Immunological-based approaches for cancer therapy

The immunologic landscape of tumors has been continuously unveiled, providing a new look at the interactions between cancer cells and the immune system. Emerging tumor cells are constantly eliminated by the immune system, but some cells establish a long-term equilibrium phase leading to tumor immunoediting and, eventually, evasion. During this process, tumor cells tend to acquire more mutations. Bearing a high mutation burden leads to a greater number of neoantigens with the potential to initiate an immune response. Although many tumors evoke an immune response, tumor clearance by the immune system does not occur due to a suppressive tumor microenvironment. The mechanisms by which tumors achieve the ability to evade immunologic control vary. Understanding these differences is crucial for the improvement and application of new immune-based therapies. Much effort has been placed in developing in silico algorithms to predict tumor immunogenicity and to characterize the microenvironment via high-throughput sequencing and gene expression techniques. Each sequencing source, transcriptomics, and genomics yields a distinct level of data, helping to elucidate the tumor-based immune responses and guiding the fine-tuning of current and upcoming immune-based therapies. In this review, we explore some of the immunological concepts behind the new immunotherapies and the bioinformatic tools to study the immunological aspects of tumors, focusing on neoantigen determination and microenvironment deconvolution. We further discuss the immune-based therapies already in clinical use, those underway for future clinical application, the next steps in immunotherapy, and how the characterization of the tumor immune contexture can impact therapies aiming to promote or unleash immune-based tumor elimination

Immunological-based approaches for cancer therapy

The immunologic landscape of tumors has been continuously unveiled, providing a new look at the interactions between cancer cells and the immune system. Emerging tumor cells are constantly eliminated by the immune system, but some cells establish a long-term equilibrium phase leading to tumor immunoediting and, eventually, evasion. During this process, tumor cells tend to acquire more mutations. Bearing a high mutation burden leads to a greater number of neoantigens with the potential to initiate an immune response. Although many tumors evoke an immune response, tumor clearance by the immune system does not occur due to a suppressive tumor microenvironment. The mechanisms by which tumors achieve the ability to evade immunologic control vary. Understanding these differences is crucial for the improvement and application of new immune-based therapies. Much effort has been placed in developing in silico algorithms to predict tumor immunogenicity and to characterize the microenvironment via high-throughput sequencing and gene expression techniques. Each sequencing source, transcriptomics, and genomics yields a distinct level of data, helping to elucidate the tumor-based immune responses and guiding the fine-tuning of current and upcoming immune-based therapies. In this review, we explore some of the immunological concepts behind the new immunotherapies and the bioinformatic tools to study the immunological aspects of tumors, focusing on neoantigen determination and microenvironment deconvolution. We further discuss the immune-based therapies already in clinical use, those underway for future clinical application, the next steps in immunotherapy, and how the characterization of the tumor immune contexture can impact therapies aiming to promote or unleash immune-based tumor elimination

An Efficient Low Cost Method for Gene Transfer to T Lymphocytes

<div><p></p><p>Gene transfer to T lymphocytes has historically relied on retro and lentivirus, but recently transposon-based gene transfer is rising as a simpler and straight forward approach to achieve stable transgene expression. Transfer of expression cassettes to T lymphocytes remains challenging, being based mainly on commercial kits.</p> <p>Aims</p><p>We herein report a convenient and affordable method based on <i>in house</i> made buffers, generic cuvettes and utilization of the widely available Lonza nucleofector II device to promote efficient gene transfer to T lymphocytes.</p> <p>Results</p><p>This approach renders high transgene expression levels in primary human T lymphocytes (mean 45%, 41–59%), the hard to transfect murine T cells (mean 38%, 36–42% for C57/BL6 strain) and human Jurkat T cell line. Cell viability levels after electroporation allowed further manipulations such as <i>in vitro</i> expansion and Chimeric Antigen Receptor (CAR) mediated gain of function for target cell lysis.</p> <p>Conclusions</p><p>We describe here an efficient general protocol for electroporation based modification of T lymphocytes. By opening access to this protocol, we expect that efficient gene transfer to T lymphocytes, for transient or stable expression, may be achieved by an increased number of laboratories at lower and affordable costs.</p> </div

Electroporation of the Jurkat T cell line.

<p>(<b>A</b>) Jurkat cells were electroporated with pT2-GFP in the presence of each of the 7 different buffers. Viability and GFP expression were evaluated by flow cytometry after 24 h. Cell viability is expressed as % of the control mock electroporated condition (100%). Electroporation scores were determined as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0060298#s2" target="_blank">materials and methods</a>. Statistical analysis was performed using One Way ANOVA and Tukey post test (* = P<0.05). (<b>B</b>) Jurkat cells were electroporated with buffer 3P. Cell viability and GFP expression were observed until day 20. Values in this figure are the average of two separate experiments in triplicate and are expressed as mean±SEM. Data were analyzed by unpaired Student t test; p<0.05 (*);p<0.01 (**).</p

Electroporation of transposon and transposase maintains transgene expression after cell viability recovery.

<p>PBMCs from two healthy donors were electroporated using 1SM buffer, 20 µg of pT2-GFP plasmid and 2 µg of SB100x transposase. Cell viability and GFP expression were analyzed by flow cytometry on day 1 and 9. Values are the average of two donors in triplicate and are expressed as mean±SEM.</p

Electroporation of resting vs activated mouse primary T lymphocytes.

<p>Total lymphocytes from lymph nodes of C57BL/6 mice were isolated and either directly electroporated or activated for 24 h with anti-CD3/anti-CD28 and then electroporated. Buffer 2S and 4 µg of pT2-GFP plasmid were used. Cell viability and GFP expression were analyzed after 24 h by flow cytometry. Cell viability is normalized to control (not electroporated) cells. Data are representative of two experiments in triplicate and expressed as mean±SEM. Data were analyzed by unpaired Student t test; p<0.0001 (**) or p = 0.002 (*).</p

Stem Cells and Development

Texto completo: acesso restrito. p. 1711-1720Flavonoids have key functions in the regulation of multiple cellular processes; however, their effects have been poorly examined in pluripotent stem cells. Here, we tested the hypothesis that neurogenesis induced by all-trans retinoic acid (RA) is enhanced by agathisflavone (FAB, Caesalpinia pyramidalis Tull). Mouse embryonic stem (mES) cells and induced pluripotent stem (miPS) cells growing as embryoid bodies (EBs) for 4 days were treated with FAB (60 μM) and/or RA (2 μM) for additional 4 days. FAB did not interfere with the EB mitotic rate of mES cells, as evidenced by similar percentages of mitotic figures labeled by phospho-histone H3 in control (3.4%±0.4%) and FAB-treated groups (3.5%±1.1%). Nevertheless, the biflavonoid reduced cell death in both control and RA-treated EBs from mES cells by almost 2-fold compared with untreated EBs. FAB was unable, by itself, to induce neuronal differentiation in EBs after 4 days of treatment. On the other hand, FAB enhanced neuronal differentiation induced by RA in both EBs of mES and miPS. FAB increased the percentage of nestin-labeled cells by 2.7-fold (mES) and 2.4 (miPS) and β-tubulin III–positive cells by 2-fold (mES) and 2.7 (miPS) in comparison to RA-treated EBs only. FAB increased the expression of RA receptors α and β in mES EBs, suggesting that the availability of RA receptors is limiting RA-induced neurogenesis in pluripotent stem cells. This is the first report to describe that naturally occurring biflavonoids regulate apoptosis and neuronal differentiation in pluripotent stem cells

T cell electroporation with Chimeric Antigen Receptor (CAR) results in stable gene expression conferring target-specific cytotoxicity.

<p>PBMCs from one donor were electroporated using 1SM buffer, 20 µg of pT3-20z plasmid and 0,5 µg of SB100x transposase plasmid. One day later, lymphocytes were stimulated with irradiated L388 cells and CAR expression was evaluated until d+30 by flow cytometry analysis using an anti-fab antibody. (A) Representative histograms of 20z CAR expression at d+1, d+10, d+20 and d+30 after electroporation (gray line = non electroporated cells stained anti-Fab; black line = lymphocytes electroporated with pT3-20z). (B) Analysis of 20z CAR expression until d+30 summarizing data of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0060298#pone-0060298-g008" target="_blank">Figure 8A</a>. (C) Kinetics of expansion of control mock electroporated (Neg) or 20z+ lymphocytes after stimulation with L388 cells. (D) Expanded cells were used in different effector/target (E/T) ratios in a cytotoxic assay against the CD19+/CD20+ Nalm-6 GFP+target cell line; Neg = CTLs not electroporated.</p

Long term expression of GFP after electroporation with buffer 1SM.

<p>PBMCs from two healthy donors were electroporated using 1SM buffer and 4 µg of pT2-GFP plasmid. After 24 h cells were activated with anti-CD3/anti-CD28 and GFP expression was evaluated for 7 days by flow cytometry.</p

Overhauling CAR T Cells to Improve Efficacy, Safety and Cost

Gene therapy is now surpassing 30 years of clinical experience and in that time a variety of approaches has been applied for the treatment of a wide range of pathologies. While the promise of gene therapy was over-stated in the 1990&rsquo;s, the following decades were met with polar extremes between demonstrable success and devastating setbacks. Currently, the field of gene therapy is enjoying the rewards of overcoming the hurdles that come with turning new ideas into safe and reliable treatments, including for cancer. Among these modalities, the modification of T cells with chimeric antigen receptors (CAR-T cells) has met with clear success and holds great promise for the future treatment of cancer. We detail a series of considerations for the improvement of the CAR-T cell approach, including the design of the CAR, routes of gene transfer, introduction of CARs in natural killer and other cell types, combining the CAR approach with checkpoint blockade or oncolytic viruses, improving pre-clinical models as well as means for reducing cost and, thus, making this technology more widely available. While CAR-T cells serve as a prime example of translating novel ideas into effective treatments, certainly the lessons learned will serve to accelerate the current and future development of gene therapy drugs