Technology insight: Utility of TNF-alpha-based isolated limb perfusion to avoid amputation of irresectable tumors of the extremities

Combining high throughput array synthesis and growth algorithm to discover TNF-α binders with new structures and properties

Identifying new chemical structures against protein targets of interest represents one of the major challenges in drug discovery. As the major experimental method, high throughput screenings are performed with existing chemical libraries, thus restricting its capability to explore high molecular diversity. Herein, we report the use of high throughput array synthesis technology, in combination with growth algorithm, to discover binders for proinflammatory cytokine TNF-α. After 6 iterations of Library design - Array synthesis - Screening (i-LAS), one identified compound T17 has shown a kd value of 14.8 μM, and can rescue L929 cells from TNF-α mediated cytotoxicity. Further engineering T17 in various forms of oligomers have led to low nM binders. More interestingly, through tuning the multi-valent interaction with TNF-α, the high affinity oligomers can be switched from inhibitors to activators, leading to the hypothesis of an oligomerization-induced receptor activation mechanism. The i-LAS technology has allowed us to discover new binder structures, which can be further engineered into molecules with novel properties.

Tumor Necrosis Factor: What Is in a Name?

Tumor Necrosis Factor was one of the first cytokines described in the literature as a soluble mediator of cytotoxicity to tumors. Over the years, more extensive research that tried to employ Tumor Necrosis Factor in cancer treatments showed nevertheless that it mainly functioned as a proinflammatory cytokine. However, this did not stop the search for the holy grail of cancer research: A cytokine that could act as a one-stop treatment for solid tumors and lymphomas. This review will summarize the long experimental history of Tumor Necrosis Factor that caused the initial observations of a tumor necrotizing cytokine that could serve as a potential cancer treatment and discuss the current state of research into this side of the activities of Tumor Necrosis Factor.

Identification and Characterization of Tunneling Nanotubes Involved in Human Mast Cell FcεRI-Mediated Apoptosis of Cancer Cells

Simple Summary

Mast cells (MCs) are ubiquitously found in most tissues and in and around tumors. Their role in cancer pathogenesis remains an open area of investigation, and their interactions with tumor cells has not been explored. Here, a novel mechanism of communication between human MCs and tumor cells involving tunneling nanotubes (TnT) and other membrane structures is described. The formation of these communication structures is dependent on MC receptors interacting with tumor antigens through tumor-specific immunoglobulins and results in tumor-killing mediators from MC entering the tumor cells. This mechanism underlying the MC killing of tumor cells has important implications in understanding cancer pathogenesis.

Abstract

Mast cells (MCs) are found in practically all tissues where they participate in innate and adaptive immune responses. They are also found in and around tumors, yet their interactions with cancer cells and the resulting impact on cancer cell growth and metastasis are not well understood. In this study, we examined a novel mechanism of IgE-FcεRI-mediated, intercellular communication between human adipose-derived mast cells (ADMC) and cancer cells. The formation of heterotypic tunneling nanotubes (TnT) and membrane structures between MCs and tumor cells in vitro was examined using microscopy and a diverse array of molecule-specific indicator dyes. We show that several MC-specific structures are dependent on the specific interactions between human tumor IgE-sensitized MCs and antigens on the tumor cell surface. The formation of TnT, membrane blebs and other MC-specific structures paralleled FcεRI-degranulation occurring within 30 min and persisting for up to 24 h. The TnT-specific adhesion of FcεRI-activated MCs to tumor cells was characterized by the transport of the MC granule content into the tumor cells, including tryptase and TNF-α. This interaction led to apoptosis of the tumor cells, which differs from previous studies examining tissue cells within the cancer microenvironment. The formation of heterotypic TnT results in stimulation of an invasive tumor cell phenotype and increased tumor cell invasion and chemoresistance of the cancer cells. These studies describe a heretofore-unrecognized mechanism underlying IgE-mediated interactions and FcεRI-activated MC-mediated killing of tumor cells through the formation of TnT.

Human Tumor Targeted Cytotoxic Mast Cells for Cancer Immunotherapy

The diversity of autologous cells being used and investigated for cancer therapy continues to increase. Mast cells (MCs) are tissue cells that contain a unique set of anti-cancer mediators and are found in and around tumors. We sought to exploit the anti-tumor mediators in MC granules to selectively target them to tumor cells using tumor specific immunoglobin E (IgE) and controllably trigger release of anti-tumor mediators upon tumor cell engagement. We used a human HER2/neu-specific IgE to arm human MCs through the high affinity IgE receptor (FcεRI). The ability of MCs to bind to and induce apoptosis of HER2/neu-positive cancer cells in vitro and in vivo was assessed. The interactions between MCs and cancer cells were investigated in real time using confocal microscopy. The mechanism of action using cytotoxic MCs was examined using gene array profiling. Genetically manipulating autologous MC to assess the effects of MC-specific mediators have on apoptosis of tumor cells was developed using siRNA. We found that HER2/neu tumor-specific IgE-sensitized MCs bound, penetrated, and killed HER2/neu-positive tumor masses in vitro. Tunneling nanotubes formed between MCs and tumor cells are described that parallel tumor cell apoptosis. In solid tumor, human breast cancer (BC) xenograft mouse models, infusion of HER2/neu IgE-sensitized human MCs co-localized to BC cells, decreased tumor burden, and prolonged overall survival without indications of toxicity. Gene microarray of tumor cells suggests a dependence on TNF and TGFβ signaling pathways leading to apoptosis. Knocking down MC-released tryptase did not affect apoptosis of cancer cells. These studies suggest MCs can be polarized from Type I hypersensitivity-mediating cells to cytotoxic cells that selectively target tumor cells and specifically triggered to release anti-tumor mediators. A strategy to investigate which MC mediators are responsible for the observed tumor killing is described so that rational decisions can be made in the future when selecting which mediators to target for deletion or those that could further polarize them to cytotoxic MC by adding other known anti-tumor agents. Using autologous human MC may provide further options for cancer therapeutics that offers a unique anti-cancer mechanism of action using tumor targeted IgE’s.

Autophagy-based unconventional secretion of HMGB1 in glioblastoma promotes chemosensitivity to temozolomide through macrophage M1-like polarization

Background

Glioblastoma (GB) is the most common and highly malignant brain tumor characterized by aggressive growth and resistance to alkylating chemotherapy. Autophagy induction is one of the hallmark effects of anti-GB therapies with temozolomide (TMZ). However, the non-classical form of autophagy, autophagy-based unconventional secretion, also called secretory autophagy and its role in regulating the sensitivity of GB to TMZ remains unclear. There is an urgent need to illuminate the mechanism and to develop novel therapeutic targets for GB.

Methods

Cancer genome databases and paired-GB patient samples with or without TMZ treatment were used to assess the relationship between HMGB1 mRNA levels and overall patient survival. The relationship between HMGB1 protein level and TMZ sensitivity was measured by immunohistochemistry, ELISA, Western blot and qRT-PCR. GB cells were engineered to express a chimeric autophagic flux reporter protein consisting of mCherry, GFP and LC3B. The role of secretory autophagy in tumor microenvironment (TME) was analyzed by intracranial implantation of GL261 cells. Coimmunoprecipitation (Co-IP) and Western blotting were performed to test the RAGE-NFκB-NLRP3 inflammasome pathway.

Results

The exocytosis of HMGB1 induced by TMZ in GB is dependent on the secretory autophagy. HMGB1 contributed to M1-like polarization of tumor associated macrophages (TAMs) and enhanced the sensitivity of GB cells to TMZ. Mechanistically, RAGE acted as a receptor for HMGB1 in TAMs and through RAGE-NFκB-NLRP3 inflammasome pathway, HMGB1 enhanced M1-like polarization of TAMs. Clinically, the elevated level of HMGB1 in sera may serve as a beneficial therapeutic-predictor for GB patients under TMZ treatment.

Conclusions

We demonstrated that enhanced secretory autophagy in GB facilitates M1-like polarization of TAMs to enhance TMZ sensitivity of GB cells. HMGB1 acts as a key regulator in the crosstalk between GB cells and tumor-suppressive M1-like TAMs in GB microenvironment and may be considered as an adjuvant for the chemotherapeutic agent TMZ.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02291-8.

T cell-derived tumor necrosis factor induces cytotoxicity by activating RIPK1-dependent target cell death

TNF ligation of TNF receptor 1 (TNFR1) promotes either inflammation and cell survival by (a) inhibiting RIPK1's death-signaling function and activating NF-κB or (b) causing RIPK1 to associate with the death-inducing signaling complex to initiate apoptosis or necroptosis. The cellular source of TNF that results in RIPK1-dependent cell death remains unclear. To address this, we employed in vitro systems and murine models of T cell-dependent transplant or tumor rejection in which target cell susceptibility to RIPK1-dependent cell death could be genetically altered. We show that TNF released by T cells is necessary and sufficient to activate RIPK1-dependent cell death in target cells and thereby mediate target cell cytolysis independently of T cell frequency. Activation of the RIPK1-dependent cell death program in target cells by T cell-derived TNF accelerates murine cardiac allograft rejection and synergizes with anti-PD1 administration to destroy checkpoint blockade-resistant murine melanoma. Together, the findings uncover a distinct immunological role for TNF released by cytotoxic effector T cells following cognate interactions with their antigenic targets. Manipulating T cell TNF and/or target cell susceptibility to RIPK1-dependent cell death can be exploited to either mitigate or augment T cell-dependent destruction of allografts and malignancies to improve outcomes.

Biomedical Applications of a Novel Class of High-Affinity Peptides

Most therapeutic peptides available on the market today are naturally occurring hormones or protein fragments that were serendipitously discovered to possess therapeutic effects. However, the limited repertoire of available natural resources presents difficulties for the development of new peptide drug candidates. Traditional peptides possess several shortcomings that must be addressed for biomedical applications, including relatively low affinity or specificity toward biological targets compared to antibody- and protein scaffold-based affinity molecules, poor in vivo stability owing to rapid enzymatic degradation, and rapid clearance from circulation owing to their small size. Going forward, it will be increasingly important for scientists to develop novel classes of high-affinity and -specificity peptides against desired targets that mitigate these limitations while remaining compatible with pharmaceutical manufacturing processes. Recently, several highly constrained, artificial cyclic peptides have emerged as platforms capable of generating high-affinity peptide binders against various disease-associated protein targets by combining with phage or mRNA display method, some of which have entered clinical trials. In contrast, although linear peptides are relatively easy to synthesize cost-effectively and modify site-specifically at either N- or C-termini compared to cyclic peptides, there have been few linear peptide-based platforms that can provide high-affinity and -specificity peptide binders.In this Account, we describe the creation and development of a novel class of high-affinity peptides, termed "aptide"-from the Latin word "aptus" meaning "to fit" and "peptide"-and summarize their biomedical applications. In the first part, we consider the design and creation of aptides, with a focus on their unique structural features and binding mode, and address screening and identification of target protein-specific aptides. We also discuss advantages of the aptide platform over ordinary linear peptides lacking preorganized structures in terms of the affinity and specificity of identified peptide binders against target molecules. In the second part, we describe the potential biomedical applications of various target-specific aptides, ranging from imaging and therapy to theranostics, according to the types of aptides and diseases. We show that certain aptides can not only bind to a target protein but also inhibit its biological function, thereby showing potential as therapeutics per se. Further, aptides specific for cancer-associated protein antigens can be used as escort molecules or targeting ligands for delivery of chemotherapeutics, cytokine proteins, and nanomedicines, such as liposomes and magnetic particles, to tumors, thereby substantially improving therapeutic effects. Finally, we present a strategy capable of overcoming the critical issue of short blood circulation time associated with most peptides by constructing a hybrid system between an aptide and a hapten cotinine-specific antibody.

Trial Watch: Immunostimulatory cytokines

During the last two decades, a number of approaches for the activation of the immune system against cancer has been developed. These include highly specific interventions, such as monoclonal antibodies, vaccines and cell-based therapies, as well as relatively unselective strategies, such as the systemic administration of adjuvants and immunomodulatory cytokines. Cytokines constitute a huge group of proteins that, taken together, regulate not only virtually all the aspects of innate and cognate immunity, but also several other cellular and organismal functions. Cytokines operate via specific transmembrane receptors that are expressed on the plasma membrane of target cells and, depending on multiple variables, can engage autocrine, paracrine or endocrine signaling pathways. The most appropriate term for defining the cytokine network is “pleiotropic”: cytokines are produced by - and operate on - multiple, often overlapping, cell types, triggering context-depend biological outcomes as diverse as cell proliferation, chemotaxis, differentiation, inflammation, elimination of pathogens and cell death. Moreover, cytokines often induce the release of additional cytokines, thereby engaging self-amplificatory or self-inhibitory signaling cascades. In this Trial Watch, we will summarize the biological properties of cytokines and discuss the progress of ongoing clinical studies evaluating their safety and efficacy as immunomodulatory agents against cancer.

Immunocytokines are a promising immunotherapeutic approach against glioblastoma

Glioblastoma is a poorly immunogenic cancer, and the successes with recent immunotherapies in extracranial malignancies have, so far, not been translated to this devastating disease. Therefore, there is an urgent need for new strategies to convert the immunologically cold glioma microenvironment into a hot one to enable effective antitumor immunity. Using the L19 antibody, which is specific to a tumor-associated epitope of extracellular fibronectin, we developed antibody-cytokine fusions—immunocytokines—with interleukin-2 (IL2), IL12, or tumor necrosis factor (TNF). We showed that L19 accumulated in the tumor microenvironment of two orthotopic immunocompetent mouse glioma models. Furthermore, intravenous administration of L19-mIL12 or L19-mTNF cured a proportion of tumor-bearing mice, whereas L19-IL2 did not. This therapeutic activity was abolished in RAG−/− mice or upon depletion of CD4 or CD8 T cells, suggesting adaptive immunity. Mechanistically, both immunocytokines promoted tumor-infiltrating lymphocytes and increased the amounts of proinflammatory cytokines within the tumor microenvironment. In addition, L19-mTNF induced tumor necrosis. Systemic administration of the fully human L19-TNF fusion protein to patients with glioblastoma (NCT03779230) was safe, decreased regional blood perfusion within the tumor, and was associated with increasing tumor necrosis and an increase in tumor-infiltrating CD4 and CD8 T cells. The extensive preclinical characterization and subsequent clinical translation provide a robust basis for future studies with immunocytokines to treat malignant brain tumors.

Tumor Vasculature Targeted TNFα Therapy: Reversion of Microenvironment Anergy and Enhancement of the Anti-tumor Efficiency

Tumor cells and tumor-associated stromal cells such as immune, endothelial and mesenchimal cells create a Tumor Microenvironment (TME) which allows tumor cell promotion, growth and dissemination while dampening the anti-tumor immune response. Efficient anti-tumor interventions have to keep into consideration the complexity of the TME and take advantage of immunotherapy and chemotherapy combined approaches. Thus, the aim of tumor therapy is to directly hit tumor cells and reverse endothelial and immune cell anergy. Selective targeting of tumor vasculature using TNFα-associated peptides or antibody fragments in association with chemotherapeutic agents, has been shown to exert a potent stimulatory effect on endothelial cells as well as on innate and adaptive immune responses. These drug combinations reducing the dose of single agents employed have led to minimize the associated side effects. In this review, we will analyze different TNFα-mediated tumor vesseltargeted therapies in both humans and tumor mouse models, with emphasis on the role played by the cross-talk between natural killer and dendritic cells and on the ability of TNFα to trigger tumor vessel activation and normalization. The improvement of the TNFα-based therapy with anti-angiogenic immunomodulatory drugs that may convert the TME from immunosuppressive to immunostimulant, will be discussed as well.

Oncological outcome after hyperthermic isolated limb perfusion for primarily unresectable versus locally recurrent soft tissue sarcoma of extremities

INTRODUCTION

The management of locally advanced extremity soft tissue sarcomas, particularly in terms of a limb salvage strategy, represents a challenge, especially in recurrent tumors. In the context of a patient-tailored multimodal therapy, hyperthermic isolated limb perfusion (ILP) is a promising limb-saving treatment option. We report the outcome of patients with primarily irresectable and locally recurrent soft tissue sarcoma (STS) treated by ILP.

PATIENTS AND METHODS

Data about patient demographics, clinical und histopathological characteristics, tumor response, morbidity and oncological outcome of all patients with STS, who underwent an ILP at our institution in a 10-year period, were retrospectively detected and analyzed.

RESULTS

The cohort comprised 30 patients. Two patients were treated with ILP for palliative tumor control, 13 patients because of a local recurrent soft tissue sarcoma (rSTS) and 15 patients because of primarily unresectable soft tissue sarcoma (puSTS). 25 of the 28 patients with curative intention received surgery after ILP (11 pts with rSTS and 14 pts with puSTS). Histopathologically we observed complete response in 6 patients (24%) and partial responses in 19 patients (76%) with a significant better remission in patients with puSTS (p = 0,043). Limb salvage rate was 75%. Mean follow-up was 69 months [range 13-142 months]. Seven (7/11; 64%) patients with rSTS and one (1/14; 7%) patient with puSTS developed local recurrence after ILP and surgery, whereas eight (8/13; 62%) rSTS patients and seven (7/15; 47%) puSTS patients developed distant metastasis. During follow-up, eight patients (28.5%) died of disease (5/13; 38%) rSTS and 3/15 (20%) puSTS. ILP in the group of previously irradiated sarcoma patients (n = 13) resulted in a limb salvage rate of 69% and was not associated in an increased risk for adverse events.

DISCUSSION

ILP for advanced extremity STS is a treatment option for both puSTS and rSTS resulting in good local control and should be considered in multimodal management. ILP is also a good option for patients after radiation history.

Soft-tissue sarcoma in adults: An update on the current state of histiotype-specific management in an era of personalized medicine

Soft-tissue sarcomas (STS) are rare tumors that account for 1% of all adult malignancies, with over 100 different histologic subtypes occurring predominately in the trunk, extremity, and retroperitoneum. This low incidence is further complicated by their variable presentation, behavior, and long-term outcomes, which emphasize the importance of centralized care in specialized centers with a multidisciplinary team approach. In the last decade, there has been an effort to improve the quality of care for patients with STS based on anatomic site and histology, and multiple ongoing clinical trials are focusing on tailoring therapy to histologic subtype. This report summarizes the latest evidence guiding the histiotype-specific management of extremity/truncal and retroperitoneal STS with regard to surgery, radiation, and chemotherapy.

Ripoptocide - A Spark for Inflammation

The clinical success of biologics that inhibit TNF (Tumor Necrosis Factor) in inflammatory bowel diseases (IBD), psoriasis and rheumatoid arthritis (RA) has clearly established a pathogenic role for this cytokine in these inflammatory disorders. TNF binding to its receptors activates NFκB and MAPK signaling, inducing the expression of downstream pro-inflammatory genes. This is thought to be the primary mechanism by which TNF elicits inflammation. TNF is also a well-known trigger of caspase-dependent apoptosis or caspase-independent necroptosis. Whether cell death has any role in TNF-mediated inflammation has been less clear. Emerging data from animal models now suggest that cellular demise caused by TNF may indeed provoke inflammation. The default response of most cells to TNF stimulation is survival, rather than death, due to the presence of two sequential cell death checkpoints. The early checkpoint is transcription-independent involving the non-degradative ubiquitination of RIPK1 to prevent RIPK1 from becoming a death-signaling molecule. The later checkpoint requires the induction of pro-survival genes by NFκB-mediated transcription. When the early checkpoint is disrupted, RIPK1 initiates cell death and we suggest the term ripoptocide to describe this manner of death (encompassing both apoptosis and necroptosis). The sensitivity of a cell to ripoptocide is determined by the balance between regulatory molecules that enforce and those that disassemble the early checkpoint. As there is evidence suggesting that ripoptocide is inflammatory, individuals may develop inflammation due to ripoptocide brought about by genetic, epigenetic or post-translational alteration of these checkpoint regulators. For these individuals, drugs that reinforce the early checkpoint and inhibit ripoptocide could be useful in ameliorating inflammation.

Trial Watch: Immunostimulation with recombinant cytokines for cancer therapy

Cytokines regulate virtually aspects of innate and adaptive immunity, including the initiation, execution and extinction of tumor-targeting immune responses. Over the past three decades, the possibility of using recombinant cytokines as a means to elicit or boost clinically relevant anticancer immune responses has attracted considerable attention. However, only three cytokines have been approved so far by the US Food and Drug Administration and the European Medicines Agency for use in cancer patients, namely, recombinant interleukin (IL)-2 and two variants of recombinant interferon alpha 2 (IFN-α2a and IFN-α2b). Moreover, the use of these cytokines in the clinics is steadily decreasing, mostly as a consequence of: (1) the elevated pleiotropism of IL-2, IFN-α2a and IFN-α2b, resulting in multiple unwarranted effects; and (2) the development of highly effective immunostimulatory therapeutics, such as immune checkpoint blockers. Despite this and other obstacles, research in the field continues as alternative cytokines with restricted effects on specific cell populations are being evaluated. Here, we summarize research preclinical and clinical developments on the use of recombinant cytokines for immunostimulation in cancer patients.

Monitoring system for isolated limb perfusion based on a portable gamma camera

Background: The treatment of malignant melanoma or sarcomas on a limb using extremity perfusion with tumour necrosis factor (TNF-α) and melphalan can result in a high degree of systemic toxicity if there is any leakage from the isolated blood territory of the limb into the systemic vascular territory. Leakage is currently controlled by using radiotracers and heavy external probes in a procedure that requires continuous manual calculations. The aim of this work was to develop a light, easily transportable system to monitor limb perfusion leakage by controlling systemic blood pool radioactivity with a portable gamma camera adapted for intraoperative use as an external probe, and to initiate its application in the treatment of MM patients. Methods: A special collimator was built for maximal sensitivity. Software for acquisition and data processing in real time was developed. After testing the adequacy of the system, it was used to monitor limb perfusion leakage in 16 patients with malignant melanoma to be treated with perfusion of TNF-α and melphalan. Results: The field of view of the detector system was 13.8 cm, which is appropriate for the monitoring, since the area to be controlled was the precordial zone. The sensitivity of the system was 257 cps/MBq. When the percentage of leakage reaches 10% the associated absolute error is ± 1%. After a mean follow-up period of 12 months, no patients have shown any significant or lasting side-effects. Partial or complete remission of lesions was seen in 9 out of 16 patients (56%) after HILP with TNF-α and melphalan. Conclusion: The detector system together with specially developed software provides a suitable automatic continuous monitoring system of any leakage that may occur during limb perfusion. This technique has been successfully implemented in patients for whom perfusion with TNF-α and melphalan has been indicated.

Targeted Cancer Therapy Using Fusion Protein of TNFα and Tumor-Associated Fibronectin-Specific Aptide

Tumor necrosis factor-α has shown potent antitumor effects in preclinical and clinical studies. However, severe side effects at less than therapeutic doses have limited its systemic delivery, prompting the need for a new strategy for targeted delivery of the protein to tumors. Here, we report a fusion protein of mouse tumor necrosis factor (TNF)-α (mTNFα) and a cancer-targeting, high-affinity aptide and investigate its therapeutic efficacy in tumor-bearing mice. A fusion protein consisting of mTNFα, a linker, and an aptide specific to extra domain B (EDB) of fibronectin (APT_EDB), designated mTNFα-APT_EDB, was successfully produced by expression in Escherichia coli. mTNFα-APT_EDB retained specificity and affinity for its target, EDB. In mice bearing EDB-overexpressing fibrosarcomas, mTNFα-APT_EDB showed greater efficacy in inhibiting tumor growth than mTNFα alone or mTNFα linked to a nonrelevant aptide, without causing an appreciable loss in body weight. Moreover, in vivo antitumor efficacy was further significantly increased by combination treatment with the chemotherapeutic drug, melphalan, suggesting a synergistic effect attributable to enhanced drug uptake into the tumor as a result of TNFα-mediated enhanced vascular permeability. These results suggest that a fusion protein of mTNFα with a cancer-targeting peptide could be a new anticancer therapeutic option for ensuring potent antitumor efficacy after systemic delivery.

Dendritic Mesoporous Silica Nanoparticles for pH-Stimuli-Responsive Drug Delivery of TNF-Alpha

Tumor necrosis factor-alpha (TNF-α) is a pleiotropic immune stimulatory cytokine and natural endotoxin that can induce necrosis and regression in solid tumors. However, systemic administration of TNF-α is not feasible due to its short half-life and acute toxicity, preventing its widespread use in cancer treatment. Dendritic mesoporous silica nanoparticles (DMSN) are used coated with a pH-responsive block copolymer gate system combining charged hyperbranched polyethylenimine and nonionic hydrophilic polyethylenglycol to encapsulate TNF-α and deliver it into various cancer cell lines and dendritic cells. Half-maximal effective concentration (EC₅₀ ) for loaded TNF-α is reduced by more than two orders of magnitude. Particle stability and premature cargo release are assessed with enzyme-linked immunosorbent assay. TNF-α-loaded particles are stable for up to 5 d in medium. Tumor cells are grown in vitro as 3D fluorescent ubiquitination-based cell cycle indicator spheroids that mimic in vivo tumor architecture and microenvironment, allowing real-time cell cycle imaging. DMSN penetrate these spheroids, release TNF-α from its pores, preferentially affect cells in S/G2/M phase, and induce cell death in a time- and dose-dependent manner. In conclusion, DMSN encapsulation is demonstrated, which is a promising approach to enhance delivery and efficacy of antitumor drugs, while minimizing adverse side effects.

Oxaliplatin and Infliximab Combination Synergizes in Inducing Colon Cancer Regression

BACKGROUND Colon cancer is one of the most common malignant cancers and causes millions of deaths each year. There are still no effective treatments for colon cancer patients who are at advanced stage. Tumor necrosis factor-alpha (TNF-α) might be a good therapy target due to its widely-accepted roles in regulating multiple important biological processes, especially in promoting inflammation. MATERIAL AND METHODS We evaluated the expression of TNF-α in 108 human colon cancer tissue samples and 2 colon cancer cell lines (CT26 and HCT116), and analyzed its prognostic values. Further, we explored the roles and mechanism of anti-TNF-α treatment in combination with chemotherapy in vitro and in vivo. RESULTS We found that TNF-α was highly expressed in colon cancer cell lines. The survival analysis and Cox regression analysis indicated that high TNF-α was an independent adverse prognosticator of colon cancer. In addition, anti-TNF-α treatment enhanced the effects of chemotherapy in the xenograft mouse model through inducing ADCC and CDC effects. CONCLUSIONS We conclude that TNF-α is an independent adverse prognosticator of colon cancer, and anti-TNF-α might benefit colon cancer patients.

Isolated limb perfusion for the management limb threatening soft tissue sarcomas: The role of histological type on clinical outcomes

BACKGROUND

Hyperthermic isolated limb perfusion (HILP) is an effective neoadjuvant treatment to avoid amputation in patients with locally advanced extremity soft tissue sarcomas (STS). We aimed to investigate whether STS histological type plays a role in predicting clinical outcomes.

METHODS

This study reports a retrospective analysis of 125 patients with limb threatening STS (liposarcoma, n = 41; malignant peripheral nerve sheath tumor, n = 20; leiomyosarcoma, n = 20; miscellany, n = 44), who underwent HILP from 1990 through 2015 at our institution. The following endpoints were evaluated: tumor response (assessed by radiological imaging and histology), limb sparing rate, local progression-free survival (LPFS) and overall survival (OS).

RESULTS

On average, overall (complete + partial) tumor response was significantly greater in patients affected with liposarcoma as compared to those with other histotypes (radiological response rate: 38/41, 92.7% vs 66/84, 78.6%, P-value: 0.048; mean histological necrosis: 83.6% vs 52.9%, P < 0.0001). Limb sparing rate was also higher among patients with liposarcoma as compared to other histotypes (39/41, 95.1% vs 62/84, 73.8%, P-value: 0.005). As regards survival, LPFS was similar across tumor types, whereas OS resulted significantly worse in patients with limb leiomyosarcoma (log-rank P-value: 0.009).

CONCLUSIONS

HILP is a very effective treatment modality for limb threatening STS. In our series, liposarcoma appears to be the histological type most sensitive to HILP in terms of tumor response and thus limb sparing, which might help clinicians in the patient selection process.

Looking for answers: the current status of neoadjuvant treatment in localized soft tissue sarcomas

PURPOSE

Sarcomas are a rare and heterogeneous variant of cancer. The standard of care treatment involves surgical resection with radiation in high-risk patients. Despite appropriate treatment approximately 50 % of patients will suffer and die from recurrent disease. The purpose of this article is to review the current evidence concerning the use of neoadjuvant chemotherapy with or without radiation in soft tissue sarcomas.

METHODS

An in-depth literature search was conducted using Ovid Medline and PubMed.

RESULTS

The most active chemotherapeutic agents in sarcoma are anthracyclines and ifosfamide. Adjuvant chemotherapy trials show only minimal benefit. Neoadjuvant chemotherapy offers the potential advantage of reducing the extent of surgery, increasing the limb salvage rate, early exposure of micrometastatic disease to chemotherapy, and assessment of tumor response to chemotherapy. Some retrospective and phase II trials suggest a benefit to neoadjuvant chemotherapy. Unfortunately, no clearly positive phase III prospectively randomized trials exist for neoadjuvant therapy in soft tissue sarcomas.

CONCLUSIONS

The current neoadjuvant chemotherapy trials that do exist are heterogeneous resulting in conflicting results. However, neoadjuvant chemotherapy with or without radiation can be considered in patients with high-risk disease in an attempt to improve long-term outcomes.

IAP antagonists sensitize murine osteosarcoma cells to killing by TNFα

Outcomes for patients diagnosed with the bone cancer osteosarcoma have not improved significantly in the last four decades. Only around 60% of patients and about a quarter of those with metastatic disease survive for more than five years. Although DNA-damaging chemotherapy drugs can be effective, they can provoke serious or fatal adverse effects including cardiotoxicity and therapy-related cancers. Better and safer treatments are therefore needed. We investigated the anti-osteosarcoma activity of IAP antagonists (also known as Smac mimetics) using cells from primary and metastatic osteosarcomas that arose spontaneously in mice engineered to lack p53 and Rb expression in osteoblast-derived cells. The IAP antagonists SM-164, GDC-0152 and LCL161, which efficiently target XIAP and cIAPs, sensitized cells from most osteosarcomas to killing by low levels of TNFα but not TRAIL. RIPK1 expression levels and activity correlated with sensitivity. RIPK3 levels varied considerably between tumors and RIPK3 was not required for IAP antagonism to sensitize osteosarcoma cells to TNFα. IAP antagonists, including SM-164, lacked mutagenic activity. These data suggest that drugs targeting XIAP and cIAP1/2 may be effective for osteosarcoma patients whose tumors express abundant RIPK1 and contain high levels of TNFα, and would be unlikely to provoke therapy-induced cancers in osteosarcoma survivors.

Trial Watch-Immunostimulation with cytokines in cancer therapy

During the past decade, great efforts have been dedicated to the development of clinically relevant interventions that would trigger potent (and hence potentially curative) anticancer immune responses. Indeed, developing neoplasms normally establish local and systemic immunosuppressive networks that inhibit tumor-targeting immune effector cells, be them natural or elicited by (immuno)therapy. One possible approach to boost anticancer immunity consists in the (generally systemic) administration of recombinant immunostimulatory cytokines. In a limited number of oncological indications, immunostimulatory cytokines mediate clinical activity as standalone immunotherapeutic interventions. Most often, however, immunostimulatory cytokines are employed as immunological adjuvants, i.e., to unleash the immunogenic potential of other immunotherapeutic agents, like tumor-targeting vaccines and checkpoint blockers. Here, we discuss recent preclinical and clinical advances in the use of some cytokines as immunostimulatory agents in oncological indications.

Targeting antitumor effect of rhTNF-α fusion protein mediated by matrix metalloproteinase-2

The aim of this study was to examine the tumor therapy, targeting effects and side effects of tumor-targeting rhTNF-α fusion protein mediated by matrix metalloproteinase-2 in an animal model in order to provide experimental data for future development of drugs. The median lethal dose (LD50) was obtained from acute toxicity experiments. The A549 lung cancer xenograft model was established, and then randomly divided into the saline, standard substance, and low-, middle- and high-dose fusion protein experiment groups. Each group was administered drugs for 18 days. The length and width of the xenografts were measured every three days, after which the xenograft growth curve was drawn. The mice were sacrificed in each group following treatment and the tumor volume and weight were measured. The targeting, effectiveness and toxicity of the transformed fusion protein, and pathological changes of tumor and organ tissues were examined by hematoxylin and eosin (H&E) staining. Additionally, biochemical markers were used to detect damage of various organs after protein processing. Cell apoptosis and angiogenesis were determined using terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling (TUNEL) testing and immunohistochemistry, respectively, in different dose groups. Tumor growth was markedly retarded in the high-dose experimental and standard hTNF-α groups with antitumor rates of 85.91 and 72.25%, respectively, as compared with the control group. Furthermore, the tumor tissue showed obvious apoptosis (the apoptotic index was 78.78 and 66.65%, respectively) and pathological changes in the high-dose experimental and standard hTNF-α groups. Tumor angiogenesis in each fusion protein group was inhibited (P<0.01) and the biochemical markers of various organs were greatly reduced in the high-dose experimental group (P<0.05). This finding indicated that slight toxic effects of fusion proteins were evident for the heart, liver and kidney. The reforming fusion protein can therefore target tumor tissues and efficiently kill tumor cells, with few side effects.

Trial watch: Immunostimulatory cytokines in cancer therapy

Tumor-targeting immune responses provide a significant contribution to (when they do not entirely account for) the clinical activity of diverse antineoplastic regimens, encompassing not only a large panel of immunotherapeutic strategies but also conventional cytotoxic molecules, targeted anticancer agents and irradiation. In line with this notion, several approaches have been devised to elicit novel or boost existing anticancer immune responses, including the administration of immunomodulatory cytokines. Such a relatively unspecific intervention suffices to mediate clinical effects in (at least a subset of) patients bearing particularly immunogenic tumors, like melanoma and renal cell carcinoma. More often, however, immunostimulatory cytokines are administered to boost the immunogenic potential of other agents, including (but not limited to) immune checkpoint-blocking antibodies, anticancer vaccines, oncolytic viruses and immunogenic chemotherapeutics. Here, we summarize the latest advances in the clinical development of recombinant cytokines as an immunomodulatory intervention for cancer therapy.

Recent advances in osteosarcoma

Although osteosarcoma (OS) is a rare malignancy, it is ranked among the leading causes of cancer-related death in the pediatric age group. The cancer's low prevalence and its large tumor heterogeneity make it difficult to obtain meaningful progress in patient survival. In this review we present an overview of current clinical trials which largely focus on stimulation of the immune system or rely on the inhibition of kinases such as Src and mTOR. The potential efficacy of tumor-targeted TNFalpha is discussed, as well as the importance of preclinical validation of new targets. To improve the success of future clinical trials, clinicians and basic researchers need to intensify their exchange. Finally, a case is made for individualized treatment of OS patients, based on interdisciplinary cooperation in dedicated Sarcoma Centers.

Tumour necrosis factor and cancer

Tumour necrosis factor (TNF) was originally described as a circulating factor that can induce haemorrhagic necrosis of tumours. It is now clear that TNF has many different functions in cancer biology. In addition to causing the death of cancer cells, TNF can activate cancer cell survival and proliferation pathways, trigger inflammatory cell infiltration of tumours and promote angiogenesis and tumour cell migration and invasion. These effects can be explained by the diverse cellular responses TNF can initiate through distinct signal transduction pathways, opening the way for more selective targeting of TNF signalling in cancer therapy.

The pathologic response of resected synovial sarcomas to hyperthermic isolated limb perfusion with melphalan and TNF-α: a comparison with the whole group of resected soft tissue sarcomas

Background

Hyperthermic isolated limb perfusion with tumor necrosis factor-α and melphalan (TM-HILP) has been successfully used to treat limb soft tissue sarcomas (STSs) with high response rates. The data on the effectiveness of HILP-TM for the treatment of STSs are mainly based on various STS types. The aim of this study was to investigate the responses of synovial sarcomas (SS) to TM-HILP.

Methods

A total of 125 TM-HILP-treated tumors (STS^all), including 14 SSs, were included in the study. The tumors were subdivided into proximal and distal limb localizations. Tumor typing (using the WHO classification), resection status (using the UICC classification), and response to therapy were assessed using light microscopy. The SSs were tested for the SYT-SSX translocation using RT-PCR. The following tests were applied: a chi-squared test, a t test, and the Mann-Whitney U test.

Results

The SSs were localized distally more often than were the STS cohort (STS^−SS) (85.7% vs. 32.4%) and were smaller (5.8 cm vs. 10.7 cm). There were no differences in the responder/nonresponder ratios or the mean percentages of pathological regression between the SS and STS^−SS cohorts (74.0% vs. 76.0%). A general localization-dependent difference in the tumor responses to TM-HILP could not be detected in the STS^all cohort (distal, 72.0% vs. proximal, 78.0%); however, a UICC R0 status was more often observed in proximal tumors (distal, 50.0% vs. proximal, 71.4%). There was no association between the SYT-SSX type and SS responses to TM-HILP.

Conclusions

Because of the high response rates, TM-HILP is recommended for the treatment of SSs. The distal limb localization of TM-HILP-treated STSs was generally (STS^all cohort) associated with fewer R0 resections.

Safe TNF-based antitumor therapy following p55TNFR reduction in intestinal epithelium

TNF has remarkable antitumor activities; however, therapeutic applications have not been possible because of the systemic and lethal proinflammatory effects induced by TNF. Both the antitumor and inflammatory effects of TNF are mediated by the TNF receptor p55 (p55TNFR) (encoded by the Tnfrsf1a gene). The antitumor effect stems from an induction of cell death in tumor endothelium, but the cell type that initiates the lethal inflammatory cascade has been unclear. Using conditional Tnfrsf1a knockout or reactivation mice, we found that the expression level of p55TNFR in intestinal epithelial cells (IECs) is a crucial determinant in TNF-induced lethal inflammation. Remarkably, tumor endothelium and IECs exhibited differential sensitivities to TNF when p55TNFR levels were reduced. Tumor-bearing Tnfrsf1a⁺⁺/⁻ or IEC-specific p55TNFR-deficient mice showed resistance to TNF-induced lethality, while the tumor endothelium remained fully responsive to TNF-induced apoptosis and tumors regressed. We demonstrate proof of principle for clinical application of this approach using neutralizing anti-human p55TNFR antibodies in human TNFRSF1A knockin mice. Our results uncover an important cellular basis of TNF toxicity and reveal that IEC-specific or systemic reduction of p55TNFR mitigates TNF toxicity without loss of antitumor efficacy.

Trial Watch: Immunostimulatory cytokines

During the past two decades, the notion that cancer would merely constitute a cell-intrinsic disease has gradually been complemented by a model postulating that the immune system plays a relevant role during all stages of oncogenesis and tumor progression. Along with this conceptual shift, several strategies have been devised to stimulate tumor-specific immune responses, including relatively unselective approaches such as the systemic administration of adjuvants or immunomodulatory cytokines. One year ago, in the July issue of OncoImmunology, we described the main biological features of this large group of proteins and discussed the progress of ongoing clinical studies evaluating their safety and therapeutic potential in cancer patients. Here, we summarize the latest developments in this area of clinical research, focusing on high impact studies that have been published during the last 13 mo and clinical trials launched in the same period to investigate which cytokines can be employed as safe and efficient immunostimulatory interventions against cancer.

Affinity Purification of Tumor Necrosis Factor-α Expressed in Raji Cells by Produced scFv Antibody Coupled CNBr-Activated Sepharose

PURPOSE

Recombinant tumor necrosis factor-alpha (TNF-α) has been utilized as an antineoplastic agent for the treatment of patients with melanoma and sarcoma. It targets tumor cell antigens by impressing tumor-associated vessels. Protein purification with affinity chromatography has been widely used in the downstream processing of pharmaceutical-grade proteins.

METHODS

In this study, we examined the potential of our produced anti-TNF-α scFv fragments for purification of TNF-α produced by Raji cells. The Raji cells were induced by lipopolysaccharides (LPS) to express TNF-α. Western blotting and Fluorescence-activated cell sorting (FACS) flow cytometry analyses were used to evaluate the TNF-α expression. The anti-TNF-α scFv selected from antibody phage display library was coupled to CNBr-activated sepharose 4B beads used for affinity purification of expressed TNF-α and the purity of the protein was assessed by SDS-PAGE.

RESULTS

Western blot and FACS flow cytometry analyses showed the successful expression of TNF-α with Raji cells. SDS-PAGE analysis showed the performance of scFv for purification of TNF-α protein with purity over 95%.

CONCLUSION

These findings confirm not only the potential of the produced scFv antibody fragments but also this highly pure recombinant TNF-α protein can be applied for various in vitro and in vivo applications.

Changes in hepatic blood flow during transcatheter arterial infusion with heated saline in hepatic VX2 tumor

PURPOSE

This study evaluates the influence of transcatheter arterial infusion with heated saline on hepatic arterial and portal venous blood flows to tumor and normal hepatic tissues in a rabbit VX2 tumor model.

METHODS

All animal experiments were approved by the institutional animal care and use committee. Twenty rabbits with VX2 liver tumors were divided into the following two groups: (a) the treated group (n = 10), which received a 60 mL transarterial injection of 60 °C saline via the hepatic artery; (b) the control group (n = 10), which received a 60 mL injection of 37 °C saline via the hepatic artery. Using ultrasonography, the blood flows in both the portal vein and hepatic artery were measured, and the changes in the hemodynamic indices were recorded before and immediately after the injection. The changes in the tumor and normal liver tissues of the two groups were histopathologically examined by hematoxylin and eosin staining after the injection.

RESULTS

After the transcatheter arterial heated infusion, there was a decrease in the hepatic arterial blood flow to the tumor tissue, a significant decrease in the hepatic artery mean velocity (P < 0.05), and a significant increase in the resistance index (P < 0.05). On hematoxylin and eosin staining, there were no obvious signs of tissue destruction in the normal liver tissue or the tumor tissue after heated perfusion, and coagulated blood plasma was observed in the cavities of intratumoral blood vessels in the treated group.

CONCLUSIONS

The changes in tumor blood flow in the rabbit VX2 tumor model were presumably caused by microthrombi in the tumor vessels, and the portal vein likely mediated the heat loss in normal liver tissue during the transarterial heated infusion.

Size-based clinical response evaluation is insufficient to assess clinical response of sarcomas treated with isolated limb perfusion with TNF-α and melphalan

BACKGROUND

The clinical assessment of the response of sarcomas to preoperative treatment is usually defined using size-based evaluation standards. For nonresectable sarcomas, hyperthermic isolated limb perfusion with TNF-α and melphalan (TM-ILP) yields high response rates. Based on our experience, we assume that anatomic radiological response criteria are insufficient to assess the degree of regression after TM-ILP.

METHODS

The clinical response of 35 sarcomas to TM-ILP was assessed by unidimensional, bidimensional, and tridimensional size-based anatomical criteria, and responders were identified according to the established thresholds. The same tumors were investigated for pathological response according to the Salzer-Kuntschik regression scale (>90% devitalization) and reviewed for cystic degeneration, hemorrhage, and predominant necrotic or fibrosclerotic regression phenotype.

RESULTS

None of the clinical response criteria were able to reliably identify the pathologic responders. The extent of size changes showed no association with the pathological degree of regression. The number of clinical responders was low compared with the number of pathological responders (RECIST N = 1, WHO N = 3, volumetry N = 3, pathology N = 19). The occurrence of hemorrhage and/or cystic degeneration was more frequently observed in predominant necrotic sarcomas and was associated with an increase in tumor size after TM-ILP. Furthermore, we identified the fibrosclerotic phenotype of regression to be more significantly strongly associated with posttherapeutic shrinkage than necrosis.

CONCLUSIONS

Size-based clinical response evaluation is insufficient to assess clinical response in TM-ILP-treated sarcomas. The size changes of tumors after therapy reflect the type of regression rather than the extent of destruction.

[Tumor necrosis factor α and melfalan-based hyperthermic isolated limb perfusion in locally advanced extremity soft tissue sarcomas and melanomas]

INTRODUCTION

The aim of the study is to evaluate the limb salvage rate achieved by treating locally advanced extremity sarcoma and melanoma by hyperthermic isolated limb perfusion with melphalan and TNF-α (ILP-MT).

MATERIAL AND METHODS

A retrospective study was conducted on patients suffering from locally advanced soft tissue sarcoma and melanoma of the limb and treated by means of ILP-MT between November 2001 and February 2010. The response rate, toxicity, complications, disease free intervals, overall survival and limb salvage rate were evaluated.

RESULTS

A total of 30 patients (19 females and 11 males) with a median age of 60 years (14-82) were treated by this technique. The overall response rate was 93.4% (complete, 46.7%; partial 46.7%); the mean follow-up was 23 months. The median duration of response was 5 months (0-62), The median overall survival was 13.5 months (range 1 - 62). Limb salvage rate was 86.7%. Eleven patients are currently alive (5 without disease, 2 with residual disease on treatment, 2 with local progression and 2 with systemic progression).

CONCLUSION

With the use of ILP-MT we have avoided the amputation of 26 limbs affected by locally advanced sarcoma or melanoma. ILP-MT is feasible and safe in a multidisciplinary environment.

[Current state of neoadjuvant therapy of soft tissue sarcoma]

The treatment of soft tissue sarcoma is clinically challenging. Referral to an experienced center with an interdisciplinary team is strongly recommended. Neoadjuvant therapy, including irradiation and chemotherapy, has been applied to improve local control rates, eradicate micrometastases and assess chemosensitivity. However, the role of neoadjuvant therapy remains controversial, especially for systemic therapy, as the only available randomized trial failed to prove a benefit for survival. Nevertheless, on the basis of the current body of literature, neoadjuvant therapy can be considered on an individual basis for patients with high-risk tumors. Whenever possible, patients should be included in a clinical trial.

Signal integration, crosstalk mechanisms and networks in the function of inflammatory cytokines

Infection or cell damage triggers the release of pro-inflammatory cytokines such as interleukin(IL)-1α or β and tumor necrosis factor (TNF)α which are key mediators of the host immune response. Following their identification and the elucidation of central signaling pathways, recent results show a highly complex crosstalk between various cytokines and their signaling effectors. The molecular mechanisms controlling signaling thresholds, signal integration and the function of feed-forward and feedback loops are currently revealed by combining methods from biochemistry, genetics and in silico analysis. Increasing evidence is mounted that defects in information processing circuits or their components can be causative for chronic or overshooting inflammation. As progress in biosciences has always benefitted from the use of well-studied model systems, research on inflammatory cytokines may function as a paradigm to reveal general principles of signal integration, crosstalk mechanisms and signaling networks.

Cutaneous melanoma in the elderly: epidemiology, prognosis and treatment

The incidence and mortality of cutaneous melanoma (CM) has increased over the last decades in fair-skinned populations. Incidence and mortality, as well as rates of increase, have been significantly higher in elderly people compared with younger age groups. Lower survival rates from CM among elderly are mainly the result of late diagnosis of tumors with dismal prognostic features. Expansion of current preventive strategies to include older age groups is therefore warranted. Despite differences in clinical presentation and pathological characteristics of CM in the elderly, there is no evidence that primary surgical treatment should differ from that proposed generally for melanoma. However, the rate of positive sentinel node dissection decreases with age, even though overall survival is shorter in older patients, a paradox that remains to be explained. The use of adjuvant treatment with interferon-alpha in elderly patients requires careful discussion of the risks and benefits, especially when serious illness coexists. For metastatic melanoma, complete metastasectomy is the only treatment associated with benefit for overall survival. However, careful selection of surgical oncogeriatric candidates is necessary, probably with the use of tools to provide a comprehensive geriatric assessment, to identify patients more likely to benefit from this treatment. In the absence of any effective systemic treatment for disseminated CM, new therapeutic agents are urgently needed. Practical means to improve accrual of older patients in clinical trials are necessary to provide better evidence for their treatment.

Survival signalling and apoptosis resistance in glioblastomas: opportunities for targeted therapeutics

Glioblastoma multiforme (GBM) is the most common primary brain tumour in adults and one of the most aggressive cancers in man. Despite technological advances in surgical management, combined regimens of radiotherapy with new generation chemotherapy, the median survival for these patients is 14.6 months. This is largely due to a highly deregulated tumour genome with opportunistic deletion of tumour suppressor genes, amplification and/or mutational hyper-activation of receptor tyrosine kinase receptors. The net result of these genetic changes is augmented survival pathways and systematic defects in the apoptosis signalling machinery. The only randomised, controlled phase II trial conducted targeting the epidermal growth factor receptor (EGFR) signalling with the small molecule inhibitor, erlotinib, has showed no therapeutic benefit. Survival signalling and apoptosis resistance in GBMs can be viewed as two sides of the same coin. Targeting increased survival is unlikely to be efficacious without at the same time targeting apoptosis resistance. We have critically reviewed the literature regarding survival and apoptosis signalling in GBM, and highlighted experimental, preclinical and recent clinical trials attempting to target these pathways. Combined therapies simultaneously targeting apoptosis and survival signalling defects might shift the balance from tumour growth stasis to cytotoxic therapeutic responses that might be associated with greater therapeutic benefits.

RNAi-mediated silencing of insulin receptor substrate-4 enhances actinomycin D- and tumor necrosis factor-alpha-induced cell death in hepatocarcinoma cancer cell lines

Insulin receptor substrate-4 (IRS-4) transmits signals from the insulin-like growth factor receptor (IGF-IR) and the insulin receptor (IR) to the PI3K/AKT and the ERK1/2 pathways. IRS-4 expression increases dramatically after partial hepatectomy and plays an important role in HepG2 hepatoblastoma cell line proliferation/differentiation. In human hepatocarcinoma, IRS-4 overexpression has been associated with tumor development. Herein, we describe the mechanism whereby IRS-4 depletion induced by RNA interference (siRNA) sensitizes HepG2 cells to treatment with actinomycin D (Act D) and combined treatment with Act D plus tumor necrosis factor-alpha (TNF-alpha). Similar results have been obtained in HuH 7 and Chang cell lines. Act D therapy drove the cells to a mitochondrial-dependent apoptotic program involving cytochrome c release, caspase 3 activation, PARP fragmentation and DNA laddering. TNF-alpha amplifies the effect of Act D on HepG2 cell apoptosis increasing c-jun N-terminal kinase (JNK) activity, IkappaB-alpha proteolysis and glutathione depletion. IRS-4 depleted cells that were treated with Act D showed an increase in cytochrome c release and procaspase 3 and PARP proteolysis with respect to control cells. The mechanism involved in IRS-4 action is independent of Akt, IkappaB kinase and JNK. IRS-4 down regulation, however, decreased gamma-glutamylcysteine synthetase content and cell glutathione level in the presence of Act D plus TNF-alpha. These results suggest that IRS-4 protects HepG2 cells from oxidative stress induced by drug treatment.

Adjuvant chemotherapy in localized soft tissue sarcomas: still not proven

Soft tissue sarcoma is a rare and heterogeneous group of tumors in terms of histological subtypes, molecular alterations, clinical presentation, and prognosis. Yet, these tumors are most often treated similarly in the localized phase. The standard treatment of these patients requires multidisciplinary management, in particular, careful diagnostic procedures and surgery by an expert physician, preceded or followed by external radiotherapy. The utility of adjuvant chemotherapy has been explored in 14 trials comparing adjuvant chemotherapy with no treatment. Several trials reported a lower risk for local relapse and lower risk for metastatic relapse, but only a few small trials reported longer overall survival. A meta-analysis of all trials failed to demonstrate a significant difference in the relapse-free survival (RFS) or overall survival rates. Two additional trials, reported afterward, presented conflicting results, with a significant benefit in terms of the RFS rate for the trial of the Italian Sarcoma Group, but no difference in the RFS or overall survival rate in the most recent European Organization for Research and Treatment of Cancer trial. We conclude that adjuvant chemotherapy has not been proven to improve the outcome of an unselected population of patients. Several hypotheses are proposed to account for this observation.