Syngeneic mesenchymal stem cells loaded with telomerase-dependent oncolytic adenoviruses enhance anti-metastatic efficacy.

Oncolytic adenoviruses have emerged as a promising therapeutic approach for cancer therapy. However, systemic delivery of the viruses to metastatic tumors remains a major challenge. Mesenchymal stem cells (MSCs) possess tumor tropism property and can be used as cellular vehicles for delivering oncolytic adenoviruses to tumor sites. Since telomerase activity is found in ~90% of human carcinomas, but undetected in normal adult cells, the human telomerase reverse transcriptase gene (TERT) promoter can be exploited for regulating the replication of oncolytic adenoviruses. Here, we evaluated the antitumor effects of syngeneic murine MSCs loaded with the luciferase-expressing, telomerase-dependent oncolytic adenovirus Ad.GS2 (MSC-Ad.GS2) and Ad.GS2 alone on metastatic MBT-2 bladder tumors. MSCs supported a low degree of Ad.GS2 replication, which could be augmented by coculture with MBT-2 cells or tumor-conditioned medium (TCM), suggesting that viral replication is increased when MSC-Ad.GS2 migrates to tumor sites. MBT-2 cells and TCM enhanced viral replication in Ad.GS2-infected MSCs. SDF-1 is a stem cell homing factor. Our results suggest that the SDF-1/STAT3/TERT signaling axis in MSCs in response to the tumor microenvironment may contribute to the enhanced replication of Ad.GS2 carried by MSCs. Notably, we demonstrate the potent therapeutic efficacy of systemically delivered MSC-Ad.GS2 in pleural disseminated tumor and experimental metastasis models using intrapleural and tail vein injection of MBT-2 cells, respectively. Treatment with MSC-Ad.GS2 significantly reduced tumor growth and prolonged the survival of mice bearing metastatic bladder tumors. Since telomerase is expressed in a broad spectrum of cancers, this therapeutic strategy may be broadly applicable.

Preparation of water-resistant antifog hard coatings on plastic substrate.

A novel water resistant antifog (AF) coating for plastic substrates was developed, which has a special hydrophilic/hydrophobic bilayer structure. The bottom layer, acting both as a mechanical support and a hydrophobic barrier against water penetration, is an organic-inorganic composite comprising colloidal silica embedded in a cross-linked network of dipentaethritol hexaacrylate (DPHA). Atop this layer, an AF coating is applied, which incorporates a superhydrophilic species synthesized from Tween-20 (surfactant), isophorone diisocyanate (coupling agent), and 2-hydroxyethyl methacrylate (monomer). Various methods, e.g., FTIR, SEM, AFM, contact angle, and steam test, were employed to characterize the prepared AF coatings. The results indicated that the size and the continuity of the hydrophilic domains on the top surface increased with increasing added amount of T20, however, at the expense of hardness, adhesiveness, and water resistivity. The optimal T20 content was found to be 10 wt %, at which capacity the resultant AF coating was transparent and wearable (5H, hardness) and could be soaked in water for 7 days at 25 °C without downgrading of its AF capability.

Duration for apical barrier formation in necrotic immature permanent incisors treated with calcium hydroxide apexification using ultrasonic or hand filing.

BACKGROUND/PURPOSE: Traumatic injury usually results in pulp necrosis of immature permanent incisors in children aged 7-10 years. Calcium hydroxide apexification is the most common treatment for necrotic, immature permanent teeth. This study compared the duration for apical barrier formation in necrotic immature permanent incisors treated with calcium hydroxide apexification using ultrasonic or hand filing. METHODS: Thirty-two trauma-induced necrotic immature permanent incisors with or without a periapical lesion (PL) were selected from children aged 7-10 years. They were evenly divided into four groups. Teeth in groups 1 (with PL) and 2 (without PL) were treated with ultrasonic filing, and teeth in groups 3 (with PL) and 4 (without PL) were treated with hand filing. The canals were cleaned with 0.2% chlorhexidine solution during treatment and then compactly filled with calcium hydroxide. The patients were followed up once every 1-3 weeks to change the intracanal medication and to detect when the apical barrier formed. RESULTS: The mean duration for apical barrier formation was 11.1 +/- 1.1 weeks, 11.8 +/- 1.0 weeks, 13.3+/-0.9 weeks and 13.4 +/- 0.7 weeks for groups 1, 2, 3 and 4, respectively. Student's t test showed significant differences in the mean duration for apical barrier formation between groups 1+2 and 3 + 4 (p = 0.000), groups 1 and 3 (p = 0.000), and groups 2 and 4 (p = 0.002). These results indicated that teeth treated with ultrasonic filing required a shorter mean duration for apical barrier formation than teeth treated with hand filing regardless of the presence of PL or not. CONCLUSION: Ultrasonic filing with 0.2% chlorhexidine as an irrigant is effective for disinfection of the root canal and can shorten the duration for apical barrier formation in necrotic permanent incisors treated with calcium hydroxide apexification.

Tumor-selective replication of an oncolytic adenovirus carrying oct-3/4 response elements in murine metastatic bladder cancer models.

PURPOSE: Oncolytic adenoviruses are attractive therapeutics for cancer because they selectively replicate in tumors. However, targeting tumor metastasis remains a major challenge for current virotherapy for cancer. Oct-3/4 is specifically expressed in embryonic stem cells and tumor cells. Oct-3/4 highly expressed in cancer cells may be a potential target for cancer therapy. We developed an E1B-55 kDa-deleted adenovirus, designated Ad.9OC, driven by nine copies of Oct-3/4 response element for treating Oct-3/4-expressing metastatic bladder cancer. EXPERIMENTAL DESIGN: We examined the expression of Oct-3/4 in human bladder tumor tissues and bladder cancer cell lines. We also evaluated the cytolytic and antitumor effects of Ad.9OC on bladder cancer cells in vitro and in vivo. RESULTS: Oct-3/4 expression was detected in bladder cancer cell lines, as well as in human bladder tumor tissues. Notably, Oct-3/4 expression was higher in metastatic compared with nonmetastatic bladder cancer cells. Ad.9OC induced higher cytolytic activity in metastatic bladder cancer cells than in their nonmetastatic counterparts, whereas it did not cause cytotoxicity in normal cells. Pharmacologic and short hairpin RNA-mediated Oct-3/4 inhibition rendered bladder cancer cells more resistant to Ad.9OC-induced cytolysis. Replication of Ad.9OC was detected in murine bladder cancer cells and bladder tumor tissues. We also showed the effectiveness of Ad.9OC for treating bladder cancer in subcutaneous, as well as metastatic, bladder tumor models. CONCLUSIONS: Ad.9OC may have therapeutic potential for treating Oct-3/4-expressing tumors. Especially, metastatic bladder tumors are good target for Ad.9OC treatment. Because Oct-3/4 is expressed in a broad spectrum of cancers, Ad.9OC may be broadly applicable.

Epithelial-Mesenchymal Transition Directs Stem Cell Polarity via Regulation of Mitofusin.

Mitochondria are dynamic organelles that have been linked to stem cell homeostasis. However, the mechanisms involved in mitochondrial regulation of stem cell fate determination remain elusive. Here we discover that epithelial-mesenchymal transition (EMT), a key process in cancer progression, induces mitochondrial fusion through regulation of the miR200c-PGC1α-MFN1 pathway. EMT-activated MFN1 forms a complex with PKCζ and is required for PKCζ-mediated NUMB phosphorylation and dissociation from the cortical membrane to direct asymmetric division of mammary stem cells, where fused mitochondria are tethered by MFN1-PKCζ to the cortical membrane and asymmetrically segregated to the stem cell-like progeny with enhanced glutathione synthesis and reactive oxygen species scavenging capacities, allowing sustaining of a self-renewing stem cell pool. Suppression of MFN1 expression leads to equal distribution of the fragmented mitochondria in both progenies that undergo symmetric luminal cell differentiation. Together, this study elucidates an essential role of mitofusin in stem cell fate determination to mediate EMT-associated stemness.

Low-dose etoposide enhances telomerase-dependent adenovirus-mediated cytosine deaminase gene therapy through augmentation of adenoviral infection and transgene expression in a syngeneic bladder tumor model.

The human telomerase reverse transcriptase (hTERT) promoter can selectively drive transgene expression in many telomerase-positive human cancer cells. Here we evaluated combination therapy of adenoviral vector Ad-hTERT-CD encoding E. coli cytosine deaminase (CD) driven by the hTERT promoter and low-dose etoposide (0.1 microg/mL) for treating bladder cancer. Ad-hTERT-CD conferred sensitivity to 5-fluorocytosine (5-FC) in bladder cancer cells, which could be enhanced by etoposide treatment, but not in normal cells. Such effect was correlated with up-regulation of hypoxia-inducible factor (HIF)-1alpha expression. By contrast, etoposide activated p53 and down-regulated hTERT promoter activity in normal cells. Etoposide also increased adenoviral infection via enhancement of coxsackie-adenovirus receptor expression on bladder cancer and normal cells. Combination index analysis revealed that combined therapy of Ad-hTERT-CD (10(9) plaque-forming units)/5-FC (200 mg/kg) with etoposide (2 mg/kg) synergistically suppressed tumor growth and prolonged survival in mice bearing syngeneic MBT-2 bladder tumors. This combination therapy regimen induced complete tumor regression and generated antitumor immunity in 75% of tumor-bearing mice. Furthermore, increased infiltrating CD4(+) and CD8(+) T cells and necrosis within tumors were found in mice receiving combination therapy of Ad-hTERT-CD and etoposide compared with those treated with either treatment alone. Thus, the potential high therapeutic index of the combination therapy may be an appealing therapeutic intervention for bladder cancer. Furthermore, because a majority of human tumors exhibit high telomerase activity, adenovirus-mediated CD gene therapy driven by the hTERT promoter in combination with low-dose etoposide may be applicable to a broad spectrum of cancers.

Leptin-STAT3-G9a Signaling Promotes Obesity-Mediated Breast Cancer Progression.

Obesity has been linked to breast cancer progression but the underlying mechanisms remain obscure. Here we report how leptin, an obesity-associated adipokine, regulates a transcriptional pathway to silence a genetic program of epithelial homeostasis in breast cancer stem-like cells (CSC) that promotes malignant progression. Using genome-wide ChIP-seq and RNA expression profiling, we defined a role for activated STAT3 and G9a histone methyltransferase in epigenetic silencing of miR-200c, which promotes the formation of breast CSCs defined by elevated cell surface levels of the leptin receptor (OBR(hi)). Inhibiting the STAT3/G9a pathway restored expression of miR-200c, which in turn reversed the CSC phenotype to a more differentiated epithelial phenotype. In a rat model of breast cancer driven by diet-induced obesity, STAT3 blockade suppressed the CSC-like OBR(hi) population and abrogated tumor progression. Together, our results show how targeting STAT3-G9a signaling regulates CSC plasticity during obesity-related breast cancer progression, suggesting a novel therapeutic paradigm to suppress CSC pools and limit breast malignancy.

MicroRNA-205 signaling regulates mammary stem cell fate and tumorigenesis.

Dysregulation of epigenetic controls is associated with tumorigenesis in response to microenvironmental stimuli; however, the regulatory pathways involved in epigenetic dysfunction are largely unclear. We have determined that a critical epigenetic regulator, microRNA-205 (miR-205), is repressed by the ligand jagged1, which is secreted from the tumor stroma to promote a cancer-associated stem cell phenotype. Knockdown of miR-205 in mammary epithelial cells promoted epithelial-mesenchymal transition (EMT), disrupted epithelial cell polarity, and enhanced symmetric division to expand the stem cell population. Furthermore, miR-205-deficient mice spontaneously developed mammary lesions, while activation of miR-205 markedly diminished breast cancer stemness. These data provide evidence that links tumor microenvironment and microRNA-dependent regulation to disruption of epithelial polarity and aberrant mammary stem cell division, which in turn leads to an expansion of stem cell population and tumorigenesis. This study elucidates an important role for miR-205 in the regulation of mammary stem cell fate, suggesting a potential therapeutic target for limiting breast cancer genesis.

Zhankuic acid A as a novel JAK2 inhibitor for the treatment of concanavalin A-induced hepatitis.

Fruiting bodies of Taiwanofungus camphoratus have been widely used as an antidote for food poisoning and considered to be a precious folk medicine for anti-inflammation and hepatoprotection. Zhankuic acid A (ZAA) is its major pharmacologically active compound. Janus kinase 2 (JAK2), whose activation is involved in cytokine signaling, plays critical roles in the development and biology of the hematopoietic system. JAK2 has been implicated as a therapeutic target in inflammatory diseases. The HotLig modeling approach was used to generate the binding model for ZAA with JAK2, showing that ZAA could bind to the ATP-binding pocket of JAK2 exclusively via the H-bond. The interaction between ZAA and JAK2 was verified by antibody competition assay. Binding of ZAA to JAK2 reduced antibody recognition of native JAK2. The expressions of phosphorylated JAK2 and STATs were analyzed by immuno-blotting. ZAA reduced the phosphorylation and downstream signaling of JAK2, and inhibited the interferon (IFN)-γ/signal transducer and activator of transcription (STAT) 1/interferon regulatory factor (IRF)-1 pathway. The protective effect of ZAA on liver injury was evaluated in mice by Con-A-induced acute hepatitis. Pre-treatment with ZAA also significantly ameliorated acute liver injury in mice. Therefore, ZAA can inhibit JAK2 phosphorylation and protect against liver injury during acute hepatitis in mice. In this study, we present data that ZAA exerts anti-inflammatory effects through the JAK2 signaling pathway. As such, ZAA may be a potential therapeutic agent for the treatment of inflammatory diseases.

Oct-3/4 expression reflects tumor progression and regulates motility of bladder cancer cells.

Cancer and embryonic stem cells exhibit similar behavior, including immortal, undifferentiated, and invasive activities. Here, we show that in clinical samples bladder tumors with intense expression of stem cell marker Oct-3/4 (also known as POU5F1) are associated with further disease progression, greater metastasis, and shorter cancer-related survival compared with those with moderate and low expressions. Expression of Oct-3/4 is detected in human bladder transitional cell carcinoma samples and cell lines. Overexpression of Oct-3/4 enhances, whereas knockdown of Oct-3/4 expression by RNA interference reduces, migration and invasion of bladder cancer cells. Oct-3/4 can up-regulate fibroblast growth factor-4 and matrix metalloproteinase-2 (MMP-2), MMP-9, and MMP-13 production, which may contribute to tumor metastasis. Finally, we show that Ad5WS4, an E1B-55 kD-deleted adenovirus driven by the Oct-3/4 promoter, exerts potent antitumor activity against bladder cancer in a syngeneic murine tumor model. Therefore, our results implicate that Oct-3/4 may be useful as a novel tumor biological and prognostic marker and probably as a potential therapeutic target for bladder cancer.