No abstract

Significant progress has been made in the diagnosis and treatment of the drugresistant and highly recurrent refractory T cell acute lymphoblastic leukemia (T-ALL). Primary tumor cell-derived induced pluripotent stem cells (iPSCs) have become very useful tumor models for cancer research including drug sensitivity tests. In the present study, we investigated the mechanism underlying drug resistance in T-ALL using the T-ALL-derived iPSCs (T-iPSCs) model. T-ALL cells were transformed using iPSC reprogramming factors (Sox-2, Klf4, Oct4, and Myc) via nonintegrating Sendai virus. T-iPSCs with the Notch1 mutation were then identified through genomic sequencing. Furthermore, T-iPSCs resistant to 80 μM LY411575, a γsecretase and Notch signal inhibitor, were also established. We found a significant difference in the expression of drug resistance-related genes between the drug-resistant T-iPSCs and drug-sensitive groups. Among the 27 genes, six most differently expressed genes (DEGs) based on Log 2 FC >5 were identified. Knockdown analyses using RNA interference (RNAi) revealed that MAEL is the most important gene associated with drug resistance in T-ALL cells. Also, MAEL knockdown downregulated expression of MRP and LRP in drug-resistant T-iPSCs. Interestingly, this phenomenon partially restored the sensitivity of the cells to LY411575. Furthermore, overexpression of the MAEL gene enhanced drug resistance against LY411575. Conclusively, MAEL promotes LY411575 resistance in T-ALL cells increasing the expression of MRP and LRP genes.

The T-cell acute lymphoblastic leukemia (T-ALL) is a kind of hematological malignancy in children. Despite the significant improvement in the cure rate of T-ALL upon treatment with chemotherapy regimens, steroids, and allotransplantation there are relapses. This study focuses on the tumor-specific therapeutic vaccines derived from the induced pluripotent stem cells (iPSC) to address the issue of T-ALL recurrence. Patient-derived tumor cells and healthy donor cells were reprogrammed into the iPSCs and the RNA-seq data of the T-ALL-iPSCs and H-iPSCs were analyzed. In vitro, the whole cell lysate antigens of iPSCs were prepared to induce the dendritic cells (DC) maturation, which in turn stimulated the tumor-specific T cells to kill the T-ALL tumor cells (Jurkat, CCRF-CEM, MOLT-4). The cytotoxic T lymphocyte (CTL) stimulated by the DC-loaded T-ALL-iPSC-derived antigens showed specific cytotoxicity against the T-ALL cells in vitro. In conclusion, the T-ALL-iPSC-based therapeutic cancer vaccine can elicit a specific anti-tumor effect on T-ALL.