Antigen-independent killer cells prepared for adoptive immunotherapy: One source, divergent protocols, diverse nomenclature

The paths and challenges of "off-the-shelf" CAR-T cell therapy: An overview of clinical trials

The advent of chimeric antigen receptor T cells (CAR-T cells) has made a tremendous revolution in the era of cancer immunotherapy, so that since 2017 eight CAR-T cell products have been granted marketing authorization. All of these approved products are generated from autologous sources, but this strategy faces several challenges such as time-consuming and expensive manufacturing process and reduced anti-tumor potency of patients' T cells due to the disease or previous therapies. The use of an allogeneic source can overcome these issues and provide an industrial, scalable, and standardized manufacturing process that reduces costs and provides faster treatment for patients. Nevertheless, for using allogeneic CAR-T cells, we are faced with the challenge of overcoming two formidable impediments: severe life-threatening graft-versus-host-disease (GvHD) caused by allogeneic CAR-T cells, and allorejection of allogeneic CAR-T cells by host immune cells which is called "host versus graft" (HvG). In this study, we reviewed recent registered clinical trials of allogeneic CAR-T cell therapy to analyze different approaches to achieve a safe and efficacious "off-the-shelf" source for chimeric antigen receptor (CAR) based immunotherapy.

An Overview: Genetic Tumor Markers for Early Detection and Current Gene Therapy Strategies

Genomic instability is considered a fundamental factor involved in any neoplastic disease. Consequently, the genetically unstable cells contribute to intratumoral genetic heterogeneity and phenotypic diversity of cancer. These genetic alterations can be detected by several diagnostic techniques of molecular biology and the detection of alteration in genomic integrity may serve as reliable genetic molecular markers for the early detection of cancer or cancer-related abnormal changes in the body cells. These genetic molecular markers can detect cancer earlier than any other method of cancer diagnosis, once a tumor is diagnosed, then replacement or therapeutic manipulation of these cancer-related abnormal genetic changes can be possible, which leads toward effective and target-specific cancer treatment and in many cases, personalized treatment of cancer could be performed without the adverse effects of chemotherapy and radiotherapy. In this review, we describe how these genetic molecular markers can be detected and the possible ways for the application of this gene diagnosis for gene therapy that can attack cancerous cells, directly or indirectly, which lead to overall improved management and quality of life for a cancer patient.

Efficacy of adoptively transferred allogeneic CIK cells on colorectal cancer: Augmentative antitumoral effects of GvHD

OBJECTIVE

A preclinical study was designed to evaluate the effects of adoptively transferred cytokine-induced killer (CIK) cells on colorectal adenocarcinoma.

METHODS

Forty NOG mice bearing HT-29 xenograft tumors were developed and equally divided into 2 groups of treatment and control. The mice in the treatment group received cumulatively 40-60 × 10⁶ CIK cells in four divided doses.

RESULTS

Median tumor doubling times for HT-29 xenograft tumors in the treatment and control groups were found to be 8.98 and 4.32 days; respectively. The treatment resulted in tumor growth delay (TGD) of 52.5 %. CIK cell-induced log cell kill (LCK) was found to be 0.67, which implies reduction of 78.6 % of neoplastic colorectal cells. Median length of survival in the treated mice was significantly longer than controls (57 (41-63) vs 41 (31-57) days, P < 0.001). Mice in the treatment group experienced graft-versus-host disease (GvHD) from median of day 13th after the cell therapy. LCK and TGD significantly increased after emergence of GvHD. After necropsy, tumors of the treatment group contained high levels of human-originated CD3⁺, CD4⁺ and CD8⁺ cells and showed significantly lower mitotic counts (P < 0.001) and residual tumor scores (P = 0.005) than the controls (entirely negative for the mentioned CD markers). Ninety percent of the treated mice were found to be responding.

CONCLUSIONS

Adoptive transfer of allogeneic CIK cells may be an efficient antitumoral therapy for colorectal cancer. Allogeneic CIK cell-mediated GvHD may contribute to amplification of graft-versus-tumor effects of the cellular therapy.

Optimization of Culture Media for Ex vivo T-Cell Expansion for Adoptive T-Cell Therapy

BACKGROUND

Adoptive T-cell therapy is a promising treatment strategy for cancer immunotherapy. The ability of immunotherapy based on the adoptive cell transfer of genetically modified T cells to generate powerful clinical responses has been highlighted by recent clinical success. Techniques which are used to expand large numbers of T cells from different sources are critical in adoptive cell therapy. In this study, we evaluated the expansion, proliferation, activation of T lymphocytes, in the presence of various concentrations of interleukin-2, phytohemagglutinin (PHA), and insulin.

MATERIALS AND METHODS

The effect of different supplemented culture media on T cell expansion was evaluated using MTT assay. The expression level of the Ki-67 proliferation marker was evaluated by real-time polymerase chain reaction. In addition, flow cytometry analysis was performed to access T cell subpopulations.

RESULTS

Our results showed that supplemented culture media with an optimized concentration of PHA and interleukin-2 increased total fold expansion of T cells up to 500-fold with approximately 90% cell viability over 7 days. The quantitative assessment of Ki-67 in expanded T cells showed a significant elevation of this proliferation marker. Flow cytometry was also used to assess the proportion of CD4+ and CD8+ cells, and the main expanded population was CD3+ CD8+ cells.

CONCLUSIONS

Based on these findings, we introduced a low-cost and rapid method to support the efficient expansion of T cells for adoptive cell therapy and other in vivo experiments.

Adoptive NK-cell transfer as a potential treatment paradigm for Wilms tumor: A preclinical study

BACKGROUND

Natural killer (NK) cell therapy has been shown to be effective in the treatment of some cancers. However, the effects of this adoptive immunotherapy have not been investigated for Wilms tumor (WT). In this study, the effects of adoptive NK-cell transfer on a patient-derived xenograft (PDX) model of anaplastic WT were evaluated, and the impacts of cell source and ex vivo activation strategy on the therapeutic efficacy of NK-cell product were appraised.

METHODS

NK cells were isolated from human peripheral blood mononuclear cells (NK_PB ) and human cord blood (NK_CB ), and were expanded and activated using a cytokine cocktail. Another group of NK cells (NK_ET ) was produced through activation with the exosomes extracted from previously challenged NK_PB cells with WT. PDX-bearing mice were treated with clinically relevant doses of NK_PB , NK_CB , NK_ET , standard chemotherapy, and placebo (phosphate-buffered saline).

RESULTS

PDX models treated with NK_CB showed a better survival rate, though the difference among the study groups was not significant. Compared with the placebo control group, NK_CB significantly improved the histopathologic response, NK_PB significantly inhibited the proliferation of neoplastic cells, and NK_ET led to a significant decrease in the metastasis score (all p-values <.05). Standard chemotherapy provided the greatest tumor growth inhibition and the lowest mitotic count, though it did not show any significant advantage over NK-cell therapies in any of the outcome parameters in two-by-two comparisons.

CONCLUSIONS

This study spotlights the efficacy of adoptive NK-cell transfer as a potential treatment candidate for high-risk WT.

Cellular immunotherapies for cancer

Cancer is a major burden on the healthcare system, and new therapies are needed. Recently, the development of immunotherapies, which aim to boost or use the immune system, or its constituents, as a tool to fight malignant cells, has provided a major new tool in the arsenal of clinicians and has revolutionized the treatment of many cancers.

Cellular immunotherapies are based on the administration of living cells to patients and have developed hugely, especially since 2010 when Sipuleucel-T (Provenge), a DC vaccine, was the first cellular immunotherapy to be approved by the FDA. The ensuing years have seen two further cellular immunotherapies gain FDA approval: tisagenlecleucel (Kymriah) and axicabtagene ciloleucel (Yescarta).

This review will give an overview of the principles of immunotherapies before focusing on the major forms of cellular immunotherapies individually, T cell-based, natural killer (NK) cell-based and dendritic cell (DC)-based, as well as detailing some of the clinical trials relevant to each therapy.