPC in PCa was demonstrated both in vitro and in vivo. The lncAMPC was overexpressed in tumor tissue and urine of metastatic PCa patients and promoted PCa tumorigenesis and metastasis. Then, a mechanism study was conducted to determine how the lncAMPC-activated pathway contributed to PCa metastasis and immunosuppression. In the cytoplasm, lncAMPC upregulated LIF expression by sponging miR-637 and inhibiting its activity. In the nucleus, lncAMPC enhanced LIFR transcription by decoying histone H1.2 away from the upstream sequence of the LIFR gene. The lncAMPC-activated LIF/LIFR expressions stimulated the Jak1-STAT3 pathway to simultaneously maintain programmed death-ligand 1 (PD-L1) protein stability and promote metastasis-associated gene expression. Finally, the prognostic value of the expression of lncAMPC and its downstream genes in PCa patients was evaluated. High LIF/LIFR levels indicated shorter biochemical recurrence-free survival among patients who underwent radical prostatectomy. Therefore, the lncAMPC/LIF/LIFR axis plays a critical role in PCa metastasis and immunosuppression and may serve as a prognostic biomarker and potential therapeutic target.

Determining the Drug-Like Properties of Ailanthone, a Novel Chinese Medicine Monomer with Anti-CRPC Activity.

Approximately 40% of compounds with therapeutic potential cannot be successfully developed into drugs owing to their poor pharmaceutical properties, emphasising the need to profile their drug-like properties as early as possible during preclinical development. This study aimed to evaluate the drug-like properties of ailanthone, a novel Chinese medicine monomer that was shown to have activity against castration-resistant prostate cancer tumour growth and metastasis in our previous study. The drug-like properties detected in the present study included effects on permeability, liver microsome stability, plasma protein binding rate, plasma stability, and human ether-à-go-go-related gene inhibition. Additionally, the following results were obtained: the efflux ratio of ailanthone was > 32 during permeability detection; the half-life and intrinsic clearance (Clint) in mouse, rat, and human liver microsomes were > 145 min and < 9.6 µL/min/mg protein, respectively. The Clint(liver) of ailanthone was < 38.0, < 17.3, and < 8.6 mL/min/kg body weight in mice, rats, and humans, respectively. The plasma protein binding percentage of ailanthone was 16.6 ± 4.2% in human plasma, with 62.5% remaining at 120 min after incubation. The IC50 value of ailanthone for the human ether-à-go-go-related gene channels was > 30 µM. Collectively, these results and those from our previous study indicate that the pharmacokinetic properties of ailanthone are suitable for the potential development of this compound as an oral or intravenous drug for the treatment of castration-resistant prostate cancer.

Regression of castration-resistant prostate cancer by a novel compound QW07 targeting androgen receptor N-terminal domain.

Androgen deprivation therapy (ADT) via surgical or chemical castration frequently fails to halt lethal castration-resistant prostate cancer (CRPC), which is induced by multiple mechanisms involving constitutive androgen receptor (AR) splice variants, AR mutation, and/or de novo androgen synthesis. The AR N-terminal domain (NTD) possesses most transcriptional activity and is proposed as a potential target for CRPC drug development. We constructed a screening system targeting AR-NTD transcription activity to screening a compound library and identified a novel small molecule compound named QW07. The function evaluation and mechanism investigation of QW07 were carried out in vitro and in vivo. QW07 bound to AR-NTD directly, blocked the transactivation of AR-NTD, blocked interactions between co-regulatory proteins and androgen response elements (AREs), inhibited the expression of genes downstream of AR, and inhibited prostate cancer growth in vitro and in vivo. QW07 was demonstrated as an AR-NTD-specific antagonist with the potential to inhibit both canonical and variant-mediated AR signaling to regress the CRPC xenografts and is proposed as a lead compound for a specific antagonist targeting AR-NTD.

A novel BMI-1 inhibitor QW24 for the treatment of stem-like colorectal cancer.

BACKGROUND: Cancer-initiating cell (CIC), a functionally homogeneous stem-like cell population, is resonsible for driving the tumor maintenance and metastasis, and is a source of chemotherapy and radiation-therapy resistance within tumors. Targeting CICs self-renewal has been proposed as a therapeutic goal and an effective approach to control tumor growth. BMI-1, a critical regulator of self-renewal in the maintenance of CICs, is identified as a potential target for colorectal cancer therapy. METHODS: Colorectal cancer stem-like cell lines HCT116 and HT29 were used for screening more than 500 synthetic compounds by sulforhodamine B (SRB) cell proliferation assay. The candidate compound was studied in vitro by SRB cell proliferation assay, western blotting, cell colony formation assay, quantitative real-time PCR, flow cytometry analysis, and transwell migration assay. Sphere formation assay and limiting dilution analysis (LDA) were performed for measuring the effect of compound on stemness properties. In vivo subcutaneous tumor growth xenograft model and liver metastasis model were performed to test the efficacy of the compound treatment. Student's t test was applied for statistical analysis. RESULTS: We report the development and characterization of a small molecule inhibitor QW24 against BMI-1. QW24 potently down-regulates BMI-1 protein level through autophagy-lysosome degradation pathway without affecting the BMI-1 mRNA level. Moreover, QW24 significantly inhibits the self-renewal of colorectal CICs in stem-like colorectal cancer cell lines, resulting in the abrogation of their proliferation and metastasis. Notably, QW24 significantly suppresses the colorectal tumor growth without obvious toxicity in the subcutaneous xenograft model, as well as decreases the tumor metastasis and increases mice survival in the liver metastasis model. Moreover, QW24 exerts a better efficiency than the previously reported BMI-1 inhibitor PTC-209. CONCLUSIONS: Our preclinical data show that QW24 exerts potent anti-tumor activity by down-regulating BMI-1 and abrogating colorectal CICs self-renewal without obvious toxicity in vivo, suggesting that QW24 could potentially be used as an effective therapeutic agent for clinical colorectal cancer treatment.

A novel synthetic small molecule YF-452 inhibits tumor growth through antiangiogenesis by suppressing VEGF receptor 2 signaling.

Tumor angiogenesis is characterized by abnormal vessel morphology, endowing tumor with highly hypoxia and unresponsive toward treatment. To date, mounting angiogenic factors have been discovered as therapeutic targets in antiangiogenic drug development. Among them, vascular endothelial growth factor receptor 2 (VEGFR2) inhibitors exerts potent antiangiogenic activity in tumor therapy. Therefore, it may provide a valid strategy for cancer treatment through targeting the tumor angiogenesis via VEGFR2 pathway. In this study, we established a high-profile compounds library and certificated a novel compound named N-(N-pyrrolidylacetyl)-9-(4-bromobenzyl)-1,3,4,9-tetrahydro-ß-carboline (YF-452), which remarkably inhibited the migration, invasion and tube-like structure formation of human umbilical vein endothelial cells (HUVECs) with little toxicity invitro. Rat thoracic aorta ring assay indicated that YF-452 significantly blocked the formation of microvascular exvivo. In addition, YF-452 inhibited angiogenesis in chick chorioallantoic membrane (CAM) and mouse corneal micropocket assays. Moreover, YF-452 remarkably suppressed tumor growth in xenografts mice model. Furthermore, investigation of molecular mechanism revealed that YF-452 inhibited VEGF-induced phosphorylation of VEGFR2 kinase and the downstream protein kinases including extracellular signal regulated kinase (ERK), focal adhesion kinase (FAK) and Src. These results indicate that YF-452 inhibits angiogenesis and may be a potential antiangiogenic drug candidate for cancer therapy.

Ailanthone targets p23 to overcome MDV3100 resistance in castration-resistant prostate cancer.

Androgen receptor (AR) antagonist MDV3100 is the first therapeutic approach in treating castration-resistant prostate cancer (CRPC), but tumours frequently become drug resistant via multiple mechanisms including AR amplification and mutation. Here we identify the small molecule Ailanthone (AIL) as a potent inhibitor of both full-length AR (AR-FL) and constitutively active truncated AR splice variants (AR-Vs). AIL binds to the co-chaperone protein p23 and prevents AR's interaction with HSP90, thus resulting in the disruption of the AR-chaperone complex followed by ubiquitin/proteasome-mediated degradation of AR as well as other p23 clients including AKT and Cdk4, and downregulates AR and its target genes in PCa cell lines and orthotopic animal tumours. In addition, AIL blocks tumour growth and metastasis of CRPC. Finally, AIL possesses favourable drug-like properties such as good bioavailability, high solubility, lack of CYP inhibition and low hepatotoxicity. In general, AIL is a potential candidate for the treatment of CRPC.

Synthesis of novel diterpenoid analogs with in-vivo antitumor activity.

A lead compound 7 has antitumor effect, which was discovered by screening our small synthetic natural product-like compound (NPL) library. Based on the lead compound, a series of novel tricyclic diterpene analogs were synthesized and investigated for their activity against the growth of various tumor cell lines using the sulforhodamine B (SRB) assay. To our delight, most aromatic amide compounds exhibited more potent antitumor activity than the lead compound. The most active compound 19 (QW30) showed an average IC50 0.33 µM, which was 15-fold more potent than the lead compound. Most of the compounds with potent antitumor activity displayed less toxic on normal human fibroblasts (HAF) in comparison with the tumor cell lines. Especially 19, its selectivity indexes (SI) between HAF and cancer cell lines was 17.3 times better than the positive control compound podophyllotoxin. The apoptosis, colony formation and transwell migration assays of 7 and 19 were performed on T47D cell line. The in-vivo antitumor effect of 19 was also observed in T47D tumor-bearing mice without obvious toxicity.

Synthesis and biological evaluation of D-ring fused 1,2,3-thiadiazole dehydroepiandrosterone derivatives as antitumor agents.

A series of D-ring fused 1,2,3-thiadiazole DHEA derivatives were synthesized and investigated for their activity against the growth of various tumor cell lines using the sulforhodamine B (SRB) assay. It is amazing that for these compounds, T47D cell line was much more sensitive than other tumor cell lines. The most potent saturated N-heterocyclic derivatives showed similar antitumor effect with the positive control compound ADM (adriamycin) on T47D cells, that was 44-60 folds more potent than the lead compound DHEA. Most compounds with potent antitumor activity displayed low toxicity on normal human fibroblasts (HAF). Especially compound 25 (CH33) showed an IC50 of 0.058 µM on T47D cells and its selectivity index (SI) between HAF and T47D was 364, which was 214 folds better than ADM (SI = 1.7). The apoptosis, colony formation and transwell migration assays of 25 were performed on T47D cell line. The primary mechanism study showed that 25 caused a dose-dependent induction of apoptosis, and induced phosphorylation of EphA2 and EphB3 in T47D cells. The in vivo antitumor effect of 25 was also observed in T47D tumor-bearing mice without obvious toxicity.

A hybrid of thiazolidinone with the hydroxamate scaffold for developing novel histone deacetylase inhibitors with antitumor activities.

A series of novel histone deacetylase (HDAC) inhibitors were designed, synthesized and evaluated based on the strategies of a hybrid of the classic pharmacophore of HDAC inhibitors with the thiazolidinone scaffold. Some of the compounds 12i showed potent HDAC1 inhibition with nM IC50 values, more importantly, compound displayed much better anti-metastatic effects than vorinostat (SAHA) against migration of the A549 cell line. Further mechanism exploration implied that compound 12i may inhibit tumor metastasis via modulating the epithelial-mesenchymal transition (EMT) and upregulating the acetylation of α-tubulin.

LG308, a Novel Synthetic Compound with Antimicrotubule Activity in Prostate Cancer Cells, Exerts Effective Antitumor Activity.

Microtubule plays many different essential roles in the process of tumorigenesis in many eukaryotes, and targeting mitotic progression by disturbing microtubule dynamics is used as a common strategy for cancer treatment. Microtubule-targeted drugs, including paclitaxel and Vinca alkaloids, were previously considered to work primarily by increasing or decreasing the cellular microtubule mass. The tubulin/microtubule system, which is an integral component of the cytoskeleton, is a therapeutic target for prostate cancer. In this study, we found a novel synthetic compound, 8-fluoro-N-phenylacetyl-1, 3, 4, 9-tetrahydro-ß-carboline (LG308), which disrupted the microtubule organization via inhibiting the polymerization of microtubule in PC-3M and LNCaP prostate cancer cell lines. Further study proved that LG308 induced mitotic phase arrest and inhibited G2/M progression significantly in LNCaP and PC-3M cell lines in a dose-dependent manner, and these were associated with the upregulation of cyclin B1 and mitotic marker MPM-2 and the dephosphorylation of cdc2. Besides, the cell proliferation and colony formation of PC-3M and LNCaP cells were effectively inhibited by LG308. Furthermore, LG308 induced apoptosis and cell death in PC-3M and LNCaP cell lines in vitro. In vivo, LG308 dramatically suppressed the growth and metastasis of prostate cancer in both xenograft and orthotopic models. All these data indicate that LG308 is a promising anticancer candidate with antimitotic activity for the treatment of prostate cancer.

Lycorine is a novel inhibitor of the growth and metastasis of hormone-refractory prostate cancer.

Lycorine, a natural alkaloid extracted from the Amaryllidaceae plant family, has been reported to exhibit a wide range of physiological effects, including the potential effect against cancer. However, the anti-prostate cancer (PCa) efficacy of Lycorine remains unrevealed. In this context, we figured out Lycorine's anti-proliferative and anti-migratory properties for PCa treatment. Lycorine inhibited proliferation of various PCa cell lines, induced cell apoptosis and cell death. Here we showed that Lycorine decreased proliferation, migration, invasion, survival and EMT of prostate cancer cell lines. Subcutaneous and orthotopic xenotransplantations by ectopic implantation of the human hormone-refractory PC-3M-luc cells were used to confirm in vivo anticancer effects of Lycorine. Lycorine inhibited both growth and metastasis in multiple organs (liver, lung, kidney, spleen and bone) in vivo and improved mice survival. Lycorine prevented EGF-induced JAK/STAT signaling. Importantly, anti-cancer effects of Lycorine were dependent on STAT expression. We suggest that Lycorine is a potential therapeutic in prostate cancer.

Synthesis of novel heterocyclic ring-fused 18ß-glycyrrhetinic acid derivatives with antitumor and antimetastatic activity.

Glycyrrhetinic acid (GA) is one of the most important triterpenoic acids shows many pharmacological effects, especially antitumor activity. GA triggers apoptosis in various tumor cell lines. However, the antitumor activity of GA is weak, thus the synthesis of new synthetic analogs with enhanced potency is needed. By introducing various five-member fused heterocyclic rings at C-2 and C-3 positions, 18 novel GA derivatives were obtained. These compounds were evaluated for their inhibitory activity against the growth of eight different tumor cell lines using a SRB assay. The most active compound 37 showed IC50 between 5.19 and 11.72 µm, which was about 11-fold more potent than the lead compound GA. An apoptotic effect of GA and 37 was determined using flow cytometry and trypan blue exclusion assays. We also demonstrated here for the first time that GA and the synthetic derivatives exhibited inhibitory effect on migration of the tested tumor cells, especially 37 which was about 20-fold more potent than GA on antimetastatic activity.