VEGF is upregulated in a neuroblastoma and hepatocyte coculture model

Microencapsulation of Neuroblastoma Cells and Mesenchymal Stromal Cells in Collagen Microspheres: A 3D Model for Cancer Cell Niche Study

There is a growing trend for researchers to use in vitro 3D models in cancer studies, as they can better recapitulate the complex in vivo situation. And the fact that the progression and development of tumor are closely associated to its stromal microenvironment has been increasingly recognized. The establishment of such tumor supportive niche is vital in understanding tumor progress and metastasis. The mesenchymal origin of many cells residing in the cancer niche provides the rationale to include MSCs in mimicking the niche in neuroblastoma. Here we co-encapsulate and co-culture NBCs and MSCs in a 3D in vitro model and investigate the morphology, growth kinetics and matrix remodeling in the reconstituted stromal environment. Results showed that the incorporation of MSCs in the model lead to accelerated growth of cancer cells as well as recapitulation of at least partially the tumor microenvironment in vivo. The current study therefore demonstrates the feasibility for the collagen microsphere to act as a 3D in vitro cancer model for various topics in cancer studies.

The effect of hepatic progenitor cells on experimental hepatocellular carcinoma in the regenerating liver

OBJECTIVE

Liver regeneration following hepatectomy can stimulate the growth of hepatocellular carcinoma (HCC), and major hepatectomy can be associated with activation of hepatic progenitor cells (HPCs). The aim of this study was to evaluate how HPCs influence the malignant potential of tumor cells in vitro and HCC tumor growth after surgery in a rodent model.

MATERIAL AND METHODS

Hepatoma cells (JM1) were cultured with conditioned medium (CM) from syngeneic HPCs (WB-F344). Growth rate, resistance to Adriamycin, and expression patterns for invasiveness and stemness were compared with naïve JM1. Microscopic HCC tumors from naïve JM1 or JM1 cultured with CM were inoculated in Fischer 344 rats undergoing 70% hepatectomy with or without simultaneous infusion of WB-F344. Tumor growth and invasiveness-related factors were compared. Buffalo rats were induced with Morris hepatoma cells. Liver tissue from both in vivo models was examined with regard to activation of cells with progenitor-like phenotype.

RESULTS

Co-culture with CM resulted in an increased resistance to Adriamycin and enhanced expressions of α-FP, MMP9, ABCG2, CD133, and SOX2, as well as the activation of ERK, AKT, WNT, and TGF-β1 pathways. Tumor size and metastases were significantly higher in groups with co-cultured cells or HPCs infusion. After 70% hepatectomy and tumor implantation, cells positive for α-FP, CK19, and CD133 were found, thus suggesting a progenitor-like phenotype in the setting of epithelial-mesenchymal transition.

CONCLUSION

HPCs have a marked effect on HCC cells in vitro and appear to stimulate the growth and malignant potential of experimental HCC tumors.

Differentiation of human bone marrow mesenchymal stem cells into bladder cells: potential for urological tissue engineering

Bone marrow mesenchymal stem cells (BMSCs) are capable of differentiating into multiple cell types, providing an alternative cell source for cell-based therapy and tissue engineering. Simultaneous differentiation of human BMSCs into smooth muscle cells (SMCs) and urothelium would be beneficial for clinical applications in bladder regeneration for patients with bladder exstrophy or cancer who need cystoplasty. We investigated the ability of human BMSCs to differentiate toward both SMCs and urothelium with cocultured or conditioned media and analyzed growth factors from a coculture system. After being cocultured with urothelium or cultured using urothelium-derived conditioned medium, human BMSCs expressed urothelium-specific genes and proteins: uroplakin-Ia, cytokeratin-7, and cytokeratin-13. When cocultured with SMCs or cultured in SMC-conditioned medium, human BMSCs expressed SMC-specific genes and proteins: desmin and myosin. Several growth factors (hepatocyte growth factor, platelet-derived growth factor-homodimer polypeptide of B chain (BB), transforming growth factor-beta1, and vascular endothelial growth factor) were detected in the SMC cocultured media and in the urothelium cocultured media (epidermal growth factor, platelet-derived growth factor-BB, transforming growth factor-beta1, and vascular endothelial growth factor). BMSC-scaffold constructs significantly improved cell contractility after myogenic differentiation. In vivo-grafted cells displayed significant matrix infiltration and expressed SMC-specific markers in the nanofibrous poly-l-lactic acid scaffolds. In conclusion, smooth muscle- and urothelium-like cells derived from human BMSCs provide an alternative cell source for potential use in bladder tissue engineering.

Effects of oncostatin M on secretion of vascular endothelial growth factor and reconstruction of liver-like structure by fetal liver cells in monolayer and three-dimensional cultures

Vascular endothelial growth factor (VEGF) is crucial for the development and regeneration of the liver. However, there have been no reports about VEGF secretion by cultured fetal liver cells (FLCs). In the present study, the effects of oncostatin M (OSM), which strongly stimulates the growth and albumin secretion of FLCs, on VEGF secretion and morphological changes of long-term cultured FLCs were investigated under three-dimensional (3-D) and monolayer conditions. The cultured FLCs proliferated well and showed stable secretion of VEGF for up to 1 month under both monolayer and 3-D culture conditions. The addition of OSM to cultured cells strongly enhanced VEGF secretion. Compared with 3-D cultures, VEGF secretion per cell was higher in monolayer cultures. After 1 month in culture, the FLCs in 3-D cultures formed large aggregates like liver tissue, and FLCs also formed colonies and duct-like structures after several months of culture even under monolayer conditions. In conclusion, OSM stimulated the secretion of VEGF by cultured FLCs, which seemed to contribute to the development of a liver-like structure.

Expression of VEGF receptors in cocultured neuroblastoma cells

BACKGROUND

VEGF is best known for its angiogenic properties. We have found that VEGF expression is increased in neuroblastoma cells cocultured with hepatocytes. In addition, we have previously shown that neuroblastoma cells cultured with exogenous VEGF have an increase in the expression of VEGF receptors. Therefore, we hypothesized that the expression of VEGF receptors would be up-regulated in neuroblastoma cells grown in the coculture environment.

MATERIALS AND METHODS

Two neuroblastoma cell lines (IMR-32 or SK-N-DZ) are used. These cells are cultured alone and in a coculture system with hepatocytes. Message for VEGF and the VEGF receptors KDR, flt-1, flt-4, neuropilin 1 (NRP-1), and neuropilin 2 (NRP-2) are measured with RT-PCR. Flt-4, NRP-1, and NRP-2 protein expression is measured with Western blot.

RESULTS

The receptors KDR and flt-1 are not detected in either cell line in either control or coculture conditions. Message for VEGF and flt-4 is significantly increased in the cocultured IMR-32 cells, while that for NRP-1 and NRP-2 is unchanged in these cells. VEGF and its receptors are unchanged in cocultured SK-N-DZ cells.

CONCLUSIONS

Neuroblastoma cells express specific VEGF receptors that are differentially regulated in the different cell lines. These findings suggest that the heterogeneity of neuroblastomas may limit the utility of targeting VEGF and its receptors as sole treatments for the tumor, and that successful therapies will be dependent upon the specific biology of the tumor.

VEGF receptors are differentially expressed by neuroblastoma cells in culture

BACKGROUND/PURPOSE

Vascular endothelial growth factor (VEGF) is best known for its angiogenic properties, but its mitogenic capacity may be more important for tumorigenesis. The ability of VEGF to induce specific biologic activities may be dependent on the amount and type of VEGF receptors present. The authors hypothesize that neuroblastoma cells express specific VEGF receptors and that their expression may be altered when the cells are exposed to differing cytokines and culture environments.

METHODS

Four groups of human neuroblastoma cells (IMR-32) are studied. (1) Control cells: cultured in standard media. (2) VEGF cells: VEGF added to the media. (3) Tumor necrosis factor alpha (TNF-alpha) cells: TNF-alpha added to the media. (4) Serum starved cells: cultured in serum-depleted media. Reverse transcriptase polymerase chain reaction (RT-PCR) is utilized to measure the VEGF receptors flt-1, KDR/flk-1, flt-4, neuropilin 1 (NRP-1), and neuropilin 2 (NRP-2).

RESULTS

Flt-1 and KDR are not detected in any groups. Flt-4, NRP-1, and NRP-2 are present in the IMR-32 cells, and their expression is significantly increased by the administration of VEGF. Neuroblastoma cells cultured with TNF-alpha or in serum-depleted media have a significant decrease in the expression of these receptors.

CONCLUSIONS

The authors show that neuroblastoma cells express specific VEGF receptors that may be altered by mitogenic or apoptotic stimuli. Specifically targeting VEGF and its receptors may be another therapeutic strategy for the treatment of neuroblastoma.

Neuroblastoma, Apoptosis, and Growth Factors

Neuroblastoma is the most common extracranial tumor of childhood. This tumor is associated with alterations in apoptosis and is affected by various growth factors and cytokines. In this short review we will discuss recent findings in our laboratory where we have been studying a cell culture model of neuroblastoma.

Expression of sphingosine kinase gene in the interactions between human gastric carcinoma cell and vascular endothelial cell

AIM: To study the interactions between human gastric carcinoma cell (HGCC) and human vascular endothelial cell (HVEC), and if the expression of sphingosine kinase (SPK) gene was involved in these interactions.

METHODS: The specific inhibitor to SPK, dimethyl sphingosine (DMS), was added acting on HGCC and HVEC, then the cell proliferation was measured by MTT. The conditioned mediums (CMs) of HGCC and HVEC were prepared. The CM of one kind of cell was added to the other kind of cell, and the cell proliferation was measured by MTT. After the action of CM, the cellular expression of SPK gene in mRNA level was detected with in situ hybridization (ISH).

RESULTS: DMS could almost completely inhibit the proliferation of HGCC and HVEC. The growth inhibitory rates could amount to 97.21%, 83.42%, respectively (P < 0.01). The CM of HGCC could stimulate the growth of HVEC (2.70 ± 0.01, P < 0.01) while the CM of HVEC could inhibit the growth of HGCC (52.97% ± 0.01%, P < 0.01). There was no significant change in the mRNA level of SPK gene in one kind of cell after the action of the CM of the other kind of cell.

CONCLUSION: SPK plays a key role in regulating the proliferation of HGCC and HVEC. There exist complicated interactions between HGCC and HVEC. HGCC can significantly stimulate the growth of HVEC while HVEC can significantly inhibit the growth of HGCC. The expression of SPK gene is not involved in the interactions.

The role of KDR in the interactions between human gastric carcinoma cell and vascular endothelial cell

AIM: To study the interactions between human gastric carcinoma cell (HGCC) and human vascular endothelial cell (HVEC), and the role of KDR in these interactions.

METHODS: Antisense oligodexynucleotide (ASODN) specific to KDR gene was devised and added to the culture medium of HGCC and HVEC. After the action of ASODN, the proliferation of two cells was measured by MTT method. The role of KDR in regulating the proliferation of two kinds of cells was known through observing the effect of ASODN on them. The conditioned mediums (CMs) of HGCC and HVEC were prepared. The CM of one kind of cell was added acting on the other kind of cell, then the cell proliferation was measured by MTT. After the action of ASODN or CM, the cellular expression of KDR gene was detected with in situ hybridization (ISH) for mRNA level and with immunohistochemical staining for protein level. ABC-ELISA was used to detect hVEGF in the CMs of two cells.

RESULTS: KDR ASODN could specifically inhibit the proliferation of HGCC and HVEC significantly. The growth inhibitory rate amounted to 55.35% and 54.83%, respectively (P < 0.01). HGCC and HVEC could secret a certain level of hVEGF (92.06 ± 1.69 ng/L, 77.70 ± 8.04 ng/L). The CM of HGCC could significantly stimulate the growth (2.70 ± 0.01 times) and KDR gene expression of HVEC (P < 0.01) while the CM of HVEC could significantly inhibit the growth (52.97% ± 0.01%) and KDR gene expression of HGCC (P < 0.01).

CONCLUSION: KDR plays a key role in regulating the proliferation of HGCC and HVEC. There exist complicated interactions between HGCC and HVEC. HGCC can significantly stimulate the growth of HVEC while HVEC can significantly inhibit the growth of HGCC. KDR is involved in the interactions between them.

Caspase 3 expression is altered in a coculture model of neuroblastoma

BACKGROUND

Previously, we demonstrated that neuroblastoma cells cocultured with hepatocytes are protected from apoptosis, while apoptosis is upregulated in the hepatocytes. The mechanisms responsible for these findings are unknown. We hypothesize that caspase 3, a cysteine protease central to the apoptotic pathway, will be altered in this coculture model that simulates metastatic neuroblastoma.

METHODS

Control human neuroblastoma cells and liver cells are plated in standard media. For the study group, a noncontact, coculture system is used. Hepatocytes are plated on cell culture inserts, placed above a growing layer of neuroblastoma cells, and incubated. Activated caspase 3 is measured after 1, 2, 3, or 4 days.

RESULTS

Activated caspase 3 levels are significantly decreased in the cocultured neuroblastoma cells on days 2, 3, and 4. Conversely, cocultured hepatocytes have a significant increase in caspase 3 activation at all time periods, with the largest difference seen after 1 day in coculture.

CONCLUSIONS

The capacity for neuroblastoma to differentially alter caspase 3 activation may provide a significant survival advantage for the neuroblastoma cells in metastatic environments. Understanding the mechanisms for this altered regulation may lead to improved and better targeted therapy for this malignancy.