The impact of Lacticaseibacillus paracasei GMNL-143 toothpaste on gingivitis and oral microbiota in adults: a randomized, double-blind, crossover, placebo-controlled trial

BACKGROUND

This study examines the oral health benefits of heat-killed Lacticaseibacillus paracasei GMNL-143, particularly its potential in oral microbiota alterations and gingivitis improvement.

METHODS

We assessed GMNL-143's in vitro interactions with oral pathogens and its ability to prevent pathogen adherence to gingival cells. A randomized, double-blind, crossover clinical trial was performed on gingivitis patients using GMNL-143 toothpaste or placebo for four weeks, followed by a crossover after a washout.

RESULTS

GMNL-143 showed coaggregation with oral pathogens in vitro, linked to its surface layer protein. In patients, GMNL-143 toothpaste lowered the gingival index and reduced Streptococcus mutans in crevicular fluid. A positive relationship was found between Aggregatibacter actinomycetemcomitans and gingival index changes, and a negative one between Campylobacter and gingival index changes in plaque.

CONCLUSION

GMNL-143 toothpaste may shift oral bacterial composition towards a healthier state, suggesting its potential in managing mild to moderate gingivitis.

TRIAL REGISTRATION

ID NCT04190485 ( https://clinicaltrials.gov/ ); 09/12/2019, retrospective registration.

EXOSC5 maintains cancer stem cell activity in endometrial cancer by regulating the NTN4/integrin β1 signalling axis

Endometrial carcinoma (EC) is a common type of uterine cancer in developed countries, originating from the uterine epithelium. The incidence rate of EC in Taiwan has doubled from 2005. Cancer stem cells (CSCs) are a subpopulation of cancer cells that have high tumorigenicity and play a crucial role in the malignant processes of cancer. Targeting molecules associated with CSCs is essential for effective cancer treatments. This study delves into the role of Exosome component 5 (EXOSC5) in EC. Data from The Cancer Genome Atlas suggests a correlation between high EXOSC5 mRNA expression and unfavorable EC prognosis. EXOSC5 knockdown diminished EC-CSC self-renewal and reduced expression of key cancer stemness proteins, including c-MYC and SOX2. Intriguingly, this knockdown significantly curtailed tumorigenicity and CSC frequency in EC tumor spheres. A mechanistic examination revealed a reduction in netrin4 (NTN4) levels in EXOSC5-depleted EC cells. Moreover, NTN4 treatment amplified EC cell CSC activity and, when secreted, NTN4 partnered with integrin β1, subsequently triggering the FAK/SRC axis to elevate c-MYC activity. A clear positive relation between EXOSC5 and NTN4 was evident in 93 EC tissues. In conclusion, EXOSC5 augments NTN4 expression, activating c-MYC via the integrin β1/FAK/SRC pathway, offering potential avenues for EC diagnosis and treatment.

Salmonella inhibits tumor metastasis by downregulating epithelial cell adhesion molecules through the protein kinase-B/mammalian target of rapamycin signaling pathway

Epithelial cell adhesion molecules (EpCAM) are highly expressed in many carcinomas and regulate the epithelial-mesenchymal transition, which is required for tumor metastasis. Furthermore, EpCAM overexpression induces tumor cells to develop a stem cell-like phenotype and promotes tumor progression. Targeting EpCAM may be a promising approach for inhibiting tumor metastasis and progression. Salmonella treatment suppresses tumor growth and reduces metastatic nodules in tumor-bearing mice. Based on these results, we hypothesized that Salmonella-based treatments could inhibit the expression of metastasis-associated proteins. The dose-dependent Salmonella treatment significantly downregulated the levels of EpCAM and decreased the phosphorylation of protein kinase-B (AKT)/mTOR (mammalian target of rapamycin) pathway, as shown by immunoblotting. In addition, Salmonella treatment increased the levels of epithelial markers and decreased the levels of mesenchymal markers in a dose-dependent manner. Wound-healing and Transwell assays showed that Salmonella treatment significantly reduced tumor cell migration. The mice were intravenously injected with B16F10 and CT26 cells pre-incubated with or without Salmonella, and the survival of tumor-bearing mice in the Salmonella group increased, indicating an antimetastatic effect. Our findings demonstrate that Salmonella plays a role in inhibiting tumor metastasis by downregulating EpCAM via the AKT/mTOR signaling pathway and has great potential for cancer therapy.

Inhibition of Na+/H+ exchanger (NHE) 7 by 5-(N-ethyl-N-isopropyl)-Amiloride displays anti-cancer activity in non-small cell lung cancer by disrupting cancer stem cell activity and downregulating PD-L1 expression

The alkaline intracellular environment of cancer cells is critical for cell proliferation and controlled by various plasma membrane transporters including Na+/H+ exchangers (NHEs). NHEs can also mediate cell behavior by regulating signaling transduction. In this study, we investigated the role of NHE7 in cancer stem cell (CSC) activity in non-small cell lung cancer (NSCLC) cells and the potential therapeutic implications of targeting NHE7 and the associated immune checkpoint molecule PD-L1. By analyzing the database from The Cancer Genome Atlas, we found a positive correlation between SLC9A7 mRNA levels (the gene encoding NHE7) and poor overall survival in lung adenocarcinoma patients. Using 5-(N-ethyl-N-isopropyl)-Amiloride (EIPA) to inhibit NHE7 activity, we observed disrupted cell cycle progression and suppressed NSCLC cell proliferation without inducing apoptosis. Furthermore, EIPA demonstrated a suppressive effect on CSC activity, evidenced by decreased tumorsphere numbers and inhibition of CSC markers such as ALDH1A2, ABCG2, CD44, and CD133. Flow cytometric analysis revealed that EIPA treatment or NHE7 knockdown in NSCLC cells led to downregulated PD-L1 expression, associated with inhibited STAT3 activity. Interestingly, EIPA's CSC-targeting activity was preferentially observed in NSCLC cells overexpressing BMI1, while increased PD-L1 expression was detected in BMI1-overexpressing NSCLC cells. Our findings suggest that targeting NHE7 with inhibitors like EIPA may have therapeutic potential in NSCLC treatment by disrupting cell cycle progression and suppressing CSC activity. The observed increase in PD-L1 expression in BMI1-overexpressing NSCLC cells upon EIPA treatment highlights the potential benefit of combining NHE7 inhibitors with anti-PD-L1 agents as a promising new therapeutic strategy for NSCLC.

Effectiveness of multimedia courses in improving self-care among patients with breast cancer undergoing radiotherapy

BACKGROUND

Ninety percent of patients receiving radiation therapy experience side effects. Busy schedules and intensive health education programs may lead to incomplete education content delivery and inaccurate patient self-care implementation. This study investigated whether multimedia health education improves the accuracy of patient self-care implementation compared with paper-based education.

METHODS

From March 11, 2020 to February 28, 2021, 110 patients were randomly divided into experimental and control groups, each comprising 55 participants. Paper-based materials were used along with multimedia materials. Radiology self-care awareness questionnaires were administered to both groups before the first treatment and on day 10. The differences in radiology self-care awareness between the two groups was analyzed with inferential statistics, independent t tests, categorical data, and Pearson's chi-squared test. Differences between the two groups were considered significant at a p value of < 0.05.

RESULTS

The treatment accuracy rate improved from 10.9 to 79.1% in the control group and from 24.8 to 98.5% in the experimental group, indicating an improvement in both groups. The difference was significant. These results indicate that the intervention could improve the effectiveness of self-care.

CONCLUSIONS

Participants who used pretreatment multimedia health education exhibited a higher rate of having a correct understanding of treatment self-care than did the control group. These findings can inform the development of a patient-centered cancer treatment knowledge base for improved quality of care.

Heat-killed Lacticaseibacillus paracasei GMNL-653 ameliorates human scalp health by regulating scalp microbiome

BACKGROUND

The equilibrium of the scalp microbiome is important for maintaining healthy scalp conditions, including sebum secretion, dandruff, and hair growth. Many different strategies to improve scalp health have been reported; however, the effect of postbiotics, such as heat-killed probiotics, on scalp health remains unclear. We examined the beneficial effects of heat-killed probiotics consisting of Lacticaseibacillus paracasei, GMNL-653, on scalp health.

RESULTS

Heat-killed GMNL-653 could co-aggregate with scalp commensal fungi, Malassezia furfur, in vitro, and the GMNL-653-derived lipoteichoic acid inhibited the biofilm formation of M. furfur on Hs68 fibroblast cells. The mRNA of hair follicle growth factors, including insulin-like growth factor-1 receptor (IGF-1R), vascular endothelial growth factor, IGF-1, and keratinocyte growth factor was up-regulated in skin-related human cell lines Hs68 and HaCaT after treatment with heat-killed GMNL-653. For clinical observations, we recruited 22 volunteer participants to use the shampoo containing the heat-killed GMNL-653 for 5 months and subsequently measured their scalp conditions, including sebum secretion, dandruff formation, and hair growth. We applied polymerase chain reaction (PCR) to detect the scalp microbiota of M. restricta, M. globosa, Cutibacterium acnes, and Staphylococcus epidermidis. A decrease in dandruff and oil secretion and an increase in hair growth in the human scalp were observed after the use of heat-killed GMNL-653-containing shampoo. The increased abundance of M. globosa and the decreased abundance of M. restricta and C. acnes were also observed. We further found that accumulated L. paracasei abundance was positively correlated with M. globosa abundance and negatively correlated with C. acnes abundance. S. epidermidis and C. acnes abundance was negatively correlated with M. globosa abundance and positively correlated with M. restricta. Meanwhile, M. globosa and M. restricta abundances were negatively associated with each other. C. acnes and S. epidermidis abundances were statistically positively correlated with sebum secretion and dandruff, respectively, in our shampoo clinical trial.

CONCLUSION

Our study provides a new strategy for human scalp health care using the heat-killed probiotics GMNL-653-containing shampoo. The mechanism may be correlated with the microbiota shift.

Lacticaseibacillus paracasei GM-080 Ameliorates Allergic Airway Inflammation in Children with Allergic Rhinitis: From an Animal Model to a Double-Blind, Randomized, Placebo-Controlled Trial

Background: Probiotics may facilitate the clinical management of allergic diseases. However, their effects on allergic rhinitis (AR) remain unclear. We examined the efficacy and safety of Lacticaseibacillus paracasei GM-080 in a mouse model of airway hyper-responsiveness (AHR) and in children with perennial AR (PAR) by using a double-blind, prospective, randomized, placebo-controlled design. Methods: The production of interferon (IFN)-γ and interleukin (IL)-12 was measured by using an enzyme-linked immunosorbent assay. GM-080 safety was evaluated via the whole-genome sequencing (WGS) of virulence genes. An ovalbumin (OVA)-induced AHR mouse model was constructed, and lung inflammation was evaluated by measuring the infiltrating leukocyte content of bronchoalveolar lavage fluid. A clinical trial was conducted with 122 children with PAR who were randomized to receive different doses of GM-080 or the placebo for 3 months, and their AHR symptom severity scores, total nasal symptom scores (TNSSs), and Investigator Global Assessment Scale scores were examined. Results: Among the tested L. paracasei strains, GM-080 induced the highest IFN-γ and IL-12 levels in mouse splenocytes. WGS analysis revealed the absence of virulence factors or antibiotic-resistance genes in GM-080. The oral administration of GM-080 at 1 × 10⁷ colony forming units (CFU)/mouse/day for 8 weeks alleviated OVA-induced AHR and reduced airway inflammation in mice. In children with PAR, the oral consumption of GM-080 at 2 × 10⁹ CFU/day for 3 months ameliorated sneezing and improved Investigator Global Assessment Scale scores significantly. GM-080 consumption led to a nonsignificant decrease in TNSS and also nonsignificantly reduced IgE but increased INF-γ levels. Conclusion: GM-080 may be used as a nutrient supplement to alleviate airway allergic inflammation.

Disulfiram/Copper Suppresses Cancer Stem Cell Activity in Differentiated Thyroid Cancer Cells by Inhibiting BMI1 Expression

Differentiated thyroid carcinomas (DTCs), which have papillary and follicular types, are common endocrine malignancies worldwide. Cancer stem cells (CSCs) are a particular type of cancer cells within bulk tumors involved in cancer initiation, drug resistance, and metastasis. Cells with high intracellular aldehyde hydrogenase (ALDH) activity are a population of CSCs in DTCs. Disulfiram (DSF), an ALDH inhibitor used for the treatment of alcoholism, reportedly targets CSCs in various cancers when combined with copper. This study reported for the first time that DSF/copper can inhibit the proliferation of papillary and follicular DTC lines. DSF/copper suppressed thyrosphere formation, indicating the inhibition of CSC activity. Molecular mechanisms of DSF/copper involved downregulating the expression of B lymphoma Mo-MLV insertion region 1 homolog (BMI1) and cell cycle-related proteins, including cyclin B2, cyclin-dependent kinase (CDK) 2, and CDK4, in a dose-dependent manner. BMI1 overexpression diminished the inhibitory effect of DSF/copper in the thyrosphere formation of DTC cells. BMI1 knockdown by RNA interference in DTC cells also suppressed the self-renewal capability. DSF/copper could inhibit the nuclear localization and transcriptional activity of c-Myc and the binding of E2F1 to the BMI1 promoter. Overexpression of c-Myc or E2F1 further abolished the inhibitory effect of DSF/copper on BMI1 expression, suggesting that the suppression of c-Myc and E2F1 by DSF/copper was involved in the downregulation of BMI1 expression. In conclusion, DSF/copper targets CSCs in DTCs by inhibiting c-Myc- or E2F1-mediated BMI1 expression. Therefore, DSF is a potential therapeutic agent for future therapy in DTCs.

Heat-Killed Lactobacilli Preparations Promote Healing in the Experimental Cutaneous Wounds

Probiotics are defined as microorganisms with beneficial health effects when consumed by humans, being applied mainly to improve allergic or intestinal diseases. Due to the increasing resistance of pathogens to antibiotics, the abuse of antibiotics becomes inefficient in the skin and in systemic infections, and probiotics may also provide the protective effect for repairing the healing of infected cutaneous wounds. Here we selected two Lactobacillus strains, L. plantarum GMNL-6 and L. paracasei GMNL-653, in heat-killed format to examine the beneficial effect in skin wound repair through the selection by promoting collagen synthesis in Hs68 fibroblast cells. The coverage of gels containing heat-killed GMNL-6 or GMNL-653 on the mouse tail with experimental wounds displayed healing promoting effects with promoting of metalloproteinase-1 expression at the early phase and reduced excessive fibrosis accumulation and deposition in the later tail-skin recovery stage. More importantly, lipoteichoic acid, the major component of Lactobacillus cell wall, from GMNL-6/GMNL-653 could achieve the anti-fibrogenic benefit similar to the heat-killed bacteria cells in the TGF-β stimulated Hs68 fibroblast cell model. Our study offers a new therapeutic potential of the heat-killed format of Lactobacillus as an alternative approach to treating skin healing disorders.

Nerolidol inhibits proliferation of leiomyoma cells via reactive oxygen species-induced DNA damage and downregulation of the ATM/Akt pathway

Nerolidol (3,7,11-trimethyl-1,6,10-dodecatrien-3-ol), a sesquiterpene alcohol present in aromatic essential oils of numerous plants, has been reported to possess anticancer activity. The potential therapeutic effect of nerolidol on uterine fibroids (UF), the most common benign tumor of the uterus worldwide, is unknown. In this study, we examined the anti-UF potential of nerolidol in ELT3 cells, a rat leiomyoma cell line widely used as an in vitro model, to identify the potential therapeutic agents for UF. We observed that treatment with cis- or trans-nerolidol inhibited cell proliferation in a dose-dependent manner and induced cell cycle arrest in the G1 phase, which was accompanied by reduction in Akt phosphorylation and downregulation of cyclin D1, cyclin-dependent kinase 4 (CDK4), and CDK6 protein expression. The proliferation-inhibiting activity of nerolidol correlated with the generation of intracellular reactive oxygen species (ROS), which was suppressed by N-acetyl-l-cysteine, a ROS inhibitor. Nerolidol treatment also increased the percentage of cells for which tail moment could be calculated using an alkaline comet assay, and induced p-γH2AX^ser139 expression, which indicated induction of DNA damage. We also observed downregulation of ATM and its phosphorylation after nerolidol treatment; furthermore, treatment with KU-55933, an ATM kinase inhibitor, mimicked the inhibitory effects of nerolidol treatment on cell proliferation and Akt phosphorylation. In conclusion, nerolidol displayed anti-UF activity in a leiomyoma cell model via ROS-induced DNA damage and G1 phase cell cycle arrest by inhibiting the expression and activation of the ATM/Akt pathway. Our data suggests that nerolidol is a potential therapeutic agent for UF.

L-Type Amino Acid Transporter 1 Regulates Cancer Stemness and the Expression of Programmed Cell Death 1 Ligand 1 in Lung Cancer Cells

The l-type amino acid transporter 1 (LAT1) is a membranous transporter that transports neutral amino acids for cells and is dysregulated in various types of cancer. Here, we first observed increased LAT1 expression in pemetrexed-resistant non-small cell lung cancer (NSCLC) cells with high cancer stem cell (CSC) activity, and its mRNA expression level was associated with shorter overall survival in the lung adenocarcinoma dataset of the Cancer Genome Atlas database. The inhibition of LAT1 by a small molecule inhibitor, JPH203, or by RNA interference led to a significant reduction in tumorsphere formation and the downregulation of several cancer stemness genes in NSCLC cells through decreased AKT serine/threonine kinase (AKT)/mammalian target of rapamycin (mTOR) activation. The treatment of the cell-permeable leucine derivative promoted AKT/mTOR phosphorylation and reversed the inhibitory effect of JPH203 in the reduction of CSC activity in pemetrexed-resistant lung cancer cells. Furthermore, we observed that LAT1 silencing caused the downregulation of programmed cell death 1 ligand 1 (PD-L1) on lung cancer cells. The PD-L1⁺/LAT1⁺ subpopulation of NSCLC cells displayed great CSC activity with increased expression of several cancer stemness genes. These data suggest that LAT1 inhibitors can serve as anti-CSC agents and could be used in combination with immune checkpoint inhibitors in lung cancer therapy.

A dendrimer-functionalized turn-on fluorescence probe based on enzyme-activated debonding feature of azobenzene linkage

The hypoxic feature of tumors has led to researchers developing hypoxia-activated prodrugs and probes that leverage oxidoreductases overexpressed in tumor tissues.

Reciprocal Regulation Between Indoleamine 2,3-Dioxigenase 1 and Notch1 Involved in Radiation Response of Cervical Cancer Stem Cells

Cervical cancer is the fourth most common cancer in women around the world. Cancer stem cells (CSCs) are responsible for cancer initiation, as well as resistance to radiation therapy, and are considered as the effective target of cancer therapy. Indoleamine 2,3-dioxygenase 1 (IDO1) mediates tryptophan metabolism and T cell suppression, but the immune-independent function of IDO1 in cancer behavior is not fully understood. Using tumorsphere cultivation for enriched CSCs, we firstly found that IDO1 was increased in HeLa and SiHa cervical cancer cells and in these two cell lines after radiation treatment. The radiosensitivity of HeLa and SiHa tumorsphere cells was increased after the inhibition of IDO1 through RNA interference or by the treatment of INCB-024360, an IDO1 inhibitor. With the treatment of kynurenine, the first breakdown product of the IDO1-mediated tryptophan metabolism, the radiosensitivity of HeLa and SiHa cells decreased. The inhibition of Notch1 by shRNA downregulated IDO1 expression in cervical CSCs and the binding of the intracellular domain of Notch (NICD) on the IDO1 promoter was reduced by Ro-4929097, a γ-secretase inhibitor. Moreover, the knockdown of IDO1 also decreased NICD expression in cervical CSCs, which was correlated with the reduced binding of aryl hydrocarbon receptor nuclear translocator to Notch1 promoter. In vivo treatment of INCB-0234360 sensitized SiHa xenograft tumors to radiation treatment in nude mice through increased DNA damage. Furthermore, kynurenine increased the tumorsphere formation capability and the expression of cancer stemness genes including Oct4 and Sox2. Our data provide a reciprocal regulation mechanism between IDO1 and Notch1 expression in cervical cancer cells and suggest that the IDO1 inhibitors may potentially be used as radiosensitizers.

NAD(P)H:quinone oxidoreductase 1 determines radiosensitivity of triple negative breast cancer cells and is controlled by long non-coding RNA NEAT1

Radioresistant cells cause recurrence in patients with breast cancer after they undergo radiation therapy. The molecular mechanisms by which cancer cells obtain radioresistance should be understood to develop radiation-sensitizing agents. Results showed that the protein expression and activity of NAD(P)H:quinone oxidoreductase 1 (NQO1) were upregulated in radioresistant MDA-MB-231 triple-negative breast cancer (TNBC) cells. NQO1 knockdown inhibited the proliferation of NQO1 expressing Hs578t TNBC cells or the radioresistant MDA-MB-231 cells, whereas NOQ1 overexpression increased the survival of MDA-MB-231 cells, which lack of NQO1 expression originally, under irradiation. The cytotoxicity of β-lapachone, an NQO1-dependent bioactivatable compound, was greater in radioresistant MDA-MB-231 cells than in parental cells. β-lapachone displayed a radiosensitization effect on Hs578t or radioresistant MBDA-MB-231 cells. The expression of the long noncoding RNA NEAT1 positively regulated the NQO1 expression in radioresistant MDA-MB-231 cells at a translational level rather than at a transcription level. The inhibition of the NEAT1 expression through the CRISPR-Cas9 method increased the sensitivity of radioresistant MDA-MB-231 cells to radiation and decreased their proliferation, the activity of cancer stem cells, and the expression of stemness genes, including BMI1, Oct4, and Sox2. In conclusion, the NQO1 expression in triple-negative breast cancer cells determined their radiosensitivity and was controlled by NEAT1. In addition, NOQ1 bioactivatable compounds displayed potential for application in the development of radiation sensitizers in breast cancer.

GPER-induced signaling is essential for the survival of breast cancer stem cells

G protein‐coupled estrogen receptor‐1 (GPER), a member of the G protein‐coupled receptor (GPCR) superfamily, mediates estrogen‐induced proliferation of normal and malignant breast epithelial cells. However, its role in breast cancer stem cells (BCSCs) remains unclear. Here we showed greater expression of GPER in BCSCs than non‐BCSCs of three patient‐derived xenografts of ER⁻/PR⁺ breast cancers. GPER silencing reduced stemness features of BCSCs as reflected by reduced mammosphere forming capacity in vitro, and tumor growth in vivo with decreased BCSC populations. Comparative phosphoproteomics revealed greater GPER‐mediated PKA/BAD signaling in BCSCs. Activation of GPER by its ligands, including tamoxifen (TMX), induced phosphorylation of PKA and BAD‐Ser118 to sustain BCSC characteristics. Transfection with a dominant‐negative mutant BAD (Ser118Ala) led to reduced cell survival. Taken together, GPER and its downstream signaling play a key role in maintaining the stemness of BCSCs, suggesting that GPER is a potential therapeutic target for eradicating BCSCs.

What's new?

G protein‐coupled estrogen receptor‐1 (GPER) mediates estrogen‐induced proliferation of normal and malignant breast epithelial cells. However, the role of GPER in breast cancer stem cells (BCSC) biology remains unclear. Here, using patient‐derived xenografts of ER–/PR+ breast cancer, the authors found higher expression of GPER in BCSCs than non‐BCSCs. Moreover, the results indicated that stemness features were sustained via GPER‐mediated PKA/BAD phosphorylation. Stimulation by the GPER ligand tamoxifen enhanced BCSC cell viability and population and BAD phosphorylation. The findings revealed a vital role of GPER‐mediated signaling pathways in BCSC survival, suggesting GPER as a potential therapeutic target for eradicating BCSCs.

Abstract 3673: The BMI1/Sp1/IGF1R pathway mediates pemetrexed resistance in non-small cell lung cancer cells

Background: Lung cancer is the leading cause of cancer death in Taiwan and worldwide and non-small cell lung cancers (NSCLCs) account for more than 85% of lung cancers. Pemetrexed is approved for several steps of nonsquamous NSCLC therapy but drug resistance often occurs in long-term treatment. Cancer stem cells (CSCs) are considered as the rare subpopulation of cancer cells with the features of tumor initiation, drug resistance, and metastatic capability. The signaling pathway and potential targets contribute to the maintenance of pemetrexed-resistant cancer stem cell remain unknown.

Methods: To investigate the mechanism of pemetrexed resistance in lung cancers, the pemetrexed-resistant A549 cells were established (A400). The sphere-formation assay, western blot analysis and real-time qPCR were employed to identify cancer stem cells and study their properties.

Result: We first discovered that the pemetrexed-resistant A549 cells (called A400) contained more CSC activity than the parental A549 cells including the increased number of tumorspheres and the upregulation of BMI1, c-Myc, Sox2 and p-IGF1Rtyr1165/1166 expression. The treatment of PTC-209, a BMI1 inhibitor, displayed a greater inhibitory effect in cell proliferation in A400 than A549 cells and it suppressed tumorsphere formation capability of A400 cells. In addition, PTC-209 treatment downregulated the expression of IGF1R, p-IGF1Rtyr1165/1166, and Sp1, a positive regulatory transcriptional factor in IGF1R expression, in A400 cells. We also found that Sp1 was increased in A400 when compared to parental A549 cells. With the treatment of Sp1 inhibitor in A400 cells, the expression of IGF1R was suppressed without changing BMI1 level. Finally, we examined the therapeutic effect of BMI1 inhibition in vivo and resulted found that intraperitoneal administration of PTC-209 enhanced the pemetrexed efficacy in NOD/SCID mice harboring A400 xenograft tumors.

Conclusion: Our data reveal that BMI1/Sp1/IGF1R pathway is upregulated in pemetrexed resistant NSCLCs and targeting BMI1 could be a therapeutic strategy in NSCLCs when pemetrexed resistance occurs.

Citation Format: Wen-Ling Wang, Peng-Ju Chien, Wen-Wei Chang, Bing-Yen Wang. The BMI1/Sp1/IGF1R pathway mediates pemetrexed resistance in non-small cell lung cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3673.

Salmonella inhibits tumor angiogenesis by downregulation of vascular endothelial growth factor

Salmonella is a Gram-negative, facultative anaerobe that is a common cause of host intestinal infections. Salmonella grows under aerobic and anaerobic conditions, and it has been proven capable of inhibiting tumor growth. However, the molecular mechanism by which Salmonella inhibits tumor growth is still unclear. Angiogenesis plays an important role in the development and progression of tumors. We investigated the antitumor effect of Salmonella in a syngeneic murine tumor model. Hypoxia-inducible factor-1 (HIF-1)α plays a significant role in tumor angiogenesis. We examined the molecular mechanism by which Salmonella regulated vascular endothelial growth factor (VEGF), which is an important angiogenic factor. The expression of VEGF in tumor cells was decreased by treatment with Salmonella. The conditioned medium from Salmonella-treated cells inhibited the proliferation of endothelial cells. Salmonella inhibited the expression of HIF-1α as well as downregulated its upstream signal mediator protein kinase B (AKT). Salmonella significantly inhibited tumor growth in vivo, and immunohistochemical studies of the tumors revealed decreased intratumoral microvessel density. These results suggest that Salmonella therapy, which exerts anti-angiogenic activities, represents a promising strategy for the treatment of tumors.

Salmonella Overcomes Drug Resistance in Tumor through P-glycoprotein Downregulation

Chemotherapy is one of effective methods for the treatment of tumor. Patients often develop drug resistance after chemotherapic cycles. Salmonella has potential as antitumor agent. Salmonella used in tandem with chemotherapy had additive effects, providing a rationale for using tumor-targeting Salmonella in combination with conventional chemotherapy. To improve the efficacy and safety of Salmonella, a further understanding of Salmonella interactions with the tumor microenvironment is required. The presence of plasma membrane multidrug resistance protein P-glycoprotein (P-gp) is highly relevant for the success of chemotherapy. Following Salmonella infection, dose-dependent downregulation of P-gp expressions were examined. Salmonella significantly decreased the efflux capabilities of P-gp, as based on the influx of Rhodamine 123 assay. In addition, Salmonella significant reduced the protein express the expression levels of phosph-protein kinase B (P-AKT), phosph-mammalian targets of rapamycin (P-mTOR), and phosph-p70 ribosomal s6 kinase (P-p70s6K) in tumor cells. The Salmonella-induced downregulation of P-gp was rescued by transfection of cells with active P-AKT. Our results demonstrate that Salmonella in tumor sites leads to decrease the expression of P-gp and enhances the combination of Salmonella and 5-Fluorouracil therapeutic effects.

Hsp90α Mediates BMI1 Expression in Breast Cancer Stem/Progenitor Cells through Facilitating Nuclear Translocation of c-Myc and EZH2

Heat shock protein 90 (Hsp90) is a molecular chaperone that facilitates the correct folding and functionality of its client protein. Numerous Hsp90-client proteins are involved in cancer development. Thus, Hsp90 inhibitors have potential applications as anti-cancer drugs. We previously discovered that Hsp90α expression increased in breast cancer stem cells (BCSCs), which can initiate tumorigenesis and metastasis and resist treatment. In the present study, we further demonstrated that 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), an inhibitor of Hsp90, could suppress the self-renewal of BCSCs by downregulating B lymphoma Mo-MLV insertion region 1 homolog (BMI1), a polycomb family member with oncogenic activity in breast cancer. Through immunoprecipitation analysis, we found that BMI1 did not interact with Hsp90α and that the downregulation of BMI1 by 17-DMAG was mediated by the inhibition of c-Myc and enhancement of zeste homolog 2 (EZH2) expression. The transcriptional and BMI1 promoter-binding activities of c-Myc in BCSCs were inhibited by 17-DMAG treatment. The overexpression of EZH2 attenuated the inhibitory effect of 17-DMAG on BMI1 and c-Myc expression. Furthermore, Hsp90α could be co-immunoprecipitated with c-Myc and EZH2 and bind to the BMI1 promoter. Treatment with 17-DMAG decreased the nuclear expression of EZH2 and c-Myc but not that of Hsp90α. In conclusion, our data suggested that Hsp90α could positively regulate the self-renewal of BCSCs by facilitating the nuclear translocation of c-Myc and EZH2 to maintain BMI1 expression.

Near-Infrared-Triggered Photodynamic Therapy toward Breast Cancer Cells Using Dendrimer-Functionalized Upconversion Nanoparticles

Water-soluble upconversion nanoparticles (UCNPs) that exhibit significant ultraviolet, blue, and red emissions under 980-nm laser excitation were successfully synthesized for performing near infrared (NIR)-triggered photodynamic therapy (PDT). The lanthanide-doped UCNPs bearing oleate ligands were first exchanged by citrates to generate polyanionic surfaces and then sequentially encapsulated with NH₂-terminated poly(amido amine) (PAMAM) dendrimers (G4) and chlorine6 (Ce6) using a layer-by-layer (LBL) absorption strategy. Transmission electron microscopy and X-ray diffraction analysis confirm that the hybrid UCNPs possess a polygonal morphology with an average dimension of 16.0 ± 2.1 nm and α-phase crystallinity. A simple calculation derived through thermogravimetric analysis revealed that one polycationic G4 dendrimer could be firmly accommodated by approximately 150 polyanionic citrates through multivalent interactions. Moreover, zeta potential measurements indicated that the LBL fabrication results in the hybrid nanoparticles with positively charged surfaces originated from these dendrimers, which assist the cellular uptake in biological specimens. The cytotoxic singlet oxygen based on the photosensitization of the adsorbed Ce6 through the upconversion emissions can be readily accumulated by increasing the irradiation time of the incident lasers. Compared with that of 660-nm lasers, NIR-laser excitation exhibits optimized in vitro PDT effects toward human breast cancer MCF-7 cells cultured in the tumorspheres, and less than 40% of cells survived under a low Ce6 dosage of 2.5 × 10-7 M. Fluorescence microscopy analysis indicated that the NIR-driven PDT causes more effective destruction of the cells located inside spheres that exhibit significant cancer stem cell or progenitor cell properties. Moreover, an in vivo assessment based on immunohistochemical analysis for a 4T1 tumor-bearing mouse model confirmed the effective inhibition of cancer cell proliferation through cellular DNA damage by the expression of Ki67 and γH2AXser139 protein markers. Thus, the hybrid UCNPs are a promising NIR-triggered PDT module for cancer treatment.

Hinokitiol up-regulates miR-494-3p to suppress BMI1 expression and inhibits self-renewal of breast cancer stem/progenitor cells

Hinokitiol (β-thujaplicin) is a tropolone-related compound that has anti-microbe, anti-inflammation, and anti-tumor effects. Cancer stem/progenitor cells (CSCs) are a subpopulation of cancer cells with tumor initiation, chemoresistant, and metastatic properties and have been considered the important therapeutic target in future cancer therapy. Previous studies reported that hinokitiol exhibits an anti-cancer activity against murine tumor cells through the induction of autophagy. The current research revealed that hinokitiol suppressed the self-renewal capabilities of human breast CSCs (BCSCs) and inhibited the expression of BMI1 at protein level without suppressing its mRNA. Treatment of hinokitiol in mammospheres induced the expression of miR-494-3p and inhibition of miR-494-3p expression in BCSCs. This treatment abolished the suppressive effects of hinokitiol in mammosphere formation and BMI1 expression. BMI1 is a target of miR-494-3p by luciferase-based 3′UTR reporter assay. Overexpression of miR-494-3p in BCSCs caused the down-regulation of BMI1 protein, inhibition of mammosphere forming capability, and suppression of their tumorigenicity. Moreover, miR-494-3p expression was significantly and inversely correlated with patient survival in two independent public database sets. Furthermore, treatment of hinokitiol in vivo suppressed the growth of xenograft human breast tumors as well as the expression of BMI1 and ALDH1A1 in xenograft tumors. In conclusion, these data suggest that hinokitiol targets BCSCs through the miR-494-3p-mediated down-modulation of BMI1 expression.

PRMT1 expression is elevated in head and neck cancer and inhibition of protein arginine methylation by adenosine dialdehyde or PRMT1 knockdown downregulates proliferation and migration of oral cancer cells

Protein arginine methylation is a post-translational modification that has been implicated in signal transduction, gene transcription, DNA repair and RNA processing. Overexpression or deregulation of protein arginine methyltransferases (PRMTs) have been reported to be associated with various cancers but have not been studied in head and neck cancer (HNC). We investigated the involvement of the modification in HNC using oral cancer cell lines (SAS, OECM-1 and HSC-3) and an immortalized normal oral cells (S-G). The expression levels of the predominant PRMT1 were generally consistent with the levels of asymmetric dimethylarginine (ADMA), highest in SAS and OECM1, then S-G and low in HSC-3. Upon the treatment with an indirect methyltransferase inhibitor adenosine dialdehyde (AdOx), the ADMA levels in SAS and OECM1, but not that in S-G and HSC-3, decreased significantly. SAS and OECM with high ADMA levels grew faster than HSC-3 and S-G. The growth rate of the fast growing SAS and OECM, but not that of the other two cell lines, decreased significantly upon AdOx treatment. The migration activity of SAS and HSC-3, two cell lines with migration ability also decreased after the AdOx treatment. Immunohistochemical analyses of specimens from typical HNC patients showed strong PRMT1 expression in the tumor cells compared with neighboring normal cells. Knockdown of PRMT1 in SAS cells decreased the levels of PRMT1 and ADMA-containing proteins significantly. These cells showed decreased growth rate, reduced migration activity but increased expression of the epithelial marker E-cadherin. The present study thus provides fundamental background for evaluation of the PRMT1 gene as the therapeutic targets of HNC.

The inhibition of indoleamine 2, 3-dioxygenase 1 by connexin 43

Upregulation of connexin 43 (Cx43) showed potential in enhancing immune surveillance that was suppressed in the tumor microenvironment. The expression of indoleamine 2, 3-dioxygenase (IDO) is one of the crucial factors contributing to tumor immune tolerance by depletion of tryptophan and IDO-mediated tryptophan metabolites. Here, we aim to investigate the role of Cx43 in IDO production in murine tumor by using Cx43 inducers. Resveratrol (trans-3, 5, 4 '-trihydroxystilbene) is a natural plant-derived polyphenol possessing positive effect against cancer. Salmonella enterica serovar choleraesuis (S.C.) was proved to target and inhibit tumor growth. Both of them regulated Cx43 expression in tumor cells and led to either chemosensitizing or immune-activating. In this study, the correlation between Cx43 and IDO were determined by the treatment of resveratrol and S.C. Our data showed an increase in Cx43 while IDO protein and IDO-mediated inhibited effects on T cell decreased after tumor cells are given with resveratrol and S.C.

TREATMENTS

All of which could be inhibited once the expression of Cx43 was blocked. Cx43 involved in IDO regulation might be useful in developing IDO-targeted cancer immune therapy.

Promotion of metastasis of thyroid cancer cells via NRP-2-mediated induction

Tumor-node-metastasis is one of the leading causes of morbidity and mortality in thyroid cancer patients. Upregulation of vascular endothelial growth factor-C (VEGF-C) increases the migratory ability of thyroid cancer cells to lymph nodes. Expression of neuropilin-2 (NRP-2), the co-receptor of VEGF-C, has been reported to be correlated with lymph node metastasis in human thyroid cancer. The present study investigated the role of VEGF-C/NRP-2 signaling in the regulation of metastasis of two different types of human thyroid cancer cells. The results indicated that the VEGF-C/NRP-2 axis significantly promoted the metastatic activities of papillary thyroid carcinoma cells through the activation of the mitogen-activated protein kinase (MAPK) kinase (MEK)/extracellular signal-regulated kinase and p38 MAPK signaling cascades. However, neither MEK or p38 MAPK inhibitors produced significant inhibition of the migratory activity and invasiveness regulated by the VEGF-C/NRP-2 axis in follicular thyroid carcinoma cells. Finally, VEGF-C/NRP-2-mediated invasion and migration of thyroid cancer cells required the expression of NRP-2. The present results demonstrate that the promotion of metastasis by VEGF-C is mainly due to the upregulation of NRP-2 in thyroid cancer cells, and this metastatic activity regulated by the VEGF-C/NRP-2 axis provides further insight into the process of tumor metastasis.

miR-494-3p Induces Cellular Senescence and Enhances Radiosensitivity in Human Oral Squamous Carcinoma Cells

Oral squamous cell carcinoma (OSCC) is the most common malignancy of head and neck. Although radiotherapy is used for OSCC treatment, the occurrence of radioresistant cancer cells limits its efficiency. MicroRNAs (miRNAs) are non-coding RNAs with lengths of 18–25 base pairs and known to be involved in carcinogenesis. We previously demonstrated that by targeting B lymphoma Mo-MLV insertion region 1 homolog (Bmi1), miR-494-3p functions as a putative tumor suppressor miRNA in OSCC. In this study, we further discovered that miR-494-3p could enhance the radiosensitivity of SAS OSCC cells and induce cellular senescence. The overexpression of miR-494-3p in SAS cells increased the population of senescence-associated β-galactosidase positive cells, the expression of p16^INK4a and retinoblastoma 1 (RB1), as well as downregulated Bmi1. The knockdown of Bmi1 by lentiviral-mediated delivery of specific short hairpin RNAs (shRNAs) also enhanced the radiosensitivity of SAS cells and the activation of the senescence pathway. Furthermore, the inverse correlation between Bmi1 and miR-494-3p expression was observed among OSCC tissues. Results suggest that miR-494-3p could increase the radiosensitivity of OSCC cells through the induction of cellular senescence caused by the downregulation of Bmi1.

Hinokitiol inhibits vasculogenic mimicry activity of breast cancer stem/progenitor cells through proteasome-mediated degradation of epidermal growth factor receptor

Hinokitiol, alternatively known as β-thujaplicin, is a tropolone-associated natural compound with antimicrobial, anti-inflammatory and antitumor activity. Breast cancer stem/progenitor cells (BCSCs) are a subpopulation of breast cancer cells associated with tumor initiation, chemoresistance and metastatic behavior, and may be enriched by mammosphere cultivation. Previous studies have demonstrated that BCSCs exhibit vasculogenic mimicry (VM) activity via the epidermal growth factor receptor (EGFR) signaling pathway. The present study investigated the anti-VM activity of hinokitiol in BCSCs. At a concentration below the half maximal inhibitory concentration, hinokitiol inhibited VM formation of mammosphere cells derived from two human breast cancer cell lines. Hinokitiol was additionally indicated to downregulate EGFR protein expression in mammosphere-forming BCSCs without affecting the expression of messenger RNA. The protein stability of EGFR in BCSCs was also decreased by hinokitiol. The EGFR protein expression and VM formation capability of hinokitiol-treated BCSCs were restored by co-treatment with MG132, a proteasome inhibitor. In conclusion, the present study indicated that hinokitiol may inhibit the VM activity of BCSCs through stimulating proteasome-mediated EGFR degradation. Hinokitiol may act as an anti-VM agent, and may be useful for the development of novel breast cancer therapeutic agents.

Resveratrol suppresses myofibroblast activity of human buccal mucosal fibroblasts through the epigenetic inhibition of ZEB1 expression

Oral submucous fibrosis (OSF) is a precancerous condition of the oral mucosa without specific therapeutic drugs. We previously demonstrated that the zinc finger E-box binding homeobox 1 (ZEB1) plays a pathogenic role in the induction of the myofibroblast activity of buccal mucosal fibroblasts (BMFs) and contributes to the pathogenesis of OSF. Resveratrol is a natural polyphenolic flavonoid with anti-fibrosis activity in various tissues and has the capability to inhibit ZEB1 in oral cancer cells. We examined the effect of resveratrol on the myofibroblast activity of human primary fibrotic BMFs (fBMFs) derived from OSF tissues. With the collagen contraction assay, resveratrol displayed anti-myofibroblast activity in three fBMF lines. Resveratrol also inhibited the expression of fibrogenic genes at the mRNA and protein levels in a dose- and time-dependent manner. The downregulation of ZEB1 in fBMFs by resveratrol was mediated by epigenetic mechanisms, such as the upregulated expression of miR-200c and the enhancer of zeste homolog 2 (EZH2), as well as the trimethylated lysine 27 of histone H3 (H3K27me3). Resveratrol also increased the binding of H3K27me3 to the ZEB1 promoter. The knockdown of EZH2 in fBMFs caused the upregulation of ZEB1 and suppressed the inhibitory effect of resveratrol. Furthermore, the reversed expression pattern between EZH2 and ZEB1 was observed in 6/8 OSF tissues with twofold upregulation of ZEB1 expression compared with the adjacent normal mucosa. In conclusion, our data suggest that resveratrol epigenetically inhibits ZEB1 expression to suppress the myofibroblast activity of fBMFs and may serve as a dietary supplement for OSF patients.

Tumorsphere as an effective in vitro platform for screening anti-cancer stem cell drugs

Cancer stem cells (CSCs) are a sub-population of cells within cancer tissues with tumor initiation, drug resistance and metastasis properties. CSCs also have been considered as the main cause of cancer recurrence. Targeting CSCs have been suggested as the key for successful treatment against cancer. Tumorsphere cultivation is based on culturing cancer cells onto ultralow attachment surface in serum-free media under the supplementation with growth factors such as epidermal growth factor and basic fibroblast growth factor. Tumorsphere cultivation is widely used to analyze the self-renewal capability of CSCs and to enrich these cells from bulk cancer cells. This method also provides a reliable platform for screening potential anti-CSC agents. The in vitro anti-proliferation activity of potential agents selected from tumorsphere assay is more translatable into in vivo anti-tumorigenic activity compared with general monolayer culture. Tumorsphere assay can also measure the outcome of clinical trials for potential anti-cancer agents. In addition, tumorsphere assay may be a promising strategy in the innovation of future cancer therapeutica and may help in the screening of anti-cancer small-molecule chemicals.

Hinokitiol induces autophagy in murine breast and colorectal cancer cells

Hinokitiol is found in the heartwood of cupressaceous plants and possesses several biological activities. Hinokitiol may play an important role in anti-inflammation and antioxidant processes, making it potentially useful in therapies for inflammatory-mediated disease. Previously, the suppression of tumor growth by hinokitiol has been shown to occur through apoptosis. Programmed cell death can also occur through autophagy, but the mechanism of hinokitiol-induced autophagy in tumor cells is poorly defined. We used an autophagy inhibitor (3-methyladenine) to demonstrate that hinokitiol can induce cell death via an autophagic pathway. Further, we suggest that hinokitiol induces autophagy in a dose-dependent manner. Markers of autophagy were increased after tumor cells were treated with hinokitiol. In addition, immunoblotting revealed that the levels of phosphoprotein kinase B (P-AKT), phosphomammalian target of rapamycin (P-mTOR), and phospho-p70 ribosomal s6 kinase (P-p70S6K) in tumor cells were decreased after hinokitiol treatment. In conclusion, our results indicate that hinokitiol induces the autophagic signaling pathway via downregulation of the AKT/mTOR pathway. Therefore, our findings show that hinokitiol may control tumor growth by inducing autophagic signaling.

Resveratrol Enhances Chemosensitivity in Mouse Melanoma Model Through Connexin 43 Upregulation

Although current studies indicate that resveratrol exhibits potential antitumor activities, the precise mechanisms of its beneficial effects combined with chemotherapy are not fully understood. This work is warranted to elucidate the underlying mechanism of antitumor effects by the combination therapy of resveratrol and cisplatin. The presence of functional gap junctions is highly relevant for the success of chemotherapy. Gap junctions mediate cell communication by allowing the passage of molecules from one cell to another. Connexin (Cx) 43 is ubiquitous and reduced in a variety of tumor cells. Cx43 may influence the response of tumor cells to treatments by facilitating the passage of antitumor drugs or death signals between neighboring tumor cells. Following resveratrol treatment, dose-dependent upregulation of Cx43 expressions was observed. In addition, gap junction intercellular communication was increased. To study the mechanism underlying these resveratrol-induced Cx43 expressions, we found that resveratrol induced a significant increase in mitogen-activated protein kinases (MAPK) signaling pathways. The MAPK inhibitors significantly reduced the expression of Cx43 protein after resveratrol treatment. Specific knockdown of Cx43 resulted in a reduction of cell death after resveratrol and cisplatin treatment. Our results suggest that treatment of resveratrol in tumor leads to increase Cx43 gap junction communication and enhances the combination of resveratrol and cisplatin therapeutic effects. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 877-886, 2015.

Abstract 3018: SHIP2 plays an oncogenic role in breast cancer stem cells through JNK/vimentin activation and its phosphatase activity

Background and Objectives: Over-expression of SH2-containing-5’-inositol phosphatase-2 (SHIP2) which converts phosphatidylinositol (3,4,5)-trisphosphate [PI(3,4,5)P3] into phosphatidylinositol (3,4)-biphosphate [PI(3,4)P2] has been shown to correlate with decreased disease-free survival in breast cancer. However, its role in breast cancer stem cells (BCSCs) remains unclear.

Results: We analyzed 60 clinical breast cancer specimens and found that the percentage of SHIP2+ cells was positively correlated with that of CD24-CD44+ cells. Among 20 estrogen receptor (ER)-negative samples, 17 had greater SHIP2 expression in CD24-CD44+ subpopulation than the remaining subpopulation. Examination of mouse xenografts derived from primary human breast cancer specimens revealed that SHIP2 protein and its tyrosine 1135 phosphorylation were significantly higher in BCSCs, identified as CD24-CD44+ or ALDH+, than non-BCSCs. SHIP2 silencing or inhibitor of SHIP2 phosphatase significantly decreased mammosphere-forming efficiency, percentage of ALDH+ subpopulation in vitro and tumorigenicity of BCSCs in vivo. SHIP2 shRNA knockdown and SHIP2 phosphatase inhibitor suppressed p-AktSer473 levels. Addition of PI(3,4)P2 could partially rescue Akt phosphorylation and ALDH+ subpopulation in SHIP2-overexpressing AS-B634 cells treated with SHIP2 phosphatase inhibitor. Whereas, PI(3,4)P2 failed to reverse the effects of SHIP2-silencing on Akt activation and ALDH+ subpopulation. Futhermore, over-expression of SHIP2 enhanced the expression of epithelial-mesenchymal transition markers including vimentin (VIM), which was mainly expressed in ER-negative breast cancer cells with higher level in mammospheres than monolayer culture. Ablation of c-Jun N-terminal kinase 1 (JNK1), JNK2 or VIM hampered the increases of both ALDH+ population and tumorigenicity induced by SHIP2 over-expression. BCSCs displayed greater expression of phospho-JNK than non-BCSCs. Futhermore, silencing of JNK suppressed the upregulation of VIM by SHIP2 in breast cancer.

Conclusion: Our study is the first to demonstrate that SHIP2 is crucial for maintaining the properties of BCSCs. Within ER-negative breast cancer, there was a significant correlation of greater expression of SHIP2 in BCSCs than non-BCSCs. We documented a novel functional role of SHIP2 in enhancing mammosphere formation and ALDH+ subpopulation in vitro, promoting tumorigenicity in vivo and inducing the expression of EMT markers including VIM. The upregulation of VIM was mediated by JNK activation. Furthermore, the phosphatase activity of SHIP2 also contributed to its role in BCSCs. In summary, our study has uncovered an oncogenic role of SHIP2 in promoting BCSC features and its underlying molecular mechanisms, providing the impetus for the design of novel BCSC-directed therapeutics by targeting SHIP2.

Citation Format: Chiung-Hui Fu, Ruey-Jen Lin, John Yu, Wen-Wei Chang, Guo-Shiou Liao, Wen-Ying Chang, Ling-Ming Tseng, Yi-Fang Tsai, Jyh-Cherng Yu, Alice L. Yu. SHIP2 plays an oncogenic role in breast cancer stem cells through JNK/vimentin activation and its phosphatase activity. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3018. doi:10.1158/1538-7445.AM2014-3018

Astragalus membranaceus modulates Th1/2 immune balance and activates PPARγ in a murine asthma model

Astragalus membranaceus, a traditional Chinese herb, has been used to improve airway inflammation and asthma. The present study investigated whether A. membranaceus has immunotherapeutic effects on asthma, a chronic inflammatory mucosal disease that is associated with excess production of IgE, eosinophilia, T helper 2 (Th2) cytokines, and bronchial hyperresponsiveness. An ovalbumin (OVA)-induced, chronic inflammatory airway murine asthma model was used to examine the status of pulmonary inflammation after the administration of A. membranaceus. The IgE levels in serum and bronchoalveolar lavage fluid showed a tendency to decrease after the administration of A. membranaceus. The number of eosinophils decreased and infiltration of inflammatory cells and collagen deposition declined in lung sections after A. membranaceus administration. The RNA and protein levels of Th2 cytokines and the ratio of the GATA3/T-bet mRNA levels decreased after A. membranaceus treatment. Furthermore, the mRNA level of peroxisome proliferator-activated receptor γ (PPARγ), a nuclear hormone receptor, increased in the lung tissues of A. membranaceus-treated mice. Finally, an A. membranaceus water extract activated PPARγ activity in either human embryonic kidney 293 (HEK293) or A549 cells in a PPARγ-responsive element-containing luciferase reporter assay. These results indicate that A. membranaceus has an inhibitory effect on airway inflammation in a murine model of asthma through modulating the imbalanced relationship between Th1 and Th2 cytokines.

Salmonella as an innovative therapeutic antitumor agent

Lack of specificity of the therapeutic agent is a primary limitation in the treatment of a tumor. The use of preferentially replicating bacteria as therapeutic agents is an innovative approach to tumor treatment. This is based on the observation that certain obligate or facultative anaerobic bacteria are capable of multiplying selectively in tumors and inhibiting their growth. Bacteria have been employed as antitumor agents that are capable of preferentially amplifying within tumors and inhibiting their growth. Moreover, bacteria-derived factors have an immune-stimulation effect. Therefore, bacteria are able to transfer therapeutic genes into the tumor cells using their infective ability. Herein, we introduce the application of bacteria for tumor therapy and focus on Salmonella, which have been widely used for tumor therapy. Salmonella have mainly been applied as gene-delivery vectors, antitumor immune activators and tumor cell death inducers. This study will not only evaluate the therapeutic efficacy of Salmonella for the treatment of tumor but will also elucidate the mechanisms underlying the antitumor activities mediated by Salmonella, which involve host immune responses and cellular molecular responses.

Double homeobox gene, Duxbl, promotes myoblast proliferation and abolishes myoblast differentiation by blocking MyoD transactivation

Homeobox genes encode transcription factors that regulate embryonic development programs including organogenesis, axis formation and limb development. Previously, we identified and cloned a mouse double homeobox gene, Duxbl, whose homeodomain exhibits the highest identity (67 %) to human DUX4, a candidate gene of facioscapulohumeral muscular dystrophy (FSHD). Duxbl proteins have been shown to be expressed in elongated myocytes and myotubes of trunk and limb muscles during embryogenesis. In this study, we found that Duxbl maintained low expression levels in various adult muscles. Duxbl proteins were induced to express in activated satellite cells and colocalized with MyoG, a myogenic differentiating marker. Furthermore, Duxbl proteins were not detected in quiescent satellite cells but detected in regenerated myocytes and colocalized with MyoD and MyoG following cardiotoxin-induced muscle injury. Ectopic Duxbl overexpressions in C2C12 myoblast cells promoted cell proliferation through mainly enhancing cyclin D1 and hyper-phosphorylated retinoblastoma protein but reducing p21 expression. However, Duxbl overexpression in C2C12 cells inhibited myogenic differentiation by decreasing MyoD downstream gene expressions, including M-cadherin, MyoG, p21 and cyclin D3 but not MyoD itself. Duxbl overexpressions also promoted cell proliferation but blocked MyoD-induced myogenic conversion in multipotent mesenchymal C3H10T1/2 cells. In addition, results of a luciferase reporter assay suggest that Duxbl negatively regulated MyoG promoter activity through the proximal two E boxes. In conclusion, these results indicate that Duxbl may play a crucial role in myogenesis and postnatal muscle regeneration by activating and proliferating satellite and myoblast cells.

Epidermal growth factor/heat shock protein 27 pathway regulates vasculogenic mimicry activity of breast cancer stem/progenitor cells

Tumor vascularization, which is mainly contributed by angiogenesis and vascularization, is necessary for tumor maintenance and progression. Vasculogenic mimicry (VM), vascular-like channels which are lack of the involvement of endothelial cells, has been observed in aggressive cancers and also involves in tumor vascularization. Breast cancer stem/progenitor cells (BCSCs) have been identified as a subpopulation of breast cancer cells with markers of CD24(-)CD44(+), high aldehyde dehydrogenase activity (ALDH(+)) or could be enriched by mammosphere cultivation. These cells have been proven to be associated with tumor vascularization. Here we investigated the molecular mechanisms in VM activity of BCSCs. By periodic acid-Schiff or hematoxylin-eosin stain, we found that there were VM structures in two xenografted human breast cancer tissues established from CD24(-)CD44(+) or ALDH(+) cells. Only ALDH(+) or mammosphere-forming BCSCs could form tube structures on matrigel-coated surface as similar as microvascular endothelial cells. Inhibition of the phosphorylation of epidermal growth factor receptor (EGFR) by gefitinib or knockdown of EGFR by lentiviral shRNA abolished the in vitro VM activity of BCSCs. By quercetin treatment, a plant flavonoid compound which is known to suppress heat shock proteins, or siRNA-mediated gene silencing, both Hsp27 expression and VM capability of BCSCs were suppressed. Forced expression of phosphor-mimic form of Hsp27 in ALDH(+) BCSCs could overcome the inhibitory effect of gefitinib. In conclusion, our data demonstrate that VM activity of BCSCs is mediated by EGF/Hsp27 signaling and targeting this pathway may benefit to breast cancer therapy.

Arecoline-induced myofibroblast transdifferentiation from human buccal mucosal fibroblasts is mediated by ZEB1

Oral submucous fibrosis (OSF) is considered as a pre-cancerous condition of the oral mucosa and is highly associated with habitual areca quid chewing. Arecoline is the major alkaloid in areca quid and is thought to be involved in the pathogenesis of OSF. Our previous studies have demonstrated that arecoline could induce epithelial–mesenchymal transition (EMT)-related factors in primary human buccal mucosal fibroblasts (BMFs). Therefore, we investigated the expression of zinc finger E-box binding homeobox 1 (ZEB1), which is a well-known transcriptional factor in EMT, in OSF tissues and its role in arecoline-induced myofibroblast transdifferentiation from BMFs. The expression of ZEB1, as well as the myofibroblast marker α-smooth muscle actin (α-SMA), was significantly increased in OSF tissues, respectively. With immunofluorescence analysis, arecoline induced the formation of α-SMA-positive stress fibres in BMFs expressing nuclear ZEB1. Arecoline also induced collagen contraction of BMFs in vitro. By chromatin immunoprecipitation, the binding of ZEB1 to the α-SMA promoter in BMFs was increased by arecoline. The promoter activity of α-SMA in BMFs was also induced by arecoline, while knockdown of ZEB1 abolished arecoline-induced α-SMA promoter activity and collagen contraction of BMFs. Long-term exposure of BMFs to arecoline induced the expression of fibrogenic genes and ZEB1. Silencing of ZEB1 in fibrotic BMFs from an OSF patient also suppressed the expression of α-SMA and myofibroblast activity. Inhibition of insulin-like growth factor receptor-1 could suppress arecoline-induced ZEB1 activation in BMFs. Our data suggest that ZEB1 may participate in the pathogenesis of areca quid–associated OSF by activating the α-SMA promoter and inducing myofibroblast transdifferentiation from BMFs.

An extract of Rhodobacter sphaeroides reduces cisplatin-induced nephrotoxicity in mice

Cisplatin is used as a treatment for various types of solid tumors. Renal injury severely limits the use of cisplatin. Renal cell apoptosis, oxidative stress, and inflammation contribute to cisplatin-induced nephrotoxicity. Previously, we found that an extract of Rhodobacter sphaeroides (Lycogen™) inhibited proinflammatory cytokines and the production of nitric oxide in activated macrophages in a dextran sodium sulfate (DSS)-induced colitis model. Here, we evaluated the effect of Lycogen™, a potent anti-inflammatory agent, in mice with cisplatin-induced renal injury. We found that attenuated renal injury correlated with decreased apoptosis due to a reduction in caspase-3 expression in renal cells. Oral administration of Lycogen™ significantly reduced the expression of tumor necrosis factor-α and interleukin-1β in mice with renal injury. Lycogen™ reduces renal dysfunction in mice with cisplatin-induced renal injury. The protective effects of the treatment included blockage of the cisplatin-induced elevation in serum urea nitrogen and creatinine. Meanwhile, Lycogen™ attenuated body weight loss and significantly prolonged the survival of mice with renal injury. We propose that Lycogen™ exerts anti-inflammatory activities that represent a promising strategy for the treatment of cisplatin-induced renal injury.

The expression and significance of insulin-like growth factor-1 receptor and its pathway on breast cancer stem/progenitors

Introduction

Dysregulation of the insulin-like growth factor-1 receptor (IGF-1R)/phosphatidylinositol-3-kinase (PI3K)/Akt pathway was shown to correlate with breast cancer disease progression. Cancer stem cells are a subpopulation within cancer cells that participate in tumor initiation, radio/chemoresistance and metastasis. In breast cancer, breast cancer stem cells (BCSCs) were identified as CD24^-CD44⁺ cells or cells with high intracellular aldehyde dehydrogenase activity (ALDH⁺). Elucidation of the role of IGF-1R in BCSCs is crucial to the design of breast cancer therapies targeting BCSCs.

Methods

IGF-1R expression in BCSCs and noncancer stem cells sorted from xenografts of human primary breast cancers was examined by fluorescence-activated cell sorting (FACS), western blot analysis and immunoprecipitation. The role of IGF-1R in BCSCs was assessed by IGF-1R blockade with chemical inhibitor and gene silencing. Involvement of PI3K/Akt/mammalian target of rapamycin (mTOR) as the downstream pathway was studied by their phosphorylation status upon IGF-1R inhibition and the effects of chemical inhibitors of these signaling molecules on BCSCs. We also studied 16 clinical specimens of breast cancer for the expression of phosphor-Akt in the BCSCs by FACS.

Results

Expression of phosphorylated IGF-1R was greater in BCSCs than in non-BCSCs from xenografts of human breast cancer, which were supported by western blot and immunoprecipitation experiments. The sorted IGF-1R-expressing cells displayed features of cancer stem/progenitors such as mammosphere formation in vitro and tumorigenicity in vivo, both of which were suppressed by knockdown of IGF-1R. A specific inhibitor of the IGF-1R, picropodophyllin suppressed phospho-Akt^Ser473 and preferentially decreased ALDH⁺ BCSC populations of human breast cancer cells. Furthermore, picropodophyllin inhibited the capacity of CD24^-CD44⁺ BCSCs to undergo the epithelial-mesenchymal transition process with downregulation of mesenchymal markers. Inhibitors of signal molecules downstream of IGF-1R including PI3K/Akt/mTOR also reduced the ALDH⁺ population of breast cancer cells. Furthermore, the mTOR inhibitor, rapamycin, suppressed BCSCs in vitro and in vivo.

Conclusion

Our data support the notion that IGF-1R is a marker of stemness, and IGF-1R and its downstream PI3K/Akt/mTOR pathway are attractive targets for therapy directed against breast cancer stem/progenitors.

Salmonella enhance chemosensitivity in tumor through connexin 43 upregulation

The use of preferentially replicating bacteria as oncolytic agents is one of the innovative approaches for the treatment of cancer. The capability of Salmonella to disperse within tumors and hence to delay tumor growth was augmented when combined with chemotherapy. This work is warranted to elucidate the underlying mechanism of antitumor effects by the combination therapy of Salmonella and cisplatin. The presence of functional gap junctions is highly relevant for the success of chemotherapy. Following Salmonella treatment, dose- and time-dependent upregulation of connexin 43 (Cx43) expressions were observed. Moreover, Salmonella significantly enhanced gap intercellular communication (GJIC), as revealed by the fluorescent dye scrape loading assay. To study the pathway underlying these Salmonella-induced effects, we found that Salmonella induced a significant increase in mitogen-activated protein kinases (MAPK) signaling pathways. The Salmonella-induced upregulation of Cx43 was prevented by treatment of cells with the phosphorylated p38 inhibitor, but not phosphorylated extracellular signal-regulated kinase (pERK) inhibitor or phosphorylated c-jun N terminal kinase (pJNK) inhibitor. Specific knockdown of Cx43 had an inhibitory effect on GJIC and resulted in a reduction of cell death after Salmonella and cisplatin treatment. Our results suggest that accumulation of Salmonella in tumor sites leads to increase Cx43 gap junction communication and enhances the combination of Salmonella and cisplatin therapeutic effects.

Tracking of mouse breast cancer stem-like cells with Salmonella

Systemic administration of Salmonella to tumor-bearing mice leads to the preferential accumulation within tumor sites and retardation of tumor growth. The cancer stem-like cell (CSC) hypothesis suggests that CSCs are the root of cancer and induce metastasis and recurrence. The objective of this study was to examine if Salmonella could inhibit the growth of CSCs derived from mouse breast cancer. Systemically injected Salmonella preferentially accumulated within tumors for at least three weeks and the bacteria accumulated preferentially not only in subcutaneous but also in orthotopic tumors over livers and spleens at ratios ranging from 1000:1 to 10,000:1. Salmonella were capable of delaying tumor growth and enhancing survival in both subcutaneous and orthotopic tumor models. More strikingly, Salmonella acted to retard tumor growth and extensively prolong the survival time of the mice bearing CSC-induced tumors. Our results also found that Salmonella predominantly, although not exclusively, resided in the CSC regions of the tumor. These data suggest that Salmonella can inhibit the growth of breast cancer by targeting the CSC niche. In conclusion, Salmonella can be used for the management of breast cancer.

Disruption of Type-I IFN pathway ameliorates preservation damage in mouse orthotopic liver transplantation via HO-1 dependent mechanism

Ischemia/reperfusion injury (IRI) remains unresolved problem in clinical organ transplantation. We analyzed the role of Type-I interferon (IFN) pathway in a clinically relevant murine model of extended hepatic cold preservation followed by orthotopic liver transplantation (OLT). Livers from Type-I IFN receptor (IFNAR) knockout (KO) or wild-type (WT) mice (C57/BL6) were harvested, preserved at 4°C in UW solution for 20 h and transplanted to groups of syngeneic IFNAR KO or WT recipients. Liver graft but not recipient IFNAR deficiency was required to consistently ameliorate IRI in OLTs. Indeed, disruption of Type-I IFN signaling decreased serum alanine aminotransferase (sALT) levels (p < 0.001), diminished Suzuki's score of histological OLT damage (p < 0.01) and improved 14-day survival (from 42%[5/12] in WT to 92%[11/12] in IFNAR KO; p < 0.05). Unlike in WT group, IFNAR deficiency attenuated OLT expression of TNF-α, IL-1β, IL-6, MCP-1, CXCL-10, ICAM-1; diminished infiltration by macrophages/PMNs; and enhanced expression of antioxidant HO-1/Nrf2. The frequency of TUNEL+ apoptotic cells and caspase-3 activity/expression selectively decreased in IFNAR KO group. Small interfering (si)RNA-directed targeting of HO-1 restored cardinal features of liver IRI in otherwise resistant IFNAR-deficient OLTs. Thus, intact Type-I IFN signaling is required for hepatic IRI, whereas HO-1 is needed for cytoprotection against innate immunity-dominated organ preservation damage in IFNAR-deficient liver transplants.

Abstract 5197: Quantitative phosphorproteomics identified GPER-initiated PKA signal transduction event in breast cancer stem cell

Human breast cancer stem cells (BCSC) identified recently have the ability to initiate neoplastic growth with differentiation and display higher resistance to chemotherapy and radiotherapy. The allure of targeting this specific group of cells to reduce mortality of disease has attracted research efforts toward BCSC. Although some unique properties of BCSC have been deciphered, the molecular mechanisms are still poorly understood. Here, we applied in-house developed techniques to quantitatively compare the phosphoproteomic profiles between BCSC and non-cancer stem cells (nonCSC) derived from a xenograft of human breast cancer. For quantitative analysis, we utilized a SEMI-strategy for multiplexed label-free quantitation combining pH/acid-controlled IMAC chromatography and LC-MS/MS for relative quantitation of site-specific phosphorylation. This strategy effectively increases the phosphopeptide quantitation coverage. The differentially expressed phosphoproteins were mapped to multiple signaling pathways including NOTCH, CDK/ERK and JAK-STAT pathways, which potentially orchestrate the self renewal and stemness of BCSC. We also demonstrated ∼2 fold greater expression of GPER in BCSC than non-BCSC population, and GPER signaling could induce PKA-mediated phosphorylation of BAD in BCSC. Silencing of GPER via RNAi or mutation of phosphorylation sites of BAD led to reduced proliferation to 40.8 and 53.2 % of control, respectively, and the RNAi silencing of GPER decreased the mammosphere formation of BCSC to 43.5 % of control. These findings implies the importance of GPER and its downstream PKA pathway to the maintenance of stemness characteristics of BCSC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5197. doi:1538-7445.AM2012-5197