Liang Shun Wang

Trifluoperazine, an Antipsychotic Agent, Inhibits Cancer Stem Cell Growth and Overcomes Drug Resistance of Lung Cancer

RATIONALE Cancer stem cell (CSC) theory has drawn much attention, with evidence supporting the contribution of stem cells to tumor initiation, relapse, and therapy resistance. OBJECTIVES To screen drugs that target CSCs to improve the current treatment outcome and overcome drug resistance in patients with lung cancer. METHODS We used publicly available embryonic stem cell and CSC-associated gene signatures to query the Connectivity Map for potential drugs that can, at least in part, reverse the gene expression profile of CSCs. High scores were noted for several phenothiazine-like antipsychotic drugs, including trifluoperazine. We then treated lung CSCs with different EGFR mutation status with trifluoperazine to examine its anti-CSC properties. Lung CSCs resistant to epidermal growth factor receptor-tyrosine kinase inhibitor or cisplatin were treated with trifluoperazine plus gefitinib or trifluoperazine plus cisplatin. Animal models were used for in vivo validation of the anti-CSC effect and synergistic effect of trifluoperazine with gefitinib. MEASUREMENTS AND MAIN RESULTS We demonstrated that trifluoperazine inhibited CSC tumor spheroid formation and down-regulated the expression of CSC markers (CD44/CD133). Trifluoperazine inhibited Wnt/β-catenin signaling in gefitinib-resistant lung cancer spheroids. The combination of trifluoperazine with either gefitinib or cisplatin overcame drug resistance in lung CSCs. Trifluoperazine inhibited the tumor growth and enhanced the inhibitory activity of gefitinib in lung cancer metastatic and orthotopic CSC animal models. CONCLUSIONS Using in silico drug screening by Connectivity Map followed by empirical validations, we repurposed an existing phenothiazine-like antipsychotic drug, trifluoperazine, as a potential anti-CSC agent that could overcome epidermal growth factor receptor-tyrosine kinase inhibitor and chemotherapy resistance.

Pterostilbene, a bioactive component of blueberries, suppresses the generation of breast cancer stem cells within tumor microenvironment and metastasis via modulating NF‐κB/microRNA 448 circuit

SCOPE Tumor-associated macrophages (TAMs) have been shown to promote metastasis and malignancy. Pterostilbene, a natural stilbene isolated from blueberries, has been suggested for anti-cancer effects. Here, we explored the potential cancer stem cells (CSCs)/TAM modulating effects of pterostilbene in breast cancer. METHODS AND RESULTS Using flowcytometric and Boyden chamber assay, we showed MCF7 and MDA-MB-231 cells cocultured with M2 TAMs exhibited increased percentage of CD44(+) /CD24(-) CSC population and migratory/invasive abilities. RT-PCR results showed that CD44(+) /CD24(-) cells expressed an increased level of HIF-1α, β-catenin, Twist1, and NF-κB and enhanced tumor sphere forming ability. Additionally, pterostilbene treatment dose dependently overcame M2 TAM-induced enrichment of CSCs and metastatic potential of breast cancer cells. Mechanistically, pterostilbene suppressed NFκB, Twist1, vimentin, and increased E-cadherin expression. Using siRNA technique, we demonstrated that pterostilbene-mediated NFκB downregulation was correlated to an increased amount of microRNA 448. Finally, pterostilbene-mediated suppression in tumorigenesis and metastasis was validated by noninvasive bioluminescence in mice bearing M2 TAM cocultured MDA-MB-231 tumor. CONCLUSION Pterostilbene effectively suppresses the generation of CSCs and metastatic potential under the influence of M2 TAMs via modulating EMT associated signaling pathways, specifically NF-κB/miR488 circuit. Thus, pterostilbene could be an ideal anti-CSC agent in clinical settings.

A sesquiterpene lactone antrocin from Antrodia camphorata negatively modulates JAK2/STAT3 signaling via microRNA let-7c and induces apoptosis in lung cancer cells.

Lung cancer is the leading cause of cancer deaths worldwide and current therapies fail to treat this disease in majority of cases. Antrodia camphorata is a medicinal mushroom being widely used as food dietary supplement for cancer prevention. The sesquiterpene lactone antrocin is the most potent among >100 secondary metabolites isolated from A. camphorata. However, the molecular mechanisms of antrocin-mediated anticancer effects remain unclear. In this study, we found that antrocin inhibited cell proliferation in two non-small-cell lung cancer cells, namely H441 (wild-type epidermal growth factor receptor, IC50 = 0.75 μM) and H1975 (gefitnib-resistant mutant T790M, IC50 = 0.83 μM). Antrocin dose dependently suppressed colony formation and induced apoptosis as evidenced by activated caspase-3 and increased Bax/Bcl2 ratio. Gene profiling studies indicated that antrocin downregulated Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway. We further demonstrated that antrocin suppressed both constitutively activated and interleukin 6-induced STAT3 phosphorylation and its subsequent nuclear translocation. Such inhibition is found to be achieved through the suppression of JAK2 and interaction between STAT3 and extracellular signal-regulated kinase. Additionally, antrocin increased microRNA let-7c expression and suppressed STAT signaling. The combination of antrocin and JAK2/STAT3 gene silencing significantly increased apoptosis in H441 cells. Such dual interruption of JAK2 and STAT3 pathways also induced downregulation of antiapoptotic protein mcl-1 and increased caspase-3 expression. In vivo intraperitoneal administration of antrocin significantly suppressed the growth of lung cancer tumor xenografts. Our results indicate that antrocin may be a potential therapeutic agent for human lung cancer cells through constitutive inhibition of JAK2/STAT3 pathway.

Sulforaphane potentiates the efficacy of imatinib against chronic leukemia cancer stem cells through enhanced abrogation of Wnt/β-catenin function

Sulforaphane (SFN) has been indicated for the prevention and suppression of tumorigenesis in solid tumors. Herein, we evaluated SFNs effects on imatinib (IM)-resistant leukemia stem cells (LSCs). CD34(+)/CD38(-) and CD34(+)/CD38(+) LSCs were isolated from KU812 cell line flowcytometrically. Isolated LSCs showed high expression of Oct4, CD133, β-catenin, and Sox2 and IM resistance. Differentially, CD34(+)/CD38(-) LSCs demonstrated higher BCR-ABL and β-catenin expression and imatinib (IM) resistance than CD34(+)/CD38(+) counterparts. IM and SFN combined treatment sensitized CD34(+)/CD38(-) LSCs and induced apoptosis, shown by increased caspase 3, PARP, and Bax while decreased Bcl-2 expression. Additionally, the combined treatment reduced BCR-ABL and β-catenin and MDR-1 protein expression. Mechanistically, IM and SFN combined treatment resensitized LSCs by inducing intracellular reactive oxygen species (ROS). Importantly, β-catenin-silenced LSCs exhibited reduced glutathione S-transferase pi 1 (GSTP1) expression and intracellular GSH level, which led to increased sensitivity toward IM and SFN. We demonstrated that IM and SFN combined treatment effectively eliminated CD34(+)/CD38(-) LSCs. Since SFN has been shown well tolerated in both animals and human, this regimen could be considered for clinical trials.

Preclinical evaluation of destruxin B as a novel Wnt signaling target suppressing proliferation and metastasis of colorectal cancer using non-invasive bioluminescence imaging

In continuation to our studies toward the identification of direct anti-cancer targets, here we showed that destruxin B (DB) from Metarhizium anisopliae suppressed the proliferation and induced cell cycle arrest in human colorectal cancer (CRC) HT29, SW480 and HCT116 cells. Additionally, DB induced apoptosis in HT29 cells by decreased expression level of anti-apoptotic proteins Bcl-2 and Bcl-xL while increased pro-apoptotic Bax. On the other hand, DB attenuated Wnt-signaling by downregulation of β-catenin, Tcf4 and β-catenin/Tcf4 transcriptional activity, concomitantly with decreased expression of β-catenin target genes cyclin D1, c-myc and survivin. Furthermore, DB affected the migratory and invasive ability of HT29 cells through suppressed MMPs-2 and -9 enzymatic activities. We also found that DB targeted the MAPK and/or PI3K/Akt pathway by reduced expression of Akt, IKK-α, JNK, NF-κB, c-Jun and c-Fos while increased that of IκBα. Finally, we demonstrated that DB inhibited tumorigenesis in HT29 xenograft mice using non-invasive bioluminescence technique. Consistently, tumor samples from DB-treated mice demonstrated suppressed expression of β-catenin, cyclin D1, survivin, and endothelial marker CD31 while increased caspase-3 expression. Collectively, our data supports DB as an inhibitor of Wnt/β-catenin/Tcf signaling pathway that may be beneficial in the CRC management.

Aberrant KDM5B expression promotes aggressive breast cancer through MALAT1 overexpression and downregulation of hsa-miR-448

AbstractBackgroundTriple negative breast cancers (TNBC) possess cell dedifferentiation characteristics, carry out activities connate to those of cancer stem cells (CSCs) and are associated with increased metastasis, as well as, poor clinical prognosis. The regulatory mechanism of this highly malignant phenotype is still poorly characterized. Accruing evidence support the role of non-coding RNAs (ncRNAs) as potent regulators of CSC and metastatic gene expression, with their dysregulation implicated in tumorigenesis and disease progression.MethodsIn this study, we investigated TNBC metastasis, metastasis-associated genes and potential inhibitory mechanisms using bioinformatics, tissue microarray analyses, immunoblotting, polymerase chain reaction, loss and gain of gene function assays and comparative analyses of data obtained.ResultsCompared with other breast cancer types, the highly metastatic MDA-MB-231 cells concurrently exhibited increased expression levels of Lysine-specific demethylase 5B protein (KDM5B) and long non-coding RNA (lncRNA), MALAT1, suggesting their functional association. KDM5B-silencing in the TNBC cells correlated with the upregulation of hsa-miR-448 and led to suppression of MALAT1 expression with decreased migration, invasion and clonogenic capacity in vitro, as well as, poor survival in vivo. This projects MALAT1 as a mediator of KDM5B oncogenic potential and highlights the critical role of this microRNA, lncRNA and histone demethylase in cancer cell motility and metastatic colonization. Increased expression of KDM5B correlating with disease progression and poor clinical outcome in breast cancer was reversed by hsa-miR-448.ConclusionsOur findings demonstrate the critical role of KDM5B and its negative regulator hsa-miR-448 in TNBC metastasis and progression. Hsa-miR-448 disrupting KDM5B-MALAT1 signalling axis and associated activities in TNBC cells, projects it as a putative therapeutic factor for selective eradication of TNBC cells. Graphical abstractKDM5B, MALAT1 and hsa-miR-448 are active looped components of the epigenetic poculo mortis in aggressive breast cancer.

Pterostilbene inhibits triple-negative breast cancer metastasis via inducing microRNA-205 expression and negatively modulates epithelial-to-mesenchymal transition

Breast cancer is the leading cause of cancer-related deaths among females in economically developing countries. Greater than 95% of breast malignancies are of epithelial origin; the induction of epithelial-to-mesenchymal transition (EMT) has been shown to initiate the metastatic process in breast carcinoma and remains the key target for drug development. Here, we examine the anti-metastatic potential of pterostilbene in modulating EMT process in breast cancer cells both in vitro and in vivo. The differential invasive ability among MCF7, Hs578t and MDA-MB-231 breast cancer cell lines were closely correlated with the expression of EMT markers, determined by Western blots and Matrigel-coated transwells assay. Pterostilbene inhibited the migratory and invasive potential of triple-negative MDA-MB-231 and Hs578t cells, accompanied by the up-regulation of E-cadherin and down-regulation of Snail, Slug, vimentin and ZEB1. Mechanistic investigations revealed a significant up-regulation of miR-205, which resulted in the reduction of Src expression in pterostilbene-treated breast cancer cells. Importantly, pterostilbene suppressed tumor growth and metastasis in MDA-MB-231-bearing NOD/SCID mice by reducing Src/Fak signaling; this observation was consistent with the negative correlations between miR-205 and Src expression in both normal and malignant breast tissues. Our findings provide supports for the usage of pterostilbene as an inhibitor of EMT process and potential candidate for adjuvant therapy.

Ovatodiolide sensitizes aggressive breast cancer cells to doxorubicin, eliminates their cancer stem cell-like phenotype, and reduces doxorubicin-associated toxicity

Triple-negative breast cancer (TNBC) is chemotherapy-refractory and associated with poor clinical prognosis. Doxorubicin (Doxo), a class I anthracycline and first-line anticancer agent, effective against a wide spectrum of neoplasms including breast carcinoma, is associated with several cumulative dose-dependent adverse effects, including cardiomyopathy, typhilitis, and acute myelotoxicity. This study evaluated the usability of Ovatodiolide (Ova) in sensitizing TNBC cells to Doxo cytotoxicity, so as to reduce Doxo effective dose and consequently its adverse effects. TNBC cell lines MDA-MB-231 and HS578T were used. Pre-treatment of the TNBC cells with 10 µM Ova 24 h before Doxo administration increased the Doxo anticancer effect (IC50 1.4 µM) compared to simultaneous treatment with Doxo ( IC50 1.8 µM), or Doxo alone (IC50 9.2 µM). Intracellular accumulation of Doxo was lowest in Ova pre-treated cells at all Doxo concentrations, when compared with Doxo or simultaneously treated cells. In comparison to the Doxo-only group, cell cycle analysis of MDA-MB-231 cells treated concurrently with 2.5 µM Ova and 1.25 µM Doxo showed increased percentage of cells arrested at G0/G1; however, pre-treatment with the same concentration of Ova 24 h before Doxo showed greater tumor growth inhibition, with a 2.4-fold increased percentage of cells in G0/G1 arrest, greater Doxo-induced apoptosis, and significantly reduced intracellular Doxo accumulation. Additionally, Ova-sensitized TNBC cells also lost their cancer stem cell-like phenotype evidenced by significant dissolution, necrosis of formed mammospheres. Taken together, these findings indicate that Ova sensitizes TNBC cells to Doxo and potentiates doxorubicin-induced elimination of the TNBC cancer stem cell-like phenotype.

4-Acetylantroquinonol B inhibits colorectal cancer tumorigenesis and suppresses cancer stem-like phenotype.

4-Acetylantroquinonol B (4-AAQB), closely related to the better known antroquinonol, is a bioactive isolate of the mycelia of Antrodia camphorata, a Taiwanese mushroom with documented anti-inflammatory, hypoglycemic, vasorelaxative, and recently demonstrated, antiproliferative activity. Based on its traditional use, we hypothesized that 4-AAQB may play an active role in the suppression of cellular transformation, tumor aggression and progression, as well as chemoresistance in colorectal carcinoma (CRC). In this study, we investigated the antiproliferative role of 4-AAQB and its underlying molecular mechanism. We also compared its anticancer therapeutic potential with that of antroquinonol and the CRC combination chemotherapy of choice - folinic acid, fluorouracil and oxaliplatin (FOLFOX). Our results showed that 4-AAQB was most effective in inhibiting tumor proliferation, suppressing tumor growth and attenuating stemness-related chemoresistance. 4-AAQB negatively regulates vital oncogenic and stem cell maintenance signal transduction pathways, including the Lgr5/Wnt/β-catenin, JAK-STAT, and non-transmembrane receptor tyrosine kinase signaling pathways, as well as inducing a dose-dependent downregulation of ALDH and other stemness related factors. These results were validated in vivo, with animal studies showing 4-AAQB possessed comparable tumor-shrinking ability as FOLFOX and potentiates ability of the later to reduce tumor size. Thus, 4-AAQB, a novel small molecule, projects as a potent therapeutic agent for monotherapy or as a component of standard combination chemotherapy.

JARID1B expression plays a critical role in chemoresistance and stem cell-like phenotype of neuroblastoma cells

Neuroblastoma (NB) is a common neural crest-derived extracranial solid cancer in children. Among all childhood cancers, NB causes devastating loss of young lives as it accounts for 15% of childhood cancer mortality. Neuroblastoma, especially high-risk stage 4 NB with MYCN amplification has limited treatment options and associated with poor prognosis. This necessitates the need for novel effective therapeutic strategy. JARID1B, also known as KDM5B, is a histone lysine demethylase, identified as an oncogene in many cancer types. Clinical data obtained from freely-accessible databases show a negative correlation between JARID1B expression and survival rates. Here, we demonstrated for the first time the role of JARID1B in the enhancement of stem cell-like activities and drug resistance in NB cells. We showed that JARID1B may be overexpressed in either MYCN amplification (SK-N-BE(2)) or MYCN-non-amplified (SK-N-SH and SK-N-FI) cell lines. JARID1B expression was found enriched in tumor spheres of SK-N-BE(2) and SK-N-DZ. Moreover, SK-N-BE(2) spheroids were more resistant to chemotherapeutics as compared to parental cells. In addition, we demonstrated that JARID1B-silenced cells acquired a decreased propensity for tumor invasion and tumorsphere formation, but increased sensitivity to cisplatin treatment. Mechanistically, reduced JARID1B expression led to the downregulation of Notch/Jagged signaling. Collectively, we provided evidence that JARID1B via modulation of stemness-related signaling is a putative novel therapeutic target for treating malignant NB.