Advancing personalized medicine in brain cancer: exploring the role of mRNA vaccines.

Advancing personalized medicine in brain cancer relies on innovative strategies, with mRNA vaccines emerging as a promising avenue. While the initial use of mRNA vaccines was in oncology, their stunning success in COVID-19 resulted in widespread attention, both positive and negative. Regardless of politically biased opinions, which relate more to the antigenic source than form of delivery, we feel it is important to objectively review this modality as relates to brain cancer. This class of vaccines trigger robust immune responses through MHC-I and MHC-II pathways, in both prophylactic and therapeutic settings. The mRNA platform offers advantages of rapid development, high potency, cost-effectiveness, and safety. This review provides an overview of mRNA vaccine delivery technologies, tumor antigen identification, combination therapies, and recent therapeutic outcomes, with a particular focus on brain cancer. Combinatorial approaches are vital to maximizing mRNA cancer vaccine efficacy, with ongoing clinical trials exploring combinations with adjuvants and checkpoint inhibitors and even adoptive cell therapy. Efficient delivery, neoantigen identification, preclinical studies, and clinical trial results are highlighted, underscoring mRNA vaccines' potential in advancing personalized medicine for brain cancer. Synergistic combinatorial therapies play a crucial role, emphasizing the need for continued research and collaboration in this area.

Retraction Note to: Stromal vascular fraction cells for the treatment of critical limb ischemia: a pilot study.

The Editor-in-Chief and the publisher have retracted this article [1]. An investigation by the Lithuanian Bioethics Committee concluded that, contrary to the statements in the article, the study described was not conducted in the Vilnius City Clinical Hospital and the Commission of Medical Ethics did not issue any approval for such a study.

Isolation of clinically relevant concentrations of bone marrow mesenchymal stem cells without centrifugation.

BACKGROUND: This study examined the quality of bone marrow aspirates extracted using a novel, FDA cleared method to optimally target cells from the inner cortical iliac bone surface without the need for centrifugation. This method employs small draws from a single puncture that promote only lateral flow from multiple sites (SSLM method). The study utilized the Marrow Cellutions bone marrow aspiration system (MC system) which is based on the SSLM method and compared the MC system directly to bone marrow concentrates (BMAC) generated by centrifugation of aspirates harvested with a standard aspiration needle. METHODS: Three direct comparisons were conducted evaluating the SSLM draws and BMACs derived from the same patient from contralateral iliac crests. The levels of TNCs/mL, CD34+ cells/mL, CD117+ cells/mL, and CFU-f/mL were compared between the various bone marrow preparations. The cellular content of a series of SSLM draws was also analyzed to determine the total nucleated cell (TNC) count and the concentration of mesenchymal stem/progenitor cells as measured by colony forming unit fibroblasts (CFU-f). RESULTS: In direct comparisons with BMAC systems, SSLM draws yielded significantly higher CFU-f concentrations and comparable concentrations of CD34+ and CD117+ cells. In addition, the average quantity of TNCs/mL in a series of 30 patients utilizing the SSLM draw was 35.2 × 106 ± 17.1 × 106 and the average number of CFU-f/mL was 2885 ± 1716. There were small but significant correlations between the TNCs/mL and the CFU-fs/mL using the SSLM method as well as between the age of the patient and the CFU-fs/mL. CONCLUSIONS: The MC Device, using the SSLM draw technique, produced concentrations of CFU-fs, CD34+ cells and CD117+ cells that were comparable or greater to BMACs derived from the same patient. Given the rapid speed and simplicity of the MC Device, we believe this novel system possesses significant practical advantages to other currently available centrifugation based systems.

A new cancer immunotherapy via simultaneous DC-mobilization and DC-targeted IDO gene silencing using an immune-stimulatory nanosystem.

The activity of negative immune regulatory molecules, such as indoleamine 2,3-oxygenase (IDO), significantly attenuates DC (Dendritic cells)-mediated immunotherapy. We have previously reported that knockdown of IDO using siRNA can reinstall anti-tumor immunity. However, a DC-targeted siRNA delivery system for in vivo mobilized DCs remains to be developed, while gene silencing in mobilized DCs for cancer immunotherapy has never been explored. In our study, we developed a novel DC-targeted siRNA delivery system, man-GNR-siIDO, using as a nanocarrier of siRNA specific for IDO (siIDO) and mannose (man) as a guide molecule for targeting DCs. We explored the immunostimulatory man-GNR-siIDO nano-construct in DCs mobilized by Flt3-L, a receptor-type tyrosine kinase ligand, for lung cancer immunotherapy. In vivo DC-targeted gene silencing of IDO resulted in robust anti-tumor immunity as evidenced by promoting DC maturation, up-regulating tumor antigen-specific T-cell proliferation and enhancing tumor-specific cytotoxicity. A combinatorial treatment for Lewis Lung Carcinoma (LLC)-bearing mice, with man-GNR-siIDO and Flt3-L, significantly attenuated tumor growth and delayed tumor formation, suggesting the treatment feasibility of the man-GNR-siIDO system in Flt3-L mobilized DCs in the immunotherapy of lung cancer. Therefore, our study highlights a clinical potential for a first-in-class anti-cancer immunotherapy through simultaneous DC-mobilization and DC-targeted gene silencing of IDO with man-GNR-siIDO and Flt3-L treatments.

Fibroblasts as a practical alternative to mesenchymal stem cells.

Mesenchymal stem cell (MSC) therapy offers great potential for treatment of disease through the multifunctional and responsive ability of these cells. In numerous contexts, MSC have been shown to reduce inflammation, modulate immune responses, and provide trophic factor support for regeneration. While the most commonly used MSC source, the bone marrow provides relatively little starting material for cellular expansion, and requires invasive extraction means, fibroblasts are easily harvested in large numbers from various biological wastes. Additionally, in vitro expansion of fibroblasts is significantly easier given the robustness of these cells in tissue culture and shorter doubling time compared to typical MSC. In this paper we put forward the concept that in some cases, fibroblasts may be utilized as a more practical, and potentially more effective cell therapy than mesenchymal stem cells. Anti-inflammatory, immune modulatory, and regenerative properties of fibroblasts will be discussed in the context of regenerative medicine.

Symptomatic anterior cruciate ligament tears treated with percutaneous injection of autologous bone marrow concentrate and platelet products: a non-controlled registry study.

BACKGROUND: Bone marrow concentrate (BMC) has shown promise in the treatment of several orthopedic conditions. This registry study investigated the use of autologous BMC and platelet products for percutaneous anterior cruciate ligament (ACL) treatment. METHODS: Twenty-nine patients presenting to a single outpatient interventional musculoskeletal and pain practice with symptomatic grade 1, 2, or 3 ACL tears with less than 1 cm retraction were enrolled. Patients were treated with a percutaneous ACL injection of autologous BMC and platelet products using fluoroscopic guidance. Pre- and post-treatment magnetic resonance imaging analysis was completed for 23 patients using ImageJ software for an objective quantitative analysis of pixel density as a proxy for ACL integrity. Subjective clinical outcome measures collected pre-treatment and at 1, 3, 6, 12, 18, 24, and 36 months post-treatment include the Numerical Pain Scale (NPS), the Lower Extremity Functional Scale (LEFS), the International Knee Documentation Committee (IKDC) form, and a modified version of the Single Assessment Numeric Evaluation. RESULTS: Seventy-seven percent of patients treated with BMC injections into the ACL showed significant improvement (p < 0.01) in objective measures of ACL integrity at an average of 8.8 months (median 4.7 months). The mean of last patient-reported improvement was 72% (SD = 35) at an average of 23 (SD = 10) months post-treatment. Mean scores were found to be significantly different (p < 0.05) for the NPS at 6, 18, and 24 months, and LEFS and IKDC at all time points (i.e. 1, 3, 6, 12, 18, 24, and 36 months) relative to baseline. CONCLUSION: In symptomatic patients with grade 1, 2, or even grade 3 tears with minimal retraction, ACL treatment with percutaneous injection of BMC and platelet products shows promise as a non-surgical alternative. However, a larger randomized controlled trial is warranted to confirm these findings. Trial registration NCT03011398. A Clinical Registry of Orthobiologics Procedures. https://clinicaltrials.gov/ct2/show/NCT03011398?term=orthobiologics&rank=1 . Registered 29 December 2016. Enrollment 1 December 2011-retrospectively registered.

Unleashing endogenous TNF-alpha as a cancer immunotherapeutic.

Tumor necrosis factor (TNF)-alpha was originally identified in the 1970s as the serum mediator of innate immunity capable of inducing hemorrhagic necrosis in tumors. Today, a wide spectrum of biological activities have been attributed to this molecule, and clinical translation has mainly occurred not in using it to treat cancer, but rather to inhibit its effects to treat autoimmunity. Clinical trials utilizing systemic TNF-alpha administration have resulted in an unacceptable level of toxicities, which blocked its development. In contrast, localized administration of TNF-alpha in the form of isolated limb perfusion have yielded excellent results in soft tissue sarcomas. Here we describe a novel approach to leveraging the potent antineoplastic activities of TNF-alpha by enhancing activity of locally produced TNF-alpha through extracorporeal removal of soluble TNF-alpha receptors. Specifically, it is known that cancerous tissues are infiltrated with monocytes, T cells, and other cells capable of producing TNF-alpha. It is also known that tumors, as well as cells in the tumor microenvironment produce soluble TNF-alpha receptors. The authors believe that by selectively removing soluble TNF-alpha receptors local enhancement of endogenous TNF-alpha activity may provide for enhanced tumor cell death without associated systemic toxicities.

A specific protocol of autologous bone marrow concentrate and platelet products versus exercise therapy for symptomatic knee osteoarthritis: a randomized controlled trial with 2 year follow-up.

BACKGROUND: Cell-based therapies have shown promise for the treatment of knee osteoarthritis (OA). The current study compared exercise therapy to autologous bone marrow concentrate (BMC) and platelet products for knee OA treatment. METHODS: Patients with symptomatic knee OA (N = 48) were randomized into either an exercise therapy control group or treatment group with injection of autologous BMC and platelet products. Patients in the control group could crossover to BMC treatment after 3 months. Clinical outcomes were documented at baseline and at 6-weeks, 3, 6, 12 and 24 months, including the Knee Society Score (KSS), Pain Visual Analogue Scale, Short Form-12 Scales (SF-12), and Lower Extremity Activity Scale (LEAS). RESULTS: All patients in the exercise group crossed over to receive BMC treatment after 3 months (N = 22 crossover). At 3 months, KSS-knee, SF-12 Physical, and LEAS improved significantly in the crossover group compared to exercise, similar to significant improvements on KSS-knee and LEAS for the treatment group (N = 26) compared to exercise group at 3 months. After BMC treatment, patients' clinical outcome scores (except SF-12 Mental Health), were significantly improved through the 2-year follow-up compared to baseline. No serious adverse events were reported. CONCLUSION: The use of image-guided percutaneous BMC with platelet products yielded better results than exercise therapy as an effective alternative therapy for patients with symptomatic moderate to moderate-severe osteoarthritis of the knee. Trial registration NCT02034032. https://clinicaltrials.gov/ct2/show/NCT02034032 . Registered 13 January 2014.

Effect of Infla-Kine supplementation on the gene expression of inflammatory markers in peripheral mononuclear cells and on C-reactive protein in blood.

BACKGROUND: Chronic inflammation is a predisposing factor to numerous degenerative diseases including cancer, heart failure and Alzheimer's disease. Infla-Kine is a natural supplement comprised of a proprietary blend of Lactobacillus fermentum extract, burdock seed (arctigenin), zinc, alpha lipoic acid, papaya enzyme and an enhanced absorption bio-curcumin complex (BCM-95®). METHODS: Infla-Kine was administered twice daily to 24 health volunteers for 4 weeks. Quantitative RT-PCR was used to assess mRNA transcripts of IL-1b, IL8, IL-6, NF-κB, and TNF-α from peripheral blood mononuclear cells (PBMC). C reactive protein (CRP) was measured from serum. Additionally, quality of life questionnaires were employed to assess general feeling of well-being. Assessments were made before treatment and at conclusion of treatment (4 weeks). RESULTS: As compared to pre-treatment, after 4 weeks, a statistically significant reduction of IL8, IL-6, NF-κB, and TNF-α transcripts was observed in PBMC. Furthermore, reduction of IL-1b transcript and serum CRP was observed but did not reach statistical significance. Quality of life improvements were most prevalent in muscle and joint pains. CONCLUSIONS: Overall, our data demonstrate that twice daily administration of Infla-Kine for 4 weeks reduces inflammatory markers and quality of life in healthy volunteers.

Xenon in the treatment of panic disorder: an open label study.

BACKGROUND: Current treatments of panic disorder (PD) are limited by adverse effects, poor efficacy, and need for chronic administration. The established safety profile of subanesthetic concentrations of xenon gas, which is known to act as a glutamate subtype NMDA receptor antagonist, coupled with preclinical studies demonstrating its effects in other anxiety related conditions, prompted us to evaluate its feasibility and efficacy in treatment of patients with PD. METHODS: An open-label clinical trial of xenon-oxygen mixture was conducted in 81 patients with PD; group 1 consisting of patients only with PD (N = 42); and group 2 patients with PD and other comorbidities (N = 39). RESULTS: Based on the analysis of the results of a number of psychometric scales used in this study (SAS, HADS, CGI), several conclusions can be made: (1) xenon is a potentially effective modality in acute treatment of PD; (2) an anti-panic effect of xenon administration persists for at least 6 months after the completion of the active phase of treatment; (3) xenon inhalation is well tolerated, with the drop-out rates being much lower than that of conventional pharmacotherapy (5.8% vs. 15%); (4) the severity of depressive disorders that frequently accompany PD can be significantly reduced with the use of xenon; (5) xenon may be considered as an alternative to benzodiazepines in conjunction with cognitive-behavioral therapy as a safe modality in treatment of anxiety disorder. CONCLUSIONS: These data support the need for randomized double-blind clinical trials to further study xenon-based interventions. Trial registration This clinical trial was retrospectively registered on April 14th, 2017 as ISRCTN15184285 in the ISRCTN database.

Intra-articular injection in the knee of adipose derived stromal cells (stromal vascular fraction) and platelet rich plasma for osteoarthritis.

BACKGROUND: Stromal vascular fraction (SVF) can easily be obtained from a mini-lipoaspirate procedure of fat tissue and platelet rich plasma (PRP) can be obtained from peripheral blood. We evaluated the safety and preliminary efficacy of administering SVF and PRP intra-articularly into patients with osteoarthritis grade 1 and 2. METHODS: A total of ten patients underwent a local tumescent liposuction procedure to remove approximately 100 ml of fat tissue from the abdomen. SVF was isolated using an enzyme digestion and resuspended in PRP for intra-articular injection in the knee. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and six-minute walk distance (6MWD) were used to evaluate clinical effects and included measure of patient's subjective assessment of pain, joint mobility, and physical disability. WOMAC score, 6MWD and laboratory tests were repeated at 3 and 6 months and 1, 1.5 and 2 years. XRAY and MRI were completed at 1 year. RESULTS: The average total WOMAC score was 64 at baseline and significantly reduced to 52 at 3 months, 46 at 6 months, 42 at 1 year, 38 at 1.5 years, and 41 at 2 years. Patients walked an average of 1310 feet at baseline and demonstrated a statistically significant improvement at 3 and 6 months and 1, 1.5, and 2 years post treatment. Cartilage thickness as determined by MRI improved by at least 0.2 mm in six patients, was unchanged in two patients and decreased by at least 0.2 mm in two patients. CONCLUSIONS: Overall, all of the patients were pleased with the treatment results. They reported a reduction in pain levels, especially after 3 months. More importantly, the procedure demonstrated a strong safety profile with no severe adverse events or complications reported. Trial registration NCT03089762; Name of registry: http://www.clinicaltrials.gov.

Treatment of lumbar degenerative disc disease-associated radicular pain with culture-expanded autologous mesenchymal stem cells: a pilot study on safety and efficacy.

BACKGROUND: Degenerative disc disease (DDD) is a common cause of lower back pain with radicular symptoms and has a significant socioeconomic impact given the associated disability. Limited effective conservative therapeutic options result in many turning to surgical alternatives for management, which vary in the rate of success and also carry an increased risk of morbidity and mortality associated with the procedures. Several animal based studies and a few human pilot studies have demonstrated safety and suggest efficacy in the treatment of DDD with mesenchymal stem cells (MSCs). The use of bone marrow-derived MSCs for the treatment of DDD is promising and in the present study we report on the safety and efficacy findings from a registry based proof of concept study using a percutaneous intradiscal injection of cultured MSCs for the management of DDD with associated radicular symptoms. METHODS: Thirty-three patients with lower back pain and disc degeneration with a posterior disc bulge diagnosed on magnetic resonance imaging (MRI) met the inclusion criteria and were treated with culture-expanded, autologous, bone marrow-derived MSCs. Prospective registry data was obtained at multiple time intervals up to 6 years post-treatment. Collected outcomes included numeric pain score (NPS), a modified single assessment numeric evaluation (SANE) rating, functional rating index (FRI), measurement of the intervertebral disc posterior dimension, and adverse events. RESULTS: Three patients reported pain related to procedure that resolved. There were no serious adverse events (i.e. death, infection, or tumor) associated with the procedure. NPS change scores relative to baseline were significant at 3, 36, 48, 60, and 72 months post-treatment. The average modified SANE ratings showed a mean improvement of 60% at 3 years post-treatment. FRI post-treatment change score averages exceeded the minimal clinically important difference at all time points except 12 months. Twenty of the patients treated underwent post-treatment MRI and 85% had a reduction in disc bulge size, with an average reduction size of 23% post-treatment. CONCLUSIONS: Patients treated with autologous cultured MSCs for lower back pain with radicular symptoms in the setting of DDD reported minor adverse events and significant improvements in pain, function, and overall subjective improvement through 6 years of follow-up. NCT03011398. A Clinical Registry of Orthobiologics Procedures. https://clinicaltrials.gov/ct2/show/NCT03011398?term=orthobiologics&rank=1.

Stromal vascular fraction cells for the treatment of critical limb ischemia: a pilot study.

BACKGROUND: Cell-based therapy is being explored as an alternative treatment option for critical limb ischemia (CLI), a disease associated with high amputation and mortality rates and poor quality of life. However, therapeutic potential of uncultured adipose-derived stromal vascular fraction (SVF) cells has not been evaluated as a possible treatment. In this pilot study, we investigated the efficacy of multiple injections of autologous uncultured adipose-derived SVF cells to treat patients with CLI. METHODS: This study included 15 patients, from 35 to 77 years old, with rest pain and ulceration. SVF cells were injected once or twice in the ischemic limb along the arteries. Digital subtraction angiography was performed before and after cell therapy. The clinical follow up was carried out for the subsequent 12 months after the beginning of the treatment. RESULTS: Multiple intramuscular SVF cell injections caused no complications during the follow-up period. Clinical improvement occurred in 86.7% of patients. Two patients required major amputation, and the amputation sites healed completely. The rest of patients achieved a complete ulcer healing, pain relief, improved ankle-brachial pressure index and claudication walking distance, and had ameliorated their quality of life. Digital subtraction angiography performed before and after SVF cell therapy showed formation of numerous vascular collateral networks across affected arteries. CONCLUSION: Results of this pilot study demonstrate that the multiple intramuscular SVF cell injections stimulate regeneration of injured tissue and are effective alternative to achieve therapeutic angiogenesis in CLI patients who are not eligible for conventional treatment. Trial registration number at ISRCTN registry, ISRCTN13001382. Retrospectively registered at 26/04/2017.

Experimental support for the effects of a probiotic/digestive enzyme supplement on serum cholesterol concentrations and the intestinal microbiome.

BACKGROUND: Elevated levels of blood cholesterol are associated with cardiovascular disease, a leading cause of morbidity and mortality worldwide. Current therapies for addressing elevated blood cholesterol can be inadequate, ineffective or associated with side effects; therefore, the search for additional therapies is ongoing. This study evaluated Daily Body Restore (DBR), a proprietary blend of 9 probiotic organisms of the genera Lactobacillus and Bifidobacterium, and 10 digestive enzymes, for its effects on cholesterol metabolism using an in vitro system and a mouse model. METHODS: We used a murine model of hypercholesterolemia induced by a high fat diet to evaluate the effects of DBR on blood cholesterol concentrations. Hypercholesterolemic mice were supplemented with DBR in their drinking water for 8 weeks and compared to control mice given low fat diets or unsupplemented high fat diets. To evaluate the effects of DBR on the activity of gut microbiota in vitro, the Shime(®) system consisting of sequential colon reactors was supplemented with DBR for analysis of short chain fatty acid production. RESULTS: Analysis of hypercholesterolemic mice after 4 and 8 weeks of DBR supplementation revealed significant decreases in blood concentrations of low-density lipoprotein (LDL) and increases in high-density lipoprotein (HDL) while triglyceride concentrations were unaltered. Specifically, after 4 weeks of DBR supplementation, there was a 47 % decrease in LDL and a 32 % increase in HDL in peripheral blood compared to unsupplemented, high fat diet-fed mice. After 8 weeks of DBR treatment, LDL concentrations were dramatically reduced by 78 % and HDL was increased by 52 % relative to control mice. Addition of DBR to the Shime(®) system led to significantly increased production of propionate in colon reactors, indicative of microbial production of short chain fatty acids known to inhibit cholesterol synthesis. CONCLUSIONS: DBR, a probiotic and digestive enzyme supplement, lowered harmful LDL and increased HDL levels in a mouse model and also exerted in vitro effects consistent with cholesterol-lowering activity. Given the magnitude of the effects of DBR, these findings are promising for clinical implementation of DBR for treating hypercholesterolemia.

Intra-discal injection of autologous, hypoxic cultured bone marrow-derived mesenchymal stem cells in five patients with chronic lower back pain: a long-term safety and feasibility study.

BACKGROUND: Chronic low back pain due to disc degeneration represents a major social and economic burden worldwide. The current standard of care is limited to symptomatic relief and no current approved therapy promotes disc regeneration. Bone marrow-derived mesenchymal stem cells (MSCs) are easily accessible and well characterized. These MSCs are multipotent and exhibit great tissue regenerative potential including bone, cartilage, and fibrous tissue regeneration. The use of this cell-based biologic for treating protruding disc herniation and/or intervertebral disc degeneration is a promising therapeutic strategy, due to their known regenerative, immuno-modulatory and anti-inflammatory properties. METHODS: Five patients diagnosed with degenerative disc disease received an intra-discal injection of autologous, hypoxic cultured, bone marrow-derived mesenchymal stem cells (15.1-51.6 million cells) as part of a previous study. These patients were re-consented to participate in this study in order to assess long-term safety and feasibility of intra-discal injection of autologous, hypoxic cultured, bone marrow-derived mesenchymal stem cells 4-6 years post mesenchymal stem cell infusion. The follow-up study consisted of a physical examination, a low back MRI, and a quality of life questionnaire. RESULTS: Patients' lower back MRI showed absence of neoplasms or abnormalities surrounding the treated region. Based on the physical examination and the quality of life questionnaire, no adverse events were reported due to the procedure or to the stem cell treatment 4-6 years post autologous, hypoxic cultured mesenchymal stem cell infusion. All patients self-reported overall improvement, as well as improvement in strength, post stem cell treatment, and four out of five patients reported improvement in mobility. CONCLUSION: This early human clinical data suggests the safety and feasibility of the clinical use of hypoxic cultured bone marrow-derived mesenchymal stem cells for the treatment of lower back pain due to degenerative disc disorders and support further studies utilizing hypoxic cultured bone marrow-derived stem cells. The overall improvements reported are encouraging, but a larger double-blind, controlled, randomized clinical study with significant number of patients and implementation of validated endpoint measurements are next steps in order to demonstrate efficacy of this cell-based biologic.

Human endometrial regenerative cells alleviate carbon tetrachloride-induced acute liver injury in mice.

BACKGROUND: The endometrial regenerative cell (ERC) is a novel type of adult mesenchymal stem cell isolated from menstrual blood. Previous studies demonstrated that ERCs possess unique immunoregulatory properties in vitro and in vivo, as well as the ability to differentiate into functional hepatocyte-like cells. For these reasons, the present study was undertaken to explore the effects of ERCs on carbon tetrachloride (CCl4)-induced acute liver injury (ALI). METHODS: An ALI model in C57BL/6 mice was induced by administration of intraperitoneal injection of CCl4. Transplanted ERCs were intravenously injected (1 million/mouse) into mice 30 min after ALI induction. Liver function, pathological and immunohistological changes, cell tracking, immune cell populations and cytokine profiles were assessed 24 h after the CCl4 induction. RESULTS: ERC treatment effectively decreased the CCl4-induced elevation of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and improved hepatic histopathological abnormalities compared to the untreated ALI group. Immunohistochemical staining showed that over-expression of lymphocyte antigen 6 complex, locus G (Ly6G) was markedly inhibited, whereas expression of proliferating cell nuclear antigen (PCNA) was increased after ERC treatment. Furthermore, the frequency of CD4+ and CD8+ T cell populations in the spleen was significantly down-regulated, while the percentage of splenic CD4+CD25+FOXP3+ regulatory T cells (Tregs) was obviously up-regulated after ERC treatment. Moreover, splenic dendritic cells in ERC-treated mice exhibited dramatically decreased MHC-II expression. Cell tracking studies showed that transplanted PKH26-labeled ERCs engrafted to lung, spleen and injured liver. Compared to untreated controls, mice treated with ERCs had lower levels of IL-1ß, IL-6, and TNF-α but higher level of IL-10 in both serum and liver. CONCLUSIONS: Human ERCs protect the liver from acute injury in mice through hepatocyte proliferation promotion, as well as through anti-inflammatory and immunoregulatory effects.

Safety of targeting tumor endothelial cell antigens.

The mechanisms underlying discrimination between "self" and "non-self", a central immunological principle, require careful consideration in immune oncology therapeutics where eliciting anti-cancer immunity must be weighed against the risk of autoimmunity due to the self origin of tumors. Whole cell vaccines are one promising immunotherapeutic avenue whereby a myriad of tumor antigens are introduced in an immunogenic context with the aim of eliciting tumor rejection. Despite the possibility collateral damage to healthy tissues, cancer immunotherapy can be designed such that off target autoimmunity remains limited in scope and severity or completely non-existent. Here we provide an immunological basis for reconciling the safety of cancer vaccines, focusing on tumor endothelial cell vaccines, by discussing the following topics: (a) Antigenic differences between neoplastic and healthy tissues that can be leveraged in cancer vaccine design; (b) The layers of tolerance that control T cell responses directed against antigens expressed in healthy tissues and tumors; and, (c) The hierarchy of antigenic epitope selection and display in response to whole cell vaccines, and how antigen processing and presentation can afford a degree of selectivity against tumors. We conclude with an example of early clinical data utilizing ValloVax™, an immunogenic placental endothelial cell vaccine that is being advanced to target the tumor endothelium of diverse cancers, and we report on the safety and efficacy of ValloVax™ for inducing immunity against tumor endothelial antigens.

Cancer anti-angiogenesis vaccines: Is the tumor vasculature antigenically unique?

Angiogenesis is essential for the growth and metastasis of solid tumors. The tumor endothelium exists in a state of chronic activation and proliferation, fueled by the tumor milieu where angiogenic mediators are aberrantly over-expressed. Uncontrolled tumor growth, immune evasion, and therapeutic resistance are all driven by the dysregulated and constitutive angiogenesis occurring in the vasculature. Accordingly, great efforts have been dedicated toward identifying molecular signatures of this pathological angiogenesis in order to devise selective tumor endothelium targeting therapies while minimizing potential autoimmunity against physiologically normal endothelium. Vaccination with angiogenic antigens to generate cellular and/or humoral immunity against the tumor endothelium has proven to be a promising strategy for inhibiting or normalizing tumor angiogenesis and reducing cancer growth. Here we review tumor endothelium vaccines developed to date including active immunization strategies using specific tumor endothelium-associated antigens and whole endothelial cell-based vaccines designed to elicit immune responses against diverse target antigens. Among the novel therapeutic options, we describe a placenta-derived endothelial cell vaccine, ValloVax™, a polyvalent vaccine that is antigenically similar to proliferating tumor endothelium and is supported by pre-clinical studies to be safe and efficacious against several tumor types.

Induction of tumor inhibitory anti-angiogenic response through immunization with interferon Gamma primed placental endothelial cells: ValloVax™.

BACKGROUND: While the concept of angiogenesis blockade as a therapeutic intervention for cancer has been repeatedly demonstrated, the full promise of this approach has yet to be realized. Specifically, drugs such as VEGF-blocking antibodies or kinase inhibitors suffer from the drawbacks of resistance development, as well as off-target toxicities. Previous studies have demonstrated feasibility of specifically inducing immunity towards tumor endothelium without consequences of systemic autoimmunity in both animal models and clinical settings. METHOD: Placenta-derived endothelial cells were isolated and pretreated with interferon gamma to enhance immunogenicity. Syngeneic mice received subcutaneous administration of B16 melanoma, 4 T1 mammary carcinoma, and Lewis Lung Carcinoma (LLC), followed by administration of control saline, control placental endothelial cells, and interferon gamma primed endothelial cells (ValloVax™). Tumor volume was quantified. An LLC metastasis model was also established and treated under similar conditions. Furthermore, a safety analysis in non-tumor bearing mice bracketing the proposed clinical dose was conducted. RESULTS: ValloVax™ immunization led to significant reduction of tumor growth and metastasis as compared to administration of non-treated placental endothelial cells. Mitotic inactivation by formalin fixation or irradiation preserved tumor inhibitory activity. Twenty-eight day evaluation of healthy male and female mice immunized with ValloVax™ resulted in no abnormalities or organ toxicities. CONCLUSION: Given the established rationale behind the potential therapeutic benefit of inhibiting tumor angiogenesis as a treatment for cancer, immunization against a variety of endothelial cell antigens may produce the best clinical response, enhancing efficacy and reducing the likelihood of the development of treatment resistance. These data support the clinical evaluation of irradiated ValloVax™ as an anti-angiogenic cancer vaccine.