[Show abstract][Hide abstract] ABSTRACT: The tumor tropism of mesenchymal stem cells (MSCs) makes them an excellent delivery vehicle used in anticancer therapy. However, the exact mechanisms of MSCs involved in tumor microenvironment are still not well defined. Molecular imaging technologies with the versatility in monitoring the therapeutic effects, as well as basic molecular and cellular processes in real time, offer tangible options to better guide MSCs mediated cancer therapy. In this study, an in situ breast cancer model was developed with MDA-MB-231 cells carrying a reporter system encoding a double fusion (DF) reporter gene consisting of firefly luciferase (Fluc) and enhanced green fluorescent protein (eGFP). In mice breast cancer model, we injected human umbilical cord-derived MSCs (hUC-MSCs) armed with a triple fusion (TF) gene containing the herpes simplex virus truncated thymidine kinase (HSV-ttk), renilla luciferase (Rluc) and red fluorescent protein (RFP) into tumor on day 13, 18, 23 after MDA-MB-231 cells injection. Bioluminescence imaging of Fluc and Rluc provided the real time monitor of tumor cells and hUC-MSCs simultaneously. We found that tumors were significantly inhibited by hUC-MSCs administration, and this effect was enhanced by ganciclovir (GCV) application. To further demonstrate the effect of hUC-MSCs on tumor cells in vivo, we employed the near infrared (NIR) imaging and the results showed that hUC-MSCs could inhibit tumor angiogenesis and increased apoptosis to a certain degree. In conclusion, hUC-MSCs can inhibit breast cancer progression by inducing tumor cell death and suppressing angiogenesis. Moreover, molecular imaging is an invaluable tool in tracking cell delivery and tumor response to hUC-MSCs therapies as well as cellular and molecular processes in tumor.
[Show abstract][Hide abstract] ABSTRACT: Oncogene-induced senescence is a stable proliferative arrest that serves as a tumor-suppressing defense mechanism. p38 MAPK has been implicated in oncogene-induced senescence and tumor suppression. However, the specific role of each of the four p38 isoforms in oncogene-induced senescence is not fully understood. Here, we demonstrate that p38δ mediates oncogene-induced senescence through a p53- and p16(INK4A)-independent mechanism. Instead, evidence suggests a link between p38δ and the DNA damage pathways. Moreover, we have discovered a novel mechanism that enhances the expression of p38δ during senescence. In this mechanism, oncogenic ras induces the Raf-1-MEK-ERK pathway, which in turn activates the AP-1 and Ets transcription factors that are bound to the p38δ promoter, leading to increase transcription of p38δ. These findings indicate that induction of the pro-senescent function of p38δ by oncogenic ras is achieved through 2 mechanisms, transcriptional activation by the Raf-1-MEK-ERK-AP-1/Ets pathway, which increases the cellular concentration of the p38δ protein, and posttranslational modification by MKK3/6, which stimulates the enzymatic activity of p38δ. In addition, these studies identify the AP-1 and Ets transcription factors as novel signaling components in the senescence-inducing pathway.
Molecular and cellular biology 07/2013; · 6.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Myocardial infarction is a leading cause of mortality and morbidity worldwide, and current treatments fail to address the underlying scarring and cell loss, which is a major cause of heart failure after infarction. The novel strategy, therapeutic angiogenesis and/or vasculogenesis with endothelial progenitor cells transplantation holds great promise to increase blood flow in ischemic areas, thus rebuild the injured heart and reverse the heart failure. Given the potential of self-renewal and differentiation into virtually all cell types, human embryonic stem cells (hESCs) may provide an alternate source of therapeutic cells by allowing the derivation of large numbers of endothelial cells for therapeutic angiogenesis and/or vasculogenesis of ischemic heart diseases. Moreover, to fully understand the fate of implanted hESCs or hESC derivatives, investigators need to monitor the motility of cells in living animals over time. In this chapter, we describe the application of bioluminescence reporter gene imaging to track the transplanted hESC-derived endothelial cells for treatment of myocardial infarction. The technology of inducing endothelial cells from hESCs will also be discussed.
[Show abstract][Hide abstract] ABSTRACT: Endothelial progenitor cells (EPCs) have shown tropism towards primary tumors or metastases and are thus potential vehicles for targeting tumor therapy. However, the source of adult EPCs is limited, which highlights the need for a consistent and renewable source of endothelial cells for clinical applications. Here, we investigated the potential of human embryonic stem cell-derived endothelial cells (hESC-ECs) as cellular delivery vehicles for therapy of metastatic breast cancer. In order to provide an initial assessment of the therapeutic potency of hESC-ECs, we treated human breast cancer MDA-MB-231 cells with hESC-ECs condition medium (EC-CM) in vitro. The results showed that hESC-ECs could suppress the Wnt/β-catenin signaling pathway and thereby inhibit the proliferation and migration of MDAMB-231 cells. To track and evaluate the possibility of hESC-EC-employed therapy, we employed the bioluminescence imaging (BLI) technology. To study the therapeutic potential of hESC-ECs, we established lung metastasis models by intravenous injection of MDA-MB-231 cells labeled with firefly luciferase (Fluc) and green fluorescent protein (GFP) to NOD/SCID mice. In mice with lung metastases, we injected hESC-ECs armed with herpes simplex virus truncated thymidine kinase (HSV-ttk) intravenously on day 11, 16, 21, and 26 after MDA-MB-231 cell injection. The NOD/SCID mice were subsequently treated with ganciclovir (GCV) and the growth status of tumor was monitored by Fluc imaging. We found that MDA-MB-231 tumors were significantly inhibited by intravenously injected hESC-ECs. The tumor-suppressive effects of the hESC-ECs, by inhibiting Wnt/β-catenin signaling pathway and inducing tumor cell death through bystander effect in human metastatic breast cancer model, provide previously unexplored therapeutic modalities for cancer treatment.
[Show abstract][Hide abstract] ABSTRACT: The inadequate treatment efficacy, suboptimal cancer detection and disease monitoring in anticancer therapies have led to the quest for clinically relevant, innovative multifaceted solutions such as development of targeted and traceable approaches. Molecular imaging technologies with the versatility of liposomal nanoparticles platform offer tangible options to better guide treatment delivery and monitor outcome. In this study, we introduced noninvasive, quantitative and functional imaging techniques with reporter gene methods to probe breast cancer processes with liposomal nanoparticles by bioluminescence imaging (BLI). A breast cancer model was applied for therapy by injecting 5.0 x 10(5) 4T1 cells carrying a reporter system encoding a double fusion reporter gene consisting of firefly luciferase (Fluc) and green fluorescent protein (GFP) into BALB/c mice. Liposomal nanoparticles loaded with a triple fusion gene containing the herpes simplex virus truncated thymidine kinase (HSV-ttk) and renilla luciferase (Rluc) and red fluorescent protein (RFP) were applied by in situ injection for monitoring and evaluating gene therapy. The BALB/c mice were subsequently treated with ganciclovir (GCV) and the growth status of tumor was monitored by bioluminescence imaging of Fluc and the treatment delivery of liposomal nanoparticle was efficiently tracked by Rluc imaging. In fact, TF plasmids were shown to be useful for monitoring and evaluating targeting efficacy and gene therapy by non-invasive molecular imaging. In conclusion, the combination of noninvasive imaging techniques and liposomal nanoparticle can provide a practical and clinically useful way for gene delivery and monitoring the level of gene expression over time and treatment response in patients undergoing gene therapy.
Journal of Biomedical Nanotechnology 10/2012; 8(5):742-50. · 7.58 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Most hepatocellular carcinoma (HCC) therapies fail to target cancer stem cells (CSCs) and monitor cancer progression or regression. The purpose of this study was to evaluate the possibility of cancer imaging and simultaneously monitoring targeted therapy in a single animal by anti-CD44 antibody-mediated liposomal nanoparticle. In this study, an in situ liver tumor model was applied for therapy by injecting 1.0 × 10(6) HepG2 cells carrying a reporter system encoding a double fusion (DF) reporter gene consisting of firefly luciferase (Fluc) and green fluorescent protein (GFP) into the liver of NOD/SCID mice. A strategy was developed which specifically targeted HCC via anti-CD44 antibody-mediated liposomal nanoparticle delivery, loaded of either doxorubicin (Dox) or a triple fusion (TF) gene containing the herpes simplex virus truncated thymidine kinase (HSV-ttk) and renilla luciferase (Rluc) and red fluorescent protein (RFP). The NOD/SCID mice were subsequently treated with ganciclovir (GCV) and the growth status of tumor was monitored by optical bioluminescence imaging (BLI) of Fluc and specific targeting of the liposomal nanoparticle was tracked by Rluc imaging. CD44 antibody-mediated liposomal nanoparticle, loaded of TF plasmids, were shown to be useful for monitoring and evaluating targeting efficacy and gene therapy by non-invasive molecular imaging. Here, we demonstrate the time intensive preclinical steps involved in molecular target identification, validation, and characterization by dual molecular imaging. This targeted and traceable therapeutic strategy has potential advantages to overcome the problems of conventional tumor therapy and may open a new application for the treatment of HCC by targeting CSCs.
[Show abstract][Hide abstract] ABSTRACT: Legumain is a member of the asparaginyl endopeptidase family that is over-expressed in response to hypoxic stress on mammary adenocarcinoma, colorectal cancer, proliferating endothelial cells, and tumor-associated macrophages (TAMs). Here, we demonstrate that elevated expression of legumain in ovarian cancer by a proteomic approach using isobaric tags for relative and absolute quantification (iTRAQ) followed by liquid chromatography-mass spectrometry (LC-MS/MS). To investigate the relationship between legumain expression and ovarian cancer development, we tested legumain expression in malignant human ovarian tumors (n = 60), borderline ovarian tumors (n = 20), benign ovarian tumors (n = 20), and normal ovary samples (n = 20) using immunohistochemical assay (IHC). A correlation between legumain expression, and clinocopathologic and biological variables was also established. Importantly, increased legumain expression was validated by real-time PCR and Western blots, correlated positively with an increased malignancy of ovarian tumors (P < 0.01). In fact, patients with strong legumain expression had a worse prognosis (P = 0.03). In addition, results of in vitro experiments revealed that over-expression of legumain correlates with increased cell migration and invasion of ovarian cancer cells. Although legumain's functional role and clinical utility remain to be established, our results indicated that a sensitive assay for early expression of legumain may serve as both a potential biomarker and a molecular target for treatment of ovarian cancer.
Journal of Cellular Biochemistry 03/2012; 113(8):2679-86. · 3.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Human embryonic stem (hES) cells have a potential use for the repair and regeneration of injured tissues. However, teratoma formation can be a major obstacle for hES-mediated cell therapy. Therefore, tracking the fate and function of transplanted hES cells with noninvasive imaging could be valuable for a better understanding of the biology and physiology of teratoma formation. In this study, hES cells were stably transduced with a double fusion reporter gene consisting of firefly luciferase and enhanced green fluorescent protein. Following bioluminescence imaging and histology, we demonstrated that engraftment of hES cells was followed by dramatically increasing signaling and led to teratoma formation confirmed by histology. Studies of the angiogenic processes within teratomas revealed that their vasculatures were derived from both differentiated hES cells and host. Moreover, FACS analysis showed that teratoma cells derived from hES cells expressed high levels of CD56 and SSEA-4, and the subcultured SSEA-4(+) cells showed a similar cell surface marker expression pattern when compared to undifferentiated hES cells. We report here for the first time that SSEA-4(+) cells derived from teratoma exhibited multipotency, retained their differentiation ability in vivo as confirmed by their differentiation into representative three germ layers.
Journal of Cellular Biochemistry 03/2011; 112(3):840-8. · 3.06 Impact Factor