RESUMO
Adoptive cell transfer (ACT) with neoantigen-reactive T lymphocytes can mediate cancer regression. Here we isolated unique, personalized, neoantigen-reactive T cell receptors (TCRs) from tumor-infiltrating lymphocytes of patients with metastatic gastrointestinal cancers and incorporated the TCR α and ß chains into gamma retroviral vectors. We transduced autologous peripheral blood lymphocytes and adoptively transferred these cells into patients after lymphodepleting chemotherapy. In a phase 2 single-arm study, we treated seven patients with metastatic, mismatch repair-proficient colorectal cancers who had progressive disease following multiple previous therapies. The primary end point of the study was the objective response rate as measured using RECIST 1.1, and the secondary end points were safety and tolerability. There was no prespecified interim analysis defined in this study. Three patients had objective clinical responses by RECIST criteria including regressions of metastases to the liver, lungs and lymph nodes lasting 4 to 7 months. All patients received T cell populations containing ≥50% TCR-transduced cells, and all T cell populations were polyfunctional in that they secreted IFNγ, GM-CSF, IL-2 and granzyme B specifically in response to mutant peptides compared with wild-type counterparts. TCR-transduced cells were detected in the peripheral blood of five patients, including the three responders, at levels ≥10% of CD3+ cells 1 month post-ACT. In one patient who responded to therapy, ~20% of CD3+ peripheral blood lymphocytes expressed transduced TCRs more than 2 years after treatment. This study provides early results suggesting that ACT with T cells genetically modified to express personalized neoantigen-reactive TCRs can be tolerated and can mediate tumor regression in patients with metastatic colorectal cancers. ClinicalTrials.gov registration: NCT03412877 .
RESUMO
Pancreatic adenocarcinoma (PDAC) epitomizes a deadly cancer driven by abnormal KRAS signaling. Here, we show that the eIF4A RNA helicase is required for translation of key KRAS signaling molecules and that pharmacological inhibition of eIF4A has single-agent activity against murine and human PDAC models at safe dose levels. EIF4A was uniquely required for the translation of mRNAs with long and highly structured 5' untranslated regions, including those with multiple G-quadruplex elements. Computational analyses identified these features in mRNAs encoding KRAS and key downstream molecules. Transcriptome-scale ribosome footprinting accurately identified eIF4A-dependent mRNAs in PDAC, including critical KRAS signaling molecules such as PI3K, RALA, RAC2, MET, MYC, and YAP1. These findings contrast with a recent study that relied on an older method, polysome fractionation, and implicated redox-related genes as eIF4A clients. Together, our findings highlight the power of ribosome footprinting in conjunction with deep RNA sequencing in accurately decoding translational control mechanisms and define the therapeutic mechanism of eIF4A inhibitors in PDAC. SIGNIFICANCE: These findings document the coordinate, eIF4A-dependent translation of RAS-related oncogenic signaling molecules and demonstrate therapeutic efficacy of eIF4A blockade in pancreatic adenocarcinoma.