Fucosyltransferase 8 is Overexpressed and Influences Clinical Outcomes in Lung Adenocarcinoma Patients

MiR-183-5p inhibits lung squamous cell carcinoma survival through disrupting hypoxia adaptation mediated by HIF-1α/NDUFA4L2 axis

Hypoxia is a common feature of lung squamous cell carcinoma (LUSC), and hypoxia-inducible factor-1 (HIF-1) overexpression is associated with poor clinical outcome in LUSC. NADH dehydrogenase 1 alpha subcomplex subunit 4-like 2 (NDUFA4L2) is a recently identified target of HIF-1, but its roles in LUSC remain unclear. Herein, the expression and regulatory mechanisms of NDUFA4L2 were investigated in LUSC, and the influences on LUSC cell oxidative metabolism and survival of NDUFA4L2 were determined. The potential microRNA targeting to NDUFA4L2 was identified and its roles on LUSC cell were detected. We found that NDUFA4L2 were overexpressed in LUSC tissues, and that NDUFA4L2 expression correlated with shorter overall survival. NDUFA4L2 was regulated by HIF-1α under hypoxia, and NDUFA4L2 decreased mitochondrial reactive oxygen species (mitoROS) production through inhibiting mitochondrial complex I activity in LUSC cells. NDUFA4L2 silencing effectively suppressed LUSC cell growth and enhanced apoptosis by inducing mitoROS accumulation. Additionally, NDUFA4L2 was a target for miR-183-5p, and LUSC patients with high miR-183-5p levels had better prognoses. MiR-183-5p significantly induced mitoROS production and suppressed LUSC survival through negatively regulating NDUFA4L2 in vitro and in vivo. Our results suggested that regulation of NDUFA4L2 by HIF-1α is an important mechanism promoting LUSC progression under hypoxia. NDUFA4L2 inhibition using enforced miR-183-5p expression might be an effective strategy for LUSC treatment.

High-Throughput Mass Spectrometry Analysis of N-Glycans and Protein Markers after FUT8 Knockdown in the Syngeneic SW480/SW620 Colorectal Cancer Cell Model

Disruption of the glycosylation machinery is a common feature in many types of cancer, and colorectal cancer (CRC) is no exception. Core fucosylation is mediated by the enzyme fucosyltransferase 8 (FucT-8), which catalyzes the addition of α1,6-l-fucose to the innermost GlcNAc residue of N-glycans. We and others have documented the involvement of FucT-8 and core-fucosylated proteins in CRC progression, in which we addressed core fucosylation in the syngeneic CRC model formed by SW480 and SW620 tumor cell lines from the perspective of alterations in their N-glycosylation profile and protein expression as an effect of the knockdown of the FUT8 gene that encodes FucT-8. Using label-free, semiquantitative mass spectrometry (MS) analysis, we found noticeable differences in N-glycosylation patterns in FUT8-knockdown cells, affecting core fucosylation and sialylation, the Hex/HexNAc ratio, and antennarity. Furthermore, stable isotopic labeling of amino acids in cell culture (SILAC)-based proteomic screening detected the alteration of species involved in protein folding, endoplasmic reticulum (ER) and Golgi post-translational stabilization, epithelial polarity, and cellular response to damage and therapy. This data is available via ProteomeXchange with identifier PXD050012. Overall, the results obtained merit further investigation to validate their feasibility as biomarkers of progression and malignization in CRC, as well as their potential usefulness in clinical practice.

FUT2 promotes the tumorigenicity and metastasis of colorectal cancer cells via the Wnt/β‑catenin pathway

The incidence of colorectal cancer (CRC), a leading cause of cancer‑related mortality, has increased globally. Fucosyltransferase 2 (FUT2), catalyzing the α1, 2‑linked fucose in mammals, has been reported to be overexpressed in several malignant cancers, including CRC. However, the effects of FUT2 on CRC remain largely unknown. Herein, it was determined that the FUT2 expression levels in CRC tissues were higher than those in adjacent non‑tumor tissues, whereas no association with tumor stage was revealed. The results of biological functional analysis revealed that FUT2 knockdown inhibited the proliferation, migration and invasion of human CRC cells. Moreover, the knockdown of FUT2 arrested the CRC cells at the G0/G1 phase and promoted the apoptosis of human CRC cells. Western blot analysis demonstrated that the expression levels of β‑catenin, C‑myc and cyclin D1 were decreased by FUT2 knockdown in CRC cells, whereas the expression of glycogen synthase kinase‑3β and the phosphorylation levels of β‑catenin were increased. Additionally, Wnt2 was fucosylated by FUT2 in CRC cells. Furthermore, the knockdown of FUT2 inhibited the growth of human CRC in vivo. Overall, the findings of the present study suggest that FUT2 may be used as a potential diagnostic biomarker and therapeutic target for CRC treatment.