Transduction of tumor necrosis factor-related apoptosis-inducing ligand into hematopoietic cells leads to inhibition of syngeneic tumor growth in vivo

Indomethacin-induced oxidative stress enhances death receptor 5 signaling and sensitizes tumor cells to adoptive T-cell therapy

BACKGROUND

Adoptive cell therapy (ACT) using genetically modified T cells has evolved into a promising treatment option for patients with cancer. However, even for the best-studied and clinically validated CD19-targeted chimeric antigen receptor (CAR) T-cell therapy, many patients face the challenge of lack of response or occurrence of relapse. There is increasing need to improve the efficacy of ACT so that durable, curative outcomes can be achieved in a broad patient population.

METHODS

Here, we investigated the impact of indomethacin (indo), a non-steroidal anti-inflammatory drug (NSAID), on the efficacy of ACT in multiple preclinical models. Mice with established B-cell lymphoma received various combinations of preconditioning chemotherapy, infusion of suboptimal dose of tumor-reactive T cells, and indo administration. Donor T cells used in the ACT models included CD4+ T cells expressing a tumor-specific T cell receptor (TCR) and T cells engineered to express CD19CAR. Mice were monitored for tumor growth and survival. The effects of indo on donor T cell phenotype and function were evaluated. The molecular mechanisms by which indo may influence the outcome of ACT were investigated.

RESULTS

ACT coupled with indo administration led to improved tumor growth control and prolonged mouse survival. Indo did not affect the activation status and tumor infiltration of the donor T cells. Moreover, the beneficial effect of indo in ACT did not rely on its inhibitory effect on the immunosuppressive cyclooxygenase 2 (COX2)/prostaglandin E2 (PGE2) axis. Instead, indo-induced oxidative stress boosted the expression of death receptor 5 (DR5) in tumor cells, rendering them susceptible to donor T cells expressing TNF-related apoptosis-inducing ligand (TRAIL). Furthermore, the ACT-potentiating effect of indo was diminished against DR5-deficient tumors, but was amplified by donor T cells engineered to overexpress TRAIL.

CONCLUSION

Our results demonstrate that the pro-oxidative property of indo can be exploited to enhance death receptor signaling in cancer cells, providing rationale for combining indo with genetically modified T cells to intensify tumor cell killing through the TRAIL-DR5 axis. These findings implicate indo administration, and potentially similar use of other NSAIDs, as a readily applicable and cost-effective approach to augment the efficacy of ACT.

Designed ferritin nanocages displaying trimeric TRAIL and tumor-targeting peptides confer superior anti-tumor efficacy

TRAIL is considered a promising target for cancer therapy because it mediates activation of the extrinsic apoptosis pathway in a tumor-specific manner by binding to and trimerizing its functional receptors, DR4 or DR5. Although recombinant human TRAIL has shown high potency and specificity for killing cancer cells in preclinical studies, it has failed in multiple clinical trials for several reasons, including a very short half-life mainly caused by instability of the monomeric form of TRAIL and rapid renal clearance of the off-targeted TRAIL. To overcome such obstacles, we developed a TRAIL-active trimer nanocage (TRAIL-ATNC) that presents the TRAIL ligand in its trimer-like conformation by connecting it to a triple helix sequence that links to the threefold axis of the ferritin nanocage. We also ligated the tumor-targeting peptide, IL4rP, to TRAIL-ATNC to enhance tumor targeting. The developed TRAIL-ATNCIL4rP showed enhanced agonistic activity compared with monomeric TRAIL. The in vivo serum half-life of TRAIL-ATNCIL4rP was ~ 16-times longer than that of native TRAIL. As a consequence of these properties, TRAIL-ATNCIL4rP exhibited efficacy as an anti-tumor agent in vivo against xenograft breast cancer as well as orthotopic pancreatic cancer models, highlighting the promise of this system for development as novel therapeutics against cancer.

Paclitaxel Priming of TRAIL Expressing Mesenchymal Stromal Cells (MSCs-TRAIL) Increases Antitumor Efficacy of Their Secretome

BACKGROUND

Adipose tissue derived MSCs engineered with the tumor necrosis factor-related apoptosis-inducing ligand protein (MSCs-TRAIL) have a significant anticancer activity. MSCs, without any genetic modifications, exposed to high doses of chemotherapeutic agents are able to uptake the drug and release it in amount affecting tumor proliferation. The purpose of this study was to verify the ability of MSCs-TRAIL to uptake and release paclitaxel (PTX) by providing an increased antitumor efficacy.

METHODS

MSCs and MSCs-TRAIL were tested for their sensitivity to Paclitaxel (PTX) by MTT assay and the cells were loaded with PTX according to a standardized procedure. The secretome was analysed by HPLC for the presence of PTX, microarray assay for soluble TRAIL (s-TRAIL) and tested for in vitro anticancer activity.

RESULTS

MSCs-TRAIL were resistant to PTX and able to incorporate and then release the drug. The secretion of s-TRAIL by PTX loaded MSCs-TRAIL was not inhibited and the PTX delivery together with s-TRAIL secretion resulted into an increased antitumor efficacy of cell secretoma as tested in vitro on human pancreatic carcinoma (CFPAC-1) and glioblastoma (U87-MG).

CONCLUSIONS

Our result is the first demonstration of the possible merging of two new MSCs therapy approaches based on genetic manipulation and drug delivery. If confirmed in vivo, this could potentiate the efficacy of MSCs-TRAIL and strongly contribute to reduce the toxicity due to the systemic treatment of PTX.

Engineering Circulating Tumor Cells as Novel Cancer Theranostics

New ways to target and treat metastatic disease are urgently needed. Tumor “self-homing” describes the recruitment of circulating tumor cells (CTCs) back to a previously excised primary tumor location, contributing to tumor recurrence, as well as their migration to established metastatic lesions. Recently, self-homing CTCs have been exploited as delivery vehicles for anti-cancer therapeutics in preclinical primary tumor models. However, the ability of CTCs to self-home and treat metastatic disease is largely unknown.

Methods: Here, we used bioluminescence imaging (BLI) to explore whether systemically administered CTCs home to metastatic lesions and if CTCs armed with both a reporter gene and a cytotoxic prodrug gene therapy can be used to visualize and treat metastatic disease.

Results: BLI performed over time revealed a remarkable ability of CTCs to home to and treat tumors throughout the body. Excitingly, metastatic tumor burden in mice that received therapeutic CTCs was lower compared to mice receiving control CTCs.

Conclusion: This study demonstrates the noteworthy ability of experimental CTCs to home to disseminated breast cancer lesions. Moreover, by incorporating a prodrug gene therapy system into our self-homing CTCs, we show exciting progress towards effective and targeted delivery of gene-based therapeutics to treat both primary and metastatic lesions.

Mesenchymal stem/stromal cell extracellular vesicles: From active principle to next generation drug delivery system

It has been demonstrated that the biological effector of mesenchymal stem/stromal cells (MSCs) is their secretome, which is composed of a heterogeneous pool of bioactive molecules, partially enclosed in extracellular vesicles (EVs). Therefore, the MSC secretome (including EVs) has been recently proposed as possible alternative to MSC therapy. The secretome can be considered as a protein-based biotechnological product, it is probably safer compared with living/cycling cells, it presents virtually lower tumorigenic risk, and it can be handled, stored and sterilized as an Active Pharmaceutical/Principle Ingredient (API). EVs retain some structural and technological analogies with synthetic drug delivery systems (DDS), even if their potential clinical application is also limited by the absence of reproducible/scalable isolation methods and Good Manufacturing Practice (GMP)-compliant procedures. Notably, EVs secreted by MSCs preserve some of their parental cell features such as homing, immunomodulatory and regenerative potential. This review focuses on MSCs and their EVs as APIs, as well as DDS, considering their ability to reach inflamed and damaged tissues and to prolong the release of encapsulated drugs. Special attention is devoted to the illustration of innovative therapeutic approaches in which nanomedicine is successfully combined with stem cell therapy, thus creating a novel class of "next generation drug delivery systems."

TRAIL-NP hybrids for cancer therapy: a review

Cancer is a worldwide health problem. It is now considered as a leading cause of morbidity and mortality in developed countries. In the last few decades, considerable progress has been made in anti-cancer therapies, allowing the cure of patients suffering from this disease, or at least helping to prolong their lives. Several cancers, such as those of the lung and pancreas, are still devastating in the absence of therapeutic options. In the early 90s, TRAIL (Tumor Necrosis Factor-related apoptosis-inducing ligand), a cytokine belonging to the TNF superfamily, attracted major interest in oncology owing to its selective anti-tumor properties. Clinical trials using soluble TRAIL or antibodies targeting the two main agonist receptors (TRAIL-R1 and TRAIL-R2) have, however, failed to demonstrate their efficacy in the clinic. TRAIL is expressed on the surface of natural killer or CD8+ T activated cells and contributes to tumor surveillance. Nanoparticles functionalized with TRAIL mimic membrane-TRAIL and exhibit stronger antitumoral properties than soluble TRAIL or TRAIL receptor agonist antibodies. This review provides an update on the association and the use of nanoparticles associated with TRAIL for cancer therapy.

Proline metabolism supports metastasis formation and could be inhibited to selectively target metastasizing cancer cells

Metastases are the leading cause of mortality in patients with cancer. Metastasis formation requires cancer cells to adapt their cellular phenotype. However, how metabolism supports this adaptation of cancer cells is poorly defined. We use 2D versus 3D cultivation to induce a shift in the cellular phenotype of breast cancer cells. We discover that proline catabolism via proline dehydrogenase (Prodh) supports growth of breast cancer cells in 3D culture. Subsequently, we link proline catabolism to in vivo metastasis formation. In particular, we find that PRODH expression and proline catabolism is increased in metastases compared to primary breast cancers of patients and mice. Moreover, inhibiting Prodh is sufficient to impair formation of lung metastases in the orthotopic 4T1 and EMT6.5 mouse models, without adverse effects on healthy tissue and organ function. In conclusion, we discover that Prodh is a potential drug target for inhibiting metastasis formation.

Drug delivery with living cells

The field of drug delivery has grown tremendously in the past few decades by developing a wide range of advanced drug delivery systems. An interesting category is cell-based drug delivery, which includes encapsulation of drugs inside cells or attached to the surface and subsequent transportation through the body. Another approach involves genetic engineering of cells to secrete therapeutic molecules in a controlled way. The next-generation systems integrate expertise from synthetic biology to generate therapeutic gene networks for highly advanced sensory and output devices. These developments are very exciting for the drug delivery field and could radically change the way we administer biological medicines to chronically ill patients. This review is covering the use of living cells, either as transport system or production-unit, to deliver therapeutic molecules and bioactive proteins inside the body. It describes a wide range of approaches in cell-based drug delivery and highlights exceptional examples.

The interruption of PKC-ι signaling and TRAIL combination therapy against glioblastoma cells

Glioblastoma is a highly aggressive type of brain cancer which currently has limited options for treatment. It is imperative to develop combination therapies that could cause apoptosis in glioblastoma. The aim of this study was to characterize the affect of modified ICA-1, a PKC-iota inhibitor, on the growth pattern of various glioblastoma cell lines. T98G and U87 glioblastoma cells were treated with ICA-1 alone and the absolute cell numbers of each group were determined for cell growth expansion analysis, cell viability analysis, and cell death analysis. Low dose ICA-1 treatment alone significantly inhibited cell growth expansion of high density glioblastoma cells without inducing cell death. However, the high dose ICA-1 treatment regimen provided significant apoptosis for glioblastoma cells. Furthermore, this study was conducted to use a two layer molecular level approach for treating glioblastoma cells with ICA-1 plus an apoptosis agent, tumor-necrosis factor-related apoptosis-inducing ligand (TRAIL), to induce apoptosis in such chemo-refractory cancer cells. Following ICA-1 plus TRAIL treatment, apoptosis was detected in glioblastoma cells via the TUNEL assay and via flow cytometric analysis using Annexin-V FITC/PI. This study offers the first evidence for ICA-1 alone to inhibit glioblastoma cell proliferation as well as the novel combination of ICA-1 with TRAIL to cause robust apoptosis in a caspase-3 mediated mechanism. Furthermore, ICA-1 plus TRAIL simultaneously modulates down-regulation of PKC-iota and c-Jun.

killerFLIP: a novel lytic peptide specifically inducing cancer cell death

One of the objectives in the development of effective cancer therapy is induction of tumor-selective cell death. Toward this end, we have identified a small peptide that, when introduced into cells via a TAT cell-delivery system, shows a remarkably potent cytoxicity in a variety of cancer cell lines and inhibits tumor growth in vivo, whereas sparing normal cells and tissues. This fusion peptide was named killerFLIP as its sequence was derived from the C-terminal domain of c-FLIP, an anti-apoptotic protein. Using structure activity analysis, we determined the minimal bioactive core of killerFLIP, namely killerFLIP-E. Structural analysis of cells using electron microscopy demonstrated that killerFLIP-E triggers cell death accompanied by rapid (within minutes) plasma membrane permeabilization. Studies of the structure of the active core of killerFLIP (-E) indicated that it possesses amphiphilic properties and self-assembles into micellar structures in aqueous solution. The biochemical properties of killerFLIP are comparable to those of cationic lytic peptides, which participate in defense against pathogens and have also demonstrated anticancer properties. We show that the pro-cell death effects of killerFLIP are independent of its sequence similarity with c-FLIP_L as killerFLIP-induced cell death was largely apoptosis and necroptosis independent. A killerFLIP-E variant containing a scrambled c-FLIP_L motif indeed induced similar cell death, suggesting the importance of the c-FLIP_L residues but not of their sequence. Thus, we report the discovery of a promising synthetic peptide with novel anticancer activity in vitro and in vivo.

TRAIL receptor signaling and therapeutic option in bone tumors: the trap of the bone microenvironment

Tumor Necrosis Factor-Related Apoptosis Inducing Ligand (TRAIL/TNFSF10) has been reported to specifically induce malignant cell death being relatively nontoxic to normal cells. Since its identification 15 years ago, the antitumor activity and therapeutic value of TRAIL have been extensively studied. Five receptors quickly emerged, two of them being able to induce programmed cell death in tumor cells. This review takes a comprehensive look at this ligand and its receptors, and its potential role in primary bone tumors (osteosarcoma and Ewing's sarcoma) therapy. The main limit of clinical use of TRAIL being the innate or acquired resistance mechanisms, different possibilities to sensitize resistant cells are discussed in this review, together with the impact of bone microenvironment in the regulation of TRAIL activity.

Regulatory functions of TRAIL in hematopoietic progenitors: human umbilical cord blood and murine bone marrow transplantation

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) signaling pathway has selective toxicity to malignant cells. The TRAIL receptors DR4 and DR5 are expressed at low levels in human umbilical cord blood cells (3-15%) and are upregulated by incubation with the cognate ligand, triggering apoptosis in 70-80% of receptor-positive cells (P<0.001). Apoptosis is not induced in hematopoietic progenitors, as determined from sustained severe combined immunodeficiency reconstituting potential and clonogenic activity. Furthermore, elimination of dead cells after incubation with TRAIL for 72 h results in a threefold enrichment in myeloid progenitors. Exposure to TRAIL in semisolid cultures showed synergistic activity of DR4 and granulocyte/macrophage colony-stimulating factor in recruiting lineage-negative (lin(-)) and CD34(+) progenitors and in promoting the formation of large colonies. In murine bone marrow, approximately 30% of lin(-) cells express TRAIL-R2 (the only murine receptor), and the receptor is upregulated after transplantation in cycling and differentiating donor cells that home to the host marrow. However, this receptor is almost ubiquitously expressed in the most primitive (lin(-)SCA-1(+)c-kit(+)) progenitors, and stimulates the clonogenic activity of lin(-) cells (P<0.001), suggesting a tropic function after transplantation. It is concluded that TRAIL does not trigger apoptosis in hematopoietic progenitors, and upregulation of its cognate receptors under stress conditions mediates tropic signaling that supports recovery from hypoplasia.

Functional implication of TRAIL -716 C/T promoter polymorphism on its in vitro and in vivo expression and the susceptibility to sporadic breast tumor

Recently, TRAIL function has been elucidated beyond its known classical role of mediating cellular homeostasis and immune surveillance against transformed cells. Here, we show how CC genotype of -716 TRAIL promoter SNP rendered risk for sporadic breast cancer as compared to the CT and TT genotypes (P (recessive model) = 0.018, OR = 1.4, 95% CI = 1.1-1.9; P (allele model) = 0.010, OR = 1.3, 95% CI = 1.1-1.7). The in silico prediction of the introduction of core Sp1/Sp3-binding motif suggested the functional significance of the SNP variation. This functional implication was validated by luciferase assay in HeLa (P = 0.026), MCF-7 (P = 0.022), HepG2 (P = 0.024), and HT1080 (P = 0.030) cells and also by real-time expression studies on tumor tissues (P = 0.01), revealing the transcriptionally repressed status of -716 T when compared to -716 C allele. The SNP-SNP interactions reflected an enhanced protective effect of CT and TT genotypes with the protective genetic backgrounds of TP53-BRCA2 (P = 0.002, OR = 0.2, 95% CI = 0.1-0.6), IFNG (P = 0.0000002, OR = 0.3, 95% CI = 0.2-0.4), and common variant Casp8 (P = 0.0003, OR = 0.5, 95% CI = 0.3-0.7). Interestingly, a comparison with clinical parameters showed overrepresented CT and TT genotypes in progressing (P = 0.041) and ER/PR negative tumors (P = 0.024/0.006). This was explained by increased apoptotic index, calculated as a ratio of selected pro-apoptotic and anti-apoptotic gene expression profiles, in CC genotyped tumors, favoring either intrinsic (P = 0.008,0.018) or extrinsic (P = 0.025,0.217) pathway depending upon the ER/PR status. Our study reveals for the first time that a promoter SNP of TRAIL functionally modulates the gene and consequently its role in breast cancer pathogenesis, cautioning to consider the -716 TRAIL SNP status in patients undergoing TRAIL therapy.

TRAILing death in cancer

The observation that certain types of cancer express death receptors on their cell surface has triggered heightened interest in exploring the potential of receptor ligation as a novel anti-cancer modality, and since the expression is somewhat restricted to cancer cells the therapeutic implications are very promising. One such death receptor ligand belonging to the tumor necrosis receptor (TNF) superfamily, TNF-related apoptosis-inducing ligand (TRAIL), has been in the limelight as a tumor selective molecule that transmits death signal via ligation to its receptors (TRAIL-R1 and TRAIL-R2 or death receptors 4 and 5; DR4 and DR5). Interestingly, TRAIL-induced apoptosis exhibits hallmarks of extrinsic as well as intrinsic death pathways, and, therefore, is subject to regulation both at the cell surface receptor level as well as more downstream at the post-mitochondrial level. Despite the remarkable selectivity of DR expression on cancer cell surface, development of resistance to TRAIL-induced apoptosis remains a major challenge. Therefore, unraveling the cellular and molecular mechanisms of TRAIL resistance as well as identifying strategies to overcome this problem for an effective therapeutic response remains the cornerstone of many research endeavors. This review aims at presenting an overview of the biology, function and translational relevance of TRAIL with a specific view to discussing the various regulatory mechanisms and the current trends in reverting TRAIL resistance of cancer cells with the obvious implication of an improved clinical outcome.

Proteasome inhibition causes regression of leukemia and abrogates BCR-ABL-induced evasion of apoptosis in part through regulation of forkhead tumor suppressors

BCR-ABL plays an essential role in the pathogenesis of chronic myeloid leukemia (CML) and some cases of acute lymphocytic leukemia (ALL). Although ABL kinase inhibitors have shown great promise in the treatment of CML, the persistence of residual disease and the occurrence of resistance have prompted investigations into the molecular effectors of BCR-ABL. Here, we show that BCR-ABL stimulates the proteasome-dependent degradation of members of the forkhead family of tumor suppressors in vitro, in an in vivo animal model, and in samples from patients with BCR-ABL-positive CML or ALL. As several downstream mediators of BCR-ABL are regulated by the proteasome degradation pathway, we also show that inhibition of this pathway, using bortezomib, causes regression of CML-like disease. Bortezomib treatment led to inhibition of BCR-ABL-induced suppression of FoxO proteins and their proapoptotic targets, tumor necrosis factor-related apoptosis-inducing ligand and BIM, thereby providing novel insights into the molecular effects of proteasome inhibitor therapy. We additionally show sensitivity of imatinib-resistant BCR-ABL T315I cells to bortezomib. Our data delineate the involvement of FoxO proteins in BCR-ABL-induced evasion of apoptosis and provide evidence that bortezomib is a candidate therapeutic in the treatment of BCR-ABL-induced leukemia.

Maintaining and engineering neural stem cells for delivery of genetically encoded therapy to brain tumors

Despite advances for the treatment of cancer, the prognosis for patients suffering from malignant brain tumors remains dismal. High-grade neoplasms, such as gliomas, are highly invasive and spawn widely disseminated microsatellites that have limited the efficacy of surgical and adjunctive therapies. The cancer stem cell hypothesis suggests that conventional chemotherapeutic treatments kill differentiated and differentiating cells which often form the bulk of the tumor. One major concern is that the cells which give rise to the tumor, the cancer stem cells, remain untouched and may be responsible for a relapse of the disease. Therefore, an adjunctive therapy to current cancer treatment is critical for the survivability of patients suffering from brain tumors. We have successfully engineered tumor-tropic neural stem cells to deliver antineoplastic gene products directly to the tumor-producing cells. This potential therapeutic strategy may safely eradicate tumor-producing cells in the brain while minimizing damage to normal, healthy cells.

A double hit to kill tumor and endothelial cells by TRAIL and antiangiogenic 3TSR

As tumor development relies on a coordination of angiogenesis and tumor growth, an efficient antitumor strategy should target both the tumor and its associated vessels. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in a tumor-selective manner. Additionally, thrombospondin-1, a naturally occurring inhibitor of angiogenesis, and a recombinant protein containing functional domains of thrombospondin-1, 3TSR, have been shown to be necessary and sufficient to inhibit tumor angiogenesis. Here, we show that a combination of a TRAIL receptor 2 agonist antibody, Lexatumumab, and 3TSR results in a significantly enhanced and durable tumor inhibition. We further observed that 3TSR induces apoptosis in primary endothelial cells by up-regulating the expression of TRAIL receptors 1 and 2 in a CD36 and Jun NH(2)-terminal kinase-dependent manner leading to the activation of both intrinsic and extrinsic apoptotic machineries. The modulation of these pathways is critical for 3TSR-induced apoptosis as disrupting either via specific inhibitors reduced apoptosis. Moreover, 3TSR attenuates the Akt survival pathway. These studies indicate that 3TSR plays a critical role in regulating the proapoptotic signaling pathways that control growth and death in endothelial cells and that a combination of TRAIL and 3TSR acts as a double hit against tumor and tumor-associated vessels.

The TRAIL apoptotic pathway in cancer onset, progression and therapy

Triggering of tumour cell apoptosis is the foundation of many cancer therapies. Death receptors of the tumour necrosis factor (TNF) superfamily have been largely characterized, as have the signals that are generated when these receptors are activated. TNF-related apoptosis-inducing ligand (TRAIL) receptors (TRAILR1 and TRAILR2) are promising targets for cancer therapy. Herein we review what is known about the molecular control of TRAIL-mediated apoptosis, the role of TRAIL in carcinogenesis and the potential therapeutic utility of recombinant TRAIL and agonistic antibodies against TRAILR1 and TRAILR2.

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) induced mitochondrial pathway to apoptosis and caspase activation is potentiated by phospholipid scramblase-3

Tumor Necrosis Factor (TNF)-Related Apoptosis-Inducing Ligand (TRAIL) initiate pathways of cell death in which caspase activation is mediated either directly (without mitochondrial amplification), or indirectly via the release of apoptogenic factors from mitochondria. Phospholipid scramblases (PLS) are enzymes that play a key role in cellular function by inducing bidirectional movement of membrane lipids. Changes in mitochondrial membrane lipids, cardiolipin, are critical for mediating apoptotic response in many cell-types. PLS3 is a phospholipid scramblase that is localized to mitochondria and is thought to be involved in the regulation of apoptotic signals. Here we report that exogenous-expression of PLS3 enhances apoptotic death induced by TRAIL. This is acheived by potentiating the mitochondrial arm of the death pathway. Thereby, PLS3 expression facilitates changes in mitochondrial membrane lipids that promote the release of apoptogenic factors and consequent full activation and processing of the caspase-9 and effector caspase-3. Moreover, we show that knock-down of endogenous PLS3 suppresses TRAIL-induced changes in cardiolipin. Finally, we demonstrate that TRAIL-induced activation of PKC-delta mediates regulation of the PLS3-induced changes in cardiolipin.

Cell-based drug delivery

Drug delivery has been greatly improved over the years by means of chemical and physical agents that increase bioavailability, improve pharmacokinetic and reduce toxicities. At the same time, cell based delivery systems have also been developed. These possesses a number of advantages including prolonged delivery times, targeting of drugs to specialized cell compartments and biocompatibility. Here we'll focus on erythrocyte-based drug delivery. These systems are especially efficient in releasing drugs in circulations for weeks, have a large capacity, can be easily processed and could accommodate traditional and biologic drugs. These carriers have also been used for delivering antigens and/or contrasting agents. Carrier erythrocytes have been evaluated in thousands of drug administration in humans proving safety and efficacy of the treatments. Erythrocyte-based delivery of new and conventional drugs is thus experiencing increasing interests in drug delivery and in managing complex pathologies especially when side effects could become serious issues.

Analysis of TNF-related apoptosis-inducing ligand in vivo through bone marrow transduction and transplantation

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF family of cytokines. TRAIL has gained much attention because of its ability to preferentially kill tumor cells with no apparent toxic side effects. Recently, different TRAIL receptor agonists, including TRAIL itself and various agonistic monoclonal antibodies against the two apoptosis-inducing human TRAIL receptors, have been developed as novel cancer therapeutics and are currently under investigation in clinical trials. However, the mechanisms by which TRAIL mediates its selective antineoplastic activity are still not well understood. In addition to playing a role in cancer immune surveillance and tumor suppression, TRAIL has been associated with immune homeostasis, inflammatory diseases, and autoimmunity. In light of the multifunctional role of TRAIL in mediating various pathologic conditions and the potential benefits of TRAIL-based therapies, the study of the physiologic significance of TRAIL is of great importance. Here, we describe a syngeneic system for the characterization of the in vivo function of TRAIL. By use of this model, in which the full-length murine TRAIL protein is overexpressed in the hematopoietic cells of wild-type mice, the in vivo tumoricidal activity of TRAIL overexpression can be studied on syngeneic murine tumor cell challenge, and the potential toxicity of TRAIL protein to normal tissues can also be analyzed.

TRAIL in cancer therapy: present and future challenges

Since its identification in 1995, TNF-related apoptosis-inducing ligand (TRAIL) has sparked growing interest in oncology due to its reported ability to selectively trigger cancer cell death. In contrast to other members of the TNF superfamily, TRAIL administration in vivo is safe. The relative absence of toxic side effects of this naturally occurring cytokine, in addition to its antitumoural properties, has led to its preclinical evaluation. However, despite intensive investigations, little is known in regards to the mechanisms underlying TRAIL selectivity or efficiency. An appropriate understanding of its physiological relevance, and of the mechanisms controlling cancer cells escape from TRAIL-induced cell death, will be required to optimally use the cytokine in clinics. The present review focuses on recent advances in the understanding of TRAIL signal transduction and discusses the existing and future challenges of TRAIL-based cancer therapy development.

Lack of high affinity fiber receptor activity explains the resistance of ciliated airway epithelia to adenovirus infection

Although recombinant adenoviruses are attractive vectors for gene transfer to airway epithelia, they have proven to be relatively inefficient. To investigate the mechanisms of adenovirus-mediated gene transfer to airway epithelia, we examined the role of adenovirus fiber and penton base, the two proteins involved in attachment to and entry of virus into the cell. We used human airway epithelia grown under conditions that allow differentiation and development of a ciliated apical surface that closely resembles the in vivo condition. We found that addition of fiber protein inhibited virus binding and vector-mediated gene transfer to immature airway epithelia, as well as to primary cultures of rat hepatocytes and HeLa cells. However, fiber protein had no effect on vector binding and gene transfer to ciliated airway epithelia. We obtained similar results with addition of penton base protein: the protein inhibited gene transfer to immature epithelia, whereas there was no effect with ciliated epithelia. Moreover, infection was not attenuated with an adenovirus containing a mutation in penton base that prevents the interaction with cell surface integrins. These data suggest that the receptors required for efficient infection by adenovirus are either not present or not available on the apical surface of ciliated human airway epithelia. The results explain the reason for inefficient gene transfer and suggest approaches for improvement.