Microencapsulation of Engineered Cells to Deliver Sustained High Circulating Levels of Interleukin-6 to Study Hepatocellular Carcinoma Progression

Anti-Inflammatory Effects of Encapsulated Human Mesenchymal Stromal/Stem Cells and a Method to Scale-Up Cell Encapsulation

Mesenchymal stem/stromal cells (MSC) promote recovery in a wide range of animal models of injury and disease. They can act in vivo by differentiating and integrating into tissues, secreting factors that promote cell growth and control inflammation, and interacting directly with host effector cells. We focus here on MSC secreted factors by encapsulating the cells in alginate microspheres, which restrict cells from migrating out while allowing diffusion of factors including cytokines across the capsules. One week after intrathecal lumbar injection of human bone marrow MSC encapsulated in alginate (eMSC), rat IL-10 expression was upregulated in distant rat spinal cord injury sites. Detection of human IL-10 protein in rostrally derived cerebrospinal fluid (CSF) indicated distribution of this human MSC-secreted cytokine throughout rat spinal cord CSF. Intraperitoneal (IP) injection of eMSC in a rat model for endotoxemia reduced serum levels of inflammatory cytokines within 5 h. Detection of human IL-6 in sera after injection of human eMSC indicates rapid systemic distribution of this human MSC-secreted cytokine. Despite proof of concept for eMSC in various disorders using animal models, translation of encapsulation technology has not been feasible primarily because methods for scale-up are not available. To scale-up production of eMSC, we developed a rapid, semi-continuous, capsule collection system coupled to an electrosprayer. This system can produce doses of encapsulated cells sufficient for use in clinical translation.

Polymer microcapsules and microbeads as cell carriers for in vivo biomedical applications

Polymer microcarriers are being extensively explored as cell delivery vehicles in cell-based therapies and hybrid tissue and organ engineering. Spherical microcarriers are of particular interest due to easy fabrication and injectability. They include microbeads, composed of a porous matrix, and microcapsules, where matrix core is additionally covered with a semipermeable membrane. Microcarriers provide cell containment at implantation site and protect the cells from host immunoresponse, degradation and shear stress. Immobilized cells may be genetically altered to release a specific therapeutic product directly at the target site, eliminating side effects of systemic therapies. Cell microcarriers need to fulfil a number of extremely high standards regarding their biocompatibility, cytocompatibility, immunoisolating capacity, transport, mechanical and chemical properties. To obtain cell microcarriers of specified parameters, a wide variety of polymers, both natural and synthetic, and immobilization methods can be applied. Yet so far, only a few approaches based on cell-laden microcarriers have reached clinical trials. The main issue that still impedes progress of these systems towards clinical application is limited cell survival in vivo. Herein, we review polymer biomaterials and methods used for fabrication of cell microcarriers for in vivo biomedical applications. We describe their key limitations and modifications aiming at improvement of microcarrier in vivo performance. We also present the main applications of polymer cell microcarriers in regenerative medicine, pancreatic islet and hepatocyte transplantation and in the treatment of cancer. Lastly, we outline the main challenges in cell microimmobilization for biomedical purposes, the strategies to overcome these issues and potential future improvements in this area.

Release characteristics of cellulose sulphate capsules and production of cytokines from encapsulated cells

The size and speed of release of proteins of different sizes from standard cellulose sulphate capsules (Cell-in-a-Box®) was investigated. Proteins with molecular weights of up to around 70kD can be released. The conformation, charge and concentration of the protein being released play a role in the release kinetics. Small proteins such as cytokines can be easily released. The ability to produce cytokines at a sustained and predefined level from encapsulated cells genetically engineered to overexpress such cytokines and implanted into patients may aid immunotherapies of cancer as well as infectious and other diseases. It will also allow allogeneic rather than autologous cells to be used. We show that cells encapsulated in polymers of cellulose sulphate are able to release cytokines such as interleukin-2 (IL-2) in a stimulated fashion e.g. using phorbol 12-myristate 13-acetate (PMA) plus ionomycin. Given the excellent documented safety record of cellulose sulphate in patients, these data suggest that clinical usage of the technology may be warranted for cancer treatment and other diseases.

A silica-calcium-phosphate nanocomposite drug delivery system for the treatment of hepatocellular carcinoma: in vivo study

Hepatocellular carcinoma (HCC) is notoriously difficult to treat with systemic chemotherapy. The aim of this study was to evaluate a silica-calcium-phosphate nanocomposite (SCPC75) drug delivery system (DDS) as a means to localize cisplatin treatment within the tumor, while reducing systemic toxicity, in a rat model of HCC. The SCPC75 was prepared and loaded with cisplatin and Fourier transform infrared analyses demonstrated even drug distribution within the SCPC75. A rat model of subcutaneous HCC formation was established and animals treated by either systemic cisplatin injection (sCis) or with SCPC75-Cis hybrid placed adjacent (ADJ) to or within (IT) the tumor. Five days after implantation, 50-55% of the total cisplatin loaded had been released from the SCPC75-Cis hybrids resulting in an approximately 50% decrease in tumor volume compared with sCis treatment. sCis-treated animals exhibited severe side effects, including rapid weight loss and decreased liver and kidney function, effects not observed in SCPC75-Cis-treated animals. Analysis of cisplatin distribution demonstrated drug concentrations in the tumor were 21 and 1.5 times higher in IT and ADJ groups, respectively, compared with sCis-treated animals. These data demonstrate the SCPC75 DDS can provide an effective, localized treatment for HCC with significantly reduced toxicity when compared with systemic drug administration.

Therapeutic applications of encapsulated cells

The synergy of some promising advances in the fields of cell therapy and biomaterials together with improvements in the fabrication of more refined and tailored microcapsules for drug delivery have triggered the progress of cell encapsulation technology. Cell microencapsulation involves immobilizing the transplanted cells within a biocompatible scaffold surrounded by a membrane in attempt to isolate the cells from the host immune attack and enhance or prolong their function in vivo. This technology represents one strategy which aims to overcome the present difficulties related to local and systemic controlled release of drugs and growth factors as well as to organ graft rejection and thus the requirements for use of immunomodulatory protocols or immunosuppressive drugs. This chapter gives an overview of the current situation of cell encapsulation technology as a controlled drug delivery system, and the essential requirements of the technology, some of the therapeutic applications, the challenges, and the future directions under investigation are highlighted.

Microencapsulation for the Therapeutic Delivery of Drugs, Live Mammalian and Bacterial Cells, and Other Biopharmaceutics: Current Status and Future Directions

Microencapsulation is a technology that has shown significant promise in biotherapeutics, and other applications. It has been proven useful in the immobilization of drugs, live mammalian and bacterial cells and other cells, and other biopharmaceutics molecules, as it can provide material structuration, protection of the enclosed product, and controlled release of the encapsulated contents, all of which can ensure efficient and safe therapeutic effects. This paper is a comprehensive review of microencapsulation and its latest developments in the field. It provides a comprehensive overview of the technology and primary goals of microencapsulation and discusses various processes and techniques involved in microencapsulation including physical, chemical, physicochemical, and other methods involved. It also summarizes the state-of-the-art successes of microencapsulation, specifically with regard to the encapsulation of microorganisms, mammalian cells, drugs, and other biopharmaceutics in various diseases. The limitations and future directions of microencapsulation technologies are also discussed.

Is surgical resection superior to transplantation in the treatment of hepatocellular carcinoma?

OBJECTIVE

To compare outcomes for patients with hepatocellular carcinoma (HCC) treated with either liver resection or transplantation.

METHODS

A retrospective, single-institution analysis of 413 HCC patients from 1999 to 2009.

RESULTS

A total of 413 patients with HCC underwent surgical resection (n = 106) and transplantation (n = 270) or were listed without receiving transplantation (n = 37). Excluding transplanted patients with incidental tumors (n = 50), 257 patients with suspected HCC were listed with the intent to transplant (ITT). The median diameter of the largest tumor by radiography was 6.0 cm in resected, 3.0 cm in transplanted, and 3.4 cm in the listed-but-not-transplanted patients. Median time to transplant was 48 days. Recurrence rates were 19.8% for resection and 12.1% for all ITT patients. Overall, patient survival for resection versus ITT patients was similar (5-year survival of 53.0% vs 52.0%, not significant). However, for HCC patients with model end-stage liver disease (MELD) scores less than 10 and who radiologically met Milan or UCSF (University of California, San Francisco) criteria, 1-year and 5-year survival rates were significantly improved in resected patients. For patients with MELD score less than 10 and who met Milan criteria, 1-year and 5-year survival were 92.0% and 63.0% for resection (n = 26) versus 83.0% and 41.0% for ITT (n = 73, P = 0.036). For those with MELD score less than 10 and met UCSF criteria, 1-year and 5-year survival was 94.0% and 62.0% for resection (n = 33) versus 81.0% and 40.0% for ITT (n = 78, P = 0.027).

CONCLUSIONS

Among known HCC patients with preserved liver function, resection was associated with superior patient survival versus transplantation. These results suggest that surgical resection should remain the first line therapy for patients with HCC and compensated liver function who are candidates for resection.

Is surgical resection superior to transplantation in the treatment of hepatocellular carcinoma?

OBJECTIVE

To compare outcomes for patients with hepatocellular carcinoma (HCC) treated with either liver resection or transplantation.

METHODS

A retrospective, single-institution analysis of 413 HCC patients from 1999 to 2009.

RESULTS

A total of 413 patients with HCC underwent surgical resection (n = 106) and transplantation (n = 270) or were listed without receiving transplantation (n = 37). Excluding transplanted patients with incidental tumors (n = 50), 257 patients with suspected HCC were listed with the intent to transplant (ITT). The median diameter of the largest tumor by radiography was 6.0 cm in resected, 3.0 cm in transplanted, and 3.4 cm in the listed-but-not-transplanted patients. Median time to transplant was 48 days. Recurrence rates were 19.8% for resection and 12.1% for all ITT patients. Overall, patient survival for resection versus ITT patients was similar (5-year survival of 53.0% vs 52.0%, not significant). However, for HCC patients with model end-stage liver disease (MELD) scores less than 10 and who radiologically met Milan or UCSF (University of California, San Francisco) criteria, 1-year and 5-year survival rates were significantly improved in resected patients. For patients with MELD score less than 10 and who met Milan criteria, 1-year and 5-year survival were 92.0% and 63.0% for resection (n = 26) versus 83.0% and 41.0% for ITT (n = 73, P = 0.036). For those with MELD score less than 10 and met UCSF criteria, 1-year and 5-year survival was 94.0% and 62.0% for resection (n = 33) versus 81.0% and 40.0% for ITT (n = 78, P = 0.027).

CONCLUSIONS

Among known HCC patients with preserved liver function, resection was associated with superior patient survival versus transplantation. These results suggest that surgical resection should remain the first line therapy for patients with HCC and compensated liver function who are candidates for resection.

Leptin inhibits hepatocellular carcinoma proliferation via p38-MAPK-dependent signalling

OBJECTIVES

Obesity is a significant risk factor for many liver diseases, including hepatocellular carcinoma (HCC). Leptin has been identified as a central mediator of factors that regulate energy intake and expenditure, including appetite, metabolism and fat storage. The role of leptin in the initiation, development and progression of HCC remains poorly understood. The aims of this study were to determine the effect(s) of leptin on HCC cell proliferation and to identify potential signalling mechanism(s) by which leptin exerts these effects.

METHODS

Rat H4IIE HCC cells and H4IIE-derived HCC tumours were analysed for leptin receptor (LR) expression. H4IIE cells were treated with leptin (0-100 ng/ml) in the absence or presence of pharmacological inhibitors of p42/p44 mitogen-activated protein kinase (MAPK) (PD98059), p38-MAPK (SB202190) or Janus kinase-signal transducers and activators of transcription (JAK-STAT) (AG490; 10 µM) signalling. Cell proliferation was determined and signal pathway activity analysed.

RESULTS

Immunohistochemistry identified increased LR expression in HCC in human tissue. Leptin did not significantly affect H4IIE cell numbers in serum-depleted (0.1% [v/v] foetal bovine serum [FBS]) medium. However, leptin significantly inhibited serum-stimulated (1.0% [v/v] FBS) H4IIE proliferation. Immunoblot analysis demonstrated that leptin significantly activated p42/p44-MAPK, p38-MAPK and STAT3 signalling in a time-dependent manner. Pretreatment of H4IIE cells with SB202190 abrogated leptin-dependent inhibition of H4IIE proliferation, an effect not observed in cells pretreated with PD98059 or AG490.

CONCLUSIONS

Leptin inhibits HCC cell growth in vitro via a p38-MAPK-dependent signalling pathway. Identifying similar effects on tumour growth in vivo may provide an attractive therapeutic target for slowing HCC progression.

Use of Encapsulated Stem Cells to Overcome the Bottleneck of Cell Availability for Cell Therapy Approaches

Nowadays cell-based therapy is rarely in clinical practice because of the limited availability of appropriate cells. To apply cells therapeutically, they must not cause any immune response wherefore mainly autologous cells have been used up to now. The amount of vital cells in patients is limited, and under certain circumstances in highly degenerated tissues no vital cells are left. Moreover, the extraction of these cells is connected with additional surgery; also the expansion in vitro is difficult. Other approaches avoid these problems by using allo-or even xenogenic cells. These cells are more stable concerning their therapeutic behavior and can be produced in stock. To prevent an immune response caused by these cells, cell encapsulation (e.g. with alginate) can be performed. Certain studies showed that encapsulated allo- and xenogenic cells achieve promising results in treatment of several diseases. For such cell therapy approaches, stem cells, particularly mesenchymal stem cells, are an interesting cell source. This review deals on the one hand with the use of encapsulated cells, especially stem cells, in cell therapy and on the other hand with bioreactor systems for the expansion and differentiation of mesenchymal stem cells in reproducible and sufficient amounts for potential clinical use.

Silibinin inhibits ethanol metabolism and ethanol-dependent cell proliferation in an in vitro model of hepatocellular carcinoma

Chronic ethanol consumption is a known risk factor for developing hepatocellular carcinoma (HCC). The use of plant-derived antioxidants is gaining increasing clinical prominence as a potential therapy to ameliorate the effects of ethanol on hepatic disease development and progression. This study demonstrates silibinin, a biologically active flavanoid derived from milk thistle, inhibits cytochrome p4502E1 induction, ethanol metabolism and reactive oxygen species generation in HCC cells in vitro. These silibinin-mediated effects also inhibit ethanol-dependent increases in HCC cell proliferation in culture.

Altered aquaporin 9 expression and localization in human hepatocellular carcinoma

BACKGROUND

In addition to the biochemical components secreted in bile, aquaporin (AQP) water channels exist in hepatocyte membranes to form conduits for water movement between the sinusoid and the bile canaliculus. The aim of the current study was to analyse AQP 9 expression and localization in human hepatocellular carcinoma (HCC) and non-tumourigenic liver (NTL) tissue from patients undergoing hepatic resection.

METHODS

Archived tissue from 17 patients was sectioned and analysis performed using an antibody raised against AQP 9. Slides were blind-scored to determine AQP 9 distribution within HCC and NTL tissue.

RESULTS

Aquaporin 9 was predominantly expressed in the membranes of hepatocytes and demonstrated zonal distribution relative to hepatic sinusoid structure in normal liver. In HCC arising in the absence of cirrhosis AQP 9 remained membrane-localized with zonal distribution in the majority of NTL. By contrast, AQP 9 expression was significantly decreased in the HCC mass vs. pair-matched NTL. In HCC in the presence of cirrhosis, NTL was characterized by extensive AQP 9 staining in the membrane in the absence of zonal distribution and AQP 9 staining in NTL was significantly greater than that observed in the tumour mass.

CONCLUSIONS

These data demonstrate that human HCC is characterized by altered AQP 9 expression and AQP 9 localization in the NTL mass is dependent on underlying liver pathology. Given the central role of AQPs in normal liver function and the potential role of AQPs during transformation and progression, these data may prove valuable in future diagnostic and/or therapeutic strategies.

Cell microencapsulation technology: towards clinical application

The pharmacokinetic properties of a drug can be significantly improved by the delivery process. Scientists have understood that developing suitable drug delivery systems that release the therapeutically active molecule at the level and dose it is needed and during the optimal time represents a major advance in the field. Cell microencapsulation is an alternative approach for the sustained delivery of therapeutic agents. This technology is based on the immobilization of different types of cells within a polymeric matrix surrounded by a semipermeable membrane for the long-term release of therapeutics. As a result, encapsulated cells are isolated from the host immune system while allowing exchange of nutrients and waste and release of the therapeutic agents. The versatility of this approach has stimulated its use in the treatment of numerous medical diseases including diabetes, cancer, central nervous system diseases and endocrinological disorders among others. The aim of this review article is to give an overview on the current state of the art of the use of cell encapsulation technology as a controlled drug delivery system. The most important advantages of this type of "living" drug release strategy are highlighted, but also its limitations pointed out, and the major challenges to be addressed in the forthcoming years are described.

Interleukin-6 mediates G(0)/G(1) growth arrest in hepatocellular carcinoma through a STAT 3-dependent pathway

Interleukin-6 (IL-6) is a pleiotropic cytokine that regulates diverse cell functions including proliferation and differentiation. Within the liver IL-6 signaling plays a central role during normal hepatic growth and regeneration yet can inhibit the proliferation of hepatocellular carcinoma (HCC) cells. The aim of the current study was to identify underlying mechanisms whereby IL-6 induces cell-cycle arrest in HCC cells. These studies demonstrate that IL-6 inhibits cell-cycle progression at the G(0)/G(1) interface through inhibition of cyclin-dependent kinase (cdk) 2 and cdk4 activity in the absence of changes in total cyclin (A, D1, D3, and E) or cdk (cdk2, 4, and cdc2 p34) expression. Inhibition of signal transduction pathways associated with IL-6 receptor activation demonstrates that IL-6-dependent inhibition of G(0)-G(1) progression occurs via Janus tyrosine kinase-signal transducers and activators of transcription-3 (Jak-STAT3)-dependent induction of p21(waf1/cip1) and is independent of ERK-MAPK signaling. These data demonstrate that, while IL-6 plays a central role in hepatocyte priming and proliferation in vivo, the pronounced inhibition of proliferation observed in HCC cells occurs due to IL-6-STAT3-dependent regulation of cdk2/cdk4 activity and p21(waf1/cip1) expression.