Retraction of 'Triple-responsive inorganic-organic hybrid microcapsules as a biocompatible smart platform for the delivery of small molecules' by Alexander S. Timin et al., J. Mater. Chem. B, 2016, 4, 7270-7282, https://doi.org/10.1039/C6TB02289H.

Background. The gene therapy based on hematopoietic cell xenotransplantation is becoming a powerful and universally applied therapeutic strategy in an ever-expanding range of human diseases. One of the current issues in implementing the techniques of genome modification in hematopoietic stem cells (HSCs) into clinical practice is to assure the quality and safety of gene and cell therapy products for human use. This is achieved by animal model testing at the stage of preclinical studies. With this purpose in view, NBSGW mice seem to be a unique and promising model for human HSC engraftment without pre-conditioning. Aim. To test the NBSGW mouse model for human HSC engraftment, to optimize the methods of assessing the state of the animals and monitoring the chimerism level for translational preclinical development of HSC-based products for gene and cell therapy. Materials & Methods. The xenograft models of NBSGW mice were generated using the samples of the selected peripheral blood CD34+ HSCs from a healthy donor. Serial transplantation was performed by intravenous injection of bone marrow cells from primary recipients with a high chimerism level. Engraftment efficiency was evaluated by flow cytofluorometry (FCF) and droplet digital PCR (ddPCR). Subpopulation pattern of human cell engraftment was assessed by FCF. Results. The tested HSC transplantation regimen is characterized by favorable toxicity profile. In the entire study sample of mice, the FCF analysis showed a long-term engraftment of human cells with a high chimerism level (23.5–93.6 %) in the bone marrow of the animals, also after serial transplantation, which was confirmed by ddPCR. The B-lineage differentiation cells predominated in all tested samples (of peripheral blood, bone marrow, and spleen) from mice after primary and serial transplantation. The ddPCR assay can be used as an additional tool for validating the level of human cell engraftment determined by FCF. Conclusion. NBSGW mice present a promising reference model for preclinical development of gene and cell therapy products based on human primary HSCs with a modified genome.

The chemokine receptor CCR5, encoded by appropriate gene, is expressed by CD4+ cells, being a membrane co-receptor for HIV-1.Homozygous carriers of CCR5 mutation (CCR5-Δ32 deletion) are resistant to HIV-1 infection.The heterozygous mutation (hetero-CCR5-Δ32) does not affect susceptibility, but such patients have a late onset of AIDS.The role of this heterozygous mutation is unclear in HIV-infected individuals with lymphomas.Hence, the purpose of our study was to evaluate the impact of carrying hetero-CCR5-Δ32 on the epidemiology and course of lymphoma in patients with HIV infection, as well as the impact on treatment outcomes.We studied 39 patients with lymphomas and HIV, for whom the CCR5 gene mutation status was determined.We identify the five (13%) HIV-infected patients with lymphomas who had a heterozygous mutation of CCR5 gene (hetero-CCR5-Δ32), others -34 (87%) HIV-infected patients with lymphomas had wild-type genotype (WT/WT).We observed the significant prevalence of Burkitt lymphoma in hetero-CCR5-Δ32 cohort, but no difference in clinical course and outcomes of the lymphomas.We may assume that heterozygous mutation of CCR5 gene predisposes for delayed progression from HIV infection to AIDS among infected individuals.Thus, we see in this cohort more often lymphomas not related to the low CD4+ cell level, i.e., Burkitt lymphoma.We suppose that a study in a larger cohort will help to discover the pathogenetic features of lymphomas in patients with HIV thus clarifying the role of CCR5 gene mutation status.

Autologous anti-CD19 CAR-T cells can be produced by means of closed automated systems, which seems to be the most convenient platform for the point-of-care production.However, to fully comply with good practices and to utilize relatively low-grade of clean air environments, the production processes should be carried out in a completely closed format, without usage of pooled human blood products.The purpose of the present study was to test a production process that fully meets the necessary requirements.

While DNA and messenger RNA (mRNA) based therapies are currently changing the biomedical field, the delivery of genetic materials remains the key problem preventing the wide introduction of these methods into clinical practice. Therefore, the creation of new methods for intracellular gene delivery, particularly to hard-to-transfect, clinically relevant cell populations is a pressing issue. Here, we report on the design of a novel approach to format 50-150 nm calcium carbonate particles in the vaterite state and using them as a template for polymeric core-shell nanoparticles. We apply such core-shell nanoparticles as safe and efficient carriers for mRNA and pDNA. We prove that such nanocarriers are actively internalized by up to 99% of primary T-lymphocytes and exert minimal toxicity with the viability of >90%. We demonstrate that these nanocarriers mediate more efficient transfection compared with the standard electroporation method (90% vs. 51% for mRNA and 62% vs. 39% for plasmid DNA) in primary human T-lymphocytes as a model of the hard to transfect type that is widely used in gene and cell therapy approaches. Importantly, these polymeric nanocarriers can be used in serum containing basic culture medium without special conditions and equipment, thus having potential for being introduced in clinical development. As a result, we have provided proof-of-principle that our nanosized containers represent a promising universal non-viral platform for efficient and safe gene delivery.

The predictive value of graft composition and plasma biomarkers on the outcome of allogeneic HSCT is well known for conventional GVHD prophylaxis based on calcineurin inhibitors with or without antithymocyte globulin. Currently, there is limited data whether these results could be translated to post transplantation cyclophosphamide (PTCy). The prospective extension cohort of NCT02294552 trial enrolled 79 adult patients with acute leukemia in CR. Twenty-six received matched-related bone marrow (BM) grafts with single-agent PTCy and 53 received unrelated peripheral blood stem cell graft (PBSC) with PTCy, tacrolimus, and MMF. The grafts were studied by the flow cytometry, and plasma samples were analyzed by ELISA. In the cluster and major component analysis, we determined that transplantation from donors with high content of CD3, NKT, and CD16-CD56 + subpopulations in the PBSC grafts was associated with poor immunological recovery and compromised event-free survival (50% vs. 80%, HR 2.93, p = 0.015) both due to increased relapse incidence and non-relapse mortality. The significant independent predictor of moderate and severe chronic GVHD was the high prevalence of and iNKT, Vβ11, and double-positive cells in the PBSC grafts from young donors (HR 2.75, p = 0.0483). No patterns could be identified for BM grafts and for plasma biomarkers.

An important area in modern malignant tumor therapy is the optimization of antitumor drugs pharmacokinetics. The use of some antitumor drugs is limited in clinical practice due to their high toxicity. Therefore, the strategy for optimizing the drug pharmacokinetics focuses on the generation of high local concentrations of these drugs in the tumor area with minimal systemic and tissue-specific toxicity. This can be achieved by encapsulation of highly toxic antitumor drug (vincristine (VCR) that is 20-50 times more toxic than widely used the antitumor drug doxorubicin) into nano- and microcarriers with their further association into therapeutically relevant cells that possess the ability to migrate to sites of tumor. Here, we fundamentally examine the effect of drug carrier size on the behavior of human mesenchymal stem cells (hMSCs), including internalization efficiency, cytotoxicity, cell movement, to optimize the conditions for the development of carrier-hMSCs drug delivery platform. Using the malignant tumors derived from patients, we evaluated the capability of hMSCs associated with VCR-loaded carriers to target tumors using a three-dimensional spheroid model in collagen gel. Compared to free VCR, the developed hMSC-based drug delivery platform showed enhanced antitumor activity regarding those tumors that express CXCL12 (stromal cell-derived factor-1 (SDF-1)) gene, inducing directed migration of hMSCs via CXCL12 (SDF-1)/CXCR4 pathway. These results show that the combination of encapsulated antitumor drugs and hMSCs, which possess the properties of active migration into tumors, is therapeutically beneficial and demonstrated high efficiency and low systematic toxicity, revealing novel strategies for chemotherapy in the future.

CRISPR-Cas9 is a revolutionary genome-editing technology that has enormous potential for the treatment of genetic diseases. However, the lack of efficient and safe, non-viral delivery systems has hindered its clinical application. Here, we report on the application of polymeric and hybrid microcarriers, made of degradable polymers such as polypeptides and polysaccharides and modified by silica shell, for delivery of all CRISPR-Cas9 components. We found that these microcarriers mediate more efficient transfection than a commercially available liposome-based transfection reagent (>70% vs. <50% for mRNA, >40% vs. 20% for plasmid DNA). For proof-of-concept, we delivered CRISPR-Cas9 components using our capsules to dTomato-expressing HEK293T cells-a model, in which loss of red fluorescence indicates successful gene editing. Notably, transfection of indicator cells translated in high-level dTomato knockout in approx. 70% of transfected cells. In conclusion, we have provided proof-of-principle that our micro-sized containers represent promising non-viral platforms for efficient and safe gene editing.

The paper analyzes peripheral blood findings from 34 patients (276 tests) at different time points following high-dose polychemotherapy and autologous hemopoietic stem cell transplantation. Most patients had resistant disease. Blood samples were tested for 26 parameters including reticulocytes, reticulocyte and platelet indices. Ferritin, soluble transferring receptor contents, endogenous erythropoietin were measured. Most patients had anemia before high-dose chemotherapy identified as chronic anemia with high or normal ferritin levels and erythropoietin production not adequate to anemia degree. Testing for young platelet, reticulocyte forms and their indices was shown highly informative for prediction of hemopoiesis recovery start.

Based on the annual UNAIDS reports the number of HIVinfected patients is continually growing since 1983. Antiretroviral Therapy (ART) allows to prolong life expectancy, but the problem of life quality and overall survival is still remaining. Nowadays, in the era of ART, one of the main cause of mortality in HIV-infected patients is malignancies. Lymphomas play one of the key roles in this group of diseases. The treatment of lymphomas includes combined regiments of chemotherapy with a curative potential. High dose chemotherapy with autologous hematopoietic stem cell transplant (auto-HSCT) is the main path of the treatment for relapsed / refractory lymphomas. In the last few years with a development of the genome editing technology auto-HSCT is becoming one of the most promising methods of HIV treatment. The case of “Berlin patient” when allogeneic HSCT from donor with mutation CCR5-delta32 lead to cure from HIV and proof of concept the efficacy of the gene therapy for HIV based on HSCT. Hematopoietic stem cell transplantation with edited autologous HSC (CCR5 knockout by site-specific genome editing tools with engineering nucleases) is a comprehensive treatment for this cohort of patients. On one hand, high dose chemotherapy with auto-HSCT cures the malignancy; on the other hand auto-HSCT works as a delivery method for the edited cells and creates an environment for the HIV eradication. This review is dedicated to HIV and oncology, methods of treatment of hematological malignancies and HIV-infection using genome editing technology based on HSCT.

Genome editing is a breakthrough technology which consists of the process of precise modifications introduction into the genome of any organism.This scientific breakthrough provides a powerful tool for the errors correction in the nucleotide sequence of DNA.The development of the genome editing has inverted the concept of an available target for the therapeutic correction.The opportunity of highly precise and safe entering of single-and double-stranded breaks into the human DNA followed by natural DNA repair mechanisms has changed current approaches of the gene therapy and opened up new horizons in the treatment of numerous diseases.Genome editing is being developed to treat not only monogenic diseases but also infectious diseases and cancer.In the current review, we discuss the therapeutic application of genome editing.

Mesenchymal stem cells (MSCs) are widely used in cell therapy due to their convenience, multiline differentiation potential, reproducible protocols, and biological properties. The potential of MSCs to impregnate magnetic microcapsules and their possible influence on cell function and ability to response to magnetic field have been explored. Interestingly, the cells suspended in media show much higher ability in internalization of microcapsules, then MSCs adhere into the surface. There is no significant effect of microcapsules on cell toxicity compared with other cell line-capsule internalization reported in literature. Due to internalization of magnetic capsules by the cells, such cell engineering platform is responsive to external magnetic field, which allows to manipulate MSC migration. Magnetically sorted MSCs are capable to differentiation as confirmed by their conversion to adipogenic and osteogenic cells using standard protocols. There is a minor effect of capsule internalization on cell adhesion, though MSCs are still able to form spheroid made by dozen of thousand MSCs. This work demonstrates the potential of use of microcapsule impregnated MSCs to carry internalized micron-sized vesicles and being navigated with external magnetic signaling.