Metastatic Progression of Prostate Cancer Is Mediated by Autonomous Binding of Galectin-4-O-Glycan to Cancer Cells

Metastatic prostate cancer continues to pose a difficult therapeutic challenge. Prostate cancer progression is associated with aberrant O-glycosylation of cancer cell surface receptors, but the functional impact of such events is uncertain. Here we report spontaneous metastasis of human prostate cancer xenografts that express high levels of galectin-4 along with genetic signatures of EGFR-HER2 signaling and O-glycosylation. Galectin-4 expression in clinical specimens of prostate cancer correlated with poor patient survival. Galectin-4 binding to multiple receptor tyrosine kinases stimulated their autophosphorylation, activated expression of pERK, pAkt, fibronectin, and Twist1, and lowered expression of E-cadherin, thereby facilitating epithelial-mesenchymal transition, invasion, and metastasis. In vivo investigations established that galectin-4 expression enabled prostate cancer cells to repopulate tumors in orthotopic and heterotopic tissues. Notably, these effects of galectin-4 relied upon O-glycosylation mediated by C1GALT1, a galactosyltransferase implicated in other cancers. Parallel changes in galectin-4 and O-glycosylation triggered aberrant receptor signaling and more aggressive invasive character in prostate cancer cells, which through better survival in the circulation also contributed to the bulk cell progeny of distal tumors. Our findings establish galectin-4 and C1GALT1-mediated glycosylation in a signaling axis that is activated during prostate cancer progression, with implications for therapeutic targeting of advanced metastatic disease. Cancer Res; 76(19); 5756-67. ©2016 AACR.

Induction of IL-25 secretion from tumour-associated fibroblasts suppresses mammary tumour metastasis

Tumour-associated fibroblasts (TAFs), as a functionally supportive microenvironment, play an essential role in tumour progression. Here we investigate the role of IL-25, an endogenous anticancer factor secreted from TAFs, in suppression of mouse 4T1 mammary tumour metastasis. We show that a synthetic dihydrobenzofuran lignan (Q2-3), the dimerization product of plant caffeic acid methyl ester, suppresses 4T1 metastasis by increasing fibroblastic IL-25 activity. The secretion of IL-25 from treated human or mouse fibroblasts is enhanced in vitro, and this activity confers a strong suppressive effect on growth activity of test carcinoma cells. Subsequent in vivo experiments showed that the anti-metastatic effects of Q2-3 on 4T1 and human MDA-MD-231 tumour cells are additive when employed in combination with the clinically used drug, docetaxel. Altogether, our findings reveal that the release of IL-25 from TAFs may serve as a check point for control of mammary tumour metastasis and that phytochemical Q2-3 can efficiently promote such anticancer activities.

Interleukin-25 has been reported to have anticancer activity with very little effect on non-malignant cells. Here, the authors show that a synthetic phytochemical can be used to induce the secretion of Interleukin-25 from tumour associated fibroblasts resulting in impaired tumour metastasis.

Abstract B67: Matriptase is involved in COX-2 signaling-induced prostate cancer cell invasion

Chronic inflammation plays an important role in the early development and progression of cancer. Cyclooxygenases-2 (COX-2) is a key rate-limiting enzyme which regulates of inflammation-producing prostaglandins. Several studies have shown that COX-2 is found with overexpression in human cancers (colon, breast, lung, prostate cancers, etc), and implicated in cancer cell invasion. Moreover, high COX-2 expression has been correlated with prostate cancer metastasis. However, the molecular mechanism that COX-2 promotes prostate cancer cell invasion is still unclear. In this study, we established a PC-3 cell invasion progression model (parental and M2I2 PC-3 cells) and found out that several inflammation-associated proteins, COX-2, p-JNK and IL-1β were up-regulated in M2I2 PC-3 cells. Therefore, we purposed that if COX-2 signaling plays a role in prostate cancer cell invasion and the involvement of matriptase in COX-2 signaling-induced cancer cell invasion. The results showed that COX-2 inhibitors (celebrex and sulindac sulfide) could suppress prostate cancer PC3 cell invasion and inhibited matriptase expression and activation. A COX-2 product PGE2 could induce matriptase activation and prostate cancer cell invasion. COX-2 overexpression also could up-regulate matriptase and enhance the cancer cell invasion, while COX-2 silencing antagonized both matriptase activation and cell invasion. Thus, our results indicate that COX-2 signaling can promote prostate cancer cell invasion, at least in part via up-regulating matriptase.

Citation Format: Chun-Jung Ko, Ying-Chieh Lu, Pee-Fang Lai, Pei-Wen Hsiao, Ming-Shyue Lee. Matriptase is involved in COX-2 signaling-induced prostate cancer cell invasion. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Metastasis; 2015 Nov 30-Dec 3; Austin, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(7 Suppl):Abstract nr B67.

Induction of c-Cbl contributes to anti-cancer effects of HDAC inhibitor in lung cancer

Here we found loss of c-Cbl, an E3 ligase, expression in non-small cell lung cancer (NSCLC) compared with its adjacent normal tissue in patient specimens. HDAC inhibition by WJ or knockdown of HDAC 1, HDAC2, HDAC3 or HDAC6 all induced c-Cbl. Ectopic expression of c-Cbl induced decreased EGFR, inhibited growth in NSCLC cells. Knockdown of EGFR inhibited NSCLC growth. Mutation of EGFR at Y1045 decreased WJ-induced growth inhibition as well as in vivo anti-cancer effect and EGFR degradation mediated by WJ. Time-lapse confocal analysis showed co-localization of c-Cbl and EGFR after WJ treatment. Furthermore, WJ inhibited lung tumor growth through c-Cbl induction in orthotopic and tail vein injected models. C-Cbl up-regulation induced by HDACi is a potential strategy for NSCLC treatment.

A novel H6N1 virus-like particle vaccine induces long-lasting cross-clade antibody immunity against human and avian H6N1 viruses

Avian influenza A(H6N1) virus is one of the most common viruses isolated from migrating birds and domestic poultry in many countries. The first and only known case of human infection by H6N1 virus in the world was reported in Taiwan in 2013. This led to concern that H6N1 virus may cause a threat to public health. In this study, we engineered a recombinant H6N1 virus-like particle (VLP) and investigated its vaccine effectiveness compared to the traditional egg-based whole inactivated virus (WIV) vaccine. The H6N1-VLPs exhibited similar morphology and functional characteristics to influenza viruses. Prime-boost intramuscular immunization in mice with unadjuvanted H6N1-VLPs were highly immunogenic and induced long-lasting antibody immunity. The functional activity of the VLP-elicited IgG antibodies was proved by in vitro seroprotective hemagglutination inhibition and microneutralization titers against the homologous human H6N1 virus, as well as in vivo viral challenge analyses which showed H6N1-VLP immunization significantly reduced viral load in the lung, and protected against human H6N1 virus infection. Of particular note, the H6N1-VLPs but not the H6N1-WIVs were able to confer cross-reactive humoral immunity; antibodies induced by H6N1-VLP vaccine robustly inhibited the hemagglutination activities and in vitro replication of distantly-related heterologous avian H6N1 viruses. Furthermore, the H6N1-VLPs were found to elicit significantly greater anti-HA2 antibody responses in immunized mice than H6N1-WIVs. Collectively, we demonstrated for the first time a novel H6N1-VLP vaccine that effectively provides broadly protective immunity against both human and avian H6N1 viruses. These results, which uncover the underlying mechanisms for induction of wide-range immunity against influenza viruses, may be useful for future influenza vaccine development.

Development of single-chain variable fragments (scFv) against influenza virus targeting hemagglutinin subunit 2 (HA2)

Influenza A viruses (IAV) are widespread in birds and domestic poultry, occasionally causing severe epidemics in humans and posing health threats. Hence, the need to develop a strategy for prophylaxis or therapy, such as a broadly neutralizing antibody against IAV, is urgent. In this study, single-chain variable fragment (scFv) phage display technology was used to select scFv fragments recognizing influenza envelope proteins. The Tomlinson I and J scFv phage display libraries were screened against the recombinant HA2 protein (rHA2) for three rounds. Only the third-round elution sample of the Tomlinson J library showed high binding affinity to rHA2, from which three clones (3JA18, 3JA62, and 3JA78) were chosen for preparative-scale production as soluble antibody by E. coli. The clone 3JA18 was selected for further tests due to its broad affinity for influenza H1N1, H3N2 and H5N1. Simulations of the scFv 3JA18-HA trimer complex revealed that the complementarity-determining region of the variable heavy chain (VH-CDR2) bound the stem region of HA. Neutralization assays using a peptide derived from VH-CDR2 also supported the simulation model. Both the selected antibody and its derived peptide were shown to suppress infection with H5N1 and H1N1 viruses, but not H3N2 viruses. The results also suggested that the scFvs selected from rHA2 could have neutralizing activity by interfering with the function of the HA stem region during virus entry into target cells.

S P, Wei WC, Lin HT, Yin SY, Yang NS. Rapamycin Promotes Mouse 4T1 Tumor Metastasis that Can Be Reversed by a Dendritic Cell-Based Vaccine

Suppression of tumor metastasis is a key strategy for successful cancer interventions. Previous studies indicated that rapamycin (sirolimus) may promote tumor regression activity or enhance immune response against tumor targets. However, rapamycin also exhibits immunosuppressant effects and is hence used clinically as an organ transplantation drug. We hypothesized that the immunosuppressive activities of rapamycin might also negatively mediate host immunity, resulting in promotion of tumor metastasis. In this study, the effects of rapamycin and phytochemical shikonin were investigated in vitro and in vivo in a 4T1 mouse mammary tumor model through quantitative assessment of immunogenic cell death (ICD), autophagy, tumor growth and metastasis. Tumor-bearing mice were immunized with test vaccines to monitor their effect on tumor metastasis. We found that intraperitoneal (ip) administration of rapamycin after a tumor-resection surgery drastically increased the metastatic activity of 4T1 tumors. Possible correlation of this finding to human cancers was suggested by epidemiological analysis of data from Taiwan’s National Health Insurance Research Database (NHIRD). Since our previous studies showed that modified tumor cell lysate (TCL)-pulsed, dendritic cell (DC)-based cancer vaccines can effectively suppress metastasis in mouse tumor models, we assessed whether such vaccines may help offset this rapamycin-promoted metastasis. We observed that shikonin efficiently induced ICD of 4T1 cells in culture, and DC vaccines pulsed with shikonin-treated TCL (SK-TCL-DC) significantly suppressed rapamycin-enhanced metastasis and Treg cell expansion in test mice. In conclusion, rapamycin treatment in mice (and perhaps in humans) promotes metastasis and the effect may be offset by treatment with a DC-based cancer vaccine.

Shikonin-enhanced cell immunogenicity of tumor vaccine is mediated by the differential effects of DAMP components

BACKGROUND

The tumor cell lysate-pulsed, dendritic cell (DC)-based cancer vaccine approaches are being actively evaluated for application to cancer immunotherapy, hopefully at a personalized medicine base. There is apparently an emerging technical problem however, the lack of highly efficacious potency in activation of patient's DCs for T-cell priming and the associated process for presenting tumor immunogenicity.

METHODS

One strategy to address this is to consider the manipulation of the tumor immunogenic cells death (ICD) complex ex-vivo for maximal activation of DC efficacy. In our previous study we showed that phytochemical shikonin (SK) can drastically enhance ICD activity in mouse tumor cells treated ex-vivo, and the resultant tumor cell lysate (TCL) can effectively augment such SK-TCL pulsed DC vaccine activity in vivo in anti-tumor activities. In this study, we investigated the specifics and the multi-functional effects of various damaged associated molecular pattern (DAMP) components of the ICD complex for their participation, roles and potential cross talks in activating DCs, as measured by five different functional assays.

RESULTS

Among three DAMPs tested, HSP70 and CRT mediate a key role in SK-TCL-induced DC immunity for both CD4(+) and CD8(+) T cell proliferations in vitro. HSP70 is the most important component, followed by CRT, then HMGB1 in facilitating DC immunity on suppressing metastasis of mouse 4 T1 mammary tumors and prolonging survival in test mice. Only HSP70, but not CRT or HMGB1, is effective for the suppression of both granulocytic and monocytic MDSC populations in vivo. Both HSP70 and HMGB1, but not CRT, are essential in activating the expression of three key ICD molecules-associated receptors on test DCs. Each of the three test ICD proteins can exhibit a distinguishable pattern in stimulating the expression of four key chemokines in test DCs.

CONCLUSION

Our findings on the differential roles or effect of various ICD components in activating vaccinated DCs may help formulate new strategies for future cancer vaccine designs.

Inactivated Enterovirus 71 Vaccine Produced by 200-L Scale Serum-Free Microcarrier Bioreactor System Provides Cross-Protective Efficacy in Human SCARB2 Transgenic Mouse

Epidemics and outbreaks caused by infections of several subgenotypes of EV71 and other serotypes of coxsackie A viruses have raised serious public health concerns in the Asia-Pacific region. These concerns highlight the urgent need to develop a scalable manufacturing platform for producing an effective and sufficient quantity of vaccines against deadly enteroviruses. In this report, we present a platform for the large-scale production of a vaccine based on the inactivated EV71(E59-B4) virus. The viruses were produced in Vero cells in a 200 L bioreactor with serum-free medium, and the viral titer reached 10(7) TCID50/mL 10 days after infection when using an MOI of 10(-4). The EV71 virus particles were harvested and purified by sucrose density gradient centrifugation. Fractions containing viral particles were pooled based on ELISA and SDS-PAGE. TEM was used to characterize the morphologies of the viral particles. To evaluate the cross-protective efficacy of the EV71 vaccine, the pooled antigens were combined with squalene-based adjuvant (AddaVAX) or aluminum phosphate (AlPO4) and tested in human SCARB2 transgenic (Tg) mice. The Tg mice immunized with either the AddaVAX- or AlPO4-adjuvanted EV71 vaccine were fully protected from challenges by the subgenotype C2 and C4 viruses, and surviving animals did not show any degree of neurological paralysis symptoms or muscle damage. Vaccine treatments significantly reduced virus antigen presented in the central nervous system of Tg mice and alleviated the virus-associated inflammatory response. These results strongly suggest that this preparation results in an efficacious vaccine and that the microcarrier/bioreactor platform offers a superior alternative to the previously described roller-bottle system.

Pharmacologic down-regulation of EZH2 suppresses bladder cancer in vitro and in vivo

The polycomb group gene, EZH2, is highly expressed in advanced bladder cancer. Here we demonstrated that down-regulation of EZH2 in tumor tissues after neo-adjuvant chemotherapy correlated with good therapeutic response in advanced bladder cancer. We next developed a small molecule, NSC745885, derived from natural anthraquinone emodin, which down-regulated EZH2 via proteasome-mediated degradation. NSC745885 showed potent selective toxicity against multiple cancer cell lines but not normal cells. NSC745885 treatment overcame multiple-drug resistance and inhibited growth of resistant cancer cells. Over-expression of EZH2 in cancer cells attenuated effects of NSC745885, suggesting that down-regulation of EZH2 was responsible for growth inhibition of NSC745885. NSC745885 also suppressed tumor growth and down-regulated EZH2 in vivo. These results indicate that NSC7455889 suppresses bladder cancer by targeting EZH2.

Novel Cancer Therapeutics with Allosteric Modulation of the Mitochondrial C-Raf-DAPK Complex by Raf Inhibitor Combination Therapy

Mitochondria are the powerhouses of cells. Mitochondrial C-Raf is a potential cancer therapeutic target, as it regulates mitochondrial function and is localized to the mitochondria by its N-terminal domain. However, Raf inhibitor monotherapy can induce S338 phosphorylation of C-Raf (pC-Raf(S338)) and impede therapy. This study identified the interaction of C-Raf with S308 phosphorylated DAPK (pDAPK(S308)), which together became colocalized in the mitochondria to facilitate mitochondrial remodeling. Combined use of the Raf inhibitors sorafenib and GW5074 had synergistic anticancer effects in vitro and in vivo, but targeted mitochondrial function, rather than the canonical Raf signaling pathway. C-Raf depletion in knockout MEF(C-Raf-/-) or siRNA knockdown ACHN renal cancer cells abrogated the cytotoxicity of combination therapy. Crystal structure simulation showed that GW5074 bound to C-Raf and induced a C-Raf conformational change that enhanced sorafenib-binding affinity. In the presence of pDAPK(S308), this drug-target interaction compromised the mitochondrial targeting effect of the N-terminal domain of C-Raf, which induced two-hit damages to cancer cells. First, combination therapy facilitated pC-Raf(S338) and pDAPK(S308) translocation from mitochondria to cytoplasm, leading to mitochondrial dysfunction and reactive oxygen species (ROS) generation. Second, ROS facilitated PP2A-mediated dephosphorylation of pDAPK(S308) to DAPK. PP2A then dissociated from the C-Raf-DAPK complex and induced profound cancer cell death. Increased pDAPK(S308) modification was also observed in renal cancer tissues, which correlated with poor disease-free survival and poor overall survival in renal cancer patients. Besides mediating the anticancer effect, pDAPK(S308) may serve as a predictive biomarker for Raf inhibitors combination therapy, suggesting an ideal preclinical model that is worthy of clinical translation.

Integrative approach to analyze biodiversity and anti-inflammatory bioactivity of Wedelia medicinal plants

For the development of "medical foods" and/or botanical drugs as defined USA FDA, clear and systemic characterizations of the taxonomy, index phytochemical components, and the functional or medicinal bioactivities of the reputed or candidate medicinal plant are needed. In this study, we used an integrative approach, including macroscopic and microscopic examination, marker gene analysis, and chemical fingerprinting, to authenticate and validate various species/varieties of Wedelia, a reputed medicinal plant that grows naturally and commonly used in Asian countries. The anti-inflammatory bioactivities of Wedelia extracts were then evaluated in a DSS-induced murine colitis model. Different species/varieties of Wedelia exhibited distinguishable morphology and histological structures. Analysis of the ribosomal DNA internal transcribed spacer (ITS) region revealed significant differences among these plants. Chemical profiling of test Wedelia species demonstrated candidate index compounds and distinguishable secondary metabolites, such as caffeic acid derivatives, which may serve as phytochemical markers or index for quality control and identification of specific Wedelia species. In assessing their effect on treating DSS induced-murine colitis, we observed that only the phytoextract from W. chinensis species exhibited significant anti-inflammatory bioactivity on DSS-induced murine colitis among the various Wedelia species commonly found in Taiwan. Our results provide a translational research approach that may serve as a useful reference platform for biotechnological applications of traditional phytomedicines. Our findings indicate that specific Wedelia species warrant further investigation for potential treatment of human inflammatory bowel disease.

Androgen-Induced TMPRSS2 Activates Matriptase and Promotes Extracellular Matrix Degradation, Prostate Cancer Cell Invasion, Tumor Growth, and Metastasis

Dysregulation of androgen signaling and pericellular proteolysis is necessary for prostate cancer progression, but the links between them are still obscure. In this study, we show how the membrane-anchored serine protease TMPRSS2 stimulates a proteolytic cascade that mediates androgen-induced prostate cancer cell invasion, tumor growth, and metastasis. We found that matriptase serves as a substrate for TMPRSS2 in mediating this proinvasive action of androgens in prostate cancer. Further, we determined that higher levels of TMPRSS2 expression correlate with higher levels of matriptase activation in prostate cancer tissues. Lastly, we found that the ability of TMPRSS2 to promote prostate cancer tumor growth and metastasis was associated with increased matriptase activation and enhanced degradation of extracellular matrix nidogen-1 and laminin β1 in tumor xenografts. In summary, our results establish that TMPRSS2 promotes the growth, invasion, and metastasis of prostate cancer cells via matriptase activation and extracellular matrix disruption, with implications to target these two proteases as a strategy to treat prostate cancer.

Development of a standardized and effect-optimized herbal extract of Wedelia chinensis for prostate cancer

Herbal medicine is a popular complementary or alternative treatment for prostate cancer. Wedelia chinensis has at least three active compounds, wedelolactone, luteolin, and apigenin synergistically inhibiting prostate cancer cell growth in vitro. Here, we report a systematic study to develop a standardized and effect-optimized herbal extract, designated as W. chinensis extract (WCE) to facilitate its future scientific validation and clinical use. Ethanolic extract of dried W. chinensis plant was further condensed, acid hydrolyzed, and enriched with preparative chromatography. The chemical compositions of multiple batches of the standardized preparation WCE were quantified by LC/MS/MS, and biological activities were analyzed by in vitro and in vivo assays. Furthermore, the pharmacokinetics of the holistic WCE were compared with the combination of the equivalent principal active compounds through oral administration. The results indicated that quantitative chemical assay and PSA (prostate-specific antigen)-reporter assay together are suitable to measure the quality and efficacy of a standardized Wedelia extract on a xenograft tumor model. The presence of minor concomitant compounds in WCE prolonged the systemic exposure to the active compounds, thus augmented the anti-tumor efficacy of WCE. In conclusion, a combination of LC/MS/MS and PSA reporter assay is suitable to qualify a standardized preparation of WCE. Furthermore, the pharmacokinetics and oral bioavailability of active compounds demonstrate that holistic WCE exerted additional pharmacological synergy beyond the multi-targeted therapeutic effects caused by more than one active compound. WCE merits a higher priority to be studied for use in prostate cancer treatment.

Abstract B85: High malignant prostate cancer cells developed enhanced tumor-initiating/metastatasis-initiating activity and altered the lung microenvironment

Hormone-refractory and metastatic prostate cancer (PCa) both result in therapeutic failure. Developing PCa animal model is critical to understand the cancer progression and to access therapeutic effects. Here, we established the orthotopic xenograft of androgen-independent PCa cell line, 22Rv1, in nude mouse model and cultured the metastatic cancer cells. The same procedure was repeated to evolve highly metastatic cells, 22Rv1-LN3. In experimental metastasis, 22Rv1-LN3 can colonize and grow in the LN, lung and brain through tail vein injection but 22Rv1 cell failed to colonize in these organs. Besides, intracardiac injection of 22Rv1-LN3 also caused bone metastasis. In the model, we found 22Rv1-LN3 cell have higher protease activity (e.g. matriptase and MMP9) along with lower level of protease inhibitors, (e.g. HAI-2, a matriptase inhibitor and TIMP2/TIMP3). Transcriptional level of these genes determined the in vitro invasion activity and in vivo tumorigenicity. Given the differential capacity to seed different tissues, we further analyze the stem cell property by tumorsphere assay and in vivo transplantation with a reduced cell number. Sphere-formation rate in 22Rv1-LN3 cells was 8% compared to only 0.1% in 22Rv1 cells. Tumorigenicity of 22Rv1-LN3 cells in orthotopic transplantation was 100% (8/8) compared to 20% (2/10) in 22Rv1 cells. Moreover, primary tumor of 22Rv1-LN3 cells developed spontaneous metastases in lymph nodes and lung at 8-week, whereas 22Rv1 cells hardly metastasized even at 14-week. As analyzed by qRT-PCR, primary 22Rv1-LN3 tumor vs. 22Rv1-Luc2 induced higher levels of Arginase and iNOS expression in lung tissue, which indicates the proclivity for metastatic niche formation. In conclusion, this PCa progression model not only elevated the malignant properties of cancer cells but also influenced the tumor microenvironment.

Citation Format: Sheue-Fen Tzeng, Chin-Hsien Tsai, Ming-Shyue Lee, Pei-Wen Hsiao. High malignant prostate cancer cells developed enhanced tumor-initiating/metastatasis-initiating activity and altered the lung microenvironment. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B85. doi:10.1158/1538-7445.CHTME14-B85

Abstract A58: Characterized herbal extract of Wedelia chinensis suppresses prostate cancer growth and metastasis by targeting multiple intrinsic pathways and modulating immune cells

We previously demonstrated that the principal active compounds (wedelolectone, luteolin, and apigenin) in the ethanol extract of Wedelia chinensis synergistically inhibit human prostate carcinoma 22Rv1 cell growth and that this extract therefore has potential for use as a prostate cancer (PCa) therapy. Here, we developed a standardized preparation for a W. chinensis ethanol extract that is enriched in the principal active compounds. A comparison of the effect of herbal treatment, androgen ablation therapy, and a combination of the two on the development of androgen-dependent LNCaP tumors in a mouse model showed that the herbal extract alone decreased androgen-induced tumor growth and when in combination with androgen ablation therapy, resulted in more potent inhibition of both tumor growth and cancer metastasis. Our study demonstrated this herbal remedy simultaneously inhibited androgen receptor, NFκB and HER2/3-AKT signaling pathways to induce cell apoptosis. Importantly, our herbal remedy diminished androgen receptor overexpression and AKT activation induced by androgen ablation thus preventing castration-resistant PCa development. Moreover, the herbal remedy standing-alone curbed chemokine expression from hormone-refractory PC-3 tumor and consequently restrained the mobilization of CD11b+Gr1+ myeloid cells in tumor-bearing mice, which effectively inhibited PCa growth and metastasis. In conclusion, this standardized preparation of W. chinensis ethanol extract improved the outcome of PCa therapy either as an add-on to hormonal therapy for androgen-dependent disease or as a monotherapy for hormone-refractory disease.

Citation Format: Chin-Hsien Tsai, Sheue-Fen Tzeng, Pei-Wen Hsiao. Characterized herbal extract of Wedelia chinensis suppresses prostate cancer growth and metastasis by targeting multiple intrinsic pathways and modulating immune cells. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr A58. doi:10.1158/1538-7445.CHTME14-A58

The tetraindole SK228 reverses the epithelial-to-mesenchymal transition of breast cancer cells by up-regulating members of the miR-200 family

The results of recent studies have shown that metastasis, the most common malignancy and primary cause of mortality promoted by breast cancer in women, is associated with the epithelial-to-mesenchymal transition (EMT). The results of the current study show that SK228, a novel indole containing substance, exhibits anti-cancer activity. In addition, the effects of SK228 on the regulation of EMT in breast cancer cells as well as the underlying mechanism have been explored. SK228 was observed to induce a fibroblastoid to epithelial-like change in the appearance of various breast cancer cell lines and to suppress the migration and invasion of these cancer cells in vitro. Moreover, expression of E-cadherin was found to increase following SK228 treatment whereas ZEB1 expression was repressed. Expression of other major EMT inducers, including ZEB2, Slug and Twist1, is also repressed by SK228 as a consequence of up-regulation of members of the miR-200 family, especially miR-200c. The results of animal studies demonstrate that SK228 treatment leads to effective suppression of breast cancer growth and metastasis in vivo. The observations made in this investigation show that SK228 reverses the EMT process in breast cancer cells via an effect on the miR-200c/ZEB1/E-cadherin signalling pathway. In addition, the results of a detailed analysis of the in vivo anti-cancer activities of SK228, carried out using a breast cancer xenograft animal model, show that this substance is a potential chemotherapeutic agent for the treatment of breast cancer.

Abstract C53: rVP1 inhibits prostate cancer metastasis via suppression of Jagged1

Jagged1, a NOTCH ligand, has been shown to correlate with poor prognosis and metastasis of prostate cancer (CaP). CaP is a leading cause of cancer death among men worldwide. There is currently no effective therapeutic strategy for patients with castration-resistant prostate cancer (CRPC) which is defined as continued growth of CaP despite the suppression of male hormones. We previously reported that recombinant capsid protein VP1 (rVP1) of foot-and-mouth disease virus causes cell apoptosis of PC-3, a CRPC, via integrin β1 in vitro. Herein, we demonstrate that rVP1 inhibited cell migration/invasion at a non-toxic concentration and reduced the expression level of Jagged1 and phosphorylation of Akt (Ser 473) and IKKα/β (Ser 176/180) of PC-3 cells in vitro. This inhibition was abolished by integrin β1 blocking antibody, knockdown of integrin β1, or a constitutively active Akt. Furthermore, intravenous administration of rVP1 induced tumor apoptosis, suppressed tumor Jagged1 expression level, reduced primary-tumor spread to lymph nodes and bone, and prolonged the survival time of tumor-bearing mice in an orthotopic PC-3 xenograft model. Recombinant VP1 retarded tumor expansion within the bone and tumor-induced osteolysis in an experimental model of bone metastasis made by injecting PC-3 cells carrying the luciferase gene into mouse left ventricle. Finally, in vivo vascular permeability analyses showed that rVP1 specifically targeted tumor cells by penetrating leaky tumor vasculature. Recombinant VP1 may thus suppress Jagged1 expression of CaP cells by inhibiting the integrin β1/Akt/NF-κB signaling pathway to attenuate expansion of bone metastases and tumor-induced osteolysis in CRPC.

Citation Format: Jui-Ling Wang, Shao-Wen Hung, Chi-Ming Liang, Pei-Wen Hsiao, Shu-Mei Liang. rVP1 inhibits prostate cancer metastasis via suppression of Jagged1. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr C53.

Histone demethylase RBP2 promotes lung tumorigenesis and cancer metastasis

The retinoblastoma binding protein RBP2 (KDM5A) is a histone demethylase that promotes gastric cancer cell growth and is enriched in drug-resistant lung cancer cells. In tumor-prone mice lacking the tumor suppressor gene RB or MEN1, genetic ablation of RBP2 can suppress tumor initiation, but the pathogenic breadth and mechanistic aspects of this effect relative to human tumors have not been defined. Here, we approached this question in the context of lung cancer. RBP2 was overexpressed in human lung cancer tissues where its depletion impaired cell proliferation, motility, migration, invasion, and metastasis. RBP2 oncogenicity relied on its demethylase and DNA-binding activities. RBP2 upregulated expression of cyclins D1 and E1 while suppressing the expression of cyclin-dependent kinase inhibitor p27 (CDKN1B), each contributing to RBP2-mediated cell proliferation. Expression microarray analyses revealed that RBP2 promoted expression of integrin-β1 (ITGB1), which is implicated in lung cancer metastasis. Mechanistic investigations established that RBP2 bound directly to the p27, cyclin D1, and ITGB1 promoters and that exogenous expression of cyclin D1, cyclin E1, or ITGB1 was sufficient to rescue proliferation or migration/invasion, respectively. Taken together, our results establish an oncogenic role for RBP2 in lung tumorigenesis and progression and uncover novel RBP2 targets mediating this role.

Dietary uptake of Wedelia chinensis extract attenuates dextran sulfate sodium-induced colitis in mice

SCOPE

Traditional medicinal herbs are increasingly used as alternative therapies in patients with inflammatory diseases. Here we evaluated the effect of Wedelia chinensis, a medicinal herb commonly used in Asia, on the prevention of dextran sulfate sodium (DSS)-induced acute colitis in mice. General safety and the effect of different extraction methods on the bioactivity of W. chinensis were also explored.

METHODS AND RESULTS

C57BL/6 mice were administrated hot water extract of fresh W. chinensis (WCHF) orally for one week followed by drinking water containing 2% DSS for nine days. WCHF significantly attenuated the symptoms of colitis including diarrhea, rectal bleeding and loss of body weight; it also reduced the shortening of colon length and histopathological damage caused by colonic inflammation. Among four W. chinensis extracts prepared using different extraction techniques, WCHF showed the highest anti-colitis efficacy. Analyses of specific T-cell regulatory cytokines (TNF-α, IL-4, IFN-γ, IL-17, TGF-β, IL-12) revealed that WCHF treatment can suppress the Th1 and Th17, but not Th2, responses in colon tissues and dendritic cells of DSS-induced colitis mice. A 28-day subacute toxicity study showed that daily oral administration of WCHF (100, 500, 1000 mg/kg body weight) was not toxic to mice.

CONCLUSION

Together, our findings suggest that specific extracts of W. chinensis have nutritional potential for future development into nutraceuticals or dietary supplements for treatment of inflammatory bowel disease.

Curcumin-targeting pericellular serine protease matriptase role in suppression of prostate cancer cell invasion, tumor growth, and metastasis

Curcumin has been shown to possess potent chemopreventive and antitumor effects on prostate cancer. However, the molecular mechanism involved in curcumin's ability to suppress prostate cancer cell invasion, tumor growth, and metastasis is not yet well understood. In this study, we have shown that curcumin can suppress epidermal growth factor (EGF)- stimulated and heregulin-stimulated PC-3 cell invasion, as well as androgen-induced LNCaP cell invasion. Curcumin treatment significantly resulted in reduced matrix metalloproteinase 9 activity and downregulation of cellular matriptase, a membrane-anchored serine protease with oncogenic roles in tumor formation and invasion. Our data further show that curcumin is able to inhibit the induction effects of androgens and EGF on matriptase activation, as well as to reduce the activated levels of matriptase after its overexpression, thus suggesting that curcumin may interrupt diverse signal pathways to block the protease. Furthermore, the reduction of activated matriptase in cells by curcumin was also partly due to curcumin's effect on promoting the shedding of matriptase into an extracellular environment, but not via altering matriptase gene expression. In addition, curcumin significantly suppressed the invasive ability of prostate cancer cells induced by matriptase overexpression. In xenograft model, curcumin not only inhibits prostate cancer tumor growth and metastasis but also downregulates matriptase activity in vivo. Overall, the data indicate that curcumin exhibits a suppressive effect on prostate cancer cell invasion, tumor growth, and metastasis, at least in part via downregulating matriptase function.

A VLP vaccine induces broad-spectrum cross-protective antibody immunity against H5N1 and H1N1 subtypes of influenza A virus

The recent threats of influenza epidemics and pandemics have prioritized the development of a universal vaccine that offers protection against a wider variety of influenza infections. Here, we demonstrate a genetically modified virus-like particle (VLP) vaccine, referred to as H5M2eN1-VLP, that increased the antigenic content of NA and induced rapid recall of antibody against HA₂ after viral infection. As a result, H5M2eN1-VLP vaccination elicited a broad humoral immune response against multiple viral proteins and caused significant protection against homologous RG-14 (H5N1) and heterologous A/California/07/2009 H1N1 (CA/07) and A/PR/8/34 H1N1 (PR8) viral lethal challenges. Moreover, the N1-VLP (lacking HA) induced production of a strong NA antibody that also conferred significant cross protection against H5N1 and heterologous CA/07 but not PR8, suggesting the protection against N1-serotyped viruses can be extended from avian-origin to CA/07 strain isolated in humans, but not to evolutionally distant strains of human-derived. By comparative vaccine study of an HA-based VLP (H5N1-VLP) and NA-based VLPs, we found that H5N1-VLP vaccination induced specific and strong protective antibodies against the HA₁ subunit of H5, thus restricting the breadth of cross-protection. In summary, we present a feasible example of direction of VLP vaccine immunity toward NA and HA₂, which resulted in cross protection against both seasonal and pandemic influenza strains, that could form the basis for future design of a better universal vaccine.