FOXM1 regulates radiosensitivity of lung cancer cell partly by upregulating KIF20A

Forkhead box protein M1 (FOXM1), an important regulator of tumorigenesis in various human tumors, has recently been reported to play a role in the modulation of radiosensitivity in glioma and breast cancer cells. The present study aimed to investigate the effects of FOXM1 on radiotherapy resistance in human lung cancer and to explore the related molecular mechanisms. The results revealed that FOXM1 expression was upregulated in A549 and H1299 cells after IR (Ionizing radiation). FOXM1 inhibition impeded survival fractions, impeded proliferation, and triggered apoptosis after IR. Moreover, the silencing of FOXM1 dampened cell migration, invasion, and EMT (epithelial-mesenchyman transition) in A549 and H1299 cells treated by IR. In addition, KIF20A was also highly expressed in IR-treated A549 cells and downregulated by FOXM1 inhibition. Knockdown of KIF20A inhibited the survival fraction. Reintroduction of KIF20A partly reversed the effects of FOXM1 on the proliferation, apoptosis, and metastasis of A549 cells. Taken together, these results indicated that FOXM1 might enhance radioresistance partly through the induction of KIF20A expression.

Impact of the Intra- and Inter-observer Variability in the Delineation of Parotid Glands on the Dose Calculation During Head and Neck Helical Tomotherapy

The intra- and inter-observer variability in delineation of the parotids on the kilo-voltage computed tomography (kVCT) and mega-voltage computed tomography (MVCT) were examined to establish their impact on the dose calculation during adaptive head and neck helical tomotherapy (HT). Three observers delineated left and right parotids for ten randomly selected patients with oropharynx cancer treated on HT. The pre-treatment kVCT and the MVCT from the first fraction of irradiation were selected to delineation. The delineation procedure was repeated three times by each observer. The parotids were delineated according to the institutional protocol. The analyses included intra-observer reproducibility and inter-structure, -observer and -modality variability of the volume and dose. The differences between the left and right parotid outlines were not statistically significant (p > 0.3). The reproducibility of the delineation was confirmed for each observer on the kVCT (p > 0.2) and on the MVCT (p > 0.1). The inter-observer variability of the outlines was significant (p < 0.001) as well as the inter-modality variability (p < 0.006). The parotids delineated on the MVCT were 10% smaller than on the kVCT. The inter-observer variability of the parotids delineation did not affect the average dose (p = 0.096 on the kVCT and p = 0.176 on the MVCT). The dose calculated on the MVCT was higher by 3.3% than dose from the kVCT (p = 0.009). Usage of the institutional protocols for the parotids delineation reduces intra-observer variability and increases reproducibility of the outlines. These protocols do not eliminate delineation differences between the observers, but these differences are not clinically significant and do not affect average doses in the parotids. The volumes of the parotids delineated on the MVCT are smaller than on the kVCT, which affects the differences in the calculated doses.