XBP1s activates METTL3/METTL14 for ER-phagy and paclitaxel sensitivity regulation in breast cancer.

Cancer cells employ the unfolded protein response (UPR) or induce autophagy, especially selective removal of certain ER domains via reticulophagy (termed ER-phagy), to mitigate endoplasmic reticulum (ER) stress for ER homeostasis when encountering microenvironmental stress. N6-methyladenosine (m6A) is one of the most abundant epitranscriptional modifications and plays important roles in various biological processes. However, the molecular mechanism of m6A modification in the ER stress response is poorly understood. In this study, we first found that ER stress could dramatically elevate m6A methylation levels through XBP1s-dependent transcriptional upregulation of METTL3/METTL14 in breast cancer (BC) cells. Further MeRIP sequencing and relevant validation results confirmed that ER stress caused m6A methylation enrichment on target genes for ER-phagy. Mechanistically, METTL3/METTL14 increased ER-phagy machinery formation by promoting m6A modification of the ER-phagy regulators CALCOCO1 and p62, thus enhancing their mRNA stability. Of note, we further confirmed that the chemotherapeutic drug paclitaxel (PTX) could induce ER stress and increase m6A methylation for ER-phagy. Furthermore, the combination of METTL3/METTL14 inhibitors with PTX demonstrated a significant synergistic therapeutic effect in both BC cells and xenograft mice. Thus, our data built a novel bridge on the crosstalk between ER stress, m6A methylation and ER-phagy. Most importantly, our work provides novel evidence of METTL3 and METTL14 as potential therapeutic targets for PTX sensitization in breast cancer.

Tadalafil increases the antitumor activity of 5-FU through inhibiting PRMT5-mediated glycolysis and cell proliferation in colorectal cancer.

BACKGROUND: Protein arginine methyltransferase 5 (PRMT5) is upregulated in multiple tumors and plays a pivotal role in cancer cell proliferation. However, the role of PRMT5 in colorectal cancer remains poorly understood. METHODS: We detected the expression level of PRMT5 and glycolytic enzymes using online databases and colorectal cancer cell lines by immunohistochemical staining, quantitative real-time polymerase chain reaction (qRT-PCR), and western blotting. And MTT and colony formation assays were conducted to investigate cell proliferation. Then, we evaluated ECAR and OCR levels using a biological energy analyzer to investigate the energy status of colorectal cancer, and the transcriptional regulation was detected by dual luciferase reporter assay and ChIP assay. Finally, the efficacy of combined treatment of tadalafil and 5-FU was verified. RESULTS: PRMT5 was highly expressed in colorectal cancer tissues compared with their normal counterparts and correlated with poor prognosis in CRC patients. Then, we demonstrated that PRMT5 knockdown or loss of function attenuated the viability of CRC cells, while overexpression of PRMT5 promoted cell proliferation. Mechanistically, PRMT5 enhanced glycolysis through transcriptionally activating LDHA expression. In addition, the PRMT5 inhibitor, tadalafil, rendered CRC cells sensitive to antitumor agent 5-FU in vitro and in vivo. CONCLUSIONS: Our data indicates that PRMT5 promoted colorectal cancer proliferation partially through activating glycolysis and may be a potential target for colorectal cancer therapy.

Quantitative proteomic analyses of Schistosoma japonicum in response to artesunate.

Artesunate (ART) has high prophylactic efficacy against Schistosoma japonicum infections and has been used to treat and prevent schistosomiasis in China since 1995. However, the molecular mechanism of ART's effects on S. japonicum remains unclear. Herein, we applied isobaric tagging reagents for relative and absolute quantification analyses coupled with two-dimensional liquid chromatography and tandem mass spectrometry to investigate the effect of ART on the proteome of S. japonicum in susceptible mice. 4529 proteins were quantified on the basis of 21,825 unique peptides. Comparative proteomic analyses revealed that 145, 228 and 185 proteins were significantly differentially expressed after ART treatment in schistosomula, juvenile and adult worms, respectively. Ninety proteins were differentially expressed between each two treatment groups in response to ART treatment: 67 proteins were associated with S. japonicum development/aging and 23 were specifically associated with ART treatment. Quantitative real-time PCR of selected genes verified the proteomic data. Gene ontology annotation and Kyoto encyclopedia of genes and genomes pathway mapping analysis showed that the majority of differentially expressed proteins were involved in stress/defense/detoxification, signal transduction, carbohydrate metabolism, amino acid metabolism, transcription/translation, and protein synthesis/assembly/degradation. Thirty-four of the proteins differentially expressed under ART treatment encoded hypothetical, uncharacterized proteins with unknown functions. This study obtained the first comprehensive protein expression profile of S. japonicum in response to ART, and provides a basis for a better understanding of the molecular mechanisms of ART effects on S. japonicum.

Molecular identification of Anisakis and Hysterothylacium larvae in marine fishes from the East China Sea and the Pacific coast of central Japan.

Anisakiasis is a human disease caused by the accidental ingestion of larvae belonging to the family Anisakidae. Three fish species, the small yellow croaker Pseudosciaena polyactis, the mackerel Pneumatophorus japonicus and the hairtail Trichiurus haumela are important source for food products in the East China Sea. The prevalence and the identification of Anisakidae larvae in these fishes will benefit the prevention and control of anisakiasis. In this study, fish samples were obtained from fish markers in the East China Sea and the Pacific coast of central Japan during April 2011 and July 2013. For species identification, the PCR-based restriction fragment length polymorphism (PCR-RFLP) analysis of the entire ITS region (ITS1, 5.8 S and ITS2) of nuclear ribosomal DNA (rDNA) was performed. In total, 2004 larvae were collected from 80 hairtail fish, 20 small yellow croaker, and 27 mackerel from the East China Sea and the Pacific coast of central Japan. High prevalence of Anisakidae larvae infection (116/122, 95.1%) was detected in the East China Sea. Seven species were identified belonging to the genera Anisakis (Nematoda: Anisakidae) and Hysterothylacium (Nematoda: Anisakidae). Anisakis pegreffii was the predominant species accounting for 84.8% of all larvae examined in East China Sea, while all Anisakidae larvae isolated from Japan were identified as Anisakis simplex sensu stricto (s.s.). In the East China Sea, A. simplex s.s. and Anisakis typica were 0.6% (4/619) and 1.5% (9/619) of the identified nematodes, respectively. Interestingly, one larva was identified as a recombinant genotype of A. simplex s.s. and A. pegreffii. In addition, four species of the genus Hysterothylacium, namely, Hysterothylacium amoyense (31/619, 5.0%), Hysterothylacium aduncum (10/619, 1.6%), Hysterothylacium fabri (21/619, 3.4%) and Hysterothylacium spp. (18/619, 2.9%) were also identified in the present study. This is a comprehensive epidemiological dataset for the family Anisakidae in the East China Sea. The identification of A. typica, recombinant genotype of A. simplex s.s. and A. pegreffii, H. amoyense and H. fabri is first reported in this area. The wide diversity and substantial geographical distributions of these nematodes will provide a foundation for future studies of Anisakidae family. The high prevalence of these nematodes in marine fishes off the East China Sea may pose considerable food safety problems, which is a potential cause of human anisakiasis.