Signature based on molecular subtypes of deoxyribonucleic acid methylation predicts overall survival in gastric cancer

BACKGROUND Gastric cancer(GC) ranks as the third leading cause of cancer-related death worldwide. Epigenetic alterations contribute to tumor heterogeneity in early stages.AIM To identify the specific deoxyribonucleic acid(DNA) methylation sites that influence the prognosis of GC patients and explore the prognostic value of a model based on subtypes of DNA methylation.METHODS Patients were randomly classified into training and test sets. Prognostic DNA methylation sites were identified by integrating DNA methylation profiles and clinical data from The Cancer Genome Atlas GC cohort. In the training set, unsupervised consensus clustering was performed to identify distinct subgroups based on methylation status. A risk score model was built based on Kaplan-Meier, least absolute shrinkage and selector operation, and multivariate Cox regression analyses. A test set was used to validate this model.RESULTS Three subgroups based on DNA methylation profiles in the training set were identified using 1061 methylation sites that were significantly associated with survival. These methylation subtypes reflected differences in T, N, and M category, age, stage, and prognosis. Forty-one methylation sites were screened as specific hyper-or hypomethylation sites for each specific subgroup. Enrichment analysis revealed that they were mainly involved in pathways related to carcinogenesis, tumor growth, and progression. Finally, two methylation sites were chosen to generate a prognostic model. The high-risk group showed a markedly poor prognosis compared to the low-risk group in both the training [hazard ratio(HR) = 2.24, 95% confidence interval(CI): 1.28-3.92, P < 0.001] and test(HR = 2.12, 95%CI: 1.19-3.78, P = 0.002) datasets.CONCLUSION DNA methylation-based classification reflects the epigenetic heterogeneity of GC and may contribute to predicting prognosis and offer novel insights for individualized treatment of patients with GC.

Structure and function of Septin 9 and its role in human malignant tumors

The treatment and prognosis of malignant tumors are closely related to the time when the tumors are diagnosed;the earlier the diagnosis of the tumor,the better the prognosis.However,most tumors are not detected in the early stages of screening and diagnosis.It is of great clinical significance to study the correlation between multiple pathogeneses of tumors and explore simple,safe,specific,and sensitive molecular indicators for early screening,diagnosis,and prognosis.The Septin 9(SEPT9)gene has been found to be associated with a variety of human diseases,and it plays a role in the development of tumors.SEPT9 is a member of the conserved family of cytoskeletal GTPase,which consists of a P-loop-based GTP-binding domain flanked by a variable N-terminal region and a C-terminal region.SEPT9 is involved in many biological processes such as cytokinesis,polarization,vesicle trafficking,membrane reconstruction,deoxyribonucleic acid repair,cell migration,and apoptosis.Several studies have shown that SEPT9 may serve as a marker for early screening,diagnosis,and prognosis of some malignant tumors,and have the potential to become a new target for anti-cancer therapy.This article reviews the progress in research on the SEPT9 gene in early screening,diagnosis,and prognosis of tumors.

Neuroendocrine,epigenetic,and intergenerational effects of general anesthetics

The progress of modern medicine would be impossible without the use of general anesthetics(GAs).Despite advancements in refining anesthesia approaches,the effects of GAs are not fully reversible upon GA withdrawal.Neurocognitive deficiencies attributed to GA exposure may persist in neonates or endure for weeks to years in the elderly.Human studies on the mechanisms of the long-term adverse effects of GAs are needed to improve the safety of general anesthesia but they are hampered not only by ethical limitations specific to human research,but also by a lack of specific biological markers that can be used in human studies to safely and objectively study such effects.The latter can primarily be attributed to an insufficient understanding of the full range of the biological effects induced by GAs and the molecular mechanisms mediating such effects even in rodents,which are far more extensively studied than any other species.Our most recent experimental findings in rodents suggest that GAs may adversely affect many more people than is currently anticipated.Specifically,we have shown that anesthesia with the commonly used GA sevoflurane induces in exposed animals not only neuroendocrine abnormalities(somatic effects),but also epigenetic reprogramming of germ cells(germ cell effects).The latter may pass the neurobehavioral effects of parental sevoflurane exposure to the offspring,who may be affected even at levels of anesthesia that are not harmful to the exposed parents.The large number of patients who require general anesthesia,the even larger number of their future unexposed offspring whose health may be affected,and a growing number of neurodevelopmental disorders of unknown etiology underscore the translational importance of investigating the intergenerational effects of GAs.In this mini review,we discuss emerging experimental findings on neuroendocrine,epigenetic,and intergenerational effects of GAs.

Dietary exposure to di-isobutyl phthalate increases urinary 5-methyl-2′-deoxycytidine level and affects reproductive function in adult male mice

Phthalates are a large family of ubiquitous environmental pollutants suspected of being endocrine disruptors. Epidemiological studies have associated phthalate metabolites with decreased reproductive parameters and linked phthalate exposure with the level of urinary 5-methyl-2′-deoxycytidine（5mdC, a product of methylated DNA）. In this study, adult male mice were exposed to 450 mg di-isobutyl phthalate（DiBP）/（kg·day） via dietary exposure for 28 days. Mono-isobutyl phthalate（Mi BP, the urinary metabolite） and reproductive function parameters were determined. The levels of 5mdC and 5-hydroxymethyl-2′-deoxycytidine（5hmdC） were measured in urine to evaluate if their contents were also altered by DiBP exposure in this animal model. Results showed that DiBP exposure led to a significant increase in the urinary 5mdC level and significant decreases in sperm concentration and motility in the epididymis, accompanied with reduced testosterone levels and downregulation of the P450 cholesterol side-chain cleavage enzyme（P450scc） gene in the mice testes. Our findings indicated that exposure to DiBP increased the urinary 5mdC levels,which supported our recent epidemiological study about the associations of urinary 5mdC with phthalate exposure in the male human population. In addition, DiBP exposure impaired male reproductive function, possibly by disturbing testosterone levels; P450scc might be a major steroidogenic enzyme targeted by DiBP or other phthalates.