Fig 1.
LOXL1 was identified as a PD-associated candidate gene in GC.
a. LOXL1 mRNA expression in 223 tumor and 33 normal tissues of GC patients from the TCGA dataset. b. Kaplan-Meier survival curve of 223 GC patients from the TCGA dataset based on LOXL1 mRNA expression; log-rank test, n = 223, P < 0.01. c. LOXL1 mRNA expression in GC patients with PD compared with that in GC patients without PD from the GSE15459 dataset. PD negative, n = 142, PD positive, n = 32; Student's t-test P < 0.001. d. LOXL1 mRNA expression in highly disseminated peritoneal GC cells (As44) compared with the control cells (HSC44), examined by RT-qPCR; Student's t-test P < 0.001.
Fig 2.
LOXL1 expression was found to be a prognostic factor for overall survival of GC patients.
a. Immunochemistry staining of LOXL1 in representative GC tissues from the Kyushu validation cohort. N: normal tissue, T: Tumor tissue; original magnification, ×40, ×200. b. Kaplan-Meier survival curve of 144 GC patients from the Kyushu validation cohort based on LOXL1 mRNA expression; log-rank test, n = 144, P < 0.05.
Table 1.
LOXL1 mRNA expression and clinicopathological factors of GC cases in the Kyushu validation cohort (n = 144).
Table 2.
Univariate and multivariate analyses of clinicopathological factors affecting overall survival in GC cases from the Kyushu validation cohort (n = 144).
Fig 3.
LOXL1 overexpression may induce EMT in GC cells.
a. GSEA of GC cases from TCGA and GSE15459 datasets. TCGA dataset: NES = 2.08, FDR q-value < 0.001; GSE15459 dataset: NES = 2.01, FDR q-value < 0.05. b. Correlations between LOXL1 and EMT markers (CDH1, VIM, SNAI2, ZEB1, and PLS3) expression levels in GC patients from TCGA and GSE15459 datasets. Positive correlation was represented in blue and negative correlation was represented in red. The darker the color, the higher the correlation was (P < 0.05). The value in the box represented the correlation coefficient. c. The mRNA expressions of CDH1, VIM, SNAI2, ZEB1, PLS3, and LOXL1 were analyzed by RT-qPCR in LOXL1-overexpressing AGS cells and control cells. The expression levels were expressed as the values relative to the mRNA expression in the control cells. Student’s t-test P < 0.05. d. Western blot analysis of LOXL1, SNAI2, PLS3, and ACTIN protein expression in LOXL1-overexpressing and control cells. e. The shape of LOXL1-overexpressing and control cells (left panel); and immunofluorescence analysis of CDH2 in LOXL1-overexpressing and control cells (right panel). Original magnification, ×50, ×400. Student’s t-test P < 0.05. Scale bar is 100μm.
Fig 4.
LOXL1 overexpression promoted migration capacity of GC cells.
a. Images of in vitro wound-healing assay (left panel), and migration distance of LOXL1-overexpressing and control cells (right panel). Student's t-test P < 0.05. b. Schematic representation of the mechanism of PD promotion by LOXL.