Bench to Beside and Back translational immuno-onocology-Cures

Division Of Basic Sciences - Nci

Investigators

Abstract

Four CCR projects are currently supported by this Cancer Moonshot Bench to Beside and Back award: 1. TME informed NK cell therapy for pediatric sarcomas, led by Rosandra Kaplan (CCR) and Timothy Cripe (Nationwide Children's Hospital). The overall goal of this project is to develop natural killer (NK) cell therapy with TGF-beta imprinting that can be augmented through manipulation of the immune suppressive tumor microenvironment (TME) leading to improved NK cell-mediated anti-tumor immunity, and serves as a potential effective therapy for patients with relapsed pediatric sarcoma. Bone and soft tissue sarcomas are one of the most common solid tumors in pediatric, adolescent/young adult (AYA) patients. Despite improved outcomes due to advances in surgical local control and multi-agent chemotherapy, prognosis for patients who develop recurrent, metastatic, or refractory disease remains poor. For these patients, new therapeutic approaches are urgently needed. The team at Nationwide Children's Hospital (NCH) has developed a genetically modified feeder cell line that enables extensive ex vivo propagation of highly-active human NK cells from various sources, and this methodology has been evaluated in early-phase clinical trials for hematologic malignancies and brain tumors. 2. Targeting neuroendocrine tumors with DLK1 directed immunotherapy, led by Nitin Roper (CCR) and John Maris (CHOP). During the first year of the BtB award we have focused on Aim 1 of our proposal: defining the anti-tumor activity of ADCT-701, a novel antibody drug conjugate targeting DLK1, in neuroendocrine neoplams. In particular, the goal of Aim 1 was to assess whether there is activity of ADCT-701 beyond neuroblastoma, which has been the focus of Dr. Maris' laboratory, our extramural collaborator. The results of our experiments in Year 1 demonstrate evidence of ADCT-701 anti-tumor activity in multiple ACC pre-clinical models. Thus, based on these data, ACC is an indication in our upcoming clinical trial: "A First in Human Phase I Trial with ADCT-701 in Neuroendocrine Neoplasms". The IND for ADCT-701 has been FDA approved and we expect to enroll patients in this clinical trial later this year. 3. B2B and Back: CD22 and CD19/22 CAR immunotherapies for childhood leukemia, led by Naomi Taylor (CCR) and Crystal Mackall (Stanford). The Taylor and Mackall teams are carrying out clinical trials with identical CD22 and CD19/CD22-bivalent CAR vectors but the two sites are using different manufacturing procedures to generate the CAR-transduced T cells that are being infused into patients. The current proposal is to test the hypothesis that variability in CAR-T cell immunotherapeutic potential is affected by variations in manufacturing platforms and can be predicted through evaluation of antigen-dependent CAR-T cell activity. High throughput analyses of these parameters will be leveraged to optimize CAR manufacturing, evaluate divergent patient outcomes, and enhance durable responses in pediatric leukemia patients. 4. Alternative splicing of CD22 following Inotuzumab, led by Nirali Shah (CCR) and Andrei Thomas-Tikhonenko (CHOP). Recent work from the Thomas-Tikhonenko lab has shown that CD22 protein expression is highly dependent on the inclusion of exon 2, which is where the open reading frame begins (Zheng et al., 2022). When exon 2 inclusion is negatively affected by aberrant splicing, the number of transcripts capable of being translated is significantly decreased, resulting in the emergence of CD22-low variants. To identify suitable experimental models for mechanistic studies, we quantitated total expression and reads spanning different exon 1 junctions in a panel of lymphoid cell lines from the Cancer Cell Line Encyclopedia (Ghandi et al., 2019). We observed that widely used NALM6 and REH cell lines differ in the relative abundance of the exon 2-skipping/non-coding CD22 mRNA variants, which were prominent in the former but not the latter. Using sgRNAs from the well-validated pooled Brunello library (Sanson et al. 2018) in NALM6 and REH cell lines we identified dozens of positive and negative regulators of CD22 expression that passed our stringent false discovery rate (FDR) cut-offs, with the CD22 gene predictably being the most significant regulator of its own protein expression. Further up on the list are known B cell-specific transcription factors PAX5 and EBF1, but also several RNA-binding proteins with potential roles in splicing. We are currently in the process of cross-referencing them with top correlates of CD22 exon 2 inclusion in B-ALL samples from the NCI. However, we are also prioritizing targets based on their known involvement in mRNA splicing as well as potential druggability.