Search bioRxiv⌕ Search

bioRxiv · 10.1101/642934

Overcoming Immunological Resistance Enhances the Efficacy of a Novel anti-tMUC1 CAR T Cell Treatment Against Pancreatic Ductal Adenocarcinoma

Abstract

Chimeric antigen receptor engineered T cells (CAR T cells) have shown remarkable success in treating hematologic cancers. However, this efficacy has yet to translate to treatment in solid tumors. Pancreatic ductal adenocarcinoma (PDA) is a fatal malignancy with poor prognosis. Treatment options are limited and commonly associated with severe side effects. We have developed and characterized a second generation CAR engineered T cell using the light and heavy chain sequence derived from a novel monoclonal antibody, TAB004, that specifically binds the tumor associated antigen, tMUC1. tMUC1 is overexpressed in varying levels on ~85% of all human PDA. We present data showing that the TAB004 derived CAR T cells (tMUC1-CAR T cells) specifically bind to tMUC1 on PDA cells and is cytotoxic against the majority of the PDA cell lines. The tMUC1-CAR T cells do not bind or kill normal epithelial cells. We further demonstrate that the tMUC1-CAR T cells control the growth of orthotopic pancreatic tumors in vivo. PDAs are generally cold tumors with resistance to many standard treatment modalities, thus, it was not surprising that some of the PDA cell lines were refractory to CAR T cell treatment. qPCR analysis of several genes known to be associated with immune resistance revealed overexpression of indoleamine 2, 3-dioxygenases-1 (IDO1), Cyclooxygenase 1 and 2 (COX1 and COX2), Adenosine deaminases acting on RNA (ADAR1) and galectin-9 (Gal-9). We treated resistant PDA cells with a combination of CAR T cells and biological inhibitors of IDO1, COX1/2, ADAR1, and Gal-9. Results showed a significant enhancement of CAR T cell cytotoxicity against PDA cells when inhibiting IDO1, COX1/2, and Gal-9 but not ADAR1 or COX2. Overcoming CAR T cell resistance in PDA is a significant advancement in the field and may lead to future combination therapies that are less toxic but more efficient against this deadly disease.

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Yazdanifar, M., Zhou, R., Grover, P., Williams, C., Bose, M., Moore, L. J., Wu, S.-t., Chi, R., Maher, J., Dreau, D., Mukherjee, P.. 2019-05-20. Overcoming Immunological Resistance Enhances the Efficacy of a Novel anti-tMUC1 CAR T Cell Treatment Against Pancreatic Ductal Adenocarcinoma. https://doi.org/10.1101/642934

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

The methionine cycle sustains the mesenchymal phenotype of tumor cells and drives PDA progression

Mesenchymal traits are associated with poor prognosis in Pancreatic Ductal Adenocarcinoma (PDA), but direct targeting of mesenchymal tumor cells remains a challenge. Metabolic profiling of tumor cells isolated from murine PDA and liver metastases (LM) revealed that LM rely more on the methionine cycle than does primary PDA. This metabolic shift was specifically associated with increased activation of the methionine cycle in mesenchymal tumor cells compared to differentiated tumor cells. We show that the targeting of the key enzyme of the methionine cycle S-adenosylhomocysteine hydrolase (SAHH) in mesenchymal cells lowers the levels of homocysteine (Hcy) and glutathione, resulting in reduced antioxidant capacity, deregulated intracellular calcium homeostasis, and ultimately loss of mesenchymal markers. Together, these events decrease cell proliferation and invasion, blunting the tumorigenic and metastatic potential of SAHH-deficient cells, eventually impeding tumor growth and progression of the metastatic disease. Clinically, the high expression of SAHH in patients with mesenchymal PDA is correlated with poor survival, positioning SAHH as a potential therapeutic target to impede the pro-metastatic, mesenchymal phenotype of PDA.

cancer biology↗

Arrest-associated transcriptional programmes outweigh apoptosis-associated programmes in treatment-naive pancreatic ductal adenocarcinoma

Background: Pancreatic ductal adenocarcinoma (PDAC) is driven by mutant KRAS, and RAS inhibitors now extend survival in previously treated metastatic disease. Whether treatment shrinks a tumour or only halts its growth depends partly on whether cancer cells die or stop dividing, yet how untreated PDAC cells are balanced between these programmes is unknown. Aims: We aimed to characterise the balance between apoptosis-associated and arrest-associated transcriptional programmes in treatment-naive PDAC and to examine their relationships with tumour subtype, TGM2 expression, tissue organisation, survival and drug sensitivity. Methods and results: We scored 52,999 malignant cells from 18 untreated patients in the Hwang atlas using a transcriptional contrast between genes associated with apoptosis and genes associated with resistance to apoptosis or cell-cycle arrest. In every patient the contrast was shifted toward the arrest-associated side: using equality between the two sides as the dividing threshold, 86.3% of cells with an informative score fell on that side, although the proportion depends on the threshold chosen. The shift recurred in the independent Steele atlas (median 71.6% per sample, range 37.1% to 90.8%). In the discovery cohort, tumours with higher basal-like scores had fewer arrest-side cells, and TGM2 expression was modestly higher on the arrest-associated side in both cohorts. The contrast did not track cell-line drug sensitivity or survival in bulk tumours. Conclusion: Untreated PDAC cells show a reproducible transcriptional bias toward anti-apoptotic and cell-cycle-arrest programmes. Whether this bias predicts cellular responses to treatment remains to be tested.

cancer biology↗

Quantitative live imaging reveals region-dependent medulloblastoma disseminationin the zebrafish brain

Medulloblastoma is the most common malignant pediatric brain tumor, and relapse is frequently driven by dissemination within the central nervous system. Yet the early dynamics of tumor spread remain difficult to resolve in vivo. Here, we orthotopically transplanted human medulloblastoma cells into larval zebrafish and followed individual xenografts by longitudinal high-resolution confocal imaging. ONS-76 showed particularly robust dissemination, with hindbrain tumors spreading into the developing cerebellum in 81.5% of larvae, more than fourfold the frequency observed for forebrain or midbrain tumors. Disseminating cells extended along brain-surface and leptomeningeal-like regions and frequently associated with cerebral vasculature. Quantitative analysis of tumor area, perimeter, compactness, convex hull area, and fractal dimension captured changes in growth and spatial complexity over time. Dasatinib reduced tumor expansion and dissemination-related features in a concentration-dependent manner, while higher doses revealed host toxicity. These findings establish a powerful in vivo model for resolving medulloblastoma dissemination and therapeutic response.

cancer biology↗