Treatment of a solid tumor using engineered drug-resistant immunocompetent cells and cytotoxic chemotherapy

Oncolytic virotherapy augments self-maintaining natural killer cell line cytotoxicity against neuroblastoma

BACKGROUND

Neuroblastoma is the most common extracranial solid tumor in children and accounts for 15% of pediatric cancer related deaths. Targeting neuroblastoma with immunotherapies has proven challenging due to a paucity of immune cells in the tumor microenvironment and the release of immunosuppressive cytokines by neuroblastoma tumor cells. We hypothesized that combining an oncolytic Herpes Simplex Virus (oHSV) with natural killer (NK) cells might overcome these barriers and incite tumor cell death.

METHODS

We utilized MYCN amplified and non-amplified neuroblastoma cell lines, the IL-12 expressing oHSV, M002, and the human NK cell line, NK-92 MI. We assessed the cytotoxicity of NK cells against neuroblastoma with and without M002 infection, the effects of M002 on NK cell priming, and the impact of M002 and priming on the migratory capacity and CD107a expression of NK cells. To test clinical applicability, we then investigated the effects of M002 and NK cells on neuroblastoma in vivo.

RESULTS

NK cells were more attracted to neuroblastoma cells that were infected with M002. There was an increase in neuroblastoma cell death with the combination treatment of M002 and NK cells both in vitro and in vivo. Priming the NK cells enhanced their cytotoxicity, migratory capacity and CD107a expression.

CONCLUSIONS

To the best of our knowledge, these investigations are the first to demonstrate the effects of an oncolytic virus combined with self-maintaining NK cells in neuroblastoma and the priming effect of neuroblastoma on NK cells. The current studies provide a deeper understanding of the relation between NK cells and neuroblastoma and these data suggest that oHSV increases NK cell cytotoxicity towards neuroblastoma.

A combined treatment regimen of MGMT-modified γδ T cells and temozolomide chemotherapy is effective against primary high grade gliomas

Chemotherapeutic drugs such as the alkylating agent Temozolomide (TMZ), in addition to reducing tumor mass, can also sensitize tumors to immune recognition by transient upregulation of multiple stress induced NKG2D ligands (NKG2DL). However, the potential for an effective response by innate lymphocyte effectors such as NK and γδ T cells that recognize NKG2DL is limited by the drug's concomitant lymphodepleting effects. We have previously shown that modification of γδ T cells with a methylguanine DNA methyltransferase (MGMT) transgene confers TMZ resistance via production of O6-alkylguanine DNA alkyltransferase (AGT) thereby enabling γδ T cell function in therapeutic concentrations of TMZ. In this study, we tested this strategy which we have termed Drug Resistant Immunotherapy (DRI) to examine whether combination therapy of TMZ and MGMT-modified γδ T cells could improve survival outcomes in four human/mouse xenograft models of primary and refractory GBM. Our results confirm that DRI leverages the innate response of γδ T cells to chemotherapy-induced stress associated antigen expression and achieves synergies that are significantly greater than either individual approach.

Evaluation of a Low-Toxicity PARP Inhibitor as a Neuroprotective Agent for Parkinson's Disease

Repurposing PARP-1 inhibitors (PARPi) for non-oncological applications offers an attractive therapeutic strategy for pathological conditions characterized by PARP-1 hyperactivity. In the context of Parkinson's disease (PD), PARP-1 hyperactivity has been linked to neuronal death and disease progression. From a therapy perspective, the evaluation of PARPi as neuroprotective agents may offer a new therapeutic alternative for neurodegenerative disorders. An ideal PARPi needs to inhibit PARP-1 hyperactivity while also limiting downstream DNA damage and cellular toxicity-an effect that is attractive in cancer but far from ideal in neurological disease applications. Consequently, in this study, we set out to evaluate the neuroprotective properties of a previously reported low-toxicity PARPi (10e) using in vitro neuronal models of PD. 10e is a structural analogue of FDA-approved PARPi olaparib, with high PARP-1 affinity and selectivity. Our studies revealed that 10e protects neuronal cells from oxidative stress and DNA damage. In addition, 10e exhibits neuroprotective properties against α-synuclein pre-formed fibrils (αSyn PFF) mediated effects, including reduction in the levels of phosphorylated αSyn and protection against abnormal changes in NAD⁺ levels. Our in vitro studies with 10e provide support for repurposing high-affinity and low-toxicity PARPi for neurological applications and lay the groundwork for long-term therapeutic studies in animal models of PD.

Ex vivo expanded patient-derived γδ T-cell immunotherapy enhances neuroblastoma tumor regression in a murine model

An effective therapy regimen for relapsed/refractory high-risk neuroblastoma (NB) includes the anti-GD2 monoclonal antibody, dinutuximab, in combination with temozolomide and irinotecan, supporting a role for chemo-immunotherapy in NB. γδ T cells are an attractive anti-tumor immunotherapy because of their direct cytotoxic activity mediated through cell surface receptors NKG2D and CD16. NKG2D facilitates the innate recognition of stress-induced ligands whereas CD16 recognizes antibody bound to tumors and activates mechanisms of antibody-dependent cellular cytotoxicity (ADCC). This study demonstrates an efficient method for expanding and storing γδ T cells from NB patient-derived apheresis products at clinically relevant amounts. The expanded patient-derived γδ T cells were cytotoxic against the K562 cell line and multiple NB cell lines. Combining γδ T cells with dinutuximab led to a 30% increase in tumor cell lysis compared to γδ T cells alone. Furthermore, low-dose temozolomide in combination with expanded γδ T cells and dinutuximab resulted in increased IFNγ secretion and increased γδ T-cell surface expression of FasL and CD107a. IMR5 NB cell line xenografts established subcutaneously in NSG mice were treated with a regimen of dinutuximab, temozolomide, and γδ T cells. This combination caused targeted killing of NB xenografts in vivo, reducing tumor burden and prolonging survival. These data support the continued preclinical testing of dinutuximab and temozolomide in conjunction with γδ T-cell immunotherapy for patients with recurrent/refractory NB.

Dual Functional Capability of Dendritic Cells - Cytokine-Induced Killer Cells in Improving Side Effects of Colorectal Cancer Therapy

The aim of cancer therapy is to eradicate cancer without affecting healthy tissues. Current options available for treating colorectal cancer (CRC), including surgery, chemotherapy or radiotherapy, usually elicit multiple adverse effects and frequently fail to completely remove the tumor cells. Thus, there is a constant need for seeking cancer cell-specific therapeutics to improve the course of cancer therapy and reduce the risk of relapse. In this review we elaborate on the mechanisms underlying the immunotherapy with dendritic cells (DCs) and cytokine-induced killer (CIK) cells, and summarize their effectiveness and tolerability available clinical studies. Finally, we discuss the up-to-date combinatorial adoptive anti-cancer immunotherapy with CIK cells co-cultured with DCs that recently showed encouraging efficacy and usefulness in treating malignant disease, including CRC.

Immunological and Translational Aspects of NK Cell-Based Antitumor Immunotherapies

Natural killer (NK) cells play a pivotal role in the first line of defense against cancer. NK cells that are deficient in CD3 and a clonal T cell receptor (TCR) can be subdivided into two major subtypes, CD56^dimCD16⁺ cytotoxic and CD56^brightCD16⁻ immunoregulatory NK cells. Cytotoxic NK cells not only directly kill tumor cells without previous stimulation by cytotoxic effector molecules, such as perforin and granzymes or via death receptor interactions, but also act as regulatory cells for the immune system by secreting cytokines and chemokines. The aim of this review is to highlight therapeutic strategies utilizing autologous and allogenic NK cells, combinations of NK cells with monoclonal antibodies to induce antibody-dependent cellular cytotoxicity, or immune checkpoint inhibitors. Additionally, we discuss the use of chimeric antigen receptor-engineered NK cells in cancer immunotherapy.

A Multidrug-resistant Engineered CAR T Cell for Allogeneic Combination Immunotherapy

The adoptive transfer of chimeric antigen receptor (CAR) T cell represents a highly promising strategy to fight against multiple cancers. The clinical outcome of such therapies is intimately linked to the ability of effector cells to engraft, proliferate, and specifically kill tumor cells within patients. When allogeneic CAR T-cell infusion is considered, host versus graft and graft versus host reactions must be avoided to prevent rejection of adoptively transferred cells, host tissue damages and to elicit significant antitumoral outcome. This work proposes to address these three requirements through the development of multidrug-resistant T cell receptor αβ-deficient CAR T cells. We demonstrate that these engineered T cells displayed efficient antitumor activity and proliferated in the presence of purine and pyrimidine nucleoside analogues, currently used in clinic as preconditioning lymphodepleting regimens. The absence of TCRαβ at their cell surface along with their purine nucleotide analogues-resistance properties could prevent their alloreactivity and enable them to resist to lymphodepleting regimens that may be required to avoid their ablation via HvG reaction. By providing a basic framework to develop a universal T cell compatible with allogeneic adoptive transfer, this work is laying the foundation stone of the large-scale utilization of CAR T-cell immunotherapies.

Retrospective comparative study of the effects of dendritic cell vaccine and cytokine-induced killer cell immunotherapy with that of chemotherapy alone and in combination for colorectal cancer

Purpose. This retrospective study determined the delayed-type hypersensitivity (DTH) skin test and safety of dendritic cell (DC) vaccine and cytokine-induced killer (CIK) cell immunotherapy and the survival compared to chemotherapy in 239 colorectal cancer (CRC) patients. Methods. DTH and safety of the immunotherapy were recorded. The overall survival (OS) and disease free survival curves were compared according to the immunotherapy and/or chemotherapy received with Kaplan-Meier estimates. Results. Of the 70 patients who received immunotherapy, 62.86% had a positive DTH skin test, 38.57% developed fever, 47.14% developed insomnia, 38.57% developed anorexia, 4.29% developed joint soreness, and 11.43% developed skin rash. For 204 resectable CRC patients, median survival time (MST) (198.00 days) was significantly longer in patients with immunotherapy plus chemotherapy than with chemotherapy alone (106.00 days) (P = 0.02). For 35 patients with unresectable or postsurgery relapsed CRC and who were confirmed to be dead, no statistical difference was observed in the MST between the patients treated with immunotherapy and with chemotherapy (P = 0.41). MST in the patients treated with chemotherapy plus immunotherapy was 154 days longer than that of patients treated with chemotherapy alone (P = 0.41). Conclusions. DC vaccination and CIK immunotherapy did not cause severe adverse effects, induce immune response against CRC, and prolong OS.

Co-culture with NK-92MI cells enhanced the anti-cancer effect of bee venom on NSCLC cells by inactivation of NF-κB

In the present study we experimented on a multimodal therapeutic approach, such as combining chemotherapy agent (Bee venom) with cellular (NK-92MI) immunotherapy. Previously bee venom has been found to show anti-cancer effect in various cancer cell lines. In lung cancer cells bee venom showed an IC(50) value of 3 μg/ml in both cell lines. The co-culture of NK-92MI cell lines with lung cancer cells also show a decrease in viability upto 50 % at 48 h time point. Hence we used bee venom treated NK-92MI cells to co-culture with NSCLC cells and found that there is a further decrease in cell viability upto 70 and 75 % in A549 and NCI-H460 cell lines respectively. We further investigated the expression of various apoptotic and anti-apoptotic proteins and found that Bax, cleaved caspase-3 and -8 were increasing where as Bcl-2 and cIAP-2 was decreasing. The expression of various death receptor proteins like DR3, DR6 and Fas was also increasing. Concomitantly the expression of various death receptor ligands (TNFalpha, Apo3L and FasL) was also increasing of NK-92MI cells after co-culture. Further the DNA binding activity and luciferase activity of NF-κB was also inhibited after co-culture with bee venom treated NK-92MI cell lines. The knock down of death receptors with si-RNA has reversed the decrease in cell viability and NF-κB activity after co-culture with bee venom treated NK-92MI cells. Thus this new approach can enhance the anti-cancer effect of bee venom at a much lower concentration.

Engineered drug resistant γδ T cells kill glioblastoma cell lines during a chemotherapy challenge: a strategy for combining chemo- and immunotherapy

Classical approaches to immunotherapy that show promise in some malignancies have generally been disappointing when applied to high-grade brain tumors such as glioblastoma multiforme (GBM). We recently showed that ex vivo expanded/activated γδ T cells recognize NKG2D ligands expressed on malignant glioma and are cytotoxic to glioma cell lines and primary GBM explants. In addition, γδ T cells extend survival and slow tumor progression when administered to immunodeficient mice with intracranial human glioma xenografts. We now show that temozolomide (TMZ), a principal chemotherapeutic agent used to treat GBM, increases the expression of stress-associated NKG2D ligands on TMZ-resistant glioma cells, potentially rendering them vulnerable to γδ T cell recognition and lysis. TMZ is also highly toxic to γδ T cells, however, and to overcome this cytotoxic effect γδ T cells were genetically modified using a lentiviral vector encoding the DNA repair enzyme O(6)-alkylguanine DNA alkyltransferase (AGT) from the O(6)-methylguanine methyltransferase (MGMT) cDNA, which confers resistance to TMZ. Genetic modification of γδ T cells did not alter their phenotype or their cytotoxicity against GBM target cells. Importantly, gene modified γδ T cells showed greater cytotoxicity to two TMZ resistant GBM cell lines, U373(TMZ-R) and SNB-19(TMZ-R) cells, in the presence of TMZ than unmodified cells, suggesting that TMZ exposed more receptors for γδ T cell-targeted lysis. Therefore, TMZ resistant γδ T cells can be generated without impairing their anti-tumor functions in the presence of high concentrations of TMZ. These results provide a mechanistic basis for combining chemotherapy and γδ T cell-based drug resistant cellular immunotherapy to treat GBM.