Aberrant glycosylation is a hallmark of most human cancers and affects many cellular properties, including cell proliferation, apoptosis, differentiation, transformation, migration, invasion, and immune responses. Here, we report that N-acetylgalactosaminyltransferase14 (GALNT14), which mediates the initial step of mucin-type O-glycosylation and is heterogeneously expressed in most breast cancers, plays a critical role in the invasion and migration of breast cancers by regulating the activity of MMP-2 and expression of some EMT genes. We have modulated the expression of GALNT14 by RNAi and overexpression in MCF-7 cells. Overexpression of GALNT14 significantly enhanced cell migration and invasion and promoted the proliferation of breast cancer cells. Knockdown of GALNT14 reduced clonogenicity and attenuates cell migration and cell invasion. The mRNAs for N-cadherin, vimentin, E-cadherin, MMP-2, VEGF, and TGF-β were determined by RT-qPCR involving GALNT14-overexpressing or knockdown MCF-7 cells. Expression profiling revealed the upregulation of N-cadherin, vimentin, MMP-2, VEGF, TGF-β and the downregulation of E-cadherin in GALNT14 overexpressing cells, with the opposite seen in GALNT14 knockdowns. Gelatin zymography analysis further indicated that overexpression of GALNT14 increased MMP-2 activity in MCF-7 cells. Conversely, downregulation of GALNT14 reduced MMP-2 activity. Promoter analysis revealed that GALNT14 stimulates MMP-2 expression through the AP-1-binding site. Western blot analyses showed that knockdown of GALNT14 significantly reduced the expression of an oncoprotein mucin 1 (MUC1). These findings indicate that GALNT14 contributes to breast cancer invasion by altering the cell proliferation, motility, expression levels of EMT genes, and by stimulating MMP-2 activity, suggesting GALNT14 may be a potential target for breast cancer treatment.

LGR5 plays a critical role in tissue development and the maintenance of adult stem cells in gastrointestinal tract. However, the oncogenic role of LGR5 in the development of gastric adenocarcinoma remains elusive. Here, we show that LGR5 promotes gastric adenocarcinoma cell proliferation and metastasis. We find that knock down of LGR5 or suppression of Wnt signaling pathway by inhibitor C59 arrests gastric adenocarcinoma cell proliferation and invasion. Moreover, treatment of Wnt3a, the activator of Wnt signaling pathway, partially recovers the proliferation defect observed in LGR5 knockdown gastric adenocarcinoma cells. Moreover, LGR5 facilitates β-catenin nuclear accumulation, a surrogate marker of the activation of Wnt signaling pathway. In addition, C59 treatment suppresses transcription of Axin2 and TCF1, both of which are the target genes of β-catenin in gastric adenocarcinoma cells. Gastric adenocarcinoma cells with overexpressed LGR5 form a large quantity of visible actin filaments and pseudopods, suggesting that LGR5 significantly enhances the ability of cell movement, which might capacitate gastric adenocarcinoma cells with enhanced LGR5 expression to gain invasive and migratory properties. Taken together, our results show that LGR5 contributes to cell proliferation and invasion through the activation of Wnt/β-catenin-signaling pathway in gastric adenocarcinoma cells.

Background Loropetalum chinense var. rubrum (L. chinense var. rubrum) is a precious, coloured-leaf native ornamental plant in the Hunan Province. We found an L. chinense var. rubrum tree with three different leaf colours: GL (green leaf), ML (mosaic leaf), and PL (purple leaf). The mechanism of leaf coloration in this plant is still unclear. Therefore, this study aimed to identify the metabolites and genes involved in determining the colour composition of L. chinense var. rubrum leaves, using phenotypic/anatomic observations, pigment content detection, and comparative metabolomics and transcriptomics. Results We observed that the mesophyll cells in PL were purple, while those in GL were green and those in ML were a mix of purple-green. The contents of chlorophyll a, b, carotenoids, and total chlorophyll in PL and ML were significantly lower than those in GL. While the anthocyanin content in PL and ML was significantly higher than that in GL. The metabolomics results showed the differences in the content of cyanidin 3-O-glucoside, delphinidin 3-O-glucoside, cyanidin 3,5-O-diglucoside, pelargonidin, and petunidin 3,5-diglucoside in ML, GL, and PL were significant. Considering that the change trend of anthocyanin content change was consistent with the leaf colour difference, we speculated that these compounds might influence the colour of L. chinense var. rubrum leaves. Using transcriptomics, we finally identified nine differentially expressed structural genes (one ANR (ANR1217); four CYP75As (CYP75A1815, CYP75A2846, CYP75A2909, and CYP75A1716); four UFGTs (UFGT1876, UFGT1649, UFGT1839, and UFGT3273) and nine transcription factors (two MYBs (MYB1057 and MYB1211), one MADS-box (MADS1235), two AP2-likes (AP2-like1779 and AP2-like2234), one bZIP (bZIP3720), two WD40s (WD2173 and WD1867) and one bHLH (bHLH1631) that might be related to flavonoid biosynthesis and then impacted the appearance of colour in L. chinense var. rubrum leaves. Conclusion This study revealed potential molecular mechanisms associated with leaf coloration in L. chinense var. rubrum by analyzing differential metabolites and genes related to the anthocyanin biosynthesis pathway. It also provided a reference for research on leaf colour variation in other ornamental plants.

The second corresponding author Dr. Xiaochun Yu is only affiliated with [3] Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 E. Duarte Rd, Duarte, CA 91010, USA. He is not affiliated with [1] College of Life Sciences, Hebei University, Baoding 071002 Hebei, China.