Effects of Liposome-Entrapped Muramyl Tripeptide Phosphatidylethanolamine (L-MTP-PE) on the Tumor Growth and Survival of Mice Bearing Syngeneic Tumor in Combination with a Chemotherapeutic or Immunomodulatory Agent.

Antitumor activities of L-MTP-PE (Liposome entrapped myuramyl tripeptide phosphatidylethanolamine) in the combination treatment with chemo- or immune-therapeutic antitumor agents against various syngeneic tumors were tested.Against Meth A fibrosarcoma solid tumor system, L-MTP-PE showed slight but statistically significant elongation of survival days against 5-FU monotherapy in spite of its non-effect on tumor growth, when combined with 5-FU. Against liver metastasis model of M5076 carcinoma, L-MTP-PE showed a tendency of elongation of survival days by its single drug treatment, however, elongation with statistical significance was observed in the combination treatment with 5-FU in comparison with control group.These data suggest that L-MTP-PE seems to elongate the survival days of the solid tumor bearing mice and the liver metastasis model basically due to its saving effect on chemotherapeutic drug-induced immunosuppression. In the combination with an immunotherapeutic agent in mice, TNF production induced by another biological response modifier OK-432 was potentiated when primed with L-MTP-PE. L-MTP-PE also potentiate the antitumor effect of OK-432 possibly through the enhanced production of TNF-α. Combination of L-MTP-PE and OK-432 is considered to be a candidate for a new treatment model for cancer.

Outcomes from a mechanistic biomarker multi-arm and randomised study of liposomal MTP-PE (Mifamurtide) in metastatic and/or recurrent osteosarcoma (EuroSarc-Memos trial).

The phase III clinical study of adjuvant liposomal muramyl tripeptide (MTP-PE) in resected high-grade osteosarcoma (OS) documented positive results that have been translated into regulatory approval, supporting initial promise for innate immune therapies in OS. There remains, however, no new approved treatment such as MTP-PE for either metastatic or recurrent OS. Whilst the addition of different agents, including liposomal MTP-PE, to surgery for metastatic or recurrent high-grade osteosarcoma has tried to improve response rates, a mechanistic hiatus exists in terms of a detailed understanding the therapeutic strategies required in advanced disease. Here we report a Bayesian designed multi-arm, multi-centre, open-label phase II study with randomisation in patients with metastatic and/or recurrent OS, designed to investigate how patients with OS might respond to liposomal MTP-PE, either given alone or in combination with ifosfamide. Despite the trial closing because of poor recruitment within the allocated funding period, with no objective responses in eight patients, we report the design and feasibility outcomes for patients registered into the trial. We demonstrate the feasibility of the Bayesian design, European collaboration, tissue collection with genomic analysis and serum cytokine characterisation. Further mechanistic investigation of liposomal MTP-PE alone and in combination with other agents remains warranted in metastatic OS.

The addition of the immunomodulator mifamurtide to adjuvant chemotherapy for early osteosarcoma: a retrospective analysis.

BACKGROUND: Current treatment recommendations for high grade non-metastatic osteosarcoma include perioperative chemotherapy and surgery. Despite this intensive protocol, approximately 40% of patients will relapse. The addition of the immunomodulator mifamurtide to adjuvant cytotoxic chemotherapy was associated with a significant improvement in 6-year overall survival (OS) in young patients with resectable osteosarcoma, leading to its approval in Europe and other countries. Very limited real-world data are reported on its use. METHODS: We retrospectively evaluated data from osteosarcoma patients who received mifamurtide in the adjuvant setting. Data were obtained from medical records in 2 high-volume bone sarcoma centers. The aim of this study was to collect real-world data on mifamurtide safety and efficacy in Greece. RESULTS: We identified 15 patients with completely resected osteosarcoma who received mifamurtide from September 2015 to January 2020. Median age at diagnosis was 24 years old (16-76). Osteosarcoma arose in the lower extremities (n = 12), in the upper extremities (n = 2) or in the ilium (n = 1). The majority of patients (n = 13) received cisplatin/doxorubicin/methotrexate as perioperative chemotherapy and the remaining patients cisplatin/doxorubicin. After a median follow-up of 46.9 months (range, 32.8-61.1), the median recurrence-free survival was 58.7 months (range, 18.5-98.8) and the median OS 64.1 months (range, 25.6-102.6). Except for fever and chills, the only adverse event probably related to mifamurtide was pericarditis (n = 1). CONCLUSIONS: Mifamurtide was well tolerated in a Greek osteosarcoma population, including patients older than 30 years. The small sample size and the non-comparative design do not allow drawing conclusions on the drug benefit in terms of survival.

Novel chimeric TLR2/NOD2 agonist CL429 exhibited significant radioprotective effects in mice.

Severe ionizing radiation causes the acute lethal damage of haematopoietic system and gastrointestinal tract. Here, we found CL429, the novel chimeric TLR2/NOD2 agonist, exhibited significant radioprotective effects in mice. CL429 increased mice survival, protected mice against the lethal damage of haematopoietic system and gastrointestinal tract. CL429 was more effective than equivalent amounts of monospecific (TLR2 or NOD2) and combination (TLR2 + NOD2) of molecules in preventing radiation-induced death. The radioprotection of CL429 was mainly mediated by activating TLR2 and partially activating NOD2. CL429-induced radioprotection was largely dependent on the activation of TLR2-MyD88-NF-κB signalling pathway. In conclusion, the data suggested that the co-activation of TLR2 and NOD2 could induce significant synergistic radioprotective effects and CL429 might be a potential high-efficiency selective agent.

Type 4 hypersensitivity development in a case due to mifamurtide.

BACKGROUND: This report aims to discuss the mechanism of pleural and pericardial effusion related to mifamurtide which is an immunological agent used as adjuvant chemotherapy in osteosarcoma. CASE: Mifamurtide (2 mg/m < sup > 2 < /sup > ) and European and American Osteosarcoma Studies (EURAMOS) protocol were used together intravenously after complete surgical resection. No side effects occurred except for fever after the first dose. However, pleural, pericardial effusion, and splenic nodule formation began 11 months after discontinuation of mifamurtide treatment. Pleural biopsy revealed a type 4 hypersensitivity reaction. We treated the patient with 1,5 mg per day colchicine. Pericardial effusion attacks and nodules in the spleen disappeared. The patient had a mild pleural effusion attack which has not yet repeated. CONCLUSION: Mifamurtide, which activates macrophages, can also activate immunity with a stand by effect and cause a hypersensitivity reaction.

Muramyl Tripeptide Plus Chemotherapy Reduces Metastasis in Non-Metastatic Osteosarcoma: A Single-Center Experience.

BACKGROUND: The immunomodulator mifamurtide plus a chemotherapy regimen has been shown to significantly improve the outcome in non-metastatic osteosarcoma patients. We report the results of the addition of mifamurtide to chemotherapy in newly diagnosed patients with osteosarcoma. METHODS: A total of 36 children with osteosarcoma without detectable metastasis were treated between November 2010 and April 2018 at the Ankara University Department of Pediatric Oncology. Mifamurtide was added to the chemotherapy regimen in 17 patients while the remaining 19 did not receive mifamurtide. The probabilities of metastasis and overall survival were compared between the groups. RESULTS: The 43-month survival rate was 87.5% and 89.9% in the patients who received and did not receive mifamurtide, respectively (p=0.65). Common side effects of mifamurtide were chills and fever. The addition of mifamurtide in the high-risk group with ≤95% necrosis tended to decrease the probability of distant metastasis (36.4% vs. 58.3%) (p=0.39). The time to metastasis in the group with positive surgical margins (4 months in one patient in the non-mifamurtide group, 7 and 20 months in the mifamurtide group) was also longer in the mifamurtide group. During the 43-month follow up period, median time to metastasis was longer in the mifamurtide group (20 vs. 5 months). In addition, mifamurtide plus chemotherapy decreased the risk of metastasis in the cases with primary site relapse. CONCLUSIONS: The addition of mifamurtide to chemotherapy might improve event-free survival by decreasing the probability of distant metastasis in bad histologic responders, and also by increasing the time to distant metastasis in the surgical margin positive group. Additional clinical studies are necessary to determine the long-term effects of mifamurtide on metastatic disease.
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The Brief Analysis of Peptide-combined Nanoparticle: Nanomedicine's Unique Value.

Therapeutic peptides (TPs) are biological macromolecules which can act as neurotransmitters, hormones, ion channel ligands and growth factors. Undoubtedly, TPs are crucial in modern medicine. But low bio-stability and some special adverse reactions reduce their places to the application. With the development of nanotechnology, nanoparticles (NPs) in pharmaceutical science gained much attention. They can encapsulate the TPs into their membrane or shell. Therefore, they can protect the TPs against degradation and then increase the bioavailability, which was thought to be the biggest advantage of them. Additionally, targeting was also studied to improve the effect of TPs. However, there were some drawbacks of nano TPs like low loading efficiency and difficulty to manufacture. Nowadays, lots of studies focused on improving effect of TPs by preparing nanoparticles. In this review, we presented a brief analysis of peptide-combined nanoparticles. Their advantages and disadvantages were listed in terms of mechanism. And several examples of applications were summarized.

NOD2 agonist murabutide alleviates radiation-induced injury through DNA damage response pathway mediated by ATR.

Injury-induced by ionizing radiation (IR) severely reduces the quality of life of victims. The development of radiation protectors is regarded as one of the most resultful strategies to alleviate damages caused by IR exposure. In the present study, we investigated the radioprotective effects of the agonist of nucleotide-binding-oligomerization-domain-containing proteins 2 called murabutide (MBD) and clarified the potential mechanisms. Our results showed that the pretreatment with MBD effectively protected cultured cells and mice against IR-induced toxicity and the pretreatment with MBD in vitro and in vitro also inhibited apoptosis caused by IR exposure. The downregulation of γ-H2AX and the upregulation of ATR signaling pathways by MBD treatment indicated that the radioprotective effects of MBD were due to the stimulation of DNA damage response (DDR) pathway to repair DNA double-strand breaks caused by IR exposure. As the radioprotective effects of MBD were diminished by the ATR selective inhibitor rather than the ATM inhibitor, ATR pathway was confirmed to be a more crucial checkpoint pathway in mediating the stimulation of DDR pathway by MBD. Taken together, our data provide a novel and effective protector to relieve the injury induced by IR exposure.

Sarcome-13/OS2016 trial protocol: a multicentre, randomised, open-label, phase II trial of mifamurtide combined with postoperative chemotherapy for patients with newly diagnosed high-risk osteosarcoma.

INTRODUCTION: The controversial results on the mifamurtide efficacy associated with chemotherapy, issued from the American INT-0133-study, in localised osteosarcomas, and the underpowered analysis performed separately in metastatic patients, should be clarified to homogenise international use of this promising drug. The European Commission has granted a marketing authorisation to mifamurtide combined with postoperative chemotherapy in localised osteosarcomas but not in metastatic patients, while the Food and Drug Administration (FDA) has denied this authorisation. METHODS AND ANALYSIS: Sarcome-13/OS2016 trial is a multicentre randomised open-label phase II trial evaluating the survival benefit of mifamurtide administered during 36 weeks in combination with postoperative chemotherapy versus chemotherapy alone, in patients >2 and ≤50 years with newly diagnosed high-risk localised or metastatic osteosarcoma. The main objective is to evaluate the impact on event-free survival (EFS) of mifamurtide on intention-to-treat population. The secondary objectives are to evaluate the impact of mifamurtide on overall survival, to evaluate the feasibility and toxicity of the planned treatment, to correlate biology/immunology with the mifamurtide efficacy/toxicity. With a total of 126 enrolled patients and 51 events, the power is 80% if mifamurtide is associated with an 18% improvement of the 3-year EFS (52%vs70%, equivalent to an HR=0.55), with a one-sided logrank test alpha=10%. As relevant historical data are available (aggregate treatment effect from the INT-0133 trial and individual data from the control group of the Sarcome-09/OS2006 trial), a Bayesian analysis is also planned. ETHICS AND DISSEMINATION: This study was approved by the 'Comité de Protection des Personnes Ile de France I' (12/06/2018), complies with the Declaration of Helsinki and French laws and regulations, and follows the International Conference on Harmonisation E6 Guideline for Good Clinical Practice. The trial results, even if they are inconclusive, as well as biological ancillary studies will be presented at appropriate international congresses and published in international peer-review journals. TRIAL REGISTRATION NUMBER: EudraCT 2017-001165-24, NCT03643133.

Incorporating individual historical controls and aggregate treatment effect estimates into a Bayesian survival trial: a simulation study.

BACKGROUND: Performing well-powered randomised controlled trials (RCTs) of new treatments for rare diseases is often infeasible. However, with the increasing availability of historical data, incorporating existing information into trials with small sample sizes is appealing in order to increase the power. Bayesian approaches enable one to incorporate historical data into a trial's analysis through a prior distribution. METHODS: Motivated by a RCT intended to evaluate the impact on event-free survival of mifamurtide in patients with osteosarcoma, we performed a simulation study to evaluate the impact on trial operating characteristics of incorporating historical individual control data and aggregate treatment effect estimates. We used power priors derived from historical individual control data for baseline parameters of Weibull and piecewise exponential models, while we used a mixture prior to summarise aggregate information obtained on the relative treatment effect. The impact of prior-data conflicts, both with respect to the parameters and survival models, was evaluated for a set of pre-specified weights assigned to the historical information in the prior distributions. RESULTS: The operating characteristics varied according to the weights assigned to each source of historical information, the variance of the informative and vague component of the mixture prior and the level of commensurability between the historical and new data. When historical and new controls follow different survival distributions, we did not observe any advantage of choosing a piecewise exponential model compared to a Weibull model for the new trial analysis. However, we think that it remains appealing given the uncertainty that will often surround the shape of the survival distribution of the new data. CONCLUSION: In the setting of Sarcome-13 trial, and other similar studies in rare diseases, the gains in power and accuracy made possible by incorporating different types of historical information commensurate with the new trial data have to be balanced against the risk of biased estimates and a possible loss in power if data are not commensurate. The weights allocated to the historical data have to be carefully chosen based on this trade-off. Further simulation studies investigating methods for incorporating historical data are required to generalise the findings.

[Muramyldipeptide - based compounds in current medicine: focus on glucosaminylmuramyl dipeptide].

The role of immune mechanisms in the pathogenesis of almost all human diseases shown in recent decades, increase in antibiotic resistance and secondary immunodeficiency, aging of the population and widespread use of immunosuppressive drugs and procedures suggest a wider use of immunomodulators in current clinical practice, but the use of most of them limits the lack of knowledge. The most promising compounds for the development as immunomodulating agents and adjuvants for a wide range of vaccines are low molecular weight fragments of peptidoglycan - muramylpeptides. The article describes the mechanisms of action of muramylpeptides, their biological effects and properties of medicines developed on their basis. Special emphasis is placed to glucosaminylmuramyl dipeptide registered in the Russian Federation under the trade name Likopid, which is currently the best - studied drug in its group. The results of Likopid studies when used as a prophylactic and therapeutic agent for infections of various localization in adults and children, for oncological diseases and complications of chemotherapy and radiation therapy, psoriasis, atopic and other diseases are presented. It is emphasized that in diseases associated with human papillomavirus and plaque psoriasis, according to current criteria of evidence - based medicine, Likopid should be classified as drug with level A efficacy (high efficiency in 80-100% of patients). High safety of Likopid in adults and children, including newborns, is noted.

The Efficiency and Toxicity of Mifamurtide in Childhood Osteosarcoma.

The aim of the present study was to evaluate the efficiency and side effects of mifamurtide in childhood osteosarcoma (OS). In total, 477 doses of 2 mg/m intravenous (IV) mifamurtide, along with paracetamol as a premedication, were given to 15 patients with primary nonmetastatic OS after complete surgical resection and to 3 patients with progressive OS. The most common side effects encountered in the patients were chills and fever (17/18). These reactions were observed in 4 patients during the administration of each dose, in a single patient during the last administration, and in the remaining 12 patients during the first or initial 2 administrations. Headache, myalgia, and arthralgia were observed in 2 patients during each infusion. Headache was observed in 1 patient with additional hearing loss during the first 2 infusions. One patient had back pain occuring within the first infusion. Of the 15 patients with primary nonmetastatic OS and treated with the addition of mifamurtide to chemotherapy, 13 showed a complete remission, and 2 patients were still under treatment with a complete remission. Of 3 patients with progressive disease, 2 died while the disease progressed further in the third case over a 51-month period. The 3-year overall survival and event-free survival distributions were 87.5% (mean follow-up time, 46.12; 95% confidence interval, 37.79-52.45 mo) and 75.6% (mean follow-up time, 31.30; 95% confidence interval, 26.54-36.06 mo), respectively. We consider that mifamurtide therapy is a safe and well-tolerated agent in childhood OS.

Pharmacokinetics of lipid-drug conjugates loaded into liposomes.

Drugs that are neither lipophilic nor suitable for encapsulation via remote loading procedures are generally characterized by low entrapment efficiencies and poor retention in liposomes. One approach to circumvent this problem consists in covalently linking a lipid to the drug molecule in order to permit its insertion into the vesicle membrane. The nature of the conjugated lipid and linker, as well as the composition of the liposomal bilayer were found to have a profound impact on the pharmacokinetic properties and biodistribution of the encapsulated drugs as well as on their biological activity. This contribution reviews the past and recent developments on liposomal lipid-drug conjugates, and discusses important issues related to their stability and in vivo performance. It also provides an overview of the data that were generated during the clinical assessment of these formulations. The marketing authorization of the immunomodulating compound mifamurtide in several countries as well as the promising results obtained with the lipid prodrug of mitomycin C suggest that carefully designed liposomal formulations of lipid-drug conjugates is a valid strategy to improve a drug's pharmacokinetic profile and with that its therapeutic index and/or efficacy.

Salutaxel, a Conjugate of Docetaxel and a Muramyl Dipeptide (MDP) Analogue, Acts as Multifunctional Prodrug That Inhibits Tumor Growth and Metastasis.

Salutaxel (3) is a conjugate of docetaxel (7) and a muramyl dipeptide (MDP) analogue. Docetaxel (7) has been recognized as a highly active chemotherapeutic agent against various cancers. MDP and its analogues are powerful potentiators of the antitumor actions of various tumor-necrotizing agents. This article documents the discovery of compound 3 and presents pharmacological proof of its biological function in tumor-bearing mice. Drug candidate 3 was superior to compound 7 in its ability to prevent tumor growth and metastasis. Compound 3 suppressed myeloid-derived suppressor cell (MDSC) accumulation in the spleens of tumor-bearing mice and decreased various serum inflammatory cytokines levels. Furthermore, compound 3 antagonized the nucleotide-binding oligomerization domain-like receptor 1 (NOD1) signaling pathway both in vitro and in vivo.

Effectiveness of mifamurtide in addition to standard chemotherapy for high-grade osteosarcoma: a systematic review.

BACKGROUND: Osteosarcoma mostly occurs during the period of rapid bone growth in children and adolescents as high-grade osteosarcomas. Current treatment recommended for high-grade non-metastatic and metastatic and/or relapsed osteosarcoma involves neoadjuvant multiagent conventional chemotherapy, followed by surgical resection of macroscopically detected tumor and postoperative adjuvant chemotherapy. However, residual micrometastatic deposits that develop following surgery have shown resistance to postoperative/adjuvant chemotherapy. Therefore, there is a critical need for more effective and innovative therapeutic approaches such as immune stimulatory agents. The most extensively studied immune stimulatory agent in the treatment of osteosarcoma is mifamurtide. The aim of this systematic review was to identify and synthesize the evidence on the effectiveness of mifamurtide in addition to standard chemotherapy on survival outcomes. OBJECTIVES: To present the best available evidence on the treatment of high-grade non-metastatic and metastatic osteosarcoma with mifamurtide in addition to standard chemotherapy. INCLUSION CRITERIA TYPES OF PARTICIPANTS: All populations of patients regardless of age, gender or ethnicity with high-grade, resectable, non-metastatic and metastatic osteosarcoma based on histological diagnosis. TYPES OF INTERVENTIONS AND COMPARATORS: This review focused on intravenous infusion of either of the pharmaceutical formulations of mifamurtide (MTP-PE or L-MTP-PE) in addition to standard chemotherapy, and the comparator was chemotherapy alone. TYPES OF STUDIES: This review considered any experimental study design including randomized controlled trials, non-randomized trials and quasi-experimental studies. OUTCOMES: The primary outcomes of interest were event-free survival, overall survival and recurrence of osteosarcoma. Secondary outcomes that were considered included health-related quality of life and any mifamurtide-related adverse events. SEARCH STRATEGY: A search for published and unpublished literature in English was undertaken (seven published literature databases, four unpublished literature databases, and three government agency and organizational websites were searched). Studies published between 1990 to June 2016 were considered. A three-step strategy was developed using MeSH terminology and keywords to ensure that all relevant studies were included related to this review. METHODOLOGICAL QUALITY: The methodological quality of included studies was assessed by two reviewers, who appraised each study independently, using a standardized Joanna Briggs Institute (JBI) critical appraisal tool. DATA EXTRACTION: Data was extracted from the studies that were identified as meeting the criteria for methodological quality using the standard JBI data extraction tool. DATA SYNTHESIS: Due to the heterogeneity of populations and interventions in available studies, meta-analysis was not possible and results are presented in narrative form. RESULTS: Three papers outlining two studies involving 802 patients evaluated the effectiveness of mifamurtide in addition of chemotherapy. Results indicated no significant difference in event-free survival between the addition of mifamurtide to standard chemotherapy regimen and chemotherapy alone, both in non-metastatic and metastatic osteosarcoma patients. There was a significant difference in progression-free survival favoring the addition of mifamurtide in pulmonary metastatic and/or relapsed osteosarcoma. There was no significant difference in overall survival between the addition of mifamurtide and chemotherapy alone in metastatic osteosarcoma; however there was a significant difference favoring the addition of mifamurtide in non-metastatic osteosarcoma patients. The addition of mifamurtide resulted in a significant difference in survival after relapse in pulmonary metastatic and/or relapsed osteosarcoma patients. Both studies reported on mifamurtide-related adverse events - the first was reported as toxicity which included haematological, hepatic, renal, gastrointestinal disorders, cardiac, rhythm and nervous system disorders, ear disorders and others (infection, fever; and performance status) in metastatic osteosarcoma patients. Results were similar across all combined treatment regimens. Although no statistical analysis was undertaken, the figures suggest there were no significant differences between the treatment regimens. In the other study, mifamurtide-related adverse events were reported as clinical toxic effects of mifamurtide in relapsed osteosarcoma, which included chills, fever and headache for the initial dose of mifamurtide, while for the subsequent doses of mifamurtide all patients reported toxicity as delayed fatigue. CONCLUSIONS: The available evidence on the effectiveness of mifamurtide in addition to a standard chemotherapy regimen for the treatment of high-grade osteosarcoma is limited and therefore no definitive conclusions can be made.

The Role of Mifamurtide in Chemotherapy-induced Osteoporosis of Children with Osteosarcoma.

BACKGROUND: Osteosarcoma is the most frequent malignant bone tumor in childhood and young adulthood. Long-term survivors of osteosarcoma patients show high prevalence of osteoporosis and fractures. The immunomodulatory mifamurtide, which modulates macrophages activity, improves disease outcome. OBJECTIVE: To evaluate the role of mifamurtide on macrophage component of bone, the osteoclasts, during chemotherapy in children with osteosarcoma. METHOD: Osteoclasts, obtained from peripheral blood cells of healthy donors were harvested in the presence or not of mifamurtide. Moreover, osteoclast cultures were obtained from osteosarcoma patients, at onset and during chemotherapy, alone or with mifamurtide. Pro-osteoporotic tartrateresistant acid phosphatase (TRAP), phosphokinase-ß-2 (PKCß2), vanilloid receptor type 1 (TRPV1), and anti-osteoporotic cannabinoid receptor type 2 (CB2) biomarkers were analyzed by bio-molecular (qPCR), biochemical (Western Blotting), and morphological (TRAP assay) approaches. RESULTS: Osteoclasts from osteosarcoma patients show significant increase of TRAP and decrease of CB2 with respect to osteoclasts from healthy donors. This osteoclast hyperactivity is more evident in osteoclasts from osteosarcoma patients during chemotherapy. Mifamurtide reduces pro-osteoporotic TRAP, PKCß2, TRPV1 levels and increases CB2 in osteoclasts from healthy donors. Moreover, chemotherapy-induced effects on bone resorption markers are fully reverted in osteoclasts derived from osteosarcoma patients in chemotherapy plus mifamurtide. CONCLUSION: Our data suggest a new therapeutic role for mifamurtide as possible anti-resorption agent in chemotherapy-induced osteoporosis in children with osteosarcoma.

Targeting cells of the immune system: mannosylated HPMA-LMA block-copolymer micelles for targeting of dendritic cells.

BACKGROUND: Successful tumor immunotherapy depends on the induction of strong and sustained tumor antigen-specific immune responses by activated antigen-presenting cells (APCs) such as dendritic cells (DCs). Since nanoparticles have the potential to codeliver tumor-specific antigen and DC-stimulating adjuvant in a DC-targeting manner, we wanted to assess the suitability of mannosylated HPMA-LMA block polymers for immunotherapy. MATERIALS & METHODS: Fluorescence-labeled block copolymer micelles derived from P(HPMA)-block-P(LMA) copolymers and according statistical copolymers were synthesized via RAFT polymerization, and loaded with the APC activator L18-MDP. Both types of copolymers were conjugated with D-mannose to target the mannose receptor as expressed by DCs and macrophages. The extent and specificity of micelle binding and activation of APCs was monitored using mouse spleen cells and bone marrow-derived DC (BMDC). RESULTS: Nontargeting HPMA-LMA statistical copolymers showed strong unspecific cell binding. HPMA-LMA block copolymers bound DC only when conjugated with mannose, and in a mannose receptor-specific manner. Mannosylated HPMA-LMA block copolymers were internalized by DC. DC-targeting HPMA-LMA block copolymers mediated DC activation when loaded with L18-MDP. CONCLUSION: Mannosylated HPMA-LMA block copolymers are a promising candidate for the delvopment of DC-targeting nanovaccines.

Innate immunity: Bacterial cell-wall muramyl peptide targets the conserved transcription factor YB-1.

The bacterial cell wall muramyl dipeptides MDP and glucosaminyl-MDP (GMDP) are powerful immunostimulators but their binding target remains controversial. We previously reported expression cloning of GMDP-binding polypeptides and identification of Y-box protein 1 (YB-1) as their sole target. Here we show specific binding of GMDP to recombinant YB-1 protein and subcellular colocalization of YB-1 and GMDP. GMDP binding to YB-1 upregulated gene expression levels of NF-κB2, a mediator of innate immunity. Furthermore, YB-1 knockdown abolished GMDP-induced Nfkb2 expression. GMDP/YB-1 stimulation led to NF-κB2 cleavage, transport of activated NF-κB2 p52 to the nucleus, and upregulation of NF-κB2-dependent chemokine Cxcr4 gene expression. Therefore, our findings identify YB-1 as new target for muramyl peptide signaling.

Symptomatic males and female carriers in a large Caucasian kindred with XIAP deficiency.

PURPOSE: X-linked inhibitor of apoptosis (XIAP) deficiency caused by mutations in BIRC4 was originally described in male patients with X-linked lymphoproliferative syndrome type 2 (XLP2). Recent observations have highlighted a critical role of XIAP for the regulation of NOD2 signaling and are probably the molecular basis for increasingly recognized further immune dysregulatory symptoms of XIAP deficient patients, such as inflammatory bowel disease (IBD). We describe a large Caucasian family in which IBD and erythema nodosum (EN) also manifested in female carriers of XIAP mutations. METHODS: Clinical data and laboratory findings including flow cytometric analysis of XIAP protein expression and sequencing of the BIRC4 gene. NOD2 signaling was investigated by determination of TNFα production in monocytes upon L18-MDP stimulation in vitro. RESULTS: The BIRC4 nonsense mutation p.P225SfsX226 was identified as the genetic cause of XIAP deficiency in our family. Surprisingly, clinical symptoms were not restricted to male patients, but also occurred in several female carriers. The most severely affected carrier demonstrated random X-inactivation, leading to a significant expression of mutated XIAP protein in monocytes, and consequently to impaired NOD2 responses in vitro. CONCLUSION: Our report provides further evidence that clinical symptoms of XIAP deficiency are not restricted to male patients. Random X-inactivation may be associated with EN and mild IBD also in female carriers of BIRC4 mutations. Analysis of the X-inactivation pattern reflected by XIAP protein expression can identify such carriers and the analysis of NOD2 signaling by flow cytometry can confirm the functional significance. XIAP expression patterns should be investigated in female patients with a family history of EN and/or IBD.

Lifetime effectiveness of mifamurtide addition to chemotherapy in nonmetastatic and metastatic osteosarcoma: a Markov process model analysis.

The mortality and progression rates in osteosarcoma differ depending on the presence of metastasis. A decision model would be useful for estimating long-term effectiveness of treatment with limited clinical trial data. The aim of this study was to explore the lifetime effectiveness of the addition of mifamurtide to chemotherapy for patients with metastatic and nonmetastatic osteosarcoma. The target population was osteosarcoma patients with or without metastasis. A Markov process model was used, whose time horizon was lifetime with a starting age of 13 years. There were five health states: disease-free (DF), recurrence, post-recurrence disease-free, post-recurrence disease-progression, and death. Transition probabilities of the starting state, DF, were calculated from the INT-0133 clinical trials for chemotherapy with and without mifamurtide. Quality-adjusted life-years (QALY) increased upon addition of mifamurtide to chemotherapy by 10.5 % (10.13 and 9.17 QALY with and without mifamurtide, respectively) and 45.2 % (7.23 and 4.98 QALY with and without mifamurtide, respectively) relative to the lifetime effectiveness of chemotherapy in nonmetastatic and metastatic osteosarcoma, respectively. Life-years gained (LYG) increased by 10.1 % (13.10 LYG with mifamurtide and 11.90 LYG without mifamurtide) in nonmetastatic patients and 42.2 % (9.43 LYG with mifamurtide and 6.63 LYG without mifamurtide) in metastatic osteosarcoma patients. The Markov model analysis showed that chemotherapy with mifamurtide improved the lifetime effectiveness compared to chemotherapy alone in both nonmetastatic and metastatic osteosarcoma. Relative effectiveness of the therapy was higher in metastatic than nonmetastatic osteosarcoma over lifetime. However, absolute lifetime effectiveness was higher in nonmetastatic than metastatic osteosarcoma.