Human mitochondrial pyrroline-5-carboxylate reductase 1 promotes invasiveness and impacts survival in breast cancers.

Human mitochondrial pyrroline-5-carboxylate reductase (PYCR) is a house-keeping enzyme that catalyzes the reduction of Δ1-pyrroline-5-carboxylate to proline. This enzymatic cycle plays pivotal roles in amino acid metabolism, intracellular redox potential and mitochondrial integrity. Here, we hypothesize that PYCR1 might be a novel prognostic biomarker and therapeutic target for breast cancer. In this study, breast cancer tissue samples were obtained from Zhejiang University (ZJU set). Immunohistochemistry analysis was performed to detect the protein level of PYCR1, and Kaplan-Meier and Cox proportional analyses were employed in this outcome study. The prognostic significance and performance of PYCR1 mRNA were validated on 13 worldwide independent microarray data sets, composed of 2500 assessable breast cancer cases. Our findings revealed that both PYCR1 mRNA and protein expression were significantly associated with tumor size, grade and invasive molecular subtypes of breast cancers. Independent and pooled analyses verified that higher PYCR1 mRNA levels were significantly associated with poor survival of breast cancer patients, regardless of estrogen receptor (ER) status. For in vitro studies, inhibition of PYCR1 by small-hairpin RNA significantly reduced the growth and invasion capabilities of the cells, while enhancing the cytotoxicity of doxorubicin in breast cancer cell lines MCF-7 (ER positive) and MDA-MB-231 (ER negative). Further population study also validated that chemotherapy significantly improved survival in early-stage breast cancer patients with low PYCR1 expression levels. Therefore, PYCR1 might serve as a prognostic biomaker for either ER-positive or ER-negative breast cancer subtypes and can also be a potential target for breast cancer therapy.

A case study of evaluating bilateral lung dose for VMAT treatment planning using a partial sagittal arc.

Radiation pneumonitis (RP) is a potential toxic side effect of thoracic radiotherapy. Optimal planning techniques must maintain tumor coverage while limiting dose to normal lung tissue to reduce the risk of patients developing RP. The addition of a noncoplanar arc may be beneficial by increasing treatment angles and providing an ideal dose distribution for tumor coverage while decreasing dose to organs at risk (OAR). The purpose of this research was to compare the effects on the normal bilateral lung tissue receiving 20 Gy, 10 Gy and 5 Gy (V20, V10, V5) and the mean lung dose (MLD) values when medial lung tumors are treated with 3 partial coplanar arcs vs 2 partial coplanar arcs combined with a partial sagittal arc. Researchers hypothesized that a beam arrangement of 2 partial coplanar arcs and 1 partial sagittal arc would reduce V20, V10, V5, and MLD values when compared to a 3 partial coplanar arc plan. In a retrospective study of 5 patients with bulky, medial right lung lesions without nodal involvement, cases were planned with both a noncoplanar and a coplanar arc geometry. Results were evaluated using a two-tailed t-test to determine the statistical significance (p < 0.05) of changes to total lung volume analyzation metrics when a noncoplanar sagittal arc was incorporated compared to the standard lung treatment using only coplanar arcs. Although some patient cases showed minor improvement in the V20, V10, V5, and MLD metrics, the study results were not statistically significant and showed no advantage with the introduction of an anterior sagittal arc over a coplanar beam arrangement.

Human Mitotic Centromere-Associated Kinesin Is Targeted by MicroRNA 485-5p/181c and Prognosticates Poor Survivability of Breast Cancer.

PURPOSE: This study aims to evaluate the prognostic value of human Mitotic Centromere-Associated Kinesin (MCAK), a microtubule-dependent molecular motor, in breast cancers. The posttranscriptional regulation of MCAK by microRNAs will also be explored. METHODS: The large-scale gene expression datasets of breast cancer (total n=4,677) were obtained from GEO, NKI, and TCGA database. Kaplan-Meier and Cox analyses were used for survival analysis. MicroRNAs targeting MCAK were predicted by bioinformatic analysis and validated by a dual-luciferase reporter assay. RESULTS: The expression of MCAK was significantly associated with aggressive features of breast cancer, including tumor stage, Elston grade, and molecular subtypes, for global gene expression datasets of breast cancer (p<0.05). Overexpression of MCAK was significantly associated with poor outcome in a dose-dependent manner for either ER-positive or ER-negative breast cancer. Evidence from bioinformatic prediction, coexpression assays, and gene set enrichment analyses suggested that miR-485-5p and miR-181c might target MCAK and suppress its expression. A 3'UTR dual-luciferase target reporter assay demonstrated that miR-485-5p and miR-181c mimics specifically inhibited relative Firefly/Renilla luciferase activity by about 50% in corresponding reporter plasmids. Further survival analysis also revealed that miR-485-5p (HR=0.59, 95% CI 0.37-0.92) and miR-181c (HR=0.54, 95% CI 0.34-0.84) played opposite roles of MCAK (HR=2.80, 95% CI 1.77-4.57) and were significantly associated with better outcome in breast cancers. CONCLUSION: MCAK could serve as a prognostic biomarker for breast cancers. miR-485-5p and miR-181c could specifically target and suppress the MCAK gene expression in breast cancer cells.

Fabrication of all-transparent polymer-based and encapsulated nanofluidic devices using nano-indentation lithography.

In this paper, we describe a novel and simple process for the fabrication of all-transparent and encapsulated polymeric nanofluidic devices using nano-indentation lithography. First, a nanomechanical probe is used to 'scratch' nanoscale channels on polymethylmethacrylate (PMMA) substrates with sufficiently high hardness. Next, polydimethylsiloxane (PDMS) is used twice to duplicate the nanochannels onto PDMS substrates from the 'nano-scratched' PMMA substrates. A number of experiments are conducted to explore the relationships between the nano-indentation parameters and the nanochannel dimensions and to control the aspect ratio of the fabricated nanochannels. In addition, traditional photolithography combined with soft lithography is employed to fabricate microchannels on another PDMS 'cap' substrate. After manually aligning the substrates, all uncovered channels on two separate PDMS substrates are bonded to achieve a sealed and transparent nanofluidic device, which makes the dimensional transition from microscale to nanoscale feasible. The smallest dimensions of the achievable nanochannels that we have demonstrated thus far are of ~20 nm depth and ~800 nm width, with lengths extendable beyond 100 µm. Fluid flow experiments are performed to verify the reliability of the device. Two types of colloidal solution are used to visualize the fluid flow through the nanochannels, that is, ethanol is mixed with gold colloid or fluorescent dye (fluorescein isothiocyanate), and the flow rate and filling time of liquid in the nanochannels are estimated based on time-lapsed image data. The simplicity of the fabrication process, bio-compatibility of the polymer substrates, and optical transparency of the nanochannels for flow visualization are key characteristics of this approach that will be very useful for nanofluidic and biomolecular research applications in the future.