Umbelliprenin improved anti-proliferative effects of ionizing radiation on adult T-cell leukemia/lymphoma cells via interaction with CDK6; an in vitro and in silico study.

Adult T-cell leukemia/lymphoma (ATL) is an aggressive malignancy with poor survival rates. The efficacy of radiotherapy in ATL needs enhancement with radiosensitizing agents. This study investigated whether umbelliprenin (UMB) could improve the therapeutic effects of ionizing radiation (IR) in ATL cells. UMB, a naturally occurring prenylated coumarin, exhibits anticancer properties and has shown synergistic effects when combined with chemotherapeutic drugs. Despite this promising profile, there is a notable lack of research on its potential combinatorial effects with IR, particularly for ATL treatment. UMB was extracted from Ferula persica using thin layer chromatography. MT-2 cells were treated with UMB alone and in combination with various doses of IR, and cell proliferation was assessed via alamarBlue assay. Flow cytometry with annexin V and PI staining was conducted, and candidate gene expression was analyzed by qPCR. In silico analysis involved identifying pathogenic targets of ATL, constructing protein-protein interaction (PPI) networks, and evaluating CDK6 expression in MT-2 cells. Molecular docking was used to determine the interaction between UMB and CDK6. The alamarBlue assay and flow cytometry showed that pretreating ATL cells with UMB significantly (p < .0001) enhanced anti-proliferative effects of IR. The combination index indicated a synergistic effect between UMB and IR. qPCR revealed significant (p < .0001) downregulation of CD44, CDK6, c-MYC, and cFLIPL, and overexpression of cFLIPS. Computational analysis identified CDK6 as a hub gene in the PPI network, and CDK6 overexpression was confirmed in MT-2 cells. Molecular docking revealed a favorable binding interaction between UMB and the ATP-binding site of CDK6, with a JAMDA score of -2.131, surpassing the control selonsertib. The current study provides evidence that UMB enhances the anti-proliferative effects of IR on ATL cells, and highlights the significance of targeting CDK6 in combinatorial approaches.

Radiation Response of Human Leukemia/Lymphoma Cells was Improved by 7-Geranyloxycoumarin.

Objectives: Adult T-cell leukemia/lymphoma (ATLL) is a blood neoplasm with specific geographic distribution. Although radiotherapy is a palliative treatment that provides long-term local control, single use of radiation leads to complications for patients. To introduce a novel multimodal approach against ATLL, we investigated combinatorial effects of 7-geranyloxycoumarin and radiation in vitro. Methods: Viability of MT-2 cells was determined by resazurin assay upon administration of 7-geranyloxycoumarin alone and followed by radiation. Then, apoptosis was detected by annexin V and propidium iodide, and the expression of candidate genes was analyzed by qPCR. Results: Findings revealed significant (P<.0001) improvement in radiation effects upon 7-geranyloxycoumarin pretreatment, most notably when cells were pretreated with 5 µg/ml 7-geranyloxycoumarin for 96 h, exposed to 6 Gy radiation and recovered for 48 h. These results were confirmed by flow cytometry, as the percentage of early and late apoptotic cells was increased after combinatorial treatment. In addition, significant (P< .0001) changes in CD44, c-MYC, cFLIPL, BMI-1, NF-κB (Rel A), and P53 expression was induced by 7-geranyloxycoumarin and radiation. Conclusions: Current research indicated, for the first time, that combinatorial use of 7-geranyloxycoumarin and ionizing radiation could be considered as an effective therapeutic modality for ATLL.