Evaluation of Radiotherapy on miR-374 Gene Expression in Colorectal Cancer Patient Blood Samples.

Background: Current cancer treatments include surgery, radiotherapy, chemotherapy, and immunotherapy. Despite these treatments, a main issue in cancer treatment is early detection. microRNAs (miRNAs) can be used as markers to diagnose and treat cancers. This study investigated the effect of radiotherapy on miR-374 expression, and APC and GSK-3ß, two of its target genes, in the WNT pathway, in peripheral blood samples from radiotherapy-treated colorectal cancer (CRC) patients. Methods: Peripheral blood was collected from 25 patients before and after radiotherapy. RNA was extracted from the blood and cDNA synthesized. miR-374, APC, and GSK-3ß expression was determined by real-time polymerase chain reaction (RT-PCR) and the amplicons were sequenced. Finally, the data were statistically evaluated. Results: Quantitative RT-PCR revealed significant down-regulation of miR-374 (0.63-fold) and up-regulation of APC (1.12-fold) and GSK-3ß (1.22-fold) in CRC patients after five weeks of radiotherapy. Sequencing of PCR-produced amplicons confirmed the conservation of mature and precursor sequences encoding miR-374. miR-374 expression changed with time after radiotherapy treatment and related tumor grading. Increased age and tumor grade positively correlated with decreased miR-374 expression. Conclusion: miR-374 expression, and that of its two target genes, APC and GSK-3ß, changed after radiotherapy. These genes can likely be used as diagnostic radiotherapy markers in CRC.

Concomitant Up-Regulation of Hsa- Mir-374 and Down-Regulation of Its Targets, GSK-3ß and APC, in Tissue Samples of Colorectal Cancer.

BACKGROUND: The WNT-pathway is involved in several cancers, including colorectal cancer (CRC). Many cell signaling components and pathways are controlled by microRNAs. The main purpose of the present study was to investigate the expression of hsa-miR-374, and its two target genes of the Wnt-pathway in CRC clinical samples. METHODS: In this study, we predicted the miRNAs targeting key genes of WNT-pathway using bioinformatics algorithms. The expression levels of hsa-miR-374, APC and GSK-3ß on 48 pairs of Formalin-Fixed Paraffin-Embedded (FFPE) CRC tumors and marginal-tumors were evaluated using real time-PCR. Additionally, the hsa-miR-374a-5p precursor sequence was amplified by whole-blood DNA as a template. This amplicon was cloned into pEGFP-c1 expression vector and transfected into SW742 cells. Aside from this, MTT assay was performed to evaluate the effect of miR-374 on cell viability. RESULTS: The bioinformatics analysis indicated that hsa-miR-374 binds to the regulatory region the key components of WNT-pathway, including APC and GSK-3ß considering the recognition elements and mirSVR scores. Our results revealed significant down-regulation of GSK-3ß (0.94 times, p= 0.0098) and APC (0.96 times, p= 0.03) and up-regulation of miR-374 (1.22 times, p= 0.0071) on tumor samples compared with their normal pairs. Meanwhile, the results of the over-expression of miR-374 showed down-regulation of APC and GSK-3ß. MTT-assay also indicated that the miR-374 increased cell survival. CONCLUSION: The results of our study indicated a concomitant change in the expression of miR-374 and its two related target genes, in clinical samples of CRC. Hsa-miR-374 might be as a helpful biomarker or therapeutic target in CRC.

Comparison of dosimetric parameters of small-field electron beams between Advanced Markus, Semiflex 3D, and Diode E responses.

The usage of dosimetry of small fields in radiotherapy to measure radiation dose is difficult because of high-dose gradients, lateral electronic disequilibrium, and detector volume effects. In this study, three dosimeters namely, Markus, Semiflex 3D, and Diode E were tested using the Elekta-accelerator electron beams. The electron beam parameters, penumbra, and output factor were determined using these dosimeters for each field size and energy. According to the results, Diode E and Advanced Markus exhibited the greatest difference in Rq among the electron beam parameters. Furthermore, the greatest difference in penumbra was observed between Diode E and Advanced Markus for the field size of 3 cm2 at 10 MeV. In terms of output factor, three dosimeters exhibited the greatest difference between Diode E and Advanced Markus for the field size of 3 cm2 at 10 MeV. The findings indicate that the Semiflex 3D can be regarded as an appropriate dosimeter for electron small-field dosimetry.

Comparison of Photon-electron and Photon Radiotherapy for Supraclavicular Lymph Nodes of Mastectomy Patients with Left-sided Breast Cancer.

The aim of radiotherapy is to deliver the highest possible radiation dose to the tumor and the lowest radiation to normal tissues surrounding the tumor. In the present study, lymph nodes of the supraclavicular region were treated using two therapeutic techniques, namely photon technique (PT) and combinatory photon-electron technique (CPET). We recruited 50 patients with local lymph node metastasis. The photon energies were 6-15 MV. Furthermore, the electron beam energy was 18 MeV in CPET. The study findings revealed that the mean delivered dose to target volume was 41.12 ± 2.98Gy for PT and 44.56 ± 1.90Gy for CPET. The percentage of the target volume irradiated to 90% of the prescribed dose (V90) was calculated as 74.61% ± 9.30% and 82.06% ± 9.70% for PT and CPET, respectively. The mean dose delivered to the heart and lungs was not significantly different between the two groups. Furthermore, the maximum doses delivered to the spinal cord were 12.55Gy in PT and 8.89Gy in CPET. The mean doses delivered to the thyroid gland were 39.26 and 34.89Gy in PT and CPET. According to the study results, the maximum doses delivered to the spinal cord, head of the humerus bone, and thyroid were reduced significantly as measured the CPET technique. In contrast, no significant difference was observed regarding the dose delivered to the heart and lung. The dose delivered to the supraclavicular region determined by the CPET was significantly augmented. Furthermore, the coverage of the tumor mass was optimized using the new method.