Selective degradation of PL2L60 by metabolic stresses­induced autophagy suppresses multi­cancer growth.

It has been reported that PL2L60 proteins, a product of PIWIL2 gene which might be activated by an intragenic promoter, could mediate a common pathway specifically for tumorigenesis. In the present study, it was further identified by using western blot assay that the PL2L60 proteins could be degraded in cancer cells through a mechanism of selective autophagy in response to oxidative stress. The PL2L60 was downregulated in various types of cancer cells under the hypoxic condition independently of HIF­1α, resulting in apoptosis of cancer cells. Inhibition of autophagy by small interfering RNA targeting of either Beclin­1 (BECN1) or Atg5 resulted in restoration of PL2L60 expression in hypoxic cancer cell. The hypoxic degradation of PL2L60 was also blocked by the attenuation of the autophagosome membrane protein Atg8/microtubule­associated protein 1 light chain 3 (LC3) or autophagy cargo protein p62 expression. Surprisingly, Immunofluorescence analysis demonstrated that LC3 could be directly bound to PL2L60 and was required for the transport of PL2L60 from the nucleus to the cytoplasm for lysosomal flux under basal or activated autophagy in cancer cells. Moreover, flow cytometric analysis displayed that knocking down of PL2L60 mRNA but not PIWIL2 mRNA effectively inhibited cancer cell proliferation and promoted apoptosis of cancer cells. The similar results were obtained from in vivo tumorigenic experiment, in which PL2L60 downregulation in necroptosis areas was confirmed by immunohistochemistry. These results suggested that various cancer could be suppressed by promoting autophagy. The present study revealed a key role of autophagic degradation of PL2L60 in hypoxia­induced cancer cell death, which could be used as a novel therapeutic target of cancer.

Clinical application of amplification-based versus amplification-free metagenomic next-generation sequencing test in infectious diseases.

Background: Recently, metagenomic next-generation sequencing (mNGS) has been used in the diagnosis of infectious diseases (IDs) as an emerging and powerful tool. However, whether the complicated methodological variation in mNGS detections makes a difference in their clinical performance is still unknown. Here we conducted a method study on the clinical application of mNGS tests in the DNA detection of IDs. Methods: We analyzed the effect of several potential factors in the whole process of mNGS for DNA detection on microorganism identification in 98 samples of suspected ID patients by amplification-based mNGS. The amplification-based and amplification-free mNGS tests were successfully performed in 41 samples. Then we compared the clinical application of the two mNGS methods in the DNA detection of IDs. Results: We found that a higher concentration of extracted nucleic acid was more conducive to detecting microorganisms. Other potential factors, such as read depth and proportion of human reads, might not be attributed to microorganism identification. The concordance rate of amplification-based and amplification-free mNGS results was 80.5% (33/41) in the patients with suspected IDs. Amplification-based mNGS showed approximately 16.7% higher sensitivity than amplification-free mNGS. However, 4 cases with causative pathogens only detected by amplification-based mNGS were finally proved false-positive. In addition, empirical antibiotic treatments were adjusted in 18 patients following mNGS testing with unexpected pathogens. Conclusions: Amplification-based and amplification-free mNGS tests showed their specific advantages and disadvantages in the diagnosis of IDs. The clinical application of mNGS still needs more exploration from a methodological perspective. With advanced technology and standardized procedure, mNGS will play a promising role in the diagnosis of IDs and help guide the use of antibiotics.

An asymmetrically dimethylarginated nuclear 90 kDa protein (p90aDMA) induced by interleukin (IL)-2, IL-4 or IL-6 in the tumor microenvironment is selectively degraded by autophagy.

Protein arginine methylation is a common posttranslational modification resulting in the generation of asymmetric dimethylarginine (aDMA) and symmetric dimethylarginine (sDMA). Currently, the regulation of aDMA or sDMA by hypoxia, nutrient stavation or cytokines in the tumor microenvironment remains largely unknown. Here we show that p90aDMA, p70aDMA and p90sDMA, endogenous proteins containing aDMA or sDMA with mass 70 or 90 kDa, were widely and dominantly expressed in breast cancer cell lines. Notably, it was p90aDMA rather than p90sDMA that accumulated in the nucleus upon stimulation of cancer cells with interleukin (IL)-2, IL-4, IL-6 but not IL-8. In addition, the p90aDMA accumulation could be inhibited after treatment with a global methyltrasferase inhibitor, adenosine-2',3'-dialdehyde (AdOx). It seemed that some endogenous proteins in cancer cells were asymmetrically arginine-methylated upon exposure to some cytokines.. Furthermore, endogenous proteins of aDMA, such as p90aDMA and p70aDMA, were degraded in response to hypoxia, nutrient starvation and rapamycin treatment in breast and cervical cancer cells. IL-2/4/6 slightly increased basal autophagy but slightly decreased the rapamycin­induced autophagy in cancer cells, suggesting that IL-2/4/6 and autophagy inducers play distinct roles in the regulation of aDMA of proteins. Conversely, rapamycin accumulated p90sDMA in MDA-MB­231 and MCF-7 cells. Taken together, our results add a new dimension to the complexity of arginine methylated regulation in response to various stimuli and provide the first evidence that aDMA serves as one specific degradation signal of selective autophagy.

[Application of direct demodulation technique in analysis of ground verification test of x-ray spectrometer for Chang'e mission].

An X-ray fluorescence imaging spectrometer based on silicon PIN photodiodes was designed and constructed for the Chang'E mission, the first lunar spacecraft, and will be in operation at a 200 km circular lunar orbit with one year lifetime. The X-ray fluorescence spectrometer consists of two silicon PIN photodiodes modules, each holds two low energy detector units to analyze the distribution of useful elements and to estimate the abundance on the moon, which is one of the objectives of the X-ray fluorescence spectrometer experiment. The low energy detector unit is 25 mm2, 500 microm thick, with the energy band of 1-10 keV, and energy resolution of: approximately 5% at 5.9 keV. The ground verification tests of the X-ray spectrometer for Chang' E mission were introduced in the present paper. Taking the energy response matrix of the spectrometer as the foundation and using the direct demodulation technique and fundamental parameter method, the authors performed some quantitative and qualitative analysis of these scientific data which came from the ground verification tests, especially for Mg, Al and Si elements.