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author:("Pyle, maria M")
1.  Naïve rat umbilical cord matrix stem cells significantly attenuate mammary tumor growth through modulation of endogenous immune responses 
Cytotherapy  2013;15(5):586-597.
Background aims
Un-engineered human and rat umbilical cord matrix stem cells (UCMSCs) attenuate growth of several types of tumors in mice and rats. However, the mechanism by which UCMSCs attenuate tumor growth has not been studied rigorously.
The possible mechanisms of tumor growth attenuation by rat UCMSCs were studied using orthotopic Mat B III rat mammary tumor grafts in female F344 rats. Tumor-infiltrating leukocytes were identified and quantified by immunohistochemistry analysis. Potential cytokines involved in lymphocyte infiltration in the tumors were determined by microarray and Western blot analysis. The Boyden chamber migration assay was performed for the functional analysis of identified cytokines.
Rat UCMSCs markedly attenuated tumor growth; this attenuation was accompanied by considerable lymphocyte infiltration. Immunohistochemistry analysis revealed that most infiltrating lymphocytes in the rat UCMSC-treated tumors were CD3+ T cells. In addition, treatment with rat UCMSCs significantly increased infiltration of CD8+ and CD4+ T cells and natural killer (NK) cells throughout tumor tissue. CD68+ monocytes/macrophages and Foxp3+ regulatory T cells were scarcely observed, only in the tumors of the phosphate-buffered saline control group. Microarray analysis of rat UCMSCs demonstrated that monocyte chemotactic protein-1 is involved in rat UCMSC-induced lymphocyte infiltration in the tumor tissues.
These results suggest that naïve rat UCMSCs attenuated mammary tumor growth at least in part by enhancing host anti-tumor immune responses. Naïve UCMSCs can be used as powerful therapeutic cells for breast cancer treatment, and monocyte chemotactic protein-1 may be a key molecule to enhance the effect of UCMSCs at the tumor site.
PMCID: PMC3652627  PMID: 23474329
immune response; macrophages; mammary tumor; rat umbilical cord matrix stem cells; T cells
2.  A Cell-Delivered and –Activated SN38-Dextran Prodrug Increases Survival in a Murine Disseminated Pancreatic Cancer Model 
Enzyme activated prodrugs have been investigated and sought after as highly specific, low side effect treatments, especially for cancer therapy. Unfortunately, excellent targets for enzyme activated therapy are rare. Here we demonstrate a system based on cell delivery that can carry both a prodrug and an activating enzyme to the cancer site. Raw264.7 cells (mouse monocyte/macrophage like cells, Mo/Ma) were engineered to express intracellular rabbit carboxylesterase (InCE), which is a potent activator of the prodrug irinotecan to SN38. InCE expression was regulated by the TetOn® system, which silences the gene unless a tetracycline, such as doxycycline, is present. Concurrently, an irinotecan-like prodrug, conjugated to dextran, was synthesized that could be loaded into the cytoplasm of Mo/Ma. To test the system, a murine pancreatic cancer model was generated by intraperitoneal (i.p.) injection of Pan02 cells. Engineered Mo/Ma were loaded with the prodrug and were injected i.p. Two days later, doxycycline was given i.p. to activate InCE, which activated the prodrug. A survival study demonstrated that this system significantly increased survival in a murine pancreatic cancer model. Thus, for the first time, a prodrug/activating enzyme system self-contained within tumor-homing cells has been demonstrated that can prolong the life of i.p. pancreatic tumor bearing mice.
PMCID: PMC3583224  PMID: 22238072
Prodrug Therapy; Cytotherapy; Pancreatic Cancer; Cancer Targeting
3.  Identification and characterization of unique tumoricidal genes in rat umbilical cord matrix stem cells 
Molecular pharmaceutics  2011;8(5):1549-1558.
Rat umbilical cord matrix stem cells (UCMSC) have been shown to exhibit a remarkable ability to control rat mammary adenocarcinoma (Mat B III) cell proliferation both in vivo and in vitro. To study the underlying mechanisms and genes involved in Mat B III growth attenuation, total RNA was extracted from the naïve rat UCMSC alone and those co-cultured with Mat B III in Transwell culture dishes. Gene expression profiles of naive rat UCMSC alone and those co-cultured with Mat B III cells were investigated by microarray analysis using an Illumina RatRef-12 Expression BeadChip. The comparison of gene expression profiles between untreated and co-cultured rat UCMSC identified five up-regulated candidate genes (follistatin (FST), sulfatase1 (SULF-1), glucose phosphate isomerase (GPI), HtrA serine peptidase (HTRA1), and adipocyte differentiation-related protein (ADRP)) and two down-regulated candidate genes (transforming growth factor, beta-induced, 68kDa (TGFβI) and podoplanin (PDPN)) based upon the following screening criteria: 1) expression of the candidate genes should show at least a 1.5 fold change in rat UCMSC co-cultured with Mat B III cells; 2) candidate genes encode secretory proteins; and 3) they encode cell growth-related proteins. Following confirmation of gene expression by real time-PCR, ADRP, SULF-1 and GPI were selected for further analysis. Addition of specific neutralizing antibodies against these three gene products individually in co-cultures of 1:20 rat UCMSC:Mat B III cells significantly increased cell proliferation, implying that these gene products are produced under the co-cultured condition and functionally attenuate cell growth. Immunoprecipitation followed by Western blot analysis demonstrated that these proteins are indeed secreted into the culture medium. Individual over-expression of these three genes in rat UCMSC significantly enhanced UCMSC-dependent inhibition of cell proliferation in co-culture. These results suggest that ADRP, SULF-1 and GPI act as tumor suppressor genes, and these genes might be involved in rat UCMSC-dependent growth attenuation of rat mammary tumors.
PMCID: PMC3202613  PMID: 21851062
Rat umbilical cord matrix stem cells; Rat mammary tumor cells; Mat B III; Microarray; Real time PCR; Thymidine uptake; Tumor suppressor genes; ADRP; GPI; SULF-1
4.  Magnetic-Fe/Fe3O4-nanoparticle-bound SN38 as carboxylesterase-cleavable prodrug for the delivery to tumors within monocytes/macrophages 
The targeted delivery of therapeutics to the tumor site is highly desirable in cancer treatment, because it is capable of minimizing collateral damage. Herein, we report the synthesis of a nanoplatform, which is composed of a 15 ± 1 nm diameter core/shell Fe/Fe3O4 magnetic nanoparticles (MNPs) and the topoisomerase I blocker SN38 bound to the surface of the MNPs via a carboxylesterase cleavable linker. This nanoplatform demonstrated high heating ability (SAR = 522 ± 40 W/g) in an AC-magnetic field. For the purpose of targeted delivery, this nanoplatform was loaded into tumor-homing double-stable RAW264.7 cells (mouse monocyte/macrophage-like cells (Mo/Ma)), which have been engineered to express intracellular carboxylesterase (InCE) upon addition of doxycycline by a Tet-On Advanced system. The nanoplatform was taken up efficiently by these tumor-homing cells. They showed low toxicity even at high nanoplatform concentration. SN38 was released successfully by switching on the Tet-On Advanced system. We have demonstrated that this nanoplatform can be potentially used for thermochemotherapy. We will be able to achieve the following goals: (1) Specifically deliver the SN38 prodrug and magnetic nanoparticles to the cancer site as the payload of tumor-homing double-stable RAW264.7 cells; (2) Release of chemotherapeutic SN38 at the cancer site by means of the self-containing Tet-On Advanced system; (3) Provide localized magnetic hyperthermia to enhance the cancer treatment, both by killing cancer cells through magnetic heating and by activating the immune system.
PMCID: PMC3388369  PMID: 23016149
cell-based delivery; chemotherapeutic prodrug; magnetic Fe/Fe3O4 nanoparticles; SN38
5.  Human Xenografts Are Not Rejected in a Naturally Occurring Immunodeficient Porcine Line: A Human Tumor Model in Pigs 
BioResearch Open Access  2012;1(2):63-68.
Animal models for cancer therapy are invaluable for preclinical testing of potential cancer treatments; however, therapies tested in such models often fail to translate into clinical settings. Therefore, a better preclinical model for cancer treatment testing is needed. Here we demonstrate that an immunodeficient line of pigs can host and support the growth of xenografted human tumors and has the potential to be an effective animal model for cancer therapy. Wild-type and immunodeficient pigs were injected subcutaneously in the left ear with human melanoma cells (A375SM cells) and in the right ear with human pancreatic carcinoma cells (PANC-1). All immunodeficient pigs developed tumors that were verified by histology and immunohistochemistry. Nonaffected littermates did not develop tumors. Immunodeficient pigs, which do not reject xenografted human tumors, have the potential to become an extremely useful animal model for cancer therapy because of their similarity in size, anatomy, and physiology to humans.
PMCID: PMC3559234  PMID: 23514746
immunodeficient swine; large-animal cancer model; melanoma; pancreatic carcinoma; xenografts
6.  Human umbilical cord matrix–derived stem cells expressing interferon-β gene significantly attenuate bronchioloalveolar carcinoma xenografts in SCID mice 
Mesenchymal stem cells derived from the human umbilical cord matrix (hUCMSCs) have great potential for therapeutic use for multiple diseases. The strategy that uses therapeutic gene-transfected hUCMSCs as cellular vehicles for targeted biologic agent delivery has solved the problem of short half life or excessive toxicity of biological agent(s) in vivo. Interferon-β (IFN-β) has demonstrated a potent anti-tumor effect on many types of cancer cell lines in vitro. The aim of this study was to determine the anti-cancer effect of IFN-β gene-transfected hUCMSCs (IFN-β-hUCMSCs) on cells derived from bronchioloalveolar carcinoma, a subset of lung adenocarcinoma that is difficult to treat. The co-culture of a small number of IFN-β-hUCMSCs with the human bronchioloalveolar carcinoma cell lines H358 or SW1573 significantly inhibited growth of both types of carcinoma cell lines. The culture medium conditioned by these cells also significantly attenuated the growth of both carcinoma cells, but this attenuation was abolished by adding anti-IFN-β antibody. Finally, systemic administration of IFN-β-hUCMSCs through the tail vein markedly attenuated growth of orthotopic H358 bronchioloalveolar carcinoma xenografts in SCID mice by increasing apoptosis. These results clearly indicate that IFN-β-hUCMSCs caused cell death of bronchioloalveolar carcinoma cells through IFN-β production, thereby attenuating tumor growth in vivo. These results indicate that IFN-β-hUCMSCs are a powerful anti-cancer cytotherapeutic tool for bronchioloalveolar carcinoma.
PMCID: PMC2930041  PMID: 20138387
bronchioloalveolar carcinoma; H358 cells; SW1573 cells; Interferon-β; stem cell therapy; umbilical cord matrix-derived stem cells; xenografts; SCID mice
7.  Cytotherapy with naïve rat umbilical cord matrix stem cells significantly attenuates growth of murine pancreatic cancer cells and increases mouse survival in syngeneic mice 
Cytotherapy  2010;12(3):408-417.
Pancreatic cancer, sometimes called a “silent killer,” is one of the most aggressive human malignancies, with a very poor prognosis. It is the fourth leading cause of cancer-related morbidity and mortality in the United States.
A mouse peritoneal model was used to test the ability of un-engineered rat umbilical cord matrix derived stem cells (UCMSCs) to control growth of pancreatic cancer. In vivo results are supported by various in vitro assays such as MTT, direct cell count, [3H] thymidine uptake, and soft agar colony assays.
Co-culture of rat UCMSCs with PAN02 murine pancreatic carcinoma cells (UCMSCs:PAN02, 1:6 and 1:3) caused G0/G1 arrest and significantly attenuated the proliferation of PAN02 tumor cells as monitored by MTT assay, direct cell counts, and [3H] thymidine uptake assay. Rat UCMSCs also significantly reduced PAN02 colony size and number as measured by soft agar colony assay. The in vivo mouse studies showed that rat UCMSCs treatment significantly decreased the peritoneal PAN02 tumor burden 3 weeks after tumor transplantation and increased mouse survival time. Histological study revealed that intraperitoneally administered rat UCMSCs survived for at least 3 weeks, and the majority were found near or inside the tumor.
These results indicate that naïve rat UCMSCs alone remarkably attenuate the growth of pancreatic carcinoma cells in vitro and in a mouse peritoneal model. Thus, these studies imply that UCMSCs could be a potential tool for targeted cytotherapy for pancreatic cancer.
PMCID: PMC2896419  PMID: 20345214
Colony assay; cytotherapy; pancreatic cancer; PAN02 cells; rat umbilical cord matrix stem cells; xenografts
8.  Therapy with un-engineered naïve rat umbilical cord matrix stem cells markedly inhibits growth of murine lung adenocarcinoma 
BMC Cancer  2010;10:590.
Lung cancer remains the leading cause of cancer-related mortality despite continuous efforts to find effective treatments. Data from the American Cancer Society indicate that while the overall incidence of lung cancer is declining, it continues to rise in women. Stem cell-based therapy has been an emerging strategy to treat various diseases. The purpose of this paper is to determine the efficacy of an intrinsic anti-cancer effect of rat umbilical cord matrix stem cells (UCMSCs) on lung cancer.
A mouse syngeneic lung carcinoma model was used to test the basic ability of UCMSCs to control the growth of lung cancer. Lung tumors were experimentally induced by tail vein administration of Lewis lung carcinoma (LLC) cells derived from the lung of C57BL/6 mouse. Rat UCMSCs were then administered intratracheally five days later or intravenously on days 5 and 7. The tumor burdens were determined by measuring lung weight three weeks after the treatment.
Co-culture of rat UCMSCs with LLC significantly attenuated the proliferation of LLC cells as monitored by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), a tetrazole cell proliferation assay, thymidine uptake, and direct cell counts. In vitro colony assays with rat UCMSCs as feeder layers markedly reduced LLC colony size and number. Co-culture of rat UCMSCs with LLCs causes G0/G1 arrest of cancer cells. This is evident in the decrease of cyclin A and CDK2 expression. The in vivo studies showed that rat UCMSC treatment significantly decreased tumor weight and the total tumor mass. Histological study revealed that intratracheally or systemically administered rat UCMSCs homed to tumor areas and survived for at least 3 weeks without any evidence of differentiation or adverse effects.
These results indicate that rat UCMSCs alone remarkably attenuate the growth of lung carcinoma cells in vitro and in a mouse syngeneic lung carcinoma graft model and could be used for targeted cytotherapy for lung cancer.
PMCID: PMC2988749  PMID: 21029413
9.  Naïve human umbilical cord matrix derived stem cells significantly attenuate growth of human breast cancer cells in vitro and in vivo 
Cancer letters  2009;280(1):31-37.
The effect of un-engineered (naïve) human umbilical cord matrix stem cells (hUCMSC) on the metastatic growth of MDA 231 xenografts in SCID mouse lung was examined. Three weekly IV injections of 5 × 105 hUCMSC significantly attenuated MDA 231 tumor growth as compared to the saline-injected control. IV injected hUCMSC were detected only within tumors or in close proximity to the tumors. This in vivo result was corroborated by multiple in vitro studies such as colony assay in soft agar and [3H]-thymidine uptake. These results suggest that naïve hUCMSC may be a useful tool for cancer cytotherapy.
PMCID: PMC2914472  PMID: 19285791
human umbilical cord matrix stem cells; breast cancer; MDA 231 cells; xenografts; colony assay

Results 1-9 (9)