Circular RNA PIP5K1A promotes colon cancer development through inhibiting miR-1273a.

BACKGROUND: Circular RNAs (circRNAs) are considered to be highly stable due to the closed structure, which are predominately correlated with the development and progression of a wide variety of cancers. Colon cancer is one of the most common malignancies worldwide. A recent study demonstrated the upregulated expression of circPIP5K1A in non-small cell lung cancer. However, few studies have investigated the relationship between circ_0014130 level and colon cancer. Therefore, elucidating the underlying mechanisms of circPIP5K1A's role may help with the identification of novel diagnostic and therapeutic targets for colon cancer. AIM: To investigate the status of circPIP5K1A in colon cancers and its effects on the modulation of cancer development. METHODS: The expression level of circPIP5K1A in tissue and serum samples from colon cancer patients, as well as human colonic cancer cell lines was detected by real-time quantitative reverse transcription-polymerase chain reaction. Following the transfection of specifically synthesized small interfering RNA (siRNA) into colon cell lines, we used Hoechst staining assay to measure the ratio of cell death in the absence of circPIP5K1A. Moreover, we also used the Transwell assay to assess the migratory function of colon cells overexpressing circPIP5K1A. Additionally, we employed a series of bioinformatics prediction programs to predict the potential of circPIP5K1A-targeted miRNAs and mRNAs. The miR-1273a vector was constructed, and then transfected with or without circPIP5K1A vector into colon cancer cells. Afterwards, the expression of activator protein 1 (AP-1), interferon regulating factor 4 (IRF-4), caudal type homeobox 2 (CDX-2), and zinc finger of the cerebellum 1 (Zic-1) was detected by western blotting. RESULTS: CircPIP5K1A was significantly upregulated in colon cancer tissue relative to their adjacent normal tissues. Knockdown of circPIP5K1A in colon cancer cells impaired cell viability and suppressed cell invasion and migration, while enforced expression of circPIP5K1A exhibited the opposite effects on cell migration. Bioinformatics prediction program predicted that the association of circPIP5K1A with miR-1273a, as well as AP-1, IRF-4, CDX-2, and Zic-1. Subsequent studies showed that overexpression of circPIP5K1A augmented the expression of AP-1 but attenuated the expression of IRF-4, CDX-2, and Zic-1. Reciprocally, overexpression of miR-1273a abrogated the oncogenic function of circPIP5K1A in colon cancers. CONCLUSION: Overall, our data demonstrate the oncogenic role of circPIP5K1A-miR-1273a axis in regulation of colon cancer development, which provides a novel insights into colon cancer pathogenesis.

Target volume and position variations during intensity-modulated radiotherapy for patients with nasopharyngeal carcinoma.

PURPOSE: Considerable anatomical changes occur during intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC). This study aimed to quantify volumetric and positional variations of the target volume during IMRT. MATERIALS AND METHODS: Twenty patients with locally advanced NPC who received concurrent (13 patients) or sequential (seven patients) chemoradiotherapy were prospectively recruited and underwent planning computed tomography (CT) and six repeat CTs (every five fractions). Each repeat CT was rigidly registered to the planning CT. Gross tumor volume (GTV) and elective clinical target volume (CTV) were manually delineated on each axial CT image. CTVs of the primary tumor and lymph nodes were expanded with 5 mm margins to corresponding GTVs, with necessary modifications. Volume loss, system and random errors, and the mean and three-dimensional vector displacements were calculated and compared statistically. RESULTS: Volumes of the primary tumor and small (>1 cm, ≤3 cm) and large (>3 cm) positive neck lymph nodes decreased at a rate of 2.6%, 3.7%, and 3.9% per treatment day, respectively. CTVs of the primary tumor, lymph nodes, and elective region decreased 1.5%, 2.3%, and 0.3% per treatment day, respectively. Average displacements of the GTVs and CTVs were <1.3 mm in all directions. GTVs and CTVs of the large and small lymph nodes shifted medially by 0.8-1.3 and 0.6-1.2 mm, respectively, on average. Average three-dimensional displacements of the GTVs and CTVs were 3.4-4.3 mm and 2.5-3.7 mm, respectively. Volume loss and displacements in most directions were significantly larger in patients receiving concurrent chemoradiotherapy than in those receiving sequential therapy. Volume loss and displacements of the GTV of large nodes and elective CTV were significantly larger in male than in female patients. CONCLUSION: Volumetric and positional changes of the target volume were considerable, and volume loss increased as treatment time elapsed during IMRT for NPC.

Anterior myocardial territory may replace the heart as organ at risk in intensity-modulated radiotherapy for left-sided breast cancer.

PURPOSE: We investigated whether the heart could be replaced by the anterior myocardial territory (AMT) as the organ at risk (OAR) in intensity-modulated radiotherapy (IMRT) of the breast for patients with left-sided breast cancer. METHODS AND MATERIALS: Twenty-three patients with left-sided breast cancer who received postoperative radiation after breast-conserving surgery were studied. For each patient, we generated five IMRT plans including heart (H), left ventricle (LV), AMT, LV+AMT, and H+LV as the primary OARs, respectively, except both lungs and right breast, which corresponded to IMRT(H), IMRT(LV), IMRT(AMT), IMRT(LV+AMT), and IMRT(H+LV). For the planning target volumes and OARs, the parameters of dose-volume histograms were compared. RESULTS: The homogeneity index, conformity index, and coverage index were not compromised significantly in IMRT(AMT), IMRT(LV) and IMRT(LV+ AMT), respectively, when compared with IMRT(H). The mean dose to the heart, LV, and AMT decreased 5.3-21.5% (p < 0.05), 19.9-29.5% (p < 0.05), and 13.3-24.5% (p < 0.05), respectively. Similarly, the low (e.g., V5%), middle (e.g., V20%), and high (e.g., V30%) dose-volume of the heart, LV, and AMT decreased with different levels. The mean dose and V10% of the right lung increased by 9.2% (p < 0.05) and 27.6% (p < 0.05), respectively, in IMRT(LV), and the mean dose and V5% of the right breast decreased significantly in IMRT(AMT) and IMRT(LV+AMT). IMRT(AMT) was the preferred plan and was then compared with IMRT(H+LV); the majority of dose-volume histogram parameters of OARs including the heart, LV, AMT, both lungs, and the right breast were not statistically different. However, the low dose-volume of LV increased and the middle dose-volume decreased significantly (p < 0.05) in IMRT(AMT). Also, those of the right lung (V10%, V15%) and right breast (V5%, V10%) decreased significantly (p < 0.05). CONCLUSIONS: The AMT may replace the heart as the OAR in left-sided breast IMRT after breast-conserving surgery to decrease the radiation dose to the heart.

Dosimetric comparison of intensity-modulated radiotherapy plans, with or without anterior myocardial territory and left ventricle as organs at risk, in early-stage left-sided breast cancer patients.

PURPOSE: We evaluated heart sparing using an intensity-modulated radiotherapy (IMRT) plan with the left ventricle (LV) and/or the anterior myocardial territory (AMT) as additional organs at risk (OARs). METHODS AND MATERIALS: A total of 10 patients with left-sided breast cancer were selected for dosimetric planning. Both lungs, the right breast, heart, LV, and AMT were defined as OARs. We generated one tangential field plan and four IMRT plans for each patient. We examined the dose-volume histogram parameters of the planning target volume and OARs. RESULTS: Compared with the tangential field plan, the mean dose to the heart in the IMRT plans did not show significant differences; however, the dose to the AMT and LV decreased by 18.7-45.4% and 10.8-37.4%, respectively. The maximal dose to the heart decreased by 18.6-35.3%, to the AMT by 22.0-45.1%, and to the LV by 23.5-45.0%, And the relative volumes of the heart (V≥12), AMT (V>11) and LV (V>10) decreased significantly with different levels, respectively. The volume of the heart, AMT, LV, both lungs, and right breast receiving≥5 Gy showed a significant increase. Compared with the IMRT (H) plan, the mean dose to the heart, AMT, and LV decreased by 17.5-21.5%, 25.2-29.8%, and 22.8-29.8% and the maximal dose by 13.6-20.6%, 23.1-29.6%, and 17.3-29.1%, respectively. The IMRT plans for both lungs and the right breast showed no significant differences. CONCLUSIONS: The IMRT plans with the addition of the AMT and/or LV as OARs considerably increased heart sparing. We recommend including the LV as an additional OAR in such plans.

[Size effect of Pt nanoparticles: a study of properties of Pt loaded TiO2 thin film].

TiO2 thin films loaded with Pt nanoparticles of different sizes were prepared. The sizes of the Pt nanoparticles were measured by TEM. The TiO2 thin films were characterized using XRD, UV-Vis and photocurrent measurement. The photocatalytic activities of the films were evaluated by the degradation of methylene blue under UV radiation. With the same molar quantity of loaded platinum, the properties of Pt loaded thin films were affected directly by the sizes of platinum nanoparticles, and showed strong size effect. When the particle size was 5 nm, the photocurrent and photocatalytic activity reached the maximum.