Doxorubicin induces drug resistance and expression of the novel CD44st via NF-κB in human breast cancer MCF-7 cells.

CD44, a major receptor for hyaluronan (HA), is a member of a class of adhesion molecules of unknown classification involved in cell proliferation, differentiation, migration, angiogenesis, and the presentation of specific cytokines to the corresponding receptors as well as in cell signaling transduction. It has recently been discovered that CD44, a marker of tumor stem cells, is involved in the drug resistance and invasion of multiple types of tumors. The 20 exons in the CD44 gene that are alternatively spliced, give rise to many CD44 isoforms, possibly including tumor-specific sequences. Dozens of CD44 isoforms have been found, to date, and the standard CD44 (CD44s) isoform is the most common. We recently showed that a novel short-tail isoform of CD44 (CD44st) was expressed in multidrug-resistant human breast cancer MCF-7/Adr cells. Moreover, the novel CD44st was able to interact with HA and regulate the expression of matrix metalloproteinase (MMP)-2 and MMP-9, which increased the invasive capability of MCF-7 cells through the Ras/MAPK signaling pathway. In the present study, we verified that MCF-7 cells subjected to drug pressure develop multidrug resistance to doxorubicin, and the expression levels of multidrug resistance protein 1 (MDR1), CD44st and nuclear factor-κB (NF-κB) mRNA and protein were gradually upregulated in a dose­dependent manner in MCF-7 cells treated with doxorubicin. HA increases the secretion of MMP-2 and MMP-9 in multidrug-resistant MCF-7 cells and affected the invasive ability of MCF-7 cells through the upregulation of CD44st expression, and such an effect was blocked by the NF-κB-specific inhibitor BMS-345541.

The has-miR-526b binding-site rs8506G>a polymorphism in the lincRNA-NR_024015 exon identified by GWASs predispose to non-cardia gastric cancer risk.

Gastric cancer including the cardia and non-cardia types is the second frequent cause of cancer-related deaths worldwide. A subset of non-cardia gastric cancer genetic susceptibility loci have been addressed among Asian through genome-wide association studies (GWASs). This study was to evaluate the effects of single nucleotide polymorphisms (SNPs) of long intergenic non-coding RNAs (lincRNAs) on non-cardia gastric cancer susceptibility in Chinese populations. We selected long intergenic noncoding RNAs (lincRNAs) located in non-cardia gastric cancer risk-related loci and identified 10 SNPs located within lincRNA exonic regions. We examined whether genetic polymorphisms in lincRNAs exons are associated with non-cardia gastric cancer risk in 438 non-cardia gastric cancer patients and 727 control subjects in Chinese populations using logistic regression. Functional relevance was further examined by biochemical assays. We found that lincRNA-NR_024015 rs8506AA carrier was significantly associated with risk of non-cardia gastric cancer (adjusted odds ratio [OR] = 1.56, 95%CI = 1.03-2.39, compared with the rs8506 AG or GG genotype. Further stratification analysis showed that the risk effect was more pronounced in subgroups of smokers (P = 0.001). Biochemical analysis demonstrated that the G to A base change at rs8506G>A disrupts the binding site for has-miR-526b, thereby influencing the transcriptional activity of lincRNA-NR_024015 and affecting cell proliferation. Our present study established a robust association between the rs8506G>A polymorphism in the lincRNA-NR_024015 exon and the risk of non-cardia gastric cancer.

A method for fast automated microscope image stitching.

Image stitching is an important technology to produce a panorama or larger image by combining several images with overlapped areas. In many biomedical researches, image stitching is highly desirable to acquire a panoramic image which represents large areas of certain structures or whole sections, while retaining microscopic resolution. In this study, we develop a fast normal light microscope image stitching algorithm based on feature extraction. At first, an algorithm of scale-space reconstruction of speeded-up robust features (SURF) was proposed to extract features from the images to be stitched with a short time and higher repeatability. Then, the histogram equalization (HE) method was employed to preprocess the images to enhance their contrast for extracting more features. Thirdly, the rough overlapping zones of the images preprocessed were calculated by phase correlation, and the improved SURF was used to extract the image features in the rough overlapping areas. Fourthly, the features were corresponded by matching algorithm and the transformation parameters were estimated, then the images were blended seamlessly. Finally, this procedure was applied to stitch normal light microscope images to verify its validity. Our experimental results demonstrate that the improved SURF algorithm is very robust to viewpoint, illumination, blur, rotation and zoom of the images and our method is able to stitch microscope images automatically with high precision and high speed. Also, the method proposed in this paper is applicable to registration and stitching of common images as well as stitching the microscope images in the field of virtual microscope for the purpose of observing, exchanging, saving, and establishing a database of microscope images.

[Surveillance of cerebral blood circulation changes by transcranial Doppler ultrasonography in patients with nasopharyngeal carcinoma after radiotherapy].

BACKGROUND & OBJECTIVE: Radiotherapy is the first choice for patients with nasopharyngeal carcinoma (NPC), but radiation encephalopathy affects the patients' quality of life significantly. Some research results have showed that the brain damage was associated with radiation-induced cerebral vascular injury. The study was designed to determine the cerebral blood circulation changes in NPC patients pre- and post- radiotherapy using transcranial Doppler ultrasonography (TCD), and to evaluate its value in the early diagnosis and treatment of radiation encephalopathy. METHODS: The blood flow velocity of intra-carotid artery (ICA), middle cerebral artery (MCA), and basal artery (BA) were measured by TCD in 38 patients at the beginning, the end of radiotherapy, 3 months and 3-5 years after radiotherapy respectively. The flow velocity results of each cerebral artery in each examination time after radiotherapy were compared with the findings before treatment correspondingly. RESULTS: The velocity of both side ICA kept stable during all the follow-up time. The mean value of velocity of the left and right MCA raised obviously, from 53-54 cm/s before treatment to 59-60 cm/s at the end of radiotherapy (P< 0.05). It resumed to 54 cm/s after 3 months, and went up again to 57-58 cm/s during 3-5 years after radiotherapy, but there was no remarkable difference in statistics (P >0.05). The mean velocity of BA was 30 cm/s before irradiation, and raised to 35 cm/s at the end of treatment (P< 0.05). After 3 months, it descended to 32 cm/s (P >0.05), and attained to 34 cm/s at 3-5 years after radiotherapy (P< 0.05). CONCLUSION: During several stages of radiotherapy, the flow velocity of MCA and BA were raised obviously in NPC patients.