Targeting Trop2 by Bruceine D suppresses breast cancer metastasis by blocking Trop2/ß-catenin positive feedback loop.

INTRODUCTION: Tumor-associated calcium signal transducer 2 (Trop2) has been used as a transport gate for cytotoxic agents into cells in antibody-drug conjugate designs because of its expression in a wide range of solid tumors. However, the specific role of Trop2 itself in breast cancer progression remains unclear and small molecules targeting Trop2 have not yet been reported. OBJECTIVES: To screen small molecules targeting Trop2, and to reveal its pharmacological effects and the molecular mechanisms of action. METHODS: Small molecule targeting Trop2 was identified by cell membrane chromatography, and validated by cellular thermal shift assay and point mutation analyses. We investigated the pharmacological effects of Trop2 inhibitor using RNA-seq, human foreskin fibroblast (HFF)-derived extracellular matrix (ECM), Matrigel drop invasion assays, colony-forming assay, xenograft tumor model, 4T1 orthotopic metastasis model and 4T1 experimental metastasis model. The molecular mechanism was determined using immunoprecipitation, mass spectrometry, immunofluorescence, immunohistochemistry and Western blotting. RESULTS: Here we identified Bruceine D (BD) as the inhibitor of Trop2, and demonstrated anti-metastasis effects of BD in breast cancer. Notably, Lys307 and Glu310 residues of Trop2 acted as critical sites for BD binding. Mechanistically, BD suppressed Trop2-induced cancer metastasis by blocking the formation of Trop2/ß-catenin positive loop, in which the Trop2/ß-catenin complex prevented ß-catenin from being degraded via the ubiquitin-proteosome pathway. Destabilized ß-catenin caused by BD reduced nucleus translocation, leading to the reduction of transcription of Trop2, the reversal of epithelial-mesenchymal transition (EMT) process, and the inhibition of ECM remodeling, further inhibiting cancer metastasis. Additionally, the inhibitory effects of BD on lung metastatic colonization and the beneficial effects of BD on prolongation of survival were validated in 4T1 experimental metastasis model. CONCLUSIONS: These results support the tumor-promoting role of Trop2 in breast cancer by stabilizing ß-catenin in Trop2/ß-catenin positive loop, and suggest Bruceine D as a promising candidate for Trop2 inhibition.

Cantharidin induces apoptosis of human triple negative breast cancer cells through mir-607-mediated downregulation of EGFR.

BACKGROUND: Triple negative breast cancer (TNBC) is a major subtype of breast cancer, with limited therapeutic drugs in clinical. Epidermal growth factor receptor (EGFR) is reported to be overexpressed in various TNBC cells. Cantharidin is an effective ingredient in many clinical traditional Chinese medicine preparations, such as Delisheng injection, Aidi injection, Disodium cantharidinate and vitamin B6 injection. Previous studies showed that cantharidin had satisfactory pharmacological activity on a variety of tumors. In this study, we aimed to study the therapeutic potential of cantharidin for TNBC treatment by targeting EGFR, and expound its novel regulator miR-607. METHODS: The effect of cantharidin on breast cancer in vivo was evaluated by 4T1 mice model. Then the effects of cantharidin on TNBC cells was assessed by the MTT, colony formation, and AnnexinV-PE/7AAD staining. Cantharidin acts on EGFR were verified using the cell membrane chromatography, RT-PCR, Western blotting, MTT, and so on. Mechanistic studies were explored by dual-luciferase report assay, RT-PCR, western blotting, and immunofluorescence staining assay. RESULTS: Cantharidin inhibited TNBC cell growth and induce apoptosis by targeting EGFR. miR-607 was a novel EGFR regulator and exhibited suppressive functions on TNBC cell behaviors. Mechanistic study showed that cantharidin blocked the downstream PI3K/AKT/mTOR and ERK/MAPK signaling pathway. CONCLUSION: Our results revealed that cantharidin may be served as a potential candidate for TNBC treatment by miR-607-mediated downregulation of EGFR.

Role of NLRP3 inflammasome activation in HCC cell progression.

Hepatocellular carcinoma (HCC) is a globally prevalent and fatal malignancy worldwide, and identifying therapeutic strategies is time-consuming. Numerous reports have suggested the involvement of the NLRP3 inflammasome in the progression of various cancers. However, the detailed mechanisms underlying the role of NLRP3 inflammasome in HCC progression remain unclear. In this study, we observed low expression levels of the NLRP3 inflammasome in a subset of HCC cells. Furthermore, we demonstrated that the NLRP3 inflammasome can be activated by LPS + ATP through the nuclear factor kappa B signaling pathway, as confirmed by western blotting and immunofluorescence staining. To assess the impact of NLRP3 inflammasome activation on HCC cell behavior, we employed Edu staining, cell cycle assay, Annexin V/PI staining, and wound healing assay. Our results revealed that NLRP3 inflammasome activation inhibited the proliferation of Bel-7402 and SMMC-7721 cells, arrested the cell cycle at the G1 phase, and suppressed cell migration, while apoptosis remained unaffected. In summary, our findings suggest that targeting the NLRP3 inflammasome could have therapeutic potential for HCC.

Identification and analysis of anti-tumor effective substances in Yangzheng Mixture.

Yangzheng Mixture is a traditional Chinese medicine used in clinical practice as an adjuvant therapy for tumors. However, little is known about its active components in tumor treatment. The purpose of this study was to explore the potential anti-tumor components of Yangzheng Mixture to better promote its clinical application. Using LC-MS/MS, 43 components were detected in concentrated Yangzheng Mixture. Six components, comprising astragaloside, calycosin, formononetin, isoquercitrin, ononin, and calycosin-7-O-ß-D-glucoside, were identified in rat plasma. The cancer cell absorption assay showed that the intracellular concentration of four components, calycosin, calycosin-7-O-ß-D-glucoside, formononetin, and ononin, increased with extended incubation time and demonstrated potential anti-tumor effects. The MTT assay results confirmed that Yangzheng Mixture inhibited different tumor cells proliferation. Additionally, the colony formation assay, flow cytometry analysis and wound healing displayed that Yangzheng Mixture and a combination of four components could inhibit colony formation, arrest the cell cycle and impair cell migration of tumor cells, including HCT-116, MHCC-97L, MCF-7 and NCI-H1299. In summary, our study highlighted the plausible application of Yangzheng Mixture as a potential adjuvant treatment for tumors. Furthermore, it identified effective anti-tumor components and provided evidences for the further clinical application of Yangzheng Mixture.

STING activation in macrophages by vanillic acid exhibits antineoplastic potential.

The host stimulator of interferon genes (STING) signaling pathway is a major innate immune sensing pathway, and the stimulation of this pathway within antigen-presenting cells shows promise in targeting immune-suppressed tumors. Macrophages resident in tumors exhibit anti-inflammatory properties and enhance tumor growth and development. Polarizing such macrophages towards a pro-inflammatory phenotype is an effective strategy for tumor suppression. In the present study, we observed that the STING pathway was inactivated in breast and lung carcinomas, and a positive correlation existed between STING and macrophage markers in these tumors. We found that vanillic acid (VA) could stimulate the STING/TBK1/IRF3 pathway. VA mediated the production of type I IFN and promoted macrophage polarization into the M1 phenotype; this activity was dependent on STING activation. A direct-contact co-culture model and a transwell co-culture model revealed that macrophages with VA-induced STING activation exhibited anti-proliferative effects on SKBR3 and H1299 cells, although a STING antagonist and M2 macrophage-related cytokines alleviated this anti-proliferative effect. Further investigation indicated that phagocytosis and apoptosis-inducing effects were the major mediators of the anti-tumor effect of VA-treated macrophages. Mechanistically, VA promoted the polarization of macrophages to a M1 phenotype via IL-6R/JAK signaling, resulting in enhanced phagocytosis and apoptosis-induction effects. Additionally, STING activation-induced IFNß production also participated in the apoptosis mediated by VA-treated macrophage in SKBR3 and H1299 cells. Mouse models with 4 T1 tumors confirmed the anti-tumor properties of VA in vivo and revealed the infiltration of VA-induced cytotoxic T cells into the tumors. These data suggest that VA is an effective agonist of STING and provides a new perspective for cancer immunotherapy.

Vandetanib drives growth arrest and promotes sensitivity to imatinib in chronic myeloid leukemia by targeting ephrin type-B receptor 4.

The oncogenic role of ephrin type-B receptor 4 (EPHB4) has been reported in many types of tumors, including chronic myeloid leukemia (CML). Here, we found that CML patients have a higher EPHB4 expression level than healthy subjects. EPHB4 knockdown inhibited growth of K562 cells (a human immortalized myelogenous leukemia cell line). In addition, transient transfection of EPHB4 siRNA led to sensitization to imatinib. These growth defects could be fully rescued by EPHB4 transfection. To identify an EPHB4-specific inhibitor with the potential of rapid translation into the clinic, a pool of clinical compounds was screened and vandetanib was found to be most sensitive to K562 cells, which express a high level of EPHB4. Vandetanib mainly acts on the intracellular tyrosine kinase domain and interacts stably with a hydrophobic pocket. Furthermore, vandetanib downregulated EPHB4 protein via the ubiquitin-proteasome pathway and inhibited PI3K/AKT and MAPK/ERK signaling pathways in K562 cells. Vandetanib alone significantly inhibited tumor growth in a K562 xenograft model. Furthermore, the combination of vandetanib and imatinib exhibited enhanced and synergistic growth inhibition against imatinib-resistant K562 cells in vitro and in vivo. These findings suggest that vandetanib drives growth arrest and overcomes the resistance to imatinib in CML via targeting EPHB4.

Shuanghua decoction exerts anticancer activity by activating NLRP3 inflammasome via ROS and inhibiting NF-κB signaling in hepatocellular carcinoma cells.

BACKGROUND: Hepatocellular carcinoma (HCC) is a major subtype of liver cancer, with a high mortality rate, and close relation to chronic hepatitis. The components of the NLRP3 inflammasome are poorly expressed or even lost in HCC. Downregulation of the NLRP3 inflammasome expression significantly affects the clinical stages and pathological grade of HCC. According to previous research, Shuanghua decoction (SHD), a traditional folk prescription, has an inhibitory effect on nasopharyngeal cancer. PURPOSE: This study aimed to reveal the therapeutic potential of the traditional folk recipe, SHD and its demolition recipe for HCC, and to explore the underlying mechanism. METHODS: The effect of SHD and its demolition recipe on HCC cell biological behaviors was assessed using the MTT assay, colony formation, LDH release assay, KFluor-Edu staining, annexin V-FITC/PI staining assay, Hoechst staining, wound-healing assay, transwell assay, reactive oxygen species (ROS) release assay, HPLC, nude mice model, HE staining, IHC, western blot, and immunofluorescence staining in vitro and in vivo. RESULTS: SHD was found to inhibit HCC, and Oldenlandia and OP (Oldenlandia: Prunella spike = 2.5:1) were identified as the main ingredients that inhibited the proliferation and migration of HCC cells via the activation of the ROS-mediated NLRP3 inflammasome and inhibition of the NF-κB signaling pathway in vitro and in vivo. CONCLUSION: Overall, Chinese medicine theory and pharmacology research revealed that SHD, Oldenlandia and OP may be promising traditional Chinese medicine for the treatment of HCC.

TAD1822-7 induces ROS-mediated apoptosis of HER2 positive breast cancer by decreasing E-cadherin in an EphB4 dependent manner.

HER2-positive breast cancer (HER2-BC) shows the over-expression of tyrosine kinase receptor EphB4 associated with poor disease prognosis. E-cadherin is found as a survival factor in multiple models of breast cancer by suppressing reactive oxygen-mediated apoptosis. This study confirmed that both HER2 and EphB4 are positively correlated with E-cadherin in HER2-BC. Inhibition of HER2 or EphB4 is discovered to induce ROS-dependent apoptosis by decreasing E-cadherin expression in SKBR3 and MDA-MB-453 cells. TAD1822-7 (TAD), a novel biphenyl urea taspine derivative, exhibits good growth inhibition, apoptosis induction and ROS accumulation effects on SKBR3 and MDA-MB-453 cells. Mechanistic investigation revealed that TAD blockades both EphB4 positive signal transduction and activation of HER2 signal transduction, thereby suppressing E-cadherin/TGF-ß/p-Smad2/3 signaling axis to elicit ROS-dependent endogenous mitochondrial apoptosis. Together, these findings not only provide a new approach for HER2-BC therapy but also increase our understanding of the regulating effect of E-cadherin by HER2 and EphB4 in ROS-mediated apoptosis.

Homoharringtonine suppresses tumor proliferation and migration by regulating EphB4-mediated ß-catenin loss in hepatocellular carcinoma.

Overexpressed EphB4 conduce to tumor development and is regarded as a potential anticancer target. Homoharringtonine (HHT) has been approved for hematologic malignancies treatment, but its effect on hepatocellular carcinoma (HCC) has not been studied. This study elucidated HHT could restrain the proliferation and migration of HCC via an EphB4/ß-catenin-dependent manner. We found that the antiproliferative activity of HHT in HCC cells and tumor xenograft was closely related to EphB4 expression. In HepG2, Hep3B and SMMC-7721 cells, EphB4 overexpression or EphrinB2 Fc stimulation augmented HHT-induced inhibitory effect on cell growth and migration ability, and such effect was abrogated when EphB4 was knocked down. The similar growth inhibitory effect of HHT was observed in SMMC-7721 and EphB4+/SMMC-7721 cells xenograft in vivo. Preliminary mechanistic investigation indicated that HHT directly bound to EphB4 and suppressed its expression. Data obtained from HCC patients revealed increased ß-catenin expression and a positive correlation between EphB4 expression and ß-catenin levels. HHT-induced EphB4 suppression promoted the phosphorylation and loss of ß-catenin, which triggered regulation of ß-catenin downstream signaling related to migration, resulting in the reversion of EMT in TGF-ß-induced HepG2 cells. Collectively, this study provided a groundwork for HHT as an effective antitumor agent for HCC in an EphB4/ß-catenin-dependent manner.

Sanguinarine suppresses migration and metastasis in colorectal carcinoma associated with the inversion of EMT through the Wnt/ß-catenin signaling.

BACKGROUND: Unresectable lung or liver organ metastases of colorectal carcinoma (CRC) remain a major obstacle in clinical therapeutics. Epithelial to mesenchymal transition (EMT), a major cause of highly frequent metastasis in tumor, can be promoted by the Wnt/ß-catenin pathway that is aberrantly activated in approximately 90% of CRC. This research aimed to elucidate the antimetastatic potential of sanguinarine (SG) in CRC and the underlying molecular mechanism. METHODS: The in vitro anticancer effect of SG was determined via cell viability experiment and colony formation assay. Xenograft model of nude mice was used to confirm the antitumor effect of SG in vivo. The antimetastatic potential of SG was investigated by the metastasis model of nude mice, hematoxylin and eosin (H&E) staining, migration assay, and wound-healing analysis. Immunoblotting analysis, immunofluorescence staining, and immunohistochemistry assay were conducted to elucidate the molecular mechanism. RESULTS: In this study, we reported that SG has a selective inhibitory effect on LoVo cells with metastatic characteristics. Furthermore, our results showed attenuation in the migration and metastatic ability of SG-treated LoVo cells and also decreased metastatic nodules of liver and lung in mice metastasis model. This was also confirmed at the molecular level via H&E staining. Further study revealed that SG had negative impacts on the Wnt/ß-catenin pathway and EMT markers in LoVo cells both in vitro and in vivo. CONCLUSIONS: Taken together, the antimetastatic potential of SG attributed to the suppression of the Wnt/ß-catenin signaling, which further prevented EMT progression. SG may be of value in a potential therapy for the management of metastasis CRC.

Cantharidin treatment inhibits hepatocellular carcinoma development by regulating the JAK2/STAT3 and PI3K/Akt pathways in an EphB4-dependent manner.

Hepatocellular carcinoma (HCC) is a lethal malignancy with limited treatment options. The tyrosine kinase receptor EphB4 promotes oncogenesis and tumor development and progression. Its inhibition is regarded as an effective strategy for the treatment of solid tumors. In the present study, we identified cantharidin as a novel EphB4 inhibitor for HCC treatment and evaluated the underlying molecular pharmacological mechanisms of action. We observed increased expression levels of EphB4 in HCC patients and a positive correlation between EphB4 and p-JAK2 levels in HCC patient samples. Knockdown of EphB4 using small interfering RNA decreased the expression levels of p-JAK2 and p-STAT3 in HCC cells, suggesting JAK2/STAT3 being a novel downstream signaling target of EphB4. Cell viability experiments revealed that the anti-cancer effect of cantharidin was positively correlated with EphB4 expression levels in HCC cell lines. We confirmed the potent antiproliferative activity of cantharidin on HepG2 cells with high expression of EphB4 and tumor xenograft. Molecular docking assay, immunoblotting assay and quantitative reverse transcription PCR assay indicated that cantharidin bound to EphB4, and thereby resulted in EphB4 suppression at mRNA and protein levels. Hep3B and SMMC-7721 cells were with low expression of EphB4. In EphB4-/HepG2, EphB4+/HepG2, and EphB4+/Hep3B cells, EphB4 knockdown alleviated the cantharidin-induced decrease in cell viability and colony formation ability and increase in apoptosis in HepG2 cells, while its overexpression exacerbated these effects in Hep3B cells and increased the apoptosis of HepG2 cells. In nude mouse models, cantharidin suppressed tumor growth more effectively in EphB4+/SMMC-7721 xenografts than in wild-type SMMC-7721 xenografts. Underlying mechanistic study showed that by targeting EphB4, cantharidin blocked a novel target, the downstream JAK2/STAT3 pathway, and the previously known target, the PI3K/Akt signaling, resulting in intrinsic apoptosis. These results indicated that cantharidin may be a potential candidate for HCC treatment by regulating the EphB4 signaling pathway.

TPD7 inhibits the growth of cutaneous T cell lymphoma H9 cell through regulating IL-2R signalling pathway.

IL-2R pathway is a key regulator in the development of immune cells and has emerged as a promising drug target in cancer treatment, but there is a scarcity of related inhibitors. TPD7 is a novel biphenyl urea taspine derivate, which has been shown anti-cancer effect. Here, we demonstrated the anti-cancer activity of TPD7 in cutaneous T cell lymphoma and investigated the underlying mechanism of TPD7 through IL-2R signalling. The inhibitory effect of TPD7 on cell viability exhibited a strong correlation with the expression level of IL-2R, and cutaneous T cell lymphoma H9 and HUT78 cells were most sensitive to TPD7. TPD7 was nicely bound to IL-2R and down-regulated the mRNA and protein levels of IL-2R. Furthermore, TPD7 suppressed the downstream cascades of IL-2R including JAK/STAT, PI3K/AKT/mTOR and PLCγ/Raf/MAPK signalling, resulting in Bcl-2 mitochondrial apoptosis pathway and cell cycle proteins CDK/Cyclins regulation. And, these were verified by flow cytometry analysis that TPD7 facilitated cell apoptosis in H9 cells via mitochondrial pathway and impeded cell cycle progression at G2/M phase. TPD7 is a novel anti-cancer agent and may be a potential candidate for cutaneous T cell lymphoma treatment by regulating IL-2R signalling pathway.

Homoharringtonine suppresses LoVo cell growth by inhibiting EphB4 and the PI3K/AKT and MAPK/EKR1/2 signaling pathways.

Colorectal cancer (CRC) remains one of the most common gastrointestinal tumors, characterized by a poor survival rate. Effects of single use of homoharringtonine (HHT), approved for the treatment of acute myelocytic leukemia (AML) and chronic myeloid leukemia (CML), on CRC, are unknown. According to the TCGA database, EphB4 is aberrantly overexpressed in CRC patients. Therefore, the purpose of this study was to investigate the inhibitory effect of HHT on CRC and its underlying mechanism. HHT significantly suppressed LoVo cell growth in vitro and in vivo, and induced apoptosis and cell cycle arrest at the S phase. Mechanistic investigation using western blotting revealed that HHT suppressed EphB4, and this suppression was augmented by both HHT and NVP-BHG712 co-administration and EphB4 overexpression, indicating that HHT targets EphB4 to suppress LoVo cell growth. HHT inhibited EphB4 downstream pathways such as PI3K/AKT and MAPK/EKR1/2, resulting in the regulation of cell cycle-related molecules (cyclinA2 and CDC2), and the molecules in the Bcl-2 mitochondrial apoptosis pathway including Bcl-2, Mcl-1, Bax, Bad, caspase-3, caspase-7, and caspase-9. HHT may therefore be a promising EphB4 inhibitor with great potential for CRC treatment.