Yi-Fang Zhao

Activation of PI3K/Akt/IKK-α/NF-κB signaling pathway is required for the apoptosis-evasion in human salivary adenoid cystic carcinoma: its inhibition by quercetin

Quercetin, one of the most common natural flavonoids, has been reported to possess significant anti-tumor activities both in vitro and in vivo. The present study was to investigate the effects of quercetin on growth and apoptosis in human salivary adenoid cystic carcinoma (ACC). The result from MTT assay showed that quercetin decreased cell viability of both low metastatic cell line ACC-2 and high metastatic cell line ACC-M in a concentration- and time-dependent manner. Moreover, treatment with quercetin resulted in significantly increased apoptosis in ACC cells. Our data also revealed that the apoptosis induced by quercetin treatment was through a mitochondria-dependent pathway which showed close correlation with the down-regulation of the PI3K/Akt/IKK-α/NF-κB pathway. Most importantly, quercetin significantly prevented in vivo growth of ACC xenografts in nude mice, accompanied by induction of tumor cell apoptosis, suppression of NF-κB nuclear translocation, as well as down-regulation of Akt and IKK-α activation. In addition, we explored the clinical significance of the PI3K/Akt/IKK-α/NF-κB signaling axis in ACC by immunohistochemical analysis of tissue specimens followed by the clustering analyses. We determined that the PI3K/Akt/IKK-α/NF-κB pathway is ubiquitously activated in ACC and plays an essential role in the evasion of apoptosis. Taken together, the results from our study implicated that quercetin would be a promising chemotherapeutic agent against ACC through its function of down-regulating the PI3K/Akt/IKK-α/NF-κB signaling pathway.

Autophagy regulates hypoxia‐induced osteoclastogenesis through the HIF‐1α/BNIP3 signaling pathway

Previous studies have implicated that hypoxic stress could enhance osteoclast differentiation; however, the underlying mechanism remains poorly understood. Autophagy is a dynamic lysosomal degradation process that has emerged as an important regulator under hypoxic environment. In the present study, we demonstrate for the first time that autophagy regulates hypoxia‐induced osteoclastogenesis in vitro. We found that exposure of RAW264.7 cells to hypoxia (0.2% oxygen) resulted in enhanced osteoclast differentiation, accompanied by the observation of several specific features of autophagy, including appearance of membranous vacuoles, formation of acidic vesicular organelles, cleavage and recruitment of microtubule‐associated protein 1 light chain 3 (LC3) to autophagosomes, increase in autophagic flux, as well as up‐regulation of autophagy‐related gene (Atg) expression. Moreover, suppression of autophagy with DN‐Atg5K130R or 3‐methyladenine (3‐MA) significantly attenuated the osteoclast differentiation under hypoxic conditions, indicating the functional significance of autophagy in hypoxia‐induced osteoclastogenesis. The data also showed that the activation of autophagy under hypoxic conditions was caused by up‐regulated expression of hypoxia‐inducible factor‐1α (HIF‐1α)‐dependent Bcl‐2 adenovirus E1a 19 kDa interacting protein 3 (BNIP3). Importantly, knockdown of HIF‐1α or BNIP3 obviously abrogated hypoxia‐induced autophagy activation and osteoclastogenesis enhancement. Collectively, our results highlight the fact that autophagy is a pivotal regulator for hypoxia‐induced osteoclast differentiation, which may provide new insight into the pathological processes of osteoclastogenesis under hypoxic stress and help develop new therapeutic strategies for abnormal osteoclastogenesis. J. Cell. Physiol. 227: 639–648, 2012.

Sclerotherapy of Microcystic Lymphatic Malformations in Oral and Facial Regions

PURPOSE Lymphatic malformations (LMs) are benign vascular lesions that can cause disfigurement and functional impairment. Complete surgical resection is often difficult and intralesional injection of sclerosing agents has been proposed as an alternative to the surgery. The aim of this study was to review our experience with pingyangmycin (bleomycin A(5)) injection alone or in combination with surgery for treatment of oral and facial LMs, and to observe the histologic changes after intralesional injection of pingyangmycin. PATIENTS AND METHODS Seventy-nine patients who received intralesional injection of pingyangmycin for the treatment of oral and facial LMs were reviewed. There were 47 males and 32 females, at a ratio of 1 to 0.68. Age ranged from 4 months to 17 years. The sites of the lesions occurred primarily in the tongue, which was found in 37 cases, followed by cheeks in 18, involved lips in 10, parotid gland in 7, oropharynx in 5, and floor of the mouth in only 2 cases. Among them, 42 patients received pingyangmycin sclerotherapy solely, 14 patients had sclerotherapy in combination with secondary surgery, and 23 other patients had surgery with sclerotherapy. Patients had been followed up more than 6 months after the last treatment. The rating of the results was 4-graded: excellent, good, fair, and poor (based on clinical outcome). The histologic changes were observed under microscope in 14 resected specimens after the sclerotherapy. RESULTS Primary anatomic locations of 79 LMs involved the face in 25 cases, and the oral cavity in 54. Median number of injections received per child was 4.2 (range, 3 to 8). Among the 79 patients, 44 cases (55.7%) were graded as excellent, 23 cases (29.11%) as good, 10 cases (12.66%) as fair, and 2 cases (2.53%) as poor. There were fewer totally cured or near-normal appearance in the sole sclerotherapy group (42.86%) than in the surgery with the sclerotherapy group (73.91%; P< .05). In specimens resected after pingyangmycin injection, histologic examination showed the destructive lymphatic vessels and obvious stromal fibrosis. CONCLUSIONS Intralesional injection of pingyangmycin was effective for over two thirds of the children with oral and facial LMs. Perioperative sclerotherapy may improve the treatment of these malformations.

CD163+ tumor-associated macrophages correlated with poor prognosis and cancer stem cells in oral squamous cell carcinoma.

Tumor-associated macrophages (TAMs) play an important role in the progression and prognostication of numerous cancers. However, the role and clinical significance of TAM markers in oral squamous cell carcinoma (OSCC) has not been elucidated. The present study was designed to investigate the correlation between the expression of TAM markers and pathological features in OSCC by tissue microarray. Tissue microarrays containing 16 normal oral mucosa, 6 oral epithelial dysplasia, and 43 OSCC specimens were studied by immunohistochemistry. We observed that the protein expression of the TAM markers CD68 and CD163 as well as the cancer stem cell (CSC) markers ALDH1, CD44, and SOX2 increased successively from the normal oral mucosa to OSCC. The expressions of CD68 and CD163 were significantly associated with lymph node status, and SOX2 was significantly correlated with pathological grade and lymph node status, whereas ALDH1 was correlated with tumor stage. Furthermore, CD68 was significantly correlated with CD163, SOX2, and ALDH1 (P < 0.05). Kaplan-Meier analysis revealed that OSCC patients overexpressing CD163 had significantly worse overall survival (P < 0.05). TAM markers are associated with cancer stem cell marker and OSCC overall survival, suggesting their potential prognostic value in OSCC.

Mammalian target of rapamycin regulates isoliquiritigenin-induced autophagic and apoptotic cell death in adenoid cystic carcinoma cells

Previous studies, including those from our laboratory, have demonstrated that isoliquiritigenin (ISL), a flavonoid isolated from licorice, is a promising cancer chemotherapeutic agent. However the mechanisms underlying its anticancer effects are still far from clear. We now show, for the first time, that ISL triggers the mammalian target of rapamycin (mTOR)-dependent autophagic and apoptotic cell death in adenoid cystic carcinoma (ACC). Exposure of both ACC-2 and ACC-M cells to ISL resulted in several specific features for autophagy, including the appearance of membranous vacuoles, formation of acidic vesicular organelles, punctate pattern of LC3 immunostaining, and an increase in autophagic flux. Moreover, ISL treatment also resulted in significantly increased apoptosis in ACC cells. The ISL-mediated autophagic and apoptotic cell death were obviously attenuated by transfection with dominant negative Atg5 (DN-Atg5K130R) plasmids or treatment with 3-methyladenine(3-MA). In additon, the data also revealed that the autophagic and apoptotic cell death induced by ISL occurred through a mTOR-dependent pathway. More importantly, the xenograft model using ACC-M cells provided further evidence of the occurrence of ISL-induced autophagy and apoptosis in vivo, correlating with the suppresson of mTOR activation as well as up-regulation of Atg5 expression. Taken together, these findings in our study suggest that induction of mTOR-dependent autophagic and apoptotic cell death may be an important mechanism in cancer chemotherapy by ISL.

Curcumin Dually Inhibits Both Mammalian Target of Rapamycin and Nuclear Factor-κB Pathways through a Crossed Phosphatidylinositol 3-Kinase/Akt/IκB Kinase Complex Signaling Axis in Adenoid Cystic Carcinoma

Adenoid cystic carcinoma (ACC) is a highly malignant tumor that is generally unresponsive or only weakly responsive to the currently available antineoplastic agents. Thus, novel therapeutic strategies and agents are urgently needed to treat this aggressive neoplasm. Curcumin, a component of turmeric (Curcuma longa), has been shown to have a diversity of antitumor activities. We show here that curcumin is a potent inhibitor of ACC progression in vitro and in vivo. Curcumin concentration-dependently inhibited the growth of ACC cells via induction of apoptosis. The ability of ACC cells to migrate/invade and induce angiogenesis was also significantly attenuated by curcumin, accompanied by the down-regulation of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-2 and -9. Moreover, our data also demonstrated that the inhibitory effects of curcumin on ACC cells were due to its dual inhibition of both mammalian target of rapamycin (mTOR) and nuclear factor-κB (NF-κB) pathways through a crossed phosphatidylinositol 3-kinase/Akt/IκBα kinase signaling axis. Most importantly, curcumin effectively prevented the in vivo growth and angiogenesis of ACC xenografts in nude mice, as revealed by the induction of cell apoptosis and reduction of microvessel density in tumor tissues. In addition, we further assessed the nature activation status of both mTOR and NF-κB pathways in ACC tissues and confirmed the concurrent high activation of these two pathways in ACC for the first time. Taken together, our findings suggest that further clinical investigation is warranted to apply curcumin as a novel chemotherapeutic regimen for ACC because of its dual suppression of both mTOR and NF-κB pathways.

Ultrasmall Magnetically Engineered Ag2Se Quantum Dots for Instant Efficient Labeling and Whole-Body High-Resolution Multimodal Real-Time Tracking of Cell-Derived Microvesicles.

Cell-derived microvesicles (MVs) are natural carriers that can transport biological molecules between cells, which are expected to be promising delivery vehicles for therapeutic purposes. Strategies to label MVs are very important for investigation and application of MVs. Herein, ultrasmall Mn-magnetofunctionalized Ag2Se quantum dots (Ag2Se@Mn QDs) integrated with excellent near-infrared (NIR) fluorescence and magnetic resonance (MR) imaging capabilities have been developed for instant efficient labeling of MVs for their in vivo high-resolution dual-mode tracking. The Ag2Se@Mn QDs were fabricated by controlling the reaction of Mn(2+) with the Ag2Se nanocrystals having been pretreated in 80 °C NaOH solution, with an ultrasmall size of ca. 1.8 nm, water dispersibility, high NIR fluorescence quantum yield of 13.2%, and high longitudinal relaxivity of 12.87 mM(-1) s(-1) (almost four times that of the commercial contrast agent Gd-DTPA). The ultrasmall size of the Ag2Se@Mn QDs enables them to be directly and efficiently loaded into MVs by electroporation, instantly and reliably conferring both NIR fluorescence and MR traceability on MVs. Our method for labeling MVs of different origins is universal and free of unfavorable influence on intrinsic behaviors of MVs. The complementary imaging capabilities of the Ag2Se@Mn QDs have made the long-term noninvasive whole-body high-resolution dual-mode tracking of MVs in vivo realized, by which the dynamic biodistribution of MVs has been revealed in a real-time and in situ quantitative manner. This work not only opens a new window for labeling with QDs, but also facilitates greatly the investigation and application of MVs.

Mammalian Target of Rapamycin Pathway Promotes Tumor-Induced Angiogenesis in Adenoid Cystic Carcinoma: Its Suppression by Isoliquiritigenin through Dual Activation of c-Jun NH2-Terminal Kinase and Inhibition of Extracellular Signal-Regulated Kinase

Tumor-induced angiogenesis is essential for invasive growth and hematogenous metastasis of adenoid cystic carcinoma (ACC), a highly aggressive neoplasm mostly occurring in salivary glands. Previous studies have indicated that strategies directed against angiogenesis will help develop new therapeutic agents for ACC. The Chinese folk medicine licorice has been used for years as a natural remedy for angiogenesis-related diseases. In this study, we examined the effects of isoliquiritigenin (ISL), a flavonoid isolated from licorice, on the growth and viability of ACC cells and observed a concentration-dependent (0–20 μM) inhibition of cell growth without cell death at 24 h. In a further mimic coculture study, ISL effectively suppressed the ability of ACC cells to induce in vitro proliferation, migration, and tube formation of human endothelial hybridoma (EAhy926) cells as well as ex vivo and in vivo angiogenesis, whereas it exerted no effect on EAhy926 cells when added directly or in the presence of vascular endothelial growth factor (VEGF). The data also showed that the specific suppression of tumor angiogenesis by ISL was caused by down-regulation of mammalian target of rapamycin (mTOR) pathway-dependent VEGF production by ACC cells, correlating with concurrent activation of c-Jun NH2-terminal kinase (JNK) and inhibition of extracellular signal-regulated kinase (ERK). Most importantly, ISL also significantly decreased microvessel density within xenograft tumors, associating with the reduction of VEGF production and suppression of the mTOR pathway coregulated by JNK and ERK, as revealed by immunohistochemical studies and clustering analysis. Taken together, our results highlight the fact that ISL is a novel inhibitor of tumor angiogenesis and possesses great therapeutic potential for ACC.

Hyperbranched-hyperbranched polymeric nanoassembly to mediate controllable co-delivery of siRNA and drug for synergistic tumor therapy.

This study reported a flexible nanoplatform constructed on the pH-dependent self-assembly of two kinds of hyperbranched polymers, and then validated its potency as the controllable siRNA/drug co-delivery vehicle for the combination of chemotherapy with RNA interfering (RNAi) therapy. By virtue of pH-reversible phenylboronate linking, phenylboronic acid-tethered hyperbranched oligoethylenimine (OEI600-PBA) and 1,3-diol-rich hyperbranched polyglycerol (HBPO) can be spontaneously interlinked together into a core-corona nanoconstruction. The special buildup of compactly clustering OEI600-PBA units around hydrophobic HBPO aggregate offered significant advantages over parent OEI600-PBA, including strengthened affinity to siRNA, ability of further loading anticancer drug, easier cellular transport, and acidity-responsive release of payloads. To evaluate the co-delivery capability, Beclin1 siRNA and antitumor DOX were used as the therapeutic models in order to suppress the post-chemotherapy survival of tumor cells caused by drug-induced autophagy. The nanoassembly-mediated single delivery of DOX displayed even better anticancer effects than free DOX, demonstrating the superiority of our pH-responsive nano-design. The nanoassembly-mediated co-delivery of siRNA together with DOX can effectively silence Beclin1 gene, suppress DOX-induced autophagy, and consequently provide strong synergism with a significant enhancement of cell-killing effects in cultured cancerous cells. The in vivo combinational treatment was shown to make the tumor more sensitive to DOX chemotherapy while displaying substantially improved safety as compared with the monochemotherapy.

Transformation of Cell‐Derived Microparticles into Quantum‐Dot‐Labeled Nanovectors for Antitumor siRNA Delivery

Cell-derived microparticles (MPs) have been recently recognized as critical intercellular information conveyors. However, further understanding of their biological behavior and potential application has been hampered by the limitations of current labeling techniques. Herein, a universal donor-cell-assisted membrane biotinylation strategy was proposed for labeling MPs by skillfully utilizing the natural membrane phospholipid exchange of their donor cells. This innovative strategy conveniently led to specific, efficient, reproducible, and biocompatible quantum dot (QD) labeling of MPs, thereby reliably conferring valuable traceability on MPs. By further loading with small interference RNA, QD-labeled MPs that had inherent cell-targeting and biomolecule-conveying ability were successfully employed for combined bioimaging and tumor-targeted therapy. This study provides the first reliable and biofriendly strategy for transforming biogenic MPs into functionalized nanovectors.