Suppression of DNMT1 combined with ATM or ATR inhibitor as a therapeutic combination of acute myeloid leukemia

The potential treatment option of targeting DNA methyltransferase 1 (DNMT1) has been explored, but further investigation is required to assess the efficacy of combination therapy in acute myeloid leukemia (AML). In this study, bioinformatics and online databases were utilized to select the combined therapeutic targets. The potential kinases associated with DNMT1-related genes in AML were analyzed using the Cancer Genome Atlas (TCGA) database and X2K Appyter (Expression2Kinases) database. In-vitro evaluations were conducted to assess the synergistic effects between DNMT1 and ATR/ATM in five AML cell lines (MOLM-16, NB-4, HEL 92.1.7, HEL, EOL-1). In our study, ATR and ATM are primarily the kinases associated with DNMT1-related genes in AML. We observed a significant upregulation of DNMT1, ATR, and ATM expression in AML tissues and cell lines. The five AML cell lines demonstrated sensitivity to monotherapy with GSK-368, AZD-1390, or AZD-6738 (EC50 value ranges from 5.461 to 7.349 nM, 5.821 to 10.120 nM, and 7.618 to 10.100 nM, respectively). A considerable synergistic effect was observed in AML cell lines when combining GSK-368 and AZD-1390, GSK-368 and AZD-6738, or AZD-1390 and AZD-6738, resulting in induced cell apoptosis and inhibited cell growth. DNMT1, ATM, and ATR possess potential as therapeutic targets for AML. Both individual targeting and combination targeting of these molecules have been confirmed as promising therapeutic approaches for AML.

Insight into the Progress in CAR-T Cell Therapy and Combination with Other Therapies for Glioblastoma

Glioblastoma (GBM) is the most common malignant primary brain cancer in adults. It is always resistant to existing treatments, including surgical resection, postoperative radiotherapy, and chemotherapy, which leads to a dismal prognosis and a high relapse rate. Therefore, novel curative therapies are urgently needed for GBM. Chimeric antigen receptor T (CAR-T) cell therapy has significantly improved life expectancy for hematological malignancies patients, and thus it increases the interest in applying CAR-T cell therapy for solid tumors. In the recently published research, it is indicated that there are numerous obstacles to achieve clinical benefits for solid tumors, especially for GBM, because of GBM anatomical characteristics (the blood-brain barrier and suppressive tumor microenvironment) and the tumor heterogeneity. CAR-T cells are difficult to penetrate blood-brain barrier, and immunosuppressive tumor microenvironment (TME), which induces CAR-T cell exhaustion, impairs CAR-T cell therapy response. Moreover, under the pressure of CAR-T cell therapy, the tumor heterogeneity and tumor plasticity drive tumor evolution and therapy resistance, such as antigen escape. Nonetheless, scientists strive for strategies to overcome these hurdles, including novel CAR-T cell designs and regional delivery. For instance, the structure of multi-antigen-targeted CAR-T cells can enrich CAR-T accumulation in tumor TME and eliminate abundant tumor cells to avoid tumor antigen heterogeneity. Additionally, paired with an immune modifier and one or more stimulating domains, different generation of innovations in the structure and manufacturing of CAR-T cells have improved efficacy and persistence. While single CAR-T cell therapy receives limited clinical survival benefit. Compared with single CAR-T cell therapy, the combination therapies have supplemented the treatment paradigm. Combinatorial treatment methods consolidate the CAR-T cells efficacy by regulating the tumor microenvironment, optimizing the CAR structure, targeting the CAR-T cells to the tumor cells, reversing the tumor-immune escape mechanisms, and represent a promising avenue against GBM, based on multiple impressive research. Moreover, exciting results are also reported to be realized through combining effective therapies with CAR-T cells in preclinical and clinical trials samples, have aroused inspiration to explore the antitumor function of combination therapies. In summary, this study aims to summarize the limitation of CAR-T cell therapies and introduces novel strategies to enhance CAR-T cell function as well as prospect the potential of the therapeutic combination.

Autophagy inhibition overcomes sorafenib resistance in S45F-mutated desmoid tumors

BACKGROUND

Desmoid tumors (DTs) are rare and understudied fibroblastic lesions that are frequently recurrent and locally invasive. DT patients often experience chronic pain, organ dysfunction, decrease in quality of life, and even death.

METHODS

Sorafenib has emerged as a promising therapeutic strategy, which has led to the first randomized phase 3 clinical trial devoted to DTs. Concurrently, we conducted a comprehensive analysis of sorafenib efficacy in a large panel of desmoid cell strains to probe for response mechanism.

RESULTS

We found distinctive groups of higher- and lower-responder cells. Clustering the lower-responder group, we observed that CTNNB1 mutation was determinant of outcome. Our results revealed that a lower dose of sorafenib was able to inhibit cell viability, migration, and invasion of wild-type and T41A-mutated DTs. Apoptosis induction was observed in those cells after treatment with sorafenib. On the other hand, the lower dose of sorafenib was not able to inhibit cell viability, migration, or invasion or to induce apoptosis in the S45F-mutated DTs. The investigation of autophagy showed the dependency of S45F-mutated DTs on this pathway as a part of cell survival mechanism. Significantly, when autophagy was inhibited genetically or pharmacologically in the S45F mutant cell strains, sensitivity to sorafenib was restored.

CONCLUSIONS

Our findings suggest that the response to sorafenib differs when comparing S45F-mutated DTs and T41A-mutated or wild-type DTs. Furthermore, the combination of hydroxychloroquine and sorafenib enhances the antiproliferative and proapoptotic effects in S45F-mutated DT cells, suggesting that profiling β-catenin status could guide clinical management of desmoid patients who are considering sorafenib treatment.