Serine/arginine-rich splicing factor 7 (SRSF7), a known splicing factor, has been revealed to play oncogenic roles in multiple cancers. However, the mechanisms underlying its oncogenic roles have not been well addressed. Here, based on N⁶-methyladenosine (m⁶A) co-methylation network analysis across diverse cell lines, we find that the gene expression of SRSF7 is positively correlated with glioblastoma (GBM) cell-specific m⁶A methylation. We then indicate that SRSF7 is a novel m⁶A regulator, which specifically facilitates the m⁶A methylation near its binding sites on the mRNAs involved in cell proliferation and migration, through recruiting the methyltransferase complex. Moreover, SRSF7 promotes the proliferation and migration of GBM cells largely dependent on the presence of the m⁶A methyltransferase. The two m⁶A sites on the mRNA for PDZ-binding kinase (PBK) are regulated by SRSF7 and partially mediate the effects of SRSF7 in GBM cells through recognition by insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2). Together, our discovery reveals a novel role of SRSF7 in regulating m⁶A and validates the presence and functional importance of temporal- and spatial-specific regulation of m⁶A mediated by RNA-binding proteins (RBPs).
Humans ; Cell Line, Tumor ; Cell Proliferation ; Gene Expression Regulation, Neoplastic ; Glioblastoma/genetics* ; Methyltransferases/metabolism* ; RNA Splicing Factors/metabolism* ; RNA, Messenger/genetics* ; RNA-Binding Proteins/metabolism* ; Serine-Arginine Splicing Factors/metabolism* ; RNA Methylation/genetics*

Selenylation modification of polysaccharides from the extract residue of Sarcandra glabra(Thunb.) Nakai was operated with sodium selenite as modification agent and barium chloride as the catalyst.The synthesis conditions were optimized by orthogonal experiment with the yields and contents of selenium as indicators.Then, the purity,molecular weight,infrared spectroscopy,thermophysical properties and antitumor activity of the seleny-lated polysaccharides were determined.Results showed that the optimum conditions for preparing selenylated polysaccharides from the extract residue of S.glabra(Thunb.)Nakai were at 70 ℃ for 7 h with 1.0％ nitric acid using 1.5 g barium chloride as catalyst.Under the optimum condition,the physicochemical properties of the derivatives were measured and the results showed that the total carbohydrate content was(94.89 ± 0.83)％,the yield was(21.93 ± 0.85)％,the content of selenium was(944.54 ± 13.91)μg/g,the molecular weight was 1 339 kD. In vitro antitumor activity indicated that exposure of HepG2 cells to the increasing concentrations of the crude polysaccharide from the residue of S.glabra(Thunb.)Nakai and its selenylated products decreased cell viability in dose-dependent and time-dependent manner.The selenium polysaccharide demonstrated a better antitumor activity compared with the raw polysaccharide,which could be explored as a potential antitumor drug from abandoned extracted residue for the functional foods and pharmaceutical industries.

Objective To investigate the cumulative effective dose (CED) of ionizing radiation received by patients with Crohn's disease(CD) and to identify the risk factors associated with high levels of radiation in patients with Crohn's disease. Methods A total of 230 patients were enrolled. The classification of CD was according to the Montreal standards, and the CED of each patient was calculated retrospectively based on standards tables. High levels of radiation was defined as no less than 50 mSv CED. Patients who accepted no less than 50 mSv CED were assigned to high level of the radiation group, and those who accepted simultaneously less than 50 mSv CED were assigned to the control group. The risk factors for patients associating with high levels of radiation were analyzed by Logistic regression. Results CT enterography and abdominopelvic CT accounted for 52. 1％ and 39. 6％, respectively, and add up to 91. 7％ of total CED. The mean CED received per patient was 34. 07 mSv (95％ CI:30. 845～37. 304), and 51 patients (22. 2％ of total patients) with CD were exposed to no less than 50 mSv CED. Patients with long disease duration, surgical intervention, ileal location, stricturing or penetrating pattern received a higher dose of radiation. In a Logistic regression, stricturing or penetrating pattern(OR =3. 711, 95％ CI:2. 239 ～ 6. 151, P ＜0. 001) and the requirement for azathioprine (OR =4. 218, 95％ CI: 1. 221 ～14. 579,P=0. 023) were independent risk factors for the high levels of radiation in CD. Conclusion More than one in five of patients with CD are exposed to high levels of ionizing radiation, mainly caused by CT examination. Stricturing or penetrating pattern and the usage of azathioprine are independent risk factors for the high levels exposure of radiation in CD patients. During the clinical management and follow-up, it is important to either monitor the effective dose received per patient, minimizing unnecessary CT examination, or to transform to use no radiation imaging examination, such as MR enterography.