Jiyou Han

Enhanced NIR radiation-triggered hyperthermia by mitochondrial targeting.

Mitochondria are organelles that are readily susceptible to temperature elevation. We selectively delivered a coumarin-based fluorescent iron oxide nanoparticle, Mito-CIO, to the mitochondria. Upon 740 nm laser irradiation, the intracellular temperature of HeLa cells was elevated by 2.1 °C within 5 min when using Mito-CIO, and the treatment resulted in better hyperthermia and a more elevated cytotoxicity than HeLa cells treated with coumarin iron oxide (CIO), which was missing the mitochondrial targeting unit. We further confirmed these results in a tumor xenograft mouse model. To our knowledge, this is the first report of a near-infrared laser irradiation-induced hyperthermic particle targeted to mitochondria, enhancing the cytotoxicity in cancer cells. Our present work therefore may open a new direction in the development of photothermal therapeutics.

Highly selective two-photon imaging of cysteine in cancerous cells and tissues

Abnormal concentrations of Cys have been reported to be implicated in various health problems, including cancer, neuropathy, and cardiomyopathy. We present a novel two-photon fluorescent probe for the specific recognition of cysteine over homocysteine and glutathione, and the bioapplication of this probe for the imaging of live cancerous cells and thick tissues.

Overcoming the Limits of Hypoxia in Photodynamic Therapy: A Carbonic Anhydrase IX-Targeted Approach

A major challenge in photodynamic cancer therapy (PDT) is avoiding PDT-induced hypoxia, which can lead to cancer recurrence and progression through activation of various angiogenic factors and significantly reduce treatment outcomes. Reported here is an acetazolamide (AZ)-conjugated BODIPY photosensitizer (AZ-BPS) designed to mitigate the effects of PDT-based hypoxia by combining the benefits of anti-angiogenesis therapy with PDT. AZ-BPS showed specific affinity to aggressive cancer cells (MDA-MB-231 cells) that overexpress carbonic anhydrase IX (CAIX). It displayed enhanced photocytotoxicity compared to a reference compound, BPS, which is an analogous PDT agent that lacks an acetazolamide unit. AZ-BPS also displayed an enhanced in vivo efficacy in a xenograft mouse tumor regrowth model relative to BPS, an effect attributed to inhibition of tumor angiogenesis by both PDT-induced ROS generation and CAIX knockdown. AZ-BPS was evaluated successfully in clinical samples collected from breast cancer patients. We thus believe that the combined approach described here represents an attractive therapeutic approach to targeting CAIX-overexpressing tumors.

Biochemical and morphological effects of hypoxic environment on human embryonic stem cells in long-term culture and differentiating embryoid bodies

The mammalian reproductive tract is known to contain 1.5–5.3% oxygen (O2), but human embryonic stem cells (hESCs) derived from preimplantation embryos are typically cultured under 21% O2 tension. The aim of this study was to investigate the effects of O2 tension on the long-term culture of hESCs and on cell-fate determination during early differentiation. hESCs and embryoid bodies (EBs) were grown under different O2 tensions (3, 12, and 21% O2). The expression of markers associated with pluripotency, embryonic germ layers, and hypoxia was analyzed using RTPCR, immunostaining, and Western blotting. Proliferation, apoptosis, and chromosomal aberrations were examined using BrdU incorporation, caspase-3 immunostaining, and karyotype analysis, respectively. Structural and morphological changes of EBs under different O2 tensions were comparatively examined using azan- and hematoxylineosin staining, and scanning and transmission electron microscopy. Mild hypoxia (12% O2) increased the number of cells expressing Oct4/Nanog and reduced BrdU incorporation and aneuploidy. The percentage of cells positive for active caspase-3, which was high during normoxia (21% O2), gradually decreased when hESCs were continuously cultured under mild hypoxia. EBs subjected to hypoxia (3% O2) exhibited well-differentiated microvilli on their surface, secreted high levels of collagen, and showed enhanced differentiation into primitive endoderm. These changes were associated with increased expression of Foxa2, Sox17, AFP, and GATA4 on the EB periphery. Our data suggest that mild hypoxia facilitates the slow mitotic division of hESCs in long-term culture and reduces the frequency of chromosomal abnormalities and apoptosis. In addition, hypoxia promotes the differentiation of EBs into extraembryonic endoderm.

Cancer Targeted Enzymatic Theranostic Prodrug: Precise Diagnosis and Chemotherapy

UNLABELLED The development of targeted and effective theranostic (therapeutic and diagnostic) chemotherapeutic agents is highly desirable for precise diagnosis and treatment of cancer. To realize this goal, we developed a cancer-targeting and enzyme-triggered theranostic prodrug 1, containing 7-ethyl-10-hydroxycamptothecin (SN-38), a well-known anticancer drug, which inhibits topoisomerase I in the cell nucleus; hydroquinone as an enzyme-triggered moiety; and biotin as a cancer targeting unit. Enzyme-triggered theranostic prodrug 1 selectively targets cancer cells and is subsequently activated in the presence of NAD(P)H quinone oxidoreductase-1 (NQO1), a cytosolic flavoprotein that catalyzes the two-electron reduction of quinone moieties with the concomitant consumption of NADH or NADPH as electron donors. High levels of NQO1 were found in a variety of cancer cell lines compared to healthy cells, and therefore, it is an excellent target for the development of cancer targeted drug delivery systems. Upon preferential cancer cell delivery and uptake, aided by biotin, the enzyme-triggered theranostic prodrug 1 is cleaved by NQO1, with the subsequent release of SN-38, inhibiting topoisomerase I, leading to apoptosis. The drug release and induced apoptosis of cancer cells expressing both biotin receptors and high levels of NQO1 was simultaneously monitored via the innate fluorescence of the released SN-38 by confocal microscopy. In vitro and in vivo studies showed an effective inhibition of cancer growth by the enzyme-triggered theranostic prodrug 1. Thus, this type of enzyme-triggered targeted prodrug therapy is an interesting and promising approach for future cancer treatment.

A fluorescent probe to detect thiol-containing amino acids in solid tumors

Early detecting of cancer is critical to provide proper treatment and to improve survival of patients. Here, we reported a highly sensitive ratiometric (yellow emission (550 nm) to blue emission (496 nm)) fluorescent probe 1 developed for detection of thiol-containing amino acids. This probe successfully eliminates interference from background autofluorescence, and discriminates between human carcinoma and normal cells by detecting intracellular thiol levels in living cells (P < 0.05). Furthermore, the ability of the probe to identify growing tumors by measuring GSH in the tissues as well as in the fresh blood of tumor xenograft mice. Additionally, the ratio of the emission intensity at two different wavelengths can provide quantitative analysis of glutathione (GSH) in the living systems. It suggests that it represents a promising prognostic and diagnostic marker, with extensive and simple potential clinical applications.

Biological nitrogen and phosphorus removal in UCT-type MBR process.

A lab-scale UCT-type membrane bio-reactor (MBR) was operated for biological nitrogen (N) and phosphorus (P) removal simultaneously. In order to examine biological nutrient removal (BNR) characteristics of MBR, the lab unit was fed with a synthetic strong and weak wastewater. With strong wastewater, a simultaneous removal of N and P was achieved while application of weak wastewater resulted in a decrease of both N and P removal. Recycled nitrate due to the limited organic in weak wastewater operation probably caused a nitrate inhibition in anaerobic zone. In step feed modification with weak wastewater, both N and P removal capability recovered in the system, indicating that the allocation of COD for denitrification at anoxic zone was a key to increase the biological P removal. In addition, the analysis on the specific P uptake rate in anoxic zone demonstrated that denitrifying phosphorus accumulating organism (dPAO) played an important role to remove up to 40% of P along with N. The sludge production characteristics of UCT-type MBR were similar to ordinary activated sludge with BNR capability.

Nanotopography Promotes Pancreatic Differentiation of Human Embryonic Stem Cells and Induced Pluripotent Stem Cells

Although previous studies suggest that nanotopographical features influence properties and behaviors of stem cells, only a few studies have attempted to derive clinically useful somatic cells from human pluripotent stem cells using nanopatterned surfaces. In the present study, we report that polystyrene nanopore-patterned surfaces significantly promote the pancreatic differentiation of human embryonic and induced pluripotent stem cells. We compared different diameters of nanopores and showed that 200 nm nanopore-patterned surfaces highly upregulated the expression of PDX1, a critical transcription factor for pancreatic development, leading to an approximately 3-fold increase in the percentage of differentiating PDX1(+) pancreatic progenitors compared with control flat surfaces. Furthermore, in the presence of biochemical factors, 200 nm nanopore-patterned surfaces profoundly enhanced the derivation of pancreatic endocrine cells producing insulin, glucagon, or somatostatin. We also demonstrate that nanopore-patterned surface-induced upregulation of PDX1 is associated with downregulation of TAZ, suggesting the potential role of TAZ in nanopore-patterned surface-mediated mechanotransduction. Our study suggests that appropriate cytokine treatments combined with nanotopographical stimulation could be a powerful tool for deriving a high purity of desired cells from human pluripotent stem cells.

Valproic acid promotes differentiation of hepatocyte-like cells from whole human umbilical cord-derived mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are mesoderm-derived cells that are considered a good source of somatic cells for treatment of many degenerative diseases. Previous studies have reported the differentiation of mesodermal MSCs into endodermal and ectodermal cell types beyond their embryonic lineages, including hepatocytes and neurons. However, the molecular pathways responsible for the direct or indirect cell type conversion and the functional ability of the differentiated cells remain unclear and need further research. In the present study, we demonstrated that valproic acid (VPA), which is a histone deacetylase inhibitor, induced an increase in the expression of endodermal genes including CXCR4, SOX17, FOXA1, FOXA2, GSC, c-MET, EOMES, and HNF-1β in human umbilical cord derived MSCs (hUCMSCs). In addition, we found that VPA is able to increase these endodermal genes in hUCMSCs by activating signal transduction of AKT and ERK. VPA pretreatment increased hepatic differentiation at the expense of adipogenic differentiation. The effects of VPA on modulating hUCMSCs fate were diminished by blocking AKT and ERK activation using specific signaling inhibitors. Together, our results suggest that VPA contributes to the lineage conversion of hUCMSCs to hepatic cell fate by upregulating the expression of endodermal genes through AKT and ERK activation.

Interleukin-8 is related to poor chemotherapeutic response and tumourigenicity in hepatocellular carcinoma

AIM Interleukin-8 (IL-8) has been suggested as a prognostic biomarker for human hepatocellular carcinoma (HCC), but its roles in HCC progression and drug resistance have not been studied. This study investigates the role and underlying mechanism of IL-8 in the chemoresistance and progressive growth of HCC. METHODS The change of chemosensitivity and proportion of side population in hepatoma cells was examined by cell growth and flow cytometric analyses after anti-cancer treatments or knockdown of IL-8. Expression of IL-8 and ATP-binding cassette (ABC) transporters in hepatoma cells, xenograft and clinical HCC tissues was determined by Western blot and immunohistochemical analyses. Tumourigenicity of hepatoma cells was evaluated in vivo after silencing IL-8 gene. RESULTS Treatment of hepatoma cells with anti-cancer drugs increased the production of IL-8 and its receptor, as well as the proportion of side population (SP). Exogenous IL-8 increased the SP fraction and expression of multidrug resistance-1, decreasing the drug sensitivity. Silencing of IL-8 gene decreased the ratio of SP cells and drug resistance properties. Both IL-8 and ABC transporters were highly expressed in xenograft and clinical HCC tissues, and knockdown of IL-8 significantly reduced tumour size in vivo. CONCLUSION Anti-cancer drug-induced IL-8 secretion increased the expression of ABC transporters and SP cells, promoting the growth of HCC in vitro. Thus IL-8 may be a potential therapeutic target in the treatment of HCC.