It was demonstrated that Sphingosine kinase 1 (SphK1) promotes tumor progression and confers the malignancy phenotype of colorectal cancer by activating the focal adhesion kinase (FAK) pathway. However, further clarification is required to determine if SphK1 promotes the metastasis of colorectal cancer by inducing epithelial-mesenchymal transition (EMT), and its mechanisms have not been fully elucidated. Immunohistochemistry staining was used to detect protein expression in normal colonic mucosa tissues and colorectal cancer tissues. Cells were transfected to overexpress SphK1, downregulate SphK1 or downregulate FAK. An MTT assay was used to detect the drug toxicity to cells. Transwell and wound healing assays were used to detect cell migration ability. Reverse transcription-polymerase chain reaction and western blot analysis were used to detect the expression of mRNA and protein, respectively. Scanning electron microscopy was used to observe the microvilli and pseudopodia of the cells. The analysis of protein expression in 114 human colorectal cancer tissues demonstrated that the expressions of SphK1, FAK, phosphorylated (p)-FAK, E-cadherin and vimentin were associated with the metastasis of colorectal cancer. Furthermore, the patients with colorectal cancer with SphK1-positive cancer demonstrated poorer prognosis compared with SphK1-negative cancer. FAK knockdown and SphK1 knockdown of human colon cancer RKO cells inhibited the EMT and migrational potency, along with the expression of p-FAK, p-protein kinase B (AKT) and matrix metalloproteinase (MMP)2/9. In contrast, SphK1 overexpression promoted EMT, migrational potency, and the expression of p-FAK, p-AKT and MMP2/9 in HT29 cells. Additionally, the EMT and migrational potency of SphK1-overexpressing HT29 cells was suppressed by a FAK inhibitor, and the expression of p-FAK, p-AKT and MMP2/9 was suppressed by blocking the FAK pathway. In conclusion, SphK1 promoted the migration and metastasis of colon cancer by inducing EMT mediated by the FAK/AKT/MMPs axis.
Sphingosine kinase 1 (SphK1) is a master kinase that catalyzes the synthesis of sphingosine 1 phosphate and participates in the regulation of cell proliferation and autophagy. The present study aimed to assess the effects of the activation of the SphK1/extracellular signal-regulated kinase (ERK)/phosphorylated (p-)ERK pathway in the regulation of autophagy in colon cancer (HT-29) cells. Inverted fluorescence microscopy was used to detect the expression of green fluorescent protein (GFP) in the SphK1-overexpressing HT-29 cells [SphK1(+)-HT-29] and the negative control HT-29 cells (NC-HT-29). Western blotting was used to detect the protein expression levels of SphK1, ERK1/2, p-ERK1/2, as well as those of the autophagy-associated markers LC3A, ATG5, and ULK1. Protein localization and expression of the LC3A antibody were detected by immunofluorescence. The results demonstrated that GFP was similarly expressed in SphK1(+)-HT-29 and NC-HT-29 cells. However, significantly increased SphK1 mRNA and protein expression levels were detected in SphK1(+)-HT-29 cells compared with in NC-HT-29 cells, which resulted in upregulated ERK/p-ERK. Furthermore, the protein expression levels of the three autophagy-associated markers increased. LC3A protein was localized in the cytoplasm of SphK1(+)-HT-29 cells, indicating autophagy. In summary, the findings of the present study suggested that activation of the SphK1/ERK/p-ERK pathway promotes autophagy in colon cancer HT-29 cells.
Systematic chemotherapy is indispensable for gastric cancer patients with advanced stage disease, but the occurrence of chemoresistance drastically limits treatment effectiveness. There is a tremendous need for identifying the underlying mechanism of chemoresistance. NIK‑ and IKKβ‑binding protein (NIBP) (also known as TRAPPC9, trafficking protein particle complex 9) is a regulator of the cytokine‑induced NF‑κB signaling pathway which has been proven to play pivotal roles in the progression of various malignancies. Nevertheless, it is still ambiguous whether NIBP is involved in the chemoresistance of gastric cancer. The aim of the present study was to investigate the effect of NIBP on chemotherapy resistance of gastric cancer (GC) and to research the mechanisms of Ginkgo biloba extract 761 (EGb 761®) on reversing chemoresistence which has been confirmed in our previous study. In the present study, the results of immumohistochemisty revealed that the positive staining rates of NIBP, NF‑κB p65 and NF‑κB p‑p65 in gastric cancer tissues were obviously higher than those in normal tissues. Furthermore, a close correlation was found to exist between the expression of NIBP and NF‑κB p65 (p‑p65) in gastric cancer tissues. Moreover, the overexpression of NIBP was closely related to tumor differentiation, depth of invasion, clinical stage and lymphatic metastasis in gastric cancer. Western blot analysis, real‑time PCR, MTT assay and flow cytometric analysis were performed and the results demonstrated that compared with the gastric cancer SGC‑7901 cells, the expression of NIBP, NF‑κB p65, NF‑κB p‑p65 and mesenchymal marker vimentin were significantly increased in gastric cancer multidrug‑resistant SGC‑7901/CDDP cells, and the epithelial cell marker ZO‑1 was significantly decreased. Meanwhile, it was found that SGC‑7901/CDDP cells were accompanied by spindle‑like mesenchymal appearance and upregulation of stem cell marker CD133 which has been verified to be an upstream regulatory gene of epithelial‑mesenchymal transition (EMT). Further research confirmed that downregulation of NIBP by Ginkgo biloba extract (EGb) 761 EGb 761 suppressed the cis‑diamminedichloroplatinum(II) (CDDP)‑induced NF‑κB signaling pathway, EMT and the expression of CD133 in SGC‑7901 and SGC‑7901/CDDP cells. Altogether, these data indicate that the NIBP‑regulated NF‑κB signaling pathway plays a pivotal role in the chemoresistance of gastric cancer by promoting CD133‑induced EMT.
Kashin-Beck disease (KBD) is a chronic osteochondropathy with unclear pathogeny. In this study, we compared the microRNA expression profiles of 16 KBD patients, 16 osteoarthritis (OA) patients and 16 rheumatoid arthritis (RA) patients and 16 healthy controls in their blood specimens. miRNAs expression profiling was performed using Exiqon miRCURY LNATM miRNAs Array. miRNAs target genes were predicted using miRror suite. Another independent mRNA expression profile dataset of 20 KBD patients and 15 healthy controls were integrated with the miRNA expression profiles of KBD. We identified 140 differently expressed miRNAs in KBD vs. Controls. GO enrichment analysis found that hypoxia, Wnt receptor signaling pathway and vitamin B6 biosynthesis related GO terms were significantly overrepresented in the target genes of differently expressed miRNAs in KBD vs. Control. 18 differently expressed common miRNAs were identified in KBD vs. Control, KBD vs. OA and KBD vs. RA. Integrating the lists of differently expressed miRNA target genes and mRNA differently expressed genes detected 6 common genes for KBD. Our results demonstrated the altered miRNAs expression profiles of KBD comparing to healthy controls, OA and RA, which provide novel clues for clarifying the mechanism of KBD.
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