Identification and validation of mitophagy-related signatures as a novel prognostic model for colorectal cancer.

Background: Colorectal cancer (CRC) is one of the most commonly diagnosed cancers in the world. Mitophagy is associated with tumorigenesis and development of malignancy. However, the specific role of mitophagy has yet not been systematically explored in CRC. Methods: The RNA-sequencing dataset of CRC from The Cancer Genome Atlas (TCGA) and microarray data of gene expression profiles of CRC from Gene Expression Omnibus (GEO) were downloaded. Mitophagy-related gene sets were obtained from the Pathway Unification database. The package "limma" was used for differential gene expression analysis. Kaplan-Meier (KM) survival analyses were utilized to evaluate the prognostic value of the mitophagy regulators. Single-sample gene set enrichment analysis (ssGSEA) was used to estimate the infiltrating immune cells and the activity of immune response. The ConsensusClusterPlus algorithm was used to determine mitophagy-related subtypes. Principal component analysis (PCA) was used to create composite measurement of mitophagy scores. The R packages "survminer" and "ReGlot" were used to plot the nomogram and calibration curves. Results: Integrated analysis of the GEO and TCGA databases revealed some common differentially expressed genes (DEGs) in CRC. MFN2, UBB, PINK1, and PRKN were significantly downregulated in CRC samples as compared to normal samples, and other genes were significantly upregulated in CRC samples. KM survival analyses showed that high expression of ATG12 and MAP1LC3B predicted a poor prognosis, whereas high expression of TOMM22 and TOMM40 predicted a better prognosis. Mitophagy showed significant correlation with immune-related pathways in CRC samples. We identified 2 distinct CRC subtypes with different mitophagy accumulation, of which subtype B had better prognosis and immune activity. The mitophagy score may be employed as a new and efficient clinical predictor in conjunction with other clinical indicators to predict the prognosis of CRC patients. Conclusions: We systematically investigated the CRC heterogeneity with reference to mitophagy based on bioinformatics analyses, and the findings of this study might provide some guidance for future research into potential biomarkers for diagnosis and prognosis prediction of CRC patients.

Proteomic screening of potential N-glycoprotein biomarkers for colorectal cancer by TMT labeling combined with LC-MS/MS.

BACKGROUND AND AIMS: Colorectal cancer (CRC) is part of the most widespread malignant tumors. At present, colonoscopy is a routine procedure in the diagnosis of CRC, but it is traumatic. Carcinoembryonic antigen, CA199, and CA242 are common serum markers for the diagnosis of CRC; however, they do not demonstrate satisfactory specificity and sensitivity for the diagnosis of CRC. Hence, Now it is necessary to screen many valuable serum biomarkers for CRC, proteomics methods have been used to investigate PTMs such as glycosylation of proteins with prominent roles in the occurrence and development of tumors. METHODS: This study screens altering glycosylated proteins of CRC tissues using LC-MS/MS quantitative glycoproteomics, and then these candidate biomarkers for CRC are further validated by serum glycoproteomics. RESULTS: The results of glycoproteomics in CRC tissues show that the abundance of 160 and 79 glycerogelatin proteins was obviously upregulated and downregulated compared with their adjacent tissues(P < 0.05). Bioinformatics analysis suggests that these molecules are mainly involved in many biological processes, including skeletal system development, collagen fibril organization, and receptor-mediated endocytosis. Results of serum glycoproteomics show that the changing trends of 2 protein glycosylation were consistent with MS results of CRC tissues, including ICAM1and APMAP. Areas under the ROC curve (AUC) results confirm that ICAM1and APMAP as early immune diagnosis markers of CRC has excellent sensitivity and specificity. CONCLUSION: The ICAM1 and APMAP may serve as a potential tumor marker for CRC.

Maclurin protects against hydroxyl radical-induced damages to mesenchymal stem cells: antioxidant evaluation and mechanistic insight.

Maclurin, an exceptional member of phytophenol family, was found to effectively protect against mesenchymal stem cells (MSCs) oxidative damage induced by hydroxyl radical (OH) at 62.1-310.5 µM. Antioxidant assays indicated that maclurin could efficiently protect DNA from OH-induced damage at 114.6-382.2 µM, and scavenge OH, DPPH (1,1-diphenyl-2-picrylhydrazyl radical), ABTS(+) (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid radical), and bind Cu(2+) (IC50 values were respectively 122.87 ± 10.14, 10.15 ± 0.85, 0.97 ± 0.07, and 133.95 ± 11.92 µM). HPLC-DAD and HPLC-ESI-MS/MS analyses of the end-product of maclurin reaction with DPPH clearly suggested that maclurin (m/z = 261.12 [M-H](-)) donated two hydrogen atoms to DPPH (m/z = 394.06 [M](+)) to form ortho-benzoquinone moiety (λmax = 364 nm; m/z = 259.06 [M-H](-), loss of m/z = 28) and DPPH2 molecule (m/z = 395.03, 396.01), via hydrogen atom transfer (HAT) or sequential electron (e) proton transfer (SEPT), not radical adduct formation (RAF) mechanisms. Therefore, we concluded that: (i) maclurin can effectively protect against OH-induced damages to DNA and MSCs, thereby it may have a therapeutic potential in prevention of many diseases or MSCs transplantation; (ii) a possible mechanism for maclurin to protect against oxidative damages is OH radical-scavenging; (iii) maclurin scavenges OH possibly through metal-chelating, and direct radical-scavenging which is mainly via HAT or SEPT mechanisms; and (iv) the protective and antioxidant effects of maclurin can be primarily attributed to ortho-dihydroxyl groups, and ultimately to the relative stability of the ortho-benzoquinone form.