Intratumoral Delivery of Chimeric Antigen Receptor T Cells Targeting CD133 Effectively Treats Brain Metastases.

PURPOSE: Brain metastases (BM) are mainly treated palliatively with an expected survival of less than 12 months after diagnosis. In many solid tumors, the human neural stem cell marker glycoprotein CD133 is a marker of a tumor-initiating cell population that contributes to therapy resistance, relapse, and metastasis. EXPERIMENTAL DESIGN: Here, we use a variant of our previously described CD133 binder to generate second-generation CD133-specific chimeric antigen receptor T cells (CAR-T) to demonstrate its specificity and efficacy against multiple patient-derived BM cell lines with variable CD133 antigen expression. RESULTS: Using both lung- and colon-BM patient-derived xenograft models, we show that a CD133-targeting CAR-T cell therapy can evoke significant tumor reduction and survival advantage after a single dose, with complete remission observed in the colon-BM model. CONCLUSIONS: In summary, these data suggest that CD133 plays a critical role in fueling the growth of BM, and immunotherapeutic targeting of this cell population is a feasible strategy to control the outgrowth of BM tumors that are otherwise limited to palliative care. See related commentary by Sloan et al., p. 477.

CD70 as an actionable immunotherapeutic target in recurrent glioblastoma and its microenvironment.

PURPOSE: Glioblastoma (GBM) patients suffer from a dismal prognosis, with standard of care therapy inevitably leading to therapy-resistant recurrent tumors. The presence of cancer stem cells (CSCs) drives the extensive heterogeneity seen in GBM, prompting the need for novel therapies specifically targeting this subset of tumor-driving cells. Here, we identify CD70 as a potential therapeutic target for recurrent GBM CSCs. EXPERIMENTAL DESIGN: In the current study, we identified the relevance and functional influence of CD70 on primary and recurrent GBM cells, and further define its function using established stem cell assays. We use CD70 knockdown studies, subsequent RNAseq pathway analysis, and in vivo xenotransplantation to validate CD70's role in GBM. Next, we developed and tested an anti-CD70 chimeric antigen receptor (CAR)-T therapy, which we validated in vitro and in vivo using our established preclinical model of human GBM. Lastly, we explored the importance of CD70 in the tumor immune microenvironment (TIME) by assessing the presence of its receptor, CD27, in immune infiltrates derived from freshly resected GBM tumor samples. RESULTS: CD70 expression is elevated in recurrent GBM and CD70 knockdown reduces tumorigenicity in vitro and in vivo. CD70 CAR-T therapy significantly improves prognosis in vivo. We also found CD27 to be present on the cell surface of multiple relevant GBM TIME cell populations, notably putative M1 macrophages and CD4 T cells. CONCLUSION: CD70 plays a key role in recurrent GBM cell aggressiveness and maintenance. Immunotherapeutic targeting of CD70 significantly improves survival in animal models and the CD70/CD27 axis may be a viable polytherapeutic avenue to co-target both GBM and its TIME.

A Missing Link: Engagements of Dendritic Cells in the Pathogenesis of SARS-CoV-2 Infections.

Dendritic cells (DC) connect the innate and adaptive arms of the immune system and carry out numerous roles that are significant in the context of viral disease. Their functions include the control of inflammatory responses, the promotion of tolerance, cross-presentation, immune cell recruitment and the production of antiviral cytokines. Based primarily on the available literature that characterizes the behaviour of many DC subsets during Severe acute respiratory syndrome (SARS) and coronavirus disease 2019 (COVID-19), we speculated possible mechanisms through which DC could contribute to COVID-19 immune responses, such as dissemination of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to lymph nodes, mounting dysfunctional inteferon responses and T cell immunity in patients. We highlighted gaps of knowledge in our understanding of DC in COVID-19 pathogenesis and discussed current pre-clinical development of therapies for COVID-19.

Strategies to Enhance the Efficacy of T-Cell Therapy for Central Nervous System Tumors.

Mortality rates in patients diagnosed with central nervous system (CNS) tumors, originating in the brain or spinal cord, continue to remain high despite the advances in multimodal treatment regimens, including surgery, radiation, and chemotherapy. Recent success of adoptive cell transfer immunotherapy treatments using chimeric antigen receptor (CAR) engineered T cells against in chemotherapy resistant CD19 expressing B-cell lymphomas, has provided the foundation for investigating efficacy of CAR T immunotherapies in the context of brain tumor. Although significant efforts have been made in developing and translating the novel CAR T therapies for CNS tumors, including glioblastoma (GBM), researchers are yet to achieve a similar level of success as with liquid malignancies. In this review, we discuss strategies and considerations essential for developing robust preclinical models for the translation of T cell-based therapies for CNS tumors. Some of the key considerations include route of delivery, increasing persistence of T cells in tumor environment, remodeling of myeloid environment, establishing the window of treatment opportunity, harnessing endogenous immune system, designing multiple antigen targeting T cells, and rational combination of immunotherapy with the current standard of care. Although this review focuses primarily on CAR T therapies for GBM, similar strategies, and considerations are applicable to all CNS tumors in general.

The Rational Development of CD133-Targeting Immunotherapies for Glioblastoma.

CD133 marks self-renewing cancer stem cells (CSCs) in a variety of solid tumors, and CD133+ tumor-initiating cells are known markers of chemo- and radio-resistance in multiple aggressive cancers, including glioblastoma (GBM), that may drive intra-tumoral heterogeneity. Here, we report three immunotherapeutic modalities based on a human anti-CD133 antibody fragment that targets a unique epitope present in glycosylated and non-glycosylated CD133 and studied their effects on targeting CD133+ cells in patient-derived models of GBM. We generated an immunoglobulin G (IgG) (RW03-IgG), a dual-antigen T cell engager (DATE), and a CD133-specific chimeric antigen receptor T cell (CAR-T): CART133. All three showed activity against patient-derived CD133+ GBM cells, and CART133 cells demonstrated superior efficacy in patient-derived GBM xenograft models without causing adverse effects on normal CD133+ hematopoietic stem cells in humanized CD34+ mice. Thus, CART133 cells may be a therapeutically tractable strategy to target CD133+ CSCs in human GBM or other treatment-resistant primary cancers.

Oncolytic measles virus therapy enhances tumor antigen-specific T-cell responses in patients with multiple myeloma.

Oncolytic virus therapy leads to immunogenic death of virus-infected tumor cells and this has been shown in preclinical models to enhance the cytotoxic T-lymphocyte response against tumor-associated antigens (TAAs), leading to killing of uninfected tumor cells. To investigate whether oncolytic virotherapy can increase immune responses to tumor antigens in human subjects, we studied T-cell responses against a panel of known myeloma TAAs using PBMC samples obtained from ten myeloma patients before and after systemic administration of an oncolytic measles virus encoding sodium iodide symporter (MV-NIS). Despite their prior exposures to multiple immunosuppressive antimyeloma treatment regimens, T-cell responses to some of the TAAs were detectable even before measles virotherapy. Measurable baseline T-cell responses against MAGE-C1 and hTERT were present. Furthermore, MV-NIS treatment significantly (P < 0.05) increased T-cell responses against MAGE-C1 and MAGE-A3. Interestingly, one patient who achieved complete remission after MV-NIS therapy had strong baseline T-cell responses both to measles virus proteins and to eight of the ten tested TAAs. Our data demonstrate that oncolytic virotherapy can function as an antigen agnostic vaccine, increasing cytotoxic T-lymphocyte responses against TAAs in patients with multiple myeloma, providing a basis for continued exploration of this modality in combination with immune checkpoint blockade.

Development of a standardized flow cytometric method to conduct longitudinal analyses of intracellular CD3ζ expression in patients with head and neck cancer.

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common neoplasm in the world. The follow-up protocols currently available do not appear to diagnose treatment failures and recurrences early enough to provide the best treatment to improve the survival rates of patients. The identification of biomarkers may aid in diagnosing, monitoring the progression, or predicting treatment outcomes in HNSCC. The present study aimed to evaluate whether cluster of differentiation (CD) 3ζ chain expression may serve as a biomarker for the early detection of recurrent or persistent HNSCC. However, in a longitudinal study, a standardized method that allows consistent data comparisons in an inter-assay manner is critical. The present study reveals a method to monitor expression levels of CD3ζ over multiple time-points using flow cytometry. The present study validated the use of an internal control and normalization procedure for tracking alterations in CD3ζ expression in samples from patients with HNSCC, which were collected and assayed for a longitudinal study.

Change in CD3ζ-chain expression is an independent predictor of disease status in head and neck cancer patients.

CD3ζ has emerged as a clinically important immunological marker in head and neck squamous cell carcinoma (HNSCC) with reduced level of expression reported in both tumor infiltrating lymphocytes and peripheral blood lymphocytes. In this prospective study (power = 0.99, α = 0.05), CD3ζ expression was compared in 47 HNSCC patients and 53 controls using standardized flow cytometric method. There was no statistical difference in the percentages of the CD3 ε+ T-cell subset present in the peripheral blood mononuclear cells of the HNSCC patients and the healthy controls; however, T cells from the HNSCC patients produced a significantly weaker IFN-γ response in comparison to the healthy controls, when they were stimulated by the recall viral CEF peptide antigen. All patients were followed up for at least 3 years with a median follow-up of 45 months. Levels of CD3ζ-chain expression were measured at 117 follow-up visits at six-month intervals. Receiver operating characteristic curve identified the optimal cut off as a 12% increase in post treatment CD3ζ-chain expression from the baseline levels to confirm absence of HNSCC with the area under curve of 0.81 (95% CI = 0.68-0.94) for predicting absence of HNSCC. The specificity, sensitivity and positive predictive value were 81.25% 79.21% and 97.56%, respectively. Three-year disease specific survival (DSS) was significantly lower (p = 0.007) at 63.2% for patients who showed <12% increase in CD3ζ-chain level as compared to 96.2% for patients who had ≥12% increase. Our results indicate that the change in CD3ζ-chain expression from the baseline is an independent predictor of residual and recurrent HNSCC.

Bidirectional interactions of NK cells and dendritic cells in immunotherapy: current and future perspective.

NK cells and dendritic cells (DC) are innate cellular components that regulate adaptive immune responses in the immune surveillance of cancer and infections. Interactions of NK and DC are bidirectional. In this mini review, we summarized how NK cells regulate immature DC editing and maturation, how DC regulate NK-cell functions reciprocally in the NK-DC crosstalk, and the importance of NK-DC crosstalk in antitumor immunity. Enhancing NK-DC crosstalk by cellular factor(s), antibodies or creating a microenvironment that promote NK activations, DC maturation and NK-DC crosstalk will provide new insights into future development of DC-based immunotherapy.

Lentiviral vector-based therapy in head and neck cancer (Review).

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common neoplasm worldwide. Despite advances in multimodality treatments involving surgery, radiation and chemotherapy, the five-year survival rate has remained at ~50% for the past 35 years. Therefore, the early detection of recurrent or persistent disease is extremely important. Replication-incompetent HIV-1-based lentiviral vectors have emerged as powerful and safe tools for gene delivery. Commonly, HNSCC is a locoregional disease that presents at or close to the body surface. Thus, HNSCC is amendable to intratumoral injections of gene therapy vectors aimed at correcting defects associated with tumor suppressor genes to induce the direct cytotoxicity of cancer cells or immune modulation to promote antitumor immunity. Current investigations analyzing HNSCC gene mutations and stem cell markers and the cancer immunoediting concept are creating exciting therapeutic opportunities for lentiviral and other gene transfer vectors. The present review reports specific examples of the current applications of lentiviral vectors in HNSCC.