Allogeneic adoptive cell transfer therapy as a potent universal treatment for cancer

Helper innate lymphoid cells as cell therapy for cancer

Although the first cancer immunotherapy was given in the clinic more than a century ago, this line of treatment has remained more of a distant goal than a practical therapy due to limited understanding of the tumour microenvironment and the mechanisms at play within it, which led to failures of numerous clinical trials. However, in the last two decades, the immune checkpoint inhibitors (ICIs) and chimeric antigen receptor-T cell therapies have revolutionized the treatment of cancer and provided proof-of-concept that immunotherapies are a viable option. So far, immunotherapies have majoritarily focused on utilizing T cells; however, T cells are not autonomous but rather function as part of, and therefore are influenced by, a vast cast of other immune cells, including innate lymphoid cells (ILCs). Here, we summarize the role of ILCs, especially helper ILCs, in tumour development, progression and metastasis, as well as their potential to be used as immunotherapy for cancer. By reviewing the studies that used helper ILCs as adoptive cell therapy (ACT), we highlight the rationale behind considering these cells as novel ACT for cancer as well as identify open questions and areas for future research.

Advances of Tumorigenesis, Diagnosis at Early Stage, and Cellular Immunotherapy in Gastrointestinal Malignancies

Globally, in 2018, 4.8 million new patients have a diagnosis of gastrointestinal (GI) cancers, while 3.4 million people died of such disorders. GI malignancies are tightly relevant to 26% of the world-wide cancer incidence and occupies 35% of all cancer-associated deaths. In this article, we principally investigated molecular and cellular mechanisms of tumorigenesis in five major GI cancers occurring at esophagus, stomach, liver, pancreas, and colorectal region that illustrate high morbidity in Eastern and Western countries. Moreover, through this investigation, we not only emphasize importance of the tumor microenvironment in development and treatment of malignant tumors but also identify significance of M2PK, miRNAs, ctDNAs, circRNAs, and CTCs in early detection of GI cancers, as well as systematically evaluate contribution of personalized precision medicine including cellular immunotherapy, new antigen and vaccine therapy, and oncolytic virotherapy in treatment of GI cancers.

Current strategies to improve the safety of chimeric antigen receptor (CAR) modified T cells

Adoptive immunotherapy adopting chimeric antigen receptor (CAR) modified T cells has arisen attention as a hard-hitting therapy for numerous cancers. CARs are genetically engineered receptors that could stimulate tumor cytotoxicity once binding to the specific tumor epitopes. In spite of current noteworthy achievements in hematologic malignancies, the safety problems have aroused public awareness. In this review, we will focus on recent potential strategies to improve the security of CAR modified T cells.

Characterization and functional analysis of a slow-cycling subpopulation in colorectal cancer enriched by cell cycle inducer combined chemotherapy

The concept of cancer stem cells has been proposed in various malignancies including colorectal cancer. Recent studies show direct evidence for quiescence slow-cycling cells playing a role in cancer stem cells. There exists an urgent need to isolate and better characterize these slow-cycling cells. In this study, we developed a new model to enrich slow-cycling tumor cells using cell-cycle inducer combined with cell cycle-dependent chemotherapy in vitro and in vivo. Our results show that Short-term exposure of colorectal cancer cells to chemotherapy combined with cell-cycle inducer enriches for a cell-cycle quiescent tumor cell population. Specifically, these slow-cycling tumor cells exhibit increased chemotherapy resistance in vitro and tumorigenicity in vivo. Notably, these cells are stem-cell like and participate in metastatic dormancy. Further exploration indicates that slow-cycling colorectal cancer cells in our model are less sensitive to cytokine-induced-killer cell mediated cytotoxic killing in vivo and in vitro. Collectively, our cell cycle inducer combined chemotherapy exposure model enriches for a slow-cycling, dormant, chemo-resistant tumor cell sub-population that are resistant to cytokine induced killer cell based immunotherapy. Studying unique signaling pathways in dormant tumor cells enriched by cell cycle inducer combined chemotherapy treatment is expected to identify novel therapeutic targets for preventing tumor recurrence.

The PD-1/B7-H1 pathway modulates the natural killer cells versus mouse glioma stem cells

PURPOSE

Glioblastoma multiforme (GBM) is the most malignant primary type of brain tumor in adults. There has been increased focus on the immunotherapies to treat GBM patients, the therapeutic value of natural killer (NK) cells is still unknown. Programmed death-1 (PD-1) is a major immunological checkpoint that can negatively regulate the T-cell-mediated immune response. We tested the combination of the inhibiting the PD-1/B7H1 pathway with a NK-cell mediated immune response in an orthotopic mouse model of GBM.

METHODS AND MATERIALS

Mouse glioma stem cells (GL261GSCs) and mouse NK cells were isolated and identified. A lactate dehydrogenase (LDH) assay was perfomed to detect the cytotoxicity of NK cells against GL261GSCs. GL261GSCs were intracranially implanted into mice, and the mice were stratified into 3 treatment groups: 1) control, 2) NK cells treatment, and 3) PD-1 inhibited NK cells treatment group. Overall survival was quantified, and animal magnetic resonance imaging (MRI) was performed to determine tumor growth. The brains were harvested after the mice were euthanized, and immunohistochemistry against CD45 and PCNA was performed.

RESULTS

The mouse NK cells were identified as 90% CD3- NK1.1+CD335+ by flow cytometric analysis. In the LDH assay, the ratios of the damaged GL261GSCs, with the E:T ratios of 2.5:1, 5:1, and 10:1, were as follows: 1) non-inhibited group: 7.42%, 11.31%, and 15.1%, 2) B7H1 inhibited group: 14.75%, 18.25% and 29.1%, 3) PD-1 inhibited group: 15.53%, 19.21% and 29.93%, 4) double inhibited group: 33.24%, 42.86% and 54.91%. In the in vivo experiments, the mice in the PD-1 inhibited NK cells treatment group and IL-2-stimulated-NK cells treatment group displayed a slowest tumor growth (F = 308.5, P<0.01) and a slower tumor growth compared with control group (F = 118.9, P<0.01), respectively. The median survival of the mice in the three groups were as follows: 1) conrol group: 29 days, 2) NK cells treatment group: 35 days (P = 0.0012), 3) PD-1 inhibited NK cells treatment group: 44 days (P = 0.0024). Immunologic data of PCNA-positive cell ratios and CD45-positive cell ratios of the tumor specimens in the three groups were as follows: 1) control group: 65.72% (PCNA) and 0.92% (CD45), 2) NK treatment group: 27.66% (PCNA) and 13.46% (CD45), and 3) PD-1 inhibited NK cells treatment group: 13.66% (PCNA) and 23.66% (CD45) (P<0.001).

CONCLUSION

The results demonstrated that blockade of PD-1/B7H1 pathway could promote mouse NK cells to kill the GL261GSCs, and the PD-1-inhibited NK cells could be a feasible immune therapeutic approach against GBM.

Targeting glioblastoma with NK cells and mAb against NG2/CSPG4 prolongs animal survival

Glioblastoma (GBM) is the most malignant brain tumor where patients' survival is only 14.6 months, despite multimodal therapy with debulking surgery, concurrent chemotherapy and radiotherapy. There is an urgent, unmet need for novel, effective therapeutic strategies for this devastating disease. Although several immunotherapies are under development for the treatment of GBM patients, the use of natural killer (NK) cells is still marginal despite this being a promising approach to treat cancer. In regard of our knowledge on the role of NG2/CSPG4 in promoting GBM aggressiveness we investigated the potential of an innovative immunotherapeutic strategy combining mAb9.2.27 against NG2/CSPG4 and NK cells in preclinical animal models of GBM. Multiple immune escape mechanisms maintain the tumor microenvironment in an anti-inflammatory state to promote tumor growth, however, the distinct roles of resident microglia versus recruited macrophages is not elucidated. We hypothesized that exploiting the cytokine release capabilities of activated (NK) cells to reverse the anti-inflammatory axis combined with mAb9.2.27 targeting the NG2/CSPG4 may favor tumor destruction by editing pro-GBM immune responses. Combination treatment with NK+mAb9.2.27 diminished tumor growth that was associated with reduced tumor proliferation, increased cellular apoptosis and prolonged survival compared to vehicle and monotherapy controls. The therapeutic efficacy was mediated by recruitment of CCR2low macrophages into the tumor microenvironment, increased ED1 and MHC class II expression on microglia that might render them competent for GBM antigen presentation, as well as elevated IFN-γ and TNF-α levels in the cerebrospinal fluid compared to controls. Depletion of systemic macrophages by liposome-encapsulated clodronate decreased the CCR2low macrophages recruited to the brain and abolished the beneficial outcomes. Moreover, mAb9.2.27 reversed tumor-promoting effects of patient-derived tumor-associated macrophage/microglia(TAM) ex vivo.Taken together, these findings indicate thatNK+mAb9.2.27 treatment may be an amenable therapeutic strategy to treat NG2/CSPG4 expressing GBMs. We provide a novel conceptual approach of combination immunotherapy for glioblastoma. The results traverse beyond the elucidation of NG2/CSPG4 as a therapeutic target, but demonstrate a proof of concept that this antibody may hold potential for the treatment of GBM by activation of tumor infiltrated microglia/macrophages.

Improving the efficacy and safety of engineered T cell therapy for cancer

Adoptive T-cell therapy (ACT) using tumor-infiltrating lymphocytes (TILs) is a powerful immunotherapeutics approach against metastatic melanoma. The success of TIL therapy has led to novel strategies for redirecting normal T cells to recognize tumor-associated antigens (TAAs) by genetically engineering tumor antigen-specific T cell receptors (TCRs) or chimeric antigen receptor (CAR) genes. In this manner, large numbers of antigen-specific T cells can be rapidly generated compared with the longer term expansion of TILs. Great efforts have been made to improve these approaches. Initial clinical studies have demonstrated that genetically engineered T cells can mediate tumor regression in vivo. In this review, we discuss the development of TCR and CAR gene-engineered T cells and the safety concerns surrounding the use of these T cells in patients. We highlight the importance of judicious selection of TAAs for modified T cell therapy and propose solutions for potential "on-target, off-organ" toxicity.