No abstract

No abstract

BACKGROUND:The aim of this phase 2 study was to determine the long-term local control, survival, and late toxicities among patients with locally advanced nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT) with the simultaneous modulated accelerated radiation therapy (SMART) boost technique and concurrent chemotherapy. METHODS: Eighty-one patients with pathologically diagnosed locally advanced NPC were enrolled in this study. IMRT was delivered with the SMART boost technique at prescribed doses of 68 grays (Gy)/30 fraction to the nasopharynx gross target volume. Concurrent cisplatin chemotherapy (80 mg/m 2 /d on Days 1 and 22) was administered. RESULTS: The mean actual physical dose delivered to the nasopharynx gross target volume was 73.8 Gy, and the mean biologically effective dose (BED) for the nasopharynx gross target volume was 84.8 Gy. With a median follow-up of 54 months, 4 (4.9%) patients experienced local recurrence. The 5-year local control rate was 94.9%. Eighteen patients died. Among them, 66.7% died of distant metastasis. The 5-year disease-free and overall survivals were 76.7% and 74.5%, respectively. The most common late toxicities among 68 patients with !4 years follow-up were grade 1-2 xerostomia, hearing loss, skin dystrophy, and subcutaneous fibrosis. No grade 4 late toxicities were noted. CONCLUSIONS: IMRT with SMART to enhance BED and concurrent chemotherapy is feasible in patients with locally advanced NPC. Long-term results showed excellent local control with fewer late toxicities, although no further improvement was noted in overall survival, and the major cause of death was distant metastasis. Exploration of more effective combined chemoradiation strategies is warranted.

No abstract

No abstract

No abstract

SUMMARY The Mre11/Rad50/NBS1 (MRN) complex is thought to be a critical sensor that detects damaged DNA and recruits ATM to DNA foci for activation. However, it remains to be established how the MRN complex regulates ATM recruitment to the DNA foci during DNA double-strand breaks (DSBs). Here we show that Skp2 E3 ligase is a key component for the MRN complex-mediated ATM activation in response to DSBs. Skp2 interacts with NBS1 and triggers K63-linked ubiquitination of NBS1 upon DSBs, which is critical for the interaction of NBS1 with ATM, thereby facilitating ATM recruitment to the DNA foci for activation. Finally, we show that Skp2 deficiency exhibits a defect in homologous recombination (HR) repair, thereby increasing IR sensitivity. Our results provide molecular insights into how Skp2 and the MRN complex coordinate to activate ATM, and identify Skp2-mediatetd NBS1 ubiquitination as a vital event for ATM activation in response to DNA damage.

The serine/threonine kinase Akt plays a central role in cell proliferation, survival and metabolism and its hyperactivation is linked to cancer progression. Here we report that Akt undergoes K64 methylation by SETDB1, which is crucial for cell membrane recruitment, phosphorylation and activation of Akt upon growth factor stimulation. Furthermore, we reveal an adaptor function of histone demethylase JMJD2A, which recognizes Akt K64 methylation and recruits E3 ligase TRAF6 and Skp2-SCF to the Akt complex, independently of its demethylase activity, thereby initiating K63-linked ubiquitination, cell membrane recruitment and activation of Akt. Notably, cancer associated Akt mutant (E17K) displays enhanced K64 methylation, leading to its hyper-phosphorylation and activation. SETDB1-mediated Akt K64 methylation is upregulated and correlated with Akt hyperactivation in non-small-cell lung carcinoma (NSCLC), promotes tumor development and predicts poor outcome. Collectively, these findings reveal complicated layers of Akt activation regulation coordinated by SETDB1-mediated Akt K64 methylation to drive tumorigenesis.